calcium handling proteins: structure, function, and modulation by exercise
TRANSCRIPT
Calcium handling proteins: structure, function, and modulationby exercise
Jamille Locatelli • Leonardo V. M. de Assis •
Mauro C. Isoldi
� Springer Science+Business Media New York 2013
Abstract Heart failure is a serious public health issue with
a growing prevalence, and it is related with the aging of the
population. Hypertension is identified as the main precursor
of left ventricular hypertrophy and therefore can lead to
diastolic dysfunction and heart failure. Scientific studies
have confirmed the beneficial effects of the physical exercise
by reducing the blood pressure and improving the functional
status of the heart in hypertension. Several proteins are
involved in the mobilization of calcium during the coupling
excitation–contraction process in the heart among those are
sarcoplasmic reticulum Ca2?-ATPase, phospholamban,
calsequestrin, sodium–calcium exchanger, L-type calcium’s
channel, and ryanodine receptors. Our goal is to address the
beneficial effects of exercise on the calcium handling pro-
teins in a heart with hypertension.
Keywords Ca2? handling proteins � Hypertrophy �Physical exercise � Heart failure � Hypertension
Introduction
The hypertension increases the risk of heart failure (HF)
which is a complex clinical syndrome caused by structural or
functional cardiac disorders that impairs the ability of one or
both ventricles to fill or to eject blood [1]. In hypertensive
patients, the myocardium has to pump blood against a high
afterload caused mainly by an increase in peripheral vas-
cular resistance. This disorder leads to a compensatory
increase in myocardial mass mainly in the left ventricle in
order to establish a normal cardiac output. This process is not
only a consequence of an afterload increase, and thus, sev-
eral mechanisms are involved, particularly the renin–
angiotensin–aldosterone system (RAAS) [2].
Cardiac hypertrophy is linked to marked alterations in
the myocardial contractility. The peak active tension
increases [3–5], and the rates of tension development and
of relaxation are slowed [6–8]. These contractile abnor-
malities are followed by alterations in the cellular calcium
transient, and as the heart hypertrophy stage progresses
toward heart failure, the amplitude of the calcium transient
decreases [9–11].
Defective excitation–contraction coupling in heart failure
is the result of alterations in key proteins required for Ca2?
homeostasis. An unbalance between the calcium handling
proteins have been associated with left ventricular dys-
function [12, 13]. A downregulation in sarcoplasmic retic-
ulum Ca2?ATPase (SERCA2a) and in the sarcoplasmic
reticulum Ca2? release channel (RyR2) associated with an
upregulation in the expression of the Na?/Ca2? exchanger
(NCX1) also have been associated with several types of
contractile dysfunction [14–16]. In addition, functional
modifications in Ca2? handling proteins without alterations
in their expression contribute to the heart failure phenotype
[17]. The Table 1 shows some studies about heart failure and
calcium handling proteins.
Modifications in cytosolic calcium [Ca2?] influence
several signaling pathways [18, 19] that regulate normal
cardiac metabolism [20] and may cause both physiological
J. Locatelli � L. V. M. de Assis � M. C. Isoldi
Institute of Exact and Biological Sciences, Federal University
of Ouro Preto, Ouro Preto, Brazil
J. Locatelli � L. V. M. de Assis � M. C. Isoldi
Laboratory of Hypertension, Campus Universitario Morro do
Cruzeiro, Ouro Preto, MG 35400-000, Brazil
M. C. Isoldi (&)
Departamento de Ciencias Biologicas, DECBI-NUPEB,
Universidade Federal de Ouro Preto (UFOP), Ouro Preto,
MG, Brazil
e-mail: [email protected]
123
Heart Fail Rev
DOI 10.1007/s10741-013-9373-z
and pathological hypertrophy [21–23]. Several Ca2? han-
dling proteins are involved in the maintenance of cardiac
contractile function. The ryanodine receptor (RyR) and
(SERCA2) are involved in the uptake of calcium into the
sarcoplasmic reticulum, while the Na?/Ca2? exchanger is
responsible for the uptake and release of this ion across the
Table 1 Some studies regarding heart failure and hypertrophy and its effects on the expression of the proteins involved in the calcium handling
in cardiac tissue
Failure Hypertrophy
Study Results Study Results
Alterations in calcium regulatory protein
expression in patients with preserved
left ventricle systolic function and
mitral valve stenosis (Leszek et al.
[125])
Significant reduction of SERCA2 in
failing hearts
The cardiac sarcoplasmic/endoplasmic
reticulum calcium ATPase: a potent
target for cardiovascular diseases
(Kawase and Hajjar [89])
Combined ablation of PLB and sarcolipin
resulted in the enlargement of left
ventricular myocytes
Angiotensin receptor blockade improves
the net balance of cardiac Ca2?
handling related proteins in
sympathetic hyperactivity-induced
heart failure (Ferreira et al. [170])
Reduction in SERCA levels, increase in
NCX1 levels and phospho-Thr17-PLN
in the heart
Calsequestrin accumulation in rough
endoplasmic reticulum promotes
perinuclear Ca2? release (Guo et al.
[103])
Increase in CSQ2 in the rough
endoplasmatic reticulum regulates
calcium and thus might lead to the
development of cardiac hypertrophy
CaMKIIdeltaB mediates aberrant NCX1
expression and the imbalance of
NCX1/SERCA in transverse aortic
constriction-induced failing heart (Lu
et al. [146])
NCX1 protein levels were elevated,
whereas SERCA2 protein levels were
decreased in cardiomyocytes
Ryanodine receptor type 2 is required for
the development of pressure overload
induced cardiac hypertrophy (Zou
et al. [118])
Mouse cardiomyocytes RyR2 (±) with
aortic constriction showed less
hypertrophy when compared to the
wild type mice
Alterations of sarcoplasmic reticulum
proteins in failing human dilated
cardiomyopathy (Meyer et al. [61])
Reduction in SERCA protein levels Aberrant interaction of calmodulin with
the ryanodine receptor develops
hypertrophy in the neonatal
cardiomyocyte (Gangopadhyay and
Ikemoto [119])
Neonatal rat cardiomyocytes developed
hypertrophic response by modulating
calmodulin on ryanodine receptors
Relationship between Na?–Ca2?-
exchanger protein levels and diastolic
function of failing human myocardium
(Hasenfuss et al. [63])
Reduction in SERCA protein levels in the
heart
Early cardiac hypertrophy in mice with
impaired calmodulin regulation of
cardiac muscle Ca2? release channel
(Yamaguchi et al. [122])
Biochemical analysis of the hearts of 7-
and 10-day-old homozygous mutant
mice indicated a reduction in RyR2
protein levels and sarcoplasmic
reticulum Ca2? sequestration
Reduced Ca2? sensitivity of SERCA 2a
in failing human myocardium due to
reduced serin-16 phospholamban
phosphorylation (Schwinger et al. [67])
The phosphorylation status of PLB as
well as serine-16-PLB-
phosphorylation, were significantly
reduced in cardiomyocytes
Hypertrophy and heart failure in ice
overexpressing the cardiac sodium–
calcium exchanger (Roos et al. [175])
The NCX1 transgenic mice
(Heterozygous) and homozygous mice
exhibited hypertrophy and blunted
responses with b-adrenergic
stimulation
Calcium handling abnormalities
underlying atrial arrhythmogenesis and
contractile dysfunction in dogs with
congestive heart failure (Yeh et al.
[171])
Reduction in total RyR2 and
calsequestrin expression in
cardiomyocytes
Decreased cardiac L-type Ca2? channel
activity induces hypertrophy and heart
failure in mice (Goonasekera et al.
[130])
Adult cardiomyocytes from the hearts of
mice heterozygous for the gene
encoding the pore-forming subunit of
LTCC at 10 weeks of age showed a
decrease in LTCC current and a modest
decrease in cardiac function
Mechanisms of altered excitation–
contraction coupling in canine
tachycardia-induced heart failure, II:
model studies (Winslow et al. [172])
Reduction of SERCA and NCX protein
levels in canine cardiomyocytes
Rapid expression of the Na?–Ca2?
exchanger in response to cardiac
pressure overload (Kent el al. [138,
143])
Cardiomyocyte Na? influx was found to
produce a rapid result in terms of both
enhanced Na?–Ca2? exchanger
expression and accelerated synthesis of
general and contractile proteins, the
hallmarks of cardiac hypertrophy
Cellular and molecular determinants of
altered Ca2? handling in the failing
rabbit heart: primary defects in SR
Ca2? uptake and release mechanisms
(Armoundas et al. [173])
Reduction in SERCA and
phospholamban mRNA levels
Downregulation in the protein levels of
RyR, SERCA, and phospholamban;
upregulation in protein levels of NCX
in rabbit cardiomyocytes
Reduced myocardial sarcoplasmic
reticulum Ca2?-ATPase protein
expression in compensated primary
and secondary human cardiac
hypertrophy (Schotten et al. [176])
In hypertrophic obstructive
cardiomyopathy SR Ca2?-ATPase
expression was reduced by about 30 %
compared to nonfailing myocardium,
whereas the expression of
phospholamban, calsequestrin, and the
Na?/Ca2?-exchanger was unchanged
Defective Ca2? handling proteins
regulation during heart failure (Hu
et al. [99])
Downregulation in RyR2-associated
proteins, SERCA2a, phospholamban
phosphorylation at Ser16 (PLB-S16)
and Thr17 (PLB-T17), L-type Ca2?
channel and NCX in the heart
Regulation of Ca2? signaling in
transgenic mouse cardiac myocytes
overexpressing calsequestrin (Jones
et al. [177])
Transgenic mice with cardiac-targeted
overexpression of canine calsequestrin
(CSQ) developed cardiac hypertrophy
Enhanced phosphorylation of
phospholamban and downregulation of
sarco/endoplasmic reticulum Ca2?
ATPase type 2 (SERCA 2) in cardiac
sarcoplasmic reticulum from rabbits
with heart failure (Currie and Smith
[174])
Reduction of SERCA and
phospholamban protein levels in
cardiomyocytes
SERCA2 pump with an increased Ca2?
affinity can lead to severe cardiac
hypertrophy, stress intolerance, and
reduced life span (Vangheluwe et al.
[82, 83])
The SERCA pump with a high Ca2?
affinity can elicit cardiac hypertrophy
Heart Fail Rev
123
sarcolemma [24]. Some studies suggest that in severe cases
of heart failure may be related due to changes in the
function and expression of those proteins as well an
imbalance in the calcium homeostasis [21, 25].
The exercise training increases cardiac function, cal-
cium sensitivity, and cardiomyocyte contractility. The goal
of this review was to survey the key proteins involved in
the calcium handling and what is so far know about the key
role of the exercise training in the function and expression
of these proteins.
Calcium handling process in cardiomyocytes
The contraction and relaxation of cardiac muscle cells are
regulated by the cycle of Ca2? between the cytoplasm and
the sarcoplasmic reticulum. The heart contraction during
systole is induced by an action potential generated by
pacemaker cells that are located in the sinus and as well in
other regions of the cardiac muscle. This action potential
induces the L-type calcium channels (CCTL) to open in
response to this stimulus. These channels are located in the
plasma membrane and, therefore, are responsible for the
influx of Ca2? into the cytoplasm of cardiomyocytes.
A cytoplasmic increase of Ca2? activates the ryanodine
receptor 2 (RyR2), which are responsible for an additional
release of Ca2? from the sarcoplasmic reticulum. The
combination of this ion influx and the additional release by
RyR2 increase the concentration of cytoplasmic Ca2? and
thus allows troponin C to bind to Ca2?, the result of this
process is myocardial contraction.
The relaxation process occurs when Ca2? is removed
from the cytoplasm. The main carrier of Ca2? through the
reticulum is SERCA2a. In addition, the exchanger Na?/
Ca2? (NCX) removes this ion through the sarcolemma. The
activity of SERCA2a is under control of a protein that
binds to the sarcoplasmic reticulum membrane, and this
protein is called phospholamban (PLN) which in its
dephosphorylated state inhibits SERCA2a; however, the
phosphorylation of PLN allows the entry of Ca2? in the
sarcoplasmic reticulum, and therefore, a faster relaxation of
the cardiomyocytes is possible [26].
The cardiomyocytes’ contractility is tightly regulated at
the cellular level. The sympathetic activation of receptors b1
activates PKA and thus amplifies the Ca2? input current that
opens RyR channels and therefore causing Ca2? release
from the sarcoplasmic reticulum. There is an increase in the
probability of channel opening through RyR phosphoryla-
tion via PKA-dependent pathway [27], which is linked with
an adapter protein, called mAKAP (AKAP6) [27, 28], and
thus, this mechanism increases Ca2? release. The opening of
RyR channels is tightly regulated by the Ca2? from the
reticulum through the sites of luminal ion sensitivity. The
Ca2?/calmodulin-dependent protein kinase II (CaMKII)
also binds and phosphorylates the RyR2 at residue Ser2815,
consequently by this mechanism, and there is an increase in
the probability of RyR2 channel opening [29].
In order to facilitate the coordination of Ca2? induced
Ca2? release, groups of RyR2 channels are located in
strategic areas in the reticulum membrane (known as units
of calcium release), and those units are next to the CCTL
within the T-Tubules sarcolemma [24, 30]. In diastolic
Ca2? concentrations, the troponin I inhibits the interaction
between the myosin and actin monomers [31]. The Ca2?
influx through the active CCTL, that are physically near
and functionally coupled with the RyR2 [32], induces the
release of synchronized Ca2? [33, 34]. This release gen-
erates a transient concentration of intracellular Ca2? that
triggers the contraction of the cardiac muscle cells.
The concentration of cytosolic Ca2? increases during
contraction and is immediately followed by the removal of
this ion from the cytoplasm and therefore resulting in
deactivation of the contractile machinery and myocardial
relaxation during diastole (Fig. 1).
The cytosolic Ca2? is pumped back to the endoplasmic
reticulum by SERCA2a. The SERCA2a uses the energy
provided by the hydrolysis of ATP to transport Ca2?
across the membrane. Two Ca2? ions are transported for
each ATP molecule hydrolyzed [26, 35]. Ca2? is also
transported out of the cell via NCX1, which is highly
expressed in heart. In the hearts of rats, 7 % of Ca2? is
removed by NCX1, 92 % by SERCA2a, and the 1 % left
is removed by other systems [36]. The Ca2? cycling is
presented in Fig. 2.
Calcium homeostasis and cardiac hypertrophy
The hypertrophy of the heart can be considered at the first
moment as adaptive, and therefore, it allows the heart to
increase the cardiac output and to compensate hemody-
namic issues. It has been shown in an animal model that the
inhibition of the cardiac hypertrophy caused by cyclo-
sporine (CsA) results in an increase of mortality mainly
due to heart failure [37].
However, an epidemiological study showed that the
chronic cardiac hypertrophy is an independent factor when
related to morbidity and mortality in the general population
and also for the portion of this population committed with
hypertension [38].
The development of cardiac hypertrophy involves
hemodynamic and neurohormonal changes as well as
activation of growth factors, cytokines, and phosphoryla-
tions of proteins. Current evidences highly suggest that
phosphorylations of proteins play a key role in the cardiac
remodeling process [39]. These alterations in the heart
Heart Fail Rev
123
result in larger cardiomyocytes and sarcomeres. Initially,
the cardiac hypertrophy is considered beneficial because it
compensates an increase in the heart’s workload; however,
in the long term, it becomes maladaptive and therefore
results in cardiac dysfunction [40]. It is well known that
hypertrophy process in cardiomyocytes is followed by an
Fig. 1 Characteristics of type of cardiac hypertrophy: concentric and eccentric. Adapted from Bernardo et al. [179]
Fig. 2 Illustration of a cardiac
myocyte and Ca21 handling.
The cycling of Ca2? is indicated
by arrows. AC, adenylate
cyclase; b-AR, b-adrenergic
receptor; DHPR,
dihydropyridine receptor; IP3R,
InsP3 receptor. Adapted from
Lygren and Tasken [180]
Heart Fail Rev
123
increase in collagen synthesis that leads to the development
of myocardial fibrosis.
Myocardial fibrosis leads to an increase in stiffness of
the cardiomyocytes, which is primarily responsible for
contractile abnormality and cardiac dysfunction [41].
The stress of the endoplasmic reticulum (ER) might be a
crucial factor to the development of cardiac hypertrophy,
which may be directly related to induction of the protein
synthesis in cardiomyocytes and thus enhancing the
hypertrophy process. However, the exact mechanisms
underlying this phenomenon is yet unknown, but a growing
body of evidence suggests that these mechanisms can be
divided in two big groups: the first one, there are the pro-
tein kinases and serine-threonine kinases, such as PI3K,
AKT, GSK-3, CaMKII, PKA, MAPK, ERK, and PKC [42–
48]; in the second group, there are the phosphatase pro-
teins, such as the PP1 and calcineurin [49]. The enzymes
from both groups seem to play a role in the cardiac
remodeling [39].
A study showed that the cardiac hypertrophy induced by
the physiological stress is dependent on the levels of
cytosolic Ca2?. It is known that CsA is able to inhibit the
development of cardiac hypertrophy [50]. Nevertheless, the
heart failure may be also induced by exposure to CsA and
therefore increases the risk of death in rats in a pressure
overload model.
It has been suggested that calcineurin (CAN) and the
family of nuclear factor of activated T cells (NF-AT) are
potential therapy targets to the newer anti-hypertrophic
agents [50].
Angiotensin II (Ang II) is a major component of the
renin–angiotensin–aldosterone system (RAAS) and an
important mediator of vascular tone [51]. Ang II exerts its
biological effects through the G-protein-coupled angio-
tensin II type 1 (AT1) and type II (AT2) receptors. There is
growing evidence that some of these pathways are G-pro-
tein independent [53]. In the heart, the majority of the
pathological effects of chronically elevated Ang II are
thought to be mediated through AT1.
The calcium mobilization induced by Ang II and phen-
ylephrine increases the cytosolic levels of Ca2? in cardio-
myocytes and then increases the development of cardiac
hypertrophy [54]. These effects seem to be mediated by
dephosphorylation of NF-AT3, and its translocation to the
nucleus in order to interact with the genes that are respon-
sible for the hypertrophic process. Therefore, a mutated NF-
AT3 that retained function and was constitutively expressed
in the hearts of transgenic mice produced ventricular wall
fibrosis and enlargement of the cardiomyocytes [54]. This
result shows the important role of the Ca2?, CAN, and NF-
AT3 pathways in the cardiac hypertrophy.
In a recent study, Valente et al. [55] showed that Ang II
in vitro and in vivo induced hypertrophy in cardiomyocytes
through the adapter protein CIKS (Connection to IKK and
SAPK/JNK). Ang II induced the expression of CIKS in
cardiomyocytes, and both CIKS induction and CIKS
dependent cardiomyocyte hypertrophic growth are medi-
ated through angiotensin receptor 1 (AT1) and NAPDH
oxidases (Nox2) dependent reactive oxygen species (ROS)
generation. Also, in the same study, Ang II increased AT1
physical association with Nox2 both in vitro and in vivo:
ROS generation and physical association of CIKS with
Inhibitor of nuclear factor kappa-B kinase subunit beta
(IKKb). These results suggest that CIKS is a potential
therapeutic target in cardiac hypertrophy, adverse remod-
eling, and congestive heart failure.
In cardiomyocytes, the following compounds: thapsi-
gargin, tunicamycin, and Ang II increase the release of
atrial natriuretic peptide (ANP): the synthesis of protein
and the cell surface area. These alterations in cardiomyo-
cytes lead to cardiac hypertrophy. The stress induced by
the treatment for thapsigargin in cardiomyocytes increases
the cytosolic levels of Ca2?, which may be related to a
reduction in SERCA activity. On other hand, cardiomyo-
cytes that were first treated with care and subsequently with
thapsigargin showed a reduction in the cardiac hypertrophy
and also on the ANP mRNAs levels [56].
Further studies are needed in order to elucidate the
mechanism behind the agents that induce ER stress and the
role of the proteins cited above in the development of
hypertrophy.
SERCA2a
A sarcoplasmic reticulum Ca2?-ATPase (SERCA) that
mediated the transport of Ca2? was discovered 40 years
ago [57]. SERCA2a is the most expressed isoform in the
heart. This Ca2? pump is composed of a single polypeptide
with 110 kDa, and it is located in both endoplasmic
reticulum and sarcoplasmic reticulum membrane.
The SERCA2a plays a central role in the Ca2? cycle and
in excitation–contraction coupling process of the cardio-
myocytes. The SERCA2a transports Ca2? to the sarcoplas-
mic reticulum during the diastole. Several isoforms were
identified in mammals, and these proteins are encoded by
three different genes which are known as SERCA1, 2, and 3.
The Ca2?/calmodulin-dependent protein kinase II
(CaMKII) regulates the SERCA2a function by direct
phosphorylation through phospholamban (PLN) interaction
[58]. The physical interaction between SERCA2a and PLN
is mediated by specific residues in the membrane. It is
believed that these residues interact directly with SER-
CA2a in order to produce an inhibitory effect due to
alteration in SERCA2a tertiary structure and therefore
resulting in a reduction on its affinity for Ca2? [59, 60].
Heart Fail Rev
123
Regarding the relevance of Ca2? transport to contractile
activity, it has been clearly demonstrated that specific
inhibition of SERCA2a by thapsigargin interferes in
cardiomyocytes contractile response to excitation of the
membrane [61].
Changes in SERCA2a function and in cytosolic signal-
ization of Ca2? are pathogenic features of cardiac hyper-
trophy and heart failure [25, 33, 62, 63]. A reduction in
SERCA2a expression and/or function has been related by
many groups [16, 64–71].
The reduction in SERCA2a function may contribute to a
decrease in the sarcoplasmic reticulum Ca2? load in heart
failure [25]. Dhalla et al. [68] showed a reduction in Ca2?
transport by SERCA2a in rats with heart failure. Two
studies have also related low concentration of Ca2? in
cardiomyocytes with heart failure [57, 72].
It is known that the exercise training modulates either
the improvement or normalization on SERCA2a expres-
sion and also regulates its function. Therefore, these
actions may contribute to the calcium homeostasis in
cardiomyocytes.
Mou et al. [70] demonstrated that training on treadmill
for 5 weeks long was able to restore the expression levels
of SERCA2a in endocardial cells of mice in an advance
stage of heart failure (13 weeks post-myocardial infarc-
tion). Buttrick et al. [71] related a normalization on the
levels of SERCA2a compared to the sedentary animals in
rats with renovascular hypertension submitted to 6 weeks
of swimming protocol.
The practice of regular exercise training can improve
cardiac performance in heart failure. This improvement
seems to be related to the normalization in several aspects
of myocardial physiology. However, further studies are
needed to evaluate their possible effects on the expression
of SERCA2a and its relationship with calcium homeostasis
in cardiomyocytes.
Phospholamban
The phospholamban (PLN) was discovered by Arnold Kats
and colleagues in 1974 [72]. It is a 52 amino acid integral
membrane protein, and it is highly expressed in cardiac
muscle and also in small amounts in slow-twitch skeletal
muscles, smooth muscles, and endothelial cells [73, 74].
This protein can be phosphorylated in three different sites
after an adrenergic stimulation: Ser16 by cyclic-AMP-
dependent protein kinase A (PKA) and on Thr17 by
CaMKII.
The dephosphorylated PLN may contribute to an
increase on Ca2? levels in the sarcoplasmic reticulum and
then leading in a deficiency in the transport of calcium by
SERCA2a in the presence of phosphatases [34, 75].
When PLN is on dephosphorylated form, it acts as a
SERCA2a inhibitor and its phosphorylation promotes an
increase in the Ca2? transient [26, 76]. When the cytosolic
levels of Ca2? are low, PLN interacts with SERCA2a
reducing its affinity for the Ca2?. At a low cytosolic con-
centration of Ca2? and low affinity of this ion by SERCA2a
during the diastole process, a temporally inactivation of
SERCA2a may occur. When the cytosolic levels of Ca2?
increase during the systole, this ion reaches a minimal
concentration that activates SERCA2a. In rodents, the
interval between systole and diastole is very short and then
results in an uncompleted full relaxation of SERCA2a.
The inhibitory effect of the dephosphorylated form of PLN
on SERCA2a can be well demonstrated in knockout animals
for phospholamban gene. These animals present an increase
in the affinity for the calcium by SERCA2a, a reduction in the
intervals between contraction and relaxation process, and also
an increase in the rate of cardiac pumping [77].
Mice with superexpression of phospholamban have a
reduction on Ca2? affinity by SERCA2a and a decrease in
heart performance [78]. Flesch et al. [34] evaluated the
mRNA levels of phospholamban in the hearts of patients
with idiopathic and ischemic cardiomyopathy and reported
a significant reduction when compared to individuals
without cardiac diseases.
Collins et al. [75] and Sugizaki et al. [76] showed that
the physical exercise can promote normalization or
increase in PLN expression and also an increase in the
phosphorylated forms of this enzyme. Medeiros et al. [78]
related an increase in the phosphorylation of PLN in the
residue serine16 in mice submitted to a treadmill protocol
with a duration of 8 weeks that had heart failure induced by
overactivity of the sympathetic system.
These findings show that exercise has effects on the
regulation of expression of this protein, which is involved
directly in regulating the function of SERCA2a. Thus, we
believe that the PLN may indirectly influence on calcium
homeostasis in cardiomyocytes of animals submitted to
exercise training.
PLN, SERCA and hypertrophy
The SERCA is involved in the reuptake of Ca2? into the
sarcoplasmic reticulum (SR) and determines the SR Ca2?
content and cycles of the heart [26, 79]. Phospholamban
(PLN) and sarcolipin (SLN) are the key regulators of
SERCA pump activity in the heart; in addition, a decrease
in the expression of SERCA2a and/or increased levels of
its regulators have been attributed to the decreased SERCA
pump affinity for Ca2? in the failing myocardium [26–80]
Using adenovirus mediated expression of SERCA1a in
adult rat cardiac myocytes, it has been demonstrated that a
Heart Fail Rev
123
moderate level of SERCA1a expression can improve car-
diomyocyte contractility. However, a higher level expres-
sion of SERCA1a can impair cardiomyocyte shortening
[81]. In a mouse model, the replacement of SERCA2a by
SERCA2b, a high-Ca2?-affinity pump, in the absence of
PLN resulted in severe cardiac hypertrophy, stress intol-
erance and reduced lifespan [82, 83].
On the other hand, a study demonstrated that an over-
expression of PLN in the cardiomyocytes resulted in a
diminished Ca2? uptake by the sarcoplasmic reticule and
then contributing to a reduction in heart contractibility
in vivo [84].
The data obtained from the studies cited above dem-
onstrate an important link between SERCA and PLN
expression with the calcium homeostasis in cardiomyo-
cytes. When PLN expression is higher than SERCA2
expression, the result is a reduction in SERCA2a affinity
for the Ca2? and an increase in the amount of time that the
Ca2? stays in the cytoplasm. This leads to a loss in the
contraction and vice versa.
Other studies [85, 86] have shown that mutations of
PLN or absence of this protein [47] may cause severe
damage in the heart functionality that may culminate in
heart failure.
Asahi and colleagues induced an overexpression of
sarcolipin (SLN) that resulted in a reduction in SERCA2a
affinity for the Ca2?. Heart measurements in vivo show a
decrease in the ?dP/dt and -dP/dt and therefore resulting in
the hypertrophy of the left ventricle [87]. In contrast,
ablation of PLN or SLN individually increased the ven-
tricular or atrial function, respectively, in an isolated
muscle system but did not result in any over hypertrophy or
disease [88].
The inhibitory effect of SLN was reverted when iso-
proterenol, a b-adrenergic agonist, was added resulting in
the normalization of the contractile function. It was also
demonstrated that the basal phosphorylation by PLN was
diminished in the hearts SLN (-/-) in the presence of
isoproterenol. In addition to this, the phosphorylation by
PLN was restored to similar levels observed in the control
groups. These effects were stated by the authors as a higher
phosphorylation caused by PLN that resulted in the dis-
sociation of SLN from PLN and therefore leading to the
restoration of the SLN knockout heart contractile function
during the b-adrenergic stimulation.
Curiously, the combined ablation of PLN and SLN
resulted in enlargement of left ventricular myocytes and
development of cardiac hypertrophy. It has been suggested
that the sustained elevation of diastolic Ca2? intracellular
levels may be responsible for triggering the hypertrophic
response [89].
Microsomes prepared from hearts with SLN (-/-)
proved that SLN may bind to PLN and SERCA2a in order
to form a ternary complex. This study has also shown that
SLN has an inhibitory effect on SERCA2a through the
stabilization of the SERCA2a-PLN complex and also by
inhibiting the phosphorylation of PLN [87].
Gramolini and colleagues in a study [90] overexpressed
SLN in a mice knockout for PLN and related a decrease in
SERCA2a affinity for Ca2?, which resulted in the impair-
ment of the heart contractility, a reduction in the calcium
transient, and a decrease in Ca2? clearance from the
cytoplasm when compared to the animals PLN (-/-).
Furthermore, using the same animal model [SLN/PLB
(-/-)], the authors have shown that isoproterenol was able
to restore the Ca2? levels to those observed in PLN (-/-)
mice, and therefore, they have suggested that SLN may
mediate the b-adrenergic response.
The cells from the ventricles of the PLN (-/-) mice
have not demonstrated a hypertrophy process in response to
the isoproterenol treatment which is consistent with the
absence of PLN and its key effects in the phosphorylation
on SERCA2 [90].
The lack of isoproterenol response in cardiomyocytes of
PLN (-/-) mice along with data that show very low levels
of SLN suggests that SLN has a little physiological role in
a heath ventricle.
However, caution must be taken when we evaluate the
results from studies using knockout animals. Shanmugam
et al. [91] demonstrated that the lack of PLN expression
induces cardiomyocytes to display compensatory mecha-
nism, such as reduction on RyR expression and inactivation
of the Ca2? L-Type channels. The conclusion that loss of
either PLN or SLN can be compensated overtime to
maintain cardiac contractility, whereas the unregulated
SERCA pump can lead to abnormal Ca2? handling and can
be detrimental to cardiac contractility. The fine tuning of
SERCA pump activity by PLN and/or SLN is necessary to
maintain intracellular Ca2? homeostasis and meet the
physiological demands of the adult heart. These adjust-
ments, as we have seen, contribute to establish phenotype
and may lead to false conclusions.
The literature present so far in this review along with
few specific studies about SERCA2a have shown an
increase in the expression of Na?/Ca2? exchanger (NCX1)
in several animal models and exercise protocols. This
increase in the expression was due to the normalization of
the basal levels of expression in animals after an acute
myocardial infarction or by the increase above the normal
levels, such as in the hypertensive animals submitted to
swimming training.
As discussed before, the restoration between PLN
activity and SERCA2a activity is essential for the proper
heart function, especially in terms of contraction and
relaxation process. Therefore, the mechanism behind the
beneficial effects of physical training in the cardiac
Heart Fail Rev
123
enzymes may be related to the normalization in the activity
between PLN and SERCA.
Calsequestrin
In the 1970s, the calsequestrin (CSQ) was extracted from
the sarcoplasmic reticulum for the first time by MacLennan
and Wong [92]. Due to this enzyme’s ability to sequester
Ca2? from the cytoplasm into the reticulum, it was given
the name of calsequestrin [92]. The (CSQ) monomer shares
a very high level of homology between the domains I, II,
and III, which all have four a-helices—two bordering
either side of the core b-sheet structure.
The CSQ plays an important role in the Ca2? storage in
the sarcoplasmic reticulum. This protein is also responsible
for the control and stabilization of this ion inside the
reticulum [93].
In humans, there are two different genes that encode
CSQ1 and CSQ2. The CSQ1 is present in fast contraction
fibers; on the other hand, the CSQ2 is expressed in the heart
and slow-twitch muscle. When the CSQ2 interacts with the
ryanodine (RyR2) receptors through the interaction
between triadin and junction, a complex is then formed,-
which is responsible for the normal release of Ca2? [94].
The monomeric portions of CSQ2 may be responsible for
the protein regulatory function [95].
The RyR2 activity is inhibited by CSQ2 when the
luminal Ca2? concentration is low, and this process can be
reverted when the concentration of this ion raises [96].
There is a relationship between CSQ2 and RyR2, and it is
mediated by the integrals membrane proteins named triadin
and junctin. When the reticulum concentration of Ca2? is
low, the CSQ2 binds to triadin and junctin inhibiting the
RyR2 receptors; the interaction between CSQ2 with the
membrane proteins is inhibited with an increase in the
sarcoplasmic calcium concentration [96].
It is believed that CSQ may influence the calcium
homeostasis in cardiomyocytes. Kucerova and colleagues
[97] suggested that an overexpression of CSQ and triadin
led to normalization in sarcoplasmic reticulum (SR) Ca2?
release when compared to mice with an overexpression of
CSQ, depressed contractile function and survival rate.
These results are probably linked to cardiac fibrosis, a
lower SERCA2a expression, and a blunted response to b-
adrenergic stimulation. Thus, the triadin/CSQ ratio is a
critical modulator of the SR Ca2? signaling.
In vitro studies have elucidated how CSQ modulates the
release process of calcium induced by calcium due to CSQ
ability to capture this ion and also by its important role as
luminal sensor for the ryanodine receptors [93, 98]. The
increase in CSQ expression potentiates the process known
as Ca2? spark.
In rats with heart failure, Hu et al. [99] reported a
reduction in the calsequestrin protein levels and also on its
mRNA when compared to control animals.
Further studies are necessary to address and to under-
stand the influence of exercise on the expression of calse-
questrin in the heart, since few studies reported the
importance and effects of this important protein that is
involved in calcium release by the sarcoplasmic reticulum.
Calsequestrin and hypertrophy
It seems that sarcoplasmic reticulum is adjacent to the
nuclear envelope in cardiomyocytes [100]. Meanwhile, the
rough endoplasmic reticulum (RER) in adult cardiomyo-
cytes appears as perinuclear cisterns, and perhaps, it
includes the outer sheet of the nuclear envelope in where
the CSQ2 is synthesized by an unknown pathway [101]. It
is known that alterations in co-translocation of CSQ2
during either the cardiac hypertrophy or cardiac insuffi-
ciency may suggest an increase in the CSQ2 retention in
the RER [102]. Guo et al. [103] demonstrated that an
increase of CSQ2 in the RER may play an important role in
the local regulation of Ca2? and thus might lead to the
development of cardiac hypertrophy.
This hypothesis was tested in a cardiomyocytes cell
culture study that used an adenovirus to measure the
expression of a protein that binds to CSQ2, which is called
CSQ2-DsRed. In this study, it was reported an increase in the
expression of CSQ2 with its retention in the RER [101]. This
CSQ2 accumulation in the RER and perinuclear cisterns
allowed the study of the effects and the consequences of this
accumulation and its implications in the cardiac diseases.
The increase in the CSQ2 in the perinuclear cisterns was
enough to improve the variations on the nuclear Ca2?
transients and therefore promoting transcription factors
dependent of Ca2?, which led to the cardiomyocytes
hypertrophy [103].
More studies are required in order to understand the
calsequestrin role in the molecular mechanism that lead to
heart hypertrophy.
Ryanodine receptors
The ryanodine receptors (RyRs) were first characterized in
striated muscle, as well as, the calcium release channels
which release calcium from intracellular stores to trigger
muscle contraction [104–107]. The RyRs are tetramers of a
high molecular weight located in the sarcoplasmic reticu-
lum membrane (Fig. 3) [108]. In mammals, there are three
different genes that encode for three RyR isoforms. The
isoform, RyR2, is the most expressed in the heart, and it is
Heart Fail Rev
123
directly involved in the excitation–contraction coupling
[109].
The RyR2 plays an important role in the cardiac exci-
tation–contraction coupling. The calcium released from the
sarcoplasmic reticulum through RyR2 triggers the con-
traction process. The RyR2 have three phosphorylation
sites: Ser2030 [110], Ser2809 e Ser2815, although a study
suggests the existence of another phosphorylation site
[111]. The Ser2030 and Ser2809 residues are phosphorylated
by PKA [111], and the Ser2815 is phosphorylated by Ca2?/
calmodulin-dependent protein kinase [28].
A defective regulation of RyR2 observed in patients
with heart failure leads to an impairment of contractility
and also increases the probability of cardiac arrhythmias
[112, 113]. Both RyR mutations and chronic dysregulation
by PKA hyperphosphorylation may result in intracellular
Ca2? leak. Some studies show that a decrease in the
phosphodiesterase activity in the RyR channels may
sustain a chronic SR Ca2? leak and therefore promotes
progressive heart or muscle disease [114, 115]. A hyper-
phosphorylation of PKA results in intracellular SR Ca2?
leak [114, 116]. In heart failure condition, the levels of
protein phosphatase I (PP1) and protein phosphatase 2a
(PP2A) in the RyR2 complex are diminished and thus may
contribute to a reduced in the rate of Ser2808 dephospho-
rylation [116, 117].
There are few studies that show the influence of phys-
ical exercise on the expression and phosphorylation of
ryanodine receptors in the heart of animals or in patients
with heart disease. Medeiros et al. [78] observed that 8
weeks of swimming training are able to prevent ventricular
dysfunction and to increase phosphorylation of Ser2809
residue.
We believe that it is necessary a deeper investigation
about the influence of the exercise training in the expres-
sion and phosphorylation of ryanodine receptors in both
animals and humans with heart diseases, in order to elu-
cidate the mechanisms, which are responsible for the pro-
gression of heart diseases and the implication in the
regulation of calcium handling in cardiomyocytes.
Ryanodine channels and hypertrophy
The ryanodine type 2 receptor (RyR2) displays an impor-
tant role in the sarcoplasmic reticulum calcium liberation
and thus contributes to the contractile function of the
myocardium. On the other hand, the role of the RyR2 in the
development of the cardiac hypertrophy is not completely
known.
Zou et al. [118] analyzed mice with or without RyR2
(RyR2 (±)) gene deletion and also the wild type, the
Fig. 3 Schematic presentation
of the ryanodine receptor
(RyR2) channel complex and
presumed luminal Ca2?-
dependent interactions of
CASQ2 with the RyR2 complex
and itself. The transmembrane
domains are represented in
M1–M4. M, D, T and P
represent Monomer, Dimers,
Tetramers, and polymers,
respectively. Adapted from
Gyorke and Terentyev [181]
Heart Fail Rev
123
authors observed no morphological difference between the
cardiomyocytes, as well as no difference in the cardiac
contractibility between the groups; however, a diminished
calcium liberation from the SR in cardiomyocytes RyR2
(±) was observed. In this same study, the authors used a
pressure overload protocol induced by the aorta constric-
tion for 3 weeks and then analyzed the isolated cardio-
myocytes. The RyR2 isolated cardiomyocytes (±)
demonstrated a reduction in the Ca2? transient amplitude,
an increase in the intracellular Ca2? concentration during
the systole, and less hypertrophy when compared to the
wild type mice. The results gathered from this study highly
suggest that the RyR2 contributes to the development of
hypertrophy and to cardiac adaptation during a pressure
overload through Ca2? liberation from the SR, activation
of calcineurin, CaMKII, N-FAT, extracellular signal-reg-
ulated protein kinases and Akt.
Many studies have been shown the importance and the
involvement of the RYR receptors in the development of
cardiac hypertrophy, the majority of these studies corre-
lates the RYR activity with its modulation by the cal-
modulin (CaM) [113, 119–121]. In the RYR2 receptors,
there are two sites that CaM may bind: CaM binding
domain (CaMBD) and CaM like Domain (CaMLD). The
CaM binding in either of these domains causes the inacti-
vation of the RYR channels [113, 121].
In normal cardiomyocytes, the interaction between
CaMBD and CaMLD activates the Ca2? channels. Based
on the proposed model, the CaM binds to CaMBD, which
interacts with CaMLD and therefore causing the RYR
channel inactivation. This study suggests that CaM inhibits
the RYR2 channel activity, which in fact would help the
closing of these channels during the diastolic phase and
thus allowing a better relaxation after the systole process
[119].
Alterations in this mechanism described above may lead
to the development of different cardiac disease. In one
condition, CaM is prevented to bind to CaMBD in the
RYR2 receptor, and therefore, this causes Ca2? leak during
the diastole process. A study using genetically engineered
mice that have mutations in the CaMBD region of the
RyR2 receptor demonstrated that those mice developed
cardiac hypertrophy which resulted in death [122].
Apparently, this hypertrophy was triggered by an increase
in the Ca2? transient, CaMKII activation, and translocation
of the NFAT into the nucleus and therefore resulting in
cardiac hypertrophy [119].
The L-type calcium channels
The voltage-dependent calcium channels that participate in
the cardiomyocytes contractile function were identified in
1953 by Fatt and Katz [123]. In 1975, Hagiwara et al. [124]
suggested a new classification according to their electro-
physiological properties: the calcium channels of high and
low voltage. The Ca2? channels are voltage-dependent
multimeric protein complexes. The a1 subunit is the main
component of the complex channel. The complex consists
of four homologous domains (I–IV), each containing six
membrane segments (S1–S6) as demonstrated in Fig. 4.
The a1 subunit contains the voltage sensor of the channel,
which is formed by residues of positively charged arginine
and lysine in the S4 segment [128].
The L-type channels (LTCC) are often called ‘‘dihy-
dropyridine receptors’’ (DHPR), and its expression is more
Fig. 4 Schematic presentation
of the L-type Ca2? channel. The
a1C subunit consisting of 4
homologous repeated domains
The cytoplasmic b subunit is
formed by 2 highly conserved
domains indicated in purple.
The d subunit has a single
transmembrane segment with a
short cytoplasmic C terminus
and is linked by a disulfide
bound to the extracellular,
glycosylated a2 subunit.
Adapted from Kamp and Hell
[182]
Heart Fail Rev
123
marked in the ventricles, and therefore, the types T and L
channels are expressed in the cardiomyocytes [22].
In cardiac myocytes, the Ca2? current through the
channels of the L-type (ICa) is the main pathway for the
calcium influx from the extracellular space into cyto-
plasm. The ICa is responsible for the cardiac muscle
contraction and therefore plays an important role in the
contractile strength regulation [24, 126, 127]. The phos-
phorylation of L-type Ca2? channels increases the Ca2?
current and ion concentration in the sarcoplasmic reticu-
lum [128, 129].
Goonasekera et al. [130] suggested that a reduction in
LTCC current leads to neuroendocrine stress, with a SR
Ca2? release as a compensatory mechanism in order to
preserve the contractility, and therefore resulting in the
production of calcineurin/nuclear factor of activated T cells
(NFATc) that result in hypertrophy and in the development
of cardiac disease. Piot et al. 131] suggested that CCTL
function might be altered in a heart failure condition.
Further studies are necessary to elucidate the influence
of physical exercise on the expression levels of CCTL, in
order to understand its role in the treatment for cardio-
vascular disease.
The L-type calcium channels and hypertrophy
The calcium concentration that is able to trigger the
intracellular mechanism that lead to the cardiac hypertro-
phy is yet not clearly known. The Ca2? influx through the
LTCCs determines the contractibility of the cardiomyo-
cytes; however, many experts did not believe that an
increase in the intracellular calcium was able to trigger the
cardiac hypertrophy mechanisms. Some LTCCs are stored
in microdomains filled with Caveolin-3 (Cav3) and there-
fore are not directly involved in the heart contraction, in
addition the function of this type of LTCC are poorly
understood.
In order to evaluate the hypothesis that the LTCCs
domains containing Cav3 signalization are an enough
source of Ca2? to activate the NFAT factor and therefore
promoting the pathological hypertrophy, Makarewish
et al. [132] developed compounds that were able to
block the REM proteins of the membranes containing
Cav3.
The consequent blockade of LTCCs domains containing
Cav-3 eliminated a small fraction of the LTCC and almost
all the Ca2? influx and therefore inducing the NFAT
translocation to the nucleus, however, without reducing the
contractibility of the cardiomyocytes.
This recent study has provided evidence that the influx
of Ca2? through the LTCCs within the Cav-3 domains is
able to induce the hypertrophy process, and also, this Ca2?
influx can be selectively blocked without decreasing the
cardiac contractibility. Although, more studies are needed
in order to clarify the involvement of LTCC in the cardiac
hypertrophy.
NCX1
The Na?/Ca2? exchanger (NCX) was discovered in 1960,
but the greatest advanced in research of NCX was in 1988
[133] and 1990 [134], when Philipson and colleagues
purified and cloned the first isoform, the NCX1. After 4
years, the same group also purified and cloned the isoforms
two [135] and three [136]. In 1999, Philipson proposed a
new model of NCX1 [137]. The NCX can easily reverse
the direction of Ca2? flow depending on the cell Na?
gradient.
The (NCX) is a membrane transporter that carries one
Ca2? out of the cell in exchange for three Na? that are send
to the cytoplasm, but it may also mediate the flow of both
Ca2? and Na? across the membrane in a bidirectional way
(Fig. 5).
NCX1 is an important regulator of Ca2? homeostasis in
cardiomyocytes and alterations in its activity may affect the
contractility process. It is known that NCX1 is upregulated
at the transcriptional level in hearts with hypertrophy and
failure [62, 63, 138, 139].
Fig. 5 Proposed transport cycle for Na?/Ca2? exchanger—the
exchanger to bind either one Ca2? ion or three Na? ions. Either
binding event allows a conformational change that reorients the
accessibility of the ion-binding site across the membrane barrier. In
the forward-mode Ca2? extrusion in exchange for Na? entry occurs
by sequential steps in a clockwise direction. An animated version of
this figure is available at http://www.BiochemJ.org/bj/406/0365/bj406
0365add2.htm. Adapted from Lytton [183]
Heart Fail Rev
123
The NCX1 transcription regulation has been investi-
gated in the alterations that are present in pathological
processes, such as heart failure; in these conditions, it was
observed an increase in NCX1 expression in cardiomyo-
cytes [140, 141].
Seth et al. [142] reported an increase in the NCX1
mRNA levels in patients diagnosed with heart failure. This
finding suggests a possible adaptive mechanism due to
SERCA2a activity deficiency. Studies have been showing
an increase in transcriptional levels of NCX1 in heart
failure condition [62, 63, 98, 140, 143–145].
Lu et al. [146] reported an increase in the levels of
NCX1 protein in the hearts of animals with heart failure
induced by constriction of the aorta. In another study, using
a rat model with heart failure, Xu et al. [147] also found an
increase in NCX1 expression.
The exercise training reduced the elevated levels of NCX1
in animals with heart failure [148, 149]. Thus, we believe that
exercise training is able to improve cardiac function in ani-
mals with heart failure by regulating NCX1 expression levels
and therefore contributing to the normalization of calcium
current and homeostasis in cardiomyocytes.
Table 2 Studies demonstrating the effects of exercise training in the expression of calcium handling proteins in the cardiac tissue
Study Protocol Result
Adverse cardiac remodeling in spontaneously
hypertensive rats: acceleration by aerobic
exercise intensity (da Costa Rebelo et al.
[178])
Female SHRs were divided in four groups:
SHR controls, SHR control ? captopril,
SHR exercise, and SHR
exercise ? captopril. Rats in exercise
groups had free access to running wheels
during 26 weeks
The authors observed an increase of the
SERCA2a/NCX ratio in SHR
exercise ? captopril
Late exercise training improves nonuniformity
of transmural myocardial function in rats
with ischemic heart failure (Ait et al. [70])
Mice with heart failure trained on a treadmill
for 5 weeks (40 min/day, 5 days/week,
16 m/min)
The exercise restored the expression levels of
SERCA2a in endocardial cells of mice
Alterations in gene expression in the rat heart
after chronic pathological and physiological
loads (Buttrick et al. [71])
Rats with renovascular hypertension swam
until exhaustion (20–30 min) twice daily,
and gradually, the duration of the exercise
was increased to 75 min, twice daily, 5 days
per week for 6 weeks
The levels of SERCA2a were normalized
compared to sedentary animals
Daily exercise-induced cardioprotection is
associated with changes in calcium
regulatory proteins in hypertensive rats
(Collins et al. [75])
SHR had free access to running wheels for
6 weeks were instrumented (coronary artery
occlusion) and returned to their cages with
free access to running wheels for an
additional 4–6weeks of voluntary running
Daily exercise in the hypertensive rats reduced
the protein expression of the Na?/Ca2?
exchanger and normalized the protein
expression of phospholamban
Upregulation of mRNA myocardium calcium
handling in rats submitted to exercise and
food restriction (Sugizaki et al. [76])
The Wistar-Kyoto rats swam for 12 weeks
(60 min/day, 5 days/week)
The association between exercise and caloric
restriction increased the mRNA of
SERCA2a, NCX, PLB
Exercise training delays cardiac dysfunction
and prevents calcium handling abnormalities
in sympathetic hyperactivity-induced heart
failure mice (Medeiros et al. [78])
Mice with heart failure swam for 8 weeks
(60 min/day, 5 days/week)
Exercise training significantly increased the
expression of SERCA2 and phospho-
Ser(16)-PLN while it restored the expression
of phospho-Ser(2809)-RyR to wild type
levels
Exercise training normalizes altered calcium
handling proteins during development of
heart failure (Lu et al. [148])
The dogs with chronic heart failure ran on a
treadmill at 5.1 ± 0.3 km/h for 1 h every
morning and 1 h every afternoon for the
entire 4-week period
Rapid cardiac paced dogs subjected to daily
exercise training had improved SERCA2a
and NCX1 myocardial protein levels.
mRNA levels of SERCA2a and NCX1
paralleled the changes seen with the
corresponding protein levels. No significant
changes were detected in the expression of
RyR2 protein in hearts from sedentary, heart
failure, and exercised dogs
Low-intensity exercise training delays onset of
decompensated heart failure in
spontaneously hypertensive heart failure rats
(Emter et al. [158])
SHR with heart failure ran on a treadmill
3 days/week, 45 min/day, for 6 months
starting at 9, and 16 months of age with
sedentary age-matched counterparts. During
the first month of training, running speed
was gradually increased from 10 to
17.5 m/min
The authors found evidence of only subtle
increases in PLB and NCX1 protein
expression with exercise training
Heart Fail Rev
123
NCX1 and hypertrophy
In the majority of the cardiac failure and hypertrophy,
animal models in the current literature show an increase in
the NCX1 expression [62, 140, 144], and therefore ,it has
been widely accepted that NCX1 is a key component for
the contractile dysfunction [150, 151]. Among the calcium
handling proteins in the heart, such as SERCA2a, PLN, and
RyR2, the NCX1 is known to be always altered in heart
failure condition [152, 153].
The overexpression of NCX1 in rats along with no other
alterations in the calcium handling proteins does not lead to
contractile dysfunction in vivo [152, 153].
In this sense, it is very important to state that NCX1 has
been associated with the maintenance of the contractile
function, as well in the calcium transient in nonhumans
cardiomyocytes [154, 155].
Hypertrophy and the exercise
As stated previously in this review, the physical exercise
modulates the expression of the main calcium handling
proteins in cardiomyocytes. Alterations in intracellular
environment may result in an increase in the cytoplasmic
calcium and therefore may activate calcineurin (CAN)
followed by NFAT activation and then leading to
hypertrophy.
There are few studies that correlate the effects of the
physical exercise with the expression of the calcium han-
dling proteins; in addition, the results of these studies
highly suggest that moderate physical exercise leads to the
recovery of calcium homeostasis and therefore acts by
preventing or inhibiting the hypertrophy process. It is
known that physical training has an effect on the reversal of
the remodeling associated with a reduction in the calci-
neurin signaling pathway, which is related to the patho-
logical hypertrophy [156] or activation of Akt pathway that
is associated with physiological hypertrophy [157]. Based
on this and depending on the disease state of the heart, the
physical exercise is able to normalize the expression of a
compromised calcium handling protein. The Table 2 shows
some studies that reported the relationship between exer-
cise and the expression of calcium handling proteins.
Alterations in the expression of the calcium handling
proteins in both animal and human are the main responsible
for the alterations in the Ca2? homeostasis in cardiomyo-
cytes. Studies have shown that a reduction in the levels of
SERCA and PLN plus a reduction in the levels of PLN
phosphorylation in the heart failure are linked to systolic
and diastolic dysfunction [25, 62, 63].
Emter et al. [158] did not report any significant altera-
tions in SERCA and PLN expression in response to
treadmill exercise in heart failure animals. On other hand,
in a study using heart failure animals with 8 weeks tread-
mill protocol, it was reported an increase in the levels of
SERCA, phospho-Ser16-PLN, and phospho-Thr17-PLN.
Thus, it is necessary to analyze and to understand the
effects of the physical exercise in the expression of the
calcium handling proteins, mainly because these proteins
share a very important role in the calcium handling,
especially in hypertensive heart as well as in the heart
failure condition.
The futures perspectives
We believe that studies involving the physical exercise as
therapy should be encouraged in order to improve the
knowledge about the contraction–relaxation mechanism
and therefore improving the current treatments and also
increasing the patient life quality.
The regular physical activity is widely accepted as a
crucial factor in cardiovascular disease (CVD) prevention
[159–164]. The hypertension and heart failure represent a
serious worldwide health problem. The risk factors of
developing HF should be identified early as possible, and
the treatment should take place even before patients show
any evidence of structural heart damage.
The current physical activity recommendations for the
general population encourage at least 30 min of moderate
intensity physical activity five or more days per week;,
20 min of vigorous activity at least three times per week is
also recommended [165]. However, despite the extensive
research in this field, there are crucial gaps in our knowledge.
Several important areas have emerged that include
screening subgroups of the general population; the exactly
amount of exercise that is required for primary and sec-
ondary CVD prevention; the association between physical
exercise and CVD in underrepresented populations, such as
women, children, and ethnic minorities; clinical patient
groups; the role of physical exercise and cardiorespiratory
fitness (CRF) in predicting future risk of CVD and novel
biological and physiological mechanisms that might
mediate the inverse association between physical activity
and CVD risk [166].
The role of regular exercise and the volume of activity
required to achieve benefits in specific populations are not
well established [166]. In participants with CVD, for
example, light or moderate activity was more beneficial than
vigorous sporting activities for protection against CVD
mortality [167]. Nevertheless, recent training studies in
cardiac patients suggest that high intensity or high volume of
exercise training is more beneficial in reversing left ventric-
ular remodeling, diminishing expression of atherogenic
adhesion molecules, improving aerobic capacity, endothelial
Heart Fail Rev
123
function, and quality of life when compared with moderate
exercise intensity [168, 169].
It is possible that early detection and treatment for
hypertension plus the management of the factors that ini-
tiate heart failure may delay the progression of hyperten-
sion. We believe that physical exercise is one of the
therapeutic approaches, mainly because of its positive
effects on the levels of calcium handling proteins in
cardiomyocytes.
The necessity to better understand each subgroup of the
general population correlating with its physiological and
biochemical alterations is a growing challenge to the sci-
ence. In our view, the combination of a specific type of
physical exercise associated with a traditional drug therapy
is the forthcoming steps in the treatment for hypertension
and heart failure. In addition, further studies are necessary
in order to investigate the preventive action of the physical
exercise in the development of heart disease. In this review,
we demonstrated the huge influence of the physical exer-
cise in the calcium signalization in cardiomyocytes, and
therefore, the calcium handling process has many gaps that
yet need to be studied.
Conclusion
The better understanding of the complex calcium handling
process associated with the development of heart disease in
each subgroup of the general population will allow us in
near future a better treatment for the hypertension as well
in the cardiac hypertrophy and heart failure.
Acknowledgments Research supported by FAPEMIG-RedeToxifar,
CNPq, INCT-FAPEMIG-CNPq, Pronex Project Grant (FAPEMIG/
CNPq), and CAPES. Agradecimento ao Prof. Dr. Paulo Bastista de
Carvalho, membro do corpo docente da Notre Dame Catholic Uni-
versity of Baltimore, pela colaboracao ao longo desse trabalho.
References
1. Hunt SA, Abraham WT, Chin MS et al (2009) Focused update
incorporated into the ACC/AHA 2005 Guidelines for the
Diagnosis and Management of Heart Failure in Adults: a report
of the American College of Cardiology Foundation/American
Heart Association Task Force on Practice Guidelines: developed
in collaboration with the International Society for Heart and
Lung Transplantation. J Am CollCardiol 53(15):e1–e90
2. Weber KT, Sun Y, Guarda E (1994) Structural remodelling in
hypertensive heart disease and the roles of hormones. Hyper-
tension 23(6 Pt 2):869–877
3. Conrad CH, Brooks WW, Robinson KG, Bing OHL (1991)
Impaired myocardial function in spontaneously hypertensive
rats with heart failure. Am J Physiol 260:H136–H145
4. Gwathmey JK, Warren SE, Briggs GM, Coelas L, Feldman MD,
Phillips PJ, Callahan M Jr, Schoen FJ, Grossman W, Morgan JP
(1991) Diastolic dysfunction in hypertrophic cardiomyopathy:
effect on active force generation during systole. J Clin Invest
87:1023–1031
5. Brooksby P, Levi AJ, Jones JV (1992) Contractile properties of
ventricular myocytes isolated from spontaneously hypertensive
rat. J Hypertens 10:521–527
6. Gwathmey JK, Morgan JP (1993) Sarcoplasmic reticulum cal-
cium mobilization in right ventricular pressure-overloaded
hypertrophy in the ferret: relation to diastolic dysfunction and a
negative treppe. Pflugers Arch 422:599–608
7. Hajjar RJ, Liao R, Young JB, Fuliehan F, Glass MG, Gwathmey
JK (1993) Pathophysiological and biochemical characterization
of an avian model of dilated cardiomyopathy: comparison to
findings in human dilated cardiomyopathy. Cardiovasc Res 27:
2212–2221
8. Cerbai E, Barbieri M, Li Q, Mugelli A (1994) Ionic basis of
action potential prolongation of hypertrophied myocytes isolated
from hypertensive rats of different ages. Cardiovasc Res 28:
1180–1187
9. Moore RL, Yelamarty RV, Misawa H, Scaduto RC, Pawlush
DG, Elensky M, Cheung JY (1991) Altered Ca2 ? dynamics in
single cardiac myocytes from renovascular hypertensive rats.
Am J Physiol 260:C327–C337
10. Bailey BA, Houser SA (1992) Calcium transients in feline left
ventricular myocytes with hypertrophy induced by slow pro-
gressive pressure overload. J Mol Cell Cardiol 24:365–373
11. Beuckelmann DJ, Nabauer M, Erdmann E (1992) Intracellular
calcium handling in isolated ventricular myocytes from patients
with terminal heart failure. Circulation 85:1046–1055
12. van Deel ED, de Boer M, Kuster DW, Boontje NM, Holemans
P, Sipido KR, van der Velden J, Duncker DJ (2011) Exercise
training does not improve cardiac function in compensated or
decompensated left ventricular hypertrophy induced by aortic
stenosis. J Mol Cell Cardiol 50(6):1017–1025
13. Dupont S, Maizel J, Mentaverri R, Chillon JM, Six I, Giumm-
elly P, Brazier M, Choukroun G, Tribouilloy C, Massy ZA,
Slama M (2012) The onset of left ventricular diastolic dys-
function in SHR rats is not related to hypertrophy or hyperten-
sion. Am J Physiol Heart Circ Physiol 1; 302(7):H1524–H1532
14. Arai M et al (1993) Alterations in sarcoplasmic reticulum gene
expression in human heart failure. A possible mechanism for
alterations in systolic and diastolic properties of the failing
myocardium. Circ Res 72:463–469
15. Go LO et al (1995) Differential regulation of two types of
intracellular calcium release channels during end-stage heart
failure. J Clin Invest 95:888–894
16. Dash R, Frank KF, Carr AN, Moravec CS, Kranias EG (2001)
Gender influences on sarcoplasmic reticulum Ca2?-handling in
failing human myocardium. J Mol Cell Cardiol 33(7):1345–1353
17. Marks AR (2000) Cardiac intracellular calcium release chan-
nels: role in heart failure. Circ Res 87:8–11
18. Berridge MJ, Lipp P, Bootman MD (2000) The versatility and
universality of calcium signalling. Nat Rev Mol Cell Biol 1:11–21
19. Frey N, McKinsey TA, Olson EN (2000) Decoding calcium
signals involved in cardiac growth and function. Nat Med
6:1221–1227
20. Maack C, O’Rourke B (2007) Excitation-contraction coupling
and mitochondrial energetics. Basic Res Cardiol 102:369–392
21. Balke CW, Shorofsky SR (1998) Alterations in calcium han-
dling in cardiac hypertrophy and heart failure. Cardiovasc Res
37:290–299
22. LaPointe MC, Deschepper CF, Wu JP, Gardner DG (1990)
Extracellular calcium regulates expression of the gene for atrial
natriuretic factor. Hypertension 15:20–28
23. Richard S, Leclercq F, Lemaire S, Piot C, Nargeot J (1998)
Ca2 ? currents in compensated hypertrophy and heart failure.
Cardiovasc Res 37:300–311
Heart Fail Rev
123
24. Bers DM (2002) Cardiac excitation-contraction coupling. Nat-
ure 415(6868):198–205
25. Beuckelmann DJ, Nabauer M, Kruger C, Erdmann E (1995)
Altered diastolic [Ca2?]i handling in human ventricular myo-
cytes from patients with terminal heart failure. Am Heart J
129(4):684–689
26. MacLennan DH, Kranias EG (2003) Phospholamban: a crucial
regulator of cardiac contractility. Nat Rev Mol Cell Biol
4(7):566–577
27. Kapiloff MS, Jackson N, Airhart N (2001) mAKAP and the
ryanodine receptor are part of a multi-component signaling
complex on the cardiomyocyte nuclear envelope. J Cell Sci
114(Pt 17):3167–3176
28. Wehrens XH, Lehnart SE, Reiken SR, Marks AR (2004) Ca2?/
calmodulin-dependent protein kinase II phosphorylation regu-
lates the cardiac ryanodine receptor. Circ Res 94(6):e61–e70
29. Gomez AM, Valdivia HH, Cheng H, Lederer MR, Santana LF,
Cannell MB et al (1997) Defective excitation–contraction cou-
pling in experimental cardiac hypertrophy and heart failure.
Science 276(5313):800–806
30. Simmerman HK, Jones LR (1998) Phospholamban: protein
structure, mechanism of action, and role in cardiac function.
Physiol Rev 78(4):921–947
31. Ebashi S, Lippman F (1962) Adenosine triphosphate linked
concentration of calcium ions in a particular fraction of rabbit
muscle. J Cell Biol 14:389–400
32. Gelebart P, Martin V, Enouf J, Papp B (2003) Identification of a
new SERCA2 splice variant regulated during monocytic dif-
ferentiation. Biochem Biophys Res Commun 303(2):676–684
33. Hasenfuss G, Reinecke H, Studer R, Meyer M, Pieske B, Holtz J
et al (1994) Relation between myocardial function and expres-
sion of sarcoplasmic reticulum Ca2?-ATPase in failing and
nonfailing human myocardium. Circ Res 75(3):434–442
34. Flesch M, Schwinger RH, Schnabel P, Schiffer F, van Gelder I,
Bavendiek U et al (1996) Sarcoplasmic reticulum Ca2?ATPase
and phospholamban mRNA and protein levels in end-stage heart
failure due to ischemic or dilated cardiomyopathy. J Mol Med
(Berl) 74(6):321–332
35. Martonosi AN, Pikula S (2003) The structure of the Ca2?-
ATPase of sarcoplasmic reticulum. Acta Biochim Pol 50(2):
337–365
36. Martin V, Bredoux R, Corvazier E, Van Gorp R, Kovacs T,
Gelebart P et al (2002) Three novel sarco/endoplasmic reticulum
Ca2?-ATPase (SERCA) 3 isoforms. Expression, regulation, and
function of the membranes of the SERCA3 family. J Biol Chem
277(27):24442–24452
37. Meguro T, Hong C, Asai K, Takagi G, McKinsey TA, Olson
EN, Vatner SF (1999) Cyclosporine attenuates pressure-over-
load hypertrophy in mice while enhancing susceptibility to
decompensation and heart failure. Circ Res 84:735–740
38. Morisco C, Sadoshima J, Trimarco B, Arora R, Vatner DE,
Vatner SF (2003) Is treating cardiac hypertrophy salutary or
detrimental: the two faces of Janus. Am J Physiol Heart Circ
Physiol 284:H1043–H1047
39. Kotlo K, Johnson KR, Grillon JM, Geenen DL, Detombe P,
Danziger RS (2012) Phosphoprotein abundance changes in
hypertensive cardiac remodeling. J Proteomics 21(77):1–13
40. Feldman AM, Weinberg EO, Ray PE, Lorell BH (1993)
Selective changes in cardiac gene expression during compen-
sated hypertrophy and the transition to cardiac decompensation
in rats with chronic aortic banding. Circ Res 73:184–192
41. Weber KT, Brilla CG (1991) Pathological hypertrophy and
cardiac interstitium. Fibrosis and renin-angiotensin-aldosterone
system. Circulation 83:1849–1865
42. Cantley LC (2002) The phosphoinositide 3-kinase pathway.
Science 296(5573):1655–1657
43. Matsui T, Li L, Wu JC, Cook SA, Nagoshi T, Picard MH et al
(2002) Phenotypic spectrum caused by transgenic overexpression
of activated Akt in the heart. J Biol Chem 277(25):22896–22901
44. Massague J (1990) The transforming growth factor-beta family.
Annu Rev Cell Biol 6:597–641
45. Hasenfuss G, Pieske B (2002) Calcium cycling in congestive
heart failure. J Mol Cell Cardiol 34(8):951–969
46. Frantz S, Behr T, Hu K, Fraccarollo D, Strotmann J, Goldberg E
et al (2007) Role of p38 mitogen-activated protein kinase in
cardiac remodelling. Br J Pharmacol 150(2):130–135
47. Moschella PC, Rao VU, McDermott PJ, Kuppuswamy D (2007)
Regulation of mTOR and S6K1 activation by the nPKC iso-
forms, PKCepsilon and PKCdelta, in adult cardiac muscle cells.
J Mol Cell Cardiol 43(6):754–766
48. Gupta RC, Mishra S, Rastogi S, Imai M, Habib O, Sabbah HN
(2003) Cardiac SR-coupled PP1 activity and expression are
increased and inhibitor 1 protein expression is decreased in failing
607 hearts. Am J Physiol Heart Circ Physiol 285(6):H2373–H2381
49. van Oort RJ, van RE, Bourajjaj M, Schimmel J, Jansen MA, van
der NR, et al (2006) MEF2 activates a genetic program pro-
moting chamber dilation and contractile dysfunction in 621
calcineurin-induced heart failure. Circulation 114(4):298–308
50. Crabtree GR (2001) Calcium, calcineurin, and the control of
transcription. J Biol Chem 276:2313–2316
51. Haywood GA, Gullestad L, Katsuya T, Hutchinson HG, Pratt RE,
Horiuchi M et al (1997) AT1 and AT2 angiotensin receptor gene
expression in human heart failure. Circulation 95(5):1201–1206
52. Haq S, Choukroun G, Lim H, Tymitz KM, del Monte F,
Gwathmey J et al (2001) Differential activation of signal
transduction pathways in human hearts with hypertrophy versus
advanced heart failure. Circulation 103(5):670–677
53. AbdAlla S, Lother H, el Massiery A, Quitterer U (2001) Increased
AT(1) receptor heterodimers in preeclampsia mediate enhanced
angiotensin II responsiveness. Nat Med Sep 7(9):1003–1009
54. Molkentin JD, Lu JR, Antos CL, Markham B, Richardson J,
Robbins J, Grant SR, Olson EN (1998) A calcineurin-dependent
transcriptional pathway for cardiac hypertrophy. Cell 93:
215–228
55. Valente AJ, Clark RA, Siddesha JM, Siebenlist U, Chandrasekar
B (2012) CIKS (Act1 or TRAF3IP2) mediates angiotensin-II-
induced interleukin-18 expression, and Nox2-dependent car-
diomyocyte hypertrophy. J Mol Cell Cardiol 53(1):113–124
56. Zhang ZY, Liu XH, Hu WC, Rong F, Wu XD (2010) The cal-
cineurin-myocyte enhancer factor 2c pathway mediates cardiac
hypertrophy induced by endoplasmic reticulum stress in neo-
natal rat cardiomyocytes. Am J Physiol Heart Circ Physiol
298:H1499–H1509
57. Dode L, Wuytack F, Kools PF, Baba-Aissa F, Raeymaekers L,
Brike F et al (1996) cDNA cloning, expression and chromo-
somal localization of the human sarco/endoplasmic reticulum
Ca2?-ATPase 3 gene. Biochem J 318(Pt 2):689–699
58. Kirby MS, Sagara Y, Gaa S, Inesi G, Lederer WJ, Rogers TB
(1992) Thapsigargin inhibits contraction and Ca2? transient in
cardiac cells by specific inhibition of the sarcoplasmic reticulum
Ca2? pump. J Biol Chem 267(18):12545–12551
59. Bers DM, Eisner DA, Valdivia HH (2003) Sarcoplasmic retic-
ulum Ca2? and heart failure: roles of diastolic leak and Ca2?
transport. Circ Res 93(6):487–490
60. Zheng M, Dilly K, Dos Santos Cruz J, Li M, Gu Y, Ursitti JA
et al (2004) Sarcoplasmic reticulum calcium defect in Ras-
induced hypertrophic cardiomyopathy heart. Am J Physiol Heart
Circ Physiol 286(1):H424–433
61. Meyer M, Schillinger W, Pieske B, Holubarsch C, Heilmann C,
Posival H et al (1995) Alterations of sarcoplasmic reticulum
proteins in failing human dilated cardiomyopathy. Circulation
92(4):778–784
Heart Fail Rev
123
62. Hasenfuss G, Meyer M, Schillinger W, Preuss M, Pieske B, Just
H (1997) Calcium handling proteins in the failing human heart.
Basic Res Cardiol 92(Suppl 1):87–93
63. Hasenfuss G, Schillinger W, Lehnart SE, Preuss M, Pieske B,
Maier LS et al (1999) Relationship between Na?–Ca2?
exchanger protein levels and diastolic function of failing human
myocardium. Circulation 99(5):641–648
64. Houser SR, Piacentino V, Weisser J (2000) Abnormalities of
calcium cycling in the hypertrophied and failing heart. J Mol
Cell Cardiol 32(9):1595–1607
65. Movsesian MA, Karimi M, Green K, Jones LR (1994) Ca2?-
transporting ATPase, phospholamban, and calsequestrin levels
in nonfailing and failing human myocardium. Circulation
90(2):653–657
66. Schmidt U, Hajjar RJ, Helm PA, Kim CS, Doye AA, Gwathmey
JK (1998) Contribution of abnormal sarcoplasmic reticulum
ATPase activity to systolic and diastolic dysfunction in human
heart failure. J Mol Cell Cardiol 30(10):1929–1937
67. Schwinger RHG, Bohm M, Schmidt U, Karczewski P, Baven-
diek U, Flesch M et al (1995) Unchanged protein levels of
SERCA II and phospholamban but reduced Ca2? uptake and
Ca2?-ATPase activity of cardiac sarcoplasmic reticulum from
dilated cardiomyopathy patients compared with patients with
nonfailing hearts. Circulation 92(11):3220–3228
68. Dhalla NS, Golfman L, Liu X, Sasaki H, Elimban V, Rupp H (1999)
Subcellular remodeling and heart dysfunction in cardiac hypertro-
phy due to pressure overload. Ann N Y Acad Sci 874(1):100–110
69. Bassani JW, Qi M, Samarel AM, Bers DM (1994) Contractile
arrest increases sarcoplasmic reticulum calcium uptake and
SERCA2 gene expression in cultured neonatal rat heart cells.
Circ Res 74(5):991–997
70. Ait Mou Y, Reboul C, Andre L, Lacampagne A, Cazorla O
(2009) Late exercise training improves non-uniformity of
transmural myocardial function in rats with ischaemic heart
failure. Cardiovasc Res 81(3):555–564
71. Buttrick PM, Kaplan M, Leinwand LA, Scheuer J (1994) Altera-
tions in gene expression in the rat heart after chronic pathological
and physiological loads. J Mol Cell Cardiol 26(1):61–67
72. Tada M, Kirchberger MA, Repke DI, Katz AM (1974) The
stimulation of calcium transport in cardiac sarcoplasmic retic-
ulum by adenosine 3’:5’-monophosphate-dependent protein
kinase. J Biol Chem 249(19):6174–6180
73. Napolitano R, Vittone L, Mundina C, Chiappe de Cingolani G,
Mattiazzi A (1992) Phosphorylation of phospholamban in the
intact heart. A study on the physiological role of the Ca2?-
calmodulin-dependent protein kinase system. J Mol Cell Cardiol
24(4):387–396
74. Kuschel M, Karczewski P, Hempel P, Schlegel WP, Krause EG,
Bartel S (1999) Ser16 prevails over Thr17 phospholamban
phosphorylation in the beta-adrenergic regulation of cardiac
relaxation. Am J Physiol 276(5 Pt 2):H1625–H1633
75. Collins HL, Loka AM, DiCarlo SE (2005) Daily exercise-
induced cardioprotection is associated with changes in calcium
regulatory proteins in hypertensive rats. Am J Physiol Heart Circ
Physiol 288(2):H532–H540
76. Sugizaki MM, Leopoldo AP, Conde SJ, Campos DS, Damato R,
Leopoldo AS et al (2011) Upregulation of mRNA myocardium
calcium handling in rats submitted to exercise and food
restriction. Arq Bras Cardiol 97(1):46–52
77. Yin CC, Lai FA (2000) Intrinsic lattice formation by the ryanodine
receptor calcium-release channel. Nat Cell Biol 2(9):669–671
78. Medeiros A, Rolim NP, Oliveira RS, Rosa KT, Mattos KC,
Casarini DE et al (2008) Exercise training delays cardiac dys-
function and prevents calcium handling abnormalities in sym-
pathetic hyperactivity-induced heart failure mice. J Appl Physiol
104(1):103–109
79. Bhupathy P, Babu GJ, Periasamy M (2007) Sarcolipin and
phospholamban as regulators of cardiac sarcoplasmic reticulum
Ca2? ATPase. J Mol Cell Cardiol 42:903–911
80. Periasamy M, Bhupathy P, Babu GJ (2008) Regulation of sar-
coplasmic reticulum Ca2? ATPase pump expression and its
relevance to cardiac muscle physiology and pathology. Cardio-
vasc Res 77:265–273
81. Teucher N, Prestle J, Seidler T, Currie S, Elliott EB, Reynolds
DF et al (2004) Excessive sarcoplasmic/endoplasmic reticulum
Ca2?-ATPase expression causes increased sarcoplasmic reticu-
lum Ca2? uptake but decreases myocyte shortening. Circulation
110:3553–3559
82. Vangheluwe P, Tjwa M, Van Den Bergh A, Louch WE, Beul-
lens M, Dode L et al (2006) SERCA2 pump with an increased
Ca2? affinity can lead to severe cardiac hypertrophy, stress
intolerance and reduced life span. J Mol Cell Cardiol 41:
308–317
83. Vangheluwe P, Sipido KR, Raeymaekers L, Wuytack F (2006)
New perspectives on the role of SERCA20s Ca2? affinity in
cardiac function. Biochim Biophys Acta 1763:1216–1228
84. Kadambi VJ, Ponniah S, Harrer JM, Hoit BD, Dorn GW, Walsh
RA et al (1996) Cardiac-specific overexpression of phospho-
lamban alters calcium kinetics and resultant cardiomyocyte
mechanics in transgenic mice. J Clin Invest 97(2):533–539
85. Schmitt JP, Kamisago M, Asahi M, Li GH, Ahmad F, Mende U
et al (2003) Dilated cardiomyopathy and heart failure caused by
a mutation in phospholamban. Science 299(5611):1410–1413
86. Haghighi K, Kolokathis F, Gramolini AO, Waggoner JR, Pater
L, Lynch RA et al (2006) A mutation in the human phospho-
lamban gene, deleting arginine 14, results in lethal, hereditary
cardiomyopathy. Proc Natl Acad Sci USA 103(5):1388–1393
87. Asahi M, Otsu K, Nakayama H, Hikoso S, Takeda T, Gramolini
AO et al (2004) Cardiac-specific overexpression of sarcolipin
inhibits sarco(endo) plasmic reticulum Ca2?ATPase (SER-
CA2a) activity and impairs cardiac function in mice. Proc Natl
Acad Sci USA 101(25):9199–9204
88. Babu GJ, Bhupathy P, Timofeyev V, Petrashevskaya NN, Reiser
PJ, Chiamvimonvat N et al (2007) Ablation of sarcolipin
enhances sarcoplasmic reticulum calcium transport and atrial
contractility. Proc Natl Acad Sci USA 104:17867–17872
89. Kawase Y, Hajjar RJ (2008) The cardiac sarcoplasmic/endo-
plasmic reticulum calcium ATPase: a potent target for cardio-
vascular diseases. Nat Clin Pract Cardiovasc Med 5:554–565
90. Gramolini AO, Trivieri MG, Oudit GY, Kislinger T, Li W, Patel
MM et al (2006) Cardiac-specific overexpression of sarcolipin in
phospholamban null mice impairs myocyte function that is restored
by phosphorylation. Proc Natl Acad Sci USA 103(7):2446–2451
91. Shanmugam M, Gao S, Hong C, Fefelova N, Nowycky MC, Xie
L-H, Periasamy M, Babu GJ (2011) Ablation of phospholamban
and sarcolipin results in cardiac hypertrophy and decreased
cardiac contractility. Cardiovasc Res 89:353–361
92. MacLennan DH, Wong PT (1971) Isolation of a calcium-
sequestering protein from sarcoplasmic reticulum. Proc Natl
Acad Sci USA 68(6):1231–1235
93. Terentyev D, Viatchenko-Karpinski S, Gyorke I, Volpe P,
Williams SC, Gyorke S (2003) Calsequestrin determines the
functional size and stability of cardiac intracellular calcium
stores: mechanism for hereditary arrhythmia. Proc Natl Acad Sci
USA 100(20):11759–11764
94. Zhang L, Kelley J, Schmeisser G, Kobayashi YM, Jones LR
(1997) Complex formation between junctin, triadin, calsequestrin,
and the ryanodine receptor. J Biol Chem 272(37):23389–23397
95. Qin J, Valle G, Nani A, Nori A, Rizzi N, Priori SG et al (2008)
Luminal Ca2? regulation of single cardiac ryanodine receptors:
insights provided by calsequestrin and its mutants. J Gen Physiol
131(4):325–334
Heart Fail Rev
123
96. Gyorke S, Terentyev D (2008) Modulation of ryanodine
receptor by luminal calcium and accessory proteins in health and
cardiac disease. Cardiovasc Res 77(2):245–255
97. Kucerova D, Baba HA, Boknik P, Fabritz L, Heinick A, Matus
M, Muller FU, Neumann J, Schmitz W, Kirchhefer U (2012)
Modulation of SR Ca2? release by the triadin-calsequestrin ratio
in ventricular myocytes. Am J Physiol Heart Circ Physiol 15;
302(10):H2008–H2017
98. Kubalova Z, Gyorke I, Terentyeva R, Viatchenko-Karpinski S,
Terentyev D, Williams SC et al (2004) Modulation of cyto-
solic and intra-sarcoplasmic reticulum calcium waves by cal-
sequestrin in rat cardiac myocytes. J Physiol 561(Pt 2):
515–524
99. Hu ST, Liu GS, Shen YF, Wang YL, Tang Y, Yang YJ (2011)
Defective Ca2? handling proteins regulation during heart failure.
Physiol Res 60(1):27–37
100. Wu X, Bers DM (2006) Sarcoplasmic reticulum and nuclear
envelope are one highly interconnected Ca2? store throughout
cardiac myocyte. Circ Res 99:283–291
101. McFarland TP, Milstein ML, Cala SE (2010) Rough endoplasmic
reticulum to junctional sarcoplasmic reticulum trafficking of cal-
sequestrin in adult cardiomyocytes. J Mol Cell Cardiol 49:556–564
102. Kiarash A, Kelly CE, Phinney BS, Valdivia HH, Abrams J, Cala
SE (2004) Cardiovasc Res 63:264–272
103. Guo A, Cala SE, Song LS (2012) Calsequestrin accumulation in
rough endoplasmic reticulum promotes perinuclear Ca2?
release. J Biol Chem 287(20):16670–16680
104. Fleischer S, Ogunbunmi EM, Dixon MC, Fleer EA (1985)
Localization of Ca2? release channels with ryanodine in junc-
tional terminal cisternae of sarcoplasmic reticulum of fast
skeletal muscle. Proc Natl Acad Sci USA 82(21):7256–7259
105. Inui M, Saito A, Fleischer S (1987) Purification of the ryanodine
receptor and identity with feet structures of junctional terminal
cisternae of sarcoplasmic reticulum from fast skeletal muscle.
J Biol Chem 262(4):1740–1747
106. Inui M, Saito A, Fleischer S (1987) Isolation of the ryanodine
receptor from cardiac sarcoplasmic reticulum and identity with
the feet structures. J Biol Chem 262(32):15637–15642
107. Meissner G (1994) Ryanodine receptor/Ca2? release channels
and their regulation by endogenous effectors. Annu Rev Physiol
56:485–508
108. Takeshima H, Nishimura S, Matsumoto T, Ishida H, Kangawa
K, Minamino N et al (1989) Primary structure and expression
from complementary DNA of skeletal muscle ryanodine
receptor. Nature 339(6224):439–445
109. Tunwell RE, Wickenden C, Bertrand BM, Shevchenko VI, Walsh
MB, Allen PD et al (1996) The human cardiac muscle ryanodine
receptor-calcium release channel: identification, primary struc-
ture and topological analysis. Biochem J 318(Pt 2):477–487
110. Xiao B, Sutherland C, Walsh MP, Chen SR (2004) Protein kinase
A phosphorylation at serine-2808 of the cardiac Ca2?-release
channel (ryanodine receptor) does not dissociate 12.6-kDa
FK506-binding protein (FKBP12.6). Circ Res 94(4):487–495
111. Rodriguez P, Bhogal MS, Colyer J (2003) Stoichiometric
phosphorylation of cardiac ryanodine receptor on serine 2809 by
calmodulin-dependent kinase II and protein kinase A. J Biol
Chem 278(40):38593–38600
112. Fruen BR, Bardy JM, Byrem TM, Strasburg GM, Louis CF
(2000) Differential Ca2? sensitivity of skeletal and cardiac
muscle ryanodine receptors in the presence of calmodulin. Am J
Physiol 279:C724–C733
113. Yamaguchi N, Xu L, Pasek DA, Evans KE, Meissner G (2003)
Molecular basis of calmodulin binding to cardiac Ca2? release
channel (ryanodine receptor). J Biol Chem 278:23480–23486
114. Yano M, Kobayashi S, Kohno M, Doi M, Tokuhisa T, Okuda S,
et al (2003) FKBP12.6-mediated stabilization of calcium-release
channel (ryanodine receptor) as a novel therapeutic strategy
against heart failure. Circulation 107(3):477–484
115. Lehnart SE, Wehrens XH, Reiken S, Warrier S, Belevych AE,
Harvey RD et al (2005) Phosphodiesterase 4D deficiency in the
ryanodine-receptor complex promotes heart failure and
arrhythmias. Cell 123(1):25–35
116. Marx SO, Reiken S, Hisamatsu Y, Jayaraman T, Burkhoff D,
Rosemblit N et al (2000) PKA phosphorylation dissociates
FKBP12.6 from the calcium release channel (ryanodine recep-
tor): defective regulation in failing hearts. Cell 101(4):365–376
117. Reiken S, Lacampagne A, Zhou H, Kherani A, Lehnart SE,
Ward C et al (2003) PKA phosphorylation activates the calcium
release channel (ryanodine receptor) in skeletal muscle: defec-
tive regulation in heart failure. J Cell Biol 160(6):919–928
118. Zou Y, Liang Y, Gong H, Zhou N, Ma H, Guan A, Sun A, Wang P,
Niu Y, Jiang H, Takano H, Toko H, Yao A, Takeshima H, Akazawa
H, Shiojima I, Wang Y, Komuro I, Ge J (2011) Ryanodine recep-
tor type 2 is required for the development of pressure overload
induced cardiac hypertrophy. Hypertension 58(6):1099–1110
119. Gangopadhyay JP, Ikemoto N (2011) Aberrant interaction of
calmodulin with the ryanodine receptor develops hypertrophy in
the neonatal cardiomyocyte. Biochem J 1; 438(2):379–387
120. Meissner G, Henderson JS (1987) Rapid calcium release from
cardiac sarcoplasmic reticulum vesicles is dependent on Ca2?
and is modulated by Mg2 ? , adenine nucleotide, and calmod-
ulin. J Biol Chem 262:3065–3073
121. Fruen BR, Bardy JM, Byrem TM, Strasburg GM, Louis CF
(2000) Differential Ca2? sensitivity of skeletal and cardiac
muscle ryanodine receptors in the presence of calmodulin. Am J
Physiol Cell Physiol 279(3):C724–C733
122. Yamaguchi N, Takahashi N, Xu L, Smithies O, Meissner G
(2007) Early cardiac hypertrophy in mice with impaired cal-
modulin regulation of cardiac muscle Ca2? release channel.
J Clin Invest 117:1344–1353
123. Fatt P, Katz B (1953) The electrical properties of crustacean
muscle fibres. J Physiol 120(1–2):171–204
124. Hagiwara S, Ozawa S, Sand O (1975) Voltage clamp analysis of
two inward current mechanisms in the egg cell membrane of a
starfish. J Gen Physiol 65(5):617–644
125. Leszek P, Szperl M, Klisiewicz A, Janas J, Rozanski J, Rywik T,
Piotrowski W, Kopacz M, Korewicki J (2008) Alterations in
calcium regulatory protein expression in patients with preserved
left ventricle systolic function and mitral valve stenosis. J Card
Fail 14(10):873–880
126. Richard S, Perrier E, Fauconnier J, Perrier R, Pereira L, Gomez
AM et al (2006) Ca2?-induced Ca2? entry or how the L-type
Ca2? channel remodels its own signalling pathway in cardiac
cells. Prog Biophys Mol Biol 90:118–135
127. Bers DM, Despa S (2006) Cardiac myocytes Ca2? and Na? regu-
lation in normal and failing hearts. J Pharmacol Sci 100(5):315–322
128. Hussain M, Orchard CH (1997) Sarcoplasmic reticulum Ca2?
content, L-type Ca2? current and the Ca2? transient in rat
myocytes during beta-adrenergic stimulation. J Physiol 505(Pt
2):385–402
129. DelPrincipe F, Egger M, Pignier C, Niggli E (2001) Enhanced
E–C coupling efficiency after beta-stimulation of cardiac myo-
cytes. Biophys J 80:64a
130. Goonasekera SA, Hammer K, Auger-Messier M, Bodi I, Chen
X, Zhang H, Reiken S, Elrod JW, Correll RN, York AJ, Sargent
MA, Hofmann F, Moosmang S, Marks AR, Houser SR, Bers
DM, Molkentin JD (2012) Decreased cardiac L-type Ca2?
channel activity induces hypertrophy and heart failure in mice.
J Clin Invest 3;122(1):280–290
131. Piot C, Lemaire S, Albat B, Seguin J, Nargeot J, Richard S
(1996) High frequency-induced upregulation of human cardiac
calcium currents. Circulation 93(1):120–128
Heart Fail Rev
123
132. Makarewich CA, Correll RN, Gao H, Zhang H, Yang B,
Berretta RM, Rizzo V, Molkentin JD, Houser SR (2012) A
caveolae-targeted L-type Ca2 ? channel antagonist inhibits
hypertrophic signaling without reducing cardiac contractility.
Circ Res 110(5):669–674
133. Philipson KD, Longoni S, Ward R (1988) Purification of the
cardiac Na?/Ca2? exchange protein. Biochimica et Biophysica
Acta (BBA) Biomembranes 945(2):298–306
134. Nicoll DA, Longoni S, Philipson KD (1990) Molecular cloning
and functional expression of the cardiac sarcolemmal Na?–Ca2?
exchanger. Science 250(4980):562–565
135. Li Z, Matsuoka S, Hryshko LV, Nicoll DA, Bersohn MM, Burke EP
et al (1994) Cloning of the NCX2 isoform of the plasma membrane
Na?–Ca2? exchanger. J Biol Chem 269(26):17434–17439
136. Nicoll DA, Quednau BD, Qui Z, Xia YR, Lusis AJ, Philipson
KD (1996) Cloning of a third mammalian Na?–Ca2? exchanger,
NCX3. J Biol Chem 271(40):24914–24921
137. Nicoll DA, Ottolia M, Lu L, Lu Y, Philipson KD (1999) A new
topological model of the cardiac sarcolemmal Na?–Ca2?
exchanger. J Biol Chem 274(2):910–917
138. Kent RL, Rozich JD, McCollam PL et al (1993) Rapid expres-
sion of the Na?–Ca2? exchanger in response to cardiac pressure
overload. Am J Physiol 265:H1024–H1029
139. Menick DR, Barnes KV, Thacker UF et al (1996) The exchanger
and cardiac hypertrophy. Ann N Y Acad Sci 779:489–501
140. Menick DR, Renaud L, Buchholz A, Muller JG, Zhou H,
Kappler CS et al (2007) Regulation of Ncx1 gene expression in
the normal and hypertrophic heart. Ann N Y Acad Sci 1099:
195–203
141. Xu L, Renaud L, Muller JG, Baicu CF, Bonnema DD, Zhou H
et al (2006) Regulation of Ncx1 expression. Identification of
regulatory elements mediating cardiac-specific expression and
up-regulation. J Biol Chem 281(45):34430–34440
142. Seth M, Sumbilla C, Mullen SP, Lewis D, Klein MG, Hussain A
et al (2004) Sarco(endo)plasmic reticulum Ca2? ATPase
(SERCA) gene silencing and remodeling of the Ca2? signaling
mechanism in cardiac myocytes. Proc Natl Acad Sci USA
101(47):16683–16688
143. Kent RL, Rozich JD, McCollam PL, McDermott DE, Thacker
UF, Menick DR et al (1993) Rapid expression of the Na?-Ca2?
exchanger in response to cardiac pressure overload. Am J
Physiol 265(3 Pt 2):H1024–H1029
144. Cheng G, Hagen TP, Dawson ML, Barnes KV, Menick DR
(1999) The role of GATA, CArG, E-box, and a novel element in
the regulation of cardiac expression of the Na?–Ca2? exchanger
gene. J Biol Chem 274(18):12819–12826
145. Muller JG, Isomatsu Y, Koushik SV, O’Quinn M, Xu L, Kappler
CS et al (2002) Cardiac-specific expression and hypertrophic
upregulation of the feline Na?-Ca2? exchanger gene H1-pro-
moter in a transgenic mouse model. Circ Res 90(2):158–164
146. Lu YM, Huang J, Shioda N, Fukunaga K, Shirasaki Y, Li XM
et al (2011) CaMKIIdeltaB mediates aberrant NCX1 expression
and the imbalance of NCX1/SERCA in transverse aortic con-
striction-induced failing heart. PLoS ONE 6(9):e24724
147. Xu L, Chen J, Li XY, Ren S, Huang CX, Wu G, Li XY, Jiang XJ
(2012) Analysis of Na?/Ca2? exchanger (NCX) function and
current in murine cardiac myocytes during heart failure. Mol
Biol Rep 39(4):3847–3852
148. Lu L, Mei DF, Gu AG, Wang S, Lentzner B, Gutstein DE et al
(2002) Exercise training normalizes altered calcium-handling
proteins during development of heart failure. J Appl Physiol
92(4):1524–1530
149. Cheung JY, Song J, Rothblum LI, Zhang XQ (2004) Exercise
training improves cardiac function postinfarction: special
emphasis on recent controversies on Na?/Ca2? exchanger. Exerc
Sport Sci Rev 32(3):83–89
150. Litwin S, Bridge JH (1997) Enhanced Na?/Ca2? exchange in
the infracted heart. Implications for excitation–contraction
coupling. Circ Res 81:1083–1093
151. Pogwizd SM, Qi M, Yuan W, Samarel AM, Bers DM (1999)
Upregulation of Na_/Ca2_ exchanger expression and function in
an arrhythmogenic rabbit model of heart failure. Circ Res
85:1009–1019
152. Hasenfuss G (1998) Alteration of calcium-regulatory proteins in
heart failure. Cardiovasc Res 37:279–289
153. de Tombe PP (1998) Altered contractile function in heart failure.
Cardiovasc Res 37:367–380
154. Dipla K, Mattiello J, Margulies K, Jeevanandam V, Houser S
(1999) Sarcoplasmic reticulum and the Na?/Ca2? exchanger
both contribute to the Ca2? transient of failing human ventric-
ular myocytes. Circ Res 84:435–444
155. Gaughan J, Furukawa S, Jeevanadam V, Hefner C, Kubo H,
Margulies K, McGowan B, Mattiello J, Dipla K, Piacentino V
III, Li S, Houser S (1999) Sodium/calcium exchange contributes
to contraction and relaxation in failed human ventricular myo-
cytes. Am J Physiol Heart Circ Physiol 277:H714–H724
156. Oliveira RS, Ferreira JC, Gomes ER, Paixao NA, Rolim NP,
Medeiros A et al (2009) Cardiac anti-remodelling effect of
aerobic training is associated with a reduction in the calcineurin/
NFAT signalling pathway in heart failure mice. J Physiol 587(Pt
15):3899–3910
157. Kemi OJ, Ceci M, Wisloff U, Grimaldi S, Gallo P, Smith GL
et al (2008) Activation or inactivation of cardiac Akt/mTOR
signaling diverges physiological from pathological hypertrophy.
J Cell Physiol 214(2):316–321
158. Emter CA, McCune SA, Sparagna GC, Radin MJ, Moore RL
(2005) Low-intensity exercise training delays onset of decom-
pensated heart failure in spontaneously hypertensive heart fail-
ure rats. Am J Physiol Heart Circ Physiol 289(5):H2030–H2038
159. Davey Smith G, Shipley MJ, Batty GD, et al (2000) Physical
activity and cause-specific mortality in the Whitehall study.
Public Health 114:308–315
160. Manson JE, Hu FB, Rich-Edwards JW et al (1999) A prospec-
tive study of walking as compared with vigorous exercise in the
prevention of coronary heart disease in women. N Engl J Med
341:650–658
161. Lee IM, Sesso HD, Oguma Y et al (2003) Relative intensity of
physical activity and risk of coronary heart disease. Circulation
107:1110–1116
162. Tanasescu M, Leitzmann MF, Rimm EB et al (2002) Exercise
type and intensity in relation to coronary heart disease in men.
JAMA 288:1994–2000
163. Leon AS, Myers MJ, Connett J (1997) Leisure time physical
activity and the 16-year risks of mortality from coronary heart
disease and all-causes in the Multiple Risk Factor Intervention
Trial (MRFIT). Int J Sports Med 18:S208–S215
164. Hamer M, Chida Y (2012) Walking and primary prevention. A
metaanalysis of prospective cohort studies. Br J Sports Med
165. Haskell WL, Lee IM, Pate RR, Powell KE, Blair SN, Franklin
BA, Macera CA, Heath GW, Thompson PD, Bauman A (2007)
Physical activity and public health: updated recommendation for
adults from the American College of Sports Medicine and the
American Heart Association. Med Sci Sports Exerc 39(8):
1423–1434
166. Hamer M, Stamatakis E (2008) Physical activity and cardio-
vascular disease: directions for future research. Open Sports Sci
J 1, 1–2 1 1875-399X/08 2008
167. Wannamethee SG, Shaper AG, Walker M (2000) Physical
activity and mortality in older men with diagnosed coronary
heart disease. Circulation 102:1358–1363
168. Wisløff U, Støylen A, Loennechen JP et al (2007) Superior
cardiovascular effect of aerobic interval training versus
Heart Fail Rev
123
moderate continuous training in heart failure patients: a ran-
domized study. Circulation 115:3086–3094
169. Peschel T, Sixt S, Beitz F et al (2007) High, but not moderate
frequency and duration of exercise training induces downregu-
lation of the expression of inflammatory and atherogenic adhe-
sion molecules. Eur J Cardiovasc Prev Rehabil 14:476–482
170. Ferreira JC, Moreira JB, Campos JC, Pereira MG, Mattos KC,
Coelho MA, Brum PC (2011) Angiotensin receptor blockade
improves the net balance of cardiac Ca2? handling-related
proteins in sympathetic hyperactivity-induced heart failure. Life
Sci 88(13–14):578–585
171. Yeh YH, Wakili R, Qi XY, Chartier D, Boknik P, Kaab S,
Ravens U, Coutu P, Dobrev D, Nattel S (2008) Calcium-han-
dling abnormalities underlying atrial arrhythmogenesis and
contractile dysfunction in dogs with congestive heart failure.
Circ Arrhythm Electrophysiol 1(2):93–102
172. Winslow RL, Rice J, Jafri S, Marban E, O’Rourke B (1999)
Mechanisms of altered excitation–contraction coupling in
canine tachycardia-induced heart failure, II: model studies. Circ
Res 84(5):571–586
173. Armoundas AA, Rose J, Aggarwal R, Stuyvers BD, O’rourke B,
Kass DA, Marban E, Shorofsky SR, Tomaselli GF, William
Balke C (2007) Cellular and molecular determinants of altered
Ca2? handling in the failing rabbit heart: primary defects in SR
Ca2? uptake and release mechanisms. Am J Physiol Heart Circ
Physiol 292(3):H1607–H1618
174. Currie S, Smith GL (1999) Enhanced phosphorylation of
phospholamban and downregulation of sarco/endoplasmic
reticulum Ca2? ATPase type 2 (SERCA 2) in cardiac sarco-
plasmic reticulum from rabbits with heart failure. Cardiovasc
Res 41(1):135–146
175. Roos KP, Jordan MC, Fishbein MC, Ritter MR, Friedlander M,
Chang HC, Rahgozar P, Han T, Garcia AJ, Maclellan WR,
Ross RS, Philipson KD (2007) Hypertrophy and heart failure in
mice overexpressing the cardiac sodium-calcium exchanger.
J Card Fail 13(4):318–329
176. Schotten U, Koenigs B, Rueppel M, Schoendube F, Boknik P,
Schmitz W, Hanrath P (1999) Reduced myocardial sarcoplasmic
reticulum Ca2?-ATPase protein expression in compensated
primary and secondary human cardiac hypertrophy. J Mol Cell
Cardiol 31(8):1483–1494
177. Jones LR, Suzuki YJ, Wang W, Kobayashi YM, Ramesh V,
Franzini-Armstrong C, Cleemann L, Morad M (1998) Regula-
tion of Ca2? signaling in transgenic mouse cardiac myocytes
overexpressing calsequestrin. J Clin Invest 101(7):1385–1393
178. da Costa Rebelo RM, Schreckenberg R, Schluter KD (2012)
Adverse cardiac remodelling in spontaneously hypertensive rats:
acceleration by high aerobic exercise intensity. J Physiol 590(Pt
21):5389–5400
179. Bernardo BC, Weeks KL, Pretorius L, McMullen JR (2010)
Molecular distinction between physiological and pathological
cardiac hypertrophy: experimental findings and therapeutic
strategies. Pharmacol Ther 128(1):191–227
180. Lygren B, Tasken K (2006) Compartmentalized cAMP signal-
ling is important in the regulation of Ca2? cycling in the heart.
Biochem Soc Trans 34(Pt 4):489–491
181. Gyorke S, Terentyev D (2008) Modulation of ryanodine
receptor by luminal calcium and accessory proteins in health and
cardiac disease. Cardiovasc Res 77:245–255
182. Kamp TJ, Hell JW (2000) Regulation of cardiac L-type calcium
channels by protein kinase A and protein kinase C. Circ Res
87(12):1095–1102
183. Lytton J (2007) Na?/Ca2? exchangers: three mammalian gene
families control Ca2? transport. Biochem J 406(3):365–382
Heart Fail Rev
123