1 biological nanomotors and their associated motor proteins l. a. reuter winona state university...

1

Biological NanoMotors and Their Associated Motor Proteins

L. A. ReuterWinona State University

Please Note: Much of the graphic material within this PowerPoint presentation came from the reading assignment of “The World of the Cell, sixth edition”, authored by Becker, Kleinsmith & Hardin and published by Pearson-Benjamin Cummings.

Find the links to this PowerPoint on the web:http://bio.winona.edu/Nano427/Secure/MP/MotorProteins.ppt

(protected site: enter winona\username & password for authentication)

http://bio.winona.edu/Nano427/Secure/MP/MotorProteins.ppt

2

• Definitions• What is a motor protein

• General Review of Motor proteins• Contraction / Depolymerizarion motors• Expansion / Polymerization motors• Sliding filament motors

– Actin– Myosin– Tubulin

• Walking motor proteins– Dynein– Kinesin

• Focus on Bacterial Flagella• Rotating flagella • Structure of bacterial flagella• Relation of bacterial flagella to pili• Relation of bacterial flagella to secretory systems• Synthesis of bacterial flagella

• Discussion• Possible uses in nanotechnology

Outline

3

Definitions:

• Motor:

Anything that produces or imparts motion.

• Biological Motor

A motor that is created through life’s processes and which operates as a part of a living being.

4

Debatable Biological Motors:

• Hexokinase – an enzyme that moves

• Na+ – K+ ATPase – a transmembrane pump that moves ions across lipid bilayers

• Other I: Nano – GroEL GroES Chaperone

Nano – Holliday Junction

• Other II: Micro – Brownian Motion

• Other III: Pico – Molecular Motion Pico – Facilitated Diffusion of Water (~5 x 109 H2O/sec)

(Motor: Anything that produces or imparts motion.)

5

Fundamental Motor Protein Principles:

• Proteins change their shape when they bind ligands or other molecules.

• Change of protein shape may drive displacement of other objects.

6

Contraction / Depolymerizarion motors:

• Collagen – an extracellular structural protein

– Echinoderm connective tissue shortens– Tendons shorten after they are stretched– Extracellular matrix contracts when fibroblasts “mov

e”

• Microtubules – (MT are really nanotubules!) – MT shorten during mitotic anaphase

http://www.biolbull.org/cgi/content/full/206/1/4

8

Figure 17-1 Different Kinds of

Extracellular Matrix

Scanning EM picture of loose connective tissue:

FibroblastsCollagen fibersElastic FibersRed Blood CellGAGs

9

Loose connective tissue

10

Dense Regular Connective Tissue

11

Figure 17-2 The Structure of Collagen

Protein is high in amounts of: Glycine Hydroxylysine Hydroxyproline

Glycine is in the axis of the triple helix, the only aa small enough to fit there

Tension strength of a 1 mm diameter fiber is ~9 kg.67 nm repeat distance of cross striationsStretch < 5% breaking

12

Figure 17-3 Collagen Assembly

270 to 300 nm long,1.5 nm diameter

67 nm repeat distance, ~270 molecules x-sec

After action of procollagen peptidase

13

Collagen is formed in a

fibroblast groove.

14

Table 17-2 Types of Collagens, Their Occurrence, and Their Structure

Vertebrates have ~25 different kinds of α-chains, each with its own gene and expressed differently in different tissues >15 types of collagen molecules.

Type I collagen accounts for ~90% of collagen in human body.

15

Figure 15-3 A Model for Microtubule Assembly In Vitro

16

Figure 15-2 Microtubule Structure

α,β-Heterodimer: microtubule has direction

17

Figure 15-4 The Kinetics of Microtubule Assembly In Vitro

Initiation / nucleation is slower than elongation

Critical concentration

18

Figure 15-5 Polar Assembly of Microtubules In VitroBasal body (an MTOC) nucleates assembly of microtubules from both ends

Plus end grows faster than minus end

Critical concentration for the plus end is lower than that for minus end

Treadmilling is possible

19

Figure 15-6 Treadmilling of MicrotubulesCritical concentration of heterodimers = concentration at which rate of polymerization = rate of depolymerization

20

Figure 15-7 The GTP Cap and Its Role in the Dynamic Instability of Microtubules

GTP and Mg++ are required for polymerization

Each heterodimer binds two GTP

Hydrolysis of GTP is not needed for assembly

Interactions between GDP heterodimers is too weak to allow polymerization

GTP hydrolysis to GDP gives rise to dynamic instability

21

Figure 15-8 The Dynamic Instability of Microtubules In Vivo

Chapter: 15

Movie:clspimt.mov

Description: Interphase microtubule dynamics. Visualize the dynamic instability of microtubules in a living cell. These images of the lamella of a migrating newt epithelial cell were taken using fluorescence microscopy and rhodamine-labelled tubulin. Notice the alternate lengthening and shortening of individual microtubules as the lamella of the migrating cell moves forward. Courtesy of Edward Salmon.

28 minutes63μ x 63μ

22

Plus and minus ends grow and shrink independently

Microtubule Catastrophe = switch from growth phase to shrinkage phase

Microtubule Rescue = switch from shrinkage phase to growth phase

Figure 15-7 The GTP Cap and Its Role in the Dynamic Instability of Microtubules

23

Animal Mitosis

• Chapter: 19• Movie: 12-05-AnimalMitosisVideo-S.mov• Description: Mitosis. Follow the process of

mitosis in living animal cells. This dividing cell was imaged using differential interference contrast microscopy. Notice how the chromosomes condense and become visible in prophase, line up at the cell equator in metaphase, and separate into two equal sets in anaphase, just before nuclear membrane reformation at telophase and cell division via cytokinesis.

24

Mitotic Spindle Formation

• Chapter: 19• Movie: fig4.mov• Description: Spindle formation during

mitosis. Watch how microtubules assemble to form the spindle fibers during prophase of mitosis. These time-lapse images of cells expressing a green fluorescent protein-tubulin fusion were taken using confocal microscopy. Notice how the centrosomes at the opposite ends of the cell act as nucleation sites for the growing microtubules. Courtesy of Ronald Vale.

25

Anaphase

• Chapter: 19• Movie: fig4a.anaphase_mitosis.avi• Description: Microtubules in anaphase.

Watch how microtubules function during anaphase of mitosis in living cells. These Drosophila S2 cultured cells are expressing a green fluorescent protein-tubulin fusion. Notice the dynamic movement of the microtubules as the spindle poles move apart. Courtesy of Ronald Vale.

http://fig4a.anaphase_mitosis.avi/

26

Microtubules during Anaphase• Chapter: 4• Movie: DeAna1-

medium.mov• Description: Microtubules

in anaphase See a dividing sand dollar embryo stained to visualize microtubules during its first cleavage. Images are a series of confocal sections spaced 0.5 microns apart through a fixed embryo. Notice how the microtubules radiate from the microtubule-organizing centers. Courtesy of George von Dassow.

27

Figure 19-1 The Eukaryotic Cell Cycle

28

Figure 19-20 The Phases of Mitosis in an Animal Cell

29

Figure 19-22 Attachment of Chromosomes to the Mitotic Spindle

30

Figure 19-24 The Two Types of Movement

Involved in Chromosome Separation During

Anaphase

Kinetochore microtubules shorten

Axial microtubules lengthen

31

Figure 19-44 The Use of Laser Photobleaching to Study Chromosome Movement During Mitosis

37

Cytokinesis• Chapter: 19• Movie: cleavmov.qt• Description: Cleavage of a

fertilized egg. Watch as a fertilized frog egg undergoes multiple rounds of mitosis and cytokinesis. Each round of cell division parcels the original cytoplasm into smaller and smaller cells. Notice how the cell divisions appear to be synchronized. Courtesy of Dr Huw Williams and Professor Jim Smith.

http://cleavmov.qt.mov/

38

Actin-Myosin in Cytokinesis

• Chapter: 19• Movie: myosin_cyto.mov• Description: Myosin and cytokinesis. See

how nonmuscle myosin functions in cytokinesis. These HeLa cultured cells were photographed during cytokinesis using differential interference contrast microscopy. Notice how myosin interacts with a tightening ring of microfilaments called the contractile ring to drive the closure of the ring and divide the cytoplasm between the two daughter cells. Courtesy of Aaron Straight.

39

Actin-Myosin in Phagocytosis

• Chapter: 12• Movie: dictyo.mov• Description: Phagocytosis in action. Watch as one

cell is consumed by another cell in the process known as phagocytosis. In this video, a yeast cell (red) is being consumed by a larger cell of Dictyostelium, which is expressing a fusion of green fluorescent protein with coronin, an actin-associated protein involved in phagocytosis. Notice the expression of the coronin protein fusion where the Dictyostelium cytoplasm is surrounding the yeast cell. Courtesy of Guenther Gerisch Max-Planck-Institut für Biochemie.

40

Chemotaxis Demonstration

• Chapter: 16• Movie: ax3single.mov• Description: Demonstration of chemotaxis. See

how a single-celled amoeba moves in response to a chemical attractant. This Dictyostelium cell is showing positive chemotaxis as it moves toward a micropipette tip containing cAMP. Notice how the cell extends a pseudopod to change direction toward the cAMP in response to the movement of the pipette. Courtesy of Susan Lee and Rick Firtel, Section of Cell and Developmental Biology, University of California, San Diego.

41

Chemotaxis of a Neutrophil

• Movie: polariz2.mov• Description: Chemotaxis of a neutrophil.

Watch a neutrophil move toward a chemical attractant supplied in a glass micropipette. Neutrophils are white blood cells involved in defense against pathogens that respond to chemical signals via G-protein-linked receptors. They are attracted to sites of injured tissue where pathogens may be found. Notice how the cell forms an actin-based protrusion in the direction of the chemoattractant. Courtesy of Henry Bourne.

42

Lamellipodia in Cell Migration

• Chapter: 16• Movie: fishlamellipodia.mov• Description: Lamellipodia in cell migration.

Watch how a cell is able to move using projections known as lamellipodia. These images of a migrating fish epidermal cell were taken using differential interference contrast microscopy. Notice how the lamellipodium forms a thin sheet at the forward edge of the cell, attaches to the substrate, and then pulls the cell forward. Courtesy of Mark S. Cooper.

43

Figure 16-25 The Steps of Cell Crawling

44

Figure 16-25 The Steps of Cell Crawling

45

Figure 15-15 The Architecture of Actin in Crawling Cells

46

CAMs – Cytoskeleton - Movement

• Chapter: 16 • Movie: MOT15S.MOV• Description: Regulation of axon movement. See

how cell adhesion molecules (CAMs) are important in guiding the movement of neuronal axons. This animation shows how these CAMs interact with the cytoskeleton in response to contact with other cells or surfaces. Notice how small membrane vesicles containing the adhesion molecules are transported to the leading edge of the cell to aid in translocation of the cell. Courtesy of GENERALASAHI Co.,Ltd. GA Digital Graphics and Hiroyuki Kamiguchi, Laboratory for Neuronal Growth Mechanisms, RIKEN Brain Science Institute.

47

Figure 15-13 A Model for Microfilament Assembly In Vitro

F-actin (filamentous)

Directional

G-actin (globular)

48

Figure 15-19 Interrelationships Between the Main Structural Form of Actin

49

Figure 15-20 Microvillus Structure

50

Figure 15-21 The Terminal Web of an Intestinal

Epithelial Cell

51

Figure 15-16 Deep-Etch Electron

Micrograph Showing Actin Bundles in

Filopodia

52

F-Actin Knot Tying

• Chapter: ApH• Movie: TieFA.mov• Description: Tying a molecular knot. Watch a

remarkable video showing how a then undergraduate student Yasuharu Arai used "optical tweezers" to tie a knot in an F-actin microfilament. To do this, polystyrene beads are attached to each end of the microfilament and then held in an optical trap produced by a laser beam. Notice how one end of the microfilament is held motionless, while the other is manipulated to form the molecular knot. From http://www.f.waseda.jp/kazuhiko. Courtesy of K. Kinosita, Jr. Arai, Y. et al., Nature 399, 466-468 (1999).

53

Figure 15A-1 Infection of a Macrophage by Listeria monocytogenes

Listeria can move by polymerizing host actin

54

Listeria Polymerize Host Cytoplasmic Actin for Movement Listeria monocytogenes: take two

• Motility • Curiously, although Listeria are actively motile by means of

peritrichous flagella at room temperature (20-25 degrees), the organisms do not synthesize flagella at body temperatures (37 degrees). Instead, virulence is associated with another type of motility: the ability of the bacteria to move themselves into, within and between host cells by polymerization of host cell actin at one end of the bacterium ("growing actin tails") that can propel the bacteria through cytoplasm. However, one should not totally dismiss the advantage of flagellar motility for existence and spread of the bacteria outside of the immediate host environment

• As in the case of Vibrio cholerae, wherein movement, attachment and penetration of the intestinal mucosa are determinants of infection (if not disease), this was thought to be the situation with Listeria, which is also acquired by ingestion and must also find a way to attach to the intestinal mucosa. With cholera, the actively-motile vibrios are thought to use their flagella to swim against the peristaltic movement of the bowel content and to penetrate (by swimming laterally) the mucosal lining of the gut where they adhere.

55

Figure 16-9 Myosin Family Members

56

Figure 15-14 Using Myosin S1 Subfragments to Determine Actin Polarity

36 nm repeat

57

Figure 16-10 Levels of Organization of Skeletal Muscle Tissue

58

Figure 16-11 Arrangement of Thick and Thin Filaments in a

Myofibril

59

Figure 16-12 Appearance of

and Nomenclature

for Skeletal Muscle

60

Figure 16-13 The Thick

Filament of Skeletal Muscle

61

Figure 16-14 The Thin Filament of Striated Muscle

62

Figure 16-15 Structural Proteins of the Sarcomere

63

Table 16-2 Major Protein Compounds of Vertebrate Skeletal Muscle

64

Figure 16-16 The Sliding-Filament Model of Muscle Contraction

65

Figure 16-17 Cross-Bridges

66

Figure 16-20 The Sacroplasmic Reticulum and

the Transverse Tubule System of Skeletal Muscle

Cells

67

Figure 16-21 Stimulation of a Muscle Cell by a Nerve Impulse

68


69


70

Figure 16-19 Regulation of Contraction in

Striated Muscle

71

Figure 16-18 The Cyclic Process of

Muscle Contraction

72

Figure 16-22 Cardiac Muscle Cells

73

Cardiac Muscle Contraction

• Chapter: 16• Movie: cardio_movie2.mov• Description: Calcium-stimulated muscle contraction.

Watch the contraction of a heart muscle cell in response to pulses of calcium. This chick embryonic cardiomyocyte is expressing a fusion of green fluorescent protein and myosin. Notice how the repeated contraction of the muscle cell can be monitored by observing the spacing of adjacent Z lines. Copyright 2003 The Company of Biologists Ltd. J Cell Sci Wang et al. 116 (20): 4227.

74

Figure 16-23 Smooth Muscle and Its

Contraction

75

Figure 16-24 Phosphorylation of Smooth Muscle and Nonmuscle Myosin

76


Myosin Light Chain Kinase

77

Figure 16-24 Phosphorylation

of Smooth Muscle and Nonmuscle

Myosin

78


79

Actin Moves Along Fixed Myosin

• Chapter: 16• Movie: cell_motility1.mov• Description: Motility in a cell-free system. See how

actin and myosin interact to generate movement, even when isolated from the cell. In this assay, fluorescently-labeled actin filaments were added to a microscope slide coated with purified myosin. Notice how, following the addition of ATP at the beginning of the video, the purified actin filaments are able to move along the immobilized myosin molecules. Courtesy of James Spudich.

80

Myosin-Actin Interaction

• Chapter: 16• Movie: ActScal2.mov• Description: Myosin-actin interaction. See

the conformational changes of myosin interacting with an actin microfilament. This animation shows an atomic model of the globular head of myosin II while it is docked onto a binding site on the microfilament. Notice the two different conformations the myosin molecule can assume, representing the start and the end of the power stroke. Courtesy of John Trinick, Molecular Contractility Group, Leeds University.

82

Figure 19-27 Mitotic Motors

83


84


85

Isolated Flagellum Beating

• Chapter: 16• Movie: 18µMflagellumbeats.mov• Description: Motion of isolated flagellum. See how

a flagellum beats in the presence of ATP even when separated from the cell. The flagellum of one of these bull sperm cells was cut in half using a glass microprobe. Notice how the excised piece of the flagellum continues to beat in the absence of any connection to the original cell. Dana L. Holcomb-Wygle, Kathleen A. Lesich, and Charles B.

• Lindemann. Oakland University, Department of Biological Sciences, Rochester, Michigan 48309

86

Mouse Sperm Secondary Waves

• Chapter: 16• Movie: SecondaryW.mov• Description: Flagellum movement in swimming

sperm. See the complex motion of the flagellum of an immobilized mouse sperm. These images were taken using dark-field microscopy, with the recorded image inverted to show the cell as dark against a light background. As the flagellum undulates, notice the presence of smaller secondary waves superimposed upon the large back-and-forth primary waves. Courtesy of Geraint Vernon.

87

Figure 16-6 Cilia and Flagella

88

Coordinated Ciliary Motion

• Chapter: 16• Movie: metachrony.mpg• Description: Ciliary motion. See the

movement of cilia on living cells. Cilia are short hair-like projections used for locomotion or for feeding in protozoa, or for clearing of particles from respiratory airways in animals. They are similar to flagella but much more numerous, often completely covering a cell. Notice the coordinated beating of waves of cilia on the cell in this video. Courtesy of Michael Sanderson.

89


90


91


92

Figure 16-7 The Structure of Cilium

93


94


95


96

Figure 16-8 Enlarged Views of an Axoneme

97


98


99

Flagellum Sliding Filament

• Chapter: 16• Movie: B14frames.mov• Description: Microtubule sliding in flagellum

movement. Observe the sliding of microtubule doublets that is responsible for the movement of a sperm cell flagellum. Tiny gold beads (40 nm diameter) were attached to opposite sides of this flagellum and ATP was added to stimulate movement. Notice how the beads move relative to each other, demonstrating the microtubule sliding action that causes the flagellum to bend. Animation courtesy of Charles J. Brokaw, California Institute of Technology. Details of this type of experiment were published in Brokaw, C. J., J. Cell Biol. 114: 1201-1215 (1991).

102

Organelles Move Along Microtubules

• Chapter: 16• Movie: otmovie.mov• Description: Movement of organelles in vivo. Watch

as organelles are transported along microtubules in an axon of a neuron. This cell of Aplysia, a marine snail used in neurobiology research, was photographed using high-resolution differential interference contrast microscopy. Notice how organelles are moving in opposite directions on different microtubule tracks. Courtesy of Paul Forscher, Department of Molecular, Cellular, and Developmental Biology, Yale University.

103

Elodea Cyclosis

• Chapter: 11• Movie: Elodea_Cyclosis.mov• Description: Chloroplast movement. Watch

the movement of chloroplasts in a live aquatic plant cell. This video shows cells of Elodea, a fresh-water plant commonly used in home aquariums. Notice how many chloroplasts are present in each cell and how they move around the cell, enabling the plant to take advantage of differing light conditions.

104

ER to Golgi Vesicle Movement

• Chapter: 12• Movie: uobf1.mov• Description: ER to Golgi traffic. Watch glycoprotein

movement through the secretory pathway of living cells. Green fluorescent protein was fused to a protein destined for secretion in order to visualize its movement from the ER into the Golgi complex at the center of this cell. Notice how the protein fusion moves in a stop-and-go fashion into the Golgi, where it undergoes final processing prior to secretion. Courtesy of Jennifer Lippincott-Schwartz.

105

GFP-KDEL

• Chapter: 4, 12• Movie: ER2.avi• Description: Protein targeting to the

endoplasmic reticulum using GFP-KDEL. Visualize ER-localized gene expression in a tobacco leaf epidermal cell. A protein fusion of green fluorescent protein, an ER signal sequence, and the four-amino-acid KDEL ER retention sequence is targeted and expressed in the ER lumen. Courtesy of Chris Hawes and Petra Boevink.

106

Moving ER Vesicles

• Chapter: 4• Movie: ichida2.mov• Description: ER and Mitochondria in leaf

cells See images from living tobacco leaf cells showing the movement of the ER (green) and mitochondria (red). Video frames were taken every 2 seconds over a period of 3 minutes, 22 seconds. Notice how dynamic the cell cytoplasm is in these live cells. Courtesy of Barbara Pickard and Audrey Ichida.

107

Melanin Transport Along Microtubules

• Chapter: 16• Movie: MT_melanophor.mov• Description: Transport along microtubules. Watch

the movement of granules containing the dark pigment melanin as they travel along microtubules in a fish epidermal cell. This movement of melanin granules enables the fish to change its color to avoid predators. Rhodamine-labeled tubulin was used to visualize the microtubules. Notice how some of the microtubules appear to move as tubulin monomers are added to one end and removed from the other. Courtesy of Gary G. Borisy.

108

Movement of Organelles

• Chapter: 16• Movie: DissAxo.mov• Description: Movement of organelles in vitro.

Watch as organelles are transported along microtubules isolated from the giant axon of a squid cell. These images were made using video-enhanced differential interference contrast microscopy. Notice how, once ATP is added, organelle movement is observed even when the microtubules are outside the cell cytoplasm. Courtesy of Ronald Vale.

109

Table 16-1 Selected Motor Proteins of Eukaryotic Cells

110

Figure 16-1 Deep-Etch Electron

Micrograph Showing a

Vesicle Attached to a

Microtubule in a Crayfish Axon

111

Figure 16-2 Microtubule-Based

Motility

112

Figure 16-3 Movement of

Kinesin

113

Figure 16-4 Schematic

Representation of the Cytoplasmic Dynein/Dynactin

Complex

114

Figure 16-5 Microtubules, Motor MAPs, and the Golgi Complex: A

Model

117

Figure 10-15 The Flow of Electrons Through Respiratory Complexes I, III, and IV with

Concomitant Directional Proton Pumping

43P 11P13P

118

Figure 10-18 F1 and F0 Components of the Bacterial F0F1ATP Synthase

119

ATP Synthetase (Top View) ATP Synthetase (Side View)

• Chapter: 10• Movie: F1_top_sp_2.mov• Description: ATP synthase 3D structure.

Watch a top view of the conformational changes in the ATPase F1 complex during one 360° rotation of the stalk. The three subunits are shown in yellow, the three subunits in red+green, and the stalk in blue+grey. Notice how each rotation consists of three successive 120° movements of the stalk, causing large domain shifts in the and subunits. Courtesy of George Oster and Hongyun Wang.

120

Figure 20-20 The Cellular Apparatus for Bacterial Conjugation

121

Salmonella

1974 rotary motor

10 x 10,000 nm

20,000 rpm

10-16 wattsproton motive force

80% efficiency

~30 flagellar proteins, several to 10s of K

122

The End(for this evening)

123

Gliding

• Gliding motion in Bacteria

124

Figure 20-20 The Cellular Apparatus for Bacterial Conjugation

125

Figure 20-21 DNA Transfer by Bacterial Conjugation

126

Chromatium

• A motile, purple, sulphur bacterium.

127

Rhodospirillum rubrum

• A motile, purple, non-sulphur, bacterium.

129

Neuron Growth Cone Actin and Tubulin

• Chapter: 4, 15, A• Movie: movinggceffect.mov• Description: The cytoskeleton in a neuron

growth cone. See the localization of actin and tubulin in a neuron growth cone of Aplysia, a marine snail used in neural development research. The video shows a differential interference contrast (DIC) image, followed by images of staining for F-actin (red) and tubulin (green). Notice the highly organized structure of different regions of the cell cytoskeleton. Courtesy of Paul Forscher.

130

Actin in Lamellipodium

• Chapter: 15• Movie: kerat.mov• Description: Actin network in crawling cells.

See the actin microfilament network in the lamellipodium of a Xenopus keratocyte that was cultured on a glass coverslip. The video shows the cell in motion, followed by electron microscopy to visualize the extensive actin network present in the lamellipodium. Notice the extensive branching of the actin network (highlighted in yellow). Courtesy of Gary Borisy.

131

GFP Marker in Mice

• Chapter: 20• Movie: okabe1.mov• Description: GFP-expressing transgenic mice. See

transgenic mice produced by introducing the gene encoding green fluorescent protein (GFP) under the control of an actin promoter. These mice express GFP in all tissues where actin is normally expressed and glow green when exposed to blue or UV light, making them useful for studies of cell fate in cell transplantation experiments. Notice how not all pups in this litter are expressing the transgene. Courtesy of Masaru Okabe.

132

Pronuclear Injection

• Chapter: 20• Movie: PNI.mov• Description: Pronuclear injection. Watch an early

step in the production of transgenic mice. In this video, a microscopic glass needle containing DNA is inserted into the pronucleus of a fertilized mouse oocyte that is held in place by suction against a micropipette at the left edge of the video. Following integration of the introduced DNA into the host cell chromosome, the transgenic embryonic cell will be implanted into a female foster mouse. Courtesy of Ronald Naumann.

133

G Protein Heterotrimer

• Chapter: 14• Movie: Heterotrimer_G_Prote#1DB7D9.avi• Description: Heterotrimeric G protein

structure. See the conformational changes induced in a heterotrimeric G protein following GTP binding and hydrolysis. The GTPase domain of the G subunit is shown in green. Notice how the G subunit dissociates from the G and the G subunits following GTP binding. Provided by Cameron Slayden.

134

Ca++-ATPase

• Chapter: 8• Movie: Ca-ATPase-surface-motion.mpg• Description: Ca-ATPase cycle. Watch the

conformational changes induced in the membrane-bound Ca-ATPase during one cycle of calcium binding, phosphorylation, and calcium release. Binding of calcium ions causes a conformational change, exposing a phosphorylation site. Phosphorylation by ATP causes a further conformational change resulting in calcium release on the other side of the membrane. Courtesy of Mark B. Gerstein.

135

Mitosis and Nondisjunction

• Chapter: 19• Movie: nondisjun.mov• Description: Nondisjunction in mitosis. See what

happens when mitosis malfunctions. Newt epithelial cells were grown on cover slips and photographed using differential interference contrast microscopy. Notice how, in this cell, one chromosome (black arrow) never arrives at the equatorial plate, likely due to improper attachment to the spindle fiber. As in meiotic nondisjunction, this will result in the daughter cells having abnormal numbers of chromosomes. Time-lapse sequence by Dr. Conly L. Rieder, Wadsworth Center, Albany, New York 12201-0509.

137

Figure 15-17 Branched Actin Networks and the Arp2/3 Complex

138

Figure 15-17 Branched Actin Networks and the Arp2/3 Complex

139

Figure 14-23 The Stimulation of G Protein-Linked Signal Transduction Pathways by - and -Adrenergic Receptors

140

Figure 14-24 Stimulation of Glycogen Breakdown by Epinephrine

141

Figure 14-18 Signal Transduction Through Receptor Tyrosine Kinases

142

Table 14-2 Examples of Growth Factor Families

143

Figure 15-1 The Intracellular Distribution of Microtubules, Microfilaments, and Intermediate Filaments

144


145


146

Table 15-1 Properties of Microtubules, Microfilaments, and Intermediate Filaments

147

Table 15-2 Techniques for Studying the Cytoskeleton

Drugs: Colchicine; nocodazol; taxol; cytochalasin D, B; lantrunculin; phalloidin (inhibit polymerization / inhibit depolymerization)

148

Figure 15-9 The Centrosome

149

Figure 15-10 -Tubulin at the Base of Microtubules Originating from the Centrosome

150

Figure 15-11 The Effects of Microtubule Polarity on MT Orientation in Animal Cells

151

Figure 15-18 Regulation of Protrusions by Small G Proteins

152

Figure 15-22 Support of the Erythrocyte Plasma Membrane

by a Spectrin-Ankyrin-Actin

Network

153

Figure 15-23 Intermediate Filaments

154

Table 15-3 Classes of Intermediate Filaments

155

Figure 15-24 Structural Similarities of Intermediate Filament Proteins

156

Figure 15-25 A Model for

Intermediate Filament

Assembly In Vitro

157

Figure 15-26 Connections Between Intermediate Filaments and Other Components of the Cytoskeleton

158

Figure 16A-1 Scanning Electron

Micrograph of Epithelial Cells of

the Inner Ear Showing Several

Rows of Stereocilia

159

Figure 16-26 Scanning Electron

Micrograph of a Mouse Fibroblast

Showing Numerous Filopodia Extending

from the Cell Surface

160

Figure 16-27 Attachment Coupled to Protrusion

Formation in a Migrating Cell

161

Figure 16-28 Overall Distribution of Myosin

II and Actin in a Fibroblast

162

Figure 16-29 Amoeboid Movement

163

Figure 16-29 Amoeboid Movement

164

Figure 17A-1 Bacterial Pathogens and Cell Adhesion Proteins

165

Figure 17-1 Different Kinds of Extracellular Matrix

166



167



168

Table 17-1 Extracellular Structures of Eukaryotic Cells

169

Figure 17-4 Stretching and

Recoiling of Elastin Fibers

170

Figure 22-16 A Model for the

Signal Mechanism of

Cotranslational Import

171

Figure 22-17 Cotranslational

Insertion of Transmembrane Proteins into the

ER Membrane

172

Figure 22-18 Main Polypeptide Transport Complexes of the Outer and Inner Membranes of Mitochondria and Chloroplasts

173

Figure 22-19 Experimental

Demonstration That Polypeptides Span Both

Mitochondrial Membranes During Import

174

Figure 22-20 Posttranslational Import

of Polypeptides into the Mitochondrion

175

Figure 22-21 The Structure of Puromycin

176

Figure 22-2 Important

Binding Sites of the Prokaryotic

Ribosome

177

Figure 21-11 A Closeup of the Prokaryotic Elongation Complex

178

Figure 21-12 Termination of

Transcription in Prokaryotic Genes

That Do Not Require the Rho

Termination Factor

179

Figure 19-28 Cytokinesis in an Animal Cell

180

Figure 19-29 Cytokinesis and Cell Plate Formation in a Plant Cell

181

Figure 19-30 Cleavage of a

Fertilized Egg into Progressively

Smaller Cells

182

Figure 19-41 Growth Factor Signaling via the

Ras Pathway

183

Figure 19-42 The PI3K-Akt Signaling Pathway

184

Figure 19-25 Microtubule Polarity in the Mitotic Spindle

185

Figure 19-21 The Phases of Mitosis in a Plant Cell

186

Figure 19-26 Kinetochores and Their Microtubules

1 biological nanomotors and their associated motor proteins l. a. reuter winona state university...

Documents

biological motora motor

j cell

cell body

associated motor proteins

extracellular matrix

fibroblast shortenschapter

fibroblast g

effect of fibroblast