Effect of G protein lipid modifications on G protein membrane interactions

Download Effect of G protein lipid modifications on G protein membrane interactions

Post on 15-Jul-2016

234 views

Category:

Documents

22 download

Embed Size (px)

TRANSCRIPT

<ul><li><p>S26 Abstracts / Chemistry and Physics of Lipids 149S (2007) S23S49</p><p>the membrane lipid composition, it must be connectedto the remainder of the protein via a flexible molec-ular hinge that allows transmembrane domain VII toreside in the membrane in the normal mode and exitto the peripmode. Theextra-memmembranetopology isthe transloproteinlipogy is neceof lipids onproper topolipids withlipids, regasupport up</p><p>AcknowGM20478.</p><p>doi:10.101</p><p>PO 7Effect ofprotein mPablo V. ELlado, Silv</p><p>MolecularBiomedicinBalearic Is</p><p>G proteinsreceptors (agonist binup to threepalmitate aG proteinthe numbemembraneregulate thin turn regteins, we hproteinmetified thelamellar anabsence ofFor this pu(G), dimmembraneconcentratithe aboveby centrif</p><p>immunoblotting. We have observed that these lipidsinduced relevant changes in the structural properties ofmembranes and in the interaction of G proteins to mem-branes. The main effects were induced by isoprenyl</p><p>ties (gh incctionof PE aneasesand tctivelitic acubunit</p><p>prot</p><p>0.101</p><p>ngescytosbran</p><p>oxidamila Fshcha</p><p>anuelemy oll, Ru</p><p>y memstresscompxidanhenyle ba</p><p>ichfd fattyity and. Oure rang</p><p>tionalch ascmeas</p><p>-anglePR-spthermfferend out tn homtural sroteinnels alasmic side of the membrane in the invertedrefore, the net charge of the cytoplasmicbrane surface and the charge character of thelipid headgroups determine topology. Finalestablished after the N-terminal bundle exits</p><p>con and is therefore primarily determined byid interactions. Although near normal topol-ssary for uphill transport activity, the effectstopology and function are not coupled. Whilelogy requires balancing of anionic lipids bynet zero charge, only non-bilayer-forming</p><p>rdless of their different chemical character,hill transport activity.ledgement: Supported by NIH grant</p><p>6/j.chemphyslip.2007.06.054</p><p>G protein lipid modications on Gembrane interactions</p><p>scriba, Jesus Casas, Rafael Alvarez, Victoriaia Teres</p><p>Celle/Biology-IUNICS/University of thelands, Spain</p><p>are in molar excess over G protein-coupledGPCR) to enable signal amplification uponding. Each G protein heterotrimer can bearsimultaneous lipid modifications (myristate,nd isoprenyl residues), which contribute tomembrane interactions. In GPCR clusters,r of G protein lipids inserted in the plasmacould be very high. Because these lipids cane physical properties of membranes, whichulate the interaction and activity of G pro-ave studied the effect of these lipids on Gmbrane interactions. Thus, we have quan-</p><p>binding of G proteins to membranes withd nonlamellar propensity in the presence ormyristate, palmitate or isoprenyl moieties.</p><p>rpose, we used purified G protein monomersers (G) and trimers (G) and models (liposomes) formed with PC and variousons of PE in the absence or presence oflipids. G protein binding was determined</p><p>ugation analysis, followed by quantitative</p><p>moiewhic(redutureof G(incrmers</p><p>respepalmG sand G</p><p>doi:1</p><p>PO 8ChaandmemantiLiudGolo1 EmAcadof CeMantivelipidantiooxypas thAOsurateactivtivelya widfuncEhrliwere</p><p>rightby ETheby difoundatiostructal pchaneranyl-geraniol), present in the G protein,reased nonlamellar (HII) phase propensityin 12 C in the L-to-HII transition tempera-), concomitant with increases in the bindingd G to nonlamellar-prone membranes</p><p>of about 60 and 120% in the binding of dim-rimers to PC:PE 6:4, mol:mol, membranes,y). These results suggest that myristic andid are not as relevant as isoprenyl moieties ofs in the regulation of the membrane structureein interaction with membranes.</p><p>6/j.chemphyslip.2007.06.055</p><p>in structural state of the lipid phasekeletal proteins of cellulares under the action of hybridntsatkullina 1, Olga Vekshina 1, Alexanderpov 1, Elena Burlakova 1, Yuri Kim 2</p><p>Institute of Biochemical Physics, Russianf Sciences, Russia; 2 Institute of Biophysicsssian Academy of Sciences, Russiabrane pathologies are characterized by oxida-and significant changes in structural state,osition and functioning of membranes. Thet (AO) phenozan [-4-oxy(3,5-ditertbutyl-4-)potassium propionate] was used at IBCPsic compound in the synthesis of hybridans by addition of choline residue and sat-acid tail to enhance the anticholinesteraseto increase the rigidity of membranes respec-main aim was to study the effect of AO ine of concentrations on certain structural and</p><p>parameters of membranes of erythrocytes anditic carcinoma cells in vitro. The ionic flowsured potentiometrically with recording oflight scattering; the viscosity of membranes,ectroscopy using paramagnetic spin probes.ograms of erythrocyte shades were analyzedtial adiabatic scanning microcalorimetry. Wehat the changes in the system of lipid peroxi-eostasis in membranes result in changes of thetate of lipids (microviscosity) and cytoskele-s, followed by functional shifts of Ca2+K+nd changes of cell reactions. These results</p></li></ul>