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Titolo:
Local control models of cardiac excitation-contraction coupling - A possible role for allosteric interactions between ryanodine receptors
Autore:
Stern, MD; Song, LS; Cheng, HP; Sham, JSK; Yang, HT; Boheler, KR; Rios, E;
Indirizzi:
NIA, Cardiovasc Sci Lab, NIH, Baltimore, MD 21224 USA NIA Baltimore MD USA 21224 rdiovasc Sci Lab, NIH, Baltimore, MD 21224 USA Johns Hopkins Med Inst, Div Pulm & Crit Care Med, Baltimore, MD 21224 USA Johns Hopkins Med Inst Baltimore MD USA 21224 ed, Baltimore, MD 21224 USA Rush Univ, Sch Med, Chicago, IL 60612 USA Rush Univ Chicago IL USA 60612Rush Univ, Sch Med, Chicago, IL 60612 USA
Titolo Testata:
JOURNAL OF GENERAL PHYSIOLOGY
fascicolo: 3, volume: 113, anno: 1999,
pagine: 469 - 489
SICI:
0022-1295(199903)113:3<469:LCMOCE>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
CALCIUM-RELEASE CHANNEL; FROG SKELETAL-MUSCLE; SARCOPLASMIC-RETICULUM; CA2+-RELEASE CHANNELS; CA2+ CHANNELS; HEART-MUSCLE; RAT-HEART; INACTIVATION; ADAPTATION; ACTIVATION;
Keywords:
sarcoplasmic reticulum; Monte Carlo; calcium-induced calcium release; dihydropyridine receptor; diad junction;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
48
Recensione:
Indirizzi per estratti:
Indirizzo: Stern, MD NIA, Cardiovasc Sci Lab, NIH, 5600 Nathan Shock Dr, Baltimore, MD 21224 USA NIA 5600 Nathan Shock Dr Baltimore MD USA 21224 re, MD 21224 USA
Citazione:
M.D. Stern et al., "Local control models of cardiac excitation-contraction coupling - A possible role for allosteric interactions between ryanodine receptors", J GEN PHYSL, 113(3), 1999, pp. 469-489

Abstract

In cardiac muscle, release of activator calcium from the sarcoplasmic reticulum occurs by calcium-induced calcium release through ryanodine receptors(RyRs),which are clustered in a dense, regular, two-dimensional lattice array at the diad junction. We simulated numerically the stochastic dynamics of RyRs and L-type sarcolemmal calcium channels interacting via calcium nano-domains in the junctional cleft. Four putative RyR gating schemes based on single-channel measurements in lipid bilayers all failed to give stable excitation-contraction coupling, due either to insufficiently strong inactivation to terminate locally regenerative calcium-induced calcium release or insufficient cooperativity to discriminate against RyR activation by background calcium. If the ryanodine receptor was represented, instead, by a phenomenological four-state gating scheme, with channel opening resulting from simultaneous binding of two Ca2+ ions, and either calcium-dependent or activation-linked inactivation, the simulations gave a good semiquantitative accounting for the macroscopic features of excitation-con traction coupling. It was possible to restore stability to a model based on a bilayer-derived gating scheme, by introducing allosteric interactions between nearest-neighbor RyRs so as to stabilize the inactivated state and produce cooperativityamong calcium binding sites on different RyRs. Such allosteric coupling between RyRs may be a function of the foot process and lattice array, explaining their conservation during evolution.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 03/07/20 alle ore 00:53:02