2 MECHANISMS OF QUANTIZED CALCIUM-RELEASE IN SKELETAL-MUSCLE

Citation
Mg. Klein et al., 2 MECHANISMS OF QUANTIZED CALCIUM-RELEASE IN SKELETAL-MUSCLE, Nature, 379(6564), 1996, pp. 455-458
Citations number
31
Categorie Soggetti
Multidisciplinary Sciences
Journal title
NatureACNP
ISSN journal
00280836
Volume
379
Issue
6564
Year of publication
1996
Pages
455 - 458
Database
ISI
SICI code
0028-0836(1996)379:6564<455:2MOQCI>2.0.ZU;2-I
Abstract
SKELETAL muscle uses voltage sensors in the transverse tubular membran e(1-3) that are linked by protein-protein interactions(4-6) to intrace llular ryanodine receptors(7-10), which gate the release of calcium fr om the sarcoplasmic reticulum. Here we show, by using voltage-clamped single fibres and confocal imaging, that sto chastic calcium-release e vents, visualized as Ca2+ sparks, occur in skeletal muscle and origina te at the tried. Unitary triadic Ca2+-release events are initiated by the voltage sensor in a steeply voltage-dependent manner, or occur spo ntaneously by a mechanism independent of the voltage sensor. Large amp litude events also occur during depolarization and consist of two or m ore unitary events. We propose a 'dual-control' model for discrete Ca2 + release events from the sacroplasmic reticulum that unifies diverse observations about Ca2+-signalling in frog skeletal muscle, and that m ay be applicable to other excitable cells.