Ca2+ signalling between single L-type Ca2+ channels and ryanodine receptors in heart cells

Citation
Sq. Wang et al., Ca2+ signalling between single L-type Ca2+ channels and ryanodine receptors in heart cells, NATURE, 410(6828), 2001, pp. 592-596
Citations number
29
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Multidisciplinary,Multidisciplinary,Multidisciplinary
Journal title
NATURE
ISSN journal
0028-0836 → ACNP
Volume
410
Issue
6828
Year of publication
2001
Pages
592 - 596
Database
ISI
SICI code
0028-0836(20010329)410:6828<592:CSBSLC>2.0.ZU;2-6
Abstract
Ca2+-induced Ca2+ release is a general mechanism that most cells use to amp lify Ca2+ signals(1-5). In heart cells, this mechanism is operated between voltage-gated L-type Ca2+ channels (LCCs) in the plasma membrane and Ca2+ r elease channels, commonly known as ryanodine receptors, in the sarcoplasmic reticulum(3-5) The Ca2+ influx through LCCs traverses a deft of roughly 12 nm formed by the cell surface and the sarcoplasmic reticulum membrane, and activates adjacent ryanodine receptors to release Ca2+ in the form of Ca2 sparks(6). Here we determine the kinetics, fidelity and stoichiometry of c oupling between LCCs and ryanodine receptors. We show that the local Ca2+ s ignal produced by a single opening of an LCC named a 'Ca2+ sparklet: can tr igger about 4-6 ryanodine receptors to generate a Ca2+ spark. The coupling between LCCs and ryanodine receptors is stochastic, as judged by the expone ntial distribution of the coupling latency. The fraction of sparklets that successfully triggers a spark is less than unity and declines in a use-depe ndent manner. This optical analysis of single-channel communication affords a powerful means for elucidating Ca2+-signalling mechanisms at the molecul ar level.