Ca 2+ signaling amplification by oligomerization of L-type Ca v 1.2 channels
Open Access
- 17 January 2012
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 109 (5), 1749-1754
- https://doi.org/10.1073/pnas.1116731109
Abstract
Ca2+ influx via L-type Cav1.2 channels is essential for multiple physiological processes, including gene expression, excitability, and contraction. Amplification of the Ca2+ signals produced by the opening of these channels is a hallmark of many intracellular signaling cascades, including excitation-contraction coupling in heart. Using optogenetic approaches, we discovered that Cav1.2 channels form clusters of varied sizes in ventricular myocytes. Physical interaction between these channels via their C-tails renders them capable of coordinating their gating, thereby amplifying Ca2+ influx and excitation-contraction coupling. Light-induced fusion of WT Cav1.2 channels with Cav1.2 channels carrying a gain-of-function mutation that causes arrhythmias and autism in humans with Timothy syndrome (Cav1.2-TS) increased Ca2+ currents, diastolic and systolic Ca2+ levels, contractility and the frequency of arrhythmogenic Ca2+ fluctuations in ventricular myocytes. Our data indicate that these changes in Ca2+ signaling resulted from Cav1.2-TS increasing the activity of adjoining WT Cav1.2 channels. Collectively, these data support the concept that oligomerization of Cav1.2 channels via their C termini can result in the amplification of Ca2+ influx into excitable cells.Keywords
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