Activation of Ca2+‐activated Cl channel ANO1 by localized Ca2+ signals

X Jin, S Shah, X Du, H Zhang… - The Journal of …, 2016 - Wiley Online Library
X Jin, S Shah, X Du, H Zhang, N Gamper
The Journal of physiology, 2016Wiley Online Library
Abstract Ca2+‐activated chloride channels (CaCCs) regulate numerous physiological
processes including epithelial transport, smooth muscle contraction and sensory processing.
Anoctamin‐1 (ANO1, TMEM16A) is a principal CaCC subunit in many cell types, yet our
understanding of the mechanisms of ANO1 activation and regulation are only beginning to
emerge. Ca2+ sensitivity of ANO1 is rather low and at negative membrane potentials the
channel requires several micromoles of intracellular Ca2+ for activation. However, global …
Abstract
Ca2+‐activated chloride channels (CaCCs) regulate numerous physiological processes including epithelial transport, smooth muscle contraction and sensory processing. Anoctamin‐1 (ANO1, TMEM16A) is a principal CaCC subunit in many cell types, yet our understanding of the mechanisms of ANO1 activation and regulation are only beginning to emerge. Ca2+ sensitivity of ANO1 is rather low and at negative membrane potentials the channel requires several micromoles of intracellular Ca2+ for activation. However, global Ca2+ levels in cells rarely reach such levels and, therefore, there must be mechanisms that focus intracellular Ca2+ transients towards the ANO1 channels. Recent findings indeed indicate that ANO1 channels often co‐localize with sources of intracellular Ca2+ signals. Interestingly, it appears that in many cell types ANO1 is particularly tightly coupled to the Ca2+ release sites of the intracellular Ca2+ stores. Such preferential coupling may represent a general mechanism of ANO1 activation in native tissues.
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