Calmodulin and CaMKII as Ca2+
Switches for Cardiac Ion Channels
Changes in intracellular Ca2+ are among the most diverse and important means of cell signaling. In the heart, signaling pathways from excitation-contraction coupling to humoral activation of hypertrophic responses all rely on changes in the concentration of intracellular Ca2+. Ion channels belong to a class of signaling proteins that is particularly sensitive to a change in intracellular Ca2+, which is the final signal of all coordinated ion channel activity. Thus, regulation of ion channel function by Ca2+ provides an essential feedback mechanism for cellular electrical activity. Two intracellular proteins activated by Ca2+, the ubiquitous Ca2+ binding protein calmodulin (CaM), and the Ca2+/CaM-dependent protein kinase CaMKII, dictate most of the actions of intracellular Ca2+ on cardiac ion channels. In this chapter, we highlight key roles for CaM and CaMKII in cardiac myocytes as downstream integrators of Ca2+ signals in the regulation of cardiac ion channels and consequent actions on myocyte excitability. © 2014 Elsevier Inc. All rights reserved.
- Cardiac Electrophysiology: From Cell to Bedside: Sixth Edition
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International Standard Book Number 13 (ISBN-13)
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