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Regulation of Cardiac Calcium Channels in the Fight-or-Flight Response

[ Vol. 8 , Issue. 1 ]

Author(s):

William A. Catterall   Pages 12 - 21 ( 10 )

Abstract:


Intracellular calcium transients generated by activation of voltage-gated calcium (CaV) channels generate local signals, which initiate physiological processes such as secretion, synaptic transmission, and excitation-contraction coupling. Regulation of calcium entry through CaV channels is crucial for control of these physiological processes. In this article, I review experimental results that have emerged over several years showing that cardiac CaV1.2 channels form a local signaling complex, in which their proteolytically processed distal C-terminal domain, an A-Kinase Anchoring Protein, and cyclic AMP-dependent protein kinase (PKA) interact directly with the transmembrane core of the ion channel through the proximal C-terminal domain. This signaling complex is the substrate for β-adrenergic up-regulation of the CaV1.2 channel in the heart during the fight-or-flight response. Protein phosphorylation of two sites at the interface between the distal and proximal C-terminal domains contributes importantly to control of basal CaV1.2 channel activity, and phosphorylation of Ser1700 by PKA at that interface up-regulates CaV1.2 activity in response to β-adrenergic signaling. Thus, the intracellular C-terminal domain of CaV1.2 channels serves as a signaling platform, mediating beat-to-beat physiological regulation of channel activity and up-regulation by β-adrenergic signaling in the fight-or-flight response.

Keywords:

A Kinase Anchoring Protein, beta-adrenergic, calcium channel, cAMP-dependent protein kinase, cardiac hypertrophy, Cav1.2, heart failure, L-type calcium current.

Affiliation:

Department of Pharmacology, Box 357280, University of Washington, Seattle, WA 98195-7280.

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