Control of voltage-dependent Ca2+ channels by G protein-coupled receptors

Item Type:	Review
Title:	Control of voltage-dependent Ca2+ channels by G protein-coupled receptors
Creators Name:	Rosenthal, W. and Hescheler, J. and Trautwein, W. and Schultz, G.
Abstract:	G proteins act as transducers between membrane receptors activated by extracellular signals and enzymatic effectors controlling the concentration of cytosolic signal molecules such as cAMP, cGMP, inositol phosphates and Ca2+. In some instances, the receptor/G protein-induced changes in the concentration of cytosolic signal molecules correlate with activity changes of voltage-dependent Ca2+ channels. Ca2+ channel modulation, in these cases, requires the participation of protein kinases whose activity is stimulated by cytosolic signal molecules. The respective protein kinases phosphorylate Ca2+ channel-forming proteins or unknown regulatory components. More recent findings suggest another membrane-confined mechanism that does not involve cytosolic signal molecules but rather a more direct control of voltage-dependent Ca2+ channels by G proteins. Modulation of Ca2+ channel activity that follows this apparently membrane-confined mechanism has been described to occur in neuronal, cardiac, and endocrine cells. The G protein involved in the hormonal stimulation of Ca2+ channels in endocrine cells may belong to the family of Gi-type G proteins, which are functionally uncoupled from activating receptors by pertussis toxin. The G protein Gs, which is activated by cholera toxin, may stimulate cardiac Ca2+ channels without the involvement of a cAMP-dependent intermediate step. Hormonal inhibition of Ca2+ channels in neuronal and endocrine cells is mediated by a pertussis toxin-sensitive G protein, possibly Go. Whether G proteins act by binding directly to Ca2+ channels or through interaction with as yet undetermined regulatory components of the plasma membrane remains to be clarified.
Keywords:	Transmembranous Signaling, Receptors, Guanine Nucleotide-Binding Proteins (G proteins), Ca2+ Channels, Animals
Source:	FASEB Journal
ISSN:	0892-6638
Publisher:	Federation of American Societies for Experimental Biology
Volume:	2
Number:	12
Page Range:	2784-2790
Date:	September 1988
Official Publication:	http://www.fasebj.org/cgi/content/abstract/2/12/2784
PubMed:	View item in PubMed

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