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Phosphorylation of the L-type calcium channel beta subunit is involved in beta-adrenergic signal transduction in canine myocardium

Item Type:Article
Title:Phosphorylation of the L-type calcium channel beta subunit is involved in beta-adrenergic signal transduction in canine myocardium
Creators Name:Haase, H. and Karczewski, P. and Beckert, R. and Krause, E.G.
Abstract:Cyclic AMP-mediated phosphorylation of calcium channel subunits was studied in vitro and in vivo in preparations from dog heart. Calcium channels in native cardiac membranes were phosphorylated by cAMP-dependent protein kinase (PKA) solubilized with digitonin and subsequently immunoprecipitated using a polyclonal antibody generated against the deduced carboxy-terminal sequence of the cardiac beta subunit. A 62 kDa protein was identified as the major PKA-substrate in the immunoprecipitates. In the intact myocardium, this putative beta subunit was found to be phosphorylated in response to cAMP elevating agents. In contrast, no phosphorylation of a protein with an electrophoretic mobility similar to the alpha 1 subunit was detected, although 1,4-dihydropyridine receptor sites were recovered in the immunoprecipitates. Thus, we suggest that PKA-mediated phosphorylation of the beta subunit is the major mechanism for beta-adrenergic regulation of cardiac L-type calcium channel activity.
Keywords:Calcium Channel, Canine Heart, Immunoprecipitation, Peptide Antibody, Protein Phosphorylation, Beta Subunit, Animals, Dogs
Source:FEBS Letters
ISSN:0014-5793
Publisher:Elsevier (The Netherlands)
Volume:335
Number:2
Page Range:217-222
Date:6 December 1993
Official Publication:https://doi.org/10.1016/0014-5793(93)80733-B
PubMed:View item in PubMed

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