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XB-ART-23707
Pflugers Arch 1992 Jun 01;4212-3:247-55.
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Protein kinase C regulation of cardiac calcium channels expressed in Xenopus oocytes.

Bourinet E , Fournier F , Lory P , Charnet P , Nargeot J .


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L-Type cardiac Ca2+ channels expressed in Xenopus oocyte were studied following rat heart ribonucleic acid, messenger (mRNA) injection. We demonstrate that exogenous Ca2+ channels are sensitive to intracellular regulation by protein kinase C (PKC). This was performed by using two types of PKC activators [phorbol esters and a structural analogue of diacyl-glycerol (DAG)] and a specific peptidic inhibitor. Ca2+ channel modulation resulted in an initial increase of the inward current, without any modification of the voltage-dependent properties, and a second delayed phase, specifically observed with phorbol esters, characterized by a progressive decrease in current amplitude. Concomitantly, a reduction of membrane capacitance, reflecting a reduction of the total membrane surface area, was observed. We suggest that this phenomenon underlies the irreversible decrease of the expressed Ba2+ current via sequestration of Ca2+ channels and/or PKC. We also demonstrate that regulation of cardiac mRNA-directed Ca2+ channels by PKC activators was strictly dependent on intracellular Ca2+ concentration, and was partially additive with cyclic-adenosine-monophosphate-(cAMP) dependent regulation.

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Genes referenced: camp

References [+] :
Adachi, Possible involvement of calpain in down-regulation of protein kinase C. 1990, Pubmed