The beta 1-subunit is essential for modulation by protein kinase C of an human and a non-human L-type Ca2+ channel.
We have investigated in Xenopus oocytes the effects of phorbol ester-induced protein kinase C (PKC) stimulation on dihydropyridine (DHP)-insensitive and -sensitive Ca2+ channels. DHP-insensitive Ba2+ currents (IBa) were recorded from endogenous channels in non-injected oocytes and in oocytes injected with cRNAs encoding the auxiliary rabbit alpha 2/delta and beta 1 Ca2+ channel subunits. A human alpha 1C cRNA, injected alone or in combination with cRNAs of the auxiliary subunits, was used for studying DHP-sensitive IBa. We found that DHP-insensitive IBa was increased by 4 beta-phorbol 12-myristate 13-acetate (PMA), while DHP-sensitive IBa was decreased. In both cases, the effects depended only on the co-expression of the beta 1 subunit.
Department of Pharmacology, University of Bern, Switzerland.
A
A
Bouron
N M
NM
Soldatov
H
H
Reuter
D000818:Animals; D001464:Barium / Q000378:metabolism; D001483:Base Sequence; D015220:Calcium Channels / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004095:Dihydropyridines / Q000494:pharmacology; D004553:Electric Conductivity; D006801:Humans; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D009865:Oocytes; D011493:Protein Kinase C / Q000378:metabolism*; D011817:Rabbits; D013329:Structure-Activity Relationship; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014981:Xenopus
D015220:Calcium Channels; D004095:Dihydropyridines; D009838:Oligodeoxyribonucleotides; D001464:Barium; C038806:1,4-dihydropyridine; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate