caa a22 4500 397557248 CHVBK 20180308164806.0 cr unu---uuuuu 161202e199607 xx s 000 0 eng 10.1093/oxfordjournals.jbchem.a021380 doi (NATIONALLICENCE)oxford-10.1093/oxfordjournals.jbchem.a021380 Cyclic AMP-Dependent Protein Kinase but Not Protein Kinase C Regulates the Cardiac Ca2+ Channel through Phosphorylation of Its α1 Subunit [Elektronische Daten] [Asako Kameyama, Mark S. Shearman, Kazuo Sekiguchi, Masaki Kameyama] The voltage-dependent L-type Ca2+ channel in the heart is regulated by cAMP-dependent protein kinase (PKA) and possibly by protein kinase C (PKC). We have investigated the channel modulation through phosphorylation by these protein kinases, using liposomes into which Ca2+ channels from bovine heart were reconstituted. Phosphorylation of the proteoliposomes with PKA increased the dihydropyridine-sensltive Ca2+ efflux from them by about 70%. PKA rapidly phosphorylated membrane proteins of 210 and 170 kDa. A dihydropyridine-class Ca2+ channel blocker, [3H]azidopine specifically photo-labeled a protein of 210 kDa, suggesting that the 210-kDa phosphoprotein might be the α1 subunit of the ca2+ channel. In contrast, phosphorylation of the proteoliposomes with PKC failed to modulate the Ca2+ efflux. Although PKC catalyzed the phosphorylation of membrane proteins of 150, 130, 95, 67, and 62 kDa, the 210- and 170-kDa proteins were not phosphorylated by this kinase. These results suggest that phosphorylation of the 210-kDa protein in the cardiac sarcolemma by PKA may be responsible for modulation of the channel function, whereas modulation of the channel by PKC, if it occurs, must be the result of an indirect mechanism, e.g. phosphorylation of a cytoplasmic protein or an associated channel polypeptide, that cannot function in the reconstituted system. © 1996 BY THE JOURNAL OF BIOCHEMISTRY Regular Papers nationallicence Ca2+ channel nationallicence cAMP-dependent protein kinase nationallicence protein kinase C nationallicence protein phosphorylation nationallicence reconstitution nationallicence Kameyama Asako Department of Physiology, Faculty of Medicine, Kagoshima University Kagoshitna 890 aut Shearman Mark S. Biochemistry Department, Merck Sharp & Dohme Research Laboratories Neuroscience Research Centre Essex CM20 2QR UK aut Sekiguchi Kazuo Second Tokushima Institute of New Drug Research, Otsuka Pharmaceutical Co. Tokushima 771-01 aut Kameyama Masaki Department of Physiology, Faculty of Medicine, Kagoshima University Kagoshitna 890 aut The Journal of Biochemistry Oxford University Press 120/1(1996-07), 170-176 0021-924X 120:1<170 1996 120 jbchem https://doi.org/10.1093/oxfordjournals.jbchem.a021380 text/html Onlinezugriff via DOI 1 other jats NATIONALLICENCE 856 40 https://doi.org/10.1093/oxfordjournals.jbchem.a021380 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kameyama Asako Department of Physiology, Faculty of Medicine, Kagoshima University Kagoshitna 890 aut NATIONALLICENCE 700 1- Shearman Mark S. Biochemistry Department, Merck Sharp & Dohme Research Laboratories Neuroscience Research Centre Essex CM20 2QR UK aut NATIONALLICENCE 700 1- Sekiguchi Kazuo Second Tokushima Institute of New Drug Research, Otsuka Pharmaceutical Co. Tokushima 771-01 aut NATIONALLICENCE 700 1- Kameyama Masaki Department of Physiology, Faculty of Medicine, Kagoshima University Kagoshitna 890 aut NATIONALLICENCE 773 0- The Journal of Biochemistry Oxford University Press 120/1(1996-07), 170-176 0021-924X 120:1<170 1996 120 jbchem Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford