Phosphorylation of the calcium antagonist receptor of the voltage-sensitive calcium channel by cAMP-dependent protein kinase.
Physiological studies indicate that voltage-sensitive calcium channels are regulated by cAMP and protein phosphorylation. The calcium antagonist receptor of the voltage-sensitive calcium channel from transverse-tubule membranes consists of three subunits, designated alpha, beta, and gamma. The catalytic subunit of cAMP-dependent protein kinase phosphorylates both the alpha and beta subunits of the purified receptor at a rate and extent that suggests they are potential physiological substrates of this enzyme. The phosphorylation of the alpha and beta subunits in transverse-tubule membranes was analyzed by two-dimensional gel electrophoresis. In intact transverse-tubule membranes, the alpha subunit is not significantly phosphorylated. However, the beta subunit, identified by its Mr, pI, and binding to wheat germ agglutinin-Sepharose, was one of the substrates selectively phosphorylated by cAMP-dependent protein kinase in transverse-tubule membranes. These results suggest that cAMP-dependent phosphorylation of the beta subunit of the calcium antagonist receptor may be an important regulatory mechanism for calcium channel function.
Curtis
B M
BM
Catterall
W A
WA
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels; D004563:Electrochemistry; D066298:In Vitro Techniques; D007473:Ion Channels / Q000378:metabolism*; D007700:Kinetics; D008970:Molecular Weight; D009132:Muscles / Q000378:metabolism; D010766:Phosphorylation; D011487:Protein Conformation; D011494:Protein Kinases / Q000378:metabolism*; D011817:Rabbits; D011978:Receptors, Nicotinic / Q000302:isolation & purification / Q000378:metabolism*
D015220:Calcium Channels; D007473:Ion Channels; D011978:Receptors, Nicotinic; D011494:Protein Kinases; D002118:Calcium