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Cyclic AMP‐dependent phosphorylation and regulation of the cardiac dihydropyridine‐sensitive Ca channel
Author(s) -
Yoshida Akira,
Takahashi Masami,
Nishimura Seiichiro,
Takeshima Hiroshi,
Kokubun Shinichiro
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)80804-p
Subject(s) - protein subunit , phosphorylation , protein kinase a , polyclonal antibodies , forskolin , microbiology and biotechnology , dihydropyridine , complementary dna , microsome , transfection , chemistry , biochemistry , biology , in vitro , antibody , calcium , gene , organic chemistry , immunology
A polyclonal antibody, CR2, prepared using the C‐terminal peptide of the α1 subunit of the rabbit cardiac DHP‐sensitive Ca channel, specifically immunoprecipitated the [ 3 H]PN200‐100‐labeled Ca channel solubilized from cardiac microsomes. The antibody recognized 250 and 200‐kDa cardiac microsomal proteins as determined by immunoblotting, and cAMP‐dependent protein kinase phosphorylated the 250‐kDa, but not the 200‐kDa protein in vitro. CHO cells, transfected with the cardiac subunit cDNA carried by an expression vector, synthesized a 250‐kDa protein which was recognized by CR2. Adding db‐cAMP or forskolin to the transformed CHO cells induced phosphorylation of the 250‐kDa proteina and stimulated the DHP‐sensitive Ba current under patch‐clamp conditions. These results suggested that the cardiac DHP‐sensitive Ca channel was regulated by cAMP‐dependent phosphorylation of the α1 subunit.