Phosphorylation of histone H2A by protein kinase C and identification of the phosphorylation site.
In regenerating rat liver, nuclear protein histone H2A was shown to be phosphorylated on its amino-terminal serine residue [Sung et al. (1971) J. Biol. Chem. 246, 1358-1364], but the protein kinase which phosphorylates this residue has not been identified. To evaluate the possibility that protein kinase C can phosphorylate this residue, calf thymus histone H2A was 32P-labeled by incubation with [gamma-32P]ATP and highly purified protein kinase C from rat brain in the presence of calcium and phospholipid. About 1 mol of 32P was incorporated per mol of histone H2A and the Km and apparent Vmax of the reaction were calculated to be 2.1 microM and 0.35 mumol/min/mg, respectively. So histone H2A seemed to be a good substrate for protein kinase C. Further, the proteolytic phosphopeptides of 32P-labeled histone H2A were isolated by means of a series of column chromatographies and analyzed for their amino acid compositions. Comparison of the data with the known primary structure of histone H2A revealed their amino acid sequence as 1Ser-Gly-Arg. These data suggest that protein kinase C may be a candidate for the protein kinase which phosphorylates the amino-terminal serine residue of histone H2A during the regeneration of rat liver.
Takeuchi
F
F
Department of Biochemistry, Fukui Medical School.
Hashimoto
E
E
Yamamura
H
H
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000201:enzymology; D002417:Cattle; D006657:Histones / Q000737:chemistry / Q000378:metabolism*; D066298:In Vitro Techniques; D007700:Kinetics; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D006657:Histones; D011493:Protein Kinase C