Comparison of phosphorylation sites in protamines between protein kinase C and cAMP-dependent protein kinase.
Phosphorylation sites of protamines by protein kinase C and cAMP-dependent protein kinase (protein kinase A) were studied. Using clupeine Y1 as a substrate, protein kinase C phosphorylates both Ser and Thr residues, whereas protein kinase A phosphorylates only Ser residue(s). Protein kinase C phosphorylates all Ser and Thr residues of clupeine Y2 and Z, however protein kinase A phosphorylates mainly Ser9 and slightly Thr5 in clupeine Y2 and Ser6 and Ser10 in clupeine Z. These results suggest that protein kinase C recognizes more sites than those of protein kinase A and may participate in protamine phosphorylation in vivo.
D000595:Amino Acid Sequence; D001665:Binding Sites; D003026:Clupeine / Q000378:metabolism; D008969:Molecular Sequence Data; D010748:Phosphopeptides / Q000032:analysis; D010766:Phosphorylation; D011479:Protamines / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*; D012694:Serine / Q000378:metabolism; D013912:Threonine / Q000378:metabolism
D010748:Phosphopeptides; D011479:Protamines; D013912:Threonine; D012694:Serine; D003026:Clupeine; D011494:Protein Kinases; D011493:Protein Kinase C