title: Studies on the phosphorylation of protein kinase C-alpha.
abstract: A kinase-defective protein kinase C-alpha mutant is shown to be a phosphoprotein when expressed in COS-1 cells, indicating that intramolecular phosphorylation does not fully account for the phosphate content of protein kinase C-alpha. Furthermore, evidence is presented that the intermolecular phosphorylation of protein kinase C-alpha is due to an activity other than protein kinase C-alpha itself, and this phosphorylation appears to be necessary for protein kinase C-alpha activity. By contrast, the characteristic shift in apparent molecular mass consequent on phosphorylation in vivo can be accounted for by autophosphorylation, as demonstrated in vitro. The relationship between these phosphorylated protein kinase C-alpha species is discussed.
authors.affiliation: Protein Phosphorylation Laboratory, Imperial Cancer Research Fund, London, U.K.
authors.forename: C
authors.initials: C
authors.lastname: Pears
authors.forename: S
authors.initials: S
authors.lastname: Stabel
authors.forename: S
authors.initials: S
authors.lastname: Cazaubon
authors.forename: P J
authors.initials: PJ
authors.lastname: Parker
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D004591:Electrophoresis, Polyacrylamide Gel; D005910:Glioma; D008970:Molecular Weight; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014162:Transfection
chemical_list: D010750:Phosphoproteins; D011493:Protein Kinase C; D000135:Acid Phosphatase