Proteolysis activated protein kinase in Dictyostelium discoideum.
In the search for MBP phosphorylating activities in Dictyostelium discoideum, we have found a proteolysis-activated protein kinase. This activity which is distributed between the soluble and the particulate fractions of the cell, uses MBP and histone as substrate and has a molecular mass of 140 kDa as detected in an 'in situ' assay. This protein kinase has several features shared by the protein kinase C family, such as substrate specificity and sensitivity to proteolysis, but its molecular mass is much larger than that described for the known protein kinase C isoforms. To better characterize this activity we have studied its sensitivity to several protein kinase C inhibitors and activators. This protein kinase is activated neither by phorbol ester nor by phosphatidylserine or Ca2+. The activity is inhibited by staurosporine and PKC zeta pseudosubstrate, but is not affected by the specific protein kinase C inhibitor bisindolylmaleimide. These data lead us to propose that proteolytically activated Dictyostelium protein kinase belongs to the recently described protein kinase C-related family.
Nuñez
A
A
Departamento de Bioquímica Universidad Autónoma de Madrid, España.
Fernández-Renart
M
M
D000818:Animals; D002478:Cells, Cultured; D002853:Chromatography, Liquid; D004023:Dictyostelium / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006657:Histones / Q000378:metabolism; D004676:Myelin Basic Protein / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism*; D019606:Phosphoamino Acids / Q000378:metabolism; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000302:isolation & purification / Q000378:metabolism*; D019311:Staurosporine / Q000494:pharmacology; D013379:Substrate Specificity
D004791:Enzyme Inhibitors; D006657:Histones; D004676:Myelin Basic Protein; D019606:Phosphoamino Acids; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases; D010447:Peptide Hydrolases; D019311:Staurosporine