Phosphorylation and activation of Ca2+/calmodulin-dependent protein kinase phosphatase by Ca2+/calmodulin-dependent protein kinase II.
Ca2+/calmodulin-dependent protein kinase phosphatase (CaMKPase) is a protein phosphatase which dephosphorylates autophosphorylated Ca2+/calmodulin-dependent protein kinase II (CaMKII) and deactivates the enzyme (Ishida, A., Kameshita, I. and Fujisawa, H. (1998) J. Biol. Chem. 273, 1904-1910). In this study, a phosphorylation-dephosphorylation relationship between CaMKII and CaMKPase was examined. CaMKPase was not significantly phosphorylated by CaMKII under the standard phosphorylation conditions but was phosphorylated in the presence of poly-L-lysine, which is a potent activator of CaMKPase. The maximal extent of the phosphorylation was about 1 mol of phosphate per mol of the enzyme and the phosphorylation resulted in an about 2-fold increase in the enzyme activity. Thus, the activity of CaMKPase appears to be regulated through phosphorylation by its target enzyme, CaMKII.
Kameshita
I
I
Department of Biochemistry, Asahikawa Medical College, Japan.
Ishida
A
A
Fujisawa
H
H
D000818:Animals; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D020134:Catalytic Domain; D004789:Enzyme Activation / Q000187:drug effects; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D010766:Phosphorylation; D011107:Polylysine / Q000494:pharmacology; D051381:Rats
D011107:Polylysine; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C110531:calmodulin dependent protein kinase II phosphatase; D010749:Phosphoprotein Phosphatases