Dephosphorylation of autophosphorylated Ca2+/calmodulin-dependent protein kinase II by protein phosphatase 2C.
It has been demonstrated that okadaic acid-insensitive protein phosphatases are involved in dephosphorylation of autophosphorylated Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) in rat cerebellar granule cells (Fukunaga, K., Rich, D. P., and Soderling, T. R. (1989) J. Biol. Chem. 264, 21830-21836). In the present study, recombinant rat protein phosphatase 2C (PrP-2C) expressed in Escherichia coli could dephosphorylate both Thr286/287 and Thr305/306 phosphorylation sites of CaM kinase II, which are responsible for the generation of Ca(2+)-independent activity and the inhibition of the total activity, respectively. The dephosphorylation of Thr286/287 and Thr305/306 was accomplished within 15 min at 0 degrees C and totally dependent on Mg2+. Phosphopeptide mapping of the CNBr-cleaved 32P-labeled CaM kinase II revealed that PrP-2C was relatively specific for dephosphorylation of Thr286/287 and Thr305/306 in the autophosphorylated CaM kinase II. These results suggest that PrP-2C has a role in the regulation of the Ca(2+)-independent activity of CaM kinase II in the neural cells.
Fukunaga
K
K
Department of Pharmacology, Kumamoto University School of Medicine, Japan.
Kobayashi
T
T
Tamura
S
S
Miyamoto
E
E
D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D046911:Macromolecular Substances; D008970:Molecular Weight; D010446:Peptide Fragments / Q000302:isolation & purification; D010449:Peptide Mapping; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism
D046911:Macromolecular Substances; D010446:Peptide Fragments; D011994:Recombinant Proteins; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D010749:Phosphoprotein Phosphatases