Phosphorylation and activation of nuclear Ca(2+)/calmodulin-dependent protein kinase phosphatase (CaMKP-N/PPM1E) by Ca(2+)/calmodulin-dependent protein kinase I (CaMKI)
- Authors
- Onouchi, T., Sueyoshi, N., Ishida, A., and Kameshita, I.
- ID
- ZDB-PUB-120529-42
- Date
- 2012
- Source
- Biochemical and Biophysical Research Communications 422(4): 703-709 (Journal)
- Registered Authors
- Keywords
- CaM kinase, CaMKP-N/PPM1E, CaMKP/PPM1F, protein phosphorylation, proteolytic processing, translocation
- MeSH Terms
-
- Alanine/genetics
- Alanine/metabolism
- Amino Acid Sequence
- Amino Acid Substitution
- Animals
- Calcium-Calmodulin-Dependent Protein Kinase Type 1/metabolism*
- Cell Line, Tumor
- Enzyme Activation
- Mice
- Molecular Sequence Data
- Mutation
- Phosphoprotein Phosphatases/genetics
- Phosphoprotein Phosphatases/metabolism*
- Phosphorylation
- Rats
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Serine/genetics
- Serine/metabolism
- PubMed
- 22627141 Full text @ Biochem. Biophys. Res. Commun.
Nuclear Ca2+/calmodulin-dependent protein kinase phosphatase (CaMKP-N/PPM1E) is an enzyme that dephosphorylates and downregulates multifunctional Ca2+/calmodulin-dependent protein kinases (CaMKs) as well as AMP-dependent protein kinase. In our previous study, we found that zebrafish CaMKP-N (zCaMKP-N) underwent proteolytic processing and translocated to cytosol in a proteasome inhibitor-sensitive manner. In the present study, we found that zCaMKP-N is regulated by phosphorylation at Ser-480. When zCaMKP-N was incubated with the activated CaMKI, time-dependent phosphorylation of the enzyme was observed. This phosphorylation was significantly reduced when Ser-480 was replaced by Ala, suggesting that CaMKI phosphorylates Ser-480 of zCaMKP-N. Phosphorylation-mimic mutants, S480D and S480E, showed higher phosphatase activities than those of wild type and S480A mutant in solution-based phosphatase assay using various substrates. Furthermore, autophosphorylation of CaMKII after ionomycin treatment was more severely attenuated in Neuro2a cells when CaMKII was cotransfected with the phosphorylation-mimic mutant of zCaMKP-N than with the wild-type or non-phosphorylatable zCaMKP-N. These results strongly suggest that phosphorylation of zCaMKP-N at Ser-480 by CaMKI activates CaMKP-N catalytic activity and thereby downregulates multifunctional CaMKs in the cytosol.