Identification and characterization of CaMKP-N, nuclear calmodulin-dependent protein kinase phosphatase. |
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| Authors: | M Takeuchi A Ishida I Kameshita T Kitani S Okuno H Fujisawa |
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| Affiliation: | Department of Biochemistry, Asahikawa Medical College, Asahikawa, Hokkaido 078-8510, Japan. |
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| Abstract: | Calmodulin-dependent protein kinase phosphatase (CaMKP) dephosphorylates and concomitantly deactivates multifunctional Ca(2+)/calmodulin-dependent protein kinases (CaMKs), such as CaMKI, CaMKII, and CaMKIV. In the present study, a nuclear CaMKP-related protein, CaMKP-N, was identified. This protein consisted of 757 amino acid residues with a calculated molecular weight of 84,176. Recombinant CaMKP-N dephosphorylated CaMKIV. The activity of CaMKP-N requires Mn(2+) ions and is stimulated by polycations. Transiently expressed CaMKP-N in COS-7 cells was localized in the nucleus. This finding together with previous reports regarding localization of CaMKs indicates that CaMKP-N dephosphorylates CaMKIV and nuclear CaMKII, whereas CaMKP dephosphorylates CaMKI and cytosolic CaMKII. |
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