title: Regulation of Ca(2+)/calmodulin-dependent protein kinase phosphatase (CaMKP) by oxidation/reduction at Cys-359.
abstract: Ca(2+)/calmodulin-dependent protein kinase phosphatase (CaMKP/PPM1F) is a Ser/Thr protein phosphatase that dephosphorylates and regulates multifunctional Ca(2+)/calmodulin-dependent protein kinases. Although CaMKP is known to be activated by phosphorylation with CaMKII and stimulated by the addition of polycations such as poly-l-lysine, detailed mechanisms of regulation of CaMKP in vivo still remain unclear. In the present study, we found that CaMKP is regulated by oxidation/reduction at Cys residue(s). When CaMKP was incubated with H(2)O(2), time- and dose-dependent inactivation of the enzyme was observed. This inactivation was restored when the inactivated CaMKP was treated with a reducing agent such as 2-mercaptoethanol. Since there are three Cys residues (Cys-259, Cys-315, and Cys-359) in human CaMKP (hCaMKP), we produced three point mutants of hCaMKP, CaMKP(C259S), CaMKP(C315S), and CaMKP(C359S), of which the Cys residues were replaced by Ser residues. Among these Cys-substituted mutants, only CaMKP(C359S) exhibited significant tolerance against oxidation by H(2)O(2). Incubation of CaMKP with H(2)O(2) led to formation of disulfide bond between Cys-359 and Cys-259/Cys-315, resulting in the inactivation of the enzyme. These results suggest that hCaMKP activity is reversibly regulated by oxidation/reduction at Cys-359.
authors: Department of Life Sciences, Kagawa University, Kagawa, Japan.
authors: Hiromi
authors: H
authors: Baba
authors: Noriyuki
authors: N
authors: Sueyoshi
authors: Yasushi
authors: Y
authors: Shigeri
authors: Atsuhiko
authors: A
authors: Ishida
authors: Isamu
authors: I
authors: Kameshita
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects; D003545:Cysteine / Q000378:metabolism*; D004220:Disulfides / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D057809:HEK293 Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007460:Iodoacetamide / Q000494:pharmacology; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects; D010749:Phosphoprotein Phosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017354:Point Mutation; D017434:Protein Structure, Tertiary; D051381:Rats; D013997:Time Factors
chemical_list: D004220:Disulfides; D006861:Hydrogen Peroxide; C459194:PPM1F protein, human; D010749:Phosphoprotein Phosphatases; D003545:Cysteine; D007460:Iodoacetamide