Isoform-specific phosphorylation of fission yeast type 2C protein phosphatase.
Protein phosphatase 2C (PP2C) is one of the four major protein serine/threonine phosphatases of eukaryotes and is implicated in the regulation of various cellular functions. With the goal of elucidating the mechanism responsible for regulating PP2C functions, we investigated the significance of phosphorylation of fission yeast Ptc1, Ptc2, and Ptc3, the yeast orthologs of mammalian PP2C. Both Ptc2 and Ptc3 but not Ptc1 were phosphorylated stoichiometrically by casein kinase II on serine residues at their carboxy-terminal regions. Mutational analysis of Ptc2 and Ptc3 revealed that serine residues of the conserved sequence (Ser-X-Ser-X-X-Glu/Asp) of these proteins were the phosphorylation sites. Interestingly, the activities of Ptc2 and Ptc3 were decreased 25 +/- 7.5% and increased 55 +/- 3.7%, respectively, by phosphorylation. In addition, the same site(s) of Ptc2 was phosphorylated when the protein was expressed in fission yeast cells. These results suggest that phosphorylation of PP2C plays important physiological roles in fission yeast cells.
Kobayashi
T
T
Institute of Development, Aging and Cancer, Tohoku University, Sendai, 980-8575, Japan.
Sadaie
M
M
Ohnishi
M
M
Wang
H
H
Ikeda
S
S
Hanada
M
M
Yanagawa
Y
Y
Nakajima
T
T
Tamura
S
S
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D017124:Conserved Sequence; D005656:Fungal Proteins / Q000378:metabolism; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D010766:Phosphorylation; D054648:Protein Phosphatase 2; D000071636:Protein Phosphatase 2C; D011994:Recombinant Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000201:enzymology / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D005656:Fungal Proteins; D007527:Isoenzymes; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; C000607456:PPM1A protein, human; C000607457:PPM1B protein, human; C000607460:PPM1G protein, human; C087358:PTC1 protein, S cerevisiae; C000607464:PTC3 protein, S cerevisiae; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2; D000071636:Protein Phosphatase 2C