Broad specificity in binding of NIPP-1, nuclear inhibitor of protein phosphatase-1, to PP1 isoforms in vivo.
Protein phosphatase type-1 (PP1), one of the most abundant Ser/Thr protein phosphatases, plays a central role in the regulation of various cell functions. Almost all the PP1 molecules exist as holoenzymes in vivo consisting of a catalytic subunit (PP1C) and a variable regulatory subunit that regulates substrate specificity and/or subcellular localization. In order to clarify fine regulation of PP1, we overexpressed a nuclear inhibitor of PP1 (NIPP-1) in a Flag-tagged form in mammalian cells. The Flag-tagged NIPP-1 was found to be immunoprecipitated with three isoforms of PP1C, namely, PP1alpha, PP1gamma1, and PP1delta with a similar efficiency, suggesting that NIPP-1 makes a complex with the PP1C through the region conserved among the three isoforms. These results suggested that NIPP-1 can be involved in the regulation of various PP1 holoenzymes in vivo.
Kim
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Division of Biochemical Oncology and Immunology, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan.
Shima
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Nakamura
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Kikuchi
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K
D000818:Animals; D019556:COS Cells; D002352:Carrier Proteins; D002460:Cell Line; D004722:Endoribonucleases; D004791:Enzyme Inhibitors / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D054645:Protein Phosphatase 1; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D007527:Isoenzymes; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; C021042:protein phosphatase inhibitor-1; D004722:Endoribonucleases; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; C097081:PPP1R8 protein, human