title: N-Myristoylation is essential for protein phosphatases PPM1A and PPM1B to dephosphorylate their physiological substrates in cells.
abstract: PPM [metal-dependent protein phosphatase, formerly called PP2C (protein phosphatase 2C)] family members play essential roles in regulating a variety of signalling pathways. While searching for protein phosphatase(s) that act on AMPK (AMP-activated protein kinase), we found that PPM1A and PPM1B are N-myristoylated and that this modification is essential for their ability to dephosphorylate the α subunit of AMPK (AMPKα) in cells. N-Myristoylation was also required for two other functions of PPM1A and PPM1B in cells. Although a non-myristoylated mutation (G2A) of PPM1A and PPM1B prevented membrane association, this relocalization did not likely cause the decreased activity towards AMPKα. In in vitro experiments, the G2A mutants exhibited reduced activities towards AMPKα, but much higher specific activity against an artificial substrate, PNPP (p-nitrophenyl phosphate), compared with the wild-type counterparts. Taken together, the results of the present study suggest that N-myristoylation of PPM1A and PPM1B plays a key role in recognition of their physiological substrates in cells.
authors.affiliation: Department of Biochemistry, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
authors.forename: Toko
authors.initials: T
authors.lastname: Chida
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Ando
authors.forename: Tasuku
authors.initials: T
authors.lastname: Matsuki
authors.forename: Yutaro
authors.initials: Y
authors.lastname: Masu
authors.forename: Yuko
authors.initials: Y
authors.lastname: Nagaura
authors.forename: Teruko
authors.initials: T
authors.lastname: Takano-Yamamoto
authors.forename: Shinri
authors.initials: S
authors.lastname: Tamura
authors.forename: Takayasu
authors.initials: T
authors.lastname: Kobayashi
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001483:Base Sequence; D020134:Catalytic Domain / Q000235:genetics; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D019814:Myristic Acid / Q000378:metabolism; D009596:Nitrophenols / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D000071636:Protein Phosphatase 2C; D011499:Protein Processing, Post-Translational; D034741:RNA, Small Interfering / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D009596:Nitrophenols; D009943:Organophosphorus Compounds; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D019814:Myristic Acid; C008644:nitrophenylphosphate; D055372:AMP-Activated Protein Kinases; C000607456:PPM1A protein, human; C000607457:PPM1B protein, human; C000607460:PPM1G protein, human; D010749:Phosphoprotein Phosphatases; C000607466:Ppm1a protein, mouse; C000607467:Ppm1b protein, mouse; D000071636:Protein Phosphatase 2C