title: Involvement of type 2C phosphatase in the dephosphorylation of 26 kDa phosphoprotein in rat parotid acinar cells.
abstract: Phosphorylation of three particulate proteins with molecular masses of 34, 26, and 22 kDa was stimulated in the presence of cyclic AMP/3-isobutyl-1-methylxanthine in saponin-permeabilized rat parotid acinar cells. When the particulate fraction isolated from the cells labeled with [gamma-32p]ATP was incubated at 30 degrees C, dephosphorylation of the 26 kDa phosphoprotein occurred in the presence of Mg2+ or Mn2+. Okadaic acid had no effect on the Mg(2+)-dependent dephosphorylation of the 26 kDa phosphoprotein. Addition of the recombinant type 2C phosphatase, Mg(2+)-dependent and okadaic acid-insensitive phosphatase, caused a remarkable dephosphorylation of the 26 kDa phosphoprotein. These observations strongly suggest type 2C phosphatase is involved in the dephosphorylation of the 26 kDa phosphoprotein.
authors.affiliation: Department of Physiology, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Yokoyama
authors.forename: M
authors.initials: M
authors.lastname: Hara-Yokoyama
authors.forename: T
authors.initials: T
authors.lastname: Kobayashi
authors.forename: S
authors.initials: S
authors.lastname: Tamura
authors.forename: S
authors.initials: S
authors.lastname: Furuyama
authors.forename: H
authors.initials: H
authors.lastname: Sugiya
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D002463:Cell Membrane Permeability; D000242:Cyclic AMP / Q000378:metabolism / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D004988:Ethers, Cyclic / Q000494:pharmacology; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology; D008970:Molecular Weight; D019319:Okadaic Acid; D010306:Parotid Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010750:Phosphoproteins / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D004988:Ethers, Cyclic; D007527:Isoenzymes; D010750:Phosphoproteins; D011994:Recombinant Proteins; D019319:Okadaic Acid; D004533:Egtazic Acid; D004492:Edetic Acid; D000242:Cyclic AMP; D017027:Protein Tyrosine Phosphatases; D008274:Magnesium; D015056:1-Methyl-3-isobutylxanthine