title: Identification of protein phosphatases dephosphorylating mRNP proteins from cryptobiotic gastrulae of the brine shrimp A. salina.
abstract: In the cytosol of A. salina cryptobiotic gastrulae at least five protein phosphatases active on phosphorylase a have been detected by ion exchange chromatography on DEAE-cellulose. Only two of these enzymes (PP-X and PP-Y) are active in mRNP dephosphorylation. Both enzymes are insensitive to inhibitor-1 and -2 and stimulation of enzymatic activity (2.5-fold with PP-X and 6.5-fold with PP-Y) can be accomplished by ethanol treatment of the native enzymes, or freeze-thawing in the presence of 1.7% (v/v) 2-mercaptoethanol. These properties allow PP-X and PP-Y to be classified as type-2A enzymes according to the nomenclature of Cohen. This paper is the first report of protein phosphatases capable of dephosphorylating mRNP proteins.
mesh_terms: D000818:Animals; D001156:Artemia / Q000196:embryology / Q000201:enzymology*; D002848:Chromatography, DEAE-Cellulose; D003600:Cytosol / Q000201:enzymology; D000431:Ethanol / Q000494:pharmacology; D005615:Freezing; D005775:Gastrula / Q000201:enzymology; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D010762:Phosphorylase a / Q000378:metabolism; D010766:Phosphorylation; D012261:Ribonucleoproteins / Q000378:metabolism*; D012969:Sodium Fluoride / Q000494:pharmacology
chemical_list: D012261:Ribonucleoproteins; C026452:messenger ribonucleoprotein; D000431:Ethanol; D012969:Sodium Fluoride; D010762:Phosphorylase a; D010749:Phosphoprotein Phosphatases