Identification of protein phosphatases dephosphorylating mRNP proteins from cryptobiotic gastrulae of the brine shrimp A. salina

Chris Thoen, Lauris Van Hove, Philip Cohen, Herman Slegers

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    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.

    Original languageEnglish
    Pages (from-to)84-90
    Number of pages7
    JournalBiochemical and Biophysical Research Communications
    Issue number1
    Publication statusPublished - 30 Aug 1985


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