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.
Author(s):
Thoen, C., Van Hove, L., Cohen, P., Slegers, H.
PubMed:
2994667
Citation:
Thoen, C., Van Hove, L., Cohen, P., Slegers, H.
Thoen, C., Van Hove, L., Cohen, P., Slegers, H.
Biochem Biophys Res Commun
1985
131
84-90
PMID: 2994667