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Regulatory subunit of type II cAMP‐dependent protein kinase as substrate and inhibitor of protein phosphatase‐1 and ‐2A
Author(s) -
Vereb György,
Erd″odi Ferenc,
Tóth Béla,
Bot György
Publication year - 1986
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(86)80314-3
Subject(s) - protein subunit , phosphatase , protein kinase a , protein phosphatase 2 , chemistry , protein phosphatase 1 , substrate (aquarium) , kinase , biochemistry , microbiology and biotechnology , phosphorylation , biology , gene , ecology
The dissociated regulatory subunit (R II ) of autophosphorylated cAMP‐dependent protein kinase II was dephosphorylated by the catalytic subunits of protein phosphatase‐1 and ‐2A (phosphatase‐1 c and ‐2A c ) and by a high‐ M r , polycation‐dependent form of phosphatase‐2A (2A 0 ) with K m values of 5,0.3 and 1 μ M , respectively. Dissociation of protein kinase by cAMP preferentially increased the dephosphorylation of R II by phosphatase‐1 c , whereas polycations (histone H1 or polybrene) markedly stimulated phosphatase‐2A c and ‐2A o even in the absence of cAMP. Thiophosphorylated R II inhibited the dephosphorylation of phosphorylase a by these phosphatases with half‐maximum inhibitory concentrations of 0.1–0.36 μM.