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Direct activation of cdc2 with phosphatase: identification of p13 sucl ‐sensitive and insensitive steps
Author(s) -
Jessus Catherine,
Ducommun Bernard,
Beach David
Publication year - 1990
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(90)90002-c
Subject(s) - xenopus , dephosphorylation , maturation promoting factor , phosphatase , metaphase , prophase , microbiology and biotechnology , biology , biochemistry , protein kinase a , phosphorylation , cyclin dependent kinase 1 , chemistry , cell , cell cycle , meiosis , gene , chromosome
In Xenopus oocytes, activation of MPF during prophase-metaphase transition is associated with the tyrosine dephosphorylation of the cdc2 protein. In vivo and in cell-free extracts kinase activation can be inhibited by excess p13suc1, a subunit of the protein kinase. Here we have demonstrated that affinity-purified cdc2 from Xenopus prophase oocytes may be activated in vitro by exposure to potato acid phosphatase. In vitro, excess p13 does not inhibit tyrosine dephosphorylation of prophase cdc2, but nonetheless binds and prevents the activation of the enzyme. By contrast, fully activated enzyme from metaphase Xenopus eggs is insensitive to excess p13. These observations define a p13-sensitive state in the activation of fully active cdc2 that follows tyrosine dephosphorylation.