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Inhibition of protein tyrosine phosphatases blocks calcium‐induced activation of metaphase II‐arrested oocytes of Xenopus laevis
Author(s) -
Bodart Jean-François,
Béchard David,
Bertout Marc,
Rousseau Arlette,
Gan Julian,
Vilain Jean-Pierre,
Flament Stéphane
Publication year - 1999
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/s0014-5793(99)00986-2
Subject(s) - xenopus , chemistry , metaphase , phosphatase , protein tyrosine phosphatase , calcium , microbiology and biotechnology , tyrosine , phosphorylation , biochemistry , biology , gene , chromosome , organic chemistry
We have studied the effect of a protein tyrosine phosphatases (PTP) inhibitor on calcium‐induced activation of Xenopus laevis oocytes arrested at metaphase II. Ammonium molybdate microinjection blocked pronucleus formation following A23187 treatment while cortical granules still underwent exocytosis. Pronuclei still occurred in ammonium molybdate‐injected oocytes following 6‐DMAP addition. Changes that usually occurred following A23187 exposure were inhibited in the presence of ammonium molybdate in the oocyte: MAPK dephosphorylation, p34 cdc2 rephosphorylation and cyclin B2 and p39 mos proteolysis. These results suggest that a PTP is involved in the activation of the ubiquitin‐dependent degradation machinery.