Regulation of the meiosis-inhibited protein kinase, a p38(MAPK) isoform, during meiosis and following fertilization of seastar oocytes.
J Biol Chem
; 275(44): 34236-44, 2000 Nov 03.
Article
em En
| MEDLINE
| ID: mdl-10906138
ABSTRACT
A p38(MAPK) homolog Mipk (meiosis-inhibited protein kinase) was cloned from seastar oocytes. This 40-kDa protein shares approximately 65% amino acid identity with mammalian p38-alpha isoforms. Mipk was one of the major tyrosine-phosphorylated proteins in immature oocytes arrested at the G(2)/M transition of meiosis I. The tyrosine phosphorylation of Mipk was increased in response to anisomycin, heat, and osmotic shock of oocytes. During 1-methyladenine-induced oocyte maturation, Mipk underwent tyrosine dephosphorylation and remained dephosphorylated in mature oocytes and during the early mitotic cell divisions until approximately 12 h after fertilization. At the time of differentiation and acquisition of G phases in the developing embryos, Mipk was rephosphorylated on tyrosine. In oocytes that were microinjected with Mipk antisense oligonucleotides and subsequently were allowed to mature and become fertilized, differentiation was blocked. Because MipK antisense oligonucleotides and a dominant-negative (K62R)Mipk when microinjected into immature oocytes failed to induce germinal vesicle breakdown, inhibition of Mipk function was not sufficient by itself to cause oocyte maturation. These findings point to a putative role for Mipk in cell cycle control as a G-phase-promoting factor.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Oócitos
/
Estrelas-do-Mar
/
Proteínas Quinases Ativadas por Mitógeno
/
Fertilização
/
Isoenzimas
/
Meiose
Limite:
Animals
/
Humans
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2000
Tipo de documento:
Article
País de afiliação:
Canadá