Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1993-11-19
pubmed:abstractText
Mitogen-activated protein kinase (MAP kinase) is a serine/threonine kinase whose enzymatic activity is thought to play a crucial role in mitogenic signal transduction and also in the progesterone-induced meiotic maturation of Xenopus oocytes. We have purified MAP kinase from Xenopus oocytes and have shown that the protein is present in metaphase II oocytes under two different forms: an inactive 41-kD protein able to autoactivate and to autophosphorylate in vitro, and an active 42-kD kinase resolved into two tyrosine phosphorylated isoforms on 2D gels. During meiotic maturation, MAP kinase becomes tyrosine phosphorylated and activated following the activation of the M-phase promoting factor (MPF), a complex between the p34cdc2 kinase and cyclin B. In vivo, MAP kinase activity displays a different stability in metaphase I and in metaphase II: protein synthesis is required to maintain MAP kinase activity in metaphase I but not in metaphase II oocytes. Injection of either MPF or cyclin B into prophase oocytes promotes tyrosine phosphorylation of MAP kinase, indicating that its activation is a downstream event of MPF activation. In contrast, injection of okadaic acid, which induces in vivo MPF activation, promotes only a very weak tyrosine phosphorylation of MAP kinase, suggesting that effectors other than MPF are required for the MAP kinase activation. Moreover, in the absence of protein synthesis, cyclin B and MPF are unable to promote in vivo activation of MAP kinase, indicating that this activation requires the synthesis of new protein(s).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1040-452X
pubmed:author
pubmed:issnType
Print
pubmed:volume
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
96-105
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Mitogen-activated protein kinase (MAP kinase) activation in Xenopus oocytes: roles of MPF and protein synthesis.
pubmed:affiliation
INRA/URA CNRS 1449, Université P. et M. Curie, Paris, France.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't