Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
???displayArticle.abstract???
In the Xenopus oocyte system mitogen treatment triggers the G(2)/M transition by transiently inhibiting the cAMP-dependent protein kinase (PKA); subsequently, other signal transduction pathways are activated, including the mitogen-activated protein kinase (MAPK) and polo-like kinase pathways. To study the interactions between these pathways, we have utilized a cell-free oocyte extract that carries out the signaling events of oocyte maturation after addition of the heat-stable inhibitor of PKA, PKI. PKI stimulated the synthesis of Mos and activation of both the MAPK pathway and the Plx1/Cdc25C/cyclin B-Cdc2 pathway. Activation of the MAPK pathway alone by glutathione S-transferase (GST)-Mos did not lead to activation of Plx1 or cyclin B-Cdc2. Inhibition of the MAPK pathway in the extract by the MEK1 inhibitor U0126 delayed, but did not prevent, activation of the Plx1 pathway, and inhibition of Mos synthesis by cycloheximide had a similar effect, suggesting that MAPK activation is the only relevant function of Mos. Immunodepletion of Plx1 completely inhibited activation of Cdc25C and cyclin B-Cdc2 by PKI, indicating that Plx1 is necessary for Cdc25C activation. In extracts containing fully activated Plx1 and Cdc25C, inhibition of cyclin B-Cdc2 by p21(Cip1) had no significant effect on either the phosphorylation of Cdc25C or the activity of Plx1. These results demonstrate that maintenance of Plx1 and Cdc25C activity during mitosis does not require cyclin B-Cdc2 activity.
Dunphy,
The cdc25 protein contains an intrinsic phosphatase activity.
1991, Pubmed
Dunphy,
The cdc25 protein contains an intrinsic phosphatase activity.
1991,
Pubmed Favata,
Identification of a novel inhibitor of mitogen-activated protein kinase kinase.
1998,
Pubmed Fisher,
Dissociation of MAP kinase activation and MPF activation in hormone-stimulated maturation of Xenopus oocytes.
1999,
Pubmed
,
Xenbase Frank-Vaillant,
Two distinct mechanisms control the accumulation of cyclin B1 and Mos in Xenopus oocytes in response to progesterone.
1999,
Pubmed
,
Xenbase Gautier,
cdc25 is a specific tyrosine phosphatase that directly activates p34cdc2.
1991,
Pubmed
,
Xenbase Glover,
Polo-like kinases: a team that plays throughout mitosis.
1998,
Pubmed Gotoh,
Initiation of Xenopus oocyte maturation by activation of the mitogen-activated protein kinase cascade.
1995,
Pubmed
,
Xenbase Gross,
The critical role of the MAP kinase pathway in meiosis II in Xenopus oocytes is mediated by p90(Rsk).
2000,
Pubmed
,
Xenbase Haccard,
Induction of Xenopus oocyte meiotic maturation by MAP kinase.
1995,
Pubmed
,
Xenbase Hamanaka,
Polo-like kinase is a cell cycle-regulated kinase activated during mitosis.
1995,
Pubmed Hoffmann,
Phosphorylation and activation of human cdc25-C by cdc2--cyclin B and its involvement in the self-amplification of MPF at mitosis.
1993,
Pubmed
,
Xenbase Huang,
Biochemical and biological analysis of Mek1 phosphorylation site mutants.
1995,
Pubmed
,
Xenbase Huchon,
The pure inhibitor of cAMP-dependent protein kinase initiates Xenopus laevis meiotic maturation. A 4-step scheme for meiotic maturation.
1981,
Pubmed
,
Xenbase Izumi,
Phosphorylation and activation of the Xenopus Cdc25 phosphatase in the absence of Cdc2 and Cdk2 kinase activity.
1995,
Pubmed
,
Xenbase Izumi,
Periodic changes in phosphorylation of the Xenopus cdc25 phosphatase regulate its activity.
1992,
Pubmed
,
Xenbase Izumi,
Elimination of cdc2 phosphorylation sites in the cdc25 phosphatase blocks initiation of M-phase.
1993,
Pubmed
,
Xenbase Kotani,
PKA and MPF-activated polo-like kinase regulate anaphase-promoting complex activity and mitosis progression.
1998,
Pubmed Kumagai,
Purification and molecular cloning of Plx1, a Cdc25-regulatory kinase from Xenopus egg extracts.
1996,
Pubmed
,
Xenbase Kumagai,
Regulation of the cdc25 protein during the cell cycle in Xenopus extracts.
1992,
Pubmed
,
Xenbase Kuramochi,
LOK is a novel mouse STE20-like protein kinase that is expressed predominantly in lymphocytes.
1997,
Pubmed Lee,
cdc25+ encodes a protein phosphatase that dephosphorylates p34cdc2.
1992,
Pubmed
,
Xenbase Lee,
Plk is an M-phase-specific protein kinase and interacts with a kinesin-like protein, CHO1/MKLP-1.
1995,
Pubmed Lohka,
Induction of nuclear envelope breakdown, chromosome condensation, and spindle formation in cell-free extracts.
1985,
Pubmed
,
Xenbase Maller,
Recurring themes in oocyte maturation.
1998,
Pubmed Maller,
Progesterone-stimulated meiotic cell division in Xenopus oocytes. Induction by regulatory subunit and inhibition by catalytic subunit of adenosine 3':5'-monophosphate-dependent protein kinase.
1977,
Pubmed
,
Xenbase Matten,
Positive feedback between MAP kinase and Mos during Xenopus oocyte maturation.
1996,
Pubmed
,
Xenbase Mendez,
Phosphorylation of CPE binding factor by Eg2 regulates translation of c-mos mRNA.
2000,
Pubmed
,
Xenbase Morgan,
Principles of CDK regulation.
1995,
Pubmed Nebreda,
Regulation of the meiotic cell cycle in oocytes.
2000,
Pubmed
,
Xenbase Nigg,
Polo-like kinases: positive regulators of cell division from start to finish.
1998,
Pubmed Nishizawa,
Degradation of Mos by the N-terminal proline (Pro2)-dependent ubiquitin pathway on fertilization of Xenopus eggs: possible significance of natural selection for Pro2 in Mos.
1993,
Pubmed
,
Xenbase Norbury,
Animal cell cycles and their control.
1992,
Pubmed Qian,
Purification and cloning of a protein kinase that phosphorylates and activates the polo-like kinase Plx1.
1998,
Pubmed
,
Xenbase Qian,
Mitotic effects of a constitutively active mutant of the Xenopus polo-like kinase Plx1.
1999,
Pubmed
,
Xenbase Qian,
Activated polo-like kinase Plx1 is required at multiple points during mitosis in Xenopus laevis.
1998,
Pubmed
,
Xenbase Roy,
Mos proto-oncogene function during oocyte maturation in Xenopus.
1996,
Pubmed
,
Xenbase Sagata,
The product of the mos proto-oncogene as a candidate "initiator" for oocyte maturation.
1989,
Pubmed
,
Xenbase Sagata,
Introduction: meiotic maturation and arrest in animal oocytes.
1998,
Pubmed Shibuya,
Oncogenic ras triggers the activation of 42-kDa mitogen-activated protein kinase in extracts of quiescent Xenopus oocytes.
1992,
Pubmed
,
Xenbase Smits,
Polo-like kinase-1 is a target of the DNA damage checkpoint.
2000,
Pubmed Tavares,
The conserved mitotic kinase polo is regulated by phosphorylation and has preferred microtubule-associated substrates in Drosophila embryo extracts.
1996,
Pubmed Thomas,
Expression in Escherichia coli and characterization of the heat-stable inhibitor of the cAMP-dependent protein kinase.
1991,
Pubmed VanRenterghem,
Regulation of mitogen-activated protein kinase activation by protein kinases A and C in a cell-free system.
1994,
Pubmed
,
Xenbase Verlhac,
Mos activates MAP kinase in mouse oocytes through two opposite pathways.
2000,
Pubmed Yew,
Meiotic initiation by the mos protein in Xenopus.
1992,
Pubmed
,
Xenbase
