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???
M-phase entry in eukaryotic cells is driven by activation of MPF, a regulatory factor composed of cyclin B and the protein kinase p34(cdc2). In G2-arrested Xenopus oocytes, there is a stock of p34(cdc2)/cyclin B complexes (pre-MPF) which is maintained in an inactive state by p34(cdc2) phosphorylation on Thr14 and Tyr15. This suggests an important role for the p34(cdc2) inhibitory kinase(s) such as Wee1 and Myt1 in regulating the G2-->M transition during oocyte maturation. MAP kinase (MAPK) activation is required for M-phase entry in Xenopus oocytes, but its precise contribution to the activation of pre-MPF is unknown. Here we show that the C-terminal regulatory domain of Myt1 specifically binds to p90(rsk), a protein kinase that can be phosphorylated and activated by MAPK. p90(rsk) in turn phosphorylates the C-terminus of Myt1 and down-regulates its inhibitory activity on p34(cdc2)/cyclin B in vitro. Consistent with these results, Myt1 becomes phosphorylated during oocyte maturation, and activation of the MAPK-p90(rsk) cascade can trigger some Myt1 phosphorylation prior to pre-MPF activation. We found that Myt1 preferentially associates with hyperphosphorylated p90(rsk), and complexes can be detected in immunoprecipitates from mature oocytes. Our results suggest that during oocyte maturation MAPK activates p90(rsk) and that p90(rsk) in turn down-regulates Myt1, leading to the activation of p34(cdc2)/cyclin B.
Abrieu,
Mitogen-activated protein kinase activation down-regulates a mechanism that inactivates cyclin B-cdc2 kinase in G2-arrested oocytes.
1997, Pubmed,
Xenbase
Abrieu,
Mitogen-activated protein kinase activation down-regulates a mechanism that inactivates cyclin B-cdc2 kinase in G2-arrested oocytes.
1997,
Pubmed
,
Xenbase
Alcorta,
Sequence and expression of chicken and mouse rsk: homologs of Xenopus laevis ribosomal S6 kinase.
1989,
Pubmed
,
Xenbase
Alessi,
PD 098059 is a specific inhibitor of the activation of mitogen-activated protein kinase kinase in vitro and in vivo.
1995,
Pubmed
Alessi,
The protein kinase C inhibitors Ro 318220 and GF 109203X are equally potent inhibitors of MAPKAP kinase-1beta (Rsk-2) and p70 S6 kinase.
1997,
Pubmed
Atherton-Fessler,
Cell cycle regulation of the p34cdc2 inhibitory kinases.
1994,
Pubmed
,
Xenbase
Barkoff,
Meiotic maturation in Xenopus requires polyadenylation of multiple mRNAs.
1998,
Pubmed
,
Xenbase
Booher,
Human Myt1 is a cell cycle-regulated kinase that inhibits Cdc2 but not Cdk2 activity.
1997,
Pubmed
,
Xenbase
Chung,
Mitogen-activated Swiss mouse 3T3 RSK kinases I and II are related to pp44mpk from sea star oocytes and participate in the regulation of pp90rsk activity.
1991,
Pubmed
Coleman,
Cdc2 regulatory factors.
1994,
Pubmed
Cyert,
Regulation of MPF activity in vitro.
1988,
Pubmed
,
Xenbase
Dunphy,
The cdc25 protein contains an intrinsic phosphatase activity.
1991,
Pubmed
Erikson,
Purification and characterization of a protein kinase from Xenopus eggs highly specific for ribosomal protein S6.
1986,
Pubmed
,
Xenbase
Fisher,
Evidence for two catalytically active kinase domains in pp90rsk.
1996,
Pubmed
Gautier,
Cyclin B in Xenopus oocytes: implications for the mechanism of pre-MPF activation.
1991,
Pubmed
,
Xenbase
Gautier,
cdc25 is a specific tyrosine phosphatase that directly activates p34cdc2.
1991,
Pubmed
,
Xenbase
Gotoh,
Initiation of Xenopus oocyte maturation by activation of the mitogen-activated protein kinase cascade.
1995,
Pubmed
,
Xenbase
Haccard,
Induction of Xenopus oocyte meiotic maturation by MAP kinase.
1995,
Pubmed
,
Xenbase
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
Howell,
XSmad2 directly activates the activin-inducible, dorsal mesoderm gene XFKH1 in Xenopus embryos.
1997,
Pubmed
,
Xenbase
Hsiao,
Evidence that inactive p42 mitogen-activated protein kinase and inactive Rsk exist as a heterodimer in vivo.
1994,
Pubmed
,
Xenbase
Huang,
Biochemical and biological analysis of Mek1 phosphorylation site mutants.
1995,
Pubmed
,
Xenbase
Izumi,
Elimination of cdc2 phosphorylation sites in the cdc25 phosphatase blocks initiation of M-phase.
1993,
Pubmed
,
Xenbase
Izumi,
Periodic changes in phosphorylation of the Xenopus cdc25 phosphatase regulate its activity.
1992,
Pubmed
,
Xenbase
Jones,
A Xenopus ribosomal protein S6 kinase has two apparent kinase domains that are each similar to distinct protein kinases.
1988,
Pubmed
,
Xenbase
Kamps,
Determination of phosphoamino acid composition by acid hydrolysis of protein blotted to Immobilon.
1991,
Pubmed
Kanki,
Progression from meiosis I to meiosis II in Xenopus oocytes requires de novo translation of the mosxe protooncogene.
1991,
Pubmed
,
Xenbase
Kobayashi,
On the synthesis and destruction of A- and B-type cyclins during oogenesis and meiotic maturation in Xenopus laevis.
1991,
Pubmed
,
Xenbase
Kornbluth,
Membrane localization of the kinase which phosphorylates p34cdc2 on threonine 14.
1994,
Pubmed
,
Xenbase
Kosako,
Requirement for the MAP kinase kinase/MAP kinase cascade in Xenopus oocyte maturation.
1994,
Pubmed
,
Xenbase
Kumagai,
The cdc25 protein controls tyrosine dephosphorylation of the cdc2 protein in a cell-free system.
1991,
Pubmed
,
Xenbase
Kumagai,
Regulation of the cdc25 protein during the cell cycle in Xenopus extracts.
1992,
Pubmed
,
Xenbase
Kumagai,
Purification and molecular cloning of Plx1, a Cdc25-regulatory kinase from Xenopus egg extracts.
1996,
Pubmed
,
Xenbase
Kumagai,
Regulation of Xenopus Cdc25 protein.
1997,
Pubmed
,
Xenbase
Leevers,
Activation of extracellular signal-regulated kinase, ERK2, by p21ras oncoprotein.
1992,
Pubmed
Leighton,
Comparison of the specificities of p70 S6 kinase and MAPKAP kinase-1 identifies a relatively specific substrate for p70 S6 kinase: the N-terminal kinase domain of MAPKAP kinase-1 is essential for peptide phosphorylation.
1995,
Pubmed
Lew,
Regulatory roles of cyclin dependent kinase phosphorylation in cell cycle control.
1996,
Pubmed
Liu,
The human Myt1 kinase preferentially phosphorylates Cdc2 on threonine 14 and localizes to the endoplasmic reticulum and Golgi complex.
1997,
Pubmed
,
Xenbase
Masui,
Cytoplasmic control of nuclear behavior during meiotic maturation of frog oocytes.
1971,
Pubmed
Masui,
Oocyte maturation.
1979,
Pubmed
McGowan,
Human Wee1 kinase inhibits cell division by phosphorylating p34cdc2 exclusively on Tyr15.
1993,
Pubmed
McGowan,
Cell cycle regulation of human WEE1.
1995,
Pubmed
Morgan,
Principles of CDK regulation.
1995,
Pubmed
Mueller,
Cell cycle regulation of a Xenopus Wee1-like kinase.
1995,
Pubmed
,
Xenbase
Mueller,
Myt1: a membrane-associated inhibitory kinase that phosphorylates Cdc2 on both threonine-14 and tyrosine-15.
1995,
Pubmed
,
Xenbase
Murakami,
Analysis of the early embryonic cell cycles of Xenopus; regulation of cell cycle length by Xe-wee1 and Mos.
1998,
Pubmed
,
Xenbase
Murray,
Cell cycle extracts.
1991,
Pubmed
Nebreda,
The c-mos proto-oncogene protein kinase turns on and maintains the activity of MAP kinase, but not MPF, in cell-free extracts of Xenopus oocytes and eggs.
1993,
Pubmed
,
Xenbase
Nebreda,
The protein kinase mos activates MAP kinase kinase in vitro and stimulates the MAP kinase pathway in mammalian somatic cells in vivo.
1993,
Pubmed
,
Xenbase
Nebreda,
Newly synthesized protein(s) must associate with p34cdc2 to activate MAP kinase and MPF during progesterone-induced maturation of Xenopus oocytes.
1995,
Pubmed
,
Xenbase
Nebreda,
p21ras-induced meiotic maturation of Xenopus oocytes in the absence of protein synthesis: MPF activation is preceded by activation of MAP and S6 kinases.
1993,
Pubmed
,
Xenbase
Parker,
Inactivation of the p34cdc2-cyclin B complex by the human WEE1 tyrosine kinase.
1992,
Pubmed
Peverali,
Phosphorylation of Drosophila Jun by the MAP kinase rolled regulates photoreceptor differentiation.
1996,
Pubmed
Posada,
Mos stimulates MAP kinase in Xenopus oocytes and activates a MAP kinase kinase in vitro.
1993,
Pubmed
,
Xenbase
Sagata,
Function of c-mos proto-oncogene product in meiotic maturation in Xenopus oocytes.
1988,
Pubmed
,
Xenbase
Sagata,
The product of the mos proto-oncogene as a candidate "initiator" for oocyte maturation.
1989,
Pubmed
,
Xenbase
Sheets,
Polyadenylation of c-mos mRNA as a control point in Xenopus meiotic maturation.
1995,
Pubmed
,
Xenbase
Shibuya,
Mos induces the in vitro activation of mitogen-activated protein kinases in lysates of frog oocytes and mammalian somatic cells.
1993,
Pubmed
,
Xenbase
Stokoe,
MAPKAP kinase-2; a novel protein kinase activated by mitogen-activated protein kinase.
1992,
Pubmed
Strausfeld,
Dephosphorylation and activation of a p34cdc2/cyclin B complex in vitro by human CDC25 protein.
1991,
Pubmed
Sturgill,
Insulin-stimulated MAP-2 kinase phosphorylates and activates ribosomal protein S6 kinase II.
1988,
Pubmed
,
Xenbase
Tang,
Two distinct mechanisms for negative regulation of the Wee1 protein kinase.
1993,
Pubmed
,
Xenbase
Zhao,
Regulation and interaction of pp90(rsk) isoforms with mitogen-activated protein kinases.
1996,
Pubmed
