A role for cAMP-dependent protein kinase in early embryonic divisions.
AUTOR(ES)
Grieco, D
RESUMO
The cAMP-dependent protein kinase (PKA) pathway affects cell cycle progression in "cycling" Xenopus egg extracts. The concentration of free PKA catalytic subunit oscillates during the cell cycle with a peak at the mitosis-interphase transition and a minimum at the onset of mitosis. Inhibition of endogenous PKA in interphase hastens the onset of mitosis. Stimulation of PKA induces interphase arrest, preventing the activation of the M-phase-promoting factor. PKA does not block the accumulation of cyclin or its binding to p34cdc2, but the resultant complex lacks kinase activity and p34cdc2 remains tyrosine-phosphorylated. PKA appears to stimulate an okadaic acid-sensitive serine/threonine phosphatase that acts upon cdc25. In this way PKA could downregulate the p34cdc2 tyrosine phosphatase activity of cdc25 and consequently block the activation of the M-phase-promoting factor.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=44924Documentos Relacionados
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