A role for cAMP-dependent protein kinase in early embryonic divisions.
basic_science · Level V
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- Record sourced from PubMed, PMID 7937913.
- Also identified by PMC identifier 44924.
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Abstract
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.
Medical subject headings
- CDC2 Protein Kinase
- Cell Cycle
- Cell Division
- Cyclic AMP-Dependent Protein Kinases
- Cyclins
- Oocytes