Identification of mitotic (CDC2) and interphase histone H1 kinases by nondenaturing gel electrophoresis and peptide assays

CDC2 kinase activity was decreased by up to 75% when mitotic cell free extracts from mouse fibroblasts were incubated with cAMP and ATP. This effect was blocked by PKI, the heat stable inhibitor of cAMP-dependent protein kinase (PKA). An acidic, heat stable protein from G1 cells, consistent with inhibitor-1 of protein phosphatase 1, mimicked the effect of cAMP, but was not antagonized by PKI. Okadaic acid, another inhibitor of protein phosphatase 1, also downregulated CD2 activity, and the effect was independent of both cAMP and PKI. The evidence suggests that PKA exerts its effect by activating inhibitor-1 by phosphorylation, and that the next step in the regulatory pathway requires the inactivation of one or more protein phosphatase 1 isoenzymes. Non-denaturing gel electrophoresis suggested that the size and/or charge density of the CDC2 kinase complex was changed when the activity was downregulated by cAMP or G1 extracts.

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Protein kinase cascades in meiotic and mitotic cell cycle control

Pelech

Sanghera²,

Daya-Makin³

1990

Biochem. Cell Biol.

120

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Eukaryotic cell cycle progression during meiosis and mitosis is extensively regulated by reversible protein phosphorylation. Many cell surface receptors for mitogens are ligand-stimulated protein-tyrosine kinases that control the activation of a network of cytoplasmic and nuclear protein-serine (threonine) kinases. Over 30 plasma membrane associated protein-tyrosine kinases are encoded by proto-oncogenes, i.e., genes that have the potential to facilitate cancer when disregulated. Proteins such as ribosomal protein S6, microtubule-associated protein-2, myelin basic protein, and casein have been used to detect intracellular protein-serine (threonine) kinases that are activated further downstream in growth factor signalling transduction cascades. Genetic analysis of yeast cell division control (cdc) mutants has revealed another 20 or so protein-serine (threonine) kinases. One of these, specified by the cdc-2 gene in Schizosaccharomyces pombe, has homologs that are stimulated during M phase in maturing sea star and frog oocytes and mammalian somatic cells. Furthermore, during meiotic maturation in these echinoderm and amphibian oocytes, this is followed by activation of many of the same protein-serine (threonine) kinases that are stimulated when quiescent mammalian somatic cells are prompted with mitogens to traverse from G0 to G1 phase. These findings imply that a similar protein kinase cascade may oversee progression at multiple points in the cell cycle.

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Identification of mitotic (CDC2) and interphase histone H1 kinases by nondenaturing gel electrophoresis and peptide assays

Cited by 3 publications

References 17 publications

[10] Design and use of peptide substrates for protein kinases

[10] Design and use of peptide substrates for protein kinases

Mitotic CDC2 kinase is negatively regulated by cAMP‐dependent protein kinase in mouse fibroblast cell free extracts

Protein kinase cascades in meiotic and mitotic cell cycle control

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