Suprynowicz FA et al. (1994), Ca2+ triggers premature inactivation of the cdc...

ECB-ART-35934

Proc Natl Acad Sci U S A 1994 Jun 21;9113:6176-80. doi: 10.1073/pnas.91.13.6176.

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Ca2+ triggers premature inactivation of the cdc2 protein kinase in permeabilized sea urchin embryos.

Suprynowicz FA , Prusmack C , Whalley T .

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Exit from mitosis requires inactivation of the cyclin B-p34cdc2 protein kinase complex. Since increased cytosolic Ca2+ has been implicated as a potential trigger of mitotic progression, we directly tested the possibility that Ca2+ triggers the pathway responsible for inactivating the cdc2 kinase, using sea urchin embryos permeabilized at various stages of the cell cycle. In cells permeabilized during late interphase and prophase, micromolar Ca2+ induced premature inactivation of the cdc2 kinase without affecting the absolute amount of p34cdc2 protein. Inactivation was selective for the cdc2 kinase, as elevated Ca2+ had no effect on cAMP-dependent protein kinase activity. Premature cdc2 kinase inactivation did not require cyclin B destruction, but did coincide with the dissociation of cyclin B-p34cdc2 complexes. In cells permeabilized during prometaphase and metaphase, cdc2 kinase inactivation was Ca(2+)-independent, presumably because at these later times the inactivating pathway had been enabled prior to permeabilization. This work provides evidence that Ca2+ is the physiological trigger enabling cdc2 kinase inactivation during mitosis.

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Genes referenced: LOC100887844 LOC115919910 LOC576114 LOC586799 LOC593358

References [+] :

Bradford, A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. 1976, Pubmed