The p34 kinase is a highly regulated serinethreonine kinase that when complexed with cyclins A and B, controls cell entry Into mitosis. Recently, premature activation of p34 was shown to be required for apoptosis induced by a wide variety of agents. Here, we show that Taxol induced p34 kinase activity with a peak at 6 h In human breast carcinoma MCF-7 cells. We subsequently observed that the ac...

The protein kinase inhibitor 2-aminopurine induces checkpoint override and mitotic exit in BHK cells which have been arrested in mitosis by inhibitors of microtubule function (Andreassen, P. R., and R. L. Margolis. 1991. J. Cell Sci. 100:299-310). Mitotic exit is monitored by loss of MPM-2 antigen, by the reformation of nuclei, and by the extinction of p34 ~c2dependent H1 kinase activity. 2-AP-...

At any point during the progression of many tumor types, cells can develop a hyperploid DNA content. Hyperploid tumors are significant more aggressive, with a higher growth rate and a poor patient prognosis. Yeast genetics have implicated three important genes involved in DNA ploidy changes: cdc2, cyclin b, and a specific inhibitor of the p34(cdc2)/cyclin B kinase, rum1. Mutations in these gene...

In an effort to shed light upon the processes of ant itunior drug-induced cell death, we have carried out a systematic study of the effects of the anti-topoisomerase II agent, etoposide, on Chinese hamster ovary cells. Treatment of Chinese hamster ovary cells for l h with a 2-log cell-killing concentration of etoposide induces a high incidence of DNA single-strand breaks which are rapidly repai...

At any point during the progression of many tumor types, cells can develop a hyperploid DNA conteni Hyperploid tumors are signiflcantiy more aggressive, with a higher growth rate and a poor patient prognosis. Yeast genetics have implicated three important genes Involved in DNA ploidy changes: cdc2, cycin b, and a specific inhibiter of the p34@2/cyc1in B kinase, rumi. Mutations in these genes un...

The Arp2/3 protein complex has been implicated in the control of actin polymerization in cells. The human complex consists of seven subunits which include the actin related proteins Arp2 and Arp3, and five others referred to as p41-Arc, p34-Arc, p21-Arc, p20-Arc, and p16-Arc (p omplex). We have determined the predicted amino acid sequence of all seven subunits. Each has homologues in diverse eu...

Murine erythroleukemia (MEL) cells were exposed to a high pressure of 80 MPa or aphidicolin (APH), DNA polymerase inhibitor. The effects of caffeine on cell cycle were examined using these cells. During the culture of 80 MPa-treated MEL cells at atmospheric pressure, the cells arrested in the G2 phase, and cyclin B and hyperphosphorylated p34(cdc2) were accumulated. Namely, maturation promoting...