Format

Send to

Choose Destination
See comment in PubMed Commons below
Curr Biol. 1998 Apr 23;8(9):497-507.

The Polo-related kinase Cdc5 activates and is destroyed by the mitotic cyclin destruction machinery in S. cerevisiae.

Author information

1
Department of Physiology, University of California San Francisco, California, 94143, USA.

Abstract

BACKGROUND:

Following chromosome segregation in anaphase, ubiquitin-dependent degradation of mitotic cyclins contributes to the exit from mitosis. A key step in this process is catalyzed by a ubiquitin-protein ligase known as the anaphase-promoting complex (APC), the regulation of which is poorly understood. The Polo-related protein kinase Cdc5 in Saccharomyces cerevisiae might encode a regulator of the APC, because cdc5 mutant cells arrest with a late mitotic phenotype similar to that observed in cells with defective cyclin destruction.

RESULTS:

We investigated the role of Cdc5 in the regulation of mitotic cyclin degradation. In cdc5-1 mutant cells, we observed a defect in the destruction of cyclins and a reduction in the cyclin-ubiquitin ligase activity of the APC. Overexpression of CDC5 resulted in increased APC activity and mitotic cyclin destruction in asynchronous cells or in cells arrested in metaphase. CDC5 mutation or overexpression did not affect the degradation of the APC substrate Pds 1, which is normally degraded at the metaphase-to-anaphase transition. Cyclin-specific APC activity in cells overexpressing CDC5 was reduced in the absence of the APC regulatory proteins Hct 1 and Cdc20. In G1, Cdc5 itself was degraded by an APC-dependent and Hct1-dependent mechanism.

CONCLUSIONS:

We conclude that Cdc5 is a positive regulator of cyclin-specific APC activity in late mitosis. Degradation of Cdc5 in G1 might provide a feedback mechanism by which the APC destroys its activator at the onset of the next cell cycle.

PMID:
9560342
[Indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

0 comments

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Support Center