Control of Cyclin Ubiquitination by CDK-Regulated Binding of Hct1 to the Anaphase Promoting Complex
Wolfgang Zachariae,
*
Michael Schwab,
*
Kim Nasmyth,
Wolfgang Seufert
Proteolysis of mitotic cyclins depends on a multisubunit
ubiquitin-protein ligase, the anaphase promoting complex (APC).
Proteolysis commences during anaphase, persisting throughout
G1 until it is terminated by cyclin-dependent kinases
(CDKs) as cells enter S phase. Proteolysis of mitotic cyclins in yeast
was shown to require association of the APC with the substrate-specific
activator Hct1 (also called Cdh1). Phosphorylation of Hct1
by CDKs blocked the Hct1-APC interaction. The mutual inhibition between
APC and CDKs explains how cells suppress mitotic CDK activity during
G1 and then establish a period with elevated kinase
activity from S phase until anaphase.
W. Zachariae and K. Nasmyth, Research Institute of Molecular
Pathology, Dr. Bohr-Gasse 7, A-1030 Vienna, Austria. M. Schwab and W. Seufert, Institute of Industrial Genetics, University of Stuttgart,
Allmandring 31, D-70569 Stuttgart, Germany.
*
These authors contributed equally to this work.
To whom correspondence should be addressed. E-mail:
wolfgang.seufert{at}po.uni-stuttgart.de
