SUMMARY PARAGRAPH for CDH1
CDH1 is an activator of the anaphase-promoting complex (APC), an E3 ubiquitin ligase in the ubiquitin-mediated proteolysis pathway (5). The APC ubiquitin ligase helps regulate the metaphase/anaphase transition and exit from mitosis/G1 entry through ubiquitination of various substrates. These include mitotic cyclins, the sister chromatid separation inhibitor Pds1p, the Kip1p and Cin8p motor proteins, Cdc5p, and the spindle disassemblyfactor, Ase1p (6, 7, 8, 9, 10, 11).
Deletion of Cdh1 results in slow growth and the accumulation of very large amounts of Clb2p and Ase1p (1). Further analysis of the mutants demonstrated that Cdh1p regulates the activity and substrate specificity of the APC (1). It serves as an activator of the APC and mediates ubiquitin-dependent protein degradation of the mitotic cyclin Clb2p, the polo kinase Cdc5p, and the spindle protein Ase1p during anaphase of the cell cycle (2, 1, 12).
The level of Cdh1p remains constant throughout the cell cycle, however it only binds the APC during G1. For the rest of the cell cycle, the association of Cdh1p with the APC is inhibited due to its phosphorylation by the kinase Cdc28p (13, 14).
CDH1 is a homolog of CDC20, another APC activator (1). CDH1 orthologs have been identified in various species including worms, flies and humans (15, 5, 1).
Last updated: 2005-05-11