Modeling the Budding Yeast Cell Cycle


Activator of APC-dependent proteolysis (Morgan, 1999; Zachariae & Nasmyth, 1999). Cdh1 (Hct1) plays an important role in Clb2 degradation during telophase (Baumer et al., 2000; Yeong et al., 2000). Null mutants are viable (Schwab et al., 1997).


Cdh1 is a protein related to Cdc20 (Visintin et al., 1997). It binds with APC and is needed for degradation of Clb2 and proteins such as spindle associated protein Ase1 (Visintin et al., 1997), polo-like protein Cdc5 (Schwab et al., 1997), and maybe Cdc20 itself (Pfleger & Kirschner, 2000).


mRNA and protein levels do not fluctuate significantly during the cell cycle (Zachariae et al., 1998, Prinz et al., 1998; Jaspersen et al., 1999).


The association of Cdh1 and APC is cell cycle regulated through phosphorylation and dephosphorylation of Cdh1. When Cdh1 is phosphorylated by the CDKs, the binding with APC is inhibited (Amon, 1997; Jaspersen et al., 1999; Zachariae et al., 1998). When Cdc14 activates, it reverses the CDK-mediated phosphorylation and promotes APC binding (Jaspersen et al., 1999; Visintin et al., 1997).