Requirements and reasons for effective inhibition of the anaphase promoting complex activator CDH1.

ABSTRACT: Anaphase promoting complex (APC)-Cdh1 targets multiple mitotic proteins for degradation upon exit from mitosis into G1; inhibitory phosphorylation of Cdh1 by cyclin-dependent kinase (CDK) and Polo kinase has been proposed to prevent the premature degradation of substrates in the ensuing cell cycle. Here, we demonstrate essentiality of CDK phosphorylation of Cdh1 in Saccharomyces cerevisiae by exact endogenous gene replacement of CDH1 with CDK-unphosphorylatable CDH1-m11; in contrast, neither Cdh1 polo kinase sites nor polo interaction motifs are required. CDH1-m11 cells arrest in the first cycle with replicated DNA and sustained polarized growth; most cells have monopolar spindles. Blocking proteolysis of the Cin8 kinesin in CDH1-m11 cells does not promote spindle pole body (SPB) separatio

SUBMITTER: Robbins JA 

PROVIDER: S-EPMC2836972 | biostudies-literature | 2010 Mar

REPOSITORIES: biostudies-literature