Mitotic checkpoint inactivation at anaphase onset

摘要: The mitotic checkpoint prevents chromosome segregation until all chromosomes have reached bi-polar orientation and come under tension on the spindle. Once this is achieved, protease separase activated to cleave chromosomal cohesin complex trigger anaphase. Cohesin cleavage releases between sister chromatids, however fails respond apparent tension defect. aim of study was understand why mitotic checkpoint remains silent when sisters lose due cohesin cleavage in anaphase. We showed budding yeast that loss chromatid cohesion at anaphase onset could re-activate checkpoint. This is normally prevented by separase-dependent activation Cdc14 phosphatase. Cdc14 turn downregulates by dephosphorylation Sli15/INCENP, part conserved Aurora B kinase proposed sensor at kinetochores. Consequent relocation Sli15/INCENP from centromeres central spindle during a distinctive feature B kinase complex. Our results imply existence mechanism of mitotic inactivation anaphase. Dephosphorylation of Sli15/INCENP its spatial separation kinetochores prevent the checkpoint re-engaging chromatids is lost