MITOTIC CENTROMERE-ASSOCIATED KINESIN IS IMPORTANT FOR ANAPHASE CHROMOSOME SEGREGATION

Mitotic centromere-associated kinesin (MCAK) is recruited to the centr omere at prophase and remains centromere associated until after teloph ase. MCAK is a homodimer that is encoded by a single gene and has no a ssociated subunits. A motorless version of MCAK that binds centromeres but not microtubules disrupts chromosome segregation during anaphase, Antisense-induced depletion of MCAK re suits in the same defect. MCAK overexpression induces centromere-independent bundling and eventual l oss of spindle microtubule polymer suggesting that centromere-associat ed bundling and/or depolymerization activity is required for anaphase, Live cell imaging indicates that MCAK may be required to coordinate t he onset of sister centromere separation.