October 22 @ 11:00 am – 12:00 pm
David Morgan, Associate Investigator, Department of Molecular Integrative Physiology
University of California, San Francisco
“Biochemical Mechanisms of Chromosome Segregation“
We study the mechanisms that govern progression through mitosis, with an emphasis on the complex docking interactions that mediate specific substrate binding to cell cycle enzymes. These efforts have focused recently on separase, the protease that initiates chromosome separation in anaphase by cleaving a subunit of the cohesin complex. In collaboration with the structural biologist Andreas Boland, we studied how separase interacts with short sequence motifs on its cohesin substrate, and we explored the mechanisms underlying the control of separase by inhibitor proteins securin and cyclin B. These studies led to the identification of a phosphate-binding site on cyclin B, which we showed is an important docking site for mitotic substrates of the cyclin-dependent kinases.