Dr. Tim Hayes

My research interests center on the molecular mechanisms involved in the permanent exit of cells from the cell cycle as they terminally differentiate.  Cells that previously proliferated in response to external signals now respond to those same signals in a different way.  What changes in the cell to alter its response?

The major project in my lab looks at this question using the terminal differentiation of pre-adipocytes as a model.  Pre-adipocytes proliferate rapidly and can be cultured in the lab.  When they are contact inhibited they can be treated with a cocktail of hormones and will respond by differentiating.  Over the course of the next 4 days they express fat cell proteins, produce lipid droplets and turn into adipocytes.  During this time many of the cells divide once or twice but once this period is past they are post-mitotic- they never divide again.

My lab is working on the role of the Retinoblastoma-related proteins p107 and p130 during the first 24 hours of this process.  My lab is working on experiments designed to identify the proteins to which p107 and p130 bind, based on the assumption that they act through relatively stable interactions with other proteins, similar to the retinoblastoma protein pRB.  Our experiments utilize cell culture, protein techniques (chromatography, immunoprecipitation, DNA-binding assays, electrophoresis, Western blotting, etc.) and molecular biology techniques (transfection, mRNA isolation, PCR, etc.) as required by the particular question being asked.