Charles Holmes

Research:

Reversible protein phosphorylation is a principal mechanism by which intracellular signal transduction is linked to external stimuli in eukaryotes. Phosphorylation of any protein depends upon the relative activities of protein kinases and phosphatases. The latter enzymes are emerging as important regulatory enzymes with key roles in mediating hormone/growth factor action, tumor suppression and cell division. Our work is directed primarily at understanding how protein phosphatases are regulated at the molecular level. Two major systems are being studied: (i) Regulation of protein phosphatases by inhibitor proteins, cyclic peptide toxins and tumor promoting marine toxins and (ii) Marine phytoplankton as a model system for studying signal transduction pathways involving protein phosphatases and protein kinases.

Our laboratory is well equipped with HPLC, FPLC, capillary electrophoresis and facilities for molecular biology. We also collaborate extensively on structural biology aspects of our research program with several international groups in the field