Dr. Lucy Robinson's Research Focus

Major Research Interests:
Control of cell growth and division; protein phosphorylation and vesicular trafficking; yeast genetics.

Protein phosphorylation is a major post-translational regulatory mechanism in eukaryotic cells. Numerous protein kinases influence diverse aspects of cell growth and division, differentiation, and environmental adaptation. The activities of these protein kinases are often linked in cascades in which activation of a protein kinase is itself accomplished by phosphorylation. This can result in a response system that is sensitive to multiple input signals and can correlate levels of response with varying levels of signal. Our laboratory focuses on the biological activities of a yeast protein kinase (Yck=yeast casein kinase I) that is ideally suited to participate in phosphorylation cascades. Casein kinase I (CK1) proteins recognize a serine or threonine in an acidic context and can act on substrate sites in which the acidic moiety is a phosphorylated residue. Therefore, phosphorylation by these protein kinases can be targeted by a previous phosphorylation event. Five CK1 isoforms have been identified in mammalian cells. We identified the Yck CK1 isoform, one of three in yeast, by its effects on cellular responses to environmental stress. Our research is directed toward identifying the biological roles, targets, and regulation of the Yck proteins. Yck activity is essential to yeast cell viability, and examination of a conditional yck- mutant indicates that there are multiple cellular pathways requiring Yck activity. Current projects concern the roles of the Yck proteins in protein trafficking and cellular morphogenesis and the mechanisms of modification and targeting of Yck2 protein.