Sebastian Poggio, Ph.D.

Research

Protein folding is critically important for all life from microbes to man. Cellular polarity is a basic biological process required for differential cellular organization and cell differentiation. In bacteria, cell polarity can be observed in many different ways; protein localization, membrane stability and composition, chromosomal organization, among others. One of the oldest known determinants of polarity in rod shaped bacteria is the highly stable peptidoglycan cell wall. Following identification of a set of proteins with peptidoglycan binding domains present in the genome sequence of Caulobacter crescentus, we used site directed mutagenesis to generate a mutant that shows aberrant polar growth, suggesting that the stability of the polar cell wall has been lost. The localization pattern of this protein during the cell cycle indicates that this protein is active during early cell division. From analyses we performed, in which we truncated the peptidoglycan binding regions, we have shown that the peptidoglycan binding regions are required for its localization. Interestingly, this protein also seems to possess enzymatic activity that could in principle be responsible for modifying the way in which the polar cell wall is generated during division. We are currently investigating this possibility.