Departmental Seminar: Dr. Peter Chien

Event Date: 12.15.2014 Day: Monday Time: 12:00 pm Location: 601 Fairchild Event Type: Departmental

Department of Biochemistry and Molecular Biology
University of Massachusetts Amherst

Title: "Regulated protein degradation during a bacterial cell cycle"

Abstract:

Energy dependent protein degradation ensures the complete and immediate destruction of undesired proteins with stringent selectivity. Regulated protein degradation is crucial for normal cellular growth and development as well during responses to environmental stress. In the bacteria Caulobacter crescentus the essential AAA+ protease ClpXP coordinates replication with differentiation via regulated proteolysis of key cell cycle factors. Using a substrate trapping approach, we have identified several new pathways that are regulated through proteolysis and revealed new features of protein degradation, such as an essential role for partial processing to generate active fragments of replication machines. We have also discovered new substrates that are selectively degraded during the bacterial cell cycle. Cell cycle proteolysis by the ClpXP protease requires several additional cellular factors but how these factors influence substrate choice is poorly understood due to a lack of biochemical data. I will present our work reconstituting this process using highly purified proteins to illustrate how these additional factors alter protease selectivity by hierarchically assembling into adaptor hubs. These complexes provide highly tuned substrate recognition by using a modular design that lends itself to the diverse protease activity seen throughout bacteria.