Michael Bagdasarian, M.D., Ph.D.

bagdasa3@msu.edu

Research

• Understanding of the mechanisms of protein secretion across the outer membrane of gram-negative bacteria.
• Contribution of protein secretion to pathogenesis of bacteria.

Gram-negative bacteria secrete proteins via several different pathways.

Type 2 secretion pathway known as Type 2 Secretion System (T2SS) transports folded and assembled proteins, such as cholera toxin and other virulence proteins, across the outer membrane into the extracellular medium. T2SS is composed of 12 to 15 different proteins which form large assemblies spanning both cytoplasmic and the outer membranes.

The research methods used by us to study T2SS in Vibrio cholerae are: molecular biology of the genes essential for the process of secretion; purification and study of the membrane proteins essential for secretion; their location in the subcellular compartment; their interaction with one another and with the proteins to be secreted, the relation of their structure to function.

T2SS is present in many gram-negative bacteria. The contribution of this secretion pathway to pathogenesis is being studied presently in pathogenic E. coli and in Yersinia.