Harris Bernstein is a Senior Investigator in the Genetics and Biochemistry Branch,National Institute of Diabetes and Digestive Diseases,National Institutes of Health (NIH} in Bethesda,Maryland. He received an undergraduate degree from Harvard University and a Ph.D. from MIT. Dr. Bernstein has a long-standing interest in understanding how proteins are translocated across or inserted into the membranes of both pathogenic and non-pathogenic bacteria. As a post-doctoral fellow in Peter Walter’s lab at the University of California at San Francisco he discovered a bacterial homolog of the signal recognition particle (SRP},an essential protein targeting factor that at the time was believed to exist only in mammalian cells. As an independent investigator at the NIH he continued to work on SRP and the Sec pathway in E. coli. He and his colleagues have also investigated the mechanism by which the expression of secA is regulated at the level of translation by ribosome stalling. His research group currently studies the assembly of bacterial outer membrane proteins and the secretion of virulence factors by a specialized pathway (the type V or “autotransporter” pathway} that is utilized by a wide variety of Gram-negative pathogens. Recently his group has also begun to investigate protein secretion in Bacteroides fragilis,a prominent member of the human gut microbiome.