Black Spot, Black Death, Black Pearl: Tales of Bacterial Pathogens

My lab is interested in elucidating the activity of virulence factors from pathogenic bacteria so that we can gain novel molecular insights into eukaryotic signaling systems. The marine bacterium Vibrio parahaemolyticus is the worldwide leading cause of seafood-borne acute gastroenteritis. We are working on the two V. parahaemolyticus type 3 secretion systems (T3SS1 and T3SS2) and their bacterial effectors to understand how signaling systems in the eukaryotic host can be manipulated by these bacterial pathogens. Each of the two T3SSs uses a unique repertoire of effectors to manipulate host signaling. The first T3SS1 is thought to be used to maintain V. parahaemolyticus’ survival in the environment, while the second T3SS2 is used for pathogenesis in an animal host. For decades, this pathogen has been studied exclusively as an extracellular bacterium, however, our studies demonstrated that V. parahaemolyticus invades and proliferate within host cells using the second T3SS2. What is somewhat perplexing is how the innate immune response is manipulated by this pathogen. Our ongoing studies have elucidated redundant and surprising mechanisms used to subvert detection during invasion and replication inside host cells. This work at UT Southwestern is accomplished using a broad range of tools, including biochemistry, molecular microbiology, protein chemistry, structural biology, yeast genetics, cell biology and more.

Speaker: Kim Orth, US Southwestern Medical Center