Characterization of the assembly of type III secretion system of pathogenic Escherichia coli

The type 3 secretion system (T3SS) is a multi-protein complex that plays a central role in the virulence of many bacteria categorized as Gram-negative. Gram-negative bacteria include some of the most harmful bacteria to humans and plants. T3SS directs the secretion and transfer of bacterial proteins into the cytoplasm – the portion of the cell outside the nucleus of eukaryotic cells. It’s known that the secretion system is composed of about 20 to 25 different proteins arranged into two distinct parts called the needle complex and the translocon. However, the exact mechanisms of how proteins are secreted by T3SS and the precise molecular organization of the complex are poorly understood. Dr. Neta Wexler Sal-Man aims to define, at the molecular level, the interactions of proteins that create the secretion apparatus of two pathogenic bacteria: Enteropathogenic E. coli and enterohemorrhagic E. coli. In the long term, she hopes to identify a way to manipulate the secretion system in order to inject desired proteins or molecules into eukaryotic cells. The research will help improve understanding of this highly complex type 3 secretion system and could ultimately contribute to the design of new therapeutic drugs aimed at the potentially deadly bacteria that use T3SS.