Dr. Lauren Brandon
Assistant Professor of Biology
Mississippi University for Women
Office: 662-329-7378

Protein Localization

Abstract: My research project mainly focuses on asymmetrical protein localization. I became interested in this topic as a result of my work with the IcsA protein of Shigella flexneri. Shigella is an organism of extreme importance in the area of public health, causing an estimated 1.1 million deaths per annum, especially in countries where the level of hygiene and medical care are compromised. The asymmetric surface localization of IcsA is crucial in Shigella pathogenesis; bacteria that do not localize IcsA to the old pole do not efficiently spread from one epithelial cell to other uninfected cells. The recruitment of actin as mediated by the IcsA protein allows the bacteria to move in a directional fashion inside these cells and also provides a propulsive force that allows the bacteria to then invade and spread to other cells.
The Saccharomyces cerevisiae protein Rax2 has some particularly interesting parallels to IcsA. Rax2 plays a role in axial budding, and is asymmetrically localized to the pole of the yeast cell at the site where budding occurs. Rax2 interacts with actin cytoskeletal proteins and shares numerous short regions of homology with IcsA. I am using functional genomics techniques, including Synthetic Genetic Analysis (SGA), to define proteins that interact with Rax2 and thus are responsible for the asymmetric localization of this protein in yeast.