Pseudomonas aeruginosa (PA) is an opportunistic gram-negative pathogen responsible for a large number of nosocomial infections. Dr. Joanne Engel and her group have shown that PA103 induces apoptotic-like cell death in epithelial cells and macrophages by a Type III Secretion System (TTSS)-dependent mechanism. Consistent with the results of others, They have found this to be a Fas ligand- and Fas receptor-dependent process. We propose that PA-induced apoptosis occurs either by (A) direct translocation of a bacterial effector into the host cell (PAF, for Pseudomonas Apoptosis Factor) by the TTSS, resulting in activation of Fas-dependent apoptosis or by (B) direct induction of Fas-dependent apoptosis by one or more components of the type III translocation apparatus itself. We will identify the mechanism by which PAl03 induces TTS-dependent apoptotic-like cell death in eukaryotic cells. We will initially use genetic and proteomic approaches to identify a putative apoptosis-inducing type III secreted effector molecule. We may also test the alternative hypothesis that the TTSS itself is responsible for the induction of apoptosis by PA. We will express the PA TTSS in a Yersinia strain that lacks the plasmid encoded TTSS and test for restoration of apoptosis-inducing activity.
| Wood, Stephen; Sivaramakrishnan, Gayathri; Engel, Joanne et al. (2011) Cell migration regulates the kinetics of cytokinesis. Cell Cycle 10:648-54 |
| Shafikhani, Sasha H; Mostov, Keith; Engel, Joanne (2008) Focal adhesion components are essential for mammalian cell cytokinesis. Cell Cycle 7:2868-76 |
| Shafikhani, Sasha H; Morales, Christina; Engel, Joanne (2008) The Pseudomonas aeruginosa type III secreted toxin ExoT is necessary and sufficient to induce apoptosis in epithelial cells. Cell Microbiol 10:994-1007 |
| Brandt, Sabine; Shafikhani, Sasha; Balachandran, Priya et al. (2007) Use of a novel coinfection system reveals a role for Rac1, H-Ras, and CrkII phosphorylation in Helicobacter pylori-induced host cell actin cytoskeletal rearrangements. FEMS Immunol Med Microbiol 50:190-205 |
| Shafikhani, Sasha H; Engel, Joanne (2006) Pseudomonas aeruginosa type III-secreted toxin ExoT inhibits host-cell division by targeting cytokinesis at multiple steps. Proc Natl Acad Sci U S A 103:15605-10 |
