REQUIREMENT OF CDC42 FOR SALMONELLA-INDUCED CYTOSKELETAL AND NUCLEAR RESPONSES

The bacterial pathogen Salmonella typhimurium triggers host cell signa ling pathways that lead to cytoskeletal and nuclear responses required for pathogenesis. Here, the role of the small guanosine triphosphate (GTP)-binding protein CDC42Hs in these responses was examined. Express ion of a dominant interfering mutant of CDG42 (CDC42HsN17) prevented S . typhimurium-induced cytoskeletal reorganization and subsequent macro pinocytosis and bacterial internalization into host cells. Cells expre ssing constitutively active CDC42 (CDC42HsV12) internalized an S. typh imurium mutant unable to trigger host cell responses. Furthermore, exp ression of CDC42HsN17 prevented S. typhimurium-induced JNK kinase acti vation. These results indicate that CDC42 is required for bacterial in vasion and induction of nuclear responses in host cells.