Poisons, ruffles and rockets: Bacterial pathogens and the host cell cytoskeleton

The cytoskeleton of eukaryotic cells is affected by a number of bacterial a nd viral pathogens. In this review we consider three recurring themes of cy toskeletal involvement in bacterial pathogenesis: 1) the effect of bacteria l toxins on actin-regulating small GTP-binding proteins; 2) the invasion of non-phagocytic cells by the bacterial induction of ruffles at the plasma m embrane; 3) the formation of actin tails and pedestals by intracellular and extracellular bacteria, respectively. Considerable progress has been made recently in the characterization of these processes. It is becoming clear t hat bacterial pathogens have developed a variety of sophisticated mechanism s for utilizing the complex cytoskeletal system of host cells. These bacter ially-induced processes are now providing unique insights into the regulati on of fundamental eukaryotic mechanisms.