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.