Investigating the function of Rho family GTPases during Salmonella/host cell interactions.

Salmonella enterica comprise a family of pathogenic gram-negative bacteria that have evolved sophisticated virulence mechanisms to enter non-phagocytic cells. The entry event is the result of a carefully orchestrated modulation of Rho family GTPase activity within the host cell, which in turn triggers localized remodeling of the actin cytoskeleton. These cytoskeletal rearrangements drive profuse membrane ruffling and lamellipodial extensions that envelop bacteria and trigger their internalization. This chapter describes a number of methods used to investigate the role of Rho family GTPases during Salmonella/host cell interactions. In particular, we detail a variety of complementary techniques, including affinity pull-down assays and bacterial-induced membrane ruffling and internalization assays to show that Salmonella-induced actin remodeling and entry require the Rho family members Rac and RhoG.