Methods to study Rho GTPases using bacterial toxins

Abstract

Bacterial pathogens developed several strategies to overcome defense systems of eukaryotic hosts. Within the infection process they need to attach to and cross through epithelial layers, escape from the innate and adaptive immune response, and find a physiological niche to survive. For this purpose bacteria developed toxins that specifically target central eukaryotic proteins, for example actin or Rho GTPases as regulators of the actin cytoskeleton. Some bacterial toxins catalyze a covalent modification of Rho GTPases to keep these molecular switches in a constitutive active or inactive state. This leads to rearrangement of the actin cytoskeleton. Toxin-treated cells show typical morphological changes depending on substrate specificity and action of the toxins. In this chapter I describe methods to illustrate how bacterial toxins may help to study the involvement of Rho GTPases in physiological and pathophysiological processes.