Toxins Acting on Intracellular Targets: Only Foes or Also Friends?
Teresa Frisan, Riccardo Guidi and Lina Guerra
from: Bacterial Pathogenesis: Molecular and Cellular Mechanisms (Edited by: Camille Locht and Michel Simonet). Caister Academic Press, U.K. (2012)
Abstract
Bacteria possess an arsenal of virulence factors that allow them to colonize, invade and replicate within hostile niches, such as immunocompetent individuals. Bacterial toxins are among the most sophisticated virulence factors. They are highly specific for their target. Specificity is defined at the level of the target cell (presence of the receptor) and at the level of the substrate, since most of them are enzymes and require specific protein-protein interactions to exert their toxic activity. Some of them are also very powerful, and are among the most toxic compounds known to date. To gain access to their targets within the host cell, these molecules have exploited all the possible cellular routes of internalization: from direct translocation through the plasma membrane, to retrograde transport through the Golgi complex and the endoplasmic reticulum. Identification of their mode of action, their receptors and internalization routes has been instrumental to understand the role of toxins in the pathogenesis of bacteria-induced diseases, and has allowed production of prophylactic vaccines. Last but not least, bacterial toxins have been and are still used as tools in biomedical research to characterize basic cellular processes read more ...