INVOLVEMENT OF THE ACTIN CYTOSKELETON AND P21(RHO)-FAMILY GTPASES IN THE PATHOGENESIS OF THE HUMAN PROTOZOAN PARASITE ENTAMOEBA-HISTOLYTICA

It has been estimated that infection with the enteric protozoan parasi te Entamoeba histolytica kills more than 50,000 people a year. Central to the pathogenesis of this organism is its ability to directly lyse host cells and cause tissue destruction. Amebic lesions show evidence of cell lysis, tissue necrosis, and damage to the extracellular matrix . The specific molecular mechanisms by which these events are initiate d, transmitted, and effected are just beginning to be uncovered. In th is article we review what is known about host cell adherence and conta ct-dependent cytolysis. We cover the involvement of the actin cytoskel eton and small CTP-binding proteins of the p21(rho)-family in the proc ess of cell killing and phagocytosis, and also look at how amebic inte ractions with molecules of the extracellular matrix contribute to its cytopathic effects.