Vesicular Trafficking in Entamoeba histolytica is Essential for its Virulence

Abstract

Vesicular trafficking is based on membrane remodelling that produces vesicles with distinct composition. This allows the transport of nutrients and molecules, and the communication among intracellular organelles.Vesicular trafficking is one of themainmechanisms for pathogens virulence. Besides, multiple factors elicit parasite resistance to host defences, changing the environment during tissue invasion. Virulence factors are linked to the secretory (exocytosis) and importing (endocytosis) pathways. In this paper, we discuss the relevance of vesicular trafficking in the virulence of the protozoan Entamoeba histolytica. An efficient function of virulence factors during adherence to and phagocytosis of target cells and tissue invasion by trophozoites, requires the transport of specific molecules. The EhGal/GalNAc lectin, the EhCPADH complex, phosphoinositides, KERP1, EhRabs, EhCPs, LBPA and cholesterol are some of the molecules involved in the uptake, movement and digestion of the prey.Moreover, phagocytosis is an event that depends on activemembranes fusion and fission, finely controlled by rearrangements of the actin cytoskeleton. During this process, a diversity of signalling transducers and effector molecules are implicated in endosomes and phagosomes formation and maturation, including the ESCRT machinery. Furthermore, some of these molecules participate in the exocytosis and others are secreted by the parasite and reach the target cell to initiate the invasion. For instance, proteins forming the EhCPADH complex, involved in adherence and phagocytosis, are secreted. EhCP112 and EhADH reach target cells and penetrate them by caveolae or clathrin-coated vesicles. These proteins destroy the intercellular junctions and provoke cell detachment and the impairment of epithelium homeostasis, eventually resulting in symptomatic manifestations of amoebiasis. In summary, vesicular trafficking results determinant for the transport of virulence factors during the whole E. histolytica pathogenesis process.