New insights into the role of the cytoskeleton in phagocytosis of Entamoeba histolytica

Abstract

Entamoeba histolytica, a human parasite, crosses the natural barriers of the intestine and, in turn, spreads into the deeper organs, resulting in amoebiasis. The motility of the parasite and its ability to lyse or phagocytose human cells facilitates passage of the amoeba through the intestinal epithelium. Little is known about the uptake of material by this parasite; nevertheless, the cytoskeleton is believed to play a role in phagocytosis. Myosin IB, an actin‐binding protein, localizes to the phagocytic cup and, with time, surrounds the internalized phagosome itself. The role of unconventional myosins in phagocytosis has also been demonstrated in other cell types, suggesting that this molecular mechanism is a common denominator in phagocytic events. Here, we summarize the emerging view of the role of unconventional myosins as well as other cytoskeleton‐associated proteins in pseudopod formation at early stages of phagocytosis and during the late step of this process in E. histolytica.

Functions of myosin motors tailored for parasitism

“…The amoeba E. histolytica is a human pathogen that possesses only a myosin II and an unconventional myosin IB that exhibits the same domain architecture as other class I myosins ( Figure 1) [7,8]. EhMyoIB is an intriguing motor also able to cross-link actin filaments [9].…”

Downregulation of an Entamoeba histolytica Rhomboid Protease Reveals Roles in Regulating Parasite Adhesion and Phagocytosis

“…Parasite motility is a key virulence factor, as it is required for multiple steps of the invasion process (27,57). Parasites must maneuver across the colonic epithelium, penetrate the destroyed epithelial barrier, and travel to extraintestinal sites of infection.…”

The genome of the protist parasite Entamoeba histolytica

“…Rab and Arf protein family expansions reflect the increased complexity and number of vesicle fusion and recycling steps that have been associated with phagocytosis and pinocytosis in amoebae 15 . The cytoskeleton has a number of important roles in parasite motility, contact-dependant killing and phagocytosis of host intestinal epithelial cells 16 . This is reflected in expansions of Rho GTPases and their regulators RhoGAPs and RhoGEFs, which control a number of processes involving the actin cytoskeleton.…”