ERM Proteins Play Distinct Roles in Cell Invasion by Extracellular Amastigotes of Trypanosoma cruzi

Abstract

The protozoan parasite Trypanosoma cruzi is the causative agent of Chagas' disease. In mammalian hosts, T. cruzi alternates between trypomastigote and amastigote forms. Additionally, trypomastigotes can differentiate into amastigotes in the extracellular environment generating infective extracellular amastigotes (EAs). Ezrin-radixin-moesin (ERM) are key proteins linking plasma membrane to actin filaments, the major host cell component responsible for EA internalization. Our results revealed that depletion of host ezrin and radixin but not moesin inhibited EAs invasion in HeLa cells. ERM are recruited and colocalize with F-actin at EA invasion sites as shown by confocal microscopy. Invasion assays performed with cells overexpressing ERM showed increased EAs invasion in ezrin and radixin but not moesin overexpressing cells. Finally, time-lapse experiments have shown altered actin dynamics leading to delayed EA internalization in ezrin and radixin depleted cells when compared to control or moesin depleted cells. Altogether, these findings show distinct roles of ERM during EAs invasion, possibly regulating F-actin dynamics and plasma membrane interplay.

ERM Proteins at the Crossroad of Leukocyte Polarization, Migration and Intercellular Adhesion

“…Ligand binding to phagocytic receptors activates phospholipase (PL)C/D to produce IP 3 , which can trigger an increase of intracellular Ca 2+ , inducing the translocation of µ-calpain from the cytosol to the emerging phagocytic cup where it is activated to cleave ezrin and break the linkage between the PM and the actin cortex (reviewed in [114]). The specific role of ezrin in the formation of the phagocytic cup is supported by a recent report showing that ezrin (but not moesin) promotes the formation of functional phagocytic cup-like invasive structures during infection of mammalian cells by extracellular amastigotes of Trypanosoma cruzi [115]. Detachment of ezrin from the PM may relax it but also release Rac-1-GEFs and thereby stimulate activation of Rac-1 and its effector WASP-family verprolin-homologous protein (WAVE), which can trigger localized actin polymerization by the Arp2/3 complex, pushing the PM away to form the phagocytic cup [116].…”

Aquaporin-3 mediates ovarian steroid hormone-induced motility of endometrial epithelial cells

“…Furthermore, neither ezrin nor AQP3 was detected in the corresponding IgG control precipitates. It has been reported that ezrin co-localizes with F-actin ( Ferreira et al , 2017 ). To elucidate the relationship between AQP3 and ezrin, we examined ezrin expression in RL95-2 cells treated with and without siRNA targeting AQP3 (Fig.…”

Amastigote Synapse: The Tricks of Trypanosoma cruzi Extracellular Amastigotes

“…In 2016 Ferreira et al (2016) described that TcMVK (yellow) is secreted by EAs promoting their invasion and the activation of diverse actin related host proteins (orange). Additionally, in 2017, we described that ezrin and radixin (cyan), but not moesin (light gray) are involved in actin regulation and EA invasion independent of their phosphorylation (light gray P) activation mechanism ( Ferreira et al, 2017 ). Recently, we observed the participation of Rho GTPases (Rac1 and Cdc42) and their effector proteins regulating actin polymerization signaling and promoting EA invasion, although RhoA inhibited these events (green) ( Bonfim-Melo et al, 2018 ).…”

“…Our group demonstrated that ERM proteins are recruited to parasite invasion sites and that depletion of ezrin and radixin inhibits EA invasion. Accordingly, ezrin and radixin overexpression enhances parasite invasion ( Ferreira et al, 2017 ). Despite structural and functional similarity to ezrin and radixin, curiously moesin does not seem to be involved in EA invasion because its depletion or overexpression did not significantly alter parasite invasion in HeLa cells ( Ferreira et al, 2017 ).…”

“…Despite structural and functional similarity to ezrin and radixin, curiously moesin does not seem to be involved in EA invasion because its depletion or overexpression did not significantly alter parasite invasion in HeLa cells ( Ferreira et al, 2017 ). Our findings also indicated that ERM participation in EA invasion does not depend on its classical threonine C-terminal phosphorylation because overexpression of phospho or dephosphomimetic mutants did not alter the EA uptake when compared to the wild-type isoforms ( Hao et al, 2009 ; Bosk et al, 2011 ; Ferreira et al, 2017 ). Consistent with this hypothesis, host cells in contact with EAs do not present increased ERM phosphorylation ( Ferreira et al, 2017 ).…”