TY - JOUR T1 - Heterotrimeric G-protein Signaling Is Critical to Pathogenic Processes in Entamoeba histolytica A1 - Bosch, Dustin E. A1 - Kimple, Adam J. A1 - Muller, Robin E. A1 - Giguère, Patrick M. A1 - Machius, Mischa A1 - Willard, Francis S. A1 - Temple, Brenda R. S. A1 - Siderovski, David P. Y1 - 2012/11/15 N2 - Author Summary Entamoeba histolytica causes an estimated 50 million intestinal infections and 100,000 deaths per year worldwide. Here, we identify functional heterotrimeric G-protein subunits in Entamoeba histolytica, constituting a signaling pathway which, when perturbed, is seen to regulate multiple cellular processes required for pathogenesis. Like mammalian counterparts, EhGα1 forms a heterotrimer with EhGβγ that is dependent on guanine nucleotide exchange and hydrolysis. Despite engaging a classical G-protein effector, EhRGS-RhoGEF, EhGα1 diverges from mammalian Gα subunits and cannot be classified within mammalian Gα subfamilies, as highlighted by distinct structural features in our crystal structure of EhGα1 in the inactive conformation. To identify roles of G-protein signaling in pathogenesis-related cellular processes, we engineered trophozoites for inducible expression of EhGα1 or a dominant negative mutant, finding that G-protein signaling perturbation affects host cell attachment and the related process of contact-dependent killing, as well as trophozoite migration and Matrigel transmigration. A transcriptomic comparison of our engineered strains revealed differential expression of known virulence-associated genes, including amoebapores and cytotoxic cysteine proteases. The expression data suggested, and biochemical experiments confirmed, that cysteine protease secretion is altered upon G-protein overexpression, identifying a mechanism by which pathogenesis-related trophozoite behaviors are perturbed. In summary, E. histolytica encodes a vital heterotrimeric G-protein signaling pathway that is likely amenable to pharmacologic manipulation. JF - PLOS Pathogens JA - PLOS Pathogens VL - 8 IS - 11 UR - https://doi.org/10.1371/journal.ppat.1003040 SP - e1003040 EP - PB - Public Library of Science M3 - doi:10.1371/journal.ppat.1003040 ER -