title: Heterotrimeric G-protein signaling is critical to pathogenic processes in Entamoeba histolytica.
abstract: Heterotrimeric G-protein signaling pathways are vital components of physiology, and many are amenable to pharmacologic manipulation. Here, we identify functional heterotrimeric G-protein subunits in Entamoeba histolytica, the causative agent of amoebic colitis. The E. histolytica Gα subunit EhGα1 exhibits conventional nucleotide cycling properties and is seen to interact with EhGβγ dimers and a candidate effector, EhRGS-RhoGEF, in typical, nucleotide-state-selective fashions. In contrast, a crystal structure of EhGα1 highlights unique features and classification outside of conventional mammalian Gα subfamilies. E. histolytica trophozoites overexpressing wildtype EhGα1 in an inducible manner exhibit an enhanced ability to kill host cells that may be wholly or partially due to enhanced host cell attachment. EhGα1-overexpressing trophozoites also display enhanced transmigration across a Matrigel barrier, an effect that may result from altered baseline migration. Inducible expression of a dominant negative EhGα1 variant engenders the converse phenotypes. Transcriptomic studies reveal that modulation of pathogenesis-related trophozoite behaviors by perturbed heterotrimeric G-protein expression includes transcriptional regulation of virulence factors and altered trafficking of cysteine proteases. Collectively, our studies suggest that E. histolytica possesses a divergent heterotrimeric G-protein signaling axis that modulates key aspects of cellular processes related to the pathogenesis of this infectious organism.
authors.affiliation: Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America.
authors.forename: Dustin E
authors.initials: DE
authors.lastname: Bosch
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Kimple
authors.forename: Robin E
authors.initials: RE
authors.lastname: Muller
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Giguère
authors.forename: Mischa
authors.initials: M
authors.lastname: Machius
authors.forename: Francis S
authors.initials: FS
authors.lastname: Willard
authors.forename: Brenda R S
authors.initials: BR
authors.lastname: Temple
authors.forename: David P
authors.initials: DP
authors.lastname: Siderovski
mesh_terms: D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D018360:Crystallography, X-Ray; D004748:Entamoeba histolytica / Q000201:enzymology / Q000235:genetics / Q000276:immunology*; D004749:Entamoebiasis / Q000201:enzymology / Q000235:genetics / Q000276:immunology*; D044385:GTP-Binding Protein alpha Subunits / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D005786:Gene Expression Regulation / Q000276:immunology; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D006801:Humans; D019169:Jurkat Cells; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D064067:Rho Guanine Nucleotide Exchange Factors; D014158:Transcription, Genetic / Q000276:immunology; D037521:Virulence Factors / Q000096:biosynthesis / Q000737:chemistry / Q000276:immunology*
chemical_list: D044385:GTP-Binding Protein alpha Subunits; D020662:Guanine Nucleotide Exchange Factors; D015800:Protozoan Proteins; D064067:Rho Guanine Nucleotide Exchange Factors; D037521:Virulence Factors