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Structural Determinants of RGS‐RhoGEF Signaling Critical to Entamoeba histolytica Pathogenesis
Author(s) -
Bosch Dustin E,
Kimple Adam J,
Manning Alyssa J,
Muller Robin E,
Willard Francis S,
Machius Mischa,
Rogers Stephen L,
Siderovski David P
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.656.2
Subject(s) - heterotrimeric g protein , gtpase activating protein , biology , microbiology and biotechnology , protein subunit , prenylation , g protein , entamoeba histolytica , gtpase , signal transduction , biochemistry , genetics , gene , enzyme
G‐protein signaling pathways, as key components of physiologic responsiveness and timing, are frequent targets for pharmacologic intervention. Here, we identify an effector for heterotrimeric G‐protein a subunit (EhGα1) signaling from Entamoeba histolytica , the causative agent of amoebic colitis. EhGα1 interacts with this effector and GTPase‐accelerating protein (GAP), EhRGS‐RhoGEF, in a nucleotide state‐selective fashion. Co‐expression of EhRGS‐RhoGEF with constitutively active EhGα1 and EhRacC leads to Rac‐dependent spreading in Drosophila S2 cells. EhRGS‐RhoGEF overexpression in E. histolytica trophozoites leads to reduced migration toward serum and lower cysteine protease activity, as well as reduced attachment to, and killing of, host cells. A 2.3 Å crystal structure of the full‐length EhRGS‐RhoGEF reveals a putative inhibitory helix engaging the DH domain Rho‐binding surface and the PH domain. Mutational analysis of the EhGα1/EhRGS‐RhoGEF interface confirms a canonical RGS domain rather than a RhoGEF‐RGS (“rgRGS”) domain , suggesting a convergent evolution toward heterotrimeric and small G‐protein cross‐talk.