title: Small GTPases of the Ras superfamily regulate intestinal epithelial homeostasis and barrier function via common and unique mechanisms.
abstract: The intestinal epithelium forms a stable barrier protecting underlying tissues from pathogens in the gut lumen. This is achieved by specialized integral membrane structures such as tight and adherens junctions that connect neighboring cells and provide stabilizing links to the cytoskeleton. Junctions are constantly remodeled to respond to extracellular stimuli. Assembly and disassembly of junctions is regulated by interplay of actin remodeling, endocytotic recycling of junctional proteins, and various signaling pathways. Accumulating evidence implicate small G proteins of the Ras superfamily as important signaling molecules for the regulation of epithelial junctions. They function as molecular switches circling between an inactive GDP-bound and an active GTP-bound state. Once activated, they bind different effector molecules to control cellular processes required for correct junction assembly, maintenance and remodelling. Here, we review recent advances in understanding how GTPases of the Rho, Ras, Rab and Arf families contribute to intestinal epithelial homeostasis.
authors.affiliation: Department of Molecular Biomedicine; Center for Research and Advanced Studies of the National Polytechnic Institute (Cinvestav del IPN); Mexico City, Mexico.
authors.forename: Alí Francisco
authors.initials: AF
authors.lastname: Citalán-Madrid
authors.affiliation: Department of Molecular Biomedicine; Center for Research and Advanced Studies of the National Polytechnic Institute (Cinvestav del IPN); Mexico City, Mexico.
authors.forename: Alexander
authors.initials: A
authors.lastname: García-Ponce
authors.affiliation: Department of Molecular Biomedicine; Center for Research and Advanced Studies of the National Polytechnic Institute (Cinvestav del IPN); Mexico City, Mexico.
authors.forename: Hilda
authors.initials: H
authors.lastname: Vargas-Robles
authors.affiliation: Department of Infectomics and Molecular Pathogenesis; Center for Research and Advanced Studies of the National Polytechnic Institute (Cinvestav del IPN); Mexico City, Mexico.
authors.forename: Abigail
authors.initials: A
authors.lastname: Betanzos
authors.affiliation: Department of Molecular Biomedicine; Center for Research and Advanced Studies of the National Polytechnic Institute (Cinvestav del IPN); Mexico City, Mexico.
authors.forename: Michael
authors.initials: M
authors.lastname: Schnoor
keywords: Arf; Rac; Rap; Ras; Rho; actin cytoskeleton; adherens junction; cdc42; colitis; inflammatory bowel disease; tight junction