ARHGEF2 isoform switching couples intestinal epithelial barrier function with autophagic host defense response to pathogens

Abstract Intestinal epithelial integrity is essential for host defense, yet how epithelial junctional scaffolds coordinate antimicrobial immunity remains unclear. We show that the long GEF-H1 isoforms (mouse Arhgef2-207; human ARHGEF2-219) localize to adherens junctions in polarized epithelial cells through interactions with actin and Nectin-3, whereas the shorter Arhgef2-201 isoform localizes to tight junctions. Conditional deletion of epithelial Arhgef2-207 induces Arhgef2-201 expression, disrupts barrier integrity, activates autophagy, and causes small-intestinal inflammation. In human intestinal organoids, Listeria monocytogenes selectively depletes junction-associated ARHGEF2-219, triggering a switch to ARHGEF2-201 and RhoA- and STING-mediated autophagic signaling. This transition coincides with loss of the Na⁺/K⁺-ATPase and epithelial polarity. Here we show that a pathogen-induced ARHGEF2 isoform switch links junctional perturbation to autophagic responses and immune activation, revealing a mechanism that couples barrier disruption to cell-intrinsic antimicrobial defense.