The ER-phagy receptor FAM134B is targeted bySalmonellaTyphimurium to promote infection

Abstract

ABSTRACTMacroautophagy/autophagy is a key catabolic-recycling pathway that can selectively target damaged organelles or invading pathogens for degradation. The selective autophagic degradation of the endoplasmic reticulum (hereafter referred to as ER-phagy) is a homeostatic mechanism, controlling ER size, the removal of misfolded protein aggregates, and organelle damage. ER-phagy is also stimulated by pathogen infection. However, the link between ER-phagy and bacterial infection remains poorly understood, as are the mechanisms evolved by pathogens to escape the effects of ER-phagy. Here, we show thatSalmonella entericaserovar Typhimurium inhibits ER-phagy by targeting the ER-phagy receptor FAM134B, leading to a pronounced increase inSalmonellaviability after invasion.Salmonellaprevents FAM134B oligomerization, which is required for efficient ER-phagy. FAM134B knock-out raises intracellularSalmonellanumber, while FAM134B activation reducesSalmonellaburden. Additionally, we found thatSalmonellatargets FAM134B through the bacterial effector SopF to enhance intracellular survival through ER-phagy inhibition. Furthermore, FAM134B knock-out mice infected withSalmonellapresented severe intestinal damage and increased bacterial burden. These results provide new mechanistic insight into the interplay between ER-phagy and bacterial infection, highlighting a key role for FAM134B in innate immunity.