Endosomes are important cellular compartments for sorting internalized cargo and immune sensing. In this issue, Wang et al describe a novel signaling pathway induced by endocytosed bacterial outer membrane vesicles, where sorting nexin 10 and caspase-5 act at the endosome to promote cytosolic exposure of LPS and initiate signaling to alter epithelial layer integrity. This study presents the first example of a specialized function for caspase-5, distinct from the inflammasome function executed by the closely related paralog caspase-4.
© 2021 The Authors.