Molecular mechanism for the commitment of TOM1 to cargo trafficking

Abstract

TOM1 is an adaptor protein that functions in protein trafficking by recognition of ubiquitinated receptors (cargo) via its VHS and GAT domains. At physiological conditions, TOM1 performs its trafficking functions at the surface of early endosomes where it sorts cargo for their lysosomal degradation. Interestingly, during the infection stage of the bacterium Shigella flexneri, TOM1 is sequestered to signaling endosomes by binding to phosphatidylinositol 5-phosphate (PtdIns5P), causing a delay in endosome maturation, effectively shutting down the degradative pathway with a concomitant increase in signaling for host cell survival.