Lysosomal membrane glycoprotein which plays a role in the unfolded protein response (UPR) that contributes to protein degradation and cell survival during proteasomal dysfunction. Plays a role in the process of fusion of the lysosome with the autophagosome, thereby modulating the autophagic process. Promotes hepatocellular lipogenesis through activation of the PI3K/Akt pathway. May also play a role in dendritic cell function and in adaptive immunity.; (Microbial infection) Plays a positive role in post-entry steps of influenza A virus replication, either virus uncoating, cytosolic transport, or nuclear import of viral components, and promotes nuclear accumulation of influenza nucleoprotein/NP at early stages of viral infection.; (Microbial infection) Supports the FURIN-mediated cleavage of mumps virus fusion protein F by interacting with both FURIN and the unprocessed form but not the processed form of the viral protein F.; (Microbial infection) Promotes the intracellular proliferation of Salmonella typhimuium.