The function of WDR83OS (WD repeat domain 83 opposite strand, ENSG00000105583) is as follows. Component of the multi-pass translocon (MPT) complex that mediates insertion of multi-pass membrane proteins into the lipid bilayer of membranes (PubMed:12475939, PubMed:32814900, PubMed:36261522). The MPT complex takes over after the SEC61 complex: following membrane insertion of the first few transmembrane segments of proteins by the SEC61 complex, the MPT complex occludes the lateral gate of the SEC61 complex to promote insertion of subsequent transmembrane regions (PubMed:32814900, PubMed:36261522). Within the MPT complex, the PAT subcomplex sequesters any highly polar regions in the transmembrane domains away from the non-polar membrane environment until they can be buried in the interior of the fully assembled protein (By similarity). Within the PAT subcomplex, WDR83OS/Asterix binds to and redirects the substrate to a location behind the SEC61 complex (By similarity). {ECO:0000250|UniProtKB:A0A8I3NQW8, ECO:0000269|PubMed:12475939, ECO:0000269|PubMed:32814900, ECO:0000269|PubMed:36261522}.