Component of the ERLIN1/ERLIN2 complex which mediates the endoplasmic reticulum-associated degradation (ERAD) of inositol 1,4,5-trisphosphate receptors (IP3Rs). Involved in regulation of cellular cholesterol homeostasis by regulation the SREBP signaling pathway. Binds cholesterol and may promote ER retention of the SCAP-SREBF complex (PubMed:24217618). (Microbial infection) Required early in hepatitis C virus (HCV) infection to initiate RNA replication, and later in the infection to support infectious virus production. Forms a heteromeric complex with ERLIN2 (PubMed:19240031). In complex with ERLIN2, interacts with RNF170 (PubMed:21610068). Interacts with AMFR and SYVN1 (PubMed:21343306). Associated with lipid raft-like domains of the endoplasmic reticulum membrane. Expressed in heart, placenta, liver, kidney, pancreas, prostate, testis, ovary and small intestine. The disease is caused by variants affecting the gene represented in this entry. Belongs to the band 7/mec-2 family. Truncated N-terminus. Truncated N-terminus. Truncated N-terminus.