Component of the endoplasmic reticulum quality control (ERQC) system also called ER-associated degradation (ERAD) involved in ubiquitin-dependent degradation of misfolded endoplasmic reticulum proteins. Binds to ubiquilins and this interaction is required for efficient degradation of CD3D via the ERAD pathway. Interacts with PSEN1 and PSEN2 (By similarity). Interacts with UBXN6 (By similarity). Interacts with UBQLN1, UBQLN2 and UBQLN4 (By similarity). Component of the HRD1 complex, which comprises at least SYNV1/HRD1, FAM8A1, HERPUD1/HERP, OS9, SEL1L and UBE2J1. FAM8A1 binding to SYNV1 may promote recruitment of HERPUD1 to the HRD1 complex (By similarity).