Plays a role in the endoplasmic reticulum quality control (ERQC) system also called ER-associated degradation (ERAD) involved in ubiquitin-dependent degradation of misfolded endoplasmic reticulum proteins. Enhances SYVN1 stability. Plays a role in LPL maturation and secretion. Required for normal differentiation of the pancreas epithelium, and for normal exocrine function and survival of pancreatic cells. May play a role in Notch signaling. Homodimer and homooligomer (By similarity). May form a complex with ERLEC1, HSPA5, OS9, and SYVN1 (By similarity). Interacts with FOXRED2 and EDEM1 (By similarity). Interacts with LPL and LMF1; may stabilize the complex formed by LPL and LMF1 and thereby promote the export of LPL dimers (By similarity). Component of the HRD1 complex, which comprises at least SYNV1/HRD1, DERL1/2, FAM8A1, HERPUD1/HERP, OS9, SEL1L and UBE2J1 (By similarity). SYNV1 assembles with SEL1L and FAM8A1 through its transmembrane domains, but interaction with its cytoplasmic domain is required to confer stability to FAM8A1 and enhance recruitment of HERPUD1 (By similarity). The interaction with SYNV1/HRD1 is direct (By similarity). N-glycosylated. Belongs to the sel-1 family.