Plays an important role in endoplasmic reticulum-associated degradation (ERAD) that mediates ubiquitin-dependent degradation of misfolded endoplasmic reticulum proteins (PubMed:18711132, PubMed:24215460). By controlling the steady-state expression of the IGF1R receptor, indirectly regulates the insulin-like growth factor receptor signaling pathway (PubMed:26692333). Involved in inhibition of lipid droplet degradation by binding to phospholipase PNPL2 and inhibiting its activity by promoting dissociation of PNPL2 from its endogenous activator, ABHD5 which inhibits the rate of triacylglycerol hydrolysis (PubMed:23297223). Identified in a complex that contains SEL1L, OS9, FAF2/UBXD8, UBE2J1/UBC6E and AUP1 (PubMed:18711132). Interacts with YOD1 (PubMed:19818707). Interacts (via N-terminus) with UBQLN2 (via C-terminus) (PubMed:24215460). Interacts with PNPLA2 and UBAC2 (PubMed:23297223). Interacts with ZFAND2B; probably through VCP (PubMed:24160817). Interacts with LMBR1L (PubMed:31073040). Broadly expressed, with highest levels in brain. Up-regulated in T-cells and eosinophils from patients with atopic dermatitis.