Functional component of endoplasmic reticulum-associated degradation (ERAD) for misfolded lumenal glycoproteins, but not that of misfolded nonglycoproteins. May act by forming a channel that allows the retrotranslocation of misfolded glycoproteins into the cytosol where they are ubiquitinated and degraded by the proteasome. May mediate the interaction between VCP and the misfolded glycoproteins. May be involved in endoplasmic reticulum stress-induced pre-emptive quality control, a mechanism that selectively attenuates the translocation of newly synthesized proteins into the endoplasmic reticulum and reroutes them to the cytosol for proteasomal degradation. Forms homo- and heterooligomers with DERL2 and, to a lesser extent, with DERL1 (By similarity). Interacts with VCP and EDEM1 (By similarity). Interacts with SELENOK and SELENOS (PubMed:22016385). Interacts with the signal recognition particle/SRP and the SRP receptor; in the process of endoplasmic reticulum stress-induced pre-emptive quality control (By similarity). Highly expressed in spleen, lung, liver, spleen and testis. Expressed at intermediate level in kidney. Weakly or not expressed in brain, heart and skeletal muscle. Expressed in neural cells during enbryogenesis. From 11.5 dpc until 14.5 dpc, it is mainly expressed in the forebrain. From 15.5 dpc until birth, expression in the forebrain becomes weaker but is still observed in the olfactory bulb and the skin around the eyes, nose, limbs and tail, showing that its pattern of expression changes from the central nervous system to the peripheral tissues during development. Belongs to the derlin family.