May be involved in the degradation process of specific misfolded endoplasmic reticulum (ER) luminal proteins. May also 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. Belongs to the derlin family.