May be required for the degradation process of some specific misfolded endoplasmic reticulum (ER) luminal proteins. Participates in the transfer of misfolded proteins from the ER to the cytosol, where they are destroyed by the proteasome in a ubiquitin-dependent manner. Its precise function remains unclear, but its ability to complement der1 mutations in C.cerevisiae, suggests a similar function in the degradation of ER misfolded proteins. By endoplasmic reticulum stress. Belongs to the derlin family.