DERL1 (Derlin-1) is specifically required for the degradation process of misfolded endoplasmic reticulum (ER) luminal proteins. DERL1 (Derlin-1) aarticipates in the transfer of misfolded proteins from the ER to the cytosol, where they are destroyed by the proteasome in a ubiquitin-dependent manner. DERL1 may act by forming a channel that allows the retro-translocation of misfolded proteins into the cytosol and transfer them to the ATPase VCP complex, which translocates and ubiquitinates misfolded proteins. In case of infection by the cytomegalovirus, it plays a central role in the export from the ER and subsequent degredation of MHC class I heavy chains via its interaction with US11 viral protein, which recognizes and associates with MHC class I heavy chains. Also participates in the degradation process of misfolded cytomegalovirus US2 protein. DERL1 (Derlin-1) interacts with VIMP/SELS and indirectly with VCP, suggesting that it forms a membrane complex with VIMP that serves as a receptor for VCP.