SEL1L and cytomegalovirus infection: UL148 contributes to activation of the unfolded protein response (UPR) during HCMV infection (10) and copurifies from infected cells with SEL1L (8), an adaptor subunit for the E3 ubiquitin ligase HRD1, which plays crucial roles in ER-associated degradation (ERAD) of terminally misfolded glycoprotein substrates (15).