In the endoplasmic reticulum (ER), the fidelity of protein synthesis is safeguarded by ER-associated protein degradation (ERAD). This pathway retrotranslocates aberrant polypeptides from the ER to the cytosol for degrada- tion by the proteasome [l]. In S. Cere- visiae, several membrane-embedded ubiquitin ligases are responsible for ubiquitination of retrotranslocated products: Hrd1 ubiquitinates substrates bearing misfolded domains in the lumen and membranes; Doa 10 aeals with substrate carrying amisfolded cytosolic domain [2,3]. Akey, yet poorly defined step in ERAD is the translocation of polypeptide across the membrane ostulated to be occur through conduit formed by ubiquitin ligases such as Hrdl [4]. In a recent issue of Cell, Baldridge and Rapoport demonstrate that Hrdl is indeed a protein retrotranslocation channel [5].