ERAD Tuning of the HRD1 Complex Component AtOS9 Is Modulated by an ER-Bound E2, UBC32

When membrane proteins and secretory proteins are incompletely folded or mis-folded, they are retained in the endoplasmic reticulum (ER) for further folding or degradation. Two major degradation systems involved in removing the mis-folded or unfolded proteins retained in the ER have been identified: ER-associated degradation (ERAD), which targets misfolded proteins for ubiquitination and subsequent degradattion through the proteasome pathway (McCracken and Brodsky, 1996), and ER quality control (ERQC) autophagy, which removes aggregated proteins that cannot be retrotranslocated to the cytoplasmic proteasome (Houck et al., 2014).