Role of the proteasome in membrane extraction of a short-lived ER-transmembrane protein

摘要: Selective degradation of proteins at the endoplasmic reticulum (ER-associated degradation) is thought to proceed largely via cytosolic ubiquitin-proteasome pathway. Recent data have indicated that dislocation short-lived integral-membrane proteolytic system may require components Sec61 translocon. Here we show proteasome itself can participate in extraction an ER-membrane protein from lipid bilayer. In yeast mutants expressing functionally attenuated proteasomes, a doubly membrane-spanning proceeds rapidly through N-terminal domain substrate, but slows down considerably when continued molecule requires membrane extraction. Thus, proteasomes engaged ER directly process transmembrane mechanism which substrate and its proteolysis are coupled. We therefore propose retrograde transport substrates be driven activity proteasome.