National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R01GM052586
米国
引用
ジャーナル: Science / 年: 2020 タイトル: Structural basis of ER-associated protein degradation mediated by the Hrd1 ubiquitin ligase complex. 著者: Xudong Wu / Marc Siggel / Sergey Ovchinnikov / Wei Mi / Vladimir Svetlov / Evgeny Nudler / Maofu Liao / Gerhard Hummer / Tom A Rapoport / 要旨: Misfolded luminal endoplasmic reticulum (ER) proteins undergo ER-associated degradation (ERAD-L): They are retrotranslocated into the cytosol, polyubiquitinated, and degraded by the proteasome. ERAD- ...Misfolded luminal endoplasmic reticulum (ER) proteins undergo ER-associated degradation (ERAD-L): They are retrotranslocated into the cytosol, polyubiquitinated, and degraded by the proteasome. ERAD-L is mediated by the Hrd1 complex (composed of Hrd1, Hrd3, Der1, Usa1, and Yos9), but the mechanism of retrotranslocation remains mysterious. Here, we report a structure of the active Hrd1 complex, as determined by cryo-electron microscopy analysis of two subcomplexes. Hrd3 and Yos9 jointly create a luminal binding site that recognizes glycosylated substrates. Hrd1 and the rhomboid-like Der1 protein form two "half-channels" with cytosolic and luminal cavities, respectively, and lateral gates facing one another in a thinned membrane region. These structures, along with crosslinking and molecular dynamics simulation results, suggest how a polypeptide loop of an ERAD-L substrate moves through the ER membrane.