EMC complex / protein insertion into ER membrane by stop-transfer membrane-anchor sequence / protein folding in endoplasmic reticulum / phospholipid transport / autophagosome assembly / phospholipid metabolic process / endoplasmic reticulum to Golgi vesicle-mediated transport / protein transport / protein-folding chaperone binding / endoplasmic reticulum membrane ...EMC complex / protein insertion into ER membrane by stop-transfer membrane-anchor sequence / protein folding in endoplasmic reticulum / phospholipid transport / autophagosome assembly / phospholipid metabolic process / endoplasmic reticulum to Golgi vesicle-mediated transport / protein transport / protein-folding chaperone binding / endoplasmic reticulum membrane / endoplasmic reticulum / membrane / nucleus 類似検索 - 分子機能
Protein Sop4 / Suppressor of PMA 1-7 protein / TMEM85/ER membrane protein complex subunit 4 / Protein of unknown function (DUF1077) / ER membrane protein complex subunit 6 / ER membrane protein complex subunit 3 / ER membrane protein complex subunit 1, C-terminal / Membrane magnesium transporter / ER membrane protein complex subunit 1 / ER membrane protein complex subunit 6-like ...Protein Sop4 / Suppressor of PMA 1-7 protein / TMEM85/ER membrane protein complex subunit 4 / Protein of unknown function (DUF1077) / ER membrane protein complex subunit 6 / ER membrane protein complex subunit 3 / ER membrane protein complex subunit 1, C-terminal / Membrane magnesium transporter / ER membrane protein complex subunit 1 / ER membrane protein complex subunit 6-like / EMC6 / ER membrane protein complex subunit 1, C-terminal / Membrane magnesium transporter / ER membrane protein complex subunit 10 / ER membrane protein complex subunit 2-like / Integral membrane protein EMC3/TMCO1-like / Integral membrane protein EMC3/TMCO1-like / Integral membrane protein DUF106 / TPR repeat profile. / Tetratricopeptide repeat / Tetratricopeptide-like helical domain superfamily 類似検索 - ドメイン・相同性
ER membrane protein complex subunit 1 / ER membrane protein complex subunit 3 / Protein SOP4 / ER membrane protein complex subunit 5 / ER membrane protein complex subunit 2 / ER membrane protein complex subunit 4 / Endoplasmic reticulum membrane protein complex subunit 10 / ER membrane protein complex subunit 6 類似検索 - 構成要素
National Institutes of Health/National Cancer Institute (NIH/NCI)
R01-CA231466
米国
引用
ジャーナル: Nature / 年: 2020 タイトル: Structure of the ER membrane complex, a transmembrane-domain insertase. 著者: Lin Bai / Qinglong You / Xiang Feng / Amanda Kovach / Huilin Li / 要旨: The endoplasmic reticulum (ER) membrane complex (EMC) cooperates with the Sec61 translocon to co-translationally insert a transmembrane helix (TMH) of many multi-pass integral membrane proteins into ...The endoplasmic reticulum (ER) membrane complex (EMC) cooperates with the Sec61 translocon to co-translationally insert a transmembrane helix (TMH) of many multi-pass integral membrane proteins into the ER membrane, and it is also responsible for inserting the TMH of some tail-anchored proteins. How EMC accomplishes this feat has been unclear. Here we report the first, to our knowledge, cryo-electron microscopy structure of the eukaryotic EMC. We found that the Saccharomyces cerevisiae EMC contains eight subunits (Emc1-6, Emc7 and Emc10), has a large lumenal region and a smaller cytosolic region, and has a transmembrane region formed by Emc4, Emc5 and Emc6 plus the transmembrane domains of Emc1 and Emc3. We identified a five-TMH fold centred around Emc3 that resembles the prokaryotic YidC insertase and that delineates a largely hydrophilic client protein pocket. The transmembrane domain of Emc4 tilts away from the main transmembrane region of EMC and is partially mobile. Mutational studies demonstrated that the flexibility of Emc4 and the hydrophilicity of the client pocket are required for EMC function. The EMC structure reveals notable evolutionary conservation with the prokaryotic insertases, suggests that eukaryotic TMH insertion involves a similar mechanism, and provides a framework for detailed understanding of membrane insertion for numerous eukaryotic integral membrane proteins and tail-anchored proteins.