Structural basis for membrane insertion by the human ER membrane protein complex

Pleiner, Tino; Tomaleri, Giovani Pinton; Januszyk, Kurt; Inglis, Alison J.; Hazu, Masami; Voorhees, R.M.

doi:10.1126/science.abb5008

Cited by 151 publications

(301 citation statements)

References 63 publications

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“…Subsequently, these 49 mutations were mapped onto the structure grouped by reporter phenotype ( Video 1 , Supplement File 2 ). To allow for direct comparison of our structure-guided mutant phenotypes with those published recently by others ( Pleiner et al, 2020 ; Bai et al, 2020 ; O'Donnell et al, 2020 ), we summarized all mutant data ( Supplementary file 3 ). A subset of the mutant cell lines was validated by genotyping ( Figure 1—figure supplement 9 ).…”

Section: Resultsmentioning

confidence: 99%

“…One EMC subunit (EMC3) shares limited sequence homology with a family of insertases that are evolutionarily related to the bacterial insertase YidC ( Samuelson et al, 2000 ; Kumazaki et al, 2014 ; Borowska et al, 2015 ; Anghel et al, 2017 ), perhaps explaining the insertase function of the complex. During the preparation of our manuscript, studies describing the structures of the yeast Get1/Get2/Get3 structures, human WRB/CAML/TRC40 ( McDowell et al, 2020 ), translocon bound to Nicalin-TMEM147-NOMO ( McGilvray et al, 2020 ), human structures of the EMC ( O'Donnell et al, 2020 ; Pleiner et al, 2020 ), and the yeast structure of the EMC ( Bai et al, 2020 ) were published. Those studies focused on the insertase activities of these proteins from the individual species; however, the elaboration of the EMC compared to other known membrane protein biogenesis factors and a diverse client range points to additional functionality that has so far eluded mechanistic explanation.…”

Section: Introductionmentioning

confidence: 99%

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Structural and mechanistic basis of the EMC-dependent biogenesis of distinct transmembrane clients

Miller-Vedam

Bräuning

Popova

et al. 2020

eLife

111

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Membrane protein biogenesis in the endoplasmic reticulum (ER) is complex and failure-prone. The ER membrane protein complex (EMC), comprising eight conserved subunits, has emerged as a central player in this process. Yet, we have limited understanding of how EMC enables insertion and integrity of diverse clients, from tail-anchored to polytopic transmembrane proteins. Here, yeast and human EMC cryo-EM structures reveal conserved intricate assemblies and human-specific features associated with pathologies. Structure-based functional studies distinguish between two separable EMC activities, as an insertase regulating tail-anchored protein levels and a broader role in polytopic membrane protein biogenesis. These depend on mechanistically coupled yet spatially distinct regions including two lipid-accessible membrane cavities which confer client-specific regulation, and a non-insertase EMC function mediated by the EMC lumenal domain. Our studies illuminate the structural and mechanistic basis of EMC's multifunctionality and point to its role in differentially regulating the biogenesis of distinct client protein classes.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Structural and mechanistic basis of the EMC-dependent biogenesis of distinct transmembrane clients

Miller-Vedam

Bräuning

Popova

et al. 2020

eLife

111

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“…(D) In yeast, the analogous WNK1/EMC8 interface on EMC2 is occupied by the N-terminus of EMC4. A structural overlay of yeast EMC2 (gray: PDB 6WB9) and human EMC2 (green: PDB 6WW7) is shown with or without human EMC8 (blue) and yeast EMC4 N-terminus (pink) (Bai et al, 2020;Pleiner et al, 2020). The N-terminus of EMC4 is poorly conserved, consistent with its non-essential role in binding EMC2 in metazoans.…”

Section: :mentioning

confidence: 98%

“…Overview of the cytosolic domain of the human EMC, assembled around EMC2 (PDB 6WW7;Pleiner et al, 2020). Inset: close-up on the cytosolic domain as viewed from the membrane.…”

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confidence: 99%

Regulated assembly of the ER membrane protein complex

Pleiner

Januszyk

Tomaleri

et al. 2020

Preprint

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SummaryThe assembly of nascent proteins into multi-subunit complexes is tightly regulated to maintain cellular homeostasis. The ER membrane protein complex (EMC) is an essential insertase that requires seven membrane-spanning and two soluble subunits for function. Here we show that the kinase With no lysine 1 (WNK1), known for its role in hypertension and neuropathy, is required for assembly of the human EMC. WNK1 uses a conserved amphipathic helix to stabilize the soluble subunit, EMC2, by binding to the EMC2-8 interface. Shielding this hydrophobic surface prevents promiscuous interactions of unassembled EMC2 and precludes binding of ubiquitin ligases, permitting assembly. Using biochemical reconstitution, we show that after EMC2 reaches the membrane, its interaction partners within the EMC displace WNK1, and similarly shield its exposed hydrophobic surfaces. This work describes an unexpected role for WNK1 in protein biogenesis, and defines the general requirements of an assembly factor that will apply across the proteome.

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“…Figure supplement 2;Pleiner et al 2020;Bai et al 2020;O'Donnell et al 2020;Miller-Vedam et al 2020;McDowell et al 2020)…”

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A unified evolutionary origin for the ubiquitous protein transporters SecY and YidC

Lewis

Hegde

2020

Preprint

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Cells use transporters to move protein across membranes, but the most ancient transporters’ origins are unknown. Here, we analyse the protein-conducting channel SecY and deduce a plausible path to its evolution. We find that each of its pseudosymmetric halves consists of a three-helix bundle interrupted by a two-helix hairpin. Unexpectedly, we identify this same motif in the YidC family of membrane protein biogenesis factors, which is similarly ancient as SecY. In YidC, the two-helix hairpin faces the cytosol and facilitates substrate delivery, whereas in SecY it forms the substratebinding transmembrane helices of the lateral gate. We propose that SecY originated as a YidC homolog which formed a channel by juxtaposing two hydrophilic grooves in an antiparallel homodimer. Archaeal and eukaryotic YidC family members have repurposed this interface to heterodimerise with conserved partners. Unification of the two ancient membrane protein biogenesis factors reconstructs a key step in the evolution of cells.

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Structural basis for membrane insertion by the human ER membrane protein complex

Cited by 151 publications

References 63 publications

Structural and mechanistic basis of the EMC-dependent biogenesis of distinct transmembrane clients

Structural and mechanistic basis of the EMC-dependent biogenesis of distinct transmembrane clients

Regulated assembly of the ER membrane protein complex

A unified evolutionary origin for the ubiquitous protein transporters SecY and YidC

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