Structural and mechanistic basis of the EMC-dependent biogenesis of distinct transmembrane clients
- Whitehead Institute for Biomedical Research, United States
- Max Plank Institute for Biochemistry, Germany
- University of California, San Francisco, United States
- Max Planck Institute of Biochemistry, Germany
- FairJourney Biologics, Portugal
- Stanford University, United States
- St Jude Children's Research Hospital, United States
Abstract
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.
Data availability
All data generated or analyzed during this study are included in the manuscript or will have been made available in public repositories. Flow cytometry data and analysis code is available at Github (https://github.com/katerinadpopova/emcstructurefunction). Electron microscopy maps are available at the EMDB (unsharpened, sharpened, half maps, FSC file) (accession codes EMDB - 11732, 11733, 23003, 23033), models at the PDB (accession codes PDB - 7ADO, 7ADP, 7KRA, 7KTX), and raw cryo-EM data at EMPIAR. Key Resource Table is included as an appendix to the main article and is referenced throughout the Methods section with relevant reagents used or generated during the course of the study allowing for replication of these or request of specific cell lines and reagents. Supplementary file 1 contains raw mass spectrometry data. Supplementary file 4 contains un-cropped western blots. Supplementary file 5 contains plasmid sequences for mutant constructs generated for this study.
Article and author information
Author details
Lakshmi E Miller-Vedam
Elizabeth A Boydston
Matthew J Shurtleff
Jonathan S Weissman
Funding
Deutsche Forschungsgemeinschaft
- Brenda A Schulman
Chan Zuckerberg Initiative
- Adam Frost
Max Planck Institute for Dynamics of Complex Technical Systems Magdeburg
- Brenda A Schulman
National Institutes of Health (P50AI150476,1P41CA196276-01)
- Natalia Sevillano
- Charles S Craik
Helen Hay Whitney Foundation
- Matthew J Shurtleff
Peter und Traudl Engelhorn Stiftung
- Bastian Bräuning
Jane Coffin Childs Memorial Fund for Medical Research
- Nicole T Schirle Oakdale
National Institutes of Health (1DP2OD017690-01)
- Adam Frost
National Institutes of Health (GM24485)
- Robert M Stroud
Howard Hughes Medical Institute
- Jonathan S Weissman
The funders had no role in study design, data collection, data interpretation, or the decision to submit the work for publication.
Copyright
© 2020, Miller-Vedam et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Structural and mechanistic basis of the EMC-dependent biogenesis of distinct transmembrane clients
eLife 9:e62611.
https://doi.org/10.7554/eLife.62611
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