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Updated: Aug 24, 2025
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Single-Molecule Diffusion and Assembly on Polymer-Crowded Lipid Membranes
Published on: July 19, 2022
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Substrate-driven assembly of a translocon for multipass membrane proteins
Arunkumar Sundaram1, Melvin Yamsek1, Frank Zhong2
1Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA.
Nature
|October 19, 2022
Summary
Researchers identified a specialized
Area of Science:
- Cell Biology
- Molecular Biology
- Protein Biogenesis
Background:
- Most membrane proteins are synthesized on endoplasmic reticulum (ER)-bound ribosomes at the translocon.
- The mechanism by which the translocon accommodates diverse substrates is poorly understood.
Purpose of the Study:
- To define the composition, function, and assembly of a translocon specialized for multipass membrane protein biogenesis.
- To elucidate how nascent multipass proteins recruit this specialized translocon.
Main Methods:
- Analysis of insertion intermediates.
- Reconstitution studies.
- Analysis of cells lacking multipass translocon components.
Main Results:
- Identified a 'multipass translocon' composed of GET- and EMC-like (GEL), protein associated with translocon (PAT), and back of Sec61 (BOS) complexes.
- Nascent chain features trigger multipass translocon assembly.
- Multipass translocon components are crucial for protein topogenesis and stability.
Conclusions:
- Established the mechanism of selective multipass translocon recruitment by nascent multipass proteins.
- The ER translocon is a dynamic assembly that adjusts subunit composition co-translationally.
- This dynamic assembly accommodates diverse substrate biosynthetic needs.
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