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Emerging Patterns in Membrane Protein Folding Pathways

delete2025-05-06
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PRE
AI
S
Sang Ah Kim
H
Hyun Gyu Kim
W
W.C. Bhashini Wijesinghe
D
Duyoung Min *
T
Tae‐Young Yoon
DOI:10.1146/annurev-biophys-070524-100658delete
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Abstract

Abstract

En 中文
Studies of membrane protein folding have progressed from simple systems such as bacteriorhodopsin to complex structures such as ATP-binding cassette transporters and voltage-gated ion channels. Advances in techniques such as single-molecule force spectroscopy and in vivo force profiling now allow for the detailed examination of membrane protein folding pathways at amino acid resolutions. These proteins navigate rugged energy landscapes partly shaped by the absence of hydrophobic collapse and the viscous nature of the lipid bilayer, imposing biophysical limitations on folding speeds. Furthermore, many transmembrane (TM) helices display reduced hydrophobicity to support functional requirements, simultaneously increasing the energy barriers for membrane insertion, a manifestation of the evolutionary trade-off between functionality and fold-ability. These less hydrophobic TM helices typically insert and fold as helical hairpins, following the protein synthesis direction from the N terminus to the C terminus, with assistance from endoplasmic reticulum (ER) chaperones like the Sec61 translocon and the ER membrane protein complex. The folding pathways of multidomain membrane proteins are defined by allosteric networks that extend across various domains, where mutations and folding correctors affect seemingly distant domains. A common evolutionary strategy is likely to be domain specialization, where N-terminal domains enhance foldability and C-terminal domains enhance functionality. Thus, despite inherent biophysical constraints, evolution has finely tuned membrane protein sequences to optimize foldability, stability, and functionality.
Keywords:
membrane protein folding
single-molecule force spectroscopy
helical
hairpin
templated folding
multidomain membrane protein

Journal

Annual Review of Biophysics cover
Annual Review of Biophysics
IF:
13.7
Papers:
361
Citations:
4.2K

Organization

S
Seoul Natl Univ
Scholars:
4.1K
Papers: 1.9K
Citations: 590
U
Ulsan National Institute of Science and Technology
Scholars:
437
Papers: 183
Citations: 32