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Transmembrane Domain Oligomerization Propensity determined by ToxR Assay
Published on: May 26, 2011
A biphasic pulling force acts on transmembrane helices during translocon-mediated membrane integration
Nurzian Ismail1, Rickard Hedman, Nina Schiller
1Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
Nature Structural & Molecular Biology
|September 25, 2012
Summary
Researchers investigated how transmembrane helices integrate into cellular membranes. Using force sensors, they discovered significant forces are exerted on helices at two points during their passage through the translocon channel, revealing membrane integration dynamics.
Area of Science:
- Molecular Biology
- Cell Biology
- Biophysics
Background:
- Membrane proteins are crucial for cellular functions.
- Their insertion into membranes occurs co-translationally via translocons.
- The precise mechanism of transmembrane helix integration remains unclear.
Purpose of the Study:
- To elucidate the mechanism of transmembrane helix exit from the translocon.
- To understand the forces acting on transmembrane helices during membrane integration.
Main Methods:
- Utilized translation-arrest peptides from bacterial SecM and mammalian Xbp1 as force sensors.
- Investigated force exertion on transmembrane helices during translocon transit.
Main Results:
- Identified substantial force exerted on transmembrane helices at two distinct points within the translocon channel.
- Provided direct evidence for forces guiding helix movement during membrane integration.
Conclusions:
- The study offers novel insights into the dynamics of co-translational membrane protein insertion.
- Force exertion is a key factor in the lateral exit of transmembrane helices from translocons.
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