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Entropic Tension in Crowded Membranes

Lindén, Martin and Sens, Pierre and Phillips, Rob (2012) Entropic Tension in Crowded Membranes. PLoS Computational Biology, 8 (3). Art. no. e1002431. ISSN 1553-734X. PMCID PMC3305330. doi:10.1371/journal.pcbi.1002431. https://resolver.caltech.edu/CaltechAUTHORS:20120501-131827231

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Abstract

Unlike their model membrane counterparts, biological membranes are richly decorated with a heterogeneous assembly of membrane proteins. These proteins are so tightly packed that their excluded area interactions can alter the free energy landscape controlling the conformational transitions suffered by such proteins. For membrane channels, this effect can alter the critical membrane tension at which they undergo a transition from a closed to an open state, and therefore influence protein function in vivo. Despite their obvious importance, crowding phenomena in membranes are much less well studied than in the cytoplasm. Using statistical mechanics results for hard disk liquids, we show that crowding induces an entropic tension in the membrane, which influences transitions that alter the projected area and circumference of a membrane protein. As a specific case study in this effect, we consider the impact of crowding on the gating properties of bacterial mechanosensitive membrane channels, which are thought to confer osmoprotection when these cells are subjected to osmotic shock. We find that crowding can alter the gating energies by more than 2 k_(B)T in physiological conditions, a substantial fraction of the total gating energies in some cases. Given the ubiquity of membrane crowding, the nonspecific nature of excluded volume interactions, and the fact that the function of many membrane proteins involve significant conformational changes, this specific case study highlights a general aspect in the function of membrane proteins.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1371/journal.pcbi.1002431DOIArticle
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3305330/PubMed CentralArticle
ORCID:
AuthorORCID
Phillips, Rob0000-0003-3082-2809
Additional Information:© 2012 Lindén et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Received October 14, 2011; Accepted February 1, 2012; Published March 15, 2012. Editor: Emad Tajkhorshid, University of Illinois, United States of America. This study was funded by the National Institutes of Health through NIH Award number R01 GM084211 and the Directors Pioneer Award, grant DP1 OD000217A (R.P. and M.L.) www.nih.gov, La Fondation Pierre Gilles de Gennes (R.P. and P.S.) www.fondation-pgg.org, the Wenner-Gren foundations (M.L.) www.swgc.org and the Foundations of the Royal Swedish Academy of Sciences (M.L.) www.kva.se. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We are grateful to KC Huang, Jane Kondev, Doug Rees, Matthew Turner, Tristan Ursell and Paul Wiggins for insightful discussions. Author Contributions: Conceived and designed the experiments: ML PS RP. Performed the experiments: ML PS RP. Analyzed the data: ML. Wrote the paper: ML PS RP.
Funders:
Funding AgencyGrant Number
NIHR01 GM084211
NIHDP1 OD000217A
Fondation Pierre Gilles de GennesUNSPECIFIED
Foundations of the Royal Swedish Academy of SciencesUNSPECIFIED
Wenner-Gren FoundationsUNSPECIFIED
Issue or Number:3
PubMed Central ID:PMC3305330
DOI:10.1371/journal.pcbi.1002431
Record Number:CaltechAUTHORS:20120501-131827231
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20120501-131827231
Official Citation:Lindén M, Sens P, Phillips R (2012) Entropic Tension in Crowded Membranes. PLoS Comput Biol 8(3): e1002431. doi:10.1371/journal.pcbi.1002431
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:31254
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:02 May 2012 20:43
Last Modified:09 Nov 2021 19:48

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