King's College London

Research portal

The membrane transporter lactose permease increases lipid bilayer bending rigidity

Research output: Contribution to journalArticlepeer-review

Nestor Lopez Mora, Heather E. Findlay, Nicholas J. Brooks, Sowmya Purushothaman, Oscar Ces, Paula J. Booth

Original languageEnglish
Pages (from-to)3787-3794
Number of pages8
JournalBiophysical Journal
Volume120
Issue number17
DOIs
Accepted/In press2021
Published7 Sep 2021

Bibliographical note

Funding Information: P.J.B. acknowledges financial support from European Research Council Advanced Grant 294342 , Wellcome Trust Investigator Award 214259/Z/18/Z , and King’s College London . Confocal imaging was conducted in the Nikon Imaging Centre at King’s College London. Funding Information: N.L.M. acknowledges Dr. Yuval Elani for the insightful discussions on fluctuation analysis. P.J.B. acknowledges financial support from European Research Council Advanced Grant 294342, Wellcome Trust Investigator Award 214259/Z/18/Z, and King's College London. Confocal imaging was conducted in the Nikon Imaging Centre at King's College London. Publisher Copyright: © 2021 Biophysical Society Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

King's Authors

Abstract

Cellular life relies on membranes, which provide a resilient and adaptive cell boundary. Many essential processes depend upon the ease with which the membrane is able to deform and bend, features that can be characterized by the bending rigidity. Quantitative investigations of such mechanical properties of biological membranes have primarily been undertaken in solely lipid bilayers and frequently in the absence of buffers. In contrast, much less is known about the influence of integral membrane proteins on bending rigidity under physiological conditions. We focus on an exemplar member of the ubiquitous major facilitator superfamily of transporters and assess the influence of lactose permease on the bending rigidity of lipid bilayers. Fluctuation analysis of giant unilamellar vesicles (GUVs) is a useful means to measure bending rigidity. We find that using a hydrogel substrate produces GUVs that are well suited to fluctuation analysis. Moreover, the hydrogel method is amenable to both physiological salt concentrations and anionic lipids, which are important to mimic key aspects of the native lactose permease membrane. Varying the fraction of the anionic lipid in the lipid mixture DOPC/DOPE/DOPG allows us to assess the dependence of membrane bending rigidity on the topology and concentration of an integral membrane protein in the lipid bilayer of GUVs. The bending rigidity gradually increases with the incorporation of lactose permease, but there is no further increase with greater amounts of the protein in the membrane.

View graph of relations

© 2020 King's College London | Strand | London WC2R 2LS | England | United Kingdom | Tel +44 (0)20 7836 5454