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Transverse Lipid Organization Dictates Bending Fluctuations in Model Plasma Membranes



Brett W. Rickeard, Michael H. Nguyen, Mitchell DiPasquale, Caesar G. Yip, Hamilton Baker, Frederick A. Heberle, Xiaobing Zuo, Elizabeth Kelley, Michihiro Nagao, Drew Marquardt


Bending fluctuation is one of the most important dynamic modes of lipid membranes. These fluctuations play a vital role in many biological processes, most notoriously, contributing to the regulation of membrane protein activity. We investigated the bending rigidity (K) of liposomes with an asymmetric transbilayer distribution of high- and low-melting liquids (asymmetric large unilamellar vesiclesm aLUVs) using neutron spin-echo (NSE) spectroscopy. The aLUVs were generated using cyclodextrin-catalyzed lipid exchange and were composed of an egg sphingomyelin (ESM) enriched outer leaflet (Xesm = 0.42) and a 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) inner leaflet (XPOPE = 0.94). Using NSE techniques, the aLUVs were measured at three temperature conditions where ESM and POPE are both gel, ESM is gel and POPE is fluid and finally both ESM and POPE are fluid. Under these conditions we find that the asymmetric organization of lipid increases the overall strength of the bending fluctuations, thus giving direct physical evidence of lipid-driven interleaflet coupling.


asymmetric lipid membrane, bending fluctuations, small angle scattering, neutron spin echo


Rickeard, B. , Nguyen, M. , DiPasquale, M. , Yip, C. , Baker, H. , Heberle, F. , Zuo, X. , Kelley, E. , Nagao, M. and Marquardt, D. (2020), Transverse Lipid Organization Dictates Bending Fluctuations in Model Plasma Membranes, Nanoscale, [online], (Accessed April 14, 2024)
Created January 20, 2020, Updated October 12, 2021