Scaling relations of elastic and structural properties in cholesterol-rich lipid membranes

ORAL

Abstract

The elastic properties of cell membranes play a key role in cell functions. Cholesterol – an essential component of eukaryotic cell membranes– is known to cause lipid condensation or a decrease in the average area per lipid (AL). However, the interplay between cholesterol-driven lipid packing and emergent elastic properties of lipid membranes remains largely unexplored. Theories based on mean field calculations have predicted different dependences of the membrane bending modulus, κ, and the area compressibility modulus, KA, on AL. Here, we examine these relations in cholesterol-rich lipid membranes with various degrees of acyl chain unsaturation using neutron spin-echo spectroscopy (NSE), solid-state 2H NMR relaxometry, and molecular dynamics simulations. We find that cholesterol stiffens all studied membranes irrespective of the degree of chain unsaturation over the accessible length and time scales, with an inverse dependence of κ and KA on AL. To generalize the molecular mechanisms driving this dependence, we consider normalized variables that eliminate experimental factors leading to different observed values of elastic membrane parameters. These structure-property relations inform design rules for engineered membranes and artificial cells with real-world functionalities.

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Presenters

  • Teshani Kumarage

    • Department of Physics and Center for Soft Matter & Biological Physics, Virginia Tech, Blacksburg, VA 24061, USA
    • Virginia Tech

Authors

  • Teshani Kumarage

    • Department of Physics and Center for Soft Matter & Biological Physics, Virginia Tech, Blacksburg, VA 24061, USA
    • Virginia Tech

  • Sudipta Gupta

    • Department of Physics and Center for Soft Matter and Biological Physics, Virginia Tech
    • Department of Physics and Center for Soft Matter & Biological Physics, Virginia Tech, Blacksburg, VA 24061, USA

  • Fathima T Doole

    • Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA

  • Milka Doktorova

    • University of Virginia
    • Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22904, USA

  • Haden Scott

    • Neutron Scattering Division and Shull Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA

  • Laura-Roxana Stingaciu

    • Oak Ridge National Lab
    • Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA

  • John Katsaras

    • Neutron Scattering Division and Shull Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA

  • George Khelashvili

    • Department of Physiology and Biophysics and Institute of Computational Biomedicine, Weill Cornell Medical College, New York, NY 10065

  • Michael F Brown

    • Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA

  • Rana Ashkar

    • Department of Physics and Center for Soft Matter and Biological Physics, Virginia Tech
    • Virginia Tech
    • Department of Physics and Center for Soft Matter & Biological Physics, Virginia Tech, Blacksburg, VA 24061, USA