Membrane Curvature

 

Membrane curvature governs lipid and protein sorting within a cell.  We have explored curvature regimes and their effect on lipid (and protein) sorting.  From these studies, we, in collaboration with F. Baginski and X. Ren (GW Mathematics), have determined that lipids sort to regions of high curvature that are dependent upon their composition ratio or fraction and not, surprisingly, on their individual characteristics (saturated or unsaturated).  In the Golgi apparatus or endoplasmic reticulum (ER), composition flux of the membrane plays a determining role in sorting instead of the acyl tail chain length or saturation of the lipid.  The coalescence of the minor fraction of lipid (and proteins) at the Golgi sacks leads to budding and vesicular transport within the cell.  Our work allows us to understand the intrinsic lipid contributions of these biological observations.

[1] S.D. Gillmor, P.S. Weiss, Dimpled Vesicles: The Interplay between Energetics and Transient Pores, Journal of Physical Chemistry B, 112 (2008) 13629-13634. (abstract)

[2] S.D. Gillmor, J.J. Heetderks, P.S. Weiss, Temperature-Dependent Vesicle Response to Surface Topography, Journal of Physical Chemistry B, 113 (2009) 11490-11495. (abstract)


[3] S. Gillmor, J. Lee, X.F. Ren, The role of Gauss curvature in a membrane phase separation problem, Physica D-Nonlinear Phenomena, 240 (2011) 1913-1927. (abstract)

[4] F.E. Baginski, R. Croce, S. Gillmor, R. Krause, Numerical investigations of the role of curvature in strong segregation problems on a given surface, Applied Mathematics and Computation, 227 (2014) 399-411. (abstract)

An example of a vesicle changing curvature at a phase boundary between Ld and Lo phases.  See ref [3] & [4].

Computation analysis of the segregation of the minority phase at the high point of curvature.  See ref [3] & [4].

Vesicle forming a dimple, similar to the red blood cell shape due to geometric confinement.  See refs [1] & [2].