Transport of sterols within and between cellular membranes is a process of fundamental importance to sterol trafficking and homeostasis. To traverse a lipid bilayer, a sterol molecule must first enter the bilayer from solution (import), move between leaflets (flip-flop) and then exit the distal leaflet into solution (export). A number of studies have sought to determine the rates of these processes, both in vivo and in vitro, yet controversy remains on some points, particularly rate of flip-flop. Using SANS with fully deuterated ergosterol as a probe, and FRET with 9,11-dehydroergosterol (DHE) as a donor, we have measured overall vesicle-to-vesicle transport rates under quasi-equilibrium conditions. Multiple kinetic models were tested against the data to understand the contribution of several microscopic processes to the overall rate. The results of these studies, along with their implications for future studies and biological processes, will be presented.

Sterol transfer rates measured by small-angle neutron scattering (SANS) and fluorescence resonance energy transfer (FRET)

245th National Meeting (2013)

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