Recently, we have found that the fraction of phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) which is two-dimensionally mobile within a supported lipid bilayer on a planar glass substrate decreases over time. By using a novel bilayer leaflet decoupling assay, dubbed “bilayer unzipping”, it was possible to correlate the decreasing mobile fraction with an increased population of PI(4,5)P2 in the lower leaflet of the membrane. Moreover, it could be shown that PI(4,5)P2 underwent leaflet flipping at membrane defect sites. In this talk, we will explore the mechanism behind these “flipping and trapping” events. Specifically, with data obtained from fluorescence recovery after photobleaching (FRAP) experiments, we will discuss: (1) the types of interactions between lipid head groups and the planar substrate, (2) the structural basis for these interactions and (3) the parameters that can be employed to adjust the interaction energies, and as a result, modulate the mobility of lipid molecules on the substrate.

Modulation of lipid mobility by tuning lipid-substrate interactions

ACS Spring Meeting 2021

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