Interview for Faculty Position

Lipid rafts reach a critical point

Sarah Veatch

Cornell University

Multicomponent lipid bilayer membranes can contain two coexisting liquid phases, named liquid-ordered and liquid-disordered. Recently, we demonstrated that large (micron-scale) and dynamic critical fluctuations are found in ‘simple’ ternary bilayer membranes prepared with critical compositions. Remarkably, robust critical behavior is also found in compositionally complex biomembrane vesicles isolated directly from living cell plasma membranes. This finding strongly suggests that cells tightly regulate plasma membrane protein and lipid content to reside near a critical point at physiological temperatures. Critical fluctuations may provide a physical basis of functional membrane heterogeneity in living cells. Current work focuses on characterizing the lateral organization of proteins and lipids on the intact cell surface and investigating possible functional implications of critical behavior in membrane biology.