Dynamics of Membrane Tubes Formed by I-BARS

Abstract

Cells must be able to maintain and change membrane shape. This membrane curvature can be influenced by any lateral phase heterogeneity. Ternary mixtures of high-melting lipid, low-melting lipid, and cholesterol exhibit a region of liquid-ordered (Lo)þ liquid-disordered (Ld) phase coexistence analogous to raft þ non-raft behavior in cells. Although curvature can induce separation and sorting in vitro, a number of highly-curved membranes in vivo have raft-like composition, which is puzzling since the raft-like compositions have greater rigidity in lipid model mixtures. We find that including transmembrane helical