title: Initiation and dynamics of hemifusion in lipid bilayers.
abstract: One approach to the understanding of fusion in cells and model membranes involves stalk formation and expansion of the hemifusion diaphragm. We predict theoretically the initiation of hemifusion by stalk expansion and the dynamics of mesoscopic hemifusion diaphragm expansion in the light of recent experiments and theory that suggested that hemifusion is driven by intramembrane tension far from the fusion zone. Our predictions include a square-root scaling of the hemifusion zone size on time as well as an estimate of the minimal tension for initiation of hemifusion. Whereas a minimal amount of pressure is evidently needed for stalk formation, it is not necessarily required for stalk expansion. The energy required for tension-induced fusion is much smaller than that required for pressure-driven fusion.
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel. guy.hed@weizmann.ac.il
authors.forename: Guy
authors.initials: G
authors.lastname: Hed
authors.forename: S A
authors.initials: SA
authors.lastname: Safran
mesh_terms: D003198:Computer Simulation; D017276:Friction; D008051:Lipid Bilayers / Q000737:chemistry*; D046911:Macromolecular Substances; D008560:Membrane Fluidity; D008561:Membrane Fusion; D008567:Membranes, Artificial; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D013500:Surface Tension; D014783:Viscosity; D014867:Water / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D046911:Macromolecular Substances; D008567:Membranes, Artificial; D014867:Water