Membrane fusion: stalk model revisited.
Membrane fusion is believed to proceed via intermediate structures called stalks. Mathematical analysis of the stalk provided the elastic energy involved in this structure and predicted the possible evolution of the overall process, but the energies predicted by the original model were suspiciously high. This was due to an erroneous assumption, i.e., that the stalk has a figure of revolution of a circular arc. Here we abandon this assumption and calculate the correct shape of the stalk. We find that it can be made completely stress free and, hence, its energy, instead of being positive and high can become negative, thus facilitating the fusion process. Based on our new calculations, the energies of hemifusion, of complete fusion, and of the pore in a bilayer were analyzed. Implications for membrane fusion and lipid phase transitions are discussed.
Markin
Vladislav S
VS
Department of Anesthesiology, University of Texas Southwestern, Dallas, Texas 75390, USA. vladislav.markin@utsouthwestern.edu
Albanesi
Joseph P
JP
D055592:Biophysical Phenomena; D001703:Biophysics; D002462:Cell Membrane / Q000737:chemistry*; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry; D008561:Membrane Fusion; D008563:Membrane Lipids / Q000737:chemistry; D008954:Models, Biological; D008962:Models, Theoretical; D013816:Thermodynamics
D008051:Lipid Bilayers; D008563:Membrane Lipids