title: Geometry of the Contact Zone between Fused Membrane-Coated Beads Mimicking Cell-Cell Fusion.
abstract: The fusion of lipid membranes is a key process in biology. It enables cells and organelles to exchange molecules with their surroundings, which otherwise could not cross the membrane barrier. To study such complex processes we use simplified artificial model systems, i.e., an optical fusion assay based on membrane-coated glass spheres. We present a technique to analyze membrane-membrane interactions in a large ensemble of particles. Detailed information on the geometry of the fusion stalk of fully fused membranes is obtained by studying the diffusional lipid dynamics with fluorescence recovery after photobleaching experiments. A small contact zone is a strong obstruction for the particle exchange across the fusion spot. With the aid of computer simulations, fluorescence-recovery-after-photobleaching recovery times of both fused and single-membrane-coated beads allow us to estimate the size of the contact zones between two membrane-coated beads. Minimizing delamination and bending energy leads to minimal angles close to those geometrically allowed.
authors.affiliation: Institut für Physikalische Chemie, Georg-August-Universität, Göttingen, Germany.
authors.forename: Filip
authors.initials: F
authors.lastname: Savić
authors.affiliation: Institut für Physikalische Chemie, Georg-August-Universität, Göttingen, Germany.
authors.forename: Torben-Tobias
authors.initials: TT
authors.lastname: Kliesch
authors.affiliation: Institut für Physikalische Chemie, Georg-August-Universität, Göttingen, Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Verbeek
authors.affiliation: Institut für Physikalische Chemie, Georg-August-Universität, Göttingen, Germany.
authors.forename: Chunxiao
authors.initials: C
authors.lastname: Bao
authors.affiliation: Drittes Physikalisches Institut, Georg-August-Universität, Göttingen, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Thiart
authors.affiliation: Leiden Institute of Chemistry, Universiteit Leiden, Leiden, The Netherlands.
authors.forename: Alexander
authors.initials: A
authors.lastname: Kros
authors.affiliation: Institut für Physikalische Chemie, Georg-August-Universität, Göttingen, Germany. Electronic address: bgeil@gwdg.de.
authors.forename: Burkhard
authors.initials: B
authors.lastname: Geil
authors.affiliation: Institut für Physikalische Chemie, Georg-August-Universität, Göttingen, Germany. Electronic address: ajansho@gwdg.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Janshoff
mesh_terms: D000465:Algorithms; D002459:Cell Fusion; D003198:Computer Simulation; D004058:Diffusion; D036681:Fluorescence Recovery After Photobleaching; D005456:Fluorescent Dyes / Q000737:chemistry; D005898:Glass; D006576:Heterocyclic Compounds, 4 or More Rings / Q000737:chemistry; D055666:Lipopeptides / Q000737:chemistry; D008561:Membrane Fusion; D008567:Membranes, Artificial; D018613:Microscopy, Confocal; D008962:Models, Theoretical; D010713:Phosphatidylcholines / Q000737:chemistry; D010714:Phosphatidylethanolamines / Q000737:chemistry; D012822:Silicon Dioxide; D014966:Xanthenes / Q000737:chemistry
chemical_list: C585841:Atto655; D005456:Fluorescent Dyes; D006576:Heterocyclic Compounds, 4 or More Rings; D055666:Lipopeptides; D008567:Membranes, Artificial; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D014966:Xanthenes; C094877:dioleoyl phosphatidylethanolamine; C007510:1,2-dipalmitoyl-3-phosphatidylethanolamine; D012822:Silicon Dioxide; C034657:Texas red; C017251:1,2-oleoylphosphatidylcholine