title: Real-time intermembrane force measurements and imaging of lipid domain morphology during hemifusion.
abstract: Membrane fusion is the core process in membrane trafficking and is essential for cellular transport of proteins and other biomacromolecules. During protein-mediated membrane fusion, membrane proteins are often excluded from the membrane-membrane contact, indicating that local structural transformations in lipid domains play a major role. However, the rearrangements of lipid domains during fusion have not been thoroughly examined. Here using a newly developed Fluorescence Surface Forces Apparatus (FL-SFA), migration of liquid-disordered clusters and depletion of liquid-ordered domains at the membrane-membrane contact are imaged in real time during hemifusion of model lipid membranes, together with simultaneous force-distance and lipid membrane thickness measurements. The load and contact time-dependent hemifusion results show that the domain rearrangements decrease the energy barrier to fusion, illustrating the significance of dynamic domain transformations in membrane fusion processes. Importantly, the FL-SFA can unambiguously correlate interaction forces and in situ imaging in many dynamic interfacial systems.
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA.
authors.forename: Dong Woog
authors.initials: DW
authors.lastname: Lee
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA.
authors.forename: Kai
authors.initials: K
authors.lastname: Kristiansen
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA.
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Donaldson
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Cadirov
authors.affiliation: Canada Research Chair in Bio-inspired Materials and Interfaces, Faculty of Pharmacy, Université de Montréal, C.P. 6128, Succursale Centre Ville, Montréal, Quebec H3C 3J7, Canada.
authors.forename: Xavier
authors.initials: X
authors.lastname: Banquy
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA.|Department of Materials, University of California, Santa Barbara, California 93106, USA.
authors.forename: Jacob N
authors.initials: JN
authors.lastname: Israelachvili
mesh_terms: D001696:Biomechanical Phenomena; D002462:Cell Membrane / Q000502:physiology*; D008051:Lipid Bilayers; D008561:Membrane Fusion; D061848:Optical Imaging / Q000295:instrumentation*; D013050:Spectrometry, Fluorescence / Q000295:instrumentation
chemical_list: D008051:Lipid Bilayers