title: Liposome reconstitution of a minimal protein-mediated membrane fusion machine.
abstract: Biological membrane fusion is dependent on protein catalysts to mediate localized restructuring of lipid bilayers. A central theme in current models of protein-mediated membrane fusion involves the sequential refolding of complex homomeric or heteromeric protein fusion machines. The structural features of a new family of fusion-associated small transmembrane (FAST) proteins appear incompatible with existing models of membrane fusion protein function. While the FAST proteins function to induce efficient cell-cell fusion when expressed in transfected cells, it was unclear whether they function on their own to mediate membrane fusion or are dependent on cellular protein cofactors. Using proteoliposomes containing the purified p14 FAST protein of reptilian reovirus, we now show via liposome-cell and liposome-liposome fusion assays that p14 is both necessary and sufficient for membrane fusion. Stoichiometric and kinetic analyses suggest that the relative efficiency of p14-mediated membrane fusion rivals that of the more complex cellular and viral fusion proteins, making the FAST proteins the simplest known membrane fusion machines.
authors.affiliation: Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Deniz
authors.initials: D
authors.lastname: Top
authors.forename: Roberto
authors.initials: R
authors.lastname: de Antueno
authors.forename: Jayme
authors.initials: J
authors.lastname: Salsman
authors.forename: Jennifer
authors.initials: J
authors.lastname: Corcoran
authors.forename: Jamie
authors.initials: J
authors.lastname: Mader
authors.forename: David
authors.initials: D
authors.lastname: Hoskin
authors.forename: Ahmed
authors.initials: A
authors.lastname: Touhami
authors.forename: Manfred H
authors.initials: MH
authors.lastname: Jericho
authors.forename: Roy
authors.initials: R
authors.lastname: Duncan
mesh_terms: D000818:Animals; D017209:Apoptosis; D002478:Cells, Cultured; D016503:Drug Delivery Systems; D006801:Humans; D007781:Lactoferrin / Q000008:administration & dosage / Q000494:pharmacology; D008081:Liposomes / Q000737:chemistry; D008561:Membrane Fusion / Q000502:physiology*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D010455:Peptides / Q000494:pharmacology; D011510:Proteolipids / Q000737:chemistry; D012087:Reoviridae / Q000737:chemistry; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D008081:Liposomes; D008565:Membrane Proteins; D010455:Peptides; D011510:Proteolipids; D014764:Viral Proteins; C020485:proteoliposomes; D007781:Lactoferrin