title: Ectopic expression of syntaxin 1 in the ER redirects TI-VAMP- and cellubrevin-containing vesicles.
abstract: SNARE proteins are key mediators of membrane fusion. Their function in ensuring compartmental specificity of membrane fusion has been suggested by in vitro studies but not demonstrated in vivo. We show here that ectopic expression of the plasma membrane t-SNARE heavy chain syntaxin 1 in the endoplasmic reticulum induces the redistribution of its cognate vesicular SNAREs, TI-VAMP and cellubrevin, and its light chain t-SNARE SNAP-23. These effects were prevented by co-expressing nSec1. Expression of syntaxin 1 alone impaired the cell surface expression of TI-VAMP and cellubrevin but not the recycling of transferrin receptor. TI-VAMP, cellubrevin and SNAP-23 associated in vivo with exogenous syntaxin 1. Redistribution of TI-VAMP in the ER of syntaxin-1-expressing cells was microtubule dependent and impaired the trafficking of CD63, a cargo of TI-VAMP-containing vesicles. We conclude that the destination of v-SNAREs is driven by their specific interaction with cognate t-SNAREs. Our in vivo data provide strong support for the theory that highly specific v-SNARE-t-SNARE interactions control compartmental specificity of membrane fusion.
authors.affiliation: Membrane Traffic and Neuronal Plasticity, INSERM U536, Institut du Fer-à-Moulin, 75005 Paris, France.
authors.forename: Sonia
authors.initials: S
authors.lastname: Martinez-Arca
authors.forename: Veronique
authors.initials: V
authors.lastname: Proux-Gillardeaux
authors.forename: Philipp
authors.initials: P
authors.lastname: Alberts
authors.forename: Daniel
authors.initials: D
authors.lastname: Louvard
authors.forename: Thierry
authors.initials: T
authors.lastname: Galli
mesh_terms: D015703:Antigens, CD / Q000378:metabolism; D000954:Antigens, Surface / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D002451:Cell Compartmentation / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008561:Membrane Fusion / Q000502:physiology*; D008565:Membrane Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D051938:Munc18 Proteins; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; D050683:R-SNARE Proteins; D011990:Receptors, Transferrin / Q000378:metabolism; D050600:SNARE Proteins; D050827:Syntaxin 1; D060149:Tetraspanin 30; D022161:Transport Vesicles / Q000378:metabolism*; D051040:Vesicle-Associated Membrane Protein 3; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D015703:Antigens, CD; D000954:Antigens, Surface; C554586:CD63 protein, human; D002352:Carrier Proteins; D008565:Membrane Proteins; D051938:Munc18 Proteins; D009419:Nerve Tissue Proteins; D010980:Platelet Membrane Glycoproteins; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; D050683:R-SNARE Proteins; D011990:Receptors, Transferrin; C100493:SNAP23 protein, human; D050600:SNARE Proteins; C494212:STX1A protein, human; D050827:Syntaxin 1; D060149:Tetraspanin 30; C121241:VAMP7 protein, human; D051040:Vesicle-Associated Membrane Protein 3; D033921:Vesicular Transport Proteins