title: VAMP3 is associated with endothelial weibel-palade bodies and participates in their Ca(2+)-dependent exocytosis.
abstract: Weibel-Palade bodies (WPBs) are secretory organelles of endothelial cells that store the thrombogenic glycoprotein von Willebrand factor (vWF). Endothelial activation, e.g. by histamine and thrombin, triggers the Ca(2+)-dependent exocytosis of WPB that releases vWF into the vasculature and thereby initiates platelet capture and thrombus formation. Towards understanding the molecular mechanisms underlying this regulated WPB exocytosis, we here identify components of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) machinery associated with WPB. We show that vesicle-associated membrane protein (VAMP) 3 and VAMP8 are present on WPB and that VAMP3, but not VAMP8 forms a stable complex with syntaxin 4 and SNAP23, two plasma membrane-associated SNAREs in endothelial cells. By introducing mutant SNARE proteins into permeabilized endothelial cells we also show that soluble VAMP3 but not VAMP8 mutants comprising the cytoplasmic domain interfere with efficient vWF secretion. This indicates that endothelial cells specifically select VAMP 3 over VAMP8 to cooperate with syntaxin 4 and SNAP23 in the Ca(2+)-triggered fusion of WPB with the plasma membrane. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.
authors.affiliation: Institute of Medical Biochemistry, Centre for Molecular Biology of Inflammation, University of Münster, D-48149 Münster, Germany.
authors.forename: Inés Rojo
authors.initials: IR
authors.lastname: Pulido
authors.forename: Reinhard
authors.initials: R
authors.lastname: Jahn
authors.forename: Volker
authors.initials: V
authors.lastname: Gerke
mesh_terms: D001426:Bacterial Proteins / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002463:Cell Membrane Permeability / Q000187:drug effects; D042783:Endothelial Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D005089:Exocytosis / Q000187:drug effects; D005799:Genes, Dominant / Q000235:genetics; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D021381:Protein Transport / Q000187:drug effects; D050765:Qa-SNARE Proteins / Q000378:metabolism; D050766:Qb-SNARE Proteins / Q000378:metabolism; D050767:Qc-SNARE Proteins / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D013301:Streptolysins / Q000494:pharmacology; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D014471:Umbilical Veins / Q000166:cytology; D051040:Vesicle-Associated Membrane Protein 3 / Q000378:metabolism*; D020302:Weibel-Palade Bodies / Q000187:drug effects / Q000378:metabolism*; D014841:von Willebrand Factor / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; D034741:RNA, Small Interfering; C100493:SNAP23 protein, human; D013301:Streptolysins; C494946:VAMP3 protein, human; D051040:Vesicle-Associated Membrane Protein 3; C025964:streptolysin O; D014841:von Willebrand Factor; D006632:Histamine; D002118:Calcium