title: Assembly of Weibel-Palade body-like tubules from N-terminal domains of von Willebrand factor.
abstract: Endothelial cells assemble von Willebrand factor (VWF) multimers into ordered tubules within storage organelles called Weibel-Palade bodies, and tubular packing is necessary for the secretion of VWF filaments that can bind connective tissue and recruit platelets to sites of vascular injury. We now have recreated VWF tubule assembly in vitro, starting with only pure VWF propeptide (domains D1D2) and disulfide-linked dimers of adjacent N-terminal D'D3 domains. Assembly requires low pH and calcium ions and is reversed at neutral pH. Quick-freeze deep-etch electron microscopy and three-dimensional reconstruction of negatively stained images show that tubules contain a repeating unit of one D'D3 dimer and two propeptides arranged in a right-handed helix with 4.2 units per turn. The symmetry and location of interdomain contacts suggest that decreasing pH along the secretory pathway coordinates the disulfide-linked assembly of VWF multimers with their tubular packaging.
authors.affiliation: Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Ren-Huai
authors.initials: RH
authors.lastname: Huang
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Robyn
authors.initials: R
authors.lastname: Roth
authors.forename: Xiong
authors.initials: X
authors.lastname: Yu
authors.forename: Angie R
authors.initials: AR
authors.lastname: Purvis
authors.forename: John E
authors.initials: JE
authors.lastname: Heuser
authors.forename: Edward H
authors.initials: EH
authors.lastname: Egelman
authors.forename: J Evan
authors.initials: JE
authors.lastname: Sadler
mesh_terms: D019281:Dimerization; D004220:Disulfides / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007477:Ions; D007834:Lasers; D008027:Light; D008854:Microscopy, Electron; D010455:Peptides / Q000737:chemistry; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D012542:Scattering, Radiation; D020302:Weibel-Palade Bodies / Q000737:chemistry* / Q000502:physiology; D014841:von Willebrand Factor / Q000737:chemistry*
chemical_list: D004220:Disulfides; D007477:Ions; D010455:Peptides; D014841:von Willebrand Factor