Syntaxin 5 determines Weibel-Palade body size and von Willebrand factor secretion by controlling Golgi architecture
Marije Kat,
Ellie Karampini,
Arie J. Hoogendijk,
Petra E. Bürgisser,
Aat A. Mulder,
Floris P.J. van Alphen,
Jenny Olins,
Dirk Geerts,
Maartje van den Biggelaar,
Coert Margadant,
Jan Voorberg,
Ruben Bierings
Affiliations
Marije Kat
Molecular Hematology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Center, University of Amsterdam
Ellie Karampini
Molecular Hematology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Center, University of Amsterdam, The Netherlands; Vascular Biology, Royal College of Surgeons, Dublin
Arie J. Hoogendijk
Molecular Hematology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Center, University of Amsterdam
Petra E. Bürgisser
Hematology, Erasmus University Medical Center, Rotterdam
Aat A. Mulder
Molecular Cell Biology, Leiden University Medical Center, Leiden
Floris P.J. van Alphen
Molecular Hematology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Center, University of Amsterdam
Jenny Olins
Molecular Hematology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Center, University of Amsterdam
Dirk Geerts
Medical Biology, Amsterdam University Medical Center, location AMC, University of Amsterdam
Maartje van den Biggelaar
Molecular Hematology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Center, University of Amsterdam
Coert Margadant
Angiogenesis Laboratory, Cancer Center Amsterdam, Amsterdam University Medical Center, location VUmc
Jan Voorberg
Molecular Hematology, Sanquin Research and Landsteiner Laboratory, Amsterdam University Medical Center, University of Amsterdam, The Netherlands; Experimental Vascular Medicine, Amsterdam University Medical Center, University of Amsterdam
Ruben Bierings
Hematology, Erasmus University Medical Center, Rotterdam
Von Willebrand factor (VWF) is a multimeric hemostatic protein primarily synthesized in endothelial cells. VWF is stored in endothelial storage organelles, the Weibel-Palade bodies (WPB), whose biogenesis strongly depends on VWF anterograde trafficking and Golgi architecture. Elongated WPB morphology is correlated to longer VWF strings with better adhesive properties. We previously identified the SNARE SEC22B, which is involved in anterograde endoplasmic reticulum-to-Golgi transport, as a novel regulator of WPB elongation. To elucidate novel determinants of WPB morphology we explored endothelial SEC22B interaction partners in a mass spectrometry-based approach, identifying the Golgi SNARE Syntaxin 5 (STX5). We established STX5 knockdown in endothelial cells using shRNA-dependent silencing and analyzed WPB and Golgi morphology, using confocal and electron microscopy. STX5-depleted endothelial cells exhibited extensive Golgi fragmentation and decreased WPB length, which was associated with reduced intracellular VWF levels, and impaired stimulated VWF secretion. However, the secretion-incompetent organelles in shSTX5 cells maintained WPB markers such as Angiopoietin 2, P-selectin, Rab27A, and CD63. In brief, we identified SNARE protein STX5 as a novel regulator of WPB biogenesis.
