Vesicle-associated membrane protein 3 (VAMP-3) and VAMP-8 are present in human platelets and are required for granule secretion

Blood. 2002 Aug 1;100(3):1081-3. doi: 10.1182/blood.v100.3.1081.

Abstract

Secretion of platelet granules is necessary for normal hemostasis. Platelet secretion requires soluble N-ethylmaleimide-sensitive factor attachment protein (SNAP) receptor (SNARE) complex formation between different members of the syntaxin, SNAP-25, and vesicle-associated membrane protein (VAMP) gene families. Using microcapillary reverse-phase high-performance liquid chromatography-nano-electrospray tandem mass spectrometry, we identified VAMP-3 and VAMP-8 as VAMP isoforms coimmunoprecipitated from platelets with syntaxin 4. Immunoblotting experiments confirmed the presence of VAMP-3 and VAMP-8 but not VAMP-1 or VAMP-2 in platelets. To examine the effect of VAMP proteins on platelet secretion, soluble recombinant (r) VAMP-2, rVAMP-3, and rVAMP-8 were incubated with streptolysin O-permeabilized platelets. Secretion of alpha granules (monitored by flow cytometric measurement of P-selectin) was blocked, and dense-granule secretion (assessed by release of carbon 14-serotonin) was almost completely inhibited by rVAMP-3, whereas rVAMP-8 inhibited secretion of dense granules but not alpha granules. In contrast, rVAMP-2, which formed SNARE complexes in vitro, had no effect on platelet exocytosis. We conclude that VAMP-3 and VAMP-8 form SNARE complexes with platelet syntaxin 4 and are required for platelet granule secretion.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Blood Platelets / chemistry
  • Blood Platelets / metabolism*
  • Blood Platelets / ultrastructure
  • Cell Membrane Permeability
  • Cytoplasmic Granules / metabolism
  • Cytoplasmic Granules / physiology
  • Exocytosis / physiology*
  • Humans
  • Membrane Proteins / metabolism
  • Membrane Proteins / physiology*
  • Precipitin Tests
  • Protein Binding
  • Qa-SNARE Proteins
  • R-SNARE Proteins
  • SNARE Proteins
  • Vesicle-Associated Membrane Protein 3
  • Vesicular Transport Proteins*

Substances

  • Membrane Proteins
  • Qa-SNARE Proteins
  • R-SNARE Proteins
  • SNARE Proteins
  • VAMP8 protein, human
  • Vesicle-Associated Membrane Protein 3
  • Vesicular Transport Proteins