Molecular mechanisms of platelet exocytosis: Role of SNAP-23 and syntaxin 2 and 4 in lysosome release

Dong Chen, Paula P. Lemons, Todd Schraw, Sidney W. Whiteheart

Research output: Contribution to journalArticlepeer-review

102 Scopus citations


On stimulation by strong agonists, platelets release the contents of 3 storage compartments in 2 apparent waves of exocytosis. The first wave is the release of α- and dense core granule contents and the second is the release of lysosomal contents. Using a streptolysin O-permeabilized platelet exocytosis assay, we show that hexosaminidase release is stimulated by either Ca++ or by GTP-γ-S. This release step retains the same temporal separation from serotonin release as seen in intact platelets. This assay system was also used to dissect the molecular mechanisms of lysosome exocytosis. Lysosome release requires adenosine triphosphate and the general membrane fusion protein, N-ethylmaleimide sensitive factor. Uniquely, 2 syntaxin t-SNAREs, syntaxin 2 and 4, which localize to granules and open canalicular membranes, together with the general target membrane SNAP receptor (t-SNARE) protein SNAP-23 appear to make up the heterodimeric t-SNAREs required for lysosome exocytosis. These studies further show that regardless of stimuli (Ca++ or GTP-γ-S) serotonin and hexosaminidase release requires the same membrane fusion machinery. (C) 2000 by The American Society of Hematology.

Original languageEnglish
Pages (from-to)1782-1788
Number of pages7
Issue number5
StatePublished - Sep 1 2000

ASJC Scopus subject areas

  • Biochemistry
  • Immunology
  • Hematology
  • Cell Biology


Dive into the research topics of 'Molecular mechanisms of platelet exocytosis: Role of SNAP-23 and syntaxin 2 and 4 in lysosome release'. Together they form a unique fingerprint.

Cite this