Platelet Secretion and Hemostasis Require Syntaxin-binding Protein STXBP5

Authors

Shaojing Ye, University of KentuckyFollow
Yunjie Huang, University of KentuckyFollow
Smita Joshi, University of KentuckyFollow
Jinchao Zhang, University of KentuckyFollow
Fanmuyi Yang, University of KentuckyFollow
Guoying Zhang, University of KentuckyFollow
Susan S. Smyth, University of KentuckyFollow
Zhenyu Li, University of KentuckyFollow
Yoshimi Takai, Kobe University, Japan
Sidney W. Whiteheart, University of KentuckyFollow

Abstract

Genome-wide association studies (GWAS) have linked genes encoding several soluble NSF attachment protein receptor (SNARE) regulators to cardiovascular disease risk factors. Because these regulatory proteins may directly affect platelet secretion, we used SNARE-containing complexes to affinity purify potential regulators from human platelet extracts. Syntaxin-binding protein 5 (STXBP5; also known as tomosyn-1) was identified by mass spectrometry, and its expression in isolated platelets was confirmed by RT-PCR analysis. Coimmunoprecipitation studies showed that STXBP5 interacts with core secretion machinery complexes, such as syntaxin-11/SNAP23 heterodimers, and fractionation studies suggested that STXBP5 also interacts with the platelet cytoskeleton. Platelets from Stxbp5 KO mice had normal expression of other key secretory components; however, stimulation-dependent secretion from each of the 3 granule types was markedly defective. Secretion defects in STXBP5-deficient platelets were confirmed via lumi-aggregometry and FACS analysis for P-selectin and LAMP-1 exposure. Interestingly, STXBP5-deficient platelets had altered granule cargo levels, despite having normal morphology and granule numbers. Consistent with secretion and cargo deficiencies, Stxbp5 KO mice showed dramatic bleeding in the tail transection model and defective hemostasis in the FeCl3-induced carotid injury model. Transplantation experiments indicated that these defects were due to loss of STXBP5 in BM-derived cells. Our data demonstrate that STXBP5 is required for normal arterial hemostasis, due to its contributions to platelet granule cargo packaging and secretion.

Document Type

Article

Publication Date

10-1-2014

Notes/Citation Information

Published in The Journal of Clinical Investigation, v. 124, no. 10, p. 4517-4528.

The copyright holder has granted the permission for posting the article here.

Digital Object Identifier (DOI)

http://dx.doi.org/10.1172/JCI75572

Repository Citation

Ye, Shaojing; Huang, Yunjie; Joshi, Smita; Zhang, Jinchao; Yang, Fanmuyi; Zhang, Guoying; Smyth, Susan S.; Li, Zhenyu; Takai, Yoshimi; and Whiteheart, Sidney W., "Platelet Secretion and Hemostasis Require Syntaxin-binding Protein STXBP5" (2014). Molecular and Cellular Biochemistry Faculty Publications. 40.
https://uknowledge.uky.edu/biochem_facpub/40