Molecular mechanisms of platelet exocytosis: role of SNAP-23 and syntaxin 2 in dense core granule release
Molecular mechanisms of platelet exocytosis: role of SNAP-23 and syntaxin 2 in dense core granule release
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DOI：
10.1182/blood.v95.3.921.003k17_921_929
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发表时间：
2000-02-01
期刊：
影响因子：
20.3
通讯作者：
Whiteheart, SW
中科院分区：
文献类型：
--
作者：
Chen, D;Bernstein, AM;Whiteheart, SW
为了表征血小板分泌的分子机制，我们着重于钙诱导的致密核心颗粒的胞吐作用。血小板含有几种已知的t-SNARE（可溶性N-乙基马来酰亚胺敏感因子[NSF]附着蛋白受体），如突触融合蛋白2、4和7以及SNAP-23（突触体相关蛋白23）。通过使用体外胞吐试验，我们已经能够分配的角色，这些t-SNARE在致密的核心颗粒释放。这种钙诱导的分泌依赖于SNARE蛋白，因为它被添加重组α-SNAP刺激，并被显性负性α-SNAP-L294 A突变体或抗α-SNAP和抗NSF抗体抑制。SNAP-23抗体和抑制性C-末端SNAP-23肽均阻断致密核心颗粒释放，证明了SNAP-23的作用。与其他细胞类型不同，血小板含有大量可溶性SNAP-23，其不分配到Triton X-114中。在测试的抗突触融合蛋白抗体中，仅抗突触融合蛋白2抗体抑制致密核心颗粒释放。免疫沉淀研究表明，2 t-SNARE syntaxin 2和SNAP-23在体内确实形成复合物。这些数据清楚地表明，SNAPs，NSF，和特定的t-SNARE用于致密核心颗粒的释放，这些数据提供了一个更好的理解调节胞吐血小板。(C)2000年，美国血液学会。
To characterize the molecular mechanisms of platelet secretion, we focused on the calcium-induced exocytosis of dense core granules. Platelets contain several known t-SNAREs (soluble N-ethylmaleimide sensitive factor [NSF] attachment protein receptors) such as syntaxins 2, 4, and 7 and SNAP-23 (synaptosomal associated protein 23). By using an in vitro exocytosis assay, we have been able to assign roles for some of these t-SNAREs in dense core granule release. This calcium-induced secretion relies on the SNARE proteins because it is stimulated by the addition of recombinant alpha-SNAP and inhibited by a dominant negative alpha-SNAP-L294A mutant or by anti-alpha-SNAP and anti-NSF antibodies. SNAP-23 antibodies and an inhibitory C-terminal SNAP-23 peptide both blocked dense core granule release, demonstrating a role for SNAP-23. Unlike other cell types, platelets contain a significant pool of soluble SNAP-23, which does not partition into Triton X-114. Of the anti-syntaxin antibodies tested, only anti-syntaxin 2 antibody inhibited dense core granule release. Immunoprecipitation studies showed that the 2 t-SNAREs syntaxin 2 and SNAP-23 do form a complex in vivo. These data clearly show that SNAPs, NSF, and specific t-SNAREs are used for dense core granule release; these data provide a greater understanding of regulated exocytosis in platelets.(C) 2000 by The American Society of Hematology.