Collagen induces tyrosine phosphorylation of Wiskott-Aldrich syndrome protein in human platelets
Collagen induces tyrosine phosphorylation of Wiskott-Aldrich syndrome protein in human platelets
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DOI：
10.1182/blood.v92.6.1852.418k36_1852_1858
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发表时间：
1998-09-15
期刊：
影响因子：
20.3
通讯作者：
Ikeda, Y
中科院分区：
文献类型：
--
作者：
Oda, A;Ochs, HD;Ikeda, Y
Wiskott-Aldrich综合征（WAS）和X连锁血小板减少症（XLT）是由WAS蛋白（WASP）基因突变引起的。所有造血干细胞来源的谱系，包括血小板，表达WASP。WAS患者的血小板比正常人的血小板小，血小板聚集和肌动蛋白聚合的缺陷已被报道。为了确定WASP对正常血小板功能是否重要，我们研究了它在信号转导中的作用。我们发现，胶原蛋白而不是血小板生成素或凝血酶诱导血小板相关WASP的酪氨酸磷酸化快速而强烈的增加。胶原诱导的WASP酪氨酸磷酸化被细胞松弛素D和渥曼青霉素抑制。这表明肌动蛋白聚合和磷脂酰肌醇3-激酶（Pla-kinase）在WASP的酪氨酸磷酸化诱导中起作用。谷胱甘肽S-转移酶（GST）Grb 2的结合WASP中看到静息血小板裂解物。当胶原刺激的血小板裂解物与GST-Grb 2孵育时，结合减少，表明WASP的酪氨酸磷酸化可能直接或间接调节WASP的适配器功能。尽管凝血酶和促血小板生成素诱导的WASP酪氨酸磷酸化的增加可以忽略不计或微不足道，但凝血酶活化血小板的WASP以聚集依赖性方式掺入Triton X-100不溶性10，000 g可沉淀残留物中，表明其可能在血小板聚集期间的细胞骨架过程中具有调节作用。最后。我们发现WASP响应于钙蛋白酶的激活而被切割，钙蛋白酶是一种可能在聚集后信号传导过程中起作用的蛋白酶。我们的数据表明，胶原蛋白特异性地诱导WASP的酪氨酸磷酸化的增加，并且WASP在凝血酶诱导的聚集过程中通过其重新分布到细胞骨架及其在聚集过程中的裂解参与信号传导。(C)1998年，美国血液学会。
Wiskott-Aldrich syndrome (WAS) and X-linked thrombocytopenia (XLT) are caused by mutations of the WAS protein (WASP) gene. All hematopoietic stem cell-derived lineages, including platelets, express WASP. Platelets from WAS patients are smaller than their normal counterparts and defects in platelet aggregation and actin polymerization have been reported. To determine if WASP is important for normal platelet function, we examined its role in signal transduction. We found that collagen but not thrombopoietin or thrombin induces a rapid and robust increase in tyrosine phosphorylation of platelet-associated WASP. Collagen-induced tyrosine phosphorylation of WASP was inhibited by cytochalasin D and wortmannin. respectively, suggesting that actin polymerization and phosphatidylinositol 3-kinase (Pla-kinase) play a role in the induction of tyrosine phosphorylation of WASP. Binding of glutathion S-transferase (GST)Grb2 to WASP was seen in the lysate of resting platelets. The binding was reduced when lysates from collagen-stimulated platelets were incubated with GST-Grb2, suggesting that tyrosine phosphorylation of WASP may directly or indirectly modulate the adapter function of WASP. Although thrombin- and thrombopoietin-induced increase in tyrosine phosphorylation of WASP is negligible or marginal, WASP from thrombin-activated platelets became incorporated into the Triton X-100-insoluble 10,000g sedimentable residue in an aggregation-dependent manner, suggesting that it may have a regulatory role in platelet cytoskeletal processes during aggregation. Lastly. we found that WASP is cleaved in response to activation of calpain, a protease that may have a role in postaggregation signaling processes. Our data suggest that collagen specifically induces an increase in tyrosine phosphorylation of WASP and that WASP is involved in signaling during thrombin-induced aggregation by its redistribution to the cytoskeleton and its cleavage during aggregation. (C) 1998 by The American Society of Hematology.