Roles of integrin β3 cytoplasmic tail in bidirectional signal transduction in a trans-dominant inhibition model
Roles of integrin β3 cytoplasmic tail in bidirectional signal transduction in a trans-dominant inhibition model
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DOI：
10.1007/s11684-016-0460-0
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发表时间：
2016-08
影响因子：
8.1
通讯作者：
Jian-song Huang;Yu-lan Zhou;Xiao-yu Su;Yuanjing Lyu;Lanlan Tao;Xiaofeng Shi;Ping Liu;Zhangbiao Long;Z. Ruan;Bing Xiao;Wenda Xi;Quansheng Zhou;J. Mao;X. Xi
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文献类型：
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作者：
Jian-song Huang;Yu-lan Zhou;Xiao-yu Su;Yuanjing Lyu;Lanlan Tao;Xiaofeng Shi;Ping Liu;Zhangbiao Long;Z. Ruan;Bing Xiao;Wenda Xi;Quansheng Zhou;J. Mao;X. Xi
我们利用反显性抑制模型评估了整合素β3细胞质尾部calpain切割相关突变在整合素α ib β3双向信号通路中的作用。由人IL-2受体（Tac）胞外和跨膜结构域和人整合素β3细胞质结构域组成的嵌合Tac-β3蛋白（即Tac-β3、Tac-β3Δ741、Tac-β3Δ747、Tac-β3Δ754、Tac-β3Δ759和Tac-β3ΔNITY）在含有人糖蛋白Ib-IX和野生型整合素αIIbβ3的123个CHO细胞中稳定表达。测定不同细胞在固定纤维蛋白原上的稳定粘附和扩散，以及与可溶性纤维蛋白原的结合，分别代表由外向内和由内向外的信号事件。嵌合蛋白Tac-β3抑制和Tac-β3ΔNITY部分减弱稳定粘附和扩散。Tac-β3、Tac-β3Δ759、Tac-β3ΔNITY和Tac-β3Δ754破坏可溶性纤维蛋白原结合，但Tac-β3Δ747和Tac-β3Δ741不破坏可溶性纤维蛋白原结合。结果表明，Tac-β3和Tac-β3ΔNITY显著抑制了双向信号传导，但抑制程度较轻。此外，123/Tac-β3Δ759和123/Tac-β3Δ754细胞中只有内向外信号通路受损，而123/Tac-β3Δ747和123/Tac-β3Δ741细胞中双向信号通路完整。综上所述，整合素β3的calpain切割通过中断其与细胞质蛋白的相互作用而不是改变其构象，从而对信号传导产生调节作用，从而可能调节血小板功能。
We evaluated the roles of calpain cleavage-related mutations of the integrin β3 cytoplasmic tail in integrin αIIbβ3 bidirectional signaling using a trans-dominant inhibition model. Chimeric Tac-β3 proteins (i.e., Tac-β3, Tac-β3Δ741, Tac-β3Δ747, Tac-β3Δ754, Tac-β3Δ759, and Tac-β3ΔNITY) consisting of the extracellular and transmembrane domains of human IL-2 receptor (Tac) and the human integrin β3 cytoplasmic domain were stably expressed in the 123 CHO cells harboring human glycoprotein Ib-IX and wild-type integrin αIIbβ3. The different cells were assayed for stable adhesion and spreading on immobilized fibrinogen, and for binding soluble fibrinogen representing outside-in and inside-out signaling events, respectively. The chimeric protein Tac-β3 inhibited, and Tac-β3ΔNITY partially attenuated stable adhesion and spreading. Tac-β3, Tac-β3Δ759, Tac-β3ΔNITY, and Tac-β3Δ754, but not Tac-β3Δ747 or Tac-β3Δ741, impaired the soluble fibrinogen binding. Results indicated that the bidirectional signaling was significantly inhibited by Tac-β3 and Tac-β3ΔNITY, albeit to a much lesser extent. Moreover, only inside-out signaling was impaired in the 123/Tac-β3Δ759 and 123/Tac-β3Δ754 cells in contrast to an intact bidirectional signaling in the 123/Tac-β3Δ747 and 123/Tac-β3Δ741 cells. In conclusion, the calpain cleavage of integrin β3 resulted in the regulatory effects on signaling by interrupting its interaction with cytoplasmic proteins rather than altering its conformation, and may thus regulate platelet function.