RGT, a synthetic peptide corresponding to the integrin β3 cytoplasmic C-terminal sequence, selectively inhibits outside-in signaling in human platelets by disrupting the interaction of integrin αIIbβ3 with Src kinase
RGT, a synthetic peptide corresponding to the integrin β3 cytoplasmic C-terminal sequence, selectively inhibits outside-in signaling in human platelets by disrupting the interaction of integrin αIIbβ3 with Src kinase
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DOI：
10.1182/blood-2007-09-110437
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发表时间：
2008-08-01
期刊：
影响因子：
20.3
通讯作者：
Xi, Xiaodong
中科院分区：
文献类型：
--
作者：
Su, Xiaoyu;Mi, Jianqing;Xi, Xiaodong
突变分析已经确定整联蛋白β 3亚基的胞质尾区结合c-Src（在本研究中称为Src），并且对于双向整联蛋白信号传导至关重要。在这里，我们表明在洗涤的人血小板中，对应于整合素β 3 C-末端序列的细胞可渗透的肉豆蔻酰化RGT肽（myr-RGT）剂量依赖性地抑制稳定的血小板粘附和在固定的纤维蛋白原上的扩散，以及纤维蛋白凝块收缩。Myr-RGT还抑制聚集依赖性血小板分泌和分泌依赖性血小板聚集的二磷酸腺苷，利托那韦，或凝血酶诱导的第二波。因此，myr-RGT抑制整联蛋白由外向内信号传导。相反，myr-RGT对腺苷二磷酸诱导的可溶性纤维蛋白原与血小板的结合没有抑制作用，这依赖于整联蛋白由内而外的信号传导。此外，RGT肽诱导Src从整合素β 3解离，并剂量依赖性地抑制纯化的重组β 3胞质结构域与Src-SH 3的结合。此外，myr-RGT抑制β 3细胞质酪氨酸Y-747和Y-759的磷酸化。这些数据表明β 3-Src相互作用在由外向内信号传导中的重要作用。因此，在完整的人血小板中，myr-RGT破坏Src与β 3的结合和选择性阻断整联蛋白α IIb β 3由外向内的信号传导提示了一种潜在的新的抗血栓形成策略。
Mutational analysis has established that the cytoplasmic tail of the integrin beta 3 subunit binds c-Src (termed as Src in this study) and is critical for bidirectional integrin signaling. Here we show in washed human platelets that a cell-permeable, myristoylated RGT peptide (myr-RGT) corresponding to the integrin beta 3 C-terminal sequence dose-dependently inhibited stable platelet adhesion and spreading on immobilized fibrinogen, and fibrin clot retraction as well. Myr-RGT also inhibited the aggregation-dependent plate-let secretion and secretion-dependent second wave of platelet aggregation induced by adenosine diphosphate, ristocetin, or thrombin. Thus, myr-RGT inhibited integrin outside-in signaling. In contrast, myr-RGT had no inhibitory effect on adenosine diphosphate-induced soluble fibrinogen binding to platelets that is dependent on integrin inside-out signaling. Furthermore, the RGT peptide induced dissociation of Src from integrin beta 3 and dose-dependently inhibited the purified recombinant beta 3 cytoplasmic domain binding to Src-SH3. In addition, phosphorylation of the beta 3 cytoplasmic tyrosines, Y-747 and Y-759, was inhibited by myr-RGT These data indicate an important role for beta 3-Src interaction in outside-in signaling. Thus, in intact human platelets, disruption of the association of Src with beta 3 and selective blockade of integrin alpha llb beta 3 outside-in signaling by myr-RGT suggest a potential new antithrombotic strategy.