Zhang Weilin, Zhao Lili, Liu Jun, Du Juan, Yan Rong, Dai Kesheng
School of Biological Science and Medical Engineering, Beijing University of Aeronautics and Astronautics, 37 Xueyuan Road, Haidian district, Beijing 100083, China.
Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, Suzhou 215007, China.
Int J Mol Sci. 2012;13(5):5364-5374. doi: 10.3390/ijms13055364. Epub 2012 May 2.
The interaction of platelet glycoprotein (GP) Ib-IX with von Willebrand factor (VWF) exposed at the injured vessel wall or atherosclerotic plaque rupture initiates platelet transient adhesion to the injured vessel wall, which triggers intracellular signaling cascades leading to platelet activation and thrombus formation. 14-3-3ζ has been verified to regulate the VWF binding function of GPIb-IX by interacting with the cytoplasmic domains of GPIb-IX. However, the data regarding the role of 14-3-3ζ in GPIb-IX-VWF interaction-induced signaling still remain controversial. In the present study, the data indicate that the S609A mutation replacing Ser(609) of GPIbα with alanine (S609A) significantly prevented the association of 14-3-3ζ with GPIbα before and after the VWF binding to GPIbα. GPIb-IX-VWF interaction-induced activations of Src family kinases and protein kinase C were clearly reduced in S609A mutation. Furthermore, S609A mutation significantly inhibited GPIb-IX-VWF interaction-induced elevation of cytoplasmic Ca(2+) levels in flow cytometry analysis. Taken together, these data indicate that the association of 14-3-3ζ with the cytoplasmic domain of GPIbα plays an important role in GPIb-IX-VWF interaction-induced signaling.
血小板糖蛋白（GP）Ib-IX与暴露于受损血管壁或动脉粥样硬化斑块破裂处的血管性血友病因子（VWF）相互作用，引发血小板与受损血管壁的短暂黏附，这会触发细胞内信号级联反应，导致血小板活化和血栓形成。14-3-3ζ已被证实可通过与GPIb-IX的细胞质结构域相互作用来调节GPIb-IX的VWF结合功能。然而，关于14-3-3ζ在GPIb-IX-VWF相互作用诱导的信号传导中作用的数据仍存在争议。在本研究中，数据表明，用丙氨酸取代GPIbα的Ser(609)的S609A突变（S609A）在VWF与GPIbα结合之前和之后均显著阻止了14-3-3ζ与GPIbα的结合。在S609A突变中，GPIb-IX-VWF相互作用诱导的Src家族激酶和蛋白激酶C的活化明显降低。此外，在流式细胞术分析中，S609A突变显著抑制了GPIb-IX-VWF相互作用诱导的细胞质Ca(2+)水平升高。综上所述，这些数据表明14-3-3ζ与GPIbα细胞质结构域的结合在GPIb-IX-VWF相互作用诱导的信号传导中起重要作用。
