L-selectin activates the Ras pathway via the tyrosine kinase p56(lck)
L-selectin activates the Ras pathway via the tyrosine kinase p56(lck)
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DOI：
10.1073/pnas.93.26.15376
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发表时间：
1996-12-24
影响因子：
11.1
通讯作者：
Lang, F
中科院分区：
文献类型：
--
作者：
Brenner, B;Gulbins, E;Lang, F
选择素调节RAILING，这是白细胞与内皮细胞黏附的初始步骤[Springer，T.A.(1995)Annu.菲西奥尔牧师。57,827-872和Butcher，E.C.(1991)Cell 67,1033-1036]。在这项研究中，我们发现L-选择素用不同的抗体或糖模拟物触发Jurkat细胞，导致src-酪氨酸激酶p56(Lck)的激活，细胞内蛋白的酪氨酸磷酸化，特别是丝裂原激活蛋白激酶和L-选择素，以及Grb2/SOS与L-选择素的结合。这种关联与p21Ras、丝裂原激活蛋白激酶、rac2的激活以及O-2(-)合成的一过性增加有关。L-选择素对RAS通路的刺激需要功能性p56(Lck)，因为p56(Lck)缺陷的Jurkat细胞(JCaM1.6)不显示酪氨酸磷酸化，L-选择素与Grb2/SOS结合，以及在L-选择素触发时RAS的激活。将p56(Lck)基因导入JCaM1.6细胞，重现了观察到的信号转导事件。Ras和rac2的基因抑制分别阻止了rac2的刺激和O-2(-)的合成。通过刺激L-选择素-P815、L-选择素阳性的细胞间质或外周血淋巴细胞引起与Jurkat细胞相同的激活事件，表明了观察到的信号级联反应的特异性和生理意义。我们的结果描绘了一个从L-选择素通过p56(Lck)、Grb2/sOS、RAS和rac2到O-2(-)的信号级联。
Selectins mediate railing, the initial step of leukocyte adhesion to endothelial cells [Springer, T. A. (1995) Annu. Rev. Physiol. 57, 827-872 and Butcher, E. C. (1991) Cell 67, 1033-1036]. In this study we show that L-selectin triggering of Jurkat cells using different antibodies or glycomimetics resulted in activation of the src-tyrosine kinase p56(lck); tyrosine phosphorylation of intracellular proteins, in particular mitogen activating protein kinase and L-selectin; and association of Grb2/Sos with L-selectin. This association correlated with an activation of p21Ras, mitogen-activating protein kinase, Rac2, and a transient increase of O-2(-) synthesis. Stimulation of the Ras pathway by L-selectin requires functional p56(lck), since p56(lck)-deficient Jurkat cells (JCaM1.6) do not show tyrosine phosphorylation, association of L-selectin with Grb2/Sos, and activation of Ras upon L-selectin triggering. Transfection of JCaM1.6 cells with p56(lck) reconstitutes the observed signaling events. Genetic inhibition of Ras or Rac2 prevented Rac2 stimulation and O-2(-) synthesis, respectively. The specificity and the physiological significance of the observed signaling cascade is indicated by stimulation of L-selectin-transfected P815, L-selectin-positive CEM or peripheral blood lymphocytes resulting in the same activation events as in Jurkat cells. Our results paint to a signaling cascade from L-selectin via p56(lck), Grb2/Sos, Ras, and Rac2 to O-2(-).