Integrin α5 Suppresses the Phosphorylation of Epidermal Growth Factor Receptor and Its Cellular Signaling of Cell Proliferation via N-Glycosylation
Integrin α5 Suppresses the Phosphorylation of Epidermal Growth Factor Receptor and Its Cellular Signaling of Cell Proliferation via N-Glycosylation
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DOI：
10.1074/jbc.m115.682229
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发表时间：
2015-12-04
影响因子：
4.8
通讯作者：
Gu, Jianguo
中科院分区：
文献类型：
--
作者：
Hang, Qinglei;Isaji, Tomoya;Gu, Jianguo
整合素α 5 β 1介导的细胞粘附调节多种细胞反应，包括细胞增殖、存活和不同细胞信号传导途径之间的串扰。已知整联蛋白α 5 β 1传递允许信号，使锚定依赖性受体酪氨酸激酶信号传导成为可能。然而，整合素α 5 β 1对细胞增殖的影响存在争议，整合素α 5 β 1与受体酪氨酸激酶之间调节所涉及的分子机制仍不清楚。在这里，我们表明，整合素α 5功能作为一个负调节表皮生长因子受体（EGFR）信号通过其N-糖基化。WT整合素α 5的表达抑制EGFR磷酸化和EGF刺激后的内化。然而，含有较少N-聚糖的N-糖基化突变体整合素α 5，S3-5的表达逆转了EGFR介导的信号传导和细胞增殖的抑制。WT而非S3-5整联蛋白α 5以机械方式与低密度脂筏中的EGFR和糖脂形成复合物，并且复合物形成在EGF刺激后被破坏，表明整联蛋白α 5的N-糖基化通过促进整联蛋白α 5-糖脂-EGFR复合物形成来抑制EGFR活化。此外，整合素α 5的Calf-1，2结构域上的那些N-聚糖的一致恢复恢复了抑制作用以及与EGFR的复合物形成。综上所述，这些数据首次证明EGFR活化可以通过整联蛋白α 5的N-糖基化来调节，这是整联蛋白和生长因子受体之间串扰的新分子范例。
Integrin alpha 5 beta 1-mediated cell adhesion regulates a multitude of cellular responses, including cell proliferation, survival, and cross-talk between different cellular signaling pathways. Integrin alpha 5 beta 1 is known to convey permissive signals enabling anchorage-dependent receptor tyrosine kinase signaling. However, the effects of integrin alpha 5 beta 1 on cell proliferation are controversial, and the molecular mechanisms involved in the regulation between integrin alpha 5 beta 1 and receptor tyrosine kinase remain largely unclear. Here we show that integrin alpha 5 functions as a negative regulator of epidermal growth factor receptor (EGFR) signaling through its N-glycosylation. Expression of WT integrin alpha 5 suppresses the EGFR phosphorylation and internalization upon EGF stimulation. However, expression of the N-glycosylation mutant integrin alpha 5, S3-5, which contains fewer N-glycans, reversed the suppression of the EGFR-mediated signaling and cell proliferation. In a mechanistic manner, WT but not S3-5 integrin alpha 5 forms a complex with EGFR and glycolipids in the low density lipid rafts, and the complex formation is disrupted upon EGF stimulation, suggesting that the N-glycosylation of integrin alpha 5 suppresses the EGFR activation through promotion of the integrin alpha 5-glycolipids-EGFR complex formation. Furthermore, consistent restoration of those N-glycans on the Calf-1,2 domain of integrin alpha 5 reinstated the inhibitory effects as well as the complex formation with EGFR. Taken together, these data are the first to demonstrate that EGFR activation can be regulated by the N-glycosylation of integrin alpha 5, which is a novel molecular paradigm for the cross-talk between integrins and growth factor receptors.