Single‐molecule analysis of epidermal growth factor binding on the surface of living cells
Single‐molecule analysis of epidermal growth factor binding on the surface of living cells
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DOI：
10.1038/sj.emboj.7601308
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发表时间：
2006-09
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影响因子：
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通讯作者：
Y. Teramura;J. Ichinose;H. Takagi;K. Nishida;T. Yanagida;Y. Sako
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文献类型：
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作者：
Y. Teramura;J. Ichinose;H. Takagi;K. Nishida;T. Yanagida;Y. Sako
表皮生长因子受体（EGFR）诱导的细胞反应在单个细胞表面的数万个EGFR分子中的占有率小于1%时立即发生。EGFR的活化需要形成与每个分子的单个配体结合的EGFR的信号传导二聚体。如何在如此低的占有率下形成足够数量的信号二聚体仍然是未知的。在这里，我们使用单分子成像和数学建模分析了EGF结合的动力学和信号二聚体的形成。细胞表面的少量EGFR形成二聚体结合位点，其结合EGF的速度比单体结合位点快两个数量级。有一个积极的合作结合EGF的二聚体结合位点，通过一个新发现的动力学中间体。这两种机制促进EGF/EGFR复合物的信号传导二聚体的形成。
Global cellular responses induced by epidermal growth factor (EGF) receptor (EGFR) occur immediately with a less than 1% occupancy among tens of thousands of EGFR molecules on single cell surface. Activation of EGFR requires the formation of a signaling dimer of EGFR bound with a single ligand to each molecule. How sufficient numbers of signaling dimers are formed at such low occupancy rate is still not known. Here, we have analyzed the kinetics of EGF binding and the formation of the signaling dimer using single‐molecule imaging and mathematical modeling. A small number of EGFR on the cell surface formed dimeric binding sites, which bound EGF two orders of magnitude faster than the monomeric binding sites. There was a positive cooperative binding of EGF to the dimeric binding sites through a newly discovered kinetic intermediate. These two mechanisms facilitate the formation of signaling dimers of EGF/EGFR complexes.