Ibach Jenny, Radon Yvonne, Gelléri Márton, Sonntag Michael H, Brunsveld Luc, Bastiaens Philippe I H, Verveer Peter J
Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
Laboratory of Chemical Biology, Department of Biomedical Engineering, and Institute of Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands.
PLoS One. 2015 Nov 17;10(11):e0143162. doi: 10.1371/journal.pone.0143162. eCollection 2015.
Signaling from the epidermal growth factor receptor (EGFR) via phosphorylation on its C-terminal tyrosine residues requires self-association, which depends on the diffusional properties of the receptor and its density in the plasma membrane. Dimerization is a key event for EGFR activation, but the role of higher order clustering is unknown. We employed single particle tracking to relate the mobility and aggregation of EGFR to its signaling activity. EGFR mobility alternates between short-lived free, confined and immobile states. In the immobile state, EGFR tends to aggregate in clathrin-coated pits, which is further enhanced in a phosphorylation-dependent manner and does not require ligand binding. EGFR phosphorylation is further amplified by cross-phosphorylation in clathrin-coated pits. Because phosphorylated receptors can escape from the pits, local gradients of signaling active EGFR are formed. These results show that amplification of EGFR phosphorylation by receptor clustering in clathrin-coated pits supports signal activation at the plasma membrane.
表皮生长因子受体（EGFR）通过其C末端酪氨酸残基的磷酸化进行信号传导需要自身缔合，这取决于受体的扩散特性及其在质膜中的密度。二聚化是EGFR激活的关键事件，但高阶聚集的作用尚不清楚。我们采用单粒子追踪来关联EGFR的流动性和聚集与其信号传导活性。EGFR的流动性在短暂的自由、受限和固定状态之间交替。在固定状态下，EGFR倾向于聚集在网格蛋白包被小窝中，这以磷酸化依赖的方式进一步增强，并且不需要配体结合。EGFR磷酸化通过网格蛋白包被小窝中的交叉磷酸化进一步放大。由于磷酸化的受体可以从小窝中逸出，因此形成了信号活性EGFR的局部梯度。这些结果表明，网格蛋白包被小窝中受体聚集对EGFR磷酸化的放大支持了质膜处的信号激活。
