The clathrin adaptor complex-1 and Rab12 regulate post-golgi trafficking of WT epidermal growth factor receptor (EGFR).

The epidermal growth factor receptor (EGFR) plays important roles in cancer progression and is one of the major drug targets for targeted cancer therapy. Although fundamentally important, how newly synthesized EGFR is delivered to the cell surface to perform its cellular functions remains to be further investigated. In this study, we found using the approaches of gene knockout, siRNA knockdown, streptavidin pull-down, and co-immunoprecipitation assays that the clathrin adaptor complex-1 (AP-1) and Rab12 interact with EGFR and regulate the export of EGFR out of the trans-Golgi network (TGN). In addition, the tyrosine residue at the 998 position on human EGFR is critical to bind to AP-1, and this residue is important for TGN export of EGFR. We demonstrate that AP-1 and Rab12 are important for epidermal growth factor–induced phosphorylation of EGFR, cell elongation, and proliferation, suggesting that AP-1–mediated and Rab12-mediated post-Golgi trafficking is important for EGFR signaling. Moreover, TGN export of the constitutively activated mutant form of EGFR (EGFRL858R) is independent of AP-1 and Rab12. Our results reveal insights into the molecular mechanisms that mediate the TGN-to-cell surface delivery of EGFR and indicate that TGN export of WT EGFR and EGFRL858R depends on different cellular factors.

表皮生长因子受体（EGFR）在癌症进展中起重要作用，是癌症靶向治疗的主要药物靶点之一。尽管至关重要，但新合成的EGFR如何被运送到细胞表面以发挥其细胞功能仍有待进一步研究。在本研究中，我们通过基因敲除、小干扰RNA敲低、链霉亲和素下拉以及免疫共沉淀分析等方法发现，网格蛋白衔接蛋白复合物 - 1（AP - 1）和Rab12与EGFR相互作用，并调节EGFR从反面高尔基体管网状结构（TGN）的输出。此外，人EGFR上第998位的酪氨酸残基对于与AP - 1结合至关重要，且该残基对EGFR从TGN的输出很重要。我们证明AP - 1和Rab12对表皮生长因子诱导的EGFR磷酸化、细胞伸长和增殖很重要，这表明AP - 1介导的和Rab12介导的高尔基体后运输对EGFR信号传导很重要。此外，组成型激活的EGFR突变体形式（EGFRL858R）从TGN的输出不依赖于AP - 1和Rab12。我们的研究结果揭示了介导EGFR从TGN到细胞表面运输的分子机制，并表明野生型EGFR和EGFRL858R从TGN的输出依赖于不同的细胞因子。