Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada.
EMBO Rep. 2017 Dec;18(12):2119-2130. doi: 10.15252/embr.201744034. Epub 2017 Oct 13.
Epidermal growth factor (EGF) activates the EGF receptor (EGFR) and stimulates its internalization and trafficking to lysosomes for degradation. However, a percentage of EGFR undergoes ligand-independent endocytosis and is rapidly recycled back to the plasma membrane. Importantly, alterations in EGFR recycling are a common hallmark of cancer, and yet, our understanding of the machineries controlling the fate of endocytosed EGFR is incomplete. Intersectin-s is a multi-domain adaptor protein that is required for internalization of EGFR Here, we discover that intersectin-s binds DENND2B, a guanine nucleotide exchange factor for the exocytic GTPase Rab13, and this interaction promotes recycling of ligand-free EGFR to the cell surface. Intriguingly, upon EGF treatment, DENND2B is phosphorylated by protein kinase D and dissociates from intersectin-s, allowing for receptor targeting to degradation. Our study thus reveals a novel mechanism controlling the fate of internalized EGFR with important implications for cancer.
表皮生长因子 (EGF) 激活表皮生长因子受体 (EGFR),并刺激其内化和转运到溶酶体进行降解。然而,一定比例的 EGFR 会发生配体非依赖性内吞作用,并迅速被重新循环回质膜。重要的是,EGFR 循环的改变是癌症的一个常见特征,但我们对控制内化 EGFR 命运的机制的理解还不完整。衔接蛋白-s 是一种多功能衔接蛋白,是 EGFR 内化所必需的。在这里,我们发现衔接蛋白-s 与 DENND2B 结合,DENND2B 是外向 GTPase Rab13 的鸟嘌呤核苷酸交换因子,这种相互作用促进了无配体 EGFR 的循环回到质膜。有趣的是,在 EGF 处理后,蛋白激酶 D 使 DENND2B 磷酸化并从衔接蛋白-s 上解离,从而使受体靶向降解。我们的研究因此揭示了一种控制内化 EGFR 命运的新机制,对癌症具有重要意义。