NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21701, USA.
Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA.
Cell Rep. 2020 Jul 21;32(3):107909. doi: 10.1016/j.celrep.2020.107909.
Sprouty-related, EVH1 domain-containing (SPRED) proteins negatively regulate RAS/mitogen-activated protein kinase (MAPK) signaling following growth factor stimulation. This inhibition of RAS is thought to occur primarily through SPRED1 binding and recruitment of neurofibromin, a RasGAP, to the plasma membrane. Here, we report the structure of neurofibromin (GTPase-activating protein [GAP]-related domain) complexed with SPRED1 (EVH1 domain) and KRAS. The structure provides insight into how the membrane targeting of neurofibromin by SPRED1 allows simultaneous interaction with activated KRAS. SPRED1 and NF1 loss-of-function mutations occur across multiple cancer types and developmental diseases. Analysis of the neurofibromin-SPRED1 interface provides a rationale for mutations observed in Legius syndrome and suggests why SPRED1 can bind to neurofibromin but no other RasGAPs. We show that oncogenic EGFR(L858R) signaling leads to the phosphorylation of SPRED1 on serine 105, disrupting the SPRED1-neurofibromin complex. The structural, biochemical, and biological results provide new mechanistic insights about how SPRED1 interacts with neurofibromin and regulates active KRAS levels in normal and pathologic conditions.
sprouty 相关、EVH1 结构域包含蛋白（SPRED）在生长因子刺激后负向调节 RAS/丝裂原活化蛋白激酶（MAPK）信号通路。这种对 RAS 的抑制作用被认为主要是通过 SPRED1 与 RasGAP 神经纤维瘤蛋白的结合和募集到质膜来实现的。在这里，我们报告了神经纤维瘤蛋白（GTP 酶激活蛋白 [GAP] 相关结构域）与 SPRED1（EVH1 结构域）和 KRAS 复合物的结构。该结构提供了关于 SPRED1 通过质膜靶向神经纤维瘤蛋白如何允许与激活的 KRAS 同时相互作用的见解。SPRED1 和 NF1 功能丧失突变发生在多种癌症类型和发育性疾病中。对神经纤维瘤蛋白-SPRED1 界面的分析为 Legius 综合征中观察到的突变提供了依据，并解释了为什么 SPRED1 可以与神经纤维瘤蛋白结合，但不能与其他 RasGAP 结合。我们表明，致癌的 EGFR（L858R）信号导致丝氨酸 105 上的 SPRED1 磷酸化，破坏了 SPRED1-神经纤维瘤蛋白复合物。结构、生化和生物学结果为 SPRED1 如何与神经纤维瘤蛋白相互作用以及在正常和病理条件下调节活性 KRAS 水平提供了新的机制见解。
