Parker Matthew W, Linkugel Andrew D, Goel Hira Lal, Wu Tingting, Mercurio Arthur M, Vander Kooi Craig W
Department of Molecular and Cellular Biochemistry, Center for Structural Biology, University of Kentucky, Lexington, KY 40536, USA.
Department of Molecular and Cellular Biochemistry, Center for Structural Biology, University of Kentucky, Lexington, KY 40536, USA; Washington University School of Medicine, St. Louis, MO 63110, USA.
Structure. 2015 Apr 7;23(4):677-87. doi: 10.1016/j.str.2015.01.018. Epub 2015 Mar 5.
Vascular endothelial growth factor C (VEGF-C) is a potent lymphangiogenic cytokine that signals via the coordinated action of two cell surface receptors, Neuropilin-2 (Nrp2) and VEGFR-3. Diseases associated with both loss and gain of VEGF-C function, lymphedema and cancer, respectively, motivate studies of VEGF-C/Nrp2 binding and inhibition. Here, we demonstrate that VEGF-C binding to Nrp2 is regulated by C-terminal proteolytic maturation. The structure of the VEGF-C C terminus in complex with the ligand binding domains of Nrp2 demonstrates that a cryptic Nrp2 binding motif is released upon proteolysis, allowing specific engagement with the b1 domain of Nrp2. Based on the identified structural requirements for Nrp2 binding to VEGF-C, we hypothesized that the endogenous secreted splice form of Nrp2, s9Nrp2, may function as a selective inhibitor of VEGF-C. We find that s9Nrp2 forms a stable dimer that potently inhibits VEGF-C/Nrp2 binding and cellular signaling. These data provide critical insight into VEGF-C/Nrp2 binding and inhibition.
血管内皮生长因子C（VEGF-C）是一种强效的淋巴管生成细胞因子，它通过两种细胞表面受体神经纤毛蛋白-2（Nrp2）和血管内皮生长因子受体-3（VEGFR-3）的协同作用来传递信号。分别与VEGF-C功能丧失和功能获得相关的疾病，即淋巴水肿和癌症，推动了对VEGF-C/Nrp2结合与抑制的研究。在此，我们证明VEGF-C与Nrp2的结合受C末端蛋白水解成熟的调控。VEGF-C C末端与Nrp2配体结合结构域复合物的结构表明，一个隐藏的Nrp2结合基序在蛋白水解后被释放，从而允许与Nrp2的b1结构域特异性结合。基于所确定的Nrp2与VEGF-C结合的结构要求，我们推测Nrp2的内源性分泌剪接形式s9Nrp2可能作为VEGF-C的选择性抑制剂发挥作用。我们发现s9Nrp2形成稳定的二聚体，能有效抑制VEGF-C/Nrp2结合和细胞信号传导。这些数据为VEGF-C/Nrp2结合与抑制提供了关键的见解。
