Structural determinants of growth factor binding and specificity by VEGF receptor 2
Structural determinants of growth factor binding and specificity by VEGF receptor 2
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DOI：
10.1073/pnas.0914318107
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发表时间：
2010-02-09
影响因子：
11.1
通讯作者：
Alitalo, Kari
中科院分区：
文献类型：
--
作者：
Leppanen, Veli-Matti;Prota, Andrea E.;Alitalo, Kari
血管内皮生长因子(VEGFs)通过激活VEGFR-1、VEGFR-2和VEGFR-3三种受体来调节血管和淋巴管的形成。血管内皮生长因子受体的胞外区由7个免疫球蛋白同源结构域组成，当与配体结合时，促进受体二聚化。二聚化启动跨膜信号，激活受体的细胞内酪氨酸激酶结构域。血管内皮生长因子-C通过VEGFR-3刺激淋巴管生成，参与病理性血管生成。然而，经蛋白降解处理的血管内皮生长因子-C也刺激VEGFR-2，VEGFR-2是生理和病理血管生成所需的主要信号转导。在这里，我们介绍了结合在VEGFR-2高亲和力结合部位的血管内皮生长因子-C的晶体结构，它由免疫球蛋白同源结构域D2和D3组成。这种结构揭示了一个对称的2：2复合体，其中左手扭曲的受体结构域包裹在血管内皮生长因子-C的2倍轴上。在血管内皮生长因子中，受体的特异性由N端的α螺旋和三个肽环决定。我们的结构表明，VEGF-C中的两个环与VEGFR-2亚域D2和D3结合，而一个环主要与D3相互作用。此外，VEGF-C的N端螺旋与D2相互作用，分隔两个VEGF-C单体的沟槽与D2/D3接头结合。与血管内皮生长因子-A不同，血管内皮生长因子-C不结合血管内皮生长因子受体-1。因此，我们创造了VEGFR-1/VEGFR-2嵌合蛋白来进一步研究受体的特异性。这一生化分析结合我们的结构数据，确定了对血管内皮生长因子-A和血管内皮生长因子C结合至关重要的VEGFR-2残基。我们的结果对决定血管内皮生长因子/血管内皮生长因子受体相互作用的高亲和力和特异性的结构特征提供了重要的见解。
Vascular endothelial growth factors (VEGFs) regulate blood and lymph vessel formation through activation of three receptor tyrosine kinases, VEGFR-1, -2, and -3. The extracellular domain of VEGF receptors consists of seven immunoglobulin homology domains, which, upon ligand binding, promote receptor dimerization. Dimerization initiates transmembrane signaling, which activates the intracellular tyrosine kinase domain of the receptor. VEGF-C stimulates lymphangiogenesis and contributes to pathological angiogenesis via VEGFR-3. However, proteolytically processed VEGF-C also stimulates VEGFR-2, the predominant transducer of signals required for physiological and pathological angiogenesis. Here we present the crystal structure of VEGF-C bound to the VEGFR-2 high-affinity-binding site, which consists of immunoglobulin homology domains D2 and D3. This structure reveals a symmetrical 2: 2 complex, in which left-handed twisted receptor domains wrap around the 2-fold axis of VEGF-C. In the VEGFs, receptor specificity is determined by an N-terminal alpha helix and three peptide loops. Our structure shows that two of these loops in VEGF-C bind to VEGFR-2 subdomains D2 and D3, while one interacts primarily with D3. Additionally, the N- terminal helix of VEGF-C interacts with D2, and the groove separating the two VEGF-C monomers binds to the D2/D3 linker. VEGF-C, unlike VEGF-A, does not bind VEGFR-1. We therefore created VEGFR-1/VEGFR-2 chimeric proteins to further study receptor specificity. This biochemical analysis, together with our structural data, defined VEGFR-2 residues critical for the binding of VEGF-A and VEGF-C. Our results provide significant insights into the structural features that determine the high affinity and specificity of VEGF/VEGFR interactions.