Chemistry for Technologies Laboratory and INSTM, School of Engineering, University of Brescia, Via Branze, 38, 25123 Brescia, Italy.
J Am Chem Soc. 2012 Sep 5;134(35):14573-9. doi: 10.1021/ja305816p. Epub 2012 Aug 23.
Vascular endothelial growth factor receptor-2 (VEGFR2) is an endothelial cell receptor that plays a pivotal role in physiologic and pathologic angiogenesis and is a therapeutic target for angiogenesis-dependent diseases, including cancer. By leveraging on a dedicated nanomechanical biosensor, we investigated the nanoscale mechanical phenomena intertwined with VEGFR2 surface recognition by its prototypic ligand VEGF-A and its noncanonical ligand gremlin. We found that the two ligands bind the immobilized extracellular domain of VEGFR2 (sVEGFR2) with comparable binding affinity. Nevertheless, they interact with sVEGFR2 with different binding kinetics and drive different in-plane piconewton intermolecular forces, suggesting that the binding of VEGF-A or gremlin induces different conformational changes in sVEGFR2. These behaviors can be effectively described in terms of a different "nanomechanical affinity" of the two ligands for sVEGFR2, about 16-fold higher for VEGF-A with respect to gremlin. Such nanomechanical differences affect the biological activity driven by the two angiogenic factors in endothelial cells, as evidenced by a more rapid VEGFR2 clustering and a more potent mitogenic response triggered by VEGF-A in respect to gremlin. Together, these data point to surface intermolecular interactions on cell membrane between activated receptors as a key modulator of the intracellular signaling cascade.
血管内皮生长因子受体-2（VEGFR2）是一种内皮细胞受体，在生理和病理血管生成中起着关键作用，是依赖血管生成的疾病（包括癌症）的治疗靶点。通过利用专用的纳米机械生物传感器，我们研究了与 VEGFR2 表面识别与其原型配体 VEGF-A 和非典型配体 GREMLIN 交织在一起的纳米级机械现象。我们发现，这两种配体以相当的结合亲和力与固定化的细胞外结构域的 VEGFR2（sVEGFR2）结合。然而，它们与 sVEGFR2 的相互作用具有不同的结合动力学，并驱动不同的面内皮牛牛顿分子间力，表明 VEGF-A 或 GREMLIN 的结合诱导 sVEGFR2 发生不同的构象变化。这些行为可以用两种配体对 sVEGFR2 的不同“纳米机械亲和力”来有效地描述，VEGF-A 相对于 GREMLIN 的亲和力约高 16 倍。这种纳米力学差异影响了两种血管生成因子在血管内皮细胞中驱动的生物学活性，因为 VEGF-A 比 GREMLIN 引起 VEGFR2 更快的聚集和更有效的有丝分裂反应。总之，这些数据表明，细胞膜上激活受体之间的表面分子间相互作用是细胞内信号级联的关键调节剂。
