Duval Martine, Le Boeuf Fabrice, Huot Jacques, Gratton Jean-Philippe
Laboratory of Endothelial Cell Biology, Institut de recherches cliniques de Montréal (IRCM), Montréal, QC, H2W 1R7, Canada.
Mol Biol Cell. 2007 Nov;18(11):4659-68. doi: 10.1091/mbc.e07-05-0467. Epub 2007 Sep 12.
Nitric oxide (NO) release from endothelial cells, via endothelial NO synthase (eNOS) activation, is central to the proangiogenic actions of vascular endothelial growth factor (VEGF). VEGF signaling to eNOS is principally mediated by an Akt-dependent phosphorylation of eNOS and by increased association of eNOS to the molecular chaperone, heat-shock protein 90 kDa (Hsp90). Herein, we report that VEGFR-2 activation induces tyrosine phosphorylation of VEGF receptor 2 (VEGFR-2)-associated Hsp90beta. Tyrosine phosphorylation of Hsp90beta in response to VEGF is dependent on internalization of the VEGFR-2 and on Src kinase activation. Furthermore, we demonstrate that c-Src directly phosphorylates Hsp90 on tyrosine 300 residue and that this event is essential for VEGF-stimulated eNOS association to Hsp90 and thus NO release from endothelial cells. Our work identifies Y300 phosphorylation of Hsp90 as a novel regulated posttranslational modification of the chaperone and demonstrates its importance in the proangiogenic actions of VEGF, namely by regulating NO release from endothelial cells.
通过内皮型一氧化氮合酶（eNOS）激活，内皮细胞释放一氧化氮（NO）是血管内皮生长因子（VEGF）促血管生成作用的核心。VEGF向eNOS的信号传导主要由eNOS的Akt依赖性磷酸化以及eNOS与分子伴侣热休克蛋白90 kDa（Hsp90）的结合增加介导。在此，我们报告VEGFR-2激活诱导与VEGF受体2（VEGFR-2）相关的Hsp90β的酪氨酸磷酸化。响应VEGF时，Hsp90β的酪氨酸磷酸化依赖于VEGFR-2的内化和Src激酶激活。此外，我们证明c-Src直接将Hsp90的酪氨酸300残基磷酸化，并且该事件对于VEGF刺激的eNOS与Hsp90的结合以及因此内皮细胞释放NO至关重要。我们的工作将Hsp90的Y300磷酸化鉴定为伴侣蛋白的一种新型调节性翻译后修饰，并证明了其在VEGF促血管生成作用中的重要性，即通过调节内皮细胞释放NO。
