Filamin B Plays a Key Role in Vascular Endothelial Growth Factor-induced Endothelial Cell Motility through Its Interaction with Rac-1 and Vav-2
Filamin B Plays a Key Role in Vascular Endothelial Growth Factor-induced Endothelial Cell Motility through Its Interaction with Rac-1 and Vav-2
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DOI：
10.1074/jbc.m109.062984
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发表时间：
2010-04-02
影响因子：
4.8
通讯作者：
Vinals, Francesc
中科院分区：
文献类型：
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作者：
del Valle-Perez, Beatriz;Gabriela Martinez, Vanesa;Vinals, Francesc
肌动蛋白结合蛋白细丝蛋白A（FLNA）和B（FLNB）在内皮细胞中表达，在血管发育过程中起重要作用。为了研究它们在成年内皮细胞功能中的作用，我们初步证实了它们在不同成年小鼠组织和培养细胞系中的表达模式，发现FLNB表达主要集中在内皮细胞中，而FLNA更普遍地表达。在功能上，小干扰RNA敲低内源性FLNB在人脐静脉内皮细胞抑制血管内皮生长因子（VEGF）诱导的体外血管生成，降低内皮细胞迁移能力，而FLNA消融没有改变这些参数。此外，FLNB耗尽的细胞增加了它们的基质粘附，具有更多的粘着斑。这种效应的分子机制涉及调节小GTP结合蛋白Rac-1的定位和活性，改变其下游效应物p21蛋白Cdc 42/Rac激活激酶（PAK）-4/5/6及其激活鸟嘌呤核苷酸交换因子Vav-2的激活。此外，我们的研究结果表明，在基础条件下存在信号复合物，包括FLNB，Rac-1和Vav-2，其在VEGF刺激后将进一步与VEGF 2和整合素α v β 5相互作用。总之，我们的研究结果揭示了FLNB在内皮细胞迁移和成人内皮细胞血管生成过程中的关键作用。
Actin-binding proteins filamin A (FLNA) and B (FLNB) are expressed in endothelial cells and play an essential role during vascular development. In order to investigate their role in adult endothelial cell function, we initially confirmed their expression pattern in different adult mouse tissues and cultured cell lines and found that FLNB expression is concentrated mainly in endothelial cells, whereas FLNA is more ubiquitously expressed. Functionally, small interfering RNA knockdown of endogenous FLNB in human umbilical vein endothelial cells inhibited vascular endothelial growth factor (VEGF)-induced in vitro angiogenesis by decreasing endothelial cell migration capacity, whereas FLNA ablation did not alter these parameters. Moreover, FLNB-depleted cells increased their substrate adhesion with more focal adhesions. The molecular mechanism underlying this effect implicates modulation of small GTP-binding protein Rac-1 localization and activity, with altered activation of its downstream effectors p21 protein Cdc42/Rac-activated kinase (PAK)-4/5/6 and its activating guanine nucleotide exchange factor Vav-2. Moreover, our results suggest the existence of a signaling complex, including FLNB, Rac-1, and Vav-2, under basal conditions that would further interact with VEGFR2 and integrin alpha v beta 5 after VEGF stimulation. In conclusion, our results reveal a crucial role for FLNB in endothelial cell migration and in the angiogenic process in adult endothelial cells.