Essential role of Flk-1 (VEGF receptor 2) tyrosine residue 1173 in vasculogenesis in mice
Essential role of Flk-1 (VEGF receptor 2) tyrosine residue 1173 in vasculogenesis in mice
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DOI：
10.1073/pnas.0404984102
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发表时间：
2005-01-25
影响因子：
11.1
通讯作者：
Shibuya, M
中科院分区：
文献类型：
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作者：
Sakurai, Y;Ohgimoto, K;Shibuya, M
Flk-1(人类对应的KDR)酪氨酸激酶是两种血管内皮生长因子受体之一，在血管发育中起着至关重要的作用。最近，我们发现，在KDR的酪氨酸残基中，1175(Y1 175，相当于小鼠Flk-1中的Y1 173)和Y1 214(Flk-1中的Y1212)是受血管内皮生长因子(VEGF)的响应而自动磷酸化的，Y1 175在血管内皮生长因子依赖的磷脂酶Cy/PKC/丝裂原激活的蛋白激酶激活导致培养的内皮细胞DNA合成中起重要作用。然而，这些酪氨酸残基在体内Flk-1/KDR中的重要性尚不清楚。为了检验这些Flk-1酪氨酸残基在体内的作用，我们建立了分别用苯丙氨酸替换Flk-1基因的Y1173和Y1212的敲入小鼠。结果，Flk-11173F纯合子小鼠在胚胎8.5~9.5天死亡，没有任何有组织的血管或卵黄囊血岛，造血祖细胞严重减少，与Flk-1基因缺失小鼠相似。相比之下，Flk-11212F纯合子小鼠是存活和可生育的。这些结果表明，Flk-1的Y1173信号通路在胚胎发育过程中对内皮细胞和造血系统的发育起着至关重要的作用。
Flk-1 (human counterpart, KDR) tyrosine kinase, which is one of the two VEGF receptors, is crucial for vascular development. Recently, we showed that, among tyrosine residues of KDR, tyrosine residues 1175 (Y1 175, corresponding to Y1 173 in murine Flk-1) and Y1 214 (Y1 212 in Flk-1) are autophosphorylated in response to VEGF, and that Y1 175 is important for VEGF-dependent phospholipase Cy/PKC/mitogen-activated protein kinase activation leading to DNA synthesis in cultured endothelial cells. However, the importance of these tyrosine residues in Flk-1/KDR in vivo is not yet known. To examine the role of these Flk-1 tyrosine residues in vivo, we generated knock-in mice substituting Y1 173 and Y1 212 of the Flk-1 gene with phenylalanine, respectively. As a result, Flk-11173F homozygous mice died between embryonic days 8.5 and 9.5 without any organized blood vessels or yolk sac blood islands, and hematopoietic progenitors were severely reduced, similar to the case of Flk-1 null mice. In contrast, Flk-11212F homozygous mice were viable and fertile. These results suggest that the signaling via Y1173 of Flk-1 is essential for endothelial and hematopoietic development during embryogenesis.