Division of Molecular Medicine and Genetics, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA.
J Cell Biol. 2010 Jun 14;189(6):955-65. doi: 10.1083/jcb.200912094. Epub 2010 Jun 7.
Focal adhesion kinase (FAK) is essential for vascular development as endothelial cell (EC)-specific knockout of FAK (conditional FAK knockout [CFKO] mice) leads to embryonic lethality. In this study, we report the differential kinase-independent and -dependent functions of FAK in vascular development by creating and analyzing an EC-specific FAK kinase-defective (KD) mutant knockin (conditional FAK knockin [CFKI]) mouse model. CFKI embryos showed apparently normal development through embryonic day (E) 13.5, whereas the majority of CFKO embryos died at the same stage. Expression of KD FAK reversed increased EC apoptosis observed with FAK deletion in embryos and in vitro through suppression of up-regulated p21. However, vessel dilation and defective angiogenesis of CFKO embryos were not rescued in CFKI embryos. ECs without FAK or expressing KD FAK showed increased permeability, abnormal distribution of vascular endothelial cadherin (VE-cadherin), and reduced VE-cadherin Y658 phosphorylation. Together, our data suggest that kinase-independent functions of FAK can support EC survival in vascular development through E13.5 but are insufficient for maintaining EC function to allow for completion of embryogenesis.
黏着斑激酶（FAK）对于血管发育是必需的，因为内皮细胞（EC）特异性 FAK 敲除（条件性 FAK 敲除[CFKO]小鼠）会导致胚胎致死。在这项研究中，我们通过创建和分析内皮细胞特异性 FAK 激酶缺陷（KD）突变嵌合（条件性 FAK 嵌合[CFKI]）小鼠模型，报告了 FAK 在血管发育中的差异的激酶非依赖性和依赖性功能。CFKI 胚胎通过胚胎第 13.5 天（E）显示出明显正常的发育，而大多数 CFKO 胚胎在同一阶段死亡。KD FAK 的表达通过抑制上调的 p21，逆转了在胚胎中和体外观察到的 FAK 缺失引起的 EC 凋亡增加。然而，CFKO 胚胎的血管扩张和血管生成缺陷在 CFKI 胚胎中未得到挽救。没有 FAK 或表达 KD FAK 的 EC 表现出增加的通透性、血管内皮钙黏蛋白（VE-cadherin）的异常分布和 VE-cadherin Y658 磷酸化减少。总之，我们的数据表明，FAK 的激酶非依赖性功能可以通过 E13.5 来支持血管发育中 EC 的存活，但不足以维持 EC 功能以完成胚胎发生。
