FBW7 regulates endothelial functions by targeting KLF2 for ubiquitination and degradation

• Published in: Cell research 2013-06, Vol.23 (6), p.803-819
• Main Authors: Wang, Rui, Wang, Yan, Liu, Ning, Ren, Chunguang, Jiang, Cong, Zhang, Kai, Yu, Su, Chen, Yunfei, Tang, Hui, Deng, Qi, Fu, Cong, Wang, Yingcong, Li, Rong, Liu, Mingyao, Pan, Weijun, Wang, Ping
• Format: Article
• Language: English
• Subjects: 631/443/592; 631/80/474/2073; 631/80/474/582; Adhesion; Animals; Biomedical and Life Sciences; Cell Biology; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; Cell Differentiation; Cell Line; Cell Movement; Endothelium - metabolism; F-Box Proteins - genetics; F-Box Proteins - metabolism; F-Box-WD Repeat-Containing Protein 7; Glycogen Synthase Kinase 3 - genetics; Glycogen Synthase Kinase 3 - metabolism; Human Umbilical Vein Endothelial Cells - metabolism; Humans; Inflammation; Kruppel-Like Transcription Factors - metabolism; Life Sciences; Mice; Neovascularization, Physiologic; Original; original-article; Phosphorylation; Physiology; RNA Interference; RNA, Small Interfering; RNA介导; SKP Cullin F-Box Protein Ligases - metabolism; Ubiquitin-Protein Ligases - genetics; Ubiquitin-Protein Ligases - metabolism; Ubiquitination; Zebrafish - embryology; 泛素化; 泛素连接酶; 细胞功能; 血管内皮细胞; 血管发育; 血管生成; 降解
• ISSN: 1001-0602; 1748-7838
• DOI: 10.1038/cr.2013.42

F-box and WD repeat domain-containing 7 （FBW7）, the substrate-binding subunit of E3 ubiquitin ligase St;V （a complex of SKP1, cullin-1 and FBW7）, plays important roles in various physiological and pathological processes. Although FBW7 is required for vascular development, its function in the endothelium remains to be investigated. In this study, we show that FBW7 is an important regulator of endothelial functions, including angiogenesis, leukocyte adhesion and the endothelial barrier integrity. Using RNA interference, we found that the depletion of FBW7 mark- edly impairs angiogenesis in vitro and in vivo. We identified the zinc finger transcription factor Kriippel-like factor 2 （KLF2） as a physiological target of FBW7 in endothelial cells. Knockdown of FBW7 expression resulted in the accu- mulation of endogenous KLF2 protein in endothelial cells. FBW7-mediated KLF2 destruction was shown to depend on the phosphorylation of KLF2 via glycogen synthase kinase-3 （GSK3） at two conserved phosphodegrons. Mutating these phosphodegron motifs abolished the FBW7-mediated degradation and ubiquitination of KLF2. The siRNA- mediated knockdown of FBW7 showed that KLF2 is an essential target of FBW7 in the regulation of endothelial functions. Moreover, FBW7-mediated KLF2 degradation was shown to be critical for angiogenesis in teratomas and in zebrafish development. Taken together, our study suggests a role for FBW7 in the processes of endothelial cell migration, angiogenesis, inflammation and barrier integrity, and provides novel insights into the regulation of KLF2 stability in vivo.