Article

Regulation of vascular endothelial growth factor receptor 2 trafficking and angiogenesis by Golgi localized t-SNARE syntaxin 6

Department of Anatomy and Cell Biology, University of Iowa, 51 Newton Rd., Iowa City, IA 52242, USA.
Blood (Impact Factor: 10.45). 11/2010; 117(4):1425-35. DOI: 10.1182/blood-2010-06-291690
Source: PubMed
ABSTRACT
Vascular endothelial growth factor receptor 2 (VEGFR2) plays a key role in physiologic and pathologic angiogenesis. Plasma membrane (PM) levels of VEGFR2 are regulated by endocytosis and secretory transport through the Golgi apparatus. To date, the mechanism whereby the VEGFR2 traffics through the Golgi apparatus remains incompletely characterized. We show in human endothelial cells that binding of VEGF to the cell surface localized VEGFR2 stimulates exit of intracellular VEGFR2 from the Golgi apparatus. Brefeldin A treatment reduced the level of surface VEGFR2, confirming that VEGFR2 traffics through the Golgi apparatus en route to the PM. Mechanistically, we show that inhibition of syntaxin 6, a Golgi-localized target membrane-soluble N-ethylmaleimide attachment protein receptor (t-SNARE) protein, interferes with VEGFR2 trafficking to the PM and facilitates lysosomal degradation of the VEGFR2. In cell culture, inhibition of syntaxin 6 also reduced VEGF-induced cell proliferation, cell migration, and vascular tube formation. Furthermore, in a mouse ear model of angiogenesis, an inhibitory form of syntaxin 6 reduced VEGF-induced neovascularization and permeability. Our data demonstrate the importance of syntaxin 6 in the maintenance of cellular VEGFR2 levels, and suggest that the inhibitory form of syntaxin 6 has good potential as an antiangiogenic agent.

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    • "Published studies using human endothelial cells have shown that syntaxin 6 (Stx6), a member of the target membrane-associated SNARE (t-SNARE) family protein is associated with VEGFR2/KDR and alpha5 beta1 integrin trafficking and angiogenesis [55]. SNARE protein may have important roles in cancer cell signaling, progression, invasion and onset of cancer through different mechanism. "
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    • "For example, VEGF-A 165 -stimulated signal transduction requires co-ordination of VEGFR2 tyrosine kinase activation with residence at different locations within the endocytic pathway e.g. plasma membrane and endosomes (Gourlaouen et al., 2013; Jopling et al., 2009; Koch et al., 2014; Lanahan et al., 2013 Lanahan et al., , 2010 Lanahan et al., , 2014 Manickam et al., 2011; Nakayama et al., 2013; Yamada et al., 2014; Zhang et al., 2013). Plasma membrane VEGFR2 activation promotes recruitment of phospholipase Cγ1 thus stimulating phosphatidylinositol-4,5- bisphosphate (PIP 2 ) hydrolysis to generate inositol-1,4,5- trisphosphate (IP 3 ) and diacylglycerol (DAG): these molecules act as second messengers that promote cytosolic calcium ion flux and protein kinase C activation respectively (Meyer et al., 2003; Takahashi and Shibuya, 1997; Wong and Jin, 2005). "
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    • "Published studies using human endothelial cells have shown that syntaxin 6 (Stx6), a member of the target membrane-associated SNARE (t-SNARE) family protein is associated with VEGFR2/KDR and alpha5 beta1 integrin trafficking and angiogenesis [55]. SNARE protein may have important roles in cancer cell signaling, progression, invasion and onset of cancer through different mechanism. "
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