Regulation of vascular endothelial growth factor receptor 2 trafficking and angiogenesis by Golgi localized t-SNARE syntaxin 6.
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.
Department of Anatomy and Cell Biology, University of Iowa, 51 Newton Rd., Iowa City, IA 52242, USA.
Venkatraman
V
Manickam
Ajit
A
Tiwari
Jae-Joon
JJ
Jung
Resham
R
Bhattacharya
Apollina
A
Goel
Debabrata
D
Mukhopadhyay
Amit
A
Choudhury
D000818:Animals; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D006056:Golgi Apparatus / Q000378:metabolism*; D006801:Humans; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000502:physiology*; D021381:Protein Transport / Q000187:drug effects; D050765:Qa-SNARE Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D050600:SNARE Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism*
D050765:Qa-SNARE Proteins; D050600:SNARE Proteins; D042461:Vascular Endothelial Growth Factor A; D040301:Vascular Endothelial Growth Factor Receptor-2