title: Crosstalk between VEGF-A/VEGFR2 and GDNF/RET signaling pathways.
abstract: Vascular endothelial growth factor (VEGF-A) plays multiple roles in kidney development: stimulates cell proliferation, survival, tubulogenesis, and branching morphogenesis. However, the mechanism that mediates VEGF-A induced ureteric bud branching is unclear. Glial-derived neurotrophic factor (GDNF) signaling through tyrosine kinase c-RET is the major regulator of ureteric bud branching. Here we examined whether VEGF-A regulates RET signaling. We determined that ureteric bud-derived cells express the main VEGF-A signaling receptor, VEGFR2 and RET, by RT-PCR, immunoblotting, and immunocytochemistry. We show that the VEGF-A isoform VEGF(165) induces RET-tyr(1062) phosphorylation in addition to VEGFR2 autophosphorylation, that VEGF(165) and GDNF have additive effects on RET-tyr(1062) phosphorylation, and that VEGFR2 and RET co-immunoprecipitate. Functionally, VEGF(165) induces ureteric bud cell proliferation and branching morphogenesis. Similarly, in embryonic kidney explants VEGF(165) induces RET-tyr(1062) phosphorylation and upregulates GDNF. These findings provide evidence for a novel cooperative interaction between VEGFR2 and RET that mediates VEGF-A functions in ureteric bud cells.
authors.affiliation: Department of Pediatrics, Albert Einstein College of Medicine, Bronx, NY 10461, USA. atufro@aecom.yu.edu
authors.forename: Alda
authors.initials: A
authors.lastname: Tufro
authors.forename: Jason
authors.initials: J
authors.lastname: Teichman
authors.forename: Nazifa
authors.initials: N
authors.lastname: Banu
authors.forename: Guillermo
authors.initials: G
authors.lastname: Villegas
mesh_terms: D049108:Cell Enlargement; D002460:Cell Line; D049109:Cell Proliferation; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000378:metabolism*; D006801:Humans; D009024:Morphogenesis / Q000502:physiology*; D051096:Proto-Oncogene Proteins c-ret / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D014513:Ureter / Q000196:embryology / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism*
chemical_list: C495039:GDNF protein, human; D051100:Glial Cell Line-Derived Neurotrophic Factor; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D051096:Proto-Oncogene Proteins c-ret; C099282:RET protein, human; D040301:Vascular Endothelial Growth Factor Receptor-2