title: Vascular endothelial growth factor receptor 2 direct interaction with nephrin links VEGF-A signals to actin in kidney podocytes.
abstract: The transmembrane protein nephrin is an essential component of slit diaphragms, the specialized cell junctions that link podocyte foot processes. Podocytes are epithelial cells that surround the glomerular capillaries in the kidney and are necessary for the organ-filtering function. Nephrin signaling complex transduces extracellular cues to the podocyte cytoskeleton and regulates podocyte shape and function. Vascular endothelial growth factor A (VEGF-A) is a required growth factor produced and secreted by podocytes. Accumulating evidence suggests a cross-talk between VEGF-A and nephrin signaling pathways. We previously showed that in vivo nephrin associates with VEGF receptor-2 (VEGFR2), the signaling receptor for VEGF-A. In the present work, we characterized the interaction between nephrin and VEGFR2 in cultured cells and in vitro. We demonstrate that nephrin-VEGFR2 interaction is direct using mass spectrometry, immunoprecipitation, GST-binding assays, and blot overlay experiments. This interaction occurs through VEGFR2 and nephrin cytoplasmic domains. Nephrin-VEGFR2 interaction is modulated by tyrosine phosphorylation of both cytoplasmic domains. Furthermore, the nephrin-VEGFR2 complex involves Nck and actin. VEGF-A signaling via this complex results in decreased cell size. We provide evidence that this multiprotein interaction occurs in cultured podocytes. We propose that the nephrin-VEGFR2 complex acts as a key mediator to transduce local VEGF-A signals to the podocyte actin cytoskeleton, regulating the foot process structure and glomerular filter integrity.
authors.affiliation: Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
authors.forename: Claudia
authors.initials: C
authors.lastname: Bertuccio
authors.forename: Delma
authors.initials: D
authors.lastname: Veron
authors.forename: Pardeep K
authors.initials: PK
authors.lastname: Aggarwal
authors.forename: Lawrence
authors.initials: L
authors.lastname: Holzman
authors.forename: Alda
authors.initials: A
authors.lastname: Tufro
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D013058:Mass Spectrometry; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000502:physiology; D050199:Podocytes / Q000166:cytology / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D015398:Signal Transduction / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics / Q000378:metabolism*
chemical_list: D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D008565:Membrane Proteins; D046912:Multiprotein Complexes; C078332:Nck protein; D015513:Oncogene Proteins; D042461:Vascular Endothelial Growth Factor A; C113267:nephrin; C467480:vascular endothelial growth factor A, mouse; D040301:Vascular Endothelial Growth Factor Receptor-2