title: VEGFR-2 conformational switch in response to ligand binding.
abstract: VEGFR-2 is the primary regulator of angiogenesis, the development of new blood vessels from pre-existing ones. VEGFR-2 has been hypothesized to be monomeric in the absence of bound ligand, and to undergo dimerization and activation only upon ligand binding. Using quantitative FRET and biochemical analysis, we show that VEGFR-2 forms dimers also in the absence of ligand when expressed at physiological levels, and that these dimers are phosphorylated. Ligand binding leads to a change in the TM domain conformation, resulting in increased kinase domain phosphorylation. Inter-receptor contacts within the extracellular and TM domains are critical for the establishment of the unliganded dimer structure, and for the transition to the ligand-bound active conformation. We further show that the pathogenic C482R VEGFR-2 mutant, linked to infantile hemangioma, promotes ligand-independent signaling by mimicking the structure of the ligand-bound wild-type VEGFR-2 dimer.
authors.affiliation: Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, United States.
authors.forename: Sarvenaz
authors.identifier: http://orcid.org/0000-0001-5097-5509
authors.initials: S
authors.lastname: Sarabipour
authors.affiliation: Laboratory of Biomolecular Research, Molecular Cell Biology, Paul Scherrer Institute, Villigen, Switzerland.
authors.forename: Kurt
authors.initials: K
authors.lastname: Ballmer-Hofer
authors.affiliation: Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, United States.
authors.forename: Kalina
authors.identifier: http://orcid.org/0000-0003-4274-4406
authors.initials: K
authors.lastname: Hristova
mesh_terms: D006801:Humans; D008024:Ligands; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation; D011487:Protein Conformation / Q000187:drug effects*; D000072417:Protein Domains; D055503:Protein Multimerization; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D008024:Ligands; D050505:Mutant Proteins; D040301:Vascular Endothelial Growth Factor Receptor-2
keywords: biochemistry; biophysics; dimerization; model systems; signal transduction; structural biology; transmembrane domains