title: Structures of the EphA2 Receptor at the Membrane: Role of Lipid Interactions.
abstract: Ephs are transmembrane receptors that mediate cell-cell signaling. The N-terminal ectodomain binds ligands and enables receptor clustering, which activates the intracellular kinase. Relatively little is known about the function of the membrane-proximal fibronectin domain 2 (FN2) of the ectodomain. Multiscale molecular dynamics simulations reveal that FN2 interacts with lipid bilayers via a site comprising K441, R443, R465, Q462, S464, S491, W467, F490, and P459-461. FN2 preferentially binds anionic lipids, a preference that is reduced in the mutant K441E + R443E. We confirm these results by measuring the binding of wild-type and mutant FN2 domains to lipid vesicles. In simulations of the complete EphA2 ectodomain plus the transmembrane region, we show that FN2 anchors the otherwise flexible ectodomain at the surface of the bilayer. Altogether, our data suggest that FN2 serves a dual function of interacting with anionic lipids and constraining the structure of the EphA2 ectodomain to adopt membrane-proximal configurations.
authors.affiliation: Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Chavent
authors.affiliation: Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK; Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK.
authors.forename: Elena
authors.initials: E
authors.lastname: Seiradake
authors.affiliation: Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK.
authors.forename: E Yvonne
authors.initials: EY
authors.lastname: Jones
authors.affiliation: Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK. Electronic address: mark.sansom@bioch.ox.ac.uk.
authors.forename: Mark S P
authors.initials: MS
authors.lastname: Sansom
mesh_terms: D001665:Binding Sites; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D009154:Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D036104:Receptor, EphA2 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D008051:Lipid Bilayers; D036104:Receptor, EphA2