title: RET recognition of GDNF-GFRα1 ligand by a composite binding site promotes membrane-proximal self-association.
abstract: The RET receptor tyrosine kinase is essential to vertebrate development and implicated in multiple human diseases. RET binds a cell surface bipartite ligand comprising a GDNF family ligand and a GFRα coreceptor, resulting in RET transmembrane signaling. We present a hybrid structural model, derived from electron microscopy (EM) and low-angle X-ray scattering (SAXS) data, of the RET extracellular domain (RET(ECD)), GDNF, and GFRα1 ternary complex, defining the basis for ligand recognition. RET(ECD) envelopes the dimeric ligand complex through a composite binding site comprising four discrete contact sites. The GFRα1-mediated contacts are crucial, particularly close to the invariant RET calcium-binding site, whereas few direct contacts are made by GDNF, explaining how distinct ligand/coreceptor pairs are accommodated. The RET(ECD) cysteine-rich domain (CRD) contacts both ligand components and makes homotypic membrane-proximal interactions occluding three different antibody epitopes. Coupling of these CRD-mediated interactions suggests models for ligand-induced RET activation and ligand-independent oncogenic deregulation.
authors.affiliation: Structural Biology Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.
authors.forename: Kerry M
authors.initials: KM
authors.lastname: Goodman
authors.affiliation: Structural Biology Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK; Protein Purification Facility, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.
authors.forename: Svend
authors.initials: S
authors.lastname: Kjær
authors.affiliation: Division of Structural Biology, The Institute of Cancer Research, London SW7 3RP, UK.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Beuron
authors.affiliation: Structural Biology Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.
authors.forename: Phillip P
authors.initials: PP
authors.lastname: Knowles
authors.affiliation: Structural Biology Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.
authors.forename: Agata
authors.initials: A
authors.lastname: Nawrotek
authors.affiliation: Structural Biology Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.
authors.forename: Emily M
authors.initials: EM
authors.lastname: Burns
authors.affiliation: Structural Biology Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Purkiss
authors.affiliation: Protein Purification Facility, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.
authors.forename: Roger
authors.initials: R
authors.lastname: George
authors.affiliation: Dipartimento di Biologia e Patologia Cellulare e Molecolare, Università di Napoli Federico II, via S. Pansini 5, 80131 Naples, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Santoro
authors.affiliation: Division of Structural Biology, The Institute of Cancer Research, London SW7 3RP, UK.
authors.forename: Edward P
authors.initials: EP
authors.lastname: Morris
authors.affiliation: Structural Biology Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK; Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, Malet Street, London WC1E 7HX, UK. Electronic address: neil.mcdonald@cancer.org.uk.
authors.forename: Neil Q
authors.initials: NQ
authors.lastname: McDonald
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology; D001665:Binding Sites; D016466:CHO Cells; D002462:Cell Membrane / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D000939:Epitopes / Q000276:immunology; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000737:chemistry / Q000378:metabolism*; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051096:Proto-Oncogene Proteins c-ret / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D016415:Sequence Alignment; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D000906:Antibodies; D000939:Epitopes; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D011994:Recombinant Proteins; D029961:Zebrafish Proteins; D051096:Proto-Oncogene Proteins c-ret