Eph receptors represent the largest subfamily of receptor tyrosine kinases. The Ephs and their ligands, the ephrins, are predominantly expressed in the developing and adult nervous and vascular systems, playing important roles in axon guidance and cell migration. Eph receptors are unique among other receptor kinases in that they fall into two subclasses with distinct ligand specificities, and in that they can also function as ligands activating bi-directional signaling. Understanding the mechanism of Eph/ephrin signaling and its role during development requires a detailed structural and biophysical characterization of the Eph receptors, the ephrins, and their interaction. Our studies of the extracellular functional domains of these molecules during the past five years revealed unique features not previously seen in any other receptor-ligand families and explained many of their unique biochemical and signaling properties. Our future research will continue to integrate the tools of X-ray crystallography, protein biochemistry, protein biophysics, and molecular biology into a program of detailed analysis of the Eph/ephrin recognition and signaling. By studying the three-dimensional structures of the full ectodomains of Ephs, ephrins and of the complete transmembrane molecules, as well as of their various biologically important complexes, we will gain further insight into the unique structural features of this signaling system that have placed it in the center of the development and function of the nervous system. Parallel to our crystallographic experiments will be our biophysical studies of the kinetics and thermodynamics of the ligand/receptor interactions. The combined information will provide invaluable insights into the molecular mechanisms underlying the biological functions of Ephs and ephrins The specific aims of our proposed investigations are: 1. Structural characterization of full Eph ectodomains alone and in complex with ephrins;2. Structural and biophysical characterization of the Eph/ephrin/ADAM interactions and cleavage;3. Production, structural and functional characterization of full-length (transmembrane) Eph receptors.

Public Health Relevance

Eph receptors represent the largest subfamily of receptor tyrosine kinases. The Ephs and their ligands, the Ephrins, are predominantly expressed in the developing and adult nervous and vascular systems, playing important roles in axon guidance and cell migration. Eph receptors are unique among other receptor kinases in that they fall into two subclasses with distinct ligand specificities, and in that they can also function as ligands activating bi-directional signaling. Understanding the mechanism of Eph/ephrin signaling and its role during development requires a detailed structural and biophysical characterization of the Eph receptors, the ephrins, and their interaction. We use X-ray crystallography combined with other biophysical techniques to study how these molecules recognize and interact with each other.
The specific aims of our proposed investigations are: 1. Structural characterization of full Eph ectodomains alone and in complex with ephrins;2. Structural and biophysical characterization of the Eph/ephrin/ADAM interactions and cleavage;3. Production, structural and functional characterization of full-length (transmembrane) Eph receptors.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS038486-14
Application #
8423047
Study Section
Macromolecular Structure and Function C Study Section (MSFC)
Program Officer
Mamounas, Laura
Project Start
1999-02-01
Project End
2015-01-31
Budget Start
2013-02-01
Budget End
2015-01-31
Support Year
14
Fiscal Year
2013
Total Cost
$394,919
Indirect Cost
$188,047
Name
Sloan-Kettering Institute for Cancer Research
Department
Type
DUNS #
064931884
City
New York
State
NY
Country
United States
Zip Code
10065
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Nikolov, Dimitar B; Xu, Kai; Himanen, Juha P (2013) Eph/ephrin recognition and the role of Eph/ephrin clusters in signaling initiation. Biochim Biophys Acta 1834:2160-5
Xu, Kai; Tzvetkova-Robev, Dorothea; Xu, Yan et al. (2013) Insights into Eph receptor tyrosine kinase activation from crystal structures of the EphA4 ectodomain and its complex with ephrin-A5. Proc Natl Acad Sci U S A 110:14634-9
Paavilainen, Sari; Grandy, David; Karelehto, Eveliina et al. (2013) High-level expression of a full-length Eph receptor. Protein Expr Purif 92:112-8
Xu, Kai; Xu, Yan; Rajashankar, Kanagalaghatta R et al. (2013) Crystal structures of Lgr4 and its complex with R-spondin1. Structure 21:1683-9
Ferluga, Sara; Hantgan, Roy; Goldgur, Yehuda et al. (2013) Biological and structural characterization of glycosylation on ephrin-A1, a preferred ligand for EphA2 receptor tyrosine kinase. J Biol Chem 288:18448-57
Xu, Kai; Broder, Christopher C; Nikolov, Dimitar B (2012) Ephrin-B2 and ephrin-B3 as functional henipavirus receptors. Semin Cell Dev Biol 23:116-23
Singla, Nikhil; Erdjument-Bromage, Hediye; Himanen, Juha P et al. (2011) A semisynthetic Eph receptor tyrosine kinase provides insight into ligand-induced kinase activation. Chem Biol 18:361-71
Singla, Nikhil; Goldgur, Yehuda; Xu, Kai et al. (2010) Crystal structure of the ligand-binding domain of the promiscuous EphA4 receptor reveals two distinct conformations. Biochem Biophys Res Commun 399:555-9
Kar, Rekha; Mishra, Nandita; Singha, Prajjal K et al. (2010) Mitochondrial remodeling following fission inhibition by 15d-PGJ2 involves molecular changes in mitochondrial fusion protein OPA1. Biochem Biophys Res Commun 399:548-54

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