Ciliary neurotrophic factor, cardiotrophin-like cytokine, and neuropoietin share a conserved binding site on the ciliary neurotrophic factor receptor alpha chain.
Ciliary neurotrophic factor, cardiotrophin-like cytokine, and neuropoietin are members of the four-helix bundle cytokine family. These proteins signal through a common tripartite receptor composed of leukemia inhibitory factor receptor, gp130, and ciliary neurotrophic factor receptor alpha. Binding to ciliary neurotrophic factor receptor alpha occurs through an interaction site located at the C terminus of the cytokine AB loop and alphaD helix, known as site 1. In the present study, we have generated a model of neuropoietin and identified a conserved binding site for the three cytokines interacting with ciliary neurotrophic factor receptor alpha. To identify the counterpart of this site on ciliary neurotrophic factor receptor alpha, its cytokine binding domain was modeled, and the physicochemical properties of its surface were analyzed. This analysis revealed an area displaying properties complementary to the site 1 of ciliary neurotrophic factor, cardiotrophin-like cytokine, and neuropoietin. Based on our computational predictions, residues were selected for their potential involvement in the ciliary neurotrophic factor receptor alpha binding epitope, and site-directed mutagenesis was carried out. Biochemical, cell proliferation, and cell signaling analyses showed that Phe(172) and Glu(286) of ciliary neurotrophic factor receptor alpha are key interaction residues. Our results demonstrated that ciliary neurotrophic factor, cardiotrophin-like cytokine, and neuropoietin share a conserved binding site on ciliary neurotrophic factor receptor alpha.
Rousseau
François
F
Unité Mixte INSERM 564, Bâtiment Monteclair, 4 Rue Larrey, 49033 Angers Cedex 01, France.
Chevalier
Sylvie
S
Guillet
Catherine
C
Ravon
Elisa
E
Diveu
Caroline
C
Froger
Josy
J
Barbier
Fabien
F
Grimaud
Linda
L
Gascan
Hugues
H
D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D049109:Cell Proliferation; D002522:Chlorocebus aethiops; D020934:Ciliary Neurotrophic Factor / Q000737:chemistry*; D016207:Cytokines / Q000737:chemistry*; D000939:Epitopes / Q000737:chemistry; D006801:Humans; D015850:Interleukin-6 / Q000737:chemistry*; D051379:Mice; D008954:Models, Biological; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017386:Sequence Homology, Amino Acid
D020934:Ciliary Neurotrophic Factor; D016207:Cytokines; D000939:Epitopes; D015850:Interleukin-6; C121169:cardiotrophin-like cytokine; C486482:neuropoietin, mouse