title: Cutting edge: identification of a pre-ligand assembly domain (PLAD) and ligand binding site in the IL-17 receptor.
abstract: IL-17 is the hallmark cytokine of the newly described "Th17" lymphocyte population. The composition, subunit dynamics, and ligand contacts of the IL-17 receptor are poorly defined. We previously demonstrated that the IL-17RA subunit oligomerizes in the membrane without a ligand. In this study, computational modeling identified two fibronectin-III-like (FN) domains in IL-17RA connected by a nonstructured linker, which we predicted to mediate homotypic interactions. In yeast two-hybrid, the membrane-proximal FN domain (FN2), but not the membrane-distal domain (FN1), formed homomeric interactions. The ability of FN2 to drive ligand-independent multimerization was verified by coimmunoprecipitation and fluorescence resonance energy transfer microscopy. Thus, FN2 constitutes a "pre-ligand assembly domain" (PLAD). Further studies indicated that the FN2 linker domain contains the IL-17 binding site, which was never mapped. However, the FN1 domain is also required for high affinity interactions with IL-17. Therefore, although the PLAD is located entirely within FN2, effective ligand binding also involves contributions from the linker and FN1.
authors.affiliation: Department of Oral Biology, University at Buffalo, State University of New York, Buffalo, NY 14214, USA.
authors.forename: Jill M
authors.initials: JM
authors.lastname: Kramer
authors.forename: Walter
authors.initials: W
authors.lastname: Hanel
authors.forename: Fang
authors.initials: F
authors.lastname: Shen
authors.forename: Nilgun
authors.initials: N
authors.lastname: Isik
authors.forename: James P
authors.initials: JP
authors.lastname: Malone
authors.forename: Amarnath
authors.initials: A
authors.lastname: Maitra
authors.forename: Wade
authors.initials: W
authors.lastname: Sigurdson
authors.forename: David
authors.initials: D
authors.lastname: Swart
authors.forename: Joel
authors.initials: J
authors.lastname: Tocker
authors.forename: Tian
authors.initials: T
authors.lastname: Jin
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Gaffen
mesh_terms: D001665:Binding Sites / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D020381:Interleukin-17 / Q000276:immunology / Q000378:metabolism; D008024:Ligands; D008214:Lymphocytes / Q000276:immunology / Q000378:metabolism; D008958:Models, Molecular; D010449:Peptide Mapping; D011485:Protein Binding / Q000235:genetics / Q000276:immunology; D020836:Protein Structure, Quaternary / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D053722:Receptors, Interleukin-17 / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D020798:Two-Hybrid System Techniques
chemical_list: C109985:IL17RA protein, human; D020381:Interleukin-17; D008024:Ligands; D053722:Receptors, Interleukin-17