Cutting edge: identification of a pre-ligand assembly domain (PLAD) and ligand binding site in the IL-17 receptor.
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.
Kramer
Jill M
JM
Department of Oral Biology, University at Buffalo, State University of New York, Buffalo, NY 14214, USA.
Hanel
Walter
W
Shen
Fang
F
Isik
Nilgun
N
Malone
James P
JP
Maitra
Amarnath
A
Sigurdson
Wade
W
Swart
David
D
Tocker
Joel
J
Jin
Tian
T
Gaffen
Sarah L
SL
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
C109985:IL17RA protein, human; D020381:Interleukin-17; D008024:Ligands; D053722:Receptors, Interleukin-17