4nux | pdb_00004nux
Structure of receptor A
Structural highlights
Disease[I17RA_HUMAN] Defects in IL17RA are the cause of familial candidiasis type 5 (CANDF5) [MIM:613953]. CANDF5 is a rare disorder with altered immune responses and impaired clearance of fungal infections, selective against Candida. It is characterized by persistent and/or recurrent infections of the skin, nails and mucous membranes caused by organisms of the genus Candida, mainly Candida albicans.[1] Function[I17RA_HUMAN] Receptor for IL17A, IL17F and, in dimer with IL17RE, for IL17C. Binds its IL17A ligand with low affinity, suggesting that additional components are involved in IL17A-induced signaling.[2] [3] Publication Abstract from PubMedInterleukin 17 (IL-17) cytokines play a crucial role in mediating inflammatory and autoimmune diseases. A unique intracellular signaling domain termed SEFIR is found within all IL-17 receptors (IL-17Rs) as well as the key adaptor protein Act1. SEFIR-mediated protein-protein interaction is a crucial step in IL-17 cytokine signaling. Here, the 2.3 A resolution crystal structure of the SEFIR domain of IL-17RA, the most commonly shared receptor for IL-17 cytokine signaling, is reported. The structure includes the complete SEFIR domain and an additional alpha-helical C-terminal extension, which pack tightly together to form a compact unit. Structural comparison between the SEFIR domains of IL-17RA and IL-17RB reveals substantial differences in protein topology and folding. The uniquely long insertion between strand betaC and helix alphaC in IL-17RA SEFIR is mostly well ordered, displaying a helix (alphaCC'ins) and a flexible loop (CC'). The DD' loop in the IL-17RA SEFIR structure is much shorter; it rotates nearly 90 degrees with respect to the counterpart in the IL-17RB SEFIR structure and shifts about 12 A to accommodate the alphaCC'ins helix without forming any knots. Helix alphaC was identified as critical for its interaction with Act1 and IL-17-stimulated gene expression. The data suggest that the heterotypic SEFIR-SEFIR association via helix alphaC is a conserved and signature mechanism specific for IL-17 signaling. The structure also suggests that the downstream motif of IL-17RA SEFIR together with helix alphaC could provide a composite ligand-binding surface for recruiting Act1 during IL-17 signaling. Structure of the unique SEFIR domain from human interleukin 17 receptor A reveals a composite ligand-binding site containing a conserved alpha-helix for Act1 binding and IL-17 signaling.,Zhang B, Liu C, Qian W, Han Y, Li X, Deng J Acta Crystallogr D Biol Crystallogr. 2014 May;70(Pt 5):1476-83. doi:, 10.1107/S1399004714005227. Epub 2014 Apr 30. PMID:24816115[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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