The structure of IL-13 in complex with IL-13Ralpha2
[IL13_HUMAN] Defects in IL13 may be a cause of susceptibility to allergic rhinitis (ALRH) [MIM:607154]. Allergic rhinitis is a common disease of complex inheritance and is characterized by mucosal inflammation caused by allergen exposure.
[I13R2_HUMAN] Binds as a monomer with high affinity to interleukin-13 (IL13), but not to interleukin-4 (IL4). [IL13_HUMAN] Cytokine. Inhibits inflammatory cytokine production. Synergizes with IL2 in regulating interferon-gamma synthesis. May be critical in regulating inflammatory and immune responses.
Publication Abstract from PubMed
Interleukin-13 is a cytokine important for development of T helper cell type 2 (Th2) responses and plays a critical role in asthma and allergy. The IL-13 Receptor alpha2 (IL-13Ralpha2) is a receptor for IL-13 lacking canonical Jak/STAT signaling functions. Here we present the crystal structure along with a mutational and biophysical analysis of the IL-13/IL-13Ralpha2 complex. While retaining a similar mode of IL-13 binding to its related signaling receptor, IL-13Ralpha1, IL-13Ralpha2 uses peripheral receptor residues unused in the IL-13/IL-13Ralpha1 complex to generate a larger and more complementary interface for IL-13. This results in a four orders of magnitude increase in affinity, to the femtomolar level, compared to IL-13Ralpha1. Alanine scanning mutagenesis of the IL-13 interface reveals several common "hotspot" residues important for binding to both receptors, but also identifies a prominent IL-13Ralpha2-specific contact. These results provide a framework for development of receptor subtype-selective IL-13 antagonists and indicate a decoy function for IL-13Ralpha2.
Molecular basis for shared cytokine recognition revealed in the structure of an unusually high affinity complex between IL-13 and IL-13Ralpha2.,Lupardus PJ, Birnbaum ME, Garcia KC Structure. 2010 Mar 10;18(3):332-42. PMID:20223216
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.