|2erj, resolution 3.00Å ()|
|Gene:||IL2RA (Homo sapiens), IL2RB (Homo sapiens), IL2RG (Homo sapiens), IL2 (Homo sapiens)|
Crystal structure of the heterotrimeric interleukin-2 receptor in complex with interleukin-2
IL-2 is a cytokine that functions as a growth factor and central regulator in the immune system and mediates its effects through ligand-induced hetero-trimerization of the receptor subunits IL-2R alpha, IL-2R beta, and gamma(c). Here, we describe the crystal structure of the trimeric assembly of the human IL-2 receptor ectodomains in complex with IL-2 at 3.0 A resolution. The quaternary structure is consistent with a stepwise assembly from IL-2/IL-2R alpha to IL-2/IL-2R alpha/IL-2R beta to IL-2/IL-2R alpha/IL-2R beta/gamma(c). The IL-2R alpha subunit forms the largest of the three IL-2/IL-2R interfaces, which, together with the high abundance of charge-charge interactions, correlates well with the rapid association rate and high-affinity interaction of IL-2R alpha with IL-2 at the cell surface. Surprisingly, IL-2R alpha makes no contacts with IL-2R beta or gamma(c), and only minor changes are observed in the IL-2 structure in response to receptor binding. These findings support the principal role of IL-2R alpha to deliver IL-2 to the signaling complex and act as regulator of signal transduction. Cooperativity in assembly of the final quaternary complex is easily explained by the extraordinarily extensive set of interfaces found within the fully assembled IL-2 signaling complex, which nearly span the entire length of the IL-2R beta and gamma(c) subunits. Helix A of IL-2 wedges tightly between IL-2R beta and gamma(c) to form a three-way junction that coalesces into a composite binding site for the final gamma(c) recruitment. The IL-2/gamma(c) interface itself exhibits the smallest buried surface and the fewest hydrogen bonds in the complex, which is consistent with its promiscuous use in other cytokine receptor complexes.
Crystal structure of the IL-2 signaling complex: paradigm for a heterotrimeric cytokine receptor., Stauber DJ, Debler EW, Horton PA, Smith KA, Wilson IA, Proc Natl Acad Sci U S A. 2006 Feb 21;103(8):2788-93. Epub 2006 Feb 13. PMID:16477002
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
[IL2_HUMAN] Note=A chromosomal aberration involving IL2 is found in a form of T-cell acute lymphoblastic leukemia (T-ALL). Translocation t(4;16)(q26;p13) with involves TNFRSF17. [IL2RA_HUMAN] Genetic variations in IL2RA are associated with susceptibility to diabetes mellitus insulin-dependent type 10 (IDDM10) [MIM:601942]. A multifactorial disorder of glucose homeostasis that is characterized by susceptibility to ketoacidosis in the absence of insulin therapy. Clinical fetaures are polydipsia, polyphagia and polyuria which result from hyperglycemia-induced osmotic diuresis and secondary thirst. These derangements result in long-term complications that affect the eyes, kidneys, nerves, and blood vessels. [IL2RG_HUMAN] Defects in IL2RG are the cause of severe combined immunodeficiency X-linked T-cell-negative/B-cell-positive/NK-cell-negative (XSCID) [MIM:300400]; also known as agammaglobulinemia Swiss type. A form of severe combined immunodeficiency (SCID), a genetically and clinically heterogeneous group of rare congenital disorders characterized by impairment of both humoral and cell-mediated immunity, leukopenia, and low or absent antibody levels. Patients present in infancy recurrent, persistent infections by opportunistic organisms. The common characteristic of all types of SCID is absence of T-cell-mediated cellular immunity due to a defect in T-cell development. Defects in IL2RG are the cause of X-linked combined immunodeficiency (XCID) [MIM:312863]. XCID is a less severe form of X-linked immunodeficiency with a less severe degree of deficiency in cellular and humoral immunity than that seen in XSCID.
[IL2_HUMAN] Produced by T-cells in response to antigenic or mitogenic stimulation, this protein is required for T-cell proliferation and other activities crucial to regulation of the immune response. Can stimulate B-cells, monocytes, lymphokine-activated killer cells, natural killer cells, and glioma cells. [IL2RA_HUMAN] Receptor for interleukin-2. [IL2RG_HUMAN] Common subunit for the receptors for a variety of interleukins. [IL2RB_HUMAN] Receptor for interleukin-2. This beta subunit is involved in receptor mediated endocytosis and transduces the mitogenic signals of IL2.
About this Structure
- Stauber DJ, Debler EW, Horton PA, Smith KA, Wilson IA. Crystal structure of the IL-2 signaling complex: paradigm for a heterotrimeric cytokine receptor. Proc Natl Acad Sci U S A. 2006 Feb 21;103(8):2788-93. Epub 2006 Feb 13. PMID:16477002
- ↑ Lowe CE, Cooper JD, Brusko T, Walker NM, Smyth DJ, Bailey R, Bourget K, Plagnol V, Field S, Atkinson M, Clayton DG, Wicker LS, Todd JA. Large-scale genetic fine mapping and genotype-phenotype associations implicate polymorphism in the IL2RA region in type 1 diabetes. Nat Genet. 2007 Sep;39(9):1074-82. Epub 2007 Aug 5. PMID:17676041 doi:10.1038/ng2102
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- ↑ Pepper AE, Buckley RH, Small TN, Puck JM. Two mutational hotspots in the interleukin-2 receptor gamma chain gene causing human X-linked severe combined immunodeficiency. Am J Hum Genet. 1995 Sep;57(3):564-71. PMID:7668284
- ↑ Clark PA, Lester T, Genet S, Jones AM, Hendriks R, Levinsky RJ, Kinnon C. Screening for mutations causing X-linked severe combined immunodeficiency in the IL-2R gamma chain gene by single-strand conformation polymorphism analysis. Hum Genet. 1995 Oct;96(4):427-32. PMID:7557965
- ↑ Puck JM, Pepper AE, Bedard PM, Laframboise R. Female germ line mosaicism as the origin of a unique IL-2 receptor gamma-chain mutation causing X-linked severe combined immunodeficiency. J Clin Invest. 1995 Feb;95(2):895-9. PMID:7860773 doi:http://dx.doi.org/10.1172/JCI117740
- ↑ Stephan V, Wahn V, Le Deist F, Dirksen U, Broker B, Muller-Fleckenstein I, Horneff G, Schroten H, Fischer A, de Saint Basile G. Atypical X-linked severe combined immunodeficiency due to possible spontaneous reversion of the genetic defect in T cells. N Engl J Med. 1996 Nov 21;335(21):1563-7. PMID:8900089 doi:10.1056/NEJM199611213352104
- ↑ Jones AM, Clark PA, Katz F, Genet S, McMahon C, Alterman L, Cant A, Kinnon C. B-cell-negative severe combined immunodeficiency associated with a common gamma chain mutation. Hum Genet. 1997 May;99(5):677-80. PMID:9150740
- ↑ Schmalstieg FC, Leonard WJ, Noguchi M, Berg M, Rudloff HE, Denney RM, Dave SK, Brooks EG, Goldman AS. Missense mutation in exon 7 of the common gamma chain gene causes a moderate form of X-linked combined immunodeficiency. J Clin Invest. 1995 Mar;95(3):1169-73. PMID:7883965 doi:http://dx.doi.org/10.1172/JCI117765
- ↑ Sharfe N, Shahar M, Roifman CM. An interleukin-2 receptor gamma chain mutation with normal thymus morphology. J Clin Invest. 1997 Dec 15;100(12):3036-43. PMID:9399950 doi:10.1172/JCI119858