| Structural highlights
Disease
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.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] 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.[11] [12]
Function
IL2RG_HUMAN Common subunit for the receptors for a variety of interleukins.
Publication Abstract from PubMed
Ligand-induced dimerization is the predominant mechanism through which secreted proteins activate cell surface receptors to transmit essential biological signals. Cytokines are a large class of soluble proteins that dimerize transmembrane receptors into precise signaling topologies, but there is a need for alternative, engineerable ligand scaffolds that specifically recognize and stabilize these protein interactions. Recombinant antibodies can potentially serve as robust and versatile platforms for cytokine complex stabilization, and their specificity allows for tunable modulation of dimerization equilibrium. Here, we devised an evolutionary strategy to isolate monovalent antibody agonists that bridge together two different receptor subunits in a cytokine-receptor complex, precisely as the receptors are disposed in their natural signaling orientations. To do this, we screened a naive antibody library against a stabilized ligand/receptor ternary complex that acted as a 'molecular cast' of the natural receptor dimer conformation. Our selections elicited 'stapler' single-chain variable fragments (scFvs) of antibodies that specifically engage the interleukin-4 receptor heterodimer. The 3.1 A resolution crystal structure of one such stapler revealed that, as intended, this scFv recognizes a composite epitope between the two receptors as they are positioned in the complex. Extending our approach, we evolved a stapler scFv that specifically binds to and stabilizes the interface between the interleukin-2 cytokine and one of its receptor subunits, leading to a 15-fold enhancement in interaction affinity. This demonstration that scFvs can be selected to recognize epitopes that span protein interfaces presents new opportunities to engineer structurally defined antibodies for a broad range of research and therapeutic applications.
A strategy for the selection of monovalent antibodies that span protein dimer interfaces.,Spangler JB, Moraga I, Jude KM, Savvides CS, Garcia KC J Biol Chem. 2019 Aug 6. pii: RA119.009213. doi: 10.1074/jbc.RA119.009213. PMID:31387945[13]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Puck JM, Deschenes SM, Porter JC, Dutra AS, Brown CJ, Willard HF, Henthorn PS. The interleukin-2 receptor gamma chain maps to Xq13.1 and is mutated in X-linked severe combined immunodeficiency, SCIDX1. Hum Mol Genet. 1993 Aug;2(8):1099-104. PMID:8401490
- ↑ DiSanto JP, Dautry-Varsat A, Certain S, Fischer A, de Saint Basile G. Interleukin-2 (IL-2) receptor gamma chain mutations in X-linked severe combined immunodeficiency disease result in the loss of high-affinity IL-2 receptor binding. Eur J Immunol. 1994 Feb;24(2):475-9. PMID:8299698
- ↑ Markiewicz S, Subtil A, Dautry-Varsat A, Fischer A, de Saint Basile G. Detection of three nonsense mutations and one missense mutation in the interleukin-2 receptor gamma chain gene in SCIDX1 that differently affect the mRNA processing. Genomics. 1994 May 1;21(1):291-3. PMID:8088810 doi:http://dx.doi.org/10.1006/geno.1994.1265
- ↑ Ishii N, Asao H, Kimura Y, Takeshita T, Nakamura M, Tsuchiya S, Konno T, Maeda M, Uchiyama T, Sugamura K. Impairment of ligand binding and growth signaling of mutant IL-2 receptor gamma-chains in patients with X-linked severe combined immunodeficiency. J Immunol. 1994 Aug 1;153(3):1310-7. PMID:8027558
- ↑ DiSanto JP, Rieux-Laucat F, Dautry-Varsat A, Fischer A, de Saint Basile G. Defective human interleukin 2 receptor gamma chain in an atypical X chromosome-linked severe combined immunodeficiency with peripheral T cells. Proc Natl Acad Sci U S A. 1994 Sep 27;91(20):9466-70. PMID:7937790
- ↑ 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
- ↑ Spangler JB, Moraga I, Jude KM, Savvides CS, Garcia KC. A strategy for the selection of monovalent antibodies that span protein dimer interfaces. J Biol Chem. 2019 Aug 6. pii: RA119.009213. doi: 10.1074/jbc.RA119.009213. PMID:31387945 doi:http://dx.doi.org/10.1074/jbc.RA119.009213
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