Impairment of ligand binding and growth signaling of mutant IL-2 receptor gamma-chains in patients with X-linked severe combined immunodeficiency.
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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.
- PubMed ID
- 8027558 [ View in PubMed]
- Abstract
The IL-2R gamma-chain is an indispensable subunit for the functional IL-2R. Recently, mutations of the gamma-chain have been reported to be closely associated with X-linked severe combined immunodeficiency (XSCID). The present study reveals that three patients with XSCID have three different mutations in the gamma-chain; a point mutation, a two consecutive-base deletion, and lack of the second exon in mRNA. The point mutation that we have detected is C to T, which results in one amino acid substitution of valine for alanine in the extracellular domain of the IL-2R gamma-chain (named AV mutant). The two-base deletion detected causes a frame shift of the coding region in the SH2 subdomain in the cytoplasmic domain (named tSH mutant). Transfection studies performed with the mutant gamma-chains demonstrated that the AV mutant and tSH mutant failed to bind to IL-2 and to transduce growth signals, respectively. These findings indicate that the gamma-chain gene mutations that accompany XSCID induce loss of the gamma-chain function, possibly resulting in stagnation of the differentiation and development of T cells.