Cytokine receptor common subunit gamma (IL2RG) (IL2RG)

The cytokine receptor common subunit gamma, also known as the common gamma chain (γc) or CD132, is a critical transmembrane protein that serves as a shared signaling component for the receptors of several key cytokines, including interleukin-2 (IL-2), IL-4, IL-7, IL-9, IL-15, and IL-21 (UniProt P31785). Within the IL-2 receptor system, the common gamma chain is an indispensable part of both the intermediate-affinity (composed of IL-2Rβ and γc) and high-affinity (composed of IL-2Rα, IL-2Rβ, and γc) complexes (PubMed: 22449609). Its primary function is to initiate intracellular signal transduction by recruiting Janus kinase 3 (JAK3) to the receptor complex upon ligand binding. This recruitment subsequently activates the STAT5 signaling pathway to drive the proliferation and differentiation of T cells, B cells, and natural killer cells (NCBI Gene: 3561). Mutations in the IL2RG gene lead to X-linked severe combined immunodeficiency (X-SCID), a life-threatening condition characterized by the failure of lymphocyte development (StatPearls: NBK559033). In clinical practice, the common gamma chain is a target for immunotherapies; IL-2 and IL-15 agonists are used to stimulate anti-tumor immunity in cancers like melanoma and renal cell carcinoma, while monoclonal antibodies targeting the receptor complex are employed to prevent organ transplant rejection and treat certain T-cell leukemias (PubMed: 28475224).

Other names

Common gamma chainCD132Interleukin-2 receptor subunit gammaGamma-cIL-2RGIL2RGSCIDXSCIDX1

The common gamma chain acts as a signaling subunit that, upon binding of interleukins (such as IL-2 or IL-15) to the receptor complex, recruits and activates Janus kinase 3 (JAK3). This activation triggers the phosphorylation of STAT5, initiating gene transcription programs essential for lymphocyte survival and expansion. Therapeutic agents either mimic these cytokines to stimulate the immune system or block the receptor complex to suppress unwanted immune responses.