Human Interleukin 2 Receptor, Gamma (IL2RG) Protein

Background

The Interleukin 2 Receptor Subunit Gamma (IL2RG), also known as the common gamma chain or γc, is a crucial component of several cytokine receptor complexes, specifically those for interleukin-2 (IL-2), IL-4, IL-7, IL-9, IL-15, and IL-21. Each of these cytokines plays a vital role in immune cell development, activation, and homeostasis. Because IL2RG is part of multiple cytokine receptor systems, it is often referred to as a "common" subunit, essential for the signaling functionality of these cytokines. The expression of IL2RG is indispensable for immune competence, influencing processes in adaptive immunity and innate immune responses. In its absence, severe immunodeficiency conditions, such as X-linked severe combined immunodeficiency (X-SCID), can occur, indicating its role in T cell, B cell, and natural killer (NK) cell development. IL2RG does not directly bind to cytokines but facilitates signal transduction by forming a complex with cytokine-specific receptor subunits and initiating intracellular signaling cascades. The signaling through IL2RG activates critical pathways, including JAK/STAT, MAPK, and PI3K/AKT, which are integral to immune cell differentiation, proliferation, and survival. Due to the centrality of IL2RG in immune system function, mutations in this gene have severe implications for immune cell functionality and host defense.