The IL-2 receptor is a multicomponent complex consisting of three subunits, alpha, beta and gamma, each of which is required for high affinity binding of IL-2. The alpha chain functions primarily in binding IL-2, whereas the beta and gamma chains contribute to IL-2 binding and are essential to IL-2-induced activation of signaling pathways leading to T cell growth. Both IL-4R and IL-7R were initially described as single chain, high-affinity ligand-binding cytokine receptors. However, it is now well established that the IL-2Rgamma chain functions as a second subunit of the high affinity IL-4R and IL-7R receptors. Consequently, the originally described subunits of these latter receptors are now referred to as IL-4Ralpha and IL-7Ralpha, respectively, while the common subunit is referred to as gammac. Although the common gamma chain enhances ligand binding in these three cytokine receptors, it has no capacity to bind these ligands on its own. There is evidence that the gammac chain is also a subunit of IL-13R.Synonyms: 582J2.1, IL-4R-alpha, IL4 Receptor alpha, IL4RA, Interleukin-4 receptor alpha chain