Figure 1: The family of cytokines sharing the common cytokine-receptor γ c in their receptor complexes. Each cytokine binds to a specific α chain, which forms a receptor complex with the γ c. In case of IL-2 and IL-15, trimeric high affinity complexes, which include common IL-2Rβ and γ c chains, can be formed. Each receptor complex mediates signal transduction through JAK1 and/or JAK3 and different STAT molecules. Tyr-phosphorylated STAT dimers regulate transcription of specific cytokine-sensitive genes.