Figure 1.

The IL-7/IL-7R Pathway. The IL-7R is composed of a γC and Rα polypeptide. The Rα component is unique to the IL-7R, whereas γC is common to several cytokine-mediated pathways, including IL-2, IL-4, IL-9, IL-15 and IL-21. The binding of IL-7 to Rα results in the dimerization of γC and Rα. JAK3 is associated with γC. After dimerization of γC with Rα, JAK3 can phosphorylate Rα and/or JAK1. Activation of JAK3 results in phosphorylation of STAT5. Phosphorylation of STAT5 is required for STAT5 to act as a transcription factor (reviewed in [26]).