Interleukin-7 and Immunosenescence

Figure 1

Schematic of IL-7R signal transduction. IL-7 and its cell-surface receptor—a heterodimer consisting of the IL-7Rα and the common γ chain (γc)—form a ternary complex that engages the JAK-STAT pathway. The subsequent downstream activation of PI3K, bcl-2, and src kinases leads to gene transcription. IL-7R signal transduction is important in directing the differentiation, proliferation, and survival of immune cells including B, T, and natural killer (NK) cells. The IL-7Rα chain is shared with another receptor recognizing thymic stromal lymphopoietin (TSLP). In this scenario, the IL-7Rα noncovalently associates with the cytokine receptor-like factor 2 (CRLF2). Likewise, the γc is shared with other receptors specifically recognizing IL-2, IL-4, IL-9, IL-15, and IL-21.