response to interleukin-2

Definition

Target type: biologicalprocess

Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of an interleukin-2 stimulus. [GOC:mah]

Interleukin-2 (IL-2), a cytokine primarily produced by activated T cells, plays a crucial role in immune responses by regulating the proliferation, differentiation, and survival of immune cells, particularly T cells. The response to IL-2 is a complex process involving multiple signaling pathways and transcription factors, ultimately leading to the activation of target genes involved in cell cycle progression, effector function, and survival.

Upon binding to its receptor, IL-2 receptor (IL-2R), a trimeric complex composed of IL-2Rα, IL-2Rβ, and IL-2Rγ, IL-2 triggers a cascade of intracellular signaling events. The binding of IL-2 to its receptor initiates the activation of the Janus kinase (JAK) family of tyrosine kinases, specifically JAK1 and JAK3. Activated JAKs phosphorylate tyrosine residues on the cytoplasmic tails of IL-2Rβ and IL-2Rγ, creating docking sites for the signal transducer and activator of transcription (STAT) proteins, particularly STAT5.

STAT5 proteins bind to the phosphorylated tyrosine residues on IL-2Rβ and IL-2Rγ and are subsequently phosphorylated by JAKs. Phosphorylated STAT5 dimers translocate to the nucleus, where they bind to specific DNA sequences called STAT5 binding sites in the promoters of target genes. These target genes include those involved in cell cycle progression, such as cyclin D1 and c-myc, and genes encoding effector molecules like IFN-γ and TNF-α.

Activation of STAT5 signaling pathway leads to the upregulation of anti-apoptotic proteins such as Bcl-xL, which promotes cell survival. The IL-2 response also involves the activation of other signaling pathways, such as the PI3K/AKT pathway, which contributes to cell survival and proliferation.

In addition to promoting proliferation and differentiation, IL-2 plays a role in the development and maintenance of regulatory T cells (Tregs), which suppress immune responses and prevent autoimmunity. IL-2 signaling in Tregs is crucial for their development, survival, and function.

The response to IL-2 is tightly regulated, ensuring appropriate immune responses while avoiding excessive inflammation. Negative feedback mechanisms control IL-2 signaling, including the expression of suppressor of cytokine signaling (SOCS) proteins, which inhibit JAK activity, and the induction of the E3 ubiquitin ligase Cbl-b, which promotes the degradation of IL-2Rβ.

In summary, the response to IL-2 is a multifaceted process that plays a vital role in immune regulation. IL-2 signaling activates multiple pathways leading to cell proliferation, differentiation, survival, and the development of Tregs. These processes are crucial for mounting effective immune responses while maintaining immune homeostasis.'
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Proteins (2)

Compounds (136)