IL2 Protein – Interleukin-2 Protein (IL2)

More Information about IL2 Protein

IL2 protein also known as Interleukin-2 is a type of cytokine signaling molecule. It is involved in immune system signaling. IL2 protein are produced by T-cells. It binds to IL2 receptors expressed by lymphocytes more precisely CD4+ T cells and CD8+ T cells and can stimulate monocytes, natural killer cells, monocytes and glioma cells. This protein is important in T and B lymphocyte proliferation.

IL2 protein is involved in 3 different signaling pathways, JAK-STAT, PI3K/Akt/mTOR and MAPK/ERK pathway. IL2 protein binds to its receptor which causes the dimerization of CD122 and CD132 . This step is key for the activation of Janus kinases, more specifically JAK1 and JAK3. Janus kinase are a type of tyrosine kinases that transduce cytokine signals. The activation of JAK1 and JAK3 results in the activation of T338 on CD122 which is essential for the dimerization of STAT transcription factors. In this case it is mainly STAT5 proteins. The dimerized form of STAT migrates to the cell nucleus where it binds to the DNA.

IL2 gene expression is regulated, among others, by T-cell receptor (TCR) signaling. The latter is a molecule located on the T cell membrane and is responsible for antigen recognition. TCR signaling pathway involves phospholipase-C dependent cascade. The latter results in the activation of three different transcription factors and their respective pathways. These major transcription factors are NFAT, AP-1 and NFkB. All the members of NFAT family of proteins are located in the cytoplasm. NFAT proteins migrate to nucleus upon dephosphorylation. AP-1 is a dimer complex that cooperates with other transcription factors such as Oct and NFkB. The latter is a heterodimer and contains two binding sites for IL2 promoter. NFkB protein complex is costimulated by CD28 which is a protein expressed also on T cells and is involved in T cell activation and survival.