Interleukins and Cytokine Receptors

Interleukins

IL-2 Receptor

• The IL-2 receptor is a heterotrimeric complex consisting of α, β, and γ chains
• The α chain (CD25) is responsible for binding IL-2 with high affinity
• The β chain (CD122) is involved in signal transduction
• The γ chain (CD132) is shared with other cytokine receptors and is essential for signaling
• The IL-2 receptor is expressed on activated T cells, B cells, and natural killer cells

IL-6 Signal Transduction

• IL-6 binds to the IL-6 receptor (IL-6R) and induces the formation of a complex with gp130
• The IL-6/IL-6R/gp130 complex activates the JAK/STAT pathway, leading to the phosphorylation of STAT3
• Phosphorylated STAT3 dimerizes and translocates to the nucleus, where it regulates gene expression
• IL-6 also activates the MAPK and PI3K/Akt pathways, which regulate cell proliferation and survival

IL-33-ST2 Pathway

• IL-33 is a cytokine that binds to the ST2 receptor, which is a member of the Toll-like receptor family
• The IL-33-ST2 complex activates the MyD88-dependent pathway, leading to the activation of NF-κB and MAPKs
• The IL-33-ST2 pathway is involved in the regulation of inflammation, immune response, and tissue repair
• IL-33 is expressed in epithelial cells, endothelial cells, and immune cells, while ST2 is expressed on Th2 cells, mast cells, and basophils

IL-11 Function

• IL-11 is a cytokine that promotes the proliferation and differentiation of hematopoietic stem cells
• IL-11 is involved in the regulation of inflammation, immune response, and tissue repair
• IL-11 is produced by bone marrow stromal cells, fibroblasts, and epithelial cells
• IL-11 has been implicated in the pathogenesis of various diseases, including cancer, inflammatory disorders, and bone disorders

IL-34 Expression

• IL-34 is a cytokine that is produced by various cell types, including macrophages, dendritic cells, and epithelial cells
• IL-34 is involved in the regulation of immune response and inflammation
• IL-34 is expressed in response to inflammatory stimuli, such as LPS and TNF-α
• IL-34 has been implicated in the pathogenesis of various diseases, including autoimmune disorders and cancer

Interleukins

IL-2 Receptor

• Composed of α, β, and γ chains, with α chain (CD25) binding IL-2 with high affinity
• β chain (CD122) involved in signal transduction, γ chain (CD132) shared with other cytokine receptors and essential for signaling
• Expressed on activated T cells, B cells, and natural killer cells

IL-6 Signal Transduction

• IL-6 binds to IL-6 receptor (IL-6R), inducing complex formation with gp130
• Activates JAK/STAT pathway, phosphorylating STAT3, which dimerizes and translocates to nucleus to regulate gene expression
• Also activates MAPK and PI3K/Akt pathways, regulating cell proliferation and survival

IL-33-ST2 Pathway

• IL-33 binds to ST2 receptor, a Toll-like receptor family member
• Activates MyD88-dependent pathway, leading to NF-κB and MAPK activation
• Regulates inflammation, immune response, and tissue repair
• IL-33 expressed in epithelial cells, endothelial cells, and immune cells, while ST2 expressed on Th2 cells, mast cells, and basophils

IL-11 Function

• Promotes proliferation and differentiation of hematopoietic stem cells
• Regulates inflammation, immune response, and tissue repair
• Produced by bone marrow stromal cells, fibroblasts, and epithelial cells
• Implicated in cancer, inflammatory disorders, and bone disorders

IL-34 Expression

• Produced by macrophages, dendritic cells, and epithelial cells
• Regulates immune response and inflammation
• Expressed in response to inflammatory stimuli, such as LPS and TNF-α
• Implicated in autoimmune disorders and cancer