Where are IL-1 receptors located?
IL-1 acts on target cells by binding with high affinity (Kd of 10−10 m) to IL-1 type I receptors. Type I receptors are found on T cells, endothelial cells, hepatocytes, fibroblasts and keratinocytes, whereas type II receptors appear to have a more restricted distribution.
Where is IL-1 found?
IL-1 is intensely produced by tissue macrophages, monocytes, fibroblasts, and dendritic cells, but is also expressed by B lymphocytes, NK cells, microglia, and epithelial cells. They form an important part of the inflammatory response of the body against infection.
What is the IL-1 pathway?
IL-1 promotes the recruitment of inflammatory cells at the site of inflammation by inducing the expression of adhesion molecules on endothelial cells and through the release of chemokines by stromal cells.
Is IL-1 an inflammatory?
IL-1 (which refers here to both IL-1α and IL-1β) is a prototypical proinflammatory cytokine that stimulates both local and systemic responses. In some circumstances these effects are detrimental, such as in chronic inflammatory diseases and septic shock.
What are the members of the IL-1 family of receptors?
As shown in Table 1, there are 10 members of the IL-1 family of receptors. 9 IL-1R1 binds IL-1α, IL-1β, and IL-1Ra. IL-1R3 (formerly IL-1R accessory protein) is the coreceptor for forming a trimeric signaling complex with IL-1α or IL-1β. As shown in Figure 2, in the resting state, IL-1R1 and IL-1R3 are present on the cell membrane.
What is the difference between TLR and IL-1 receptors?
The TIR domain is nearly the same and present in each TLR and each IL-1 receptor family. Whereas IL-1 family cytokine members trigger innate inflammation via IL-1 family of receptors, TLRs trigger inflammation via bacteria, microbial products, viruses, nucleic acids, and damage-associated molecular patterns (DAMPs).
How does IL-1ra interact with the interleukin-1 (IL-1) receptor accessory protein?
Comparison of the IL-1 receptor (IL-1RI) bound to IL-1β and IL-1Ra, combined with earlier mutagenesis work, revealed how IL-1Ra can compete with IL-1β for binding its primary receptor yet prevent engagement of the co-receptor IL-1 receptor accessory protein (IL-1RAcP) ( 7, 8) and, thus, inhibit IL-1 signaling.
What are the subfamilies of the IL-1 superfamily?
The numerous cytokines and receptors in the IL-1 superfamily are further classified into four subfamilies, dependent on their distinct cognate receptors—the IL-1, IL-33, and IL-36 subfamilies share IL-1RAcP as their secondary receptor, while IL-18 subfamily utilizes a distinct secondary receptor.