IL1R

The IL1R, or Interleukin-1 Receptor, is a cell surface receptor that plays a crucial role in the immune system. It is part of the larger superfamily of Toll-like receptors, which are involved in detecting pathogens and initiating immune responses. There are two main types of IL1R: the type I receptor (IL1R1) and the type II receptor (IL1R2).

IL1R1 is a signaling receptor. When activated by its ligands, Interleukin-1 alpha (IL-1α) and Interleukin-1 beta (IL-1β), it triggers intracellular signaling cascades. These cascades lead to the activation of transcription factors, such as NF-κB, which in turn promote the production of inflammatory cytokines and other immune mediators. This makes IL1R1 a key player in inflammation, fever, and the acute phase response.

IL1R2, on the other hand, is a non-signaling decoy receptor. It can bind to IL-1α and IL-1β but does not initiate a downstream signaling cascade. Instead, it acts to sequester the IL-1 cytokines, thereby downregulating the inflammatory response mediated by IL1R1. This inhibitory function is important for preventing excessive or prolonged inflammation.

Both IL1R1 and IL1R2 are expressed on a variety of cell types, including immune cells like macrophages and T cells, as well as non-immune cells such as fibroblasts and endothelial cells. The expression and activity of IL1Rs are tightly regulated, ensuring appropriate immune responses. Dysregulation of IL-1 signaling through IL1R can contribute to various inflammatory and autoimmune diseases.