C5aC5aR

C5aC5aR, also known as the C5a anaphylatoxin receptor or complement component 5a receptor 1, is a protein encoded by the C5AR1 gene in humans. This receptor is a G protein-coupled receptor that plays a crucial role in the innate immune system. Its primary function is to bind to the complement fragment C5a, a potent anaphylatoxin.

Upon binding of C5a, the C5aR initiates a signaling cascade within the cell. This signaling leads to a variety of inflammatory responses, including neutrophil chemotaxis, degranulation, and increased vascular permeability. These processes are essential for recruiting immune cells to sites of infection or tissue damage and for initiating an inflammatory response.

The C5aR is expressed on a wide range of immune cells, such as neutrophils, eosinophils, monocytes, macrophages, and mast cells, as well as on some non-immune cells including endothelial cells and smooth muscle cells. Its widespread distribution highlights its broad involvement in immune regulation and inflammation.

Dysregulation of C5aR signaling has been implicated in various inflammatory and autoimmune diseases, including rheumatoid arthritis, inflammatory bowel disease, and sepsis. Consequently, the C5aR is a target for therapeutic intervention, with several drugs designed to block its activity being developed for the treatment of these conditions. Research continues to explore the multifaceted roles of C5aR in health and disease.