C5a receptor

C5a receptor (also known as CD88) is a protein that in humans is encoded by the C5AR1 gene. It is a G protein-coupled receptor for C5a, a protein fragment released in response to inflammation. The C5a receptor is expressed on a variety of cells, including neutrophils, monocytes, macrophages, and endothelial cells, and plays a key role in the regulation of immune response and inflammatory reactions.

Structure

The C5a receptor is a seven-transmembrane, G protein-coupled receptor. It is approximately 350 amino acids in length, with the N-terminus located extracellularly and the C-terminus located intracellularly. The receptor has a high affinity for C5a, but can also bind to C5a des-Arg, a less potent form of C5a.

Function

The primary function of the C5a receptor is to bind to C5a, a potent chemotactic factor that attracts immune cells to the site of inflammation. Upon binding to C5a, the receptor undergoes a conformational change that triggers the activation of intracellular signaling pathways, leading to a variety of cellular responses, including chemotaxis, phagocytosis, and the release of proinflammatory cytokines.

Clinical significance

The C5a receptor has been implicated in a number of inflammatory diseases, including asthma, rheumatoid arthritis, and sepsis. Inhibition of the C5a receptor has been proposed as a therapeutic strategy for these conditions. Several C5a receptor antagonists are currently under investigation in clinical trials.

See also

• Complement system
• G protein-coupled receptor
• Inflammation

References

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