C5

Complement component 5 (C5) is a protein involved in the complement system in humans, which is encoded by the C5 gene. As the fifth component of complement, C5 serves an essential role in inflammatory and cell killing processes. It is made up of alpha and beta polypeptide chains linked by a disulfide bridge, and can be cleaved into C5a and C5b. C5a is a small anaphylatoxin which enables to induce various biological responses via binding to the 7TM receptors C5aR and the C5L2. However, the large C5b fragment nucleates generation of the membrane attack complex capable of killing susceptible pathogens through the production of a pore structure in association with complement components C6, C7, C8, and C9.
Researchers have proven that C5a is present in coronary atherectomies from patients with acute coronary syndromes. And it has also demonstrated that C5a is associated with matrix metalloproteinase (MMP)-1 and -9, which may serve a key role in plaque destabilization via degradation of the extracellular matrix. Furthermore, C5a is a powerful chemotactic factor for monocytes, mast cells and T lymphocytes, resulting in the expression of adhesion molecules on endothelial cells and promoting the release of the inflammatory mediators TNF-a, IL-1, oncostatin M and the formation of reactive oxygen species by macrophages.
Gene ID: 727
UniProt ID: P01031