Complement C5a

C5a is a protein fragment released from complement component C5. This 74 amino acid peptide in humans is generated by the cleavage of C5a convertase on the C5 α-chain during the classical, alternative, and lectin pathways of complement activation. The structure of C5a includes a core region consisting of four, anti-parallel alpha-helices held together by three disulfide linkages and a structured C-terminal tail, and C5a is rapidly metabolised by carboxypeptidase B to a 73 amino acid low activity form, C5a des-Arg. C5a is an extremely potent proinflammatory mediator, as well as a potent chemotactic factor for neutrophils and other leukocytes. It causes histamine release, increases in vascular permeability, induces several cytokines production from leukocytes, enhances neutrophil-endothelial cell adhesion, and augments the humoral and cell-mediated immune response. C5a is quickly metabolised by carboxypeptidases, forming the less potent C5adesArg. Acting via a classical G protein-coupled receptor, CD88, C5a and C5adesArg exert a number of effects essential to the innate immune response, while their actions at the more recently discovered non-G protein-coupled receptor, C5L2 (or GPR77), remain unclear. The widespread expression of C5a receptors throughout the body allows C5a to elicit a broad range of effects. Thus, C5a has been found to be a significant pathogenic driver in a number of immuno-inflammatory diseases, making C5a inhibition an attractive therapeutic strategy. C5a is a strong chemoattractant and is involved in the recruitment of inflammatory cells such as neutrophils, eosinophils, monocytes, and T lymphocytes, in activation of phagocytic cells and release of granule-based enzymes and generation of oxidants, all of which may contribute to innate immune functions or tissue damage. Accordingly, the anaphylatoxin C5a is implicated in a variety of diseases such as rheumatoid arthritis, systemic lupus erythematosus, reperfusion injury, Alzheimer's disease, and sepsis.

Complement C5a Related Areas

Immunology>>Innate Immunity>>Complement System>>Complement C5a

Complement C5a Alternative Names

C5a , CPAMD4, FLJ17816, FLJ17822, MGC142298

Summaries for Complement C5a

Entrez Gene summary for Complement C5a :

OMIM - description for Complement C5a :

Wikipedia summary for Complement C5a :

C5a is a protein fragment released from complement component C5. In humans, the polypeptide contains 74 amino acids. NMR spectroscopy proved that the molecule is composed of four helices and loops connecting the helices. On the N terminus a short 1.5 turn helix is also present.[1] The longest helix -IV- develops three disulfide bonds with helix II and III. C5a is rapidly metabolised by a serum enzyme, carboxypeptidase B to a 73 amino acid form, C5a des-Arg.

Human Complement C5a Protein General Information

 

• Protein names: Recommended name: C5a anaphylatoxin chemotactic receptor Short name=C5a-R Short name=C5aR
• Sequence length: 350 AA.
• Domain: Transmembrane Transmembrane helix
• Sequence similarities: Belongs to the G-protein coupled receptor 1 family.
• Post-translational modification: Sulfation plays a critical role in the association of the receptor with C5a, but no significant role in the ability of the receptor to transduce a signal and mobilize calcium in response to a small peptide agonist.
• Subunit structure: Interacts with ARRB1 and ARRB2
• Subcellular location: Cell membrane; Multi-pass membrane protein.

General information above from UniProt

Function for Complement C5a Protein

UniProtKB:

Receptor for the chemotactic and inflammatory peptide anaphylatoxin C5a. This receptor stimulates chemotaxis, granule enzyme release and superoxide anion production.

Genatlas:

• G protein coupled receptor 1 family
• C5A (anaphylatoxin) receptor
• Complement C5a stimulate chemotoxics, granule enzyme release and superoxide anion and participating in the defense of choroidal and retinal tissues during inflammation

Homology for human Complement C5a

• ortholog to murine C5r1