| Post Translational Modifications | C5 precursor is first processed by the removal of 4 basic residues, forming two chains, beta and alpha, linked by a disulfide bond. During activation of the complement systems, the alpha chain is cleaved into C5a and C5b by the C5 convertase: C5b stays linked to the beta chain, while C5a is released in the plasma. The alpha chain is cleaved by the serine protease complement C2b component of the C5 convertase to generate C5a and C5b following activation by the classical, lectin and GZMK complement systems. The alpha chain is cleaved by CFB component of the C5 convertase to generate C5a and C5b following activation by the alternative complement system. |
| Function | Precursor of the C5a anaphylatoxin and complement C5b components of the complement pathways, which consist in a cascade of proteins that leads to phagocytosis and breakdown of pathogens and signaling that strengthens the adaptive immune system. Activated downstream of classical, alternative, lectin and GZMK complement pathways. Complement C5b: Component of the membrane attack complex (MAC), a multiprotein complex activated by the complement cascade, which inserts into a target cell membrane and forms a pore, leading to target cell membrane rupture and cell lysis. Complement C5b is generated following cleavage by C5 convertase and initiates formation of the MAC complex: C5b binds sequentially C6, C7, C8 and multiple copies of the pore-forming subunit C9. During MAC complex assembly, the C5b6 subcomplex, composed of complement C5b and C6, associates with the outer leaflet of target cell membrane, reducing the energy for membrane bending. C5a anaphylatoxin: Mediator of local inflammatory process released following cleavage by C5 convertase. Acts by binding to its receptor (C5AR1 or C5AR2), activating G protein-coupled receptor signaling and inducing a variety of responses including intracellular calcium release, contraction of smooth muscle, increased vascular permeability, and histamine release from mast cells and basophilic leukocytes. C5a is also a potent chemokine which stimulates the locomotion of polymorphonuclear leukocytes and directs their migration toward sites of inflammation. |
| Protein Name | Complement C5C3 And Pzp-Like Alpha-2-Macroglobulin Domain-Containing Protein 4 Cleaved Into - Complement C5 Beta Chain - Complement C5 Alpha Chain - C5a Anaphylatoxin - Complement C5bComplement C5 Alpha' Chain |
| Database Links | Reactome: R-HSA-166665Reactome: R-HSA-174577Reactome: R-HSA-375276Reactome: R-HSA-418594Reactome: R-HSA-977606 |
| Cellular Localisation | SecretedComplement C5b: SecretedTarget Cell MembraneSecreted As Soluble ProteinInserts Into The Cell Membrane Of Target CellsC5a Anaphylatoxin: Secreted |
| Alternative Protein Names | Complement C5 proteinC3 And Pzp-Like Alpha-2-Macroglobulin Domain-Containing Protein 4 Cleaved Into - Complement C5 Beta Chain - Complement C5 Alpha Chain - C5a Anaphylatoxin - Complement C5b proteinComplement C5 Alpha' Chain proteinC5 proteinCPAMD4 protein |
Information sourced from Uniprot.org
