The function of Ensembl gene identifier ENSG00000106804 (C5, complement C5) is as follows. 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 (PubMed:12878586, PubMed:18204047, PubMed:30643019, PubMed:6554279). Activated downstream of classical, alternative, lectin and GZMK complement pathways (PubMed:12878586, PubMed:18204047, PubMed:30643019, PubMed:39914456, PubMed:39814882, PubMed:6554279). {ECO:0000269|PubMed:12878586, ECO:0000269|PubMed:18204047, ECO:0000269|PubMed:30643019, ECO:0000269|PubMed:39814882, ECO:0000269|PubMed:39914456, ECO:0000269|PubMed:6554279}. [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 (PubMed:26841837, PubMed:27052168, PubMed:30552328, PubMed:30643019). 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 (PubMed:30552328, PubMed:30643019). 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 (PubMed:30552328, PubMed:32569291). {ECO:0000269|PubMed:26841837, ECO:0000269|PubMed:27052168, ECO:0000269|PubMed:30552328, ECO:0000269|PubMed:30643019, ECO:0000269|PubMed:32569291}. [C5a anaphylatoxin]: Mediator of local inflammatory process released following cleavage by C5 convertase (PubMed:8182049, PubMed:9553099). 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 (PubMed:36806352, PubMed:37852260, PubMed:37169960, PubMed:8182049, PubMed:9553099). C5a is also a potent chemokine which stimulates the locomotion of polymorphonuclear leukocytes and directs their migration toward sites of inflammation (PubMed:342601, PubMed:37852260, PubMed:37169960, PubMed:5765461, PubMed:8182049, PubMed:9553099). {ECO:0000269|PubMed:342601, ECO:0000269|PubMed:36806352, ECO:0000269|PubMed:37169960, ECO:0000269|PubMed:37852260, ECO:0000269|PubMed:5765461, ECO:0000269|PubMed:8182049, ECO:0000269|PubMed:9553099}.