Homologous Superfamily

Anaphylatoxin, complement system (IPR018081)

Short name: Anaphylatoxin_comp_syst

Overlapping entries


Complement components C3, C4 and C5 are large glycoproteins that have important functions in the immune response and host defence [PMID: 1431125]. They have a wide variety of biological activities and are proteolytically activated by cleavage at a specific site, forming a- and b-fragments [PMID: 2777798]. A-fragments form distinct structural domains of approximately 76 amino acids, coded for by a single exon within the complement protein gene. The C3a, C4a and C5a components are referred to as anaphylatoxins [PMID: 2777798, PMID: 3081348]: they cause smooth muscle contraction, histamine release from mast cells, and enhanced vascular permeability [PMID: 3081348]. They also mediate chemotaxis, inflammation, and generation of cytotoxic oxygen radicals [PMID: 3081348]. The proteins are highly hydrophilic, with a mainly alpha-helical structure held together by 3 disulphide bridges [PMID: 3081348].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.