InterPro : IPR000020

Name  Anaphylatoxin/fibulin Short Name  Anaphylatoxin/fibulin
Type  Domain Description  Complement components C3, C4 and C5 are large glycoproteins that have important functions in the immune response and host defence []. They have a wide variety of biological activities and are proteolytically activated by cleavage at a specific site, forming a- and b-fragments []. 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 [, ]: they cause smooth muscle contraction, histamine release from mast cells, and enhanced vascular permeability []. They also mediate chemotaxis, inflammation, and generation of cytotoxic oxygen radicals []. The proteins are highly hydrophilic, with a mainly alpha-helical structure held together by 3 disulphide bridges [].Fibulins are secreted glycoproteins that become incorporated into a fibrillar extracellular matrix when expressed by cultured cells or added exogenously to cell monolayers [, ]. The five known members of the family share an elongated structure and many calcium-binding sites, owing to the presence of tandem arrays of epidermal growth factor-like domains. They have overlapping binding sites for several basement-membrane proteins, tropoelastin, fibrillin, fibronectin and proteoglycans, and they participate in diverse supramolecular structures. The amino-terminal domain I of fibulin consists of three anaphylatoxin-like (AT) modules, each approximately 40 residues long and containing four or six cysteines. The structure of an AT module was determined for the complement-derived anaphylatoxin C3a, and was found to be a compact alpha-helical fold that is stabilised by three disulphide bridges in the pattern Cys1-4, Cys2-5 and Cys3-6 (where Cys is cysteine). The bulk of the remaining portion of the fibulin molecule is a series of nine EGF-like repeats [].

Sequence Features

GO Displayer


InterPro protein domain ID --> Contigs



1 Child Features

Id Name Short Name Type
IPR018081 Anaphylatoxin, complement system Anaphylatoxin_comp_syst Domain

0 Contains

1 Found In

Id Name Short Name Type
IPR017048 Fibulin-1 Fibulin-1 Family

0 Parent Features

6 Publications

First Author Title Year Journal Volume Pages
Gennaro R C5a fragment of bovine complement. Purification, bioassays, amino-acid sequence and other structural studies. 1986 Eur J Biochem 155 77-86
Ogata RT Sequence of the gene for murine complement component C4. 1989 J Biol Chem 264 16565-72
Argraves WS Fibulin is an extracellular matrix and plasma glycoprotein with repeated domain structure. 1990 J Cell Biol 111 3155-64
Pan TC Structure and expression of fibulin-2, a novel extracellular matrix protein with multiple EGF-like repeats and consensus motifs for calcium binding. 1993 J Cell Biol 123 1269-77
Fritzinger DC Primary structure of cobra complement component C3. 1992 J Immunol 149 3554-62
Timpl R Fibulins: a versatile family of extracellular matrix proteins. 2003 Nat Rev Mol Cell Biol 4 479-89

To cite PlanMine, please refer to the following publication:

Rozanski, A., Moon, H., Brandl, H., Martín-Durán, J. M., Grohme, M., Hüttner, K., Bartscherer, K., Henry, I., & Rink, J. C.
PlanMine 3.0—improvements to a mineable resource of flatworm biology and biodiversity
Nucleic Acids Research, gky1070. doi:10.1093/nar/gky1070 (2018)