Family

Insulin-like growth factor (IPR022350)

Short name: Insulin-like_growth_factor

Family relationships

Description

The insulin family of proteins groups together several evolutionarily related active peptides [PMID: 6107857]: these include insulin [PMID: 6243748, PMID: 503234], relaxin [PMID: 10601981, PMID: 8735594], insect prothoracicotropic hormone (bombyxin) [PMID: 8683595], insulin-like growth factors (IGF1 and IGF2) [PMID: 2036417, PMID: 1319992], mammalian Leydig cell-specific insulin-like peptide (gene INSL3), early placenta insulin-like peptide (ELIP) (gene INSL4), locust insulin-related peptide (LIRP), molluscan insulin-related peptides (MIP) and Caenorhabditis elegans insulin-like peptides. The 3D structures of a number of family members have been determined [PMID: 2036417, PMID: 1319992, PMID: 9141131]. The fold comprises two polypeptide chains (A and B) linked by two disulphide bonds: all share a conserved arrangement of 4 cysteines in their A chain, the first of which is linked by a disulphide bond to the third, while the second and fourth are linked by interchain disulphide bonds to cysteines in the B chain.

The IGFs, or somatomedins, play a key role in pre-adolescent mammalian growth. IGFI expression is regulated by growth hormone and mediates post-natal growth [PMID: 6382022]. Defects in IGF1 are the cause of insulin-like growth factor I deficiency (IGF1 deficiency), an autosomal recessive disorder characterised by growth retardation, sensorineural deafness and mental retardation [PMID: 8857020]. IGF2 appears to be induced by placental lactogen and is thought to play a role in foetal development [PMID: 6382022].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0008083 growth factor activity

Cellular Component

GO:0005615 extracellular space

Contributing signatures

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