Insulin-like growth factor-binding protein 4 (IPR022327)

Short name: IGFBP-4

Overlapping homologous superfamilies


Family relationships


Insulin-like growth factors (IGFs)-I and -II are small secreted peptides that stimulate the survival, and promote the proliferation and differentiation, of many cell types [PMID: 8874492]. In biological fluids, these growth factors are usually bound to IGF binding proteins (IGFBPs), which regulate their availability and activity by prolonging their half-life and modulating their receptor interactions.

To date, six IGFBP family members have been identified (termed IGFBP1-6) [PMID: 10605625]. They share a conserved gene (intron-exon) organisation and high IGF binding affinity. Structurally, the proteins also share a common domain architecture, possessing a conserved N-terminal IGFBP domain, a highly variable mid-section, and a thyroglobulin type-1 (Tg1) domain in their C-terminal regions.

In addition to their role in the regulation of IGF activity, there is evidence for the direct association of IGFBPs with a variety of extracellular and cell surface molecules [PMID: 7504671, PMID: 7499327], with consequent effects upon important biological processes. These include modulation of bone cell proliferation [PMID: 7544787], and growth arrest of breast and prostate cancer cells [PMID: 7504671, PMID: 9115291].

IGFBP4 is abundant in serum, and is expressed in many different tissues. The protein functions as a cardiogenic growth factor in mice -an effect that is IGF-independent, and mediated by inhibition on the canonical Wnt signalling pathway [PMID: 18528331].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0005520 insulin-like growth factor binding

Cellular Component

GO:0005576 extracellular region

Contributing signatures

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