Igfbp2
Developmental stage
Expressed embryos at day 11.5. Also expressed in fetal livers with expression increasing dramatically after birth. Expression decreases only slightly after postnatal day 3 and remains abundant thereafter.
Domain
The C-terminus is required for IGF-binding and growth inhibition.
Function
Multifunctional protein that plays a critical role in regulating the availability of IGFs such as IGF1 and IGF2 to their receptors and thereby regulates IGF-mediated cellular processes including proliferation, differentiation, and apoptosis in a cell-type specific manner (PubMed:18276763). Functions coordinately with receptor protein tyrosine phosphatase beta/PTPRB and the IGF1 receptor to regulate IGF1-mediated signaling by stimulating the phosphorylation of PTEN leading to its inactivation and AKT1 activation (PubMed:26773517). Plays a positive role in cell migration via interaction with integrin alpha5/ITGA5 through an RGD motif. Additionally, interaction with ITGA5/ITGB1 enhances the adhesion of endothelial progenitor cells to endothelial cells. Upon mitochondrial damage, facilitates apoptosis with ITGA5 of podocytes, and then activates the phosphorylation of focal adhesion kinase (FAK)-mediated mitochondrial injury.
Post-translational modifications
Cleaved by MMP9 leading to release of free IGF2 from IGFBP2-IGF2 complex, which contributes to enhance the motility and the growth of astrocytes.
O-glycosylated.
Tissue Specificity
Highly expressed in adult liver, but also in kidney, lung, brain, spleen, testis and ovary.
Cellular localization
- Secreted
Alternative names
Igfbp-2, Igfbp2, Insulin-like growth factor-binding protein 2, IBP-2, IGF-binding protein 2, IGFBP-2, mIGFBP-2