Abstract
The conventional concept is that the insulin-like growth factor binding proteins (IGFBPs) are cysteine-rich proteins, with conserved N- and C- domains, that are capable of binding insulin-like growth factors (IGFs) with high affinity. This dogma was recently challenged by the discovery of a group of cysteine-rich proteins that share important structural similarities with the IGFBPs, but have demonstrably lower affinity for IGFs. It is therefore proposed that these IGFBP-related proteins (IGFBP-rPs) and the IGFBPs constitute an IGFBP superfamily. We speculate that the IGFBP superfamily is derived from an ancestral gene/protein that was critically involved in the regulation of cell growth and was capable of binding IGF peptides. Over the course of evolution, some members (IGFBPs) evolved into high-affinity IGF binders and others (IGFBP-rPs) into low-affinity IGF binders, thereby conferring on the IGFBP superfamily the ability to influence cell growth by both IGF-dependent and IGF-independent means.
Original language | English (US) |
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Pages (from-to) | 37-45 |
Number of pages | 9 |
Journal | Acta Paediatrica, International Journal of Paediatrics, Supplement |
Volume | 88 |
Issue number | 428 |
State | Published - 1999 |
Keywords
- Insulin-like growth factor binding protein
- Insulin-like growth factor binding protein-related protein
- Superfamily
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health