Recombinant Human IGFBP-6 Protein, CF

The superfamily of insulin-like growth factor (IGF) binding proteins include the six high-affinity IGF binding proteins (IGFBP) and at least four additional low-affinity binding proteins referred to as IGFBP related proteins (IGFBP-rP). All IGFBP superfamily members are cysteine-rich proteins with conserved cysteine residues, which are clustered in the amino- and carboxy-terminal thirds of the molecule. IGFBPs modulate the biological activities of IGF proteins. Some IGFBPs may also have intrinsic bioactivity that is independent of their ability to bind IGF proteins. Post-transitional modifications of IGFBP, including glycosylation, phosphorylation and proteolysis, have been shown to modify the affinities of the binding proteins to IGF.

Human IGFBP-6 cDNA encodes a 240 amino acid (aa) residue precursor protein with a putative 24 aa residue signal peptide that is processed to generate the 216 aa residue mature protein that is O-glycosylated. IGFBP-6 is expressed in ovarian cells, prostatic cells, and fibroblasts. IGFBP-6 is found predominantly in CSF and serum. IGFBP-6 binds preferentially to IGF-II, exhibiting a 2-fold higher affinity for IGF-II than for IGF-I.