IGFBP-3 and IGFBP-5 associate with the cell binding domain (CBD) of fibronectin.
We have used Surface Plasmon Resonance (SPR) - based biosensor technology to investigate the interaction of the six high affinity insulin-like growth factor binding proteins (IGFBP 1-6) with the cell binding domain (CBD) of fibronectin. Using a biotinylated derivative of the ninth and tenth TypeIII domains of FN ((9-10)FNIII), we show that IGFBP-3 and -5 bind to FN-CBD. We show that this binding is inhibited by IGF-I and that, for IGFBP-5, binding occurs through the C-terminal heparin binding domain of the protein. Using site-directed mutagenesis of (9-10)FNIII, we show both the "synergy" and RGD sites within these FN domains are required for maximum binding of both IGFBPs. We discuss the possible biological consequences of our results.
Beattie
James
J
Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom. J.Beattie@leeds.ac.uk
Kreiner
Michaela
M
Allan
Gordon J
GJ
Flint
David J
DJ
Domingues
Diana
D
van der Walle
Christopher F
CF
D000818:Animals; D005353:Fibronectins / Q000378:metabolism*; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000235:genetics / Q000378:metabolism*; D018975:Insulin-Like Growth Factor Binding Protein 5 / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D017434:Protein Structure, Tertiary / Q000235:genetics; D020349:Surface Plasmon Resonance
D005353:Fibronectins; D018972:Insulin-Like Growth Factor Binding Protein 3; D018975:Insulin-Like Growth Factor Binding Protein 5