The binding of human glial cell line-derived neurotrophic factor to heparin and heparan sulfate: importance of 2-O-sulfate groups and effect on its interaction with its receptor, GFRalpha1.
We report ELISA studies of the glycosaminoglycan binding properties of recombinant human glial cell line-derived neurotrophic factor (GDNF). We demonstrate relatively high affinity binding as soluble heparin competes with an IC50 of 0.1 micro g/ml. The binding of GDNF to heparin is particularly dependent on the presence of 2-O-sulfate groups. Highly sulfated heparan sulfate is also an effective competitor for GDNF binding. We also show that heparin at low concentrations protects GDNF from proteolytic modification by an endoprotease and also promotes the binding of GDNF to its receptor polypeptide, GFRalpha1. In both of these actions, 2-O-desulfated heparin is less effective. Considered overall, these findings provide strong support for a hypothesis that the bioactivity of GDNF during prenatal development is essentially dependent on the binding of this growth factor to 2-O-sulfate-rich heparin-related glycosaminoglycan.
Rickard
Steven M
SM
School of Biological Sciences, Royal Holloway University of London, Egham Hill, Egham, Surrey TW20 0EX, United Kingdom.
Mummery
Rosemary S
RS
Mulloy
Barbara
B
Rider
Christopher C
CC
D001665:Binding Sites; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D006493:Heparin / Q000737:chemistry / Q000378:metabolism*; D006497:Heparan Sulfate / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D020128:Inhibitory Concentration 50; D009682:Magnetic Resonance Spectroscopy; D009414:Nerve Growth Factors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009457:Neuroglia / Q000378:metabolism*; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D013431:Sulfates / Q000378:metabolism*
D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D006493:Heparin; D006497:Heparan Sulfate; D009414:Nerve Growth Factors; D011518:Proto-Oncogene Proteins; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; D013431:Sulfates; C495039:GDNF protein, human; C494987:GFRA1 protein, human