Developing FGF2 Mutants with Selectively Reduced Heparan Sulfate Affinity to Explore their Impact on FGFR1 Signaling

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Signaling

Background:

• Fibroblast growth factor 2 (FGF2) and its receptors (FGFRs) are key regulators of biological processes.
• Heparan sulfate (HS) is proposed to act as a co-receptor modulating FGF/FGFR signaling, but its precise role remains unclear.

Purpose of the Study:

• To investigate the specific role of the FGF2/HS interaction in FGF2/FGFR1 signaling.
• To elucidate the mechanism by which HS influences FGF/FGFR signaling pathways.

Main Methods:

• Rational design of FGF2 mutants with significantly reduced HS-binding affinity using in silico analysis.
• Characterization of FGF2 mutants for HS affinity, FGFR1 binding affinity, and thermal stability.
• Cellular assays to evaluate the impact of altered FGF2/HS interaction on FGF2/FGFR1 signaling.

Main Results:

• FGF2 mutants demonstrated over a 100-fold decrease in HS affinity while maintaining FGFR1 binding and thermal stability.
• Cellular assays indicated that the FGF2/HS interaction's contribution to FGF2/FGFR1 signaling may be less significant than previously reported.
• The developed mutants specifically disrupt the FGF2-HS interaction, providing a tool for further investigation.

Conclusions:

• The direct contribution of FGF2/HS interaction to FGF2/FGFR1 signaling appears limited.
• This study provides novel FGF2 mutants that will aid in dissecting the complex roles of HS in growth factor signaling.
• Further research is warranted to fully understand the interplay between FGFs, FGFRs, and HS in biological systems.