Homodimerization controls the fibroblast growth factor 9 subfamily's receptor binding and heparan sulfate-dependent diffusion in the extracellular matrix

Kalinina, Juliya, Byron, Sara, Makarenkova, Helen, Olsen, Shaun, Eliseenkova, Anna, Larochelle, William, Dhanabal, Mohanraj, Blais, Steven, Ornitz, David, Day, Loren, Neubert, Thomas, Pollock, Pamela, & Mohammadi, Moosa (2009) Homodimerization controls the fibroblast growth factor 9 subfamily's receptor binding and heparan sulfate-dependent diffusion in the extracellular matrix. Molecular and Cellular Biology, 29(17), pp. 4663-4678.

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Uncontrolled fibroblast growth factor (FGF) signaling can lead to human diseases, necessitating multiple layers of self-regulatory control mechanisms to keep its activity in check. Herein, we demonstrate that FGF9 and FGF20 ligands undergo a reversible homodimerization, occluding their key receptor binding sites. To test the role of dimerization in ligand autoinhibition, we introduced structure-based mutations into the dimer interfaces of FGF9 and FGF20. The mutations weakened the ability of the ligands to dimerize, effectively increasing the concentrations of monomeric ligands capable of binding and activating their cognate FGF receptor in vitro and in living cells. Interestingly, the monomeric ligands exhibit reduced heparin binding, resulting in their increased radii of heparan sulfate-dependent diffusion and biologic action, as evidenced by the wider dilation area of ex vivo lung cultures in response to implanted mutant FGF9-loaded beads. Hence, our data demonstrate that homodimerization autoregulates FGF9 and FGF20's receptor binding and concentration gradients in the extracellular matrix. Our study is the first to implicate ligand dimerization as an autoregulatory mechanism for growth factor bioactivity and sets the stage for engineering modified FGF9 subfamily ligands, with desired activity for use in both basic and translational research.

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ID Code: 44357
Item Type: Journal Article
Refereed: Yes
Additional Information: Articles free to read on journal website after 6 months
DOI: 10.1128/MCB.01780-08
ISSN: 0270-7306
Subjects: Australian and New Zealand Standard Research Classification > BIOLOGICAL SCIENCES (060000) > BIOCHEMISTRY AND CELL BIOLOGY (060100)
Divisions: Past > QUT Faculties & Divisions > Faculty of Science and Technology
Deposited On: 24 Aug 2011 22:10
Last Modified: 05 Feb 2015 05:55

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