Identification of fibroblast growth factor receptor 3 (FGFR3) as a protein receptor for botulinum neurotoxin serotype A (BoNT/A)

PLoS Pathog. 2013;9(5):e1003369. doi: 10.1371/journal.ppat.1003369. Epub 2013 May 16.

Abstract

Botulinum neurotoxin serotype A (BoNT/A) causes transient muscle paralysis by entering motor nerve terminals (MNTs) where it cleaves the SNARE protein Synaptosomal-associated protein 25 (SNAP25206) to yield SNAP25197. Cleavage of SNAP25 results in blockage of synaptic vesicle fusion and inhibition of the release of acetylcholine. The specific uptake of BoNT/A into pre-synaptic nerve terminals is a tightly controlled multistep process, involving a combination of high and low affinity receptors. Interestingly, the C-terminal binding domain region of BoNT/A, HC/A, is homologous to fibroblast growth factors (FGFs), making it a possible ligand for Fibroblast Growth Factor Receptors (FGFRs). Here we present data supporting the identification of Fibroblast Growth Factor Receptor 3 (FGFR3) as a high affinity receptor for BoNT/A in neuronal cells. HC/A binds with high affinity to the two extra-cellular loops of FGFR3 and acts similar to an agonist ligand for FGFR3, resulting in phosphorylation of the receptor. Native ligands for FGFR3; FGF1, FGF2, and FGF9 compete for binding to FGFR3 and block BoNT/A cellular uptake. These findings show that FGFR3 plays a pivotal role in the specific uptake of BoNT/A across the cell membrane being part of a larger receptor complex involving ganglioside- and protein-protein interactions.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Botulinum Toxins, Type A / genetics
  • Botulinum Toxins, Type A / metabolism*
  • Cell Membrane / genetics
  • Cell Membrane / metabolism*
  • HEK293 Cells
  • Humans
  • Mice
  • PC12 Cells
  • Protein Transport / genetics
  • Rats
  • Receptor, Fibroblast Growth Factor, Type 3 / genetics
  • Receptor, Fibroblast Growth Factor, Type 3 / metabolism*
  • Synaptosomal-Associated Protein 25 / genetics
  • Synaptosomal-Associated Protein 25 / metabolism

Substances

  • SNAP25 protein, human
  • Snap25 protein, mouse
  • Snap25 protein, rat
  • Synaptosomal-Associated Protein 25
  • Fgfr3 protein, rat
  • FGFR3 protein, human
  • Fgfr3 protein, mouse
  • Receptor, Fibroblast Growth Factor, Type 3
  • Botulinum Toxins, Type A