FGFR3 dimer stabilization due to a single amino acid pathogenic mutation

J Mol Biol. 2006 Feb 24;356(3):600-12. doi: 10.1016/j.jmb.2005.11.077. Epub 2005 Dec 12.

Abstract

Mutations in the transmembrane (TM) domains of receptor tyrosine kinases (RTKs) have been implicated in the induction of pathological phenotypes. These mutations are believed to stabilize the RTK dimers, and thus promote unregulated signaling. However, the energetics behind the pathology induction has not been determined. An example of a TM domain pathogenic mutation is the Ala391-->Glu mutation in fibroblast growth factor receptor 3 (FGFR3), linked to Crouzon syndrome with acanthosis nigricans, as well as to bladder cancer. Here, we determine the free energy of dimerization of wild-type and mutant FGFR3 TM domain in lipid bilayers using Förster resonance energy transfer, and we show that hydrogen bonding between Glu391 and the adjacent helix in the dimer is a feasible mechanism for dimer stabilization. The measured change in the free energy of dimerization due to the Ala391-->Glu pathogenic mutation is -1.3 kcal/mol, consistent with previous reports of hydrogen bond strengths in proteins. This is the first quantitative measurement of mutant RTK stabilization in a membrane environment. We show that this seemingly modest value can lead to a large increase in dimer fraction and thus profoundly affect RTK-mediated signal transduction.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alanine / genetics
  • Amino Acid Sequence
  • Amino Acid Substitution / genetics*
  • Cell Membrane / genetics
  • Craniofacial Dysostosis / genetics
  • Dimerization
  • Electrophoresis, Polyacrylamide Gel
  • Fluorescence Resonance Energy Transfer
  • Glutamic Acid / genetics
  • Humans
  • Liposomes
  • Models, Molecular
  • Molecular Sequence Data
  • Mutation*
  • Protein Structure, Secondary / genetics
  • Protein Structure, Tertiary / genetics
  • Receptor, Fibroblast Growth Factor, Type 3 / chemistry*
  • Receptor, Fibroblast Growth Factor, Type 3 / genetics*
  • Receptor, Fibroblast Growth Factor, Type 3 / metabolism
  • Signal Transduction / genetics
  • Thermodynamics
  • Urinary Bladder Neoplasms / genetics

Substances

  • Liposomes
  • Glutamic Acid
  • FGFR3 protein, human
  • Receptor, Fibroblast Growth Factor, Type 3
  • Alanine