The extracellular domain of fibroblast growth factor receptor 3 inhibits ligand-independent dimerization.
Dysregulation of the ligand-independent dimerization of receptor tyrosine kinases (RTKs), which is the first step in the activation of RTKs, leads to various pathologies. A mechanistic understanding of the dimerization process is lacking, and this lack of basic knowledge is one bottleneck in the development of effective RTK-targeted therapies. For example, the roles and relative contributions of the different domains of RTKs to receptor dimerization are unknown. Here, we used quantitative imaging Förster resonance energy transfer (QI-FRET) to determine the contribution of the extracellular domain of fibroblast growth factor receptor 3 (FGFR3) to the dimerization of the receptor. We provide evidence that the contribution of the extracellular domain of FGFR3 to dimerization is repulsive in the absence of ligand and is on the order of ~1 kcal/mol. The repulsive contribution of the extracellular domain is similar in magnitude, but opposite in sign, to the contribution of pathogenic single-amino acid mutations to RTK signaling, and is therefore likely to be important for biological function. Together, these results highlight the fine balance in the domain interactions that regulate RTK dimerization and signaling.
Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
Lirong
L
Chen
Jesse
J
Placone
Lawrence
L
Novicky
Kalina
K
Hristova
D019943:Amino Acid Substitution; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D017705:Lignans; D051379:Mice; D020125:Mutation, Missense; D055503:Protein Multimerization / Q000502:physiology*; D017434:Protein Structure, Tertiary; D051498:Receptor, Fibroblast Growth Factor, Type 3 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology
D017705:Lignans; C496365:FGFR3 protein, human; D051498:Receptor, Fibroblast Growth Factor, Type 3