The extracellular domain of fibroblast growth factor receptor 3 inhibits ligand-independent dimerization.

Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
Science Signaling (Impact Factor: 7.65). 11/2010; 3(150):ra86. DOI: 10.1126/scisignal.2001195
Source: PubMed

ABSTRACT 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.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Receptor Tyrosine Kinases (RTKs) conduct biochemical signals upon dimerization in the membrane plane. While RTKs are generally known to be activated in response to ligand binding, many of these receptors are capable of forming unliganded dimers that are likely important intermediates in the signaling process. All 58 RTKs consist of an extracellular domain, a transmembrane (TM) domain, and an intracellular domain which includes a juxtamembrane (JM) sequence and a kinase domain. Here we investigate directly the effect of the JM domain on unliganded dimer stability of FGFR3, a receptor that is critically important for skeletal development. The data suggest that FGFR3 unliganded dimers are stabilized by receptor-receptor contacts that involve the JM domains. The contribution is significant, as it is similar in magnitude to the stabilizing contribution of a pathogenic mutation and the repulsive contribution of the extracellular domain. Furthermore, we show that the effects of the JM domain and a TM pathogenic mutation on unliganded FGFR3 dimer stability are additive. We observe that the JM-mediated dimer stabilization occurs when the JM domain is linked to FGFR3 TM domain and not simply anchored to the plasma membrane. These results point to a coordinated stabilization of the unliganded dimeric state of FGFR3 by its JM and TM domains via a mechanism that is distinctly different from the case of another well studied receptor, EGFR. Copyright © 2015. Published by Elsevier Ltd.
    Journal of Molecular Biology 02/2015; 427(8). DOI:10.1016/j.jmb.2015.02.013 · 3.96 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Here, we study the homodimerization of the transmembrane domain of Neu, as well as an oncogenic mutant (V664E), in vesicles derived from the plasma membrane of mammalian cells. For the characterization, we use a Fӧrster resonance energy transfer (FRET)-based method termed Quantitative Imaging-FRET (QI-FRET), which yields the donor and acceptor concentrations in addition to the FRET efficiencies in individual plasma membrane-derived vesicles. Our results demonstrate that both the wild-type and the mutant are 100% dimeric, suggesting that the Neu TM helix dimerizes more efficiently than other RTK TM domains in mammalian membranes. Furthermore, the data suggest that the V664E mutation causes a very small, but statistically significant change in dimer structure. This article is part of a Special Issue entitled: Interfacially active peptides and proteins.
    Biochimica et Biophysica Acta 03/2014; DOI:10.1016/j.bbamem.2014.03.001 · 4.66 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Membrane protein interactions, which underlie biological function, take place in the complex cellular membrane environment. Plasma membrane derived vesicles are a model system which allows the interactions between membrane proteins to be studied without the need for their extraction, purification, and reconstitution into lipid bilayers. Plasma membrane vesicles can be produced from different cell lines and by different methods, providing a rich variety of native-like model systems. With these choices, however, questions arise as to how the different types of vesicle preparations affect the interactions between membrane proteins. Here we address this question using the glycophorin A transmembrane domain (GpA) as a model system. We compare the dimerization of GpA in six different vesicle preparations derived from CHO, HEK 293T and A431 cells. We accomplish this with the use of a FRET-based method which yields the FRET efficiency, the donor concentration, and the acceptor concentration in each vesicle. We show that the vesicle preparation protocol has no statistically significant effect on GpA dimerization. Based on these results, we propose that any of six the plasma membrane preparations investigated here can be used as a model system for studies of membrane protein interactions.
    Biochimica et Biophysica Acta 04/2013; 1828(8). DOI:10.1016/j.bbamem.2013.03.022 · 4.66 Impact Factor


1 Download
Available from