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Published on: April 5, 2015
Identification of TRIO-GEFD1 chemical inhibitors using the yeast exchange assay
Anne Blangy1, Nathalie Bouquier, Cécile Gauthier-Rouvière
1Centre de Recherches en Biochimie Macromoléculaire, CNRS (Centre National de la Recherche Scientifique) FRE2593, 1919 route de Mende, 34293 Montpellier Cedex 5, France. anne.blangy@crbm.cnrs.fr
Background Information:
Rho GTPases are involved in many biological processes and participate in cancer development. Their activation is catalysed by exchange factors [RhoGEFs (Rho GTPase guanine nucleotide-exchange factor)] of the Dbl family. RhoGEFs display proto-oncogenic features, thus appearing as candidate targets for anticancer drugs. Dominant-negative Rho GTPase mutants have been widely used to block RhoGEF signalling. However, these tools suffer from limitations, due to the high number of RhoGEFs and the complex mechanisms that control Rho GTPase activation.
Results:
RhoG-T17N is a poor inhibitor of its exchange factor TRIO-GEFD1 (first exchange domain of the exchange factor TRIO) in vivo: although it binds to TRIO-GEFD1, RhoG-T17N does not block the downstream signalling. Using the yeast exchange assay, we show that in the presence of TRIO-GEFD1, RhoG-T17N can bind to its effectors, which illustrates how negative mutants may produce misleading interpretations and emphasizes the need for new types of RhoGEF inhibitors. In that prospect, we adapted the yeast exchange assay method to identify RhoGEF inhibitors. Using this novel approach, we screened a 3500-chemical-compound library and identified a potential inhibitor of TRIO-GEFD1. This molecule inhibited TRIO-GEFD1 in vitro. Among the chemical analogues of this compound, we identified two molecules with better inhibitory activity. The three TRIO-GEFD1 inhibitors had no effect on ARHGEF17 and ARNO [ARF (ADP-ribosylation factor) nucleotide-binding-site opener], two exchange factors for RhoA and Arf1 respectively.
Conclusions:
The development of RhoGEF inhibitors appears as a valuable tool for the study of Rho GTPase signalling pathways. The yeast exchange assay adaptation we present here is suitable to screen for chemical or peptide libraries and identify candidate inhibitors.
Insights
Researchers developed a new yeast exchange assay to identify RhoGEF inhibitors, crucial for studying Rho GTPase signaling in cancer. This method successfully screened compounds, finding specific inhibitors for TRIO-GEFD1 without affecting other related proteins.
Area of Science:
- Molecular Biology
- Biochemistry
- Cancer Research
Background:
- Rho GTPases are key regulators of cellular processes and implicated in cancer development.
- RhoGEFs (Rho GTPase guanine nucleotide-exchange factor) activate Rho GTPases and are potential anticancer drug targets.
- Existing dominant-negative Rho GTPase mutants have limitations for studying RhoGEF signaling due to the complexity and number of RhoGEFs.
Purpose of the Study:
- To develop and validate a novel method for identifying RhoGEF inhibitors.
- To investigate the limitations of dominant-negative Rho GTPase mutants.
- To discover specific inhibitors of the RhoGEF TRIO-GEFD1.
Main Methods:
- Adaptation of the yeast exchange assay to screen for RhoGEF inhibitors.
- Screening of a 3500-chemical-compound library.
- In vitro inhibition assays to validate identified compounds.
Main Results:
- Dominant-negative RhoG-T17N mutant showed poor inhibition of TRIO-GEFD1 in vivo, highlighting potential misinterpretations.
- The adapted yeast exchange assay successfully identified a TRIO-GEFD1 inhibitor from a chemical library.
- Identified inhibitors demonstrated specificity, affecting TRIO-GEFD1 but not ARHGEF17 or ARNO.
Conclusions:
- The adapted yeast exchange assay is a valuable tool for screening chemical or peptide libraries to identify RhoGEF inhibitors.
- Development of RhoGEF inhibitors is a promising strategy for studying Rho GTPase signaling pathways.
- This approach aids in discovering targeted inhibitors for potential cancer therapies.
