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Updated: Jun 20, 2026

Comparing the Affinity of GTPase-binding Proteins using Competition Assays
Published on: October 8, 2015
Structure-activity relationship of isoform selective inhibitors of Rac1/1b GTPase nucleotide binding
Eric Beausoleil1, Cédric Chauvignac, Thierry Taverne
1Exonhit Therapeutics, 65 Boulevard Massena, F-75013 Paris, France. eric.beausoleil@exonhit.com
Abstract:
The synthesis of a series of berberine, phenantridine and isoquinoline derivatives was realized to explore their Rho GTPase nucleotide inhibitory activity. The compounds were evaluated in a nucleotide binding competition assay against Rac1, Rac1b, Cdc42 and in a cellular Rac GTPase activation assay. The insertion of 19 AA in the splice variant Rac1b is shown to be sufficient to introduce a conformational difference that allows compounds 4, 21, 22, and 26 to exhibit selective inhibition of Rac 1b over Rac1.
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