Discovery of Stereoselective Targeted Covalent Inhibitors of the RAB27-Effector Protein-Protein Interaction.
6 affiliations
- 1Department of Chemistry, Imperial College London, LondonW12 0BZ, U.K.
- 2Centre for Molecular Cell Biology, Department of Biochemistry, School of Biological and Behavioural Sciences, Queen Mary University of London, LondonE1 4NS, U.K.
- 3Department of Life Sciences, Imperial College London, LondonW12 0BZ, U.K.
- 4School of Life Sciences, University of Nottingham, NottinghamNG7 2UH, U.K.
- 5ZoBio B.V., J.H. Oortweg 19, 2333 CHLeiden, Netherlands.
- 6National Heart & Lung Institute, Imperial College London, Hammersmith Campus, LondonW12 0NN, U.K.
Abstract
RAB27A and RAB27B are homologous small GTPases that regulate intracellular vesicle trafficking, orchestrating endocytic and exocytic processes that affect cellular communication, immune responses, and the dynamics of the cellular microenvironment. Through their interactions with effector proteins, RAB27A/B plays roles in tumor metastasis and chronic inflammation. However, pharmacological modulation of their activity faces challenges typical of small GTPases, including a lack of well-defined pockets outside the conserved GTP binding site and large RAB27-effector protein-protein interaction (PPI) surfaces. Here, we present the discovery and development of the first cell-active, rationally designed covalent inhibitors of the RAB27-effector interaction, targeting a non-conserved cysteine residue flanking the PPI interface. An electrophile-first biochemical screen led to a novel class of acrylamide covalent inhibitors, and X-ray crystallography structure-guided design led to optimized inhibitors and probes that enantioselectively target RAB27A/B Cys123 in cells. Potency and selectivity were confirmed through biochemical and cellular assays, including chemical proteomics and phenotype recapitulation in melanocytes, alongside a matched inactive enantioprobe control. In contrast, a previously reported compound, Nexinhib-20, was found to be cytotoxic and to exert its activity through non-selective reactivity. This work provides the first toolbox of cell-active chemical probes for RAB27 that can be used in future studies to shed light on the function of this protein and its potential as a therapeutic target.
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BibTeX
@article{vita2026discovery,
title = {{Discovery of Stereoselective Targeted Covalent Inhibitors of the RAB27-Effector Protein-Protein Interaction.}},
author = {Elena De Vita and Adam M Thomas and Delia Brustur and Montse Tersa and Rita Petracca and Shradda R Vadodaria and Deborah A Briggs and Jack W Houghton and Thomas Lanyon-Hogg and Gregory B Craven and R Marc L Morgan and Alan Armstrong and David J Mann and Katharine Lodge and Alistair N Hume and Ernesto Cota and Edward W Tate},
journal = {Journal of the American Chemical Society},
year = {2026},
month = sep,
doi = {10.1021/jacs.6c08927},
url = {https://europepmc.org/article/MED/42937809},
note = {CC BY},
}
RIS
TY - JOUR
TI - Discovery of Stereoselective Targeted Covalent Inhibitors of the RAB27-Effector Protein-Protein Interaction.
AU - Elena De Vita
AU - Adam M Thomas
AU - Delia Brustur
AU - Montse Tersa
AU - Rita Petracca
AU - Shradda R Vadodaria
AU - Deborah A Briggs
AU - Jack W Houghton
AU - Thomas Lanyon-Hogg
AU - Gregory B Craven
AU - R Marc L Morgan
AU - Alan Armstrong
AU - David J Mann
AU - Katharine Lodge
AU - Alistair N Hume
AU - Ernesto Cota
AU - Edward W Tate
PY - 2026
DA - 2026/09/01
JO - Journal of the American Chemical Society
DO - 10.1021/jacs.6c08927
UR - https://europepmc.org/article/MED/42937809
AB - RAB27A and RAB27B are homologous small GTPases that regulate intracellular vesicle trafficking, orchestrating endocytic and exocytic processes that affect cellular communication, immune responses, and the dynamics of the cellular microenvironment. Through their interactions with effector proteins, RAB27A/B plays roles in tumor metastasis and chronic inflammation. However, pharmacological modulation of their activity faces challenges typical of small GTPases, including a lack of well-defined pockets outside the conserved GTP binding site and large RAB27-effector protein-protein interaction (PPI) surfaces. Here, we present the discovery and development of the first cell-active, rationally designed covalent inhibitors of the RAB27-effector interaction, targeting a non-conserved cysteine residue flanking the PPI interface. An electrophile-first biochemical screen led to a novel class of acrylamide covalent inhibitors, and X-ray crystallography structure-guided design led to optimized inhibitors and probes that enantioselectively target RAB27A/B Cys123 in cells. Potency and selectivity were confirmed through biochemical and cellular assays, including chemical proteomics and phenotype recapitulation in melanocytes, alongside a matched inactive enantioprobe control. In contrast, a previously reported compound, Nexinhib-20, was found to be cytotoxic and to exert its activity through non-selective reactivity. This work provides the first toolbox of cell-active chemical probes for RAB27 that can be used in future studies to shed light on the function of this protein and its potential as a therapeutic target.
SN - 0002-7863
SN - 1520-5126
ER -