Report
Teaser, summary, work performed and final results
Periodic Reporting for period 2 - EPITOOLS (Chemical biology approaches to unraveling the histone code)
Teaser
Posttranslational modifications on histones play crucial roles in the epigenetic regulation of eukaryotic gene expression. Chemical modifications that occur on histone tails include acetylation, methylation,phosphorylation, ubiquitination, and SUMOylation. This chemical...
Summary
Posttranslational modifications on histones play crucial roles in the epigenetic regulation of eukaryotic gene expression. Chemical modifications that occur on histone tails include acetylation, methylation,
phosphorylation, ubiquitination, and SUMOylation. This chemical diversity together with the positions and combinations of these modifications give rise to complex networks of highly controlled gene expression
programs. The identification and characterisation of chromatin-associated proteins (or epigenetic regulators) in recent years has advanced our understanding of the significance of these histone modifications and the regulatory outcomes in development and in disease. The project aims to generate new classes of highly selective and potent chemical probes for epigenetic regulators, focusing on enzymes and proteins associated with methyl-lysine marks. A novel modified peptide-based discovery platform, which combines molecular, chemical, biophysical and cellular techniques, will be developed and applied. These chemical probes will be useful for biological and biomedical research, and will serve as potential starting points for therapeutic epigenetic intervention.
Work performed
We have successfully generated macrocyclic peptide probes for histone demethylase KDM4 subfamily. Cell activity of the peptides was optimised via systematic structure- and mass spectrometry guided design. The probes have been widely distributed for cellular testing in the context of multiple diseases. Work towards understanding peptide features for cell-permeability has been made, with preliminary data emerging. Further we have made important progress in targeting other \'challenging\' epigenetic protein targets, such as the methyl lysine reader domains, and have identified potent peptide ligands which have been used as tools for mechanistic and kinetic studies. High affinity cyclic peptide-based tools have also been developed as reagents complementary to antibodies for studying target proteins and protein-protein complexes in cellular context.
Final results
Our work to date have exemplified the use of diverse peptide-based approaches for studying epigenetic regulation. We have generated cyclic peptide probes that inhibit the histone demethylases via catalytic domains or allosteric sites, with unprecedented high affinity and selectivity.These probes are currently being tested in biological assays in multiple disease context with collaborators. We hope these probes / tools will be useful in target validation, as well as to enable future design of epigenetic-targeted therapeutics.