%0 Journal Article %J Cell Chem Biol %D 2021 %T Target identification for small-molecule discovery in the FOXO3a tumor-suppressor pathway using a biodiverse peptide library. %A Emery, Amy %A Hardwick, Bryn S %A Crooks, Alex T %A Milech, Nadia %A Watt, Paul M %A Mithra, Chandan %A Kumar, Vikrant %A Giridharan, Saranya %A Sadasivam, Gayathri %A Mathivanan, Subashini %A Sudhakar, Sneha %A Bairy, Sneha %A Bharatham, Kavitha %A Hurakadli, Manjunath A %A Prasad, Thazhe K %A Kamariah, Neelagandan %A Muellner, Markus %A Coelho, Miguel %A Torrance, Christopher J %A McKenzie, Grahame J %A Venkitaraman, Ashok R %X

Genetic screening technologies to identify and validate macromolecular interactions (MMIs) essential for complex pathways remain an important unmet need for systems biology and therapeutics development. Here, we use a library of peptides from diverse prokaryal genomes to screen MMIs promoting the nuclear relocalization of Forkhead Box O3 (FOXO3a), a tumor suppressor more frequently inactivated by post-translational modification than mutation. A hit peptide engages the 14-3-3 family of signal regulators through a phosphorylation-dependent interaction, modulates FOXO3a-mediated transcription, and suppresses cancer cell growth. In a crystal structure, the hit peptide occupies the phosphopeptide-binding groove of 14-3-3ε in a conformation distinct from its natural peptide substrates. A biophysical screen identifies drug-like small molecules that displace the hit peptide from 14-3-3ε, providing starting points for structure-guided development. Our findings exemplify "protein interference," an approach using evolutionarily diverse, natural peptides to rapidly identify, validate, and develop chemical probes against MMIs essential for complex cellular phenotypes.

%B Cell Chem Biol %8 2021 Jun 01 %G eng %R 10.1016/j.chembiol.2021.05.009