1. Structure-guided bifunctional molecules hit a DEUBAD-lacking hRpn13 species upregulated in multiple myeloma
- Author
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Charles D. Schwieters, Xiuxiu Lu, Vasty Osei-Amponsa, Julianna C. King, Thorkell Andresson, Caroline Fromont, Rolf E. Swenson, Bao Tran, Xiang Chen, Kylie J. Walters, Yongmei Zhao, Nadya I. Tarasova, Hiroshi Matsuo, Marzena A. Dyba, Sulbha Choudhari, Raj Chari, Venkata R. Sabbasani, Sergey G. Tarasov, Christine N. Evans, and King C. Chan
- Subjects
biology ,medicine.diagnostic_test ,Chemistry ,In silico ,Proteolysis ,Cell ,Deubiquitinating enzyme ,Cell biology ,medicine.anatomical_structure ,Proteasome ,Downregulation and upregulation ,Ubiquitin ,biology.protein ,medicine ,Receptor - Abstract
Proteasome substrate receptor hRpn13 is a promising anti-cancer target. By integrated in silico and biophysical screening, we identified a chemical scaffold that binds hRpn13 with non-covalent interactions that mimic the proteasome and a weak electrophile for Michael addition. hRpn13 Pru domain binds proteasomes and ubiquitin whereas its DEUBAD domain binds deubiquitinating enzyme UCHL5. NMR revealed lead compound XL5 to interdigitate into a hydrophobic pocket created by lateral movement of a Pru β-hairpin with an exposed end for Proteolysis Targeting Chimeras (PROTACs). Implementing XL5-PROTACs as chemical probes identified a DEUBAD-lacking hRpn13 species (hRpn13Pru) present naturally with cell type-dependent abundance. XL5-PROTACs preferentially target hRpn13Pru, causing its ubiquitination. Gene-editing and rescue experiments established hRpn13 requirement for XL5-PROTAC-triggered apoptosis and increased p62 levels. These data establish hRpn13 as an anti-cancer target for multiple myeloma and introduce an hRpn13-targeting scaffold that can be optimized for preclinical trials against hRpn13Pru-producing cancer types.
- Published
- 2021
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