Rapaprotin, an Endopeptidase‐Activated Proteasome Inhibitor that Induces 26S Disassembly
Abstract
Abstract The 19S regulatory particle (RP) associates with the 20S core particle (CP) to form the 26S proteasome, an evolutionarily conserved holoenzyme that plays key roles in both physiological and pathological processes. Proteasome inhibitors that target the catalytic subunits within the 20S have proven to be valuable research tools and therapeutics for various cancers. Herein we report the discovery of rapaprotin, a 26S proteasome assembly inhibitor from our natural product‐inspired hybrid macrocycle rapafucin library. Rapaprotin induces apoptosis in both myeloma and leukemia cell lines. Genome‐wide CRISPR‐Cas9 screen identified a cytosolic enzyme, prolyl endopeptidase (PREP) that is required for the pro‐apoptotic activity of rapaprotin. Further mechanistic studies revealed that rapaprotin acts as a molecular transformer, changing from an inactive cyclic form into an active linear form, rapaprotin‐L, upon PREP cleavage, to block 26S proteasome activity. Time‐resolved cryogenic electron microscopy (cryo‐EM) revealed that rapaprotin‐L induces dissociation of the 19S RP from the 26S holoenzyme, which was verified in cells. Furthermore, rapaprotin exhibits a marked synergistic effect with FDA‐approved proteasome inhibitors and resensitizes drug‐resistant multiple myeloma cells from patients to bortezomib. Taken together, these results suggest that rapaprotin is a new chemical tool to probe the dynamics of the 26S proteasome assembly and a promising anticancer drug lead.
Article Details
Authors (21)
Hanjing Peng
Department of Pharmacology and Molecular Sciences Johns Hopkins School of Medicine Baltimore MD 21205 USA
Zufeng Guo
Department of Pharmacology and Molecular Sciences Johns Hopkins School of Medicine Baltimore MD 21205 USA
Wei Li Wang
State Key Laboratory for Artificial Microstructures and Mesoscopic Physics Laboratory of Electron Microscopy School of Physics Peking University Beijing 100871 China
Deyao Yin
State Key Laboratory for Artificial Microstructures and Mesoscopic Physics Laboratory of Electron Microscopy School of Physics Peking University Beijing 100871 China
Shitao Zou
State Key Laboratory for Artificial Microstructures and Mesoscopic Physics Laboratory of Electron Microscopy School of Physics Peking University Beijing 100871 China
Thomas Asbell
Department of Pharmacology and Molecular Sciences Johns Hopkins School of Medicine Baltimore MD 21205 USA
Brett R. Ullman
Rapafusyn Pharmaceuticals Baltimore MD 21205 USA
Maya Thakar
Sidney Kimmel Comprehensive Cancer Center Johns Hopkins School of Medicine Baltimore MD 21287 USA
Feiran Zhang
Department of Chemistry, Mechanical Engineering and School of Biomedical Sciences, The University of Hong Kong
Sam Y. Hong
Rapafusyn Pharmaceuticals Baltimore MD 21205 USA
A. V. Subba Rao
Department of Pharmacology and Molecular Sciences Johns Hopkins School of Medicine Baltimore MD 21205 USA
Kunyu Wang
Shuwen Zhang
Zhaolong Wu
Xuemei Li
RIKEN Center for Brain Science
Aidan A. Kendra
Department of Pharmacology and Molecular Sciences Johns Hopkins School of Medicine Baltimore MD 21205 USA
Seth S. Margolis
Solomon H. Snyder Department of Neuroscience Johns Hopkins School of Medicine Baltimore MD 21205 USA
William H. Matsui
Sidney Kimmel Comprehensive Cancer Center Johns Hopkins School of Medicine Baltimore MD 21287 USA
Christian B. Gocke
Sidney Kimmel Comprehensive Cancer Center Johns Hopkins School of Medicine Baltimore MD 21287 USA
Youdong Mao
Jun O. Liu