Structural Basis for the Inhibitory Effects of Ubistatins in the Ubiquitin-Proteasome Pathway

TY - JOUR

T1 - Structural Basis for the Inhibitory Effects of Ubistatins in the Ubiquitin-Proteasome Pathway

AU - Nakasone, Mark A.

AU - Lewis, Timothy A.

AU - Walker, Olivier

AU - Thakur, Anita

AU - Mansour, Wissam

AU - Castañeda, Carlos A.

AU - Goeckeler-Fried, Jennifer L.

AU - Parlati, Frank

AU - Chou, Tsui-Fen

AU - Hayat, Ortal

AU - Zhang, Daoning

AU - Camara, Christina M.

AU - Bonn, Steven M.

AU - Nowicka, Urszula K.

AU - Krueger, Susan

AU - Glickman, Michael H.

AU - Brodsky, Jeffrey L.

AU - Deshaies, Raymond J.

AU - Fushman, David

N1 - Funding for this research was provided by: NCI NIH (GM065334, GM095755, GM075061, DK079307) ISF (909-14) Cystic Fibrosis Foundation Therapeutics (BRODSK13XXO) NSF (DBI1040158) Copyright © 2017 Elsevier Ltd. All rights reserved.

PY - 2017/12/5

Y1 - 2017/12/5

N2 - The discovery of ubistatins, small molecules that impair proteasomal degradation of proteins by directly binding to polyubiquitin, makes ubiquitin itself a potential therapeutic target. Although ubistatins have the potential for drug development and clinical applications, the lack of structural details of ubiquitin-ubistatin interactions has impeded their development. Here, we characterized a panel of new ubistatin derivatives using functional and binding assays. The structures of ubiquitin complexes with ubistatin B and hemi-ubistatin revealed direct interactions with ubiquitin's hydrophobic surface patch and the basic/polar residues surrounding it. Ubistatin B binds ubiquitin and diubiquitin tighter than a high-affinity ubiquitin receptor and shows strong preference for K48 linkages over K11 and K63. Furthermore, ubistatin B shields ubiquitin conjugates from disassembly by a range of deubiquitinases and by the 26S proteasome. Finally, ubistatin B penetrates cancer cells and alters the cellular ubiquitin landscape. These findings highlight versatile properties of ubistatins and have implications for their future development and use in targeting ubiquitin-signaling pathways.

AB - The discovery of ubistatins, small molecules that impair proteasomal degradation of proteins by directly binding to polyubiquitin, makes ubiquitin itself a potential therapeutic target. Although ubistatins have the potential for drug development and clinical applications, the lack of structural details of ubiquitin-ubistatin interactions has impeded their development. Here, we characterized a panel of new ubistatin derivatives using functional and binding assays. The structures of ubiquitin complexes with ubistatin B and hemi-ubistatin revealed direct interactions with ubiquitin's hydrophobic surface patch and the basic/polar residues surrounding it. Ubistatin B binds ubiquitin and diubiquitin tighter than a high-affinity ubiquitin receptor and shows strong preference for K48 linkages over K11 and K63. Furthermore, ubistatin B shields ubiquitin conjugates from disassembly by a range of deubiquitinases and by the 26S proteasome. Finally, ubistatin B penetrates cancer cells and alters the cellular ubiquitin landscape. These findings highlight versatile properties of ubistatins and have implications for their future development and use in targeting ubiquitin-signaling pathways.

KW - Binding Sites

KW - Cell Line

KW - HeLa Cells

KW - Humans

KW - Molecular Docking Simulation

KW - Proteasome Endopeptidase Complex/chemistry

KW - Protein Binding

KW - Quinolines/chemistry

KW - Saccharomyces cerevisiae/enzymology

KW - Sulfanilic Acids/chemistry

KW - Ubiquitins/antagonists & inhibitors

U2 - 10.1016/j.str.2017.10.007

DO - 10.1016/j.str.2017.10.007

M3 - Article

C2 - 29153505

SN - 0969-2126

VL - 25

SP - 1839-1855.e11

JO - Structure

JF - Structure

IS - 12

ER -