Long-range allosteric regulation of the human 26S proteasome by 20S proteasome-targeting cancer drugs

Nat Commun. 2017 May 25:8:15578. doi: 10.1038/ncomms15578.

Abstract

The proteasome holoenzyme is the major non-lysosomal protease; its proteolytic activity is essential for cellular homeostasis. Thus, it is an attractive target for the development of chemotherapeutics. While the structural basis of core particle (CP) inhibitors is largely understood, their structural impact on the proteasome holoenzyme remains entirely elusive. Here, we determined the structure of the 26S proteasome with and without the inhibitor Oprozomib. Drug binding modifies the energy landscape of conformational motion in the proteasome regulatory particle (RP). Structurally, the energy barrier created by Oprozomib triggers a long-range allosteric regulation, resulting in the stabilization of a non-productive state. Thereby, the chemical drug-binding signal is converted, propagated and amplified into structural changes over a distance of more than 150 Å from the proteolytic site to the ubiquitin receptor Rpn10. The direct visualization of changes in conformational dynamics upon drug binding allows new ways to screen and develop future allosteric proteasome inhibitors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / metabolism*
  • Cell Line, Tumor
  • Cryoelectron Microscopy
  • HeLa Cells
  • Humans
  • Models, Molecular
  • Oligopeptides / metabolism*
  • Proteasome Endopeptidase Complex / drug effects*
  • Proteasome Endopeptidase Complex / metabolism*
  • Proteasome Inhibitors / metabolism*
  • Protein Binding
  • Protein Structure, Tertiary

Substances

  • Antineoplastic Agents
  • ONX 0912
  • Oligopeptides
  • Proteasome Inhibitors
  • Proteasome Endopeptidase Complex
  • ATP dependent 26S protease