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Chemical Inactivation of the E3 Ubiquitin Ligase Cereblon by Pomalidomide-based Homo-PROTACs
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Published on: May 15, 2019

Epoxomicin, a potent and selective proteasome inhibitor, exhibits in vivo antiinflammatory activity

L Meng1, R Mohan, B H Kwok

  • 1Department of Molecular, Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT 06520-8103, USA.

Proceedings of the National Academy of Sciences of the United States of America
|September 1, 1999
PubMed

Insights

Epoxomicin, a natural product, is a potent proteasome inhibitor that targets specific catalytic subunits. It selectively inhibits chymotrypsin-like activity, offering a novel tool for research.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Pharmacology

Background:

  • The proteasome is a crucial cellular machine regulating diverse processes, including cell cycle and NF-kappaB activation.
  • Understanding proteasome function is key to developing targeted therapies for various diseases.

Purpose of the Study:

  • To investigate the mechanism of action of the natural product epoxomicin as a proteasome inhibitor.
  • To characterize the specificity and potency of epoxomicin against proteasome catalytic subunits and activities.

Main Methods:

  • Utilized biotinylated-epoxomicin as a molecular probe to identify binding sites.
  • Performed enzymatic analyses on purified proteasome to determine inhibition kinetics.
  • Assessed inhibition of NF-kappaB activation in vitro and inflammation in vivo.

Main Results:

  • Epoxomicin covalently binds to LMP7, X, MECL1, and Z catalytic subunits of the proteasome.
  • It potently inhibits chymotrypsin-like activity, with weaker inhibition of trypsin-like and peptidyl-glutamyl peptide hydrolyzing activities.
  • Epoxomicin shows higher potency than lactacystin and NLVS, does not inhibit non-proteasomal proteases, and blocks NF-kappaB activation and in vivo inflammation.

Conclusions:

  • Epoxomicin is a novel, potent, and selective proteasome inhibitor.
  • Its unique properties make it a valuable tool for studying proteasome roles in biological systems.
  • Epoxomicin demonstrates potential for therapeutic applications targeting proteasome-mediated pathways.

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