Synthesis of Organelle-Specific Inhibitors of Deubiquitinating Enzymes

  • Heidi Korsberg

Student thesis: Master of Philosophy

Abstract

ABSTRACTIn virtually all cellular processes, proteins undergo post-translational modification by the conjugation of the protein ubiquitin, which is a reversible process owing to deubiquitinating enzymes (DUBs). The possibility of conjugating additional ubiquitin moieties to either the protein itself or internal lysine residues on ubiquitin, affords different ubiquitin modifications to be built up. These modifications are recognized as different signals in the cell, hence the ubiquitin signal governs the fate and function of the protein substrate. The signal can also be edited or removed by DUBs, which is a highly understudied class of enzymes, although linked to numerous diseases. Inhibition of DUBs have shown promising anti-cancer abilities, where a prostaglandin pharmacophore (P4F) is well established. The Whitehead and Swanton groups developed a synthesis for the documented DUB inhibitor Eeyarestatin I (ES1), and showed that the western domain of the compound targets the ER, but possesses no biological activity in its own right. The aim of the project was to synthesise a new ER targeted DUB inhibitor by coupling the ESI western domain with P4F, in addition to synthesising an additional separate DUB inhibitor by coupling the same pharmacophore to a long chain alkyl phosphonium salt, which is known to target mitochondria. Both inhibitors and the respective targeting domains were subjected to biochemical analysis in order to assess their ability to induce polyubiquitinated material at different concentrations, which resulted in both inhibitors showing some extent of polyubiquitin-accumulative abilities. Cell viability assays with increasing concentrations of the inhibitors and the mitochondrial targeting domain were also carried out, where cell viability was shown to decrease with increasing concentrations of the inhibitors, but to be relatively unaffected by the targeting domain.
Date of Award1 Aug 2015
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorRoger Whitehead (Supervisor) & Eileithyia Swanton (Supervisor)

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