The regulatory significance of tag recycling in the mycobacterial Pup-proteasome system

Yifat Elharar, Shai Schlussel, Nir Hecht, Michael M. Meijler, Eyal Gur

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Pup, a ubiquitin analog, tags proteins for degradation by the bacterial proteasome. As an intracellular proteolytic system, the Pup-proteasome system (PPS) must be carefully regulated to prevent excessive protein degradation. Currently, those factors underlying PPS regulation remain poorly understood. Here, experimental analysis combined with theoretical modeling of in vivo protein pupylation revealed how the basic PPS design allows stable and controlled protein pupylation. Specifically, the recycling of Pup when targets are degraded allows the PPS to maintain steady-state levels of protein pupylation and degradation at a rate limited by proteasome function, and at a pupylome level limited by Pup concentrations. This design allows the Pup-ligase, a highly promiscuous enzyme, to act in a controlled manner without causing damage, and the PPS to be effectively tuned to control protein degradation. This study thus provides understanding of how the inherent design of an intracellular proteolytic system serves crucial regulatory purposes.

Original languageEnglish
Pages (from-to)1804-1814
Number of pages11
JournalFEBS Journal
Issue number12
StatePublished - 1 Jun 2017


  • Dop
  • PafA
  • Pup
  • proteasome
  • proteolysis

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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