Molecular mechanisms of proteasome plasticity in aging

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28 Scopus citations

Abstract

The ubiquitin-proteasome pathway plays a crucial role in regulation of intracellular protein turnover. Proteasome, the central protease of the pathway, encompasses multi-subunit assemblies sharing a common catalytic core supplemented by regulatory modules and localizing to different subcellular compartments. To better comprehend age-related functions of the proteasome we surveyed content, composition and catalytic properties of the enzyme in cytosolic, microsomal and nuclear fractions obtained from mouse livers subjected to organismal aging. We found that during aging subunit composition and subcellular distribution of proteasomes changed without substantial alterations in the total level of core complexes. We observed that the general decline in proteasomes functions was limited to nuclear and cytosolic compartments. Surprisingly, the observed changes in activity and specificity were linked to the amount of the activator module and distinct composition of the catalytic subunits. In contrast, activity, specificity and composition of the microsomal-associated proteasomes remained mostly unaffected by aging; however their relative contribution to the total activity was substantially elevated. Unexpectedly, the nuclear proteasomes were affected most profoundly by aging possibly triggering significant changes in cellular signaling and transcription. Collectively, the data indicate an age-related refocusing of proteasome from the compartment-specific functions towards general protein maintenance.

Original languageEnglish (US)
Pages (from-to)144-155
Number of pages12
JournalMechanisms of Ageing and Development
Volume131
Issue number2
DOIs
StatePublished - Feb 1 2010

Keywords

  • Aging
  • Compartmentalization
  • Liver
  • Mouse
  • Proteasome

ASJC Scopus subject areas

  • Aging
  • Developmental Biology

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