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Regulation of feedback between protein kinase A and the proteasome system worsens Huntington's disease

Jiun-Tsai Lin1, Wei-Cheng Chang, Hui-Mei Chen

  • 1Institute of Biomedical Sciences, Academia Sinica, Nankang, Taipei, Taiwan.

Molecular and Cellular Biology
|January 1, 2013
PubMed

Insights

Huntington's disease involves impaired proteasome function, leading to reduced protein kinase A (PKA) activity. Restoring PKA activity can improve proteasome function and decrease harmful protein aggregates in Huntington's disease.

Area of Science:

  • Neurobiology
  • Molecular Biology
  • Genetics

Background:

  • Huntington's disease (HD) is a neurodegenerative disorder linked to CAG repeat expansion in the Huntingtin (HTT) gene.
  • Dysregulation of the cyclic AMP (cAMP)/protein kinase A (PKA) pathway is observed in HD progression.

Purpose of the Study:

  • To investigate the relationship between PKA activity and proteasome function in Huntington's disease.
  • To explore the therapeutic potential of modulating the PKA-proteasome pathway in HD.

Main Methods:

  • Utilized two HD mouse models (R6/2 and N171-82Q) and mutant HTT (mHTT)-expressing striatal cells.
  • Assessed PKA activity, proteasome function, and levels of PKA regulatory subunits (PKA-Rs).
  • Employed dominant-negative and phosphomimetic Rpt6 mutants to study proteasome regulation.

Main Results:

  • Lower PKA activity correlated with proteasome impairment in HD models.
  • Mutant HTT caused proteasome impairment, leading to PKA-R accumulation and reduced PKA activity.
  • PKA activation rescued proteasome activity, reduced mHTT aggregates, and improved motor function in Rpt6 mutant models.

Conclusions:

  • A positive feedback loop between PKA and the proteasome is crucial for Huntington's disease pathogenesis.
  • Targeting the PKA-proteasome pathway offers a potential therapeutic strategy for HD.

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