Differential regulation of proteasome function in isoproterenol-induced cardiac hypertrophy.

Journal Article (Journal Article)

RATIONALE: Proteasomal degradation is altered in many disease phenotypes including cardiac hypertrophy, a prevalent condition leading to heart failure. Our recent investigations identified heterogeneous subpopulations of proteasome complexes in the heart and implicated multiple mechanisms for their regulation. OBJECTIVE: The study aimed at identification of molecular mechanisms changing proteasome function in the hypertrophic heart. METHOD AND RESULTS: Proteasome function, expression, and assembly were analyzed during the development of cardiac hypertrophy induced by β-adrenergic stimulation. The analysis revealed, for the first time, divergent regulation of proteasome function in cardiac hypertrophy. Proteasome complexes have 3 different proteolytic activities, which are ATP-dependent for 26S complexes (19S assembled with 20S) and ATP-independent for 20S core particles. The 26S activities were enhanced in hypertrophic hearts, partially because of increased expression and assembly of 19S subunits with 20S core complexes. In contrast, caspase- and trypsin-like 20S activities were significantly decreased. Activation of endogenous cAMP-dependent protein kinase (PKA) rescued the depressed 20S functions, supporting the notion that PKA signaling is a positive regulator of protein degradation in the heart. Chymotrypsin-like 20S activity was stably maintained during cardiac remodeling, indicating a switch in proteasome subpopulations, which was supported by altered expression and incorporation of inducible β subunits. CONCLUSIONS: Three novel mechanisms for the regulation of proteasome activities were discovered in the development of cardiac hypertrophy: (1) increased incorporation of inducible subunits in 20S proteasomes; (2) enhanced 20S sensitivity to PKA activation; and (3) increased 26S assembly. PKA modulation of proteasome complexes may provide a novel therapeutic avenue for restoration of cardiac function in the diseased myocardium.

Full Text

Duke Authors

Cited Authors

  • Drews, O; Tsukamoto, O; Liem, D; Streicher, J; Wang, Y; Ping, P

Published Date

  • October 29, 2010

Published In

Volume / Issue

  • 107 / 9

Start / End Page

  • 1094 - 1101

PubMed ID

  • 20814020

Pubmed Central ID

  • PMC3360925

Electronic International Standard Serial Number (EISSN)

  • 1524-4571

Digital Object Identifier (DOI)

  • 10.1161/CIRCRESAHA.110.222364


  • eng

Conference Location

  • United States