Assessment of cardiac proteome dynamics with heavy water: Slower protein synthesis rates in interfibrillar than subsarcolemmal mitochondria

Takhar Kasumov, Erinne R. Dabkowski, Kadambari Chandra Shekar, Ling Li, Rogerio F. Ribeiro, Kenneth Walsh, Stephen F. Previs, Rovshan G. Sadygov, Belinda Willard, William C. Stanley

Research output: Contribution to journalArticle

44 Scopus citations

Abstract

Traditional proteomics provides static assessment of protein content, but not synthetic rates. Recently, proteome dynamics with heavy water (2H2O) was introduced, where 2H labels amino acids that are incorporated into proteins, and the synthesis rate of individual proteins is calculated using mass isotopomer distribution analysis. We refine this approach with a novel algorithm and rigorous selection criteria that improve the accuracy and precision of the calculation of synthesis rates and use it to measure protein kinetics in spatially distinct cardiac mitochondrial subpopulations. Subsarcolemmal mitochondria (SSM) and interfibrillar mitochondria (IFM) were isolated from adult rats, which were given 2H2O in the drinking water for up to 60 days. Plasma 2H2O and myocardial 2H-enrichment of amino acids were stable throughout the experimental protocol. Multiple tryptic peptides were identified from 28 proteins in both SSM and IFM and showed a time-dependent increase in heavy mass isotopomers that was consistent within a given protein. Mitochondrial protein synthesis was relatively slow (average half-life of 30 days, 2.4% per day). Although the synthesis rates for individual proteins were correlated between IFM and SSM (R2 = 0.84; P < 0.0001), values in IFM were 15% less than SSM (P < 0.001). In conclusion, administration of 2H2O results in stable enrichment of the cardiac precursor amino acid pool, with the use of refined analytical and computational methods coupled with cell fractionation one can measure synthesis rates for cardiac proteins in subcellular compartments in vivo, and protein synthesis is slower in mitochondria located among the myofibrils than in the subsarcolemmal region.

Original languageEnglish (US)
Pages (from-to)H1201-H1214
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume304
Issue number9
DOIs
StatePublished - 2013

Keywords

  • Deuterium
  • Heart
  • Heavy water
  • High resolution mass spectroscopy
  • Proteome dynamics
  • Proteomics

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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