title: Assessment of cardiac proteome dynamics with heavy water: slower protein synthesis rates in interfibrillar than subsarcolemmal mitochondria.
abstract: Traditional proteomics provides static assessment of protein content, but not synthetic rates. Recently, proteome dynamics with heavy water ((2)H2O) was introduced, where (2)H 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 (2)H2O in the drinking water for up to 60 days. Plasma (2)H2O and myocardial (2)H-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 (R(2) = 0.84; P < 0.0001), values in IFM were 15% less than SSM (P < 0.001). In conclusion, administration of (2)H2O 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.
authors: Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, Ohio 44195, USA. kasumot@ccf.org
authors: Takhar
authors: T
authors: Kasumov
authors: Erinne R
authors: ER
authors: Dabkowski
authors: Kadambari Chandra
authors: KC
authors: Shekar
authors: Ling
authors: L
authors: Li
authors: Rogerio F
authors: RF
authors: Ribeiro
authors: Kenneth
authors: K
authors: Walsh
authors: Stephen F
authors: SF
authors: Previs
authors: Rovshan G
authors: RG
authors: Sadygov
authors: Belinda
authors: B
authors: Willard
authors: William C
authors: WC
authors: Stanley
mesh_terms: D000818:Animals; D003593:Cytoplasm; D017666:Deuterium Oxide; D008297:Male; D013058:Mass Spectrometry; D008929:Mitochondria, Heart / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D014176:Protein Biosynthesis; D020543:Proteome / Q000032:analysis / Q000378:metabolism*; D011849:Radioactive Tracers; D051381:Rats; D017207:Rats, Sprague-Dawley; D012508:Sarcolemma
chemical_list: D020543:Proteome; D011849:Radioactive Tracers; D017666:Deuterium Oxide
keywords: deuterium; heart; heavy water; high resolution mass spectroscopy; proteome dynamics; proteomics