S-Nitrosylation of Sarcomeric Proteins Depresses Myofilament Ca2+ Sensitivity in Intact Cardiomyocytes

Cicero Figueiredo-Freitas, Raul A. Dulce, Matthew W. Foster, Jingsheng Liang, Aline M.S. Yamashita, Frederico L. Lima-Rosa, J. Will Thompson, M. Arthur Moseley, Joshua M. Hare, Leonardo Nogueira, Martha M. Sorenson, Jose Renato Pinto

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

The heart responds to physiological and pathophysiological stress factors by increasing its production of nitric oxide (NO), which reacts with intracellular glutathione to form S-nitrosoglutathione (GSNO), a protein S-nitrosylating agent. Although S-nitrosylation protects some cardiac proteins against oxidative stress, direct effects on myofilament performance are unknown. We hypothesize that S-nitrosylation of sarcomeric proteins will modulate the performance of cardiac myofilaments. Results: Incubation of intact mouse cardiomyocytes with S-nitrosocysteine (CysNO, a cell-permeable low-molecular-weight nitrosothiol) significantly decreased myofilament Ca2+ sensitivity. In demembranated (skinned) fibers, S-nitrosylation with 1 μM GSNO also decreased Ca2+ sensitivity of contraction and 10 μM reduced maximal isometric force, while inhibition of relaxation and myofibrillar ATPase required higher concentrations (≥100 μM). Reducing S-nitrosylation with ascorbate partially reversed the effects on Ca2+ sensitivity and ATPase activity. In live cardiomyocytes treated with CysNO, resin-assisted capture of S-nitrosylated protein thiols was combined with label-free liquid chromatography-tandem mass spectrometry to quantify S-nitrosylation and determine the susceptible cysteine sites on myosin, actin, myosin-binding protein C, troponin C and I, tropomyosin, and titin. The ability of sarcomere proteins to form S-NO from 10-500 μM CysNO in intact cardiomyocytes was further determined by immunoblot, with actin, myosin, myosin-binding protein C, and troponin C being the more susceptible sarcomeric proteins. Innovation and Conclusions: Thus, specific physiological effects are associated with S-nitrosylation of a limited number of cysteine residues in sarcomeric proteins, which also offer potential targets for interventions in pathophysiological situations. Antioxid. Redox Signal. 23, 1017-1034.

Original languageEnglish (US)
Pages (from-to)1017-1034
Number of pages18
JournalAntioxidants and Redox Signaling
Volume23
Issue number13
DOIs
StatePublished - Nov 1 2015

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Molecular Biology
  • Clinical Biochemistry
  • Cell Biology

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