ArticleCirculation research2010
The C terminus of cardiac troponin I stabilizes the Ca2+-activated state of tropomyosin on actin filaments.
Article in Circulation research, 2010. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 52 papers.
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Who cites it
52 citing papers in PubMed, 68 citations in OpenAlex.
- cTnIR193H restrictive cardiomyopathy mice satisfy high-energy metabolic demands through regulating glucose metabolism.Genes & diseases · 2026Article
- The Structural Role of Tropomyosin in Regulating Thin Filament Activation of Actin-Myosin Interaction.Sub-cellular biochemistry · 2026Review
- Fluorescent protein tags for human tropomyosin isoform comparison.Biology open · 2025Article
- Resolving the structure and dynamics of the disordered C terminus of human cardiac troponin T and effects of cardiomyopathic mutations.Proceedings of the National Academy of Sciences of the United States of America · 2025Article
- The highly conserved C-terminal end segment of troponin T binds tropomyosin and actin to function in modulating contractile kinetics.Proceedings of the National Academy of Sciences of the United States of America · 2025Article
- The role of the troponin T interactions with actin in regulation of cardiac thin filament revealed by the troponin T pathogenic variant Ile79Asn.Journal of molecular and cellular cardiology · 2025Article
- Velcro-binding by cardiac troponin-I traps tropomyosin on actin in a low-energy relaxed state.Biochemical and biophysical research communications · 2025Article
- Troponin I - a comprehensive review of its function, structure, evolution, and role in muscle diseases.Animal cells and systems · 2025Review
- Troponin Structural Dynamics in the Native Cardiac Thin Filament Revealed by Cryo Electron Microscopy.Journal of molecular biology · 2024Article
- Exploring contractile protein mechanisms and target medications for cardiomyopathic patients with diastolic dysfunction.Pediatric discovery · 2024Review
- Free-Energy Surfaces of Two Cardiac Thin Filament Conformational Changes during Muscle Contraction.The journal of physical chemistry. B · 2022Article
- Genotype-Phenotype Associations with Restrictive Cardiomyopathy Induced by Pathogenic Genetic Mutations.Reviews in cardiovascular medicine · 2022Review
- Genetic predisposition study of heart failure and its association with cardiomyopathy.The Egyptian heart journal : (EHJ) : official bulletin of the Egyptian Society of Cardiology · 2022Review
- Significance of Cardiac Troponins as an Identification Tool in COVID-19 Patients Using Biosensors: An Update.Frontiers in molecular biosciences · 2022Review
- Inhibition of MicroRNA-206 Ameliorates Ischemia-Reperfusion Arrhythmia in a Mouse Model by Targeting Connexin43.Journal of cardiovascular translational research · 2020Article
- The actin 'A-triad's' role in contractile regulation in health and disease.The Journal of physiology · 2020Review
- Infantile restrictive cardiomyopathy: cTnI-R170G/W impair the interplay of sarcomeric proteins and the integrity of thin filaments.PloS one · 2020Article
- A case report of recessive restrictive cardiomyopathy caused by a novel mutation in cardiac troponin I (TNNI3).BMC medical genetics · 2019Article
- CaBiophysical journal · 2018Article
- Cardiac troponins may be irreversibly modified by glycation: novel potential mechanisms of cardiac performance modulation.Scientific reports · 2018Article
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Authors and funding
8 authors at 3 institutions in 1 country.
Funding
Abstract
rationaleCa(2+) control of troponin-tropomyosin position on actin regulates cardiac muscle contraction. The inhibitory subunit of troponin, cardiac troponin (cTn)I is primarily responsible for maintaining a tropomyosin conformation that prevents crossbridge cycling. Despite extensive characterization of cTnI, the precise role of its C-terminal domain (residues 193 to 210) is unclear. Mutations within this region are associated with restrictive cardiomyopathy, and C-terminal deletion of cTnI, in some species, has been associated with myocardial stunning.
objectiveWe sought to investigate the effect of a cTnI deletion-removal of 17 amino acids from the C terminus- on the structure of troponin-regulated tropomyosin bound to actin. METHODS AND
resultsA truncated form of human cTnI (cTnI(1-192)) was expressed and reconstituted with troponin C and troponin T to form a mutant troponin. Using electron microscopy and 3D image reconstruction, we show that the mutant troponin perturbs the positional equilibrium dynamics of tropomyosin in the presence of Ca(2+). Specifically, it biases tropomyosin position toward an "enhanced C-state" that exposes more of the myosin-binding site on actin than found with wild-type troponin.
conclusionsIn addition to its well-established role of promoting the so-called "blocked-state" or "B-state," cTnI participates in proper stabilization of tropomyosin in the "Ca(2+)-activated state" or "C-state." The last 17 amino acids perform this stabilizing role. The data are consistent with a "fly-casting" model in which the mobile C terminus of cTnI ensures proper conformational switching of troponin-tropomyosin. Loss of actin-sensing function within this domain, by pathological proteolysis or cardiomyopathic mutation, may be sufficient to perturb tropomyosin conformation.
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