ArticleBiophysical journal1999
Kinetics of thin filament activation probed by fluorescence of N-((2-(iodoacetoxy)ethyl)-N-methyl)amino-7-nitrobenz-2-oxa-1,3-diazole-labeled troponin I incorporated into skinned fibers of rabbit psoas muscle: implications for regulation of muscle contraction.
Article in Biophysical journal, 1999. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 35 papers.
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Who cites it
35 citing papers in PubMed, 57 citations in OpenAlex.
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- Negative Charges Introduced Near the IT Helix of Cardiac Troponin T Stabilize the Active State of Actin Filaments.Biochemistry · 2023Article
- Why make a strong muscle weaker?The Journal of general physiology · 2021Article
- Cycling Cross-Bridges Contribute to Thin Filament Activation in Human Slow-Twitch Fibers.Frontiers in physiology · 2020Article
- New insights provided by myofibril mechanics in inherited cardiomyopathies.Conditioning medicine · 2019Article
- Kinetic coupling of phosphate release, force generation and rate-limiting steps in the cross-bridge cycle.Journal of muscle research and cell motility · 2017Review
- Differences in Contractile Function of Myofibrils within Human Embryonic Stem Cell-Derived Cardiomyocytes vs. Adult Ventricular Myofibrils Are Related to Distinct Sarcomeric Protein Isoforms.Frontiers in physiology · 2017Article
- Pathomechanisms in heart failure: the contractile connection.Journal of muscle research and cell motility · 2015Review
- Structural dynamics of troponin during activation of skeletal muscle.Proceedings of the National Academy of Sciences of the United States of America · 2014Article
- Ablation of smooth muscle caldesmon affects the relaxation kinetics of arterial muscle.Pflugers Archiv : European journal of physiology · 2013Article
- Kinetic mechanism of Ca²⁺-controlled changes of skeletal troponin I in psoas myofibrils.Biophysical journal · 2012Article
- Calcium binding kinetics of troponin C strongly modulate cooperative activation and tension kinetics in cardiac muscle.Journal of molecular and cellular cardiology · 2011Article
- Myofilament length dependent activation.Journal of molecular and cellular cardiology · 2010Review
- Insights into the kinetics of Ca2+-regulated contraction and relaxation from myofibril studies.Pflugers Archiv : European journal of physiology · 2009Article
- Kinetic mechanism of the Ca2+-dependent switch-on and switch-off of cardiac troponin in myofibrils.Biophysical journal · 2007Article
- Sarcomere lattice geometry influences cooperative myosin binding in muscle.PLoS computational biology · 2007Article
- Tension generation and relaxation in single myofibrils from human atrial and ventricular myocardium.Pflugers Archiv : European journal of physiology · 2007Article
- Thin-filament regulation of force redevelopment kinetics in rabbit skeletal muscle fibres.The Journal of physiology · 2007Article
- Kinetics of cardiac thin-filament activation probed by fluorescence polarization of rhodamine-labeled troponin C in skinned guinea pig trabeculae.Biophysical journal · 2006Article
- Initiation of the power stroke in muscle: insights from the phosphate analog AlF4.Proceedings of the National Academy of Sciences of the United States of America · 2005Article
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Authors and funding
2 authors at 2 institutions in 2 countries.
Funding
Abstract
Making use of troponin with fluorescently labeled troponin I subunit (N-((2-(iodoacetoxy)ethyl)-N-methyl)amino-7-nitrobenz-2-oxa-1, 3-diazole-troponin I, IANBD-TnI) that had previously been described in solution studies as a probe for thin filament activation (. Proc. Natl. Acad. Sci. 77:7209-7213), we present a new approach that allows the kinetics of thin filament activation to be studied in skinned muscle fibers. After the exchange of native troponin for fluorescently labeled troponin, the fluorescence intensity is sensitive to both changes in calcium concentration and actin attachment of cross-bridges in their strong binding states (. Biophys. J. 77:000-000). Imposing rapid changes in the fraction of strongly attached cross-bridges, e.g., by switching from isometric contraction to high-speed shortening, causes changes in thin filament activation at fixed Ca(2+) concentrations that can be followed by recording fluorescence intensity. Upon changing to high-speed shortening we observed small (<20%) changes in fluorescence that became faster at higher Ca(2+) concentrations. At all Ca(2+) concentrations, these changes are more than 10-fold faster than force redevelopment subsequent to the period of unloaded shortening. We interpret this as an indication that equilibration among different states of the thin filament is rapid and becomes faster as Ca(2+) is raised. Fast equilibration suggests that the rate constant of force redevelopment is not limited by changes in the activation level of thin filaments induced by the isotonic contraction before force redevelopment. Instead, our modeling shows that, in agreement with our previous proposal for the regulation of muscle contraction, a rapid and Ca(2+)-dependent equilibration among different states of the thin filament can fully account for the Ca(2+) dependence of force redevelopment and the fluorescence changes described in this study.
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