ArticleBiophysical journal2012
Kinetic mechanism of Ca²⁺-controlled changes of skeletal troponin I in psoas myofibrils.
Article in Biophysical journal, 2012. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 5 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Who cites it
5 citing papers in PubMed, 5 citations in OpenAlex.
- Assessing Cardiac Contractility From Single Molecules to Whole Hearts.JACC. Basic to translational science · 2024Review
- Cycling Cross-Bridges Contribute to Thin Filament Activation in Human Slow-Twitch Fibers.Frontiers in physiology · 2020Article
- Kinetic coupling of phosphate release, force generation and rate-limiting steps in the cross-bridge cycle.Journal of muscle research and cell motility · 2017Review
- The dilated cardiomyopathy-causing mutation ACTC E361G in cardiac muscle myofibrils specifically abolishes modulation of Ca(2+) regulation by phosphorylation of troponin I.Biophysical journal · 2014Article
- Structural dynamics of troponin during activation of skeletal muscle.Proceedings of the National Academy of Sciences of the United States of America · 2014Article
Corrections and comments
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Authors and funding
10 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Conformational changes in the skeletal troponin complex (sTn) induced by rapidly increasing or decreasing the [Ca(2+)] were probed by 5-iodoacetamidofluorescein covalently bound to Cys-133 of skeletal troponin I (sTnI). Kinetics of conformational changes was determined for the isolated complex and after incorporating the complex into rabbit psoas myofibrils. Isolated and incorporated sTn exhibited biphasic Ca(2+)-activation kinetics. Whereas the fast phase (k(obs)∼1000 s(-1)) is only observed in this study, where kinetics were induced by Ca(2+), the slower phase resembles the monophasic kinetics of sTnI switching observed in another study (Brenner and Chalovich. 1999. Biophys. J. 77:2692-2708) that investigated the sTnI switching induced by releasing the feedback of force-generating cross-bridges on thin filament activation. Therefore, the slower conformational change likely reflects the sTnI switch that regulates force development. Modeling reveals that the fast conformational change can occur after the first Ca(2+) ion binds to skeletal troponin C (sTnC), whereas the slower change requires Ca(2+) binding to both regulatory sites of sTnC. Incorporating sTn into myofibrils increased the off-rate and lowered the Ca(2+) sensitivity of sTnI switching. Comparison of switch-off kinetics with myofibril force relaxation kinetics measured in a mechanical setup indicates that sTnI switching might limit the rate of fast skeletal muscle relaxation.
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