ArticleThe Journal of physiology2002
Thin filament near-neighbour regulatory unit interactions affect rabbit skeletal muscle steady-state force-Ca(2+) relations.
Article in The Journal of physiology, 2002. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 63 papers.
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Who cites it
63 citing papers in PubMed, 91 citations in OpenAlex.
- Myosin-actin crossbridge independent sarcomere length induced CaJournal of molecular and cellular cardiology · 2025Article
- Competing effects of activation history on force and cytosolic CaPflugers Archiv : European journal of physiology · 2025Article
- Design Principles and Benefits of Spatially Explicit Models of Myofilament Function.Methods in molecular biology (Clifton, N.J.) · 2024Article
- Creatine Kinase Equilibration and ΔGInternational journal of molecular sciences · 2023Article
- High-resolution cryo-EM structure of the junction region of the native cardiac thin filament in relaxed state.PNAS nexus · 2023Article
- The force of the myosin motor sets cooperativity in thin filament activation of skeletal muscles.Communications biology · 2022Article
- The effect of variable troponin C mutation thin filament incorporation on cardiac muscle twitch contractions.Journal of molecular and cellular cardiology · 2021Article
- The structure of the native cardiac thin filament at systolic CaProceedings of the National Academy of Sciences of the United States of America · 2021Article
- Force variability is mostly not motor noise: Theoretical implications for motor control.PLoS computational biology · 2021Article
- Mechanical contribution to muscle thin filament activation.The Journal of biological chemistry · 2020Article
- A new twist on tropomyosin binding to actin filaments: perspectives on thin filament function, assembly and biomechanics.Journal of muscle research and cell motility · 2020Review
- Functional outcomes of structural peculiarities of striated muscle tropomyosin.Journal of muscle research and cell motility · 2020Review
- A Stochastic Multiscale Model of Cardiac Thin Filament Activation Using Brownian-Langevin Dynamics.Biophysical journal · 2019Article
- Tropomyosin dynamics during cardiac muscle contraction as governed by a multi-well energy landscape.Progress in biophysics and molecular biology · 2019Article
- IGF1 and NRG1 Enhance Proliferation, Metabolic Maturity, and the Force-Frequency Response in hESC-Derived Engineered Cardiac Tissues.Stem cells international · 2017Article
- Effects of cross-bridge compliance on the force-velocity relationship and muscle power output.PloS one · 2017Article
- Maximum limit to the number of myosin II motors participating in processive sliding of actin.Scientific reports · 2016Article
- Structural determinants of muscle thin filament cooperativity.Archives of biochemistry and biophysics · 2016Review
- Fluorescent Protein-Based Ca2+ Sensor Reveals Global, Divalent Cation-Dependent Conformational Changes in Cardiac Troponin C.PloS one · 2016Article
- Cardiac Troponin and Tropomyosin: Structural and Cellular Perspectives to Unveil the Hypertrophic Cardiomyopathy Phenotype.Frontiers in physiology · 2016Review
3 more citing papers are in PubMed but not listed here.
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Authors and funding
6 authors at 1 institution in 1 country.
Funding
Abstract
The role of cooperative interactions between individual structural regulatory units (SUs) of thin filaments (7 actin monomers : 1 tropomyosin : 1 troponin complex) on steady-state Ca(2+)-activated force was studied. Native troponin C (TnC) was extracted from single, de-membranated rabbit psoas fibres and replaced by mixtures of purified rabbit skeletal TnC (sTnC) and recombinant rabbit sTnC (D27A, D63A), which contains mutations that disrupt Ca(2+) coordination at N-terminal sites I and II (xxsTnC). Control experiments in fibres indicated that, in the absence of Ca(2+), both sTnC and xxsTnC bind with similar apparent affinity to sTnC-extracted thin filaments. Endogenous sTnC-extracted fibres reconstituted with 100 % xxsTnC did not develop Ca(2+)-activated force. In fibres reconstituted with mixtures of sTnC and xxsTnC, maximal Ca(2+)-activated force increased in a greater than linear manner with the fraction of sTnC. This suggests that Ca(2+) binding to functional Tn can spread activation beyond the seven actins of an SU into neighbouring units, and the data suggest that this functional unit (FU) size is up to 10-12 actins. As the number of FUs was decreased, Ca(2+) sensitivity of force (pCa(50)) decreased proportionally. The slope of the force-pCa relation (the Hill coefficient, n(H)) also decreased when the reconstitution mixture contained < 50 % sTnC. With 15 % sTnC in the reconstitution mixture, n(H) was reduced to 1.7 +/- 0.2, compared with 3.8 +/- 0.1 in fibres reconstituted with 100 % sTnC, indicating that most of the cooperative thin filament activation was eliminated. The results suggest that cooperative activation of skeletal muscle fibres occurs primarily through spread of activation to near-neighbour FUs along the thin filament (via head-to-tail tropomyosin interactions).
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