In skeletal and cardiac muscles, contraction is triggered by an increase in the intracellular Ca concentration. During Ca transients, Ca-binding to troponin C shifts the "" equilibrium of the thin filament state toward the "" sate, promoting actomyosin interaction. Likewise, recent studies have revealed that the thin filament state is under the influence of temperature; , an increase in temperature increases active force production. In this short review, we discuss the effects of temperature on the contractile performance of mammalian striated muscle at/around body temperature, focusing especially on the temperature-dependent shift of the "" equilibrium of the thin filament state.
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http://dx.doi.org/10.3389/fphys.2020.00278 | DOI Listing |
J Gen Physiol
January 2025
Chemistry Department, University of Massachusetts Lowell, Lowell, MA, USA.
Titin is the third contractile filament in the sarcomere, and it plays a critical role in sarcomere integrity and both passive and active tension. Unlike the thick and thin filaments, which are polymers of myosin and actin, respectively, titin is a single protein that spans from Z-disk to M-line. The N2A region within titin has been identified as a signaling hub for the muscle and is shown to be involved in multiple interactions.
View Article and Find Full Text PDFFront Physiol
December 2024
National Heart and Lung Institute, Imperial College London, London, United Kingdom.
Introduction: Adrenergic activation of protein kinase A (PKA) in cardiac muscle targets the sarcolemma, sarcoplasmic reticulum, and contractile apparatus to increase contractile force and heart rate. In the thin filaments of the contractile apparatus, cardiac troponin I (cTnI) Ser22 and Ser23 in the cardiac-specific N-terminal peptide (NcTnI: residues 1 to 32) are the targets for PKA phosphorylation. Phosphorylation causes a 2-3 fold decrease of affinity of cTn for Ca associated with a higher rate of Ca dissociation from cTnC leading to a faster relaxation rate of the cardiac muscle (lusitropy).
View Article and Find Full Text PDFProtoplasma
December 2024
Institute of Cytology, Russian Academy of Sciences, Saint Petersburg, 194064, Russia.
Rhizochromulina is a genus of unicellular dictyochophycean algae (Heterokontophyta), comprising a single species R. marina and numerous strains. Recently, we described the first arctic rhizochromuline-Rhizochromulina sp.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
State key laboratory of Integration and Innovation of Classic Formula and Modern Chinese Medicine, National Chinmedomics Research Center, National TCM Key Laboratory of Serum Pharmacochemistry, Metabolomics Laboratory, Department of Pharmaceutical Analysis, Heilongjiang University of Chinese Medicine, Heping Road 24, Harbin 150040, China; State Key Laboratory of Dampness Syndrome, The Second Affiliated Hospital Guangzhou University of Chinese Medicine, Dade Road 111, Guangzhou, China. Electronic address:
ASPN-1, a novel glucan with a molecular weight of 33.31 kDa, was purified from Acanthopanax senticosus stems, characterized in structure, and evaluated for antitumor potential. The analysis of the structure of ASPN-1 revealed that it consisted of a backbone constructed from →4)-α-D-Glcp-(1 → glucosyls, branched at the O-3 position by an α-D-Glcp-(1 → residue and at the O-6 positions with α-D-Glcp-(1 → 6)-α-D-Glcp-(1 → and/or α-D-Glcp-(1 → residues.
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