Regulation of muscle contraction has been viewed as principally involving Ca binding to regulatory proteins on the thin filament, but while this is an important element of regulation, the mechanism does not explain the precise matching of muscle performance to the load it must lift or move. Now, it is increasingly evident that mechanisms instrinsic to the thick filament activate myosin cross-bridges as the force or load on a muscle increases. Both thick and thin filament regulatory mechanisms are featured in this special issue of the .
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http://dx.doi.org/10.1085/jgp.201812288 | DOI Listing |
Biophys Rev
December 2024
Randall Centre for Cell & Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London, London, UK.
Calcium binding to troponin triggers the contraction of skeletal and heart muscle through structural changes in the thin filaments that allow myosin motors from the thick filaments to bind to actin and drive filament sliding. Here, we review studies in which those changes were determined in demembranated fibres of skeletal and heart muscle using fluorescence for in situ structure (FISS), which determines domain orientations using polarised fluorescence from bifunctional rhodamine attached to cysteine pairs in the target domain. We describe the changes in the orientations of the N-terminal lobe of troponin C (TnC) and the troponin IT arm in skeletal and cardiac muscle cells associated with contraction and compare the orientations with those determined in isolated cardiac thin filaments by cryo-electron microscopy.
View Article and Find Full Text PDFNPJ Biofilms Microbiomes
January 2025
FLOW, Department of Engineering Mechanics, KTH, Stockholm, Sweden.
Biofilms constitute one of the most common forms of living matter, playing an increasingly important role in technology, health, and ecology. While it is well established that biofilm growth and morphology are highly dependent on the external flow environment, the precise role of fluid friction has remained elusive. We grew Bacillus subtilis biofilms on flat surfaces of a channel in a laminar flow at wall shear stresses spanning one order of magnitude (τ = 0.
View Article and Find Full Text PDFMater Today Bio
February 2025
Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer Sheva, 8410501, Israel.
Protein-based biomaterials are in high demand due to their high biocompatibility, non-toxicity, and biodegradability. In this study, we explore the bacterial secreted protein A (EspA), which self-assembles into long extracellular filaments, as a potential building block for new protein-based biomaterials. We investigated the morphological and mechanical properties of EspA filaments and how protein engineering can modify them.
View Article and Find Full Text PDFMicromachines (Basel)
December 2024
School of Integrated Circuit, Southeast University, Nanjing 210096, China.
Aluminum nitride (AlN) with a wide band gap (approximately 6.2 eV) has attractive characteristics, including high thermal conductivity, a high dielectric constant, and good insulating properties, which are suitable for the field of resistive random access memory. AlN thin films were deposited on ITO substrate using the radio-frequency magnetron sputtering technique.
View Article and Find Full Text PDFBiomolecules
December 2024
Zoological Institute RAS, St. Petersburg 199034, Russia.
Amoebozoa is a group of single-celled organisms that change their shape during locomotion. However, there is a taxon-specific complex of morphological characters inherent in the moving amoebae, known as locomotive forms. Actin is one of the proteins most important for amoeboid movement that, together with actin-binding proteins, construct the architecture of the cytoskeleton in the amoeboid cells.
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