Myosin has an intrinsic ability to organize into ordered thick filaments that mediate muscle contraction. Here, we use surface plasmon resonance and light scattering analysis to further characterize the molecular determinants that guide myosin filament assembly. Both assays identify a cluster of lysine and arginine residues as important for myosin polymerization in vitro. Moreover, in cardiomyocytes, replacement of these charged residues by alanine severely affects the incorporation of myosin into the distal ends of the sarcomere. Our findings show that a novel assembly element with a distinct charge profile is present at the C-terminus of sarcomeric myosins.
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http://dx.doi.org/10.1016/j.febslet.2012.06.019 | DOI Listing |
PLoS Biol
January 2025
Department of Biomedical and Translational Sciences, Macon & Joan Brock Virginia Health Sciences at Old Dominion University, Norfolk, Virginia, United States of America.
Every heartbeat depends on cyclical contraction-relaxation produced by the interactions between myosin-containing thick and actin-based thin filaments (TFs) arranged into a crystalline-like lattice in the cardiac sarcomere. Therefore, the maintenance of thin filament length is crucial for myocardium function. The thin filament is comprised of an actin backbone, the regulatory troponin complex and tropomyosin that controls interactions between thick and thin filaments.
View Article and Find Full Text PDFCell Mol Biol Lett
January 2025
School of Medicine, Shanghai University, Shanghai, 200444, China.
Background: Interfacial heterogeneity is widely explored to reveal molecular mechanisms of force-mediated pathways due to biased tension. However, the influence of cell density,, curvature, and interfacial heterogeneity on underlying pathways of mechanotransduction is obscure.
Methods: Polydimethylsiloxane (PDMS)-based stencils were micropatterned to prepare the micropores for cell culture.
Nat Commun
January 2025
Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL, USA.
Assembly of actin-based stereocilia is critical for cochlear hair cells to detect sound. To tune their mechanosensivity, stereocilia form bundles composed of graded rows of ascending height, necessitating the precise control of actin polymerization. Myosin 15 (MYO15A) drives hair bundle development by delivering critical proteins to growing stereocilia that regulate actin polymerization via an unknown mechanism.
View Article and Find Full Text PDFJ Physiol Sci
January 2025
Department of Frontier Health Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10 Higashiogu, Arakawa-Ku, 116-8551, Tokyo, Japan. Electronic address:
Actin linked regulatory mechanisms are known to contribute contraction/relaxation in smooth muscle. In order to clarify whether modulation of polymerization/depolymerization of actin filaments affects relaxation process, we examined the effects of cytochalasin D on relaxation process by Ca removal after Ca-induced contraction of β-escin skinned (cell membrane permeabilized) taenia cecum and carotid artery preparations from guinea pigs. Cytochalasin D, an inhibitor of actin polymerization, significantly suppressed the force during relaxation both in skinned taenia cecum and carotid artery.
View Article and Find Full Text PDFJ Cell Sci
January 2025
Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093, USA.
The plasma membrane and the underlying skeleton form a protective barrier for eukaryotic cells. The molecular players forming this complex composite material constantly rearrange under mechanical stress. One of those molecules, spectrin, is ubiquitous in the membrane skeleton and linked by short actin filaments.
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