Native myosin filaments from scallop striated muscle that have been rapidly frozen in relaxing solutions appear to be well preserved in vitreous ice. Electron micrographs of samples at -177 degrees C were recorded with an electron dose of 10 e/A2 at 1.5 microns defocus. After filament images were straightened by spline-fitting, several transforms showed well-defined layer-lines arising from the helical structure of the filament. A set of 17 near-meridional layer-lines has been collected and corrected for background and for phase and amplitude contrast functions. Preliminary helical reconstructions from this still incomplete data set reveal aspects of structure that were not apparent from earlier analysis of negatively stained filaments from scallop muscle. Individual pear-shaped myosin heads now appear to be well resolved from each other and from the filament backbone. The two heads of each myosin molecule appear to be splayed apart axially. The reconstructions also reveal that the filament backbone has a polygonal shape in cross-section, and that it appears to contain seven peripherally located subfilaments.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/0022-2836(92)90982-p | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Interaction of cardiac leiomodin with the native cardiac thin filament.
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 PDFHeterogeneous focal adhesion cytoskeleton nanoarchitectures from microengineered interfacial curvature to oversee nuclear remodeling and mechanotransduction of mesenchymal stem cells.
Cell 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.
Myosin-based nucleation of actin filaments contributes to stereocilia development critical for hearing.
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 PDFEffects of cytochalasin D on relaxation process of skinned taenia cecum and carotid artery from guinea pig.
J 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 PDFDynamic mechanisms for membrane skeleton transitions.
J 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.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!