Lattice arrangement of myosin filaments correlates with fiber type in rat skeletal muscle
Year: 2019
Type: article
Abstract: The thick (myosin-containing) filaments of vertebrate skeletal muscle are arranged in a hexagonal lattice, interleaved with an array of thin (actin-containing) filaments with which they interact to produce contraction. X-ray diffraction and electron microscopy have shown that there are two types of thick filament lattice. In the simple lattice, all filaments have the same orientation about their long axis, while in the super lattice, nearest neighbors have rotations differing by 60°. Tetrapods (amphibians, reptiles, birds, mammals) typically have only a super lattice, while the simple lattice is confined to fish. We have carried out X-ray diffraction and electron microscopy of the soleus (SOL) and extensor digitorum longus (EDL) muscles of the rat and found that while the EDL has a super-lattice, as expected, the SOL has a simple lattice. The EDL and SOL of the rat are unusual in being essentially pure fast and slow muscles respectively. The mixed fiber content of most tetrapod muscles and/or lattice disorder may explain why the simple lattice has not been apparent in these vertebrates before. This is supported by only weak simple lattice diffraction in the X-ray pattern of mouse SOL, which has a greater mix of fiber types than rat. We conclude that the simple lattice might be common in tetrapods. The correlation between fiber type and filament lattice arrangement suggests that the lattice arrangement may contribute to the functional properties of a muscle. Summary The three-dimensional arrangement of thick filaments in skeletal muscle is studied by X-ray diffraction and electron microscopy. A correlation is found between thick filament lattice type (simple or super lattice) and fiber type (fast/slow). This suggests that lattice organization contributes to muscle functional properties
Language: English
Subfield: Cardiology and Cardiovascular Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Funders: U.S. Department of Energy, National Institutes of Health, Office of Science, University of Massachusetts Medical School, National Heart, Lung, and Blood Institute, National Institute of General Medical Sciences, National Institute of Arthritis and Musculoskeletal and Skin Diseases, Argonne National Laboratory
Awards: G1017699072, G102163711, G107546177, G1313983767, G1505794299, G1555076680, G1664757510, G2008846556, G2101401529, The Biophysics Collaborative Access Team, G2287611682, G262962599, G2853440140, G2887060908, G3075337988, Murine 3D Engineered Tissue Model of Human MYBPC3 Mutations, G340565428, G3592402179, Structure of The Interacting-Heads Motif in Myosin Filaments and Molecules, G409777406, G4622468616, G498139845, G5106849484, G5499275266, G5607048534, Advanced Pixel Array Detector for Time-Resolved SAXS and Fiber Diffraction, G6848031779, G6918803902, G7224072233, G7368700025, Ultramicrotome, G7532037738, G9000107310, G9000140449, G9000192123, G9000275877, G9000284726, G969889393, G993149817
OpenAlex ID: W2984508424