The arrangement of myosin and accessory proteins such as C-Protein in the vertebrate striated muscle thick filament is incompletely known. Recent experiments on the structure of frog thick filaments, however, have demonstrated that the structure of vertebrate thick filaments may be amenable to analysis by a combination of electron microscopy, optical diffraction analysis, and computer image reconstruction techniques.
The specific aim of the proposed research is to expand these studies of the frog thick filaments and to extend the studies to the determination and comparison of the structure of thick filaments isolated from fish, avian, and mammalian striated muscle. The major objective of these studies will be the determination of the arrangement and number of myosins per crossbridge level in these filaments and how C-protein is arranged relative to the underlying myosin. The studies to accomplish these aims will include: 1) the development of procedures fro the isolation of native thick filaments with minimal structural alteration from each of the species; 2) the use of combination of electron microscopy and optical diffraction analysis of the micrographs to assess the filament preservation; and 3) the use of computer image analysis of the filament images in the best electron micrographs to determine the rotational symmetry and arrangement of the myosin heads, and the arrangement of C-protein. These studies will provide basic scientific information about the structure of muscle, and will thus provide a better foundation for understanding how pathologic condition may affect the functioning of this tissue.

National Institute of Health (NIH)
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Research Project (R01)
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Biophysics and Biophysical Chemistry B Study Section (BBCB)
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Allegheny University of Health Sciences
Schools of Medicine
United States
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Kensler, R W; Woodhead, J L (1995) The chicken muscle thick filament: temperature and the relaxed cross-bridge arrangement. J Muscle Res Cell Motil 16:79-90
Kensler, R W; Peterson, S; Norberg, M (1994) The effects of changes in temperature or ionic strength on isolated rabbit and fish skeletal muscle thick filaments. J Muscle Res Cell Motil 15:69-79
Kensler, R W; Stewart, M (1993) The relaxed crossbridge pattern in isolated rabbit psoas muscle thick filaments. J Cell Sci 105 ( Pt 3):841-8
Kensler, R W; Stewart, M (1989) An ultrastructural study of crossbridge arrangement in the fish skeletal muscle thick filament. J Cell Sci 94 ( Pt 3):391-401
Levine, R J; Chantler, P D; Kensler, R W (1988) Arrangement of myosin heads on Limulus thick filaments. J Cell Biol 107:1739-47