The long term goal of this project is to provide new insights into the molecular structure of the contractile filaments of muscle and the structural changes that underlie contraction and its regulation.
Specific aims are: (1) to describe the structural changes that occur in myosin crossbridges during their cycle of attachment to actin when a muscle contracts; (2) to define the regulatory structural changes that occur in the contractile filaments when they are activated; (3) to elucidate further the crossbridge arrangement and backbone structure of the myosin filaments of smooth and striated muscles. These questions will be approached using high resolution electron microscopy, combined with image analysis, to elucidate the structures of contractile molecules, filaments and whole muscles in relaxed and activated states. Intact smooth and striated muscle tissue, in the relaxed or contracting state, will be studied by rapid freezing and cryosectioning methods; isolated filaments by negative staining or """"""""frozen hydrated"""""""" methodology combined with minimal electron dose methods; and purified muscle proteins by rotary shadowing. The results of this project should broaden our understanding of the structure of healthy muscle and of the molecular processes underlying contraction and its regulation. Such knowledge is essential to an understanding of defects in structure that occur in diseased states.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR034711-08
Application #
3156919
Study Section
Molecular Cytology Study Section (CTY)
Project Start
1984-12-01
Project End
1993-11-30
Budget Start
1991-12-01
Budget End
1993-11-30
Support Year
8
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Massachusetts Medical School Worcester
Department
Type
Schools of Medicine
DUNS #
660735098
City
Worcester
State
MA
Country
United States
Zip Code
01655
Lee, Kyoung Hwan; Sulbarán, Guidenn; Yang, Shixin et al. (2018) Interacting-heads motif has been conserved as a mechanism of myosin II inhibition since before the origin of animals. Proc Natl Acad Sci U S A 115:E1991-E2000
Mun, Ji Young; Kensler, Robert W; Harris, Samantha P et al. (2016) The cMyBP-C HCM variant L348P enhances thin filament activation through an increased shift in tropomyosin position. J Mol Cell Cardiol 91:141-7
Previs, Michael J; Mun, Ji Young; Michalek, Arthur J et al. (2016) Phosphorylation and calcium antagonistically tune myosin-binding protein C's structure and function. Proc Natl Acad Sci U S A 113:3239-44
Yang, Shixin; Woodhead, John L; Zhao, Fa-Qing et al. (2016) An approach to improve the resolution of helical filaments with a large axial rise and flexible subunits. J Struct Biol 193:45-54
Previs, Michael J; Prosser, Benjamin L; Mun, Ji Young et al. (2015) Myosin-binding protein C corrects an intrinsic inhomogeneity in cardiac excitation-contraction coupling. Sci Adv 1:
Sulbarán, Guidenn; Alamo, Lorenzo; Pinto, Antonio et al. (2015) An invertebrate smooth muscle with striated muscle myosin filaments. Proc Natl Acad Sci U S A 112:E5660-8
Lee, Kyounghwan; Harris, Samantha P; Sadayappan, Sakthivel et al. (2015) Orientation of myosin binding protein C in the cardiac muscle sarcomere determined by domain-specific immuno-EM. J Mol Biol 427:274-86
Kirk, Jonathan A; Chakir, Khalid; Lee, Kyoung Hwan et al. (2015) Pacemaker-induced transient asynchrony suppresses heart failure progression. Sci Transl Med 7:319ra207
Mun, Ji Young; Previs, Michael J; Yu, Hope Y et al. (2014) Myosin-binding protein C displaces tropomyosin to activate cardiac thin filaments and governs their speed by an independent mechanism. Proc Natl Acad Sci U S A 111:2170-5
Craig, Roger; Lee, Kyoung Hwan; Mun, Ji Young et al. (2014) Structure, sarcomeric organization, and thin filament binding of cardiac myosin-binding protein-C. Pflugers Arch 466:425-31

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