Mutations in cardiac myosin binding protein-C (cMyBP-C) lead to sudden death in young individuals with Familial Hypertrophic Cardiomyopathy. Despite Its clinical importance and its association with the actomyosin molecular motor of the heart, a significant gap still remains in understanding how cMyBP-C modulates cardiac power production. In addition, cMyBP-C is phosphorylated following p-adrenergic stimulation, suggesting that cMyBP-C Itself may be regulated in a phosphorylation-dependent manner. This Program Project (3 projects and 3 cores) will provide a comprehensive molecular understanding of cMyBP-C function, its regulation by phosphorylation, and its impact on cardiac contractility. Using state-ofthe- art techniques, we will characterize cMyBP-C's structure and function through studies ranging from the mechanics of the whole heart down to interactions between a single cMyBP-C molecule and the actomyosin molecular motor. Project #1 will use high resolution 3-dimensional electron microscopic reconstruction to characterize the structure of cMyBP-C and its sarcomeric organization, providing insight to its functional capacity. Project #2 will use the laser trap to assess cMyBP-C's ability to modulate actomyosin power production at the single molecule level, while Project #3 will use transgenic mouse models to define the role of cMyBP-C's putative actin-binding and its phosphorylation on cardiac function under various physiological conditions. The Ventricular and Cardiac Fiber Characterization and Integration Core (Core B) will gather the ventricular performance and fiber mechanical data to bridge the physiological gap between the single molecule and whole animal studies. In addition, the Core will provide a modeling platform to integrate the data from all physiological levels into a mechanistic model of cMyBP-C functionality. The Mouse and cMyBP-C Protein Production Core (Core C) will generate mice with mutant cMyBP-C and in vitro expression of mutant cMyBP-C protein at its actin-binding and phosphorylation domains. These hearts and protein will be studied at all anatomical levels by the various projects. The Program Project's long term goals are to: 1) define cMyBP-C's molecular structure and sarcomeric organization;2) determine how cMyBP-C modulates cardiac function in a phosphorylation-dependent manner;3) define why alterations in cMyBP-C phosphorylation are associated with heart failure in humans.

Public Health Relevance

Pumping of the heart Is generated by Interactions between thin and thick, contractile protein filaments within cardiac muscle. Cardiac myosin-binding protein-C (cMyBP-C) is a thick filament component that modulates cardiac contraction. Genetic defects in cMyBP-C result in heart failure and sudden death.:: Gaps in our understanding of cMyBP-C functionality still remain. This PPG will define cMyBP-C's molecular structure function, and regulation focusing on cMyBP-C as a target for therapeutic intervention.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Program Projects (P01)
Project #
5P01HL059408-15
Application #
8611945
Study Section
Heart, Lung, and Blood Initial Review Group (HLBP)
Program Officer
Wang, Lan-Hsiang
Project Start
2000-02-01
Project End
2015-01-31
Budget Start
2014-02-01
Budget End
2015-01-31
Support Year
15
Fiscal Year
2014
Total Cost
$3,812,331
Indirect Cost
$532,452
Name
University of Vermont & St Agric College
Department
Physiology
Type
Schools of Medicine
DUNS #
066811191
City
Burlington
State
VT
Country
United States
Zip Code
05405
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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
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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
Bhuiyan, Md Shenuarin; McLendon, Patrick; James, Jeanne et al. (2016) In vivo definition of cardiac myosin-binding protein C's critical interactions with myosin. Pflugers Arch 468:1685-95
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James, Jeanne; Robbins, Jeffrey (2016) Healing a Heart Through Genetic Intervention. Circ Res 118:920-2

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