The molecular mechanism by which cMyBP-C exerts its effect on actomyosin force power generating system remains largely undefined. With its low ratio relative to myosin and it being located in distinct regions of the thick filament, we will determine in this Project how cMyBP-C's modulates actomyosin's power generation by either interacting with a limited population of crossbridges or whether it cooperatively affects all crossbridges within the thick filament. This project serves as a physiological bridge between the animal (Project #3, Robbins), whole heart (Core B, Kass) and fiber (Core B, Palmer, Maughan) studies.
In Aim #1, we will use state-of-the-art single molecule biophysical techniques (e.g. laser trap assay) to probe the effect that cMyBP-C exerts on actomyosin function along the length a single native thick filament isolated from transgenic mice designed in Project #3 (Robbins) and produced in Core C (Robbins).
In Aim #2, we will use expressed N-terminal fragments of cMyBP-C produced in Core C (Robbins) to probe the binding affinity of these fragments for actin and/or myosin. Thus, these data and that obtained in Project #1 (Craig), Project #3 (Robbins) and Core B (Palmer) will help define cMyBP-C's specific binding partners (i.e. myosin and/or actin) and thus its physiological site of action. In combination with motility and laser trap assays, we will determine if the N-terminus of CMyBP-C limits myosin's attachment rate to actin or if it directly affects myosin's inherent molecular mechanics and kinetics. Finally, in Aim #3 we will characterize how phosphorylation regulates cMyBP-C action. Using transgenic mouse models (Core C, Robbins) expressing cMyBP C mutants having alanine or aspartic acid substitutions for one or more of the three phosphorylatable serines, we will determine the functional importance of phosphorylation and the hierarchical importance of each site using native thick filaments containing mutant cMyBP-C as well as N-terminal fragments having the same mutations. Once the molecular mechanism of cMyBP-C is defined, the potential for novel therapeutics or clinical intervention may be possible in cases of heart failure associated with genetic mutations in cMyBP-C.
cMyBP-C is critical to normal cardiac performance. Using single molecule biophysical techniques to characterize the molecular mechanism of cMyBP-C function, the results may provide the potential for novel therapies in cases of heart failure associated with genetic mutations in cMyBP-C.
|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|
|Warshaw, David M (2016) HEART DISEASE. Throttling back the heart's molecular motor. Science 351:556-7|
|James, Jeanne; Robbins, Jeffrey (2016) Healing a Heart Through Genetic Intervention. Circ Res 118:920-2|
|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|
|Gupta, Manish K; McLendon, Patrick M; Gulick, James et al. (2016) UBC9-Mediated Sumoylation Favorably Impacts Cardiac Function in Compromised Hearts. Circ Res 118:1894-905|
|Michalek, Arthur J; Kennedy, Guy G; Warshaw, David M et al. (2015) Flexural Stiffness of Myosin Va Subdomains as Measured from Tethered Particle Motion. J Biophys 2015:465693|
|LeWinter, Martin M; Palmer, Bradley M (2015) Updating the physiology and pathophysiology of cardiac Myosin-binding protein-C. Circ Heart Fail 8:417-21|
|McLendon, Patrick M; Robbins, Jeffrey (2015) Proteotoxicity and cardiac dysfunction. Circ Res 116:1863-82|
|Kirk, Jonathan A; Chakir, Khalid; Lee, Kyoung Hwan et al. (2015) Pacemaker-induced transient asynchrony suppresses heart failure progression. Sci Transl Med 7:319ra207|
Showing the most recent 10 out of 162 publications