scholarly journals Site-directed spectroscopy of cardiac myosin-binding protein C reveals effects of phosphorylation on protein structural dynamics

2016 ◽  
Vol 113 (12) ◽  
pp. 3233-3238 ◽  
Author(s):  
Brett A. Colson ◽  
Andrew R. Thompson ◽  
L. Michel Espinoza-Fonseca ◽  
David D. Thomas
Keyword(s):  
Protein C ◽  
Binding Protein ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Md Simulations ◽  
Cardiac Myosin ◽  
Myosin Binding Protein ◽  
Myosin Binding Protein C ◽  
Myosin Binding

We have used the site-directed spectroscopies of time-resolved fluorescence resonance energy transfer (TR-FRET) and double electron–electron resonance (DEER), combined with complementary molecular dynamics (MD) simulations, to resolve the structure and dynamics of cardiac myosin-binding protein C (cMyBP-C), focusing on the N-terminal region. The results have implications for the role of this protein in myocardial contraction, with particular relevance to β-adrenergic signaling, heart failure, and hypertrophic cardiomyopathy. N-terminal cMyBP-C domains C0–C2 (C0C2) contain binding regions for potential interactions with both thick and thin filaments. Phosphorylation by PKA in the MyBP-C motif regulates these binding interactions. Our spectroscopic assays detect distances between pairs of site-directed probes on cMyBP-C. We engineered intramolecular pairs of labeling sites within cMyBP-C to measure, with high resolution, the distance and disorder in the protein’s flexible regions using TR-FRET and DEER. Phosphorylation reduced the level of molecular disorder and the distribution of C0C2 intramolecular distances became more compact, with probes flanking either the motif between C1 and C2 or the Pro/Ala-rich linker (PAL) between C0 and C1. Further insight was obtained from microsecond MD simulations, which revealed a large structural change in the disordered motif region in which phosphorylation unmasks the surface of a series of residues on a stable α-helix within the motif with high potential as a protein–protein interaction site. These experimental and computational findings elucidate structural transitions in the flexible and dynamic portions of cMyBP-C, providing previously unidentified molecular insight into the modulatory role of this protein in cardiac muscle contractility.

scholarly journals On the Functional Assessment of Hypertrophic Cardiomyopathy-Causing Mutations in Human β-Cardiac Myosin and the Role of Myosin Binding Protein-C

2019 ◽  
Vol 116 (3) ◽  
pp. 466a-467a
Author(s):  
Darshan V. Trivedi ◽  
Saswata S. Sarkar ◽  
Arjun S. Adhikari ◽  
Makenna M. Morck ◽  
Kristina B. Kooiker ◽  
...  
Keyword(s):  
Hypertrophic Cardiomyopathy ◽  
Functional Assessment ◽  
Protein C ◽  
Binding Protein ◽  
Cardiac Myosin ◽  
Myosin Binding Protein ◽  
Myosin Binding Protein C ◽  
Myosin Binding

scholarly journals Role of Cardiac Myosin Binding Protein C in Sustaining Left Ventricular Systolic Stiffening

2004 ◽  
Vol 94 (9) ◽  
pp. 1249-1255 ◽  
Author(s):  
Bradley M. Palmer ◽  
Dimitrios Georgakopoulos ◽  
Paul M. Janssen ◽  
Yuan Wang ◽  
Norman R. Alpert ◽  
...  
Keyword(s):  
Protein C ◽  
Binding Protein ◽  
Left Ventricular ◽  
Cardiac Myosin ◽  
Myosin Binding Protein ◽  
Myosin Binding Protein C ◽  
Myosin Binding

The dynamic role of cardiac myosin binding protein-C during ischemia

2012 ◽  
Vol 52 (5) ◽  
pp. 1145-1154 ◽  
Author(s):  
Robert S. Decker ◽  
Sakie Nakamura ◽  
Marlene L. Decker ◽  
Mareike Sausamuta ◽  
Sammy Sinno ◽  
...  
Keyword(s):  
Protein C ◽  
Binding Protein ◽  
Cardiac Myosin ◽  
Myosin Binding Protein ◽  
Myosin Binding Protein C ◽  
Myosin Binding

Biological variation of cardiac myosin-binding protein C in healthy individuals

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Bashir Alaour ◽  
Torbjørn Omland ◽  
Janniche Torsvik ◽  
Thomas E. Kaier ◽  
Marit S. Sylte ◽  
...  
Keyword(s):  
Risk Stratification ◽  
Protein C ◽  
Myocardial Injury ◽  
Binding Protein ◽  
Biological Variation ◽  
Cardiac Myosin ◽  
Analytical Quality ◽  
Myosin Binding Protein ◽  
Myosin Binding Protein C ◽  
Myosin Binding

Abstract Objectives Cardiac myosin-binding protein C (cMyC) is a novel biomarker of myocardial injury, with a promising role in the triage and risk stratification of patients presenting with acute cardiac disease. In this study, we assess the weekly biological variation of cMyC, to examine its potential in monitoring chronic myocardial injury, and to suggest analytical quality specification for routine use of the test in clinical practice. Methods Thirty healthy volunteers were included. Non-fasting samples were obtained once a week for ten consecutive weeks. Samples were tested in duplicate on the Erenna® platform by EMD Millipore Corporation. Outlying measurements and subjects were identified and excluded systematically, and homogeneity of analytical and within-subject variances was achieved before calculating the biological variability (CVI and CVG), reference change values (RCV) and index of individuality (II). Results Mean age was 38 (range, 21–64) years, and 16 participants were women (53%). The biological variation, RCV and II with 95% confidence interval (CI) were: CVA (%) 19.5 (17.8–21.6), CVI (%) 17.8 (14.8–21.0), CVG (%) 66.9 (50.4–109.9), RCV (%) 106.7 (96.6–120.1)/−51.6 (−54.6 to −49.1) and II 0.42 (0.29–0.56). There was a trend for women to have lower CVG. The calculated RCVs were comparable between genders. Conclusions cMyC exhibits acceptable RCV and low II suggesting that it could be suitable for disease monitoring, risk stratification and prognostication if measured serially. Analytical quality specifications based on biological variation are similar to those for cardiac troponin and should be achievable at clinically relevant concentrations.

scholarly journals Cardiac Myosin-Binding Protein C Modulates the Tuning of the Molecular Motor in the Heart

2008 ◽  
Vol 95 (2) ◽  
pp. 720-728 ◽  
Author(s):  
Yves Lecarpentier ◽  
Nicolas Vignier ◽  
Patricia Oliviero ◽  
Aziz Guellich ◽  
Lucie Carrier ◽  
...  
Keyword(s):  
Protein C ◽  
Molecular Motor ◽  
Binding Protein ◽  
Cardiac Myosin ◽  
Myosin Binding Protein ◽  
Myosin Binding Protein C ◽  
Myosin Binding

scholarly journals Phosphorylation of cardiac myosin binding protein C releases myosin heads from the surface of cardiac thick filaments

2017 ◽  
Vol 114 (8) ◽  
pp. E1355-E1364 ◽  
Author(s):  
Robert W. Kensler ◽  
Roger Craig ◽  
Richard L. Moss
Keyword(s):  
Protein C ◽  
Structural Changes ◽  
Binding Protein ◽  
Cardiac Contraction ◽  
Cardiac Myosin ◽  
Cross Bridge ◽  
Myosin Binding Protein ◽  
Myosin Binding Protein C ◽  
Thick Filaments ◽  
Myosin Binding

Cardiac myosin binding protein C (cMyBP-C) has a key regulatory role in cardiac contraction, but the mechanism by which changes in phosphorylation of cMyBP-C accelerate cross-bridge kinetics remains unknown. In this study, we isolated thick filaments from the hearts of mice in which the three serine residues (Ser273, Ser282, and Ser302) that are phosphorylated by protein kinase A in the m-domain of cMyBP-C were replaced by either alanine or aspartic acid, mimicking the fully nonphosphorylated and the fully phosphorylated state of cMyBP-C, respectively. We found that thick filaments from the cMyBP-C phospho-deficient hearts had highly ordered cross-bridge arrays, whereas the filaments from the cMyBP-C phospho-mimetic hearts showed a strong tendency toward disorder. Our results support the hypothesis that dephosphorylation of cMyBP-C promotes or stabilizes the relaxed/superrelaxed quasi-helical ordering of the myosin heads on the filament surface, whereas phosphorylation weakens this stabilization and binding of the heads to the backbone. Such structural changes would modulate the probability of myosin binding to actin and could help explain the acceleration of cross-bridge interactions with actin when cMyBP-C is phosphorylated because of, for example, activation of β1-adrenergic receptors in myocardium.

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