What question did this study set out to answer?

Determine whether the N-terminal domains of cardiac myosin-binding protein C interact directly with F-actin and evaluate if this interaction is regulated by phosphorylation.

March 7, 2009Journal of Biological ChemistryOpen Access

The Myosin-binding Protein C Motif Binds to F-actin in a Phosphorylation-sensitive Manner

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Population

Murine cardiac myosin-binding protein C (cMyBP-C) 4 N-terminal domains (C0-C1-m-C2) and F-actin

Comparison

Phosphorylation of the MyBP-C regulatory motif vs Unphosphorylated state

Design

Preclinical

Authors

JSJustin F. ShafferColorado School of Mines RKRobert W. KenslerUniversity of Puerto Rico System SHSamantha P. HarrisNewYork–Presbyterian Hospital

Discussion

Member takes

Implication

May promote cross-bridge cycling via reduced actin interactions; leaves open relevance to human myocardium.

Key Points

Determine whether the N-terminal domains of cardiac myosin-binding protein C interact directly with F-actin and evaluate if this interaction is regulated by phosphorylation.
Measured binding between murine cMyBP-C N-terminal domains (C0-C1-m-C2) and F-actin using cosedimentation binding assays.
Visualized and quantified actin filament cross-linking using electron microscopy and light scattering before and after phosphorylation of the regulatory m-domain.
Unphosphorylated cMyBP-C N-terminal domains bound F-actin at a 1:1 molar ratio (Bmax ≈ 1.0) with a dissociation constant (Kd) of approximately 10 µM.
Electron microscopy and light scattering showed that unphosphorylated N-terminal domains cross-linked F-actin filaments, indicating multiple distinct actin-binding sites.
Phosphorylation of the regulatory motif reduced actin binding capacity (lowered Bmax) and completely eliminated filament cross-linking.

Structured PICO

Population

Murine cardiac myosin-binding protein C (cMyBP-C) 4 N-terminal domains (C0-C1-m-C2) and F-actin

Intervention

Phosphorylation of the MyBP-C regulatory motif (m-domain)

Comparator

Unphosphorylated state

Outcome

Binding affinity (Kd), molar binding ratio (Bmax), and actin cross-linkingsurrogate

Phosphorylation of the cMyBP-C regulatory motif reduces its binding to F-actin and eliminates actin cross-linking, which may contribute to increased cross-bridge cycling in the heart.

Cite This Study

Shaffer et al. (2009) studied this question.

synapsesocial.com/papers/6a701e3be5469ee92be0e150 https://doi.org/10.1074/jbc.m808850200

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The Myosin-binding Protein C Motif Binds to F-actin in a Phosphorylation-sensitive Manner

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

The Myosin-binding Protein C Motif Binds to F-actin in a Phosphorylation-sensitive Manner

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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