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Updated: Jan 18, 2026

Magnetic Adjustment of Afterload in Engineered Heart Tissues
Published on: May 5, 2020
Cardiac myosin-binding protein-C acts as a tunable load sensor to regulate afterload dependence of ventricular
Laurin M Hanft1, Theodore J Kalogeris1, Daniel John Davis2
1Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, Missouri, United States.
Cardiac myosin-binding protein-C (cMyBP-C) functions as a tunable molecular sensor, adjusting cardiac muscle power output based on mechanical load. Its phosphorylation state fine-tunes this load-sensing ability to match heart performance with hemodynamic conditions.
Area of Science:
- Cardiovascular physiology
- Muscle biology
- Molecular cardiology
Background:
- Cardiac myosin-binding protein-C (cMyBP-C) is a key sarcomeric protein regulating cardiac myocyte contraction.
- Previous studies suggest cMyBP-C acts as a molecular load sensor, influencing myocyte power and shortening velocity.
- Evidence indicates myosin cross-bridges in the cMyBP-C zone are highly active during loaded contractions.
Purpose of the Study:
- To test the hypothesis that cMyBP-C is a tunable load sensor matching afterload with left ventricular (LV) performance.
- To investigate the role of cMyBP-C phosphorylation in modulating LV power response to afterload.
Main Methods:
- Comparison of afterload dependence of LV power in isolated hearts from cMyBP-C knockout (KO) mice.
- Assessment of hearts from transgenic mice expressing wild-type (WT), pseudo-phosphorylated (t3SD), or nonphosphorylatable (t3SA) cMyBP-C.
- Measurement of LV power across a range of afterloads (40-60 mmHg).
Main Results:
- cMyBP-C KO hearts showed minimal LV power changes with varying afterload.
- cMyBP-C WT hearts exhibited a steep afterload dependence of LV power.
- Pseudo-phosphorylated cMyBP-C (t3SD) hearts displayed steep afterload dependence, while nonphosphorylatable cMyBP-C (t3SA) hearts showed less dependence.
Conclusions:
- cMyBP-C functions as a tunable load sensor in the heart.
- The phosphorylation state of cMyBP-C modulates its load-sensing capacity.
- cMyBP-C plays a critical role in matching myofilament power generation with hemodynamic demands.
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