Related Experiment Video

Updated: Sep 26, 2025

Investigating the Pathogenesis of MYH7 Mutation Gly823Glu in Familial Hypertrophic Cardiomyopathy using a Mouse Model
03:45

Investigating the Pathogenesis of MYH7 Mutation Gly823Glu in Familial Hypertrophic Cardiomyopathy using a Mouse Model

Published on: August 8, 2022

3.8K

Functional Characterization of Cardiac Actin Mutants Causing Hypertrophic (p.A295S) and Dilated Cardiomyopathy

Roua Hassoun1,2, Constanze Erdmann3, Sebastian Schmitt4

  • 1Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Medical Faculty, Ruhr University Bochum, D-44791 Bochum, Germany.

International Journal of Molecular Sciences
|April 23, 2022
PubMed

Insights

Human cardiac actin mutants linked to cardiomyopathy were studied. These actin variants affect filament formation and calcium sensitivity, with potential therapeutic implications for dilated cardiomyopathy.

Area of Science:

  • Molecular Biology
  • Cardiovascular Research
  • Protein Biochemistry

Background:

  • Cardiomyopathies, including hypertrophic (HCM) and dilated (DCM) forms, are often linked to mutations in cardiac actin.
  • Understanding the molecular mechanisms of these mutations is crucial for developing targeted therapies.

Purpose of the Study:

  • To characterize the structural and functional properties of human wild-type (wt) cardiac α-actin and its disease-associated mutants (p.A295S, p.R312H, p.E361G).
  • To investigate the impact of these mutations on actin polymerization, calcium (Ca2+) sensitivity, and interactions with cardiac regulatory proteins.

Main Methods:

  • Expression of recombinant wt and mutant cardiac α-actin using the baculovirus/Sf21 insect cell system.
  • Biochemical assays including DNase I inhibition, electron microscopy, and TRITC-phalloidin staining to assess actin integrity and filament formation.
  • Functional assays measuring Ca2+-sensitivity of myosin-S1 ATPase stimulation and pyrene-labeled tropomyosin movement.

Main Results:

  • Actin variants maintained native structure and formed filaments with mutant-specific differences in length and straightness.
  • HCM (p.A295S) and DCM (p.R312H, p.E361G) mutants exhibited altered Ca2+-sensitivity of myosin-S1 ATPase stimulation.
  • Levosimendan corrected the reduced Ca2+-sensitivity in DCM mutants; cardiac myosin-binding protein-C affected Ca2+-sensitivity differently across mutants.

Conclusions:

  • Cardiac actin mutations associated with HCM and DCM significantly alter actin filament properties and Ca2+-dependent contractility.
  • The findings provide insights into the molecular basis of cardiomyopathies and highlight potential therapeutic targets, such as levosimendan for DCM.

Keywords:
calcium sensitivitycardiac actincardiomyopathieslevosimendanmyosin binding protein Cmyosin subfragment 1

More Related Videos

Probing Myosin Ensemble Mechanics in Actin Filament Bundles Using Optical Tweezers06:53

Probing Myosin Ensemble Mechanics in Actin Filament Bundles Using Optical Tweezers

Published on: May 4, 2022

2.3K
An Approach to Study Shape-Dependent Transcriptomics at a Single Cell Level06:02

An Approach to Study Shape-Dependent Transcriptomics at a Single Cell Level

Published on: November 2, 2020

5.8K

Related Concept Videos

Cardiomyopathy III: Hypertrophic Cardiomyopathy01:29

Cardiomyopathy III: Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy, or HCM, is an autosomal dominant genetic disorder characterized by asymmetric left ventricular hypertrophy without ventricular dilation. It is more common in men and is typically diagnosed in young, athletic adults.EtiologyHCM is primarily genetic and is caused by mutations in genes encoding sarcomeric proteins. Researchers have identified over 1400 mutations across at least 11 different genes. Among these, the most frequently occurring mutations are found in the...
73
Cardiomyopathy II: Dilated Cardiomyopathy01:30

Cardiomyopathy II: Dilated Cardiomyopathy

Dilated cardiomyopathy, or DCM, is a progressive myocardial disorder characterized by ventricular chamber dilation and contractile dysfunction.EtiologyVarious factors can cause DCM, including hypertension and heavy alcohol intake, which contribute to the weakening and enlargement of the heart muscle. Viral infections, such as Coxsackievirus B, adenoviruses, and influenza, can lead to DCM by causing inflammation and damage to heart tissue. Certain chemotherapeutic agents, including daunorubicin,...
43
Cardiomyopathy I: Introduction and Classification01:25

Cardiomyopathy I: Introduction and Classification

Cardiomyopathy, or CMP, is a group of diseases affecting the myocardial structure, impairing its ability to pump blood effectively. This condition can lead to arrhythmias, heart failure, or sudden cardiac death.Cardiomyopathies are classified into primary and secondary categories:Primary Cardiomyopathy refers to conditions involving only the heart muscle that are often idiopathic (of unknown cause) or genetic. They primarily affect the myocardium without the involvement of other systemic...
89
Structure of Cardiac Muscles01:13

Structure of Cardiac Muscles

Cardiac muscle, or myocardium, is a specialized type of muscle found exclusively in the heart. Its unique structural and functional characteristics enable the heart to perform its vital role of pumping blood throughout the body continuously and rhythmically. The cardiac muscle cells, or cardiomyocytes, possess an endomysium and perimysium but do not have an epimysium.
Compared to skeletal muscles, cardiac muscle cells are small and mostly have a single nucleus. Additionally, they are usually...
14.3K
Heart Failure II: Pathophysiology01:29

Heart Failure II: Pathophysiology

Systolic Heart Failure and Compensatory MechanismsSystolic heart failure (also termed HFrEF, Heart Failure with Reduced Ejection Fraction) is the most prevalent type of heart filure. It results in a decreased volume of blood being pumped from the ventricle. The aortic arch and carotid sinuses have baroreceptors that detect reduced blood pressure, triggering the sympathetic nervous system (SNS) to release epinephrine and norepinephrine. Initially, this response aims to boost heart rate and...
78
Specialized Characteristics of Cardiac Muscles01:27

Specialized Characteristics of Cardiac Muscles

The primary role of cardiac muscles is to propel blood throughout the cardiovascular system. The cardiac muscle cells, or cardiomyocytes, exhibit specialized characteristics that allow them to perform this function.
Cardiac muscle cells are smaller than skeletal muscles, averaging 10–20 mm in diameter and 50–100 mm in length. However, they have large energy demands for continuous contraction and relaxation. This energy is almost exclusively derived from aerobic metabolism of energy...
2.9K