Related Experiment Video

Updated: Aug 5, 2026

A Doxorubicin-Induced Murine Model of Dilated Cardiomyopathy In Vivo
05:14

A Doxorubicin-Induced Murine Model of Dilated Cardiomyopathy In Vivo

Published on: May 16, 2020

The idiopathic dilated cardiomyopathy in man. A biochemical and molecular study on myosin

L Dalla Libera1, P Pauletto, D Piccolo

  • 1C.N.R. Centro di Studio per la Biologia e Fisiopatologia Muscolare, Università di Padova, Italia.

Basic Research in Cardiology
|January 1, 1991
PubMed

Insights

This study investigated myosin in hearts with dilated cardiomyopathy, finding atrial-like light chain 1 (ALC1) was absent in ventricles. However, ventricular-like light chain 2 (VLC2) was present in atria, correlating with depressed ATPase activity.

Area of Science:

  • Cardiology
  • Molecular Biology
  • Biochemistry

Background:

  • Idiopathic dilated cardiomyopathy (IDC) affects heart muscle function.
  • Myosin's role in cardiac contraction is critical, with varying subunit compositions potentially influencing contractile properties.

Purpose of the Study:

  • To investigate the myosin subunit composition and Ca(++)-activated ATPase activity in atrial and ventricular tissues from hearts with IDC.
  • To determine if the absence of myosin atrial-like light chain 1 (ALC1) in ventricular tissue and the presence of ventricular-like light chain 2 (VLC2) in atrial tissue are associated with altered cardiac function in IDC.

Main Methods:

  • Myosin isolation from explanted human hearts (atria and ventricles) of patients with IDC.
  • Analysis of myosin subunit composition using two-dimensional electrophoresis and immunoblotting.
  • Measurement of Ca(++)-activated ATPase activity of isolated myosin.

Main Results:

  • Myosin atrial-like light chain 1 (ALC1) was not detected in ventricular subendocardial, septal, or subepicardial layers of IDC hearts.
  • Ventricular-like light chain 2 (VLC2) was identified in both atrial and ventricular myosin from IDC hearts.
  • A depressed Ca(++)-activated ATPase activity was observed in both atrial and ventricular myosin from IDC patients compared to controls.

Conclusions:

  • The absence of ALC1 in ventricular myosin and the presence of VLC2 in atrial myosin in IDC hearts may contribute to altered cardiac mechanics.
  • Depressed Ca(++)-activated ATPase activity in atrial myosin from IDC hearts is linked to the expression of ventricular-type myosin heavy chains and VLC2.
  • The cause of depressed ATPase activity in ventricular myosin in IDC remains unclear, as myosin heavy and light chains showed no significant differences compared to controls.

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

Investigating the Pathogenesis of MYH7 Mutation Gly823Glu in Familial Hypertrophic Cardiomyopathy using a Mouse Model03:45

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

Published on: August 8, 2022

Related Concept Videos

Overview of Myosin Structure and Function01:15

Overview of Myosin Structure and Function

Myosins are a family of molecular motor proteins, first identified in the skeletal muscles, where they are responsible for muscle contraction. Along with their role in muscle contraction, these proteins also play a role in the intracellular transport of molecules and vesicles. There are twenty-four classes of myosins based on their domain sequence and organization. Of the twenty-four, six classes (Myosin I, Myosin II, Myosin V, Myosin VI, Myosin VII, and Myosin X)  have been well characterized.
Myocarditis I: Introduction01:21

Myocarditis I: Introduction

Myocarditis is inflammation of the myocardium, which is the muscular layer of the heart.EtiologyMyocarditis has a diverse etiology, including a wide range of infectious and non-infectious causes:Infectious CausesViral: Common viruses include Coxsackie A and B, adenovirus, parvovirus B19, enteroviruses, and influenza A.Bacterial: Examples include infections caused by Streptococcus, Staphylococcus, and Mycoplasma species.Rickettsial: Infections like Rocky Mountain spotted fever can result in...
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,...
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...
Cardiomyopathy IV: Restrictive Cardiomyopathy01:29

Cardiomyopathy IV: Restrictive Cardiomyopathy

Restrictive cardiomyopathy (RCM) is a rare heart muscle disease characterized by impaired ventricular filling due to stiffened ventricular walls, leading to significant diastolic dysfunction.EtiologyRestrictive cardiomyopathy can arise from both inherited and acquired diseases, many of which are systemic. It is categorized into four main types: infiltrative, storage, non-infiltrative, and endomyocardial diseases.Infiltrative diseases, such as amyloidosis, lead to RCM by depositing amyloid...
Cardiomyopathy V: Interprofessional Care01:29

Cardiomyopathy V: Interprofessional Care

Managing cardiomyopathy involves addressing underlying or precipitating causes, treating heart failure with medications, and implementing dietary changes and a balanced exercise and rest regimen.Lifestyle ModificationsCardiomyopathy patients should adopt a low-sodium diet to reduce fluid retention and manage heart failure. A personalized exercise and rest plan helps maintain physical fitness without overstraining the heart. Avoiding alcohol and tobacco is essential to prevent further damage to...