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Properties of Cardiac Myosin with Cardiomyopathic Mutations in Essential Light Chains

Daria S Yampolskaya1, Galina V Kopylova2, Daniil V Shchepkin2

  • 1Bach Institute of Biochemistry, Biotechnology Research Center, Russian Academy of Sciences, Moscow, 119071, Russia.

Biochemistry. Biokhimiia
|December 12, 2022
PubMed

Insights

Cardiomyopathy mutations in the MYL3 gene affect cardiac myosin function differently. While some mutations alter actin-myosin interactions, impacting muscle contraction, their precise mechanisms vary.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Cardiovascular Research

Background:

  • Hypertrophic cardiomyopathy is linked to mutations in cardiac myosin genes.
  • The essential light chain of ventricular myosin (ELCv) plays a crucial role in cardiac muscle function.
  • Understanding the impact of specific mutations on myosin function is key to elucidating disease mechanisms.

Purpose of the Study:

  • To investigate the functional consequences of cardiomyopathic mutations (E56G, M149V, E177G) in the MYL3 gene on human ventricular myosin (ELCv).
  • To determine how these mutations affect the actin-myosin interaction at the level of myosin subfragment 1 (S1) and in an in vitro motility assay.

Main Methods:

  • Investigated the actin-activated ATPase activity of isolated myosin subfragment 1 (S1).
  • Utilized an in vitro motility assay to assess the Ca2+-sensitivity and sliding velocity of thin filaments on immobilized myosin.
  • Examined the effects on regulated thin filaments and F-actin filaments.

Main Results:

  • The M149V mutation uniquely increased the actin-activated ATPase activity of S1.
  • All studied mutations significantly enhanced the Ca2+-sensitivity of sliding velocity.
  • Mutations E56G and M149V markedly reduced sliding velocity, while E177G did not.

Conclusions:

  • Despite all mutations being associated with hypertrophic cardiomyopathy, they exert distinct effects on actin-myosin interactions.
  • The findings highlight diverse molecular mechanisms underlying ELCv-related cardiomyopathies.
  • This study provides insights into the structure-function relationships of cardiac myosin.

Keywords:
cardiac musclecardiomyopathic mutationsessential light chainsmolecular mechanism of muscle contractionmyosin

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