Mutations of ventricular essential myosin light chain disturb myosin binding and sarcomeric sorting.
Cardiovasc Res
; 93(3): 390-6, 2012 Mar 01.
Article
em En
| MEDLINE
| ID: mdl-22131351
ABSTRACT
AIMS:
We tested the hypothesis that mutations in the human ventricular essential myosin light chain (hVLC-1) that are associated with hypertrophic cardiomyopathy (HCM) affect protein structure, binding to the IQ1 motif of cardiac myosin heavy chain (MYH) and sarcomeric sorting in neonatal cardiomyocytes. METHODS ANDRESULTS:
We employed circular dichroism and surface plasmon resonance spectroscopy to investigate structural properties and protein-protein interactions of a recombinant head-rod fragment of rat cardiac ß-MYH (amino acids 664-915) with alanine-mutated IQ2 domain (rß-MYH(664-915)IQ2(ala4)) and normal or five mutated (M149V, E143K, A57G, E56G, R154H) hVLC-1 forms. Double epitope-tagging competition was used to monitor the intracellular localization of exogenously introduced normal and E56G-mutated (hVLC-1(E56G)) hVLC-1 constructs in neonatal rat cardiomyocytes. Fluorescence lifetime imaging microscopy was applied to map the microenvironment of normal and E56G-mutated hVLC-1 in permeabilized muscle fibres. Affinity of M149V, E143K, A57G, and R154H mutated hVLC-1/rß-MYH(664-915)IQ2(ala4) complexes was significantly lower compared with the normal hVLC-1/rß-MYH(664-915)IQ2(ala4) complex interaction. In particular, the E56G mutation induced an â¼30-fold lower MYH affinity. Sorting specificity of E56G-mutated hVLC-1 was negligible compared with normal hVLC-1. Fluorescence lifetime of fibres replaced with hVLC-1(E56G) increased significantly compared with hVLC-1-replaced fibres.CONCLUSION:
Disturbed myosin binding of mutated hVLC-1 may provide a pathomechanism for the development of HCM.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sarcômeros
/
Cardiomiopatia Hipertrófica
/
Cadeias Leves de Miosina
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Miócitos Cardíacos
Limite:
Animals
/
Humans
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article