Effects of troponin T cardiomyopathy mutations on the calcium sensitivity of the regulated thin filament and the actomyosin cross-bridge kinetics of human ß-cardiac myosin.
PLoS One
; 8(12): e83403, 2013.
Article
em En
| MEDLINE
| ID: mdl-24367593
ABSTRACT
Hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) lead to significant cardiovascular morbidity and mortality worldwide. Mutations in the genes encoding the sarcomere, the force-generating unit in the cardiomyocyte, cause familial forms of both HCM and DCM. This study examines two HCM-causing (I79N, E163K) and two DCM-causing (R141W, R173W) mutations in the troponin T subunit of the troponin complex using human ß-cardiac myosin. Unlike earlier reports using various myosin constructs, we found that none of these mutations affect the maximal sliding velocities or maximal Ca(2+)-activated ADP release rates involving the thin filament human ß-cardiac myosin complex. Changes in Ca(2+) sensitivity using the human myosin isoform do, however, mimic changes seen previously with non-human myosin isoforms. Transient kinetic measurements show that these mutations alter the kinetics of Ca(2+) induced conformational changes in the regulatory thin filament proteins. These changes in calcium sensitivity are independent of active, cycling human ß-cardiac myosin.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Citoesqueleto de Actina
/
Actomiosina
/
Cálcio
/
Troponina T
/
Miosinas Ventriculares
/
Mutação
/
Cardiomiopatias
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Limite:
Adult
/
Humans
Idioma:
En
Revista:
PLoS One
Assunto da revista:
CIENCIA
/
MEDICINA
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Estados Unidos