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Síntasa de óxido nítrico compleja con distrofina y ausente del sarcolema del músculo esquelético en la distrofia
1Department of Physiology, University of California, San Francisco School of Medicine 94143-0444, USA.
Cell
|September 8, 1995
Resumen
La proteína distrofina ancla la sintasa de óxido nítrico neuronal (nNOS) a las membranas musculares, crucial para la función de las fibras de contracción rápida. La pérdida de este enlace en la distrofia muscular de Duchenne (DMD) puede explicar la degeneración de la fibra.
Área de la Ciencia:
- Fisiología muscular La fisiología muscular.
- Biología molecular La biología molecular.
- La bioquímica es la bioquímica.
Sus antecedentes:
- La sintasa de óxido nítrico de tipo neuronal (nNOS) sintetiza óxido nítrico (NO) en el músculo esquelético, principalmente en las fibras de contracción rápida.
- NO se ha demostrado que la síntesis en el músculo activo se oponga a la fuerza contráctil.
- La localización y regulación de nNOS en el músculo no se entiende completamente.
Objetivo del estudio:
- Investigar el papel de la distrofina en la localización y función de nNOS en el músculo esquelético.
- Para determinar si la asociación entre nNOS y la distrofina se altera en la distrofia muscular de Duchenne (DMD).
Principales métodos:
- Pruebas de inmunofluorescencia y bioquímicas para examinar la localización de nNOS en el músculo del ratón de tipo salvaje y mdx.
- Análisis de la proteína nNOS y la actividad catalítica en las membranas musculares.
- Investigación del dominio de interacción entre nNOS y el complejo de la distrofina.
Principales resultados:
- nNOS está localizado en el sarcolema de las fibras musculares esqueléticas de contracción rápida a través de su asociación con la distrofina.
- El complejo de distrofina interactúa con un dominio N-terminal de nNOS que contiene un motivo GLGF.
- Los músculos esqueléticos de ratones mdx y humanos con DMD muestran una pérdida selectiva de la proteína nNOS y la actividad catalítica de las membranas musculares.
Conclusiones:
- La distrofina juega un papel crítico en el anclaje de nNOS al sarcolema de los miocitos.
- La pérdida de nNOS de las membranas musculares en DMD sugiere una función novedosa para la distrofina en la localización de enzimas de señalización.
- La regulación aberrante de nNOS debido a la deficiencia de distrofina puede contribuir a la degeneración preferencial de las fibras musculares de contracción rápida observada en la DMD.
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