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El canal de liberación de calcio del músculo esquelético: acoplado al sensor de O2 y las funciones de señalización de
1Howard Hughes Medical Institute, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA.
Cell
|August 31, 2000
Resumen
Los niveles de oxígeno en los tejidos regulan dinámicamente el canal de liberación de calcio del músculo esquelético (RyR1). El oxígeno bajo activa RyR1 a través del óxido nítrico (NO) y la S-nitrosilación, un proceso crucial para la función celular.
Área de la Ciencia:
- Fisiología Fisiología Fisiología.
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
Sus antecedentes:
- Los canales iónicos se estudian típicamente a niveles ambientales de oxígeno, pero la presión parcial de oxígeno en los tejidos fisiológicos (pO2) es significativamente menor.
- El canal de liberación de calcio del músculo esquelético / receptor de ryanodina (RyR1) es un canal iónico clave afectado por los niveles de oxígeno.
Objetivo del estudio:
- Investigar cómo los diferentes niveles de oxígeno (pO2) influyen en la función y regulación del canal RyR1.
- Explorar el papel del óxido nítrico (NO) y la S-nitrosilación en la modulación de RyR1 bajo condiciones fisiológicas pO2.
Principales métodos:
- Estudiar el estado redox de RyR1 y las modificaciones del tiol bajo diferentes condiciones de pO2.
- Investigando el efecto del NO nanomolar en la actividad de RyR1 y la S-nitrosilación a pO2.2. fisiológico.
- Evaluación de la especificidad de la S-nitrosilación entre las proteínas del retículo sarcoplásmico y el papel de la calmodulina.
Principales resultados:
- La presión parcial de oxígeno (pO2) controla dinámicamente el estado redox de 6-8 tiolos en cada subunidad RyR1.
- En la pO2 fisiológica, el óxido nítrico nanomolar (NO) activa RyR1 mediante la S-nitrosilación de un residuo específico de cisteína.
- La S-nitrosilación de RyR1 es específica entre las proteínas del retículo sarcoplásmico y su activación es dependiente de la calmodulina.
- La activación de RyR1 y la S-nitrosilación no ocurren en el ambiente pO2.
Conclusiones:
- Los residuos de cisteína en RyR1 actúan como sensores de oxígeno acoplados y reguladores de NO.
- El mecanismo de detección de oxígeno y regulación de NO observado en RyR1, que involucra a la calmodulina, puede aplicarse a otros sistemas biológicos relacionados con el redox.
- Comprender la regulación de RyR1 en la pO2 fisiológica es fundamental para comprender la función celular en entornos con bajo contenido de oxígeno.
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