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Conocimiento estructural sobre el mecanismo de autoinhibición de la proteína quinasa activada por AMP
Lei Chen1, Zhi-Hao Jiao, Li-Sha Zheng
1MOE Key Laboratory of Bioinformatics, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China.
Nature
|May 29, 2009
Resumen
La actividad de la proteína quinasa activada por AMP (AMPK) está regulada por la unión de AMP. Los estudios estructurales y bioquímicos revelan cómo el dominio autoinhibidor (AID) inhibe la AMPK y cómo la unión de la AMP la activa.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Molecular Biología Molecular
- El metabolismo celular es el metabolismo celular.
Sus antecedentes:
- La proteína quinasa activada por AMP (AMPK) regula la homeostasis de la energía celular mediante la detección de las relaciones ATP / AMP.
- La AMPK juega un papel crucial en el crecimiento celular, la proliferación y la polaridad, por lo que es un objetivo farmacológico clave para las enfermedades metabólicas y el cáncer.
- El mecanismo preciso por el cual la unión de AMP regula la actividad de AMPK ha permanecido elusivo.
Objetivo del estudio:
- Para aclarar la base estructural de la autoinhibición de AMPK y la activación por AMP.
- Para investigar el papel del dominio autoinhibidor (AID) en la regulación de la actividad de la quinasa.
- Comprender los cambios conformacionales subyacentes a la activación de la AMPK.
Principales métodos:
- Se utilizó cristalografía de rayos X para determinar las estructuras de un fragmento de subunidad alfa AMPK no fosforilada (KD-AID) y un dominio de quinasa fosforilada (Snf1-pKD).
- Se realizaron ensayos bioquímicos, incluidos estudios cinéticos in vitro, para evaluar la actividad de la quinasa y el efecto de las mutaciones.
- Se emplearon análisis estructurales para interpretar las interacciones entre el dominio de la quinasa y el dominio autoinhibidor.
Principales resultados:
- El dominio autoinhibidor (AID) se une a la región de bisagra del dominio de la quinasa, restringiendo la hélice alphaC y dando como resultado una actividad de la quinasa significativamente reducida.
- La interrupción de la interfaz KD-AID abolió la autoinhibición, haciendo que los mutantes AMPK no respondieran a los cambios en la concentración de AMP.
- Se demostró que la AMP activa la AMPK a través de mecanismos alostéricos y inhibiendo la desfosforilación.
Conclusiones:
- El estudio revela el mecanismo primario de la autoinhibición de la AMPK mediada por el AID.
- Se propone un modelo de conmutación conformacional para la activación de AMPK por AMP, que implica la liberación de la autoinhibición.
- Estos hallazgos proporcionan información crítica sobre la regulación de la AMPK y las posibles estrategias terapéuticas.
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