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Spatiotemporal Control of Protein Activity through Optogenetic Allosteric Regulation
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Mecanismos estructurales y energéticos de autoinhibición cooperativa y activación de Vav1
Bingke Yu1, Ilídio R S Martins, Pilong Li
1Department of Biochemistry, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8816, USA.
Cell
|February 10, 2010
Resumen
Las proteínas Vav, los factores de intercambio de nucleótidos de guanina (GEF), están regulados por un elemento autoinhibidor. Los estudios estructurales y biofísicos revelan un mecanismo de activación gradual que involucra interacciones de dominio dependientes de la fosforilación para el control del GEF.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- La señalización celular de las células.
- Biología Estructural Biología estructural.
Sus antecedentes:
- Las proteínas Vav funcionan como factores de intercambio de nucleótidos de guanina (GEF) para las GTPasas de la familia Rho.
- Estos GEF son reguladores críticos de la activación de las células T, la fagocitosis y la migración celular.
- La desregulación de las proteínas Vav está implicada en varios procesos y enfermedades celulares.
Objetivo del estudio:
- Para dilucidar la estructura y el mecanismo autoinhibidor de la proteína Vav1.
- Comprender las bases biofísicas y celulares de la regulación de Vav1.
- Investigar cómo Vav1 logra tanto una fuerte autoinhibición como una activación rápida.
Principales métodos:
- Cristalografía de rayos X para determinar la estructura del elemento autoinhibidor Vav1.
- Técnicas biofísicas para analizar las interacciones de dominio y la energética.
- Pruebas celulares para evaluar la función de Vav1 y la cinética de activación.
Principales resultados:
- El elemento autoinhibidor de cinco dominios de Vav1 fue estructuralmente caracterizado.
- Se identificaron dos procesos acoplados energéticamente que controlan el dominio catalítico de la homología Dbl (DH).
- Se observó un alivio gradual de la autoinhibición, iniciado por eventos de fosforilación que interrumpen los contactos de dominio.
Conclusiones:
- La autoinhibición de Vav1 implica una interacción central entre los dominios DH y Acidic, reforzada por el dominio de homología de la calponina (CH).
- La interrupción dependiente de la fosforilación de los contactos del dominio CH facilita la activación posterior.
- Este mecanismo permite un control preciso de la actividad de Vav1, equilibrando la supresión y la activación rápida.
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