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Estimulación de la función de activación RAR alfa AF-1 a través de la unión al factor de transcripción general TFIIH
C Rochette-Egly1, S Adam, M Rossignol
1Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Université Louis Pasteur, Collège de France, Illkirch, Strasbourg.
Cell
|July 11, 1997
Resumen
La actividad del receptor alfa del ácido retinoide (RAR alfa) depende de la fosforilación del Ser-77. La cinasa 7 dependiente de ciclina (CDK7) y el factor de transcripción TFIIH se unen y fosforilan el RAR alfa, mejorando su función de transactivación.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Reglamento genético Reglamento genético.
- La fosforilación de las proteínas.
Sus antecedentes:
- La función de activación del N-terminal AF-1 del receptor alfa del ácido retinoico (RAR alfa) es crucial para su actividad.
- La fosforilación de residuos específicos, como el Ser-77, puede modular la función del RAR alfa.
Objetivo del estudio:
- Para investigar el papel de la fosforilación del Ser-77 en la transactivación alfa del RAR.
- Para identificar las quinasas responsables de la fosforilación del Ser-77 in vivo e in vitro.
- Explorar la interacción entre RAR alfa y los factores generales de transcripción.
Principales métodos:
- Mutagénesis dirigida al sitio para crear un mutante S77A RAR.
- Ensayos de fosforilación in vitro utilizando RAR alfa recombinante y varias quinasas.
- Estudios de coexpresión in vivo para evaluar el efecto de cdk7 en la fosforilación y transactivación de Ser-77.
- Co-inmunoprecipitación para detectar la unión alfa de RAR con CAK y TFIIH.
Principales resultados:
- La mutación del Ser-77 abrogó la actividad del RAR alfa AF-1.
- La coexpresión de CDK7 mejoró la fosforilación de Ser-77 y la transactivación de RAR alfa in vivo.
- Tanto la kinasa activadora de CDK (CAK) libre como el Ser-77 fosforilado por TFIIH en vitro.
- RAR alfa se une directamente al CAK y al TFIIH.
Conclusiones:
- La fosforilación de Ser-77 por CDK7 es esencial para la transactivación de RAR alfa.
- RAR alfa interactúa con el factor de transcripción general TFIIH.
- Este estudio demuestra, por primera vez, la activación del transactivador a través de la unión y fosforilación por un factor de transcripción general.
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