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Fosforilación del factor de transcripción PHO4 por un complejo ciclina-CDK, PHO80-PHO85
A Kaffman1, I Herskowitz, R Tjian
1School of Medicine, Department of Biochemistry and Biophysics, University of California at San Francisco 94143.
Science (New York, N.Y.)
|February 25, 1994
Resumen
Los investigadores descubrieron un complejo de quinasa dependiente de la ciclina, PHO80-PHO85, que regula la transcripción del gen PHO5 de la levadura mediante la fosforilación del factor de transcripción PHO4. Este hallazgo revela un nuevo papel para los complejos ciclina-cdk más allá del control del ciclo celular.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Genética de la levadura Genética de la levadura
- Regulación genética Reglamento genético.
Sus antecedentes:
- La transcripción del gen PHO5 de la levadura es activada por los factores de transcripción PHO2 y PHO4.
- La transcripción de PHO5 es reprimida bajo condiciones de alto fosfato por PHO80 y PHO85, que se cree que inactivan PHO2 y PHO4.
Objetivo del estudio:
- Investigar el mecanismo por el cual PHO80 y PHO85 regulan negativamente la transcripción de PHO5.
- Caracterizar la interacción entre PHO80 y PHO85 y su papel en la regulación de PHO4.
Principales métodos:
- Análisis de homología de PHO80.
- Estudios de interacción proteína-proteína entre PHO80 y PHO85.
- Ensayos de fosforilación in vitro de PHO4 por el complejo PHO80-PHO85.
Principales resultados:
- PHO80 exhibe homología a las ciclinas de levadura.
- PHO80 interactúa con PHO85, una proteína quinasa relacionada con el p34cdc2/CDC28.
- El complejo PHO80-PHO85 fosforila el PHO4.
- La fosforilación de PHO4 se correlaciona con la regulación negativa de la transcripción de PHO5.
Conclusiones:
- Un nuevo complejo de quinasa dependiente de ciclina (CDK), PHO80-PHO85, regula la transcripción génica fuera del control del ciclo celular.
- PHO4 es un sustrato fisiológicamente relevante para el complejo PHO80-PHO85 CDK.
- Este estudio aclara una nueva vía reguladora para la expresión del gen PHO5 en la levadura.
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