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Regulación dual del complejo de la proteína quinasa de la levadura CDC28-p40: ciclo celular, feromonas y efectos de
Cell
|September 11, 1987
Resumen
La progresión del ciclo celular depende de la actividad de la cinasa CDC28, que es específica de la fase G1. La actividad se pierde al entrar en la fase S o el apareamiento, lo que indica la necesidad de un factor de activación.
Área de la Ciencia:
- Biología celular Biología celular.
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
Sus antecedentes:
- El producto del gen CDC28 es un regulador clave del ciclo celular en la levadura.
- Se sabe que un polipéptido de 40 kDa se asocia con el producto del gen CDC28.
Objetivo del estudio:
- Para investigar la regulación de la actividad de la proteína quinasa CDC28 durante el ciclo celular.
- Para identificar los factores que controlan la fosforilación específica del polipéptido de 40 kDa.
Principales métodos:
- Precipitación del complejo inmune para aislar el producto genético CDC28.
- Ensayos de kinasa in vitro para medir la fosforilación del polipéptido de 40 kDa.
- Los ensayos de complementación utilizan extractos de diferentes fases del ciclo celular y mutantes.
Principales resultados:
- La actividad de la proteína quinasa CDC28, medida por la fosforilación p40, se detecta exclusivamente en las células en fase G1 que se dividen.
- La actividad se pierde cuando las células salen de G1 para entrar en la fase S o en el estado preconjugado.
- Los extractos de células no G1 son deficientes en un factor de activación intercambiable, mientras que las células estacionarias y tratadas con feromonas contienen este factor pero tienen una quinasa inactiva.
- Los mutantes con deficiencia de cAMP exhiben características similares a las de las células estacionarias.
Conclusiones:
- La actividad de la proteína quinasa CDC28 está estrictamente regulada y restringida a la fase G1 del ciclo celular.
- La progresión del ciclo celular está controlada por la presencia y actividad de un factor activador intercambiable para la quinasa CDC28.
- La regulación de esta quinasa es crucial para evitar la entrada en la fase S o el apareamiento en condiciones inadecuadas.
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