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Los cuerpos de los polos de huso explotan la red de salida mitótica en la metafase para impulsar su segregación
Manuel Hotz1, Christian Leisner, Daici Chen
1Institute of Biochemistry, Biology Department, ETH Zurich, 8093 Zurich, Switzerland.
Cell
|March 6, 2012
Resumen
La levadura de brote asegura la división celular correcta al heredar asimétricamente los cuerpos de los polos del huso. La red de salida mitótica (MEN, por sus siglas en inglés) estabiliza la localización de Kar9 en el viejo cuerpo del polo del huso, asegurando una segregación adecuada durante la división celular.
Área de la Ciencia:
- Biología celular Biología celular.
- Biología Molecular Biología Molecular
- Genética La genética.
Sus antecedentes:
- La división celular asimétrica es crucial para la diferenciación celular y el desarrollo.
- En la levadura en ciernes, la segregación de los polos mitóticos del huso no es aleatoria, con el antiguo cuerpo del polo del huso (SPB) preferentemente heredado por la célula hija.
- Kar9 es una proteína clave que se acumula de manera asimétrica durante la metafase, localizándose en los microtúbulos astrales del viejo SPB para dirigir su segregación.
Objetivo del estudio:
- Investigar el papel de la red de salida mitótica (MEN) en la especificación de la herencia asimétrica de SPB en la levadura en ciernes.
- Aclarar el mecanismo por el cual se establece y mantiene la asimetría de Kar9.
- Para entender cómo la identidad de SPB está vinculada a la regulación de Kar9.
Principales métodos:
- Análisis genético de mutantes de levadura en ciernes que carecen de componentes de señalización MEN.
- Microscopía de inmunofluorescencia para visualizar la localización de Kar9 y la segregación de SPB.
- Ensayos bioquímicos para evaluar la fosforilación de Kar9 por las MEN quinasas Dbf2 y Dbf20.
Principales resultados:
- La vía de señalización de la red de salida mitótica (MEN) es esencial para especificar la herencia asimétrica de SPB.
- En ausencia de señalización MEN, la asimetría de Kar9 se vuelve inestable y su preferencia por el antiguo SPB se ve interrumpida.
- La fosforilación de Kar9 por Dbf2 y Dbf20 no es necesaria para romper la simetría de Kar9, pero es fundamental para mantener su asociación estable con el antiguo SPB a lo largo de la metafase.
Conclusiones:
- La señalización MEN es un regulador clave de la herencia asimétrica de SPB en la levadura en ciernes.
- La señalización MEN estabiliza la asociación de Kar9 con el antiguo SPB, asegurando su segregación adecuada.
- El estudio propone que la señalización MEN vincula la regulación de Kar9 a la identidad de SPB, estabilizando el mecanismo de ruptura de simetría.
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