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RNF168 ubiquitinates K13-15 en H2A / H2AX para impulsar la señalización de daño en el ADN
Francesca Mattiroli1, Joseph H A Vissers, Willem J van Dijk
1Division of Biochemistry and Center for Biomedical Genetics, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.
Cell
|September 18, 2012
Resumen
RNF168, no RNF8, monoubiquitinates histonas H2A / H2AX en K13-15 durante la respuesta al daño del ADN. Esta ubiquitinación específica de la histona, no sólo las cadenas de ubiquitina, es crucial para la señalización.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Biología celular Biología celular.
- La bioquímica es la bioquímica.
Sus antecedentes:
- La respuesta al daño del ADN (DDR) a las rupturas de doble cadena (DSB) implica una señalización dependiente de la ubiquitina.
- RNF8 y RNF168 son ligasas E3 clave que inician esta respuesta al dirigirse a las histonas H2A y H2AX.
Objetivo del estudio:
- Para aclarar los roles específicos de RNF8 y RNF168 en la ubiquitinación de histonas durante la DDR.
- Para determinar los sitios precisos de ubiquitinación y los enlaces de cadena involucrados en la señalización DSB.
Principales métodos:
- Mutagenesis basada en la estructura de los dominios RING RNF8 y RNF168.
- Análisis de los patrones de ubiquitinación de histonas (monoubiquitinación y cadenas ligadas a K63) en los sitios DSB.
- Evaluación funcional utilizando un mutante RNF168 incapaz de dirigirse a las histonas.
Principales resultados:
- RNF8 es inactivo hacia el H2A nucleosómico; RNF168 cataliza la monoubiquitinación H2A/H2AX en K13-15.
- Los residuos cargados en los dominios RING dictan el reconocimiento de proteínas nucleosómicas por RNF8/RNF168.8.
- Las cadenas de ubiquitina K63 están conjugadas con la monoubiquitinación dependiente de RNF168 en K13-15, no en K118-119.
- La capacidad de RNF168 para dirigirse a las histonas, no solo para catalizar las cadenas de ubiquitina, es esencial para la señalización DDR.
Conclusiones:
- RNF168 es la ligasa E3 primaria responsable de la monoubiquitinación H2A/H2AX en K13-15 durante la reparación del DSB.
- La ubiquitinación específica de la histona por RNF168 es un requisito previo para la señalización DDR aguas abajo, independiente de la formación de la cadena de ubiquitina sola.
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