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Conjunto helicoidal en el complejo MyD88-IRAK4-IRAK2 en la señalización TLR/IL-1R
Su-Chang Lin1, Yu-Chih Lo, Hao Wu
1Department of Biochemistry, Weill Cornell Medical College, New York, New York 10021, USA.
Nature
|May 21, 2010
Resumen
El complejo de dominio de muerte MyD88-IRAK4-IRAK2 forma una estructura helicoidal única, revelando cómo se inicia la señalización de receptores de tipo Toll. Este descubrimiento aclara el montaje y la regulación de las vías de señalización cruciales.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Biología Estructural Biología estructural.
- Inmunología Inmunología.
Sus antecedentes:
- La respuesta primaria de diferenciación mieloide 88 (MyD88), la quinasa asociada al receptor de la interleucina-1 4 (IRAK4) y IRAK2 son mediadores clave de la señalización.
- Estas proteínas son parte de la superfamilia del receptor Toll/interleucina-1 (TLR/IL-1R), crucial para la inmunidad innata.
Objetivo del estudio:
- Para determinar la estructura cristalina del complejo de dominio de muerte (DD) MyD88-IRAK4-IRAK2.
- Para aclarar el mecanismo de ensamblaje y los principios reguladores de los complejos Myddosome.
Principales métodos:
- Cristalografía de rayos X para determinar la estructura del complejo.
- Estudios de mutagenesis para confirmar los sitios de unión y las funciones funcionales.
- Análisis de mutaciones de señalización previamente identificadas.
Principales resultados:
- La estructura cristalina reveló un oligómero helicoidal zurdo compuesto por 6 dominios de muerte MyD88, 4 IRAK4 y 4 IRAK2.
- Se observó una asamblea jerárquica: MyD88 recluta a IRAK4, que luego recluta a IRAK2 o IRAK1.
- Los sitios de unión de los compuestos y la complementariedad electrostática rigen la especificidad y la estabilidad del complejo.
- La formación del midosoma reúne los dominios de la kinasa IRAK para su activación.
Conclusiones:
- El complejo MyD88-IRAK4-IRAK2 forma una "torre de señalización" esencial para la activación de la vía TLR/IL-1R.
- Esta estructura proporciona una plantilla para la señalización de Toll en Drosophila y destaca la versátil regulación de los complejos de dominio de muerte.
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