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La inhibición de la señalización del factor de crecimiento transformador-beta/SMAD por la vía interferón-gamma/STAT
1Cell Biology Program and Howard Hughes Medical Institute, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
Nature
|March 6, 1999
Resumen
El interferón-gamma (IFN-gamma) inhibe la señalización transformadora del factor de crecimiento beta (TGF-beta) al inducir Smad7, que bloquea la activación de Smad3. Esto revela un diálogo cruzado entre las vías STAT y SMAD, explicando sus efectos celulares antagónicos.
Área de la Ciencia:
- Biología celular Biología celular.
- La señalización molecular.
- Inmunología Inmunología.
Sus antecedentes:
- El factor de crecimiento transformador-beta (TGF-beta) y el interferón-gamma (IFN-gamma) muestran efectos opuestos en las funciones celulares.
- Los mecanismos moleculares que subyacen a este antagonismo no se comprenden completamente.
- La señalización TGF-beta implica la fosforilación de Smad2 / 3, mientras que la señalización IFN-gamma activa Stat1 a través de Jak1.
Objetivo del estudio:
- Para dilucidar la base molecular de la interacción antagónica entre las vías de señalización TGF-beta e IFN-gamma.
- Para identificar el mecanismo que integra estas dos cascadas de transducción de señales distintas.
Principales métodos:
- Investigó los efectos de IFN-gamma en la fosforilación de Smad3 inducida por TGF-beta y los eventos posteriores.
- Analizó la asociación Smad3/Smad4, la translocación nuclear y la activación de genes.
- Se examinó el papel de Jak1/Stat1 en la inducción de la expresión de Smad7.
- Se evaluó la función de Smad7 en la prevención de la interacción de Smad3 con el receptor TGF-beta.
Principales resultados:
- El IFN-gamma inhibe la fosforilación Smad3 inducida por el TGF-beta.
- IFN-gamma bloquea la formación de complejos Smad3/Smad4, la acumulación nuclear y la activación del gen TGF-beta-responsivo.
- IFN-gamma, a través de Jak1 y Stat1, induce la expresión de Smad7.
- Smad7 impide que Smad3 interactúe con el receptor de TGF-beta, inhibiendo así la señalización de TGF-beta.
Conclusiones:
- IFN-gamma antagoniza la señalización de TGF-beta al inducir la expresión de Smad7 a través de la vía Jak1/Stat1.
- Este estudio revela un mecanismo de transmodulación entre las vías de transducción de señales STAT y SMAD.
- Los hallazgos proporcionan una base molecular para las funciones celulares opuestas de TGF-beta e IFN-gamma.
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