Represión de la actividad de mTORC1 por el fosfatidilinositol endosómico tardío 3,4-bisfosfato
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Ver abstracta en PubMed
Resumen
Este resumen es generado por máquina.El fosfatidilinositol 3,4-bisfosfato [PI(3,4) P2], producido por PI3KC2β, actúa como un nuevo inhibidor de la vía del objetivo mecanicista del complejo de rapamicina 1 (mTORC1). Este hallazgo revela un nuevo mecanismo para controlar el crecimiento celular durante la privación de nutrientes.
Área De La Ciencia
- Biología celular
- Biología molecular
- La bioquímica
Sus Antecedentes
- El objetivo mecánico del complejo de rapamicina 1 (mTORC1) regula el crecimiento celular y es activado por los nutrientes.
- Las fosfatidilinositol 3-cinasas (PI3K) de clase I en la membrana plasmática estimulan el mTORC1 a través de la producción de fosfatidilinositol 3,4,5-trisfosfato [PI(3,4,5) P3].
Objetivo Del Estudio
- Investigar los mecanismos que reprimen la actividad de mTORC1 durante la privación del factor de crecimiento.
- Identificar nuevos reguladores de la señalización de mTORC1 en los lisosomas y los endosomas tardíos (LyLEs).
Principales Métodos
- Investigó el papel de la clase II PI3K β (PI3KC2β) y su producto, el fosfatidilinositol 3,4-bisfosfato [PI(3,4) P2], en la regulación de mTORC1.
- Se utilizaron técnicas para evaluar la actividad de mTORC1, las interacciones proteína-proteína y la localización de lípidos.
Principales Resultados
- Identificado PI(3,4) P2, sintetizado por PI3KC2β en LyLEs, como un regulador negativo de mTORC1.
- Se ha observado una hiperactivación de mTORC1 en células que carecen de PI3KC2β.
- Se demostró que la privación del factor de crecimiento induce la asociación de PI3KC2β con la subunidad Raptor de mTORC1.
- Se demostró que la síntesis local de PI(3,4) P2 promueve la unión de Raptor a las proteínas inhibidoras 14-3-3, reprimiendo mTORC1.
Conclusiones
- La síntesis local de PI2 mediada por PI3KC2 es un mecanismo clave para apagar mTORC1.
- Esta vía proporciona una ruta inesperada para reprimir la señalización de mTORC1 en condiciones de escasez de nutrientes o factores de crecimiento.
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