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La translocación de oligosacáridos ligados a lípidos a través de la membrana ER requiere la proteína Rft1 de la

Jonne Helenius¹, Davis T W Ng, Cristina L Marolda

¹Institute of Microbiology, Swiss Federal Institute of Technology, Zürich, CH-8092 Zürich, Switzerland.

|January 25, 2002

Resumen

Los investigadores identificaron la proteína RFT1 en la levadura como esencial para la translocación de un precursor clave de azúcar-proteína a través de la membrana del retículo endoplasmático. Este descubrimiento arroja luz sobre la vía de glicosilación ligada a N conservada en las células eucariotas.

Área de la Ciencia:

La bioquímica es la bioquímica.
Biología Molecular Biología Molecular
Biología celular Biología celular.

Sus antecedentes:

La glicosilación ligada a N es una vía crítica y conservada en las células eucariotas para la modificación de proteínas.
El proceso consiste en ensamblar un tetradecasacárido (Glc3Man9GlcNAc2) en un portador de dolicol-fosfato dentro del retículo endoplasmático (ER).
La translocación de los intermediarios de oligosacáridos ligados a lípidos a través de la membrana ER es esencial, pero las proteínas involucradas (flippases) seguían siendo escurridizas.

Objetivo del estudio:

Para identificar la proteína responsable del movimiento transmembrana del intermediario Man5GlcNAc2-PP-Dol.
Para investigar el papel de esta proteína en la vía de glicosilación ligada a N.

Principales métodos:

Utilizó la levadura como organismo modelo.
Investigó la función del gen RFT1 y su proteína codificada.

Principales resultados:

Proporcionó evidencia de que la levadura RFT1 codifica una proteína esencial para la translocación de Man5GlcNAc2-PP-Dol.
Se demostró que se requiere RFT1 para mover el intermediario de oligosacáridos del citoplasma al lado luminal de la membrana ER.
Indicó que RFT1 es una proteína conservada evolutivamente.

Conclusiones:

RFT1 es la esquiva flippase que cataliza el paso de translocación esencial en la glicosilación ligada a N.
Este hallazgo avanza nuestra comprensión de un proceso celular fundamental con implicaciones para varios tipos de células.

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