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Estructura del complejo de transporte nuclear carioferina-beta2-Ran x GppNHp

Y M Chook¹, G Blobel

¹Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, New York 10021, USA.

|June 3, 1999

Resumen

La estructura de la carioferina-beta2 (transportina) revela cómo se une a la carga e interactúa con Ran GTP para facilitar el transporte nuclear. Esto proporciona información sobre la especificidad de las proteínas caryopherin-beta para el estado GTP-unido de Ran.

Área de la Ciencia:

Biología Molecular Biología Molecular
Biología Estructural Biología estructural.
Biología celular Biología celular.

Sus antecedentes:

Las proteínas carioferina-beta son cruciales para el transporte nuclear-citoplasmático.
Karyopherin-beta2 (transportin) se une específicamente a los sustratos de importación e interactúa con Ran GTP para liberar la carga en el núcleo.

Objetivo del estudio:

Determinar la estructura de 3,0 Å del complejo carioferina-beta2-Ran x GppNHp.
Para aclarar la base estructural para la unión al sustrato y la disociación mediada por Ran GTP.

Principales métodos:

Cristalografía de rayos X del complejo karioferina-beta2-Ran x GppNHp.
Análisis estructural de las interacciones proteína-proteína.

Principales resultados:

La estructura revela que la carioferina-beta2 tiene dieciocho repeticiones HEAT formando dos arcos.
Ran GTP se une en el arco amino-terminal, mientras que la unión al sustrato se produce en el arco carboxiterminal.
Un bucle en la repetición 7 de HEAT media las interacciones entre Ran y el arco carboxiterminal, crucial para la disociación del sustrato.

Conclusiones:

La estructura proporciona una base molecular para la función de la carioferina-beta2 en el transporte nuclear.
Explica la especificidad de Ran GTP y las interacciones con proteínas reguladoras como ranGAP, ranGEF y ranBP1.

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