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Estructura de un dominio de enlace Ran complejo con Ran enlazado a un análogo GTP: implicaciones para el transporte

I R Vetter¹, C Nowak, T Nishimoto

¹Abteilung Strukturelle Biologie, Max-Planck-Institut für molekulare Physiologie, Dortmund, Germany.

|March 17, 1999

Resumen

La proteína Ran es la proteína Ran.

Área de la Ciencia:

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

Sus antecedentes:

La proteína Ran es una pequeña proteína de unión a GTP crucial para el transporte nuclear.
Ran interactúa con las proteínas de unión Ran y las moléculas similares a la importina-beta para regular los procesos celulares.
Los dominios de unión Ran (RanBD) son motivos conservados involucrados en estas interacciones.

Objetivo del estudio:

Para aclarar la base estructural de la interacción de Ran con RanBP2, un componente clave del complejo de poros nucleares.
Comprender el mecanismo por el cual los RanBDs regulan la actividad de la GTPasa de Ran y su papel en el transporte nuclear.

Principales métodos:

Se utilizó cristalografía de rayos X para determinar la estructura de Ran unido a un análogo de GTP (Ran x GppNHp) en complejo con el primer dominio de unión Ran (RanBD1) del RanBP2 humano.

Principales resultados:

RanBD1 comparte un pliegue de dominio de homología de pleckstrin.
La región switch-I de Ran x GppNHp se asemeja estructuralmente al Ras GppNHp canónico.
El terminal carboxínico de Ran se envuelve alrededor de RanBD1, formando un "abrazo" que secuestra el terminal y promueve la disociación de Ran de los factores de transporte.

Conclusiones:

Esta interacción representa un nuevo mecanismo de conmutación para las proteínas relacionadas con Ras.
La interacción Ran-RanBP2 facilita la hidrólisis de GTP por el ranGAP, regulando el transporte nuclear.
Este hallazgo proporciona nuevos conocimientos sobre la regulación de las interacciones proteína-proteína en el transporte celular.

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