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Las proteínas secretoras se mueven a través de la membrana del retículo endoplasmático a través de un poro acuoso y

K S Crowley¹, S Liao, V E Worrell

¹Department of Chemistry and Biochemistry, University of Oklahoma, Norman 73019.

|August 12, 1994

Resumen

Las proteínas secretoras se mueven a través de un poro acuoso que abarca la membrana ER durante la translocación cotranslacional. Este poro, inicialmente sellado desde el citoplasma, se abre solo después de que la cadena naciente alcanza aproximadamente 70 residuos.

Área de la Ciencia:

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

Sus antecedentes:

Las proteínas secretoras deben cruzar la membrana del retículo endoplasmático (ER).
El entorno preciso y la vía de la translocación de proteínas no se comprenden completamente.

Objetivo del estudio:

Para determinar el entorno de las proteínas secretoras nacientes durante la translocación a través de la membrana ER.
Para aclarar la naturaleza topográfica de la translocación cotranslacional.

Principales métodos:

Incorporación de sondas fluorescentes en las cadenas de polipéptidos nacientes durante la traducción.
Análisis de la vida útil de la fluorescencia de la sonda y el apagado de colisión por iones de yoduro.
Localización de las sondas dentro del ribosoma y a través de la bicapa de la membrana ER.

Principales resultados:

Las sondas dentro de la cadena naciente y el ribosoma indicaron consistentemente un entorno acuoso.
La cadena naciente ocupa un poro acuoso que abarca toda la membrana ER.
Este poro está sellado desde el citoplasma y se abre al lumen de ER solo después de que se sintetizan ~ 70 residuos.

Conclusiones:

Las proteínas secretoras nacientes se translocan a través de un poro acuoso continuo a través de la membrana ER.
La translocación cotranslacional topográfica es facilitada por este canal acuoso que abarca la membrana.
El mecanismo de apertura de los poros está regulado por la longitud de la cadena naciente.

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