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La escisión del enlace fosfodiéster fuera de las mitocondrias es necesaria para completar la importación de proteínas

W J Chen, M G Douglas

|June 5, 1987

Resumen

La importación de proteínas mitocondriales requiere un segundo paso: la hidrólisis del enlace fosfodiéster, probablemente a partir del ATP. Esta actividad dependiente del ATP ocurre fuera de la membrana interna, ayudando a la translocación de proteínas.

Área de la Ciencia:

Biología mitocondrial Biología mitocondrial
Mecanismos de importación de proteínas
La bioquímica es la bioquímica.

Sus antecedentes:

La importación de proteínas mitocondriales es crucial para la función celular.
La subunidad beta de la F1-ATPasa se importa a las mitocondrias a través de un proceso de varios pasos.
Estudios previos identificaron un primer paso dependiente del potencial de la membrana.

Objetivo del estudio:

Para dilucidar el distinto segundo paso en la importación mitocondrial de la subunidad beta de la F1-ATPasa.
Para identificar la ubicación y la naturaleza de la actividad que impulsa este segundo paso.
Para entender el mecanismo por el cual se completa la importación de proteínas.

Principales métodos:

Utilizó un inhibidor del transporte de nucleótidos de adenina.
Se empleó el análogo no hidrolizable del ATP, beta,gamma-AMP-PCP.
Investigó la ubicación de la actividad de finalización de la importación de proteínas.

Principales resultados:

La hidrólisis de un enlace fosfodiéster, probablemente ATP, es un segundo paso distinto para la finalización de la importación.
Este paso es independiente de la fase inicial dependiente del potencial de la membrana.
La actividad responsable se encuentra fuera de la membrana interna mitocondrial.

Conclusiones:

Un evento de hidrólisis de ATP posterior a la translocación es esencial para completar la importación de subunidades beta de la F1-ATPasa.
Esta actividad extramembrana puede facilitar la competencia precursora o la translocación directa.
La actividad de importación comparte características con las proteínas de choque térmico involucradas en el plegamiento de las proteínas.

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