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MOM19, un receptor de importación para las proteínas precursoras mitocondriales

T Söllner¹, G Griffiths, R Pfaller

¹Institut für Physiologische Chemie, Universität München, Federal Republic of Germany.

|December 22, 1989

Resumen

Los investigadores identificaron MOM19, una proteína de la membrana externa mitocondrial. Los anticuerpos contra MOM19 bloquean la importación de muchas proteínas precursoras en las mitocondrias, lo que sugiere que MOM19 es un receptor de importación clave.

Área de la Ciencia:

Biología mitocondrial Biología mitocondrial
La importación de proteínas es importante.
Biología celular y molecular Biología celular y molecular.

Sus antecedentes:

Las mitocondrias importan numerosas proteínas para llevar a cabo sus funciones.
Los mecanismos y los receptores específicos involucrados en la importación de proteínas mitocondriales no están completamente esclarecidos.
Estudios previos sugirieron distintas vías de importación para diferentes proteínas mitocondriales.

Objetivo del estudio:

Para identificar y caracterizar las proteínas involucradas en el proceso de importación de proteínas mitocondriales.
Para investigar el papel de una proteína recién identificada de 19 kd de la membrana externa mitocondrial (MOM19) en la importación de proteínas.
Para determinar si MOM19 funciona como un receptor de importación mitocondrial específico.

Principales métodos:

Identificación de una proteína 19 kd en la membrana externa de las mitocondrias (MOM19).
Se utilizaron fragmentos monospecíficos de IgG y Fab contra MOM19.
Evaluó el efecto de estos anticuerpos en la importación de varias proteínas precursoras en las mitocondrias.
Analizó la afinidad de unión de los precursores a las mitocondrias.

Principales resultados:

Los anticuerpos monospecíficos contra MOM19 inhibieron la importación de proteínas precursoras para múltiples subcompartimentos mitocondriales.
La inhibición se produjo en la etapa de unión del precursor de alta afinidad a las mitocondrias.
La importación de portadores de ADP/ATP y precursores del citocromo c no fue inhibida, alineándose con distintas hipótesis del sitio de importación.
MOM19 está implicado en la vía de importación de un subconjunto de proteínas mitocondriales.

Conclusiones:

MOM19 es un componente crítico de la maquinaria de importación de proteínas mitocondriales.
MOM19 funciona como, o está estrechamente asociado con, un receptor específico para la importación mitocondrial.
Los hallazgos apoyan la existencia de distintas vías de importación mediadas por receptores específicos como el MOM19.

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