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Automated Lipid Bilayer Membrane Formation Using a Polydimethylsiloxane Thin Film
Published on: July 10, 2016
Bid, Bax y los lípidos cooperan para formar aberturas supramoleculares en la membrana mitocondrial externa
Tomomi Kuwana1, Mason R Mackey, Guy Perkins
1La Jolla Institute for Allergy and Immunology, 10355 Science Center Drive, San Diego, CA 92121, USA.
Cell
|November 7, 2002
Resumen
Las proteínas de la familia Bcl-2 crean aberturas en la membrana mitocondrial externa, lo que permite una gran liberación de proteínas durante la apoptosis. Este proceso implica interacciones BH3/Bax/lípidos y es bloqueado por Bcl-x(L).
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología celular Biología celular.
- Biología Molecular Biología Molecular
Sus antecedentes:
- Las proteínas de la familia Bcl-2 son reguladores clave de la apoptosis.
- La permeabilización de la membrana externa mitocondrial (MOMP) es un paso crítico en la apoptosis, que conduce a la liberación de factores pro-apoptóticos.
- El mecanismo preciso de la MOMP y la translocación de proteínas grandes aún no se entiende por completo.
Objetivo del estudio:
- Para dilucidar el mecanismo molecular de la permeabilización de la membrana mitocondrial externa por las proteínas de la familia Bcl-2.
- Para determinar los componentes mínimos requeridos para la apertura de la membrana mediada por Bax.
- Investigar el papel de lípidos específicos y proteínas reguladoras en este proceso.
Principales métodos:
- Utilizó sistemas libres de células para estudiar las interacciones proteína-lípido.
- Se empleó la reconstitución vesicular a partir de moléculas definidas para imitar la membrana externa mitocondrial.
- Se evaluó la permeabilización de la membrana utilizando moléculas de dextrano grandes (2 megadaltones) para medir el tamaño de los poros.
Principales resultados:
- La permeabilización de la membrana externa por las proteínas Bcl-2 no requiere la matriz mitocondrial, la membrana interna u otras proteínas celulares.
- Bid o su péptido de dominio BH3 activaron el monómero Bax, formando aberturas de membrana lo suficientemente grandes como para el paso de dextrano de 2 megadaltones.
- La cardiolipina fue esencial para el proceso, y el anti-apoptótico Bcl-x(L) inhibió la activación de Bax y la permeabilización de la membrana.
Conclusiones:
- La liberación de proteínas mitocondriales durante la apoptosis está mediada por aberturas supramoleculares en la membrana mitocondrial externa.
- Estas aberturas son promovidas por la interacción de los péptidos del dominio BH3, Bax y cardiolipina.
- La proteína anti-apoptótica Bcl-x(L) inhibe directamente este proceso de permeabilización mediado por Bax.
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