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In Vitro Analysis of PDZ-dependent CFTR Macromolecular Signaling Complexes
Published on: August 13, 2012
La fosforilación no logra activar los canales de cloruro de las células de las vías respiratorias de la fibrosis
R A Schoumacher1, R L Shoemaker, D R Halm
1Department of Pediatrics, University of Alabama, Birmingham 35294.
Nature
|December 24, 1987
Resumen
La fibrosis quística (FQ) afecta la función de los canales de cloruro en las células de las vías respiratorias. El defecto se encuentra en el canal.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Fisiología celular Fisiología celular.
- Enfermedades Genéticas Las enfermedades genéticas.
Sus antecedentes:
- La fibrosis quística (FQ) se caracteriza por la impermeabilidad del cloruro en las células epiteliales.
- La regulación defectuosa de los canales de cloruro (Cl-) de la membrana apical es un sello distintivo del epitelio de las vías respiratorias de la FQ.
- Los niveles de AMP cíclico celular (cAMP) aumentan normalmente en respuesta a los agonistas en las células de la FQ, pero la activación del canal se ve afectada.
Objetivo del estudio:
- Para investigar el defecto específico en la regulación del canal de cloruro mediada por cAMP en la fibrosis quística.
- Para localizar el defecto en las células epiteliales de las vías respiratorias de la FQ.
- Para determinar si el defecto reside en la vía de activación de la proteína quinasa A (PKA) o aguas abajo.
Principales métodos:
- Se utilizaron parches de membrana extirpados de células epiteliales de las vías respiratorias normales y CF.
- La superficie citoplasmática de estos parches fue expuesta a la subunidad catalítica (subunidad C) de la proteína quinasa dependiente de cAMP y ATP.
- Se midió la actividad de los canales de cloruro y se comparó entre las membranas normales y CF utilizando técnicas electrofisiológicas (activación inducida por voltaje y activación de la subunidad C).
Principales resultados:
- En las células normales, la subunidad C de la PKA activa los canales Cl-, imitando la estimulación del agonista dependiente de la cAMP.
- En las células CF, la subunidad C no pudo activar los canales Cl-, aunque los canales funcionales estaban presentes (verificado por la activación inducida por voltaje).
- Esto indica que el defecto está aguas abajo de la activación de PKA.
Conclusiones:
- El defecto de la fibrosis quística en la activación del canal de cloruro mediada por cAMP se encuentra distal a la activación de la proteína quinasa dependiente de cAMP.
- El estudio implica el propio canal de cloruro o sus proteínas reguladoras asociadas como el sitio primario del defecto en CF.
- Comprender este defecto molecular es crucial para desarrollar terapias dirigidas a la FQ.
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