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Movilización del factor de transcripción SPT23 procesado y atado a la membrana por CDC48 (UFD1/NPL4), una chaperona
1Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18a, 82152, Martinsried, Germany.
Cell
|December 6, 2001
Resumen
La vía OLE de la levadura utiliza el factor de transcripción SPT23, activado por el procesamiento regulado ubiquitina / proteosoma dependiente (RUP), para controlar la fluidez de la membrana. El complejo CDC48 ((UFD1/NPL4) libera selectivamente el SPT23 (p90) procesado para el objetivo nuclear.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Biología celular Biología celular.
- La bioquímica es la bioquímica.
Sus antecedentes:
- La vía OLE en la levadura regula la fluidez de la membrana mediante el control de la enzima Delta9-ácido graso desaturasa (OLE1) ligada a la ER.
- SPT23, un factor de transcripción y homólogo del NF-kappaB de los mamíferos, es un regulador clave en esta vía.
- SPT23 existe como un precursor inactivo anclado a la membrana ER, que requiere un procesamiento regulado ubiquitina / proteasoma dependiente (RUP) para la activación.
Objetivo del estudio:
- Para aclarar el mecanismo de activación de SPT23 y su posterior procesamiento y orientación nuclear.
- Investigar el papel de la dinámica del complejo proteico y la ubiquitinación en la regulación de SPT23.
- Para caracterizar la función del complejo CDC48 ((UFD1/NPL4) en el procesamiento de sustratos de proteínas ubiquitinadas.
Principales métodos:
- Análisis de la dimerización y procesamiento de SPT23.
- Investigación del estado de ubiquitinación de SPT23 durante la activación.
- Ensayos bioquímicos para estudiar la interacción entre SPT23, su forma procesada (p90) y el complejo CDC48 (UFD1/NPL4).
Principales resultados:
- SPT23 se dimeriza antes de someterse a un procesamiento regulado ubiquitina/proteasoma dependiente (RUP).
- La forma procesada, p90, inicialmente permanece unida al precursor SPT23 sin procesar a través de la modificación de la ubiquitina.
- El complejo de tipo chaperona CDC48 ((UFD1/NPL4) libera selectivamente p90 de su compañero para la translocación nuclear, lo que demuestra su preferencia por los sustratos ubiquitinados.
Conclusiones:
- La activación de SPT23 implica la dimerización y los pasos de procesamiento secuencial.
- La modificación de la ubiquitina juega un papel crucial en la unión del SPT23 (p90) procesado a su precursor.
- El complejo CDC48 ((UFD1/NPL4) actúa como un factor clave en la liberación selectiva de SPT23 ubiquitinado para su función, destacando su papel en el procesamiento de proteínas dependientes de la ubiquitina.
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