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Un mecanismo de interruptor de palmitoilación en la regulación del ciclo visual
Linlong Xue1, Deviprasad R Gollapalli, Pranab Maiti
1Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 45 Shattuck Street, Boston, MA 02115, USA.
Cell
|June 10, 2004
Resumen
La proteína 65 del epitelio pigmentario de la retina (RPE65) tiene dos formas: asociada a la membrana (mRPE65) y soluble (sRPE65). Los controles de la palmitoilación son RPE6565 y RPE65.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Molecular Biología Molecular
- Visión Visión Ciencia Ciencia.
Sus antecedentes:
- La proteína 65 del epitelio del pigmento retiniano (RPE65) es crucial para la síntesis de 11-cis-retinal, el cromóforo de la rodopsina.
- El ciclo visual se basa en el procesamiento adecuado de los retinoides para la visión.
- Comprender la función de RPE65 es clave para abordar los trastornos de la visión relacionados con el metabolismo de los retinoides.
Objetivo del estudio:
- Aclarar las distintas funciones de las formas de RPE65 asociadas a la membrana (mRPE65) y solubles (sRPE65) de RPE65.
- Para investigar la función de la palmitoilación de RPE65 en el control de la unión a los retinoides.
- Para definir el papel de la lecitina retinol acil transferasa (LRAT) en la regulación de la actividad RPE65.
Principales métodos:
- Caracterización del estado de palmitoilación de RPE65.
- Análisis de la especificidad de unión de ligando para diferentes formas de RPE65.
- Investigando la actividad enzimática de LRAT en la interconversión de RPE65.
Principales resultados:
- El RPE65 asociado a la membrana (mRPE65) está triplemente palmitolizado y las chaperonas son todos los ésteres trans-retinilo.
- El RPE65 soluble (sRPE65) no está palmitoilado y acompaña a la vitamina A.
- La lecitina retinol acil transferasa (LRAT) actúa como un interruptor molecular, convirtiendo el mRPE65 en sRPE65 y controlando la síntesis de cromóforos.
- El RPE65 palmitoilado funciona como un donante de palmitoilo, lo que indica una nueva función de la proteína portadora de acilo.
Conclusiones:
- La palmitoilación de RPE65 dicta su selectividad de unión al ligando, diferenciando sus roles en el ciclo visual.
- LRAT funciona como una palmitoiltransferasa, catalizando la conversión entre mRPE65 y sRPE65, regulando así la síntesis de cromóforos.
- Las proteínas palmitoiladas pueden actuar como interruptores moleculares, con mRPE65 como un ejemplo clave en el metabolismo de los retinoides.
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