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Liberación regulada de L13a de la subunidad ribosómica 60S como mecanismo de control traslacional específico de
Barsanjit Mazumder1, Prabha Sampath, Vasudevan Seshadri
1Department of Cell Biology, Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
Cell
|October 22, 2003
Resumen
Un nuevo mecanismo de silenciamiento traslacional revela que la proteína ribosómica L13a, tras la fosforilación, se une al ARNm de ceruloplasmina.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Biología celular Biología celular.
- La bioquímica es la bioquímica.
Sus antecedentes:
- El control traslacional específico de transcripción se basa en proteínas que se unen a las regiones no traducidas (UTR) del ARNm.
- El sistema inhibidor de la traducción activado por interferón gamma (GAIT, por sus siglas en inglés) regula la expresión génica post-transcripcionalmente.
Objetivo del estudio:
- Para dilucidar un nuevo mecanismo de silenciamiento traslacional que involucra a la proteína ribosómica L13a.
- Para investigar el papel de L13a en la regulación de la traducción del ARNm de la ceruloplasmina (Cp).
Principales métodos:
- Cribado genético para identificar las proteínas de unión Cp 3'-UTR.
- En ensayos de traducción in vitro se utilizó L13a. recombinante.
- Estudios in vivo que involucran la estimulación de interferón-gamma y el análisis de la fosforilación de L13a y la liberación de subunidades ribosómicas.
Principales resultados:
- La proteína ribosómica humana L13a fue identificada como una GAIT del ARNm Cp.
- La L13a recombinante inhibió la traducción del ARNm Cp in vitro.
- El interferón gamma indujo la fosforilación de L13a y la liberación de la subunidad ribosómica 60S.
- La L13a liberada se une específicamente al elemento Cp mRNA 3'-UTR GAIT, silenciando la traducción.
Conclusiones:
- El ribosoma actúa como un depósito para las proteínas reguladoras que modulan la traducción.
- La liberación regulada de la proteína ribosómica L13a es un mecanismo clave para el silenciamiento traslacional.
- Este hallazgo expande las funciones conocidas de las proteínas ribosómicas más allá de la síntesis de proteínas.
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