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Structural basis of cotranslational protein N-terminal acetylation by NatB in human cells.

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A molecular switch in NAC prevents mitochondrial protein mistargeting by SRP.

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NAC controls nascent chain fate through tunnel sensing and chaperone action.

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Mechanism of cotranslational modification of histones H2A and H4 by MetAP1 and NatD.

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Updated: Jun 15, 2025

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NAC guía un complejo multienzima ribosomal para el procesamiento de proteínas nacientes

Alfred M Lentzsch1, Denis Yudin2, Martin Gamerdinger3

  • 1Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA.

Nature
|August 21, 2024
PubMed
Resumen
Este resumen es generado por máquina.

El complejo polipéptido-asociado naciente (NAC) orquesta las modificaciones esenciales de las proteínas, la escisión de la metionina y la acetilación, mediante el ensamblaje de enzimas en los ribosomas. NAC asegura el procesamiento cotranslacional oportuno y activa la N-acetiltransferasa A (NatA) para una síntesis de proteínas eficiente.

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Área de la Ciencia:

  • Biología molecular
  • La bioquímica
  • Biología celular

Sus antecedentes:

  • ~40% de las proteínas de mamíferos se someten a la escisión y la acetilación de la metionina N-terminal.
  • Estas modificaciones son cotranslacionales y esenciales en las eucariotas.
  • Las interacciones enzimáticas y la regulación durante la traducción siguen sin estar claras.

Objetivo del estudio:

  • Para aclarar el papel del complejo asociado al polipéptido naciente (NAC) en la modificación de la proteína cotranslacional.
  • Investigar cómo el NAC interactúa con la metionina aminopeptidasa (MetAP) y la N-acetiltransferasa A (NatA).
  • Comprender la regulación de la actividad de NatA por NAC y la proteína K de levadura de huntingtina (HYPK).

Principales métodos:

  • Ensayos bioquímicos
  • Estudios de biología estructural
  • Experimentos en vivo

Principales resultados:

  • NAC forma un complejo multienzimático con MetAP1 y NatA en la traducción de los ribosomas.
  • NAC posiciona MetAP1 y NatA para el procesamiento secuencial de proteínas nacientes.
  • NAC libera la inhibición de HYPK para activar NatA, asegurando la acetilación cotranslacional.

Conclusiones:

  • El NAC actúa como un andamio para orquestar la escisión y la acetilación de la metionina cotranslacional N-terminal.
  • Se propone un modelo mecanicista para el procesamiento de proteínas asociadas a los ribosomas.
  • El NAC es crucial para la modificación eficiente y precisa de las proteínas cotranslacionales en eucariotas.