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In Vitro Ubiquitination and Deubiquitination Assays of Nucleosomal Histones
Published on: July 25, 2019
Control de la homeostasis del hierro por una ubiquitina ligasa regulada por el hierro
Ajay A Vashisht1, Kimberly B Zumbrennen, Xinhua Huang
1Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
Science (New York, N.Y.)
|September 19, 2009
Resumen
La regulación del hierro en las células eucariotas implica la degradación de la proteína reguladora del hierro 2 (IRP2). Los investigadores identificaron el complejo SKP1-CUL1-FBXL5 como la E3 ubiquitina ligasa responsable de la proteólisis IRP2, que vincula los niveles de hierro con la estabilidad de las proteínas.
Área de la Ciencia:
- Biología celular Biología celular.
- Mecanismos moleculares de la homeostasis del hierro
Sus antecedentes:
- Las células eucariotas dependen del hierro, lo que requiere una regulación estricta de las concentraciones intracelulares.
- La degradación de la proteína reguladora del hierro 2 (IRP2) en las células repletas de hierro es crucial para la homeostasis del hierro, pero se desconoce la ligasa E3 ubiquitina responsable.
Objetivo del estudio:
- Para identificar la ubiquitina ligasa E3 responsable de la proteólisis de la proteína reguladora del hierro 2 (IRP2).
- Para aclarar el mecanismo por el cual los niveles de hierro intracelular regulan la degradación de IRP2.
Principales métodos:
- Los ensayos de coinmunoprecipitación identifican las interacciones de las proteínas.
- Ensayos de ubiquitinación y degradación in vitro.
- Análisis de la estabilidad de las proteínas en condiciones variables de hierro y oxígeno.
Principales resultados:
- Se encontró que el complejo de ubiquitina ligasa SKP1-CUL1-FBXL5 se asocia con IRP2.2.
- Este complejo promueve la ubiquitinación dependiente del hierro y la degradación de IRP2.
- La estabilidad de la proteína FBXL5 está regulada por los niveles intracelulares de hierro a través de un dominio de unión al hierro N-terminal.
Conclusiones:
- El complejo SKP1-CUL1-FBXL5 actúa como la E3 ubiquitina ligasa para la degradación de IRP2.
- La homeostasis del hierro se mantiene a través de una vía proteolítica que vincula la degradación de IRP2 a los niveles de hierro intracelular a través de la estabilidad y actividad de FBXL5.
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