Video Experimental Relacionado
Updated: Jun 27, 2026
10:12
Measuring Endoplasmic Reticulum Stress and Unfolded Protein Response in HIV-1 Infected T-Cells and Analyzing its Role in HIV-1 Replication
Published on: June 14, 2024
Las mediciones de redox en tiempo real durante el estrés del retículo endoplasmático revelan funciones de plegamiento
Philip I Merksamer1, Ala Trusina, Feroz R Papa
1Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA.
Cell
|November 26, 2008
Resumen
Los investigadores desarrollaron nuevos métodos para medir el estado redox del retículo endoplasmático (ER), revelando que los cambios redox acompañan el estrés ER y las interrupciones del plegamiento de las proteínas. Este trabajo revela nuevos conocimientos sobre las respuestas celulares al estrés.
Área de la Ciencia:
- Biología celular Biología celular.
- La bioquímica es la bioquímica.
- Biología Molecular Biología Molecular
Sus antecedentes:
- El estrés del retículo endoplasmático (ER) ocurre cuando se acumulan proteínas desplegadas.
- La respuesta de la proteína desplegada (UPR) se activa para reducir las proteínas desplegadas.
- La medición directa de las proteínas desplegadas in vivo es un desafío, lo que lleva a definiciones genéricas de "estrés ER".
Objetivo del estudio:
- Investigar si los cambios de redox medibles acompañan la acumulación de proteínas desplegadas en el ER.
- Desarrollar herramientas para la medición dinámica del estado redox de ER y la actividad UPR en células individuales.
- Comprender la relación entre el potencial redox de ER, el plegamiento de proteínas y la activación de la UPR.
Principales métodos:
- Utilizó reporteros de proteínas fluorescentes para el monitoreo en tiempo real del estado redox de ER.
- Actividad de UPR medida en células individuales simultáneamente con el estado redox.
- Empleó análisis genético para estudiar las respuestas celulares a varios factores estresantes.
- Heterogeneidades redox investigadas dentro de poblaciones de células isogénicas.
Principales resultados:
- Diversos factores de estrés experimentales y fisiológicos comprometen la oxidación de la proteína ER cuando se pierde el control homeostático de la UPR.
- Se confirmó que los cambios redox están asociados con alteraciones en el plegamiento de la proteína ER.
- Descubiertos enlaces funcionales entre el plegamiento de proteínas ER, la modificación y los sistemas de control de calidad.
- Heterogeneidades redox identificadas en poblaciones celulares isogénicas.
Conclusiones:
- El estado redox de ER sirve como un indicador medible de la acumulación de proteínas desplegadas.
- El estudio proporciona un nuevo enfoque para evaluar el estrés de ER más allá de la activación genérica de UPR.
- Los hallazgos ponen de relieve la intrincada conexión entre el equilibrio redox y la homeostasis de proteínas en la ER.
Videos de Conceptos Relacionados
01:26Protein Modifications in the RER
Modification of secretory and transmembrane proteins entering the rough ER begins in the ER lumen. These modifications aid in protein folding and stabilize the acquired tertiary structure. Protein modifications in the rough ER co-occur at different stages of protein folding.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
01:31Regulation of the Unfolded Protein Response
Inositol-requiring kinase one or IRE1 is the most conserved eukaryotic unfolded protein response (UPR) receptor. It is a type I transmembrane protein kinase receptor with a distinctive site-specific RNase activity. As the binding mechanics of the misfolded proteins with the N-terminal domain of IRE-1 are unclear, three binding models — direct, indirect, and allosteric -- are proposed for receptor activation. Nevertheless, it is known that once a misfolded protein associates with IRE1, it...
01:37The Unfolded Protein Response
The ER is the hub of protein synthesis in a cell. It has robust systems to quality control protein folding and also for degradation of terminally misfolded proteins. Under normal conditions, a small proportion of misfolded proteins that cannot be salvaged need to be transported to the cytoplasm by the ER-associated degradation or ERAD pathways. However, if the ERAD cannot handle the misfolded proteins, the cell activates the unfolded protein response or UPR to adjust the protein folding...
01:29Protein Folding Quality Check in the RER
ER is the primary site for the maturation and folding of soluble and transmembrane secretory proteins. The calnexin cycle is a specific chaperone system that folds and assesses the confirmation of N-glycosylated proteins before they can exit the ER lumen. The primary players of this quality check pipeline are the lectins, ER-resident chaperones, and a glucosyl transferase enzyme. In case the calnexin system in the lumen fails to salvage a misfolded protein, it is transported to the cytoplasm...
01:32Export of Misfolded Proteins out of the ER
After folding, the ER assesses the quality of secretory and membrane proteins. The correctly folded proteins are cleared by the calnexin cycle for transport to their final destination, while misfolded proteins are held back in the ER lumen. The ER chaperones attempt to unfold and refold the misfolded proteins but sometimes fail to achieve the correct native conformation. Such terminally misfolded proteins are then exported to the cytosol by ER-associated degradation or ERAD pathway for...
01:19Protein Dynamics in Living Cells
Different fluorescence-based techniques are used to study the protein dynamics in living cells. These techniques include FRAP, FRET, and PET.
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...