Video Experimental Relacionado
Updated: May 5, 2026
10:24
Visualization of Endoplasmic Reticulum Localized mRNAs in Mammalian Cells
Published on: December 17, 2012
13.5K
El ARN mensajero se dirige a los sitios de señalización de estrés del retículo endoplasmático
Tomás Aragón1, Eelco van Anken, David Pincus
1Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94158-2517, USA. Tomas.Aragon@ucsf.edu
Nature
|December 17, 2008
Resumen
El estrés en el retículo endoplasmático (ER) desencadena la respuesta proteica desplegada (UPR). La activación de Ire1 hace que el ARNm unido a ER se agrupe, lo que permite la señalización de la UPR y la regulación del plegamiento de las proteínas.
Área de la Ciencia:
- Biología celular Biología celular.
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
Sus antecedentes:
- El estrés del retículo endoplasmático (ER) surge del mal plegamiento de la proteína, activando la respuesta de la proteína desplegada (UPR).
- El UPR está mediado por sensores como Ire1, que empalman el ARNm HAC1 (levadura) o XBP1 (metazoos) para restaurar la homeostasis ER.
- El control traslacional del ARNm HAC1 por su intrón y 5' UTR regula la síntesis de Hac1.
Objetivo del estudio:
- Investigar el mecanismo molecular de la activación de Ire1 y el empalme de ARNm HAC1 durante la RPU.
- Para aclarar cómo Ire1 agrupación y reclutamiento de ARNm contribuyen a la señalización UPR.
- Para identificar el papel de los elementos conservados en la orientación del ARNm HAC1.
Principales métodos:
- Genética de la levadura y técnicas de biología molecular.
- Análisis de la oligomerización y localización de Ire1 utilizando microscopía.
- Estudios de interacción mRNA-proteína y ensayos funcionales.
Principales resultados:
- La activación de Ire1 conduce a su agrupación en focos discretos de la membrana ER, formando oligómeros de orden superior.
- El ARNm HAC1 no esplicado es reclutado a estos focos Ire1 a través de un elemento bipartito en su 3' UTR.
- La interrupción de la agrupación de Ire1 o el reclutamiento de ARNm perjudica significativamente la señalización de la UPR.
- El elemento HAC1 3' UTR puede dirigirse a otros ARNm reprimidos hacia focos Ire1.
Conclusiones:
- El reclutamiento de ARNm a los centros de señalización de Ire1 es un nuevo mecanismo para controlar la expresión génica eucariota.
- Este proceso es crucial para la activación eficiente de la UPR y la adaptación celular al estrés ER.
- Los hallazgos revelan un nuevo paradigma en la regulación de la expresión génica en la membrana ER.
Más Videos Relacionados
Videos de Conceptos Relacionados
02:22Regulated mRNA Transport
5.7K
In eukaryotes, transcription and translation are compartmentalized; an mRNA is first synthesized in the nucleus and then selectively transported to the cytoplasm for protein synthesis. Before transport, a pre-mRNA undergoes several steps of post-transcriptional modifications including splicing, 5' capping, and the addition of a poly-adenine tail. Various proteins bind to the pre-mRNA during these modifications. The mRNA transport takes place with the help of multiple proteins playing...
5.7K
01:17Role of ER in the Secretory Pathway
6.3K
Eukaryotic cells have a special pathway that enables communication between various intracellular membrane-bound compartments and also with the extracellular environment. This pathway is termed as the secretory pathway.
Components of the secretory pathway
About a third of proteins synthesized in the cell are sorted via the secretory route. They shuffle between different compartments in membrane-bound vesicles until they reach their final destination. The main intracellular compartments involved...
Components of the secretory pathway
About a third of proteins synthesized in the cell are sorted via the secretory route. They shuffle between different compartments in membrane-bound vesicles until they reach their final destination. The main intracellular compartments involved...
6.3K
01:34Directing Proteins to the Rough Endoplasmic Reticulum
12.0K
The organelle-specific signaling sequences direct proteins synthesized in the cytosol to their final destination like ER, mitochondria, peroxisomes, etc. Some of the proteins directed to ER are then trafficked via vesicles to other organelles within the cell or the extracellular environment through the Golgi complex. For example, the rough ER synthesizes soluble proteins for transportation to the lysosomes or secretion out of the cell. It can also synthesize transmembrane proteins that can...
12.0K
01:37The Unfolded Protein Response
5.6K
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...
5.6K
01:32Export of Misfolded Proteins out of the ER
4.3K
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...
4.3K
01:31Regulation of the Unfolded Protein Response
2.2K
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...
2.2K