Video Experimental Relacionado
Updated: Aug 10, 2026
10:24
Visualization of Endoplasmic Reticulum Localized mRNAs in Mammalian Cells
Published on: December 17, 2012
La eliminación del dominio estructural Alu de la partícula de reconocimiento de señales deja intacta su actividad de
Nature
|March 6, 1986
Resumen
Los investigadores investigaron la función de las secuencias de tipo Alu dentro del ARN 7SL, un componente de la partícula de reconocimiento de señales (SRP). Descubrieron que la eliminación de estas secuencias y una proteína específica (9/14K) inhabilitó la detención de la síntesis de proteínas, pero no la translocación de proteínas.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Biología celular Biología celular.
- Genética La genética.
Sus antecedentes:
- Los elementos Alu-like son abundantes secuencias repetitivas en primates y roedores, probablemente derivadas de la transcripción inversa de transcripciones de ARN.
- Estos elementos comparten similitudes con el ARN 7SL, un componente crucial de la partícula de reconocimiento de señales (SRP) involucrada en la orientación de proteínas.
- SRP es un complejo de ribonucleoproteínas esencial para dirigir las proteínas secretoras y de membrana al retículo endoplasmático.
Objetivo del estudio:
- Determinar el papel específico de las secuencias de tipo Alu dentro del ARN 7SL en la actividad de la partícula de reconocimiento de señales (SRP).
- Investigar la contribución funcional del ARN Alu-like y las proteínas asociadas a los procesos mediados por SRP.
Principales métodos:
- Purificación y análisis de una subpartícula de partícula de reconocimiento de señales (SRP) que carece de secuencias de tipo Alu después de la digestión de la nucleasa del micrococo.
- Los ensayos de actividad in vitro evalúan la capacidad de la subpartícula para promover la translocación de proteínas secretoras y detener la síntesis de proteínas pre-secretoras.
- Análisis de la composición proteica de la SRP intacta y de la subpartícula derivada.
Principales resultados:
- La subpartícula SRP que carecía de secuencias de tipo Alu conservaba proteínas esenciales (72/68K, 54K, 19K) pero carecía de la proteína 9/14K.
- Esta subpartícula aún podría facilitar la translocación de proteínas secretoras a través de la membrana microsomal.
- Sin embargo, la subpartícula perdió la capacidad de detener la síntesis de proteínas pre-secretoras; volver a agregar la proteína 9/14K no restauró esta función.
Conclusiones:
- El ARN tipo Alu y la proteína 9/14K forman un dominio estructural distinto dentro de la partícula de reconocimiento de señales (SRP).
- Este dominio no es esencial para la translocación de proteínas mediada por SRP.
- Este dominio es específicamente responsable de conferir la actividad de detención de la elongación en el SRP.
Más Videos Relacionados
11:57Studying Protein Function and the Role of Altered Protein Expression by Antibody Interference and Three-dimensional Reconstructions
Published on: April 21, 2016
05:48Removal of an Internal Translational Start Site from mRNA While Retaining Expression of the Full-Length Protein
Published on: March 16, 2022
Videos de Conceptos Relacionados
01:34Directing Proteins to the Rough Endoplasmic Reticulum
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...
01:20Cotranslational Protein Translocation
Translocation of proteins across membranes is an ancient process that occurs even in bacteria and archaebacteria. In fact, the components of the translocation machinery are still conserved between prokaryotes and eukaryotes.
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
01:26Insertion of Single-pass Transmembrane Proteins in the RER
Integral membrane proteins are proteins adhered to the lipid bilayer of a cell organelle or membrane. They can be of two types: transmembrane integral proteins that span the lipid bilayer and monotopic proteins that are attached to either side of the membrane but do not pass through it.
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
01:27Post-translational Translocation of Proteins to the RER
A sizable fraction of proteins destined for ER are first synthesized in the cell cytosol and then transported across the ER membrane–a process called post-translational translocation. Similar to cotranslationally translocated proteins, these proteins also use the Sec translocon complex to enter the ER lumen.
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
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...
01:28Protein Translocation Machinery on the ER Membrane
The translocon complex situated on the ER membrane is the main gateway for the protein secretory pathway. It facilitates the transport of nascent peptides into the ER lumen and their insertion into the ER membrane.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the translocon complex.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the translocon complex.