Video Experimental Relacionado
Updated: Jul 10, 2026
11:55
Membrane Transport Processes Analyzed by a Highly Parallel Nanopore Chip System at Single Protein Resolution
Published on: August 16, 2016
El túnel de salida ribosomal funciona como una puerta de discriminación
Hitoshi Nakatogawa1, Koreaki Ito
1Institute for Virus Research and CREST, Japan Science and Technology Corporation, Kyoto University, Japan.
Cell
|March 15, 2002
Resumen
La traducción de SecM se detiene debido a un motivo específico de arresto ribosómico. Las mutaciones supresoras en los componentes ribosómicos sugieren que el túnel de salida actúa como una puerta para los productos de proteínas nacientes.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Síntesis de proteínas Síntesis de proteínas
- Función del ribosoma Función del ribosoma
Sus antecedentes:
- SecM es una proteína cuya traducción está regulada por el mecanismo de exportación de proteínas.
- Las cadenas de proteínas nacientes que emergen del ribosoma pueden interactuar con el túnel de salida ribosomal.
- El mecanismo preciso de la detención de la traducción y su regulación no se entiende completamente.
Objetivo del estudio:
- Para investigar el mecanismo de SecM traducción de detención.
- Para identificar los componentes ribosómicos involucrados en la regulación de la traducción de SecM.
- Para aclarar el papel del túnel de salida ribosomal en la discriminación de productos de proteínas nacientes.
Principales métodos:
- Mutagénesis dirigida al sitio para introducir mutaciones en SecM y componentes ribosómicos.
- Pruebas de traducción in vitro para monitorear la síntesis de proteínas y la detención del alargamiento.
- Análisis de las mutaciones supresoras en el ARN ribosomal 23S (ARNr) y la proteína ribosomal L22.
Principales resultados:
- Un motivo de secuencia específico (FXXXXWIXXXXGIRAGP) en SecM, que contiene un residuo de prolina, induce la detención de la elongación dentro del ribosoma.
- Se identificaron mutaciones en el ARNr 23S y la proteína ribosómica L22 que suprimen esta detención de la elongación.
- Estas mutaciones supresoras se relacionan con los residuos que recubren la parte más estrecha del túnel de salida ribosomal.
Conclusiones:
- El motivo de secuencia identificado actúa como un punto de detención específico durante la traducción.
- La estrecha constricción del túnel de salida ribosomal juega un papel crítico en la detección y respuesta a las cadenas de polipéptidos nacientes.
- Esta región del ribosoma funciona como una puerta de discriminación, controlando el paso de las proteínas en función de su secuencia y estructura.
Videos de Conceptos Relacionados
01:55Secondary Active Transport
One example of how cells use the energy contained in electrochemical gradients is demonstrated by glucose transport into cells. The ion vital to this process is sodium (Na+), which is typically present in higher concentrations extracellularly than in the cytosol. Such a concentration difference is due, in part, to the action of an enzyme “pump” embedded in the cellular membrane that actively expels Na+ from a cell. Importantly, as this pump contributes to the high concentration of...
01:30Membrane Proteins
Plasma membranes have integral transmembrane proteins involved in facilitated transport. These proteins are collectively referred to as transport proteins, and they function as either channels for the material or as carriers themselves. Channel proteins have hydrophilic domains exposed to the intracellular and extracellular fluids and a hydrophilic channel through their core that provides a hydrated opening for solutes to pass through the membrane layers. Passage through the channel allows...
01:32Secondary Active Transport
One example of how cells use the energy contained in electrochemical gradients is demonstrated by glucose transport into cells. The ion vital to this process is sodium (Na+), which is typically present in higher concentrations extracellularly than in the cytosol. Such a concentration difference is due, in part, to the action of an enzyme "pump" embedded in the cellular membrane that actively expels Na+ from a cell. Importantly, as this pump contributes to the high concentration of...
01:27Glucose Transporters
Glucose transporters facilitate the transport of glucose across the cell membrane. In addition to glucose, some glucose transporters can also aid the movement of other hexoses such as fructose, mannose, and galactose.
Facilitated diffusion-glucose transporters (GLUTs) are encoded by the solute-linked carrier (SLC) family 2, subfamily A gene family, or SLC2A. The 14 GLUT protein members are distributed into three classes:
Facilitated diffusion-glucose transporters (GLUTs) are encoded by the solute-linked carrier (SLC) family 2, subfamily A gene family, or SLC2A. The 14 GLUT protein members are distributed into three classes:
01:26Glucose Absorption Into the Small Intestine
Complex carbohydrates consumed cannot be absorbed into the small intestine in their original form. First, they must be hydrolyzed to a monosaccharide form such as glucose or galactose. These monosaccharides are then transported across the intestinal membrane and into the blood via transcellular transport. The intestinal epithelial cells allow the movement of these monosaccharides with a defined 'entry' through membrane transporter proteins present on their apical membrane and 'exit' via the...
01:32Secondary Active Transport
One example of how cells use the energy contained in electrochemical gradients is demonstrated by glucose transport into cells. The ion vital to this process is sodium (Na+), which is typically present in higher concentrations extracellularly than in the cytosol. Such a concentration difference is due, in part, to the action of an enzyme "pump" embedded in the cellular membrane that actively expels Na+ from a cell. Importantly, as this pump contributes to the high concentration of...