Video Experimental Relacionado
Updated: May 20, 2025
08:27
Single Synapse Indicators of Glutamate Release and Uptake in Acute Brain Slices from Normal and Huntington Mice
Published on: March 11, 2020
6.1K
Glutamato de las iGluR del subtipo AMPA a temperaturas fisiológicas
Anish Kumar Mondal1,2, Elisa Carrillo3, Vasanthi Jayaraman4,5
1Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Nature
|March 27, 2025
Resumen
Los investigadores descubrieron el mecanismo de entrada de glutamato en los receptores ionotrópicos de glutamato (iGluR), revelando cómo se abren y cierran estos canales críticos. Este descubrimiento proporciona información sobre la neurotransmisión excitatoria y los posibles objetivos terapéuticos.
Área de la Ciencia:
- La neurociencia
- Biología estructural
- La bioquímica
Sus antecedentes:
- Los receptores ionotrópicos del glutamato (iGluR) son esenciales para la neurotransmisión excitatoria.
- Los mecanismos estructurales precisos de la entrada de glutamato en iGluR siguen siendo en gran medida desconocidos.
- La comprensión de la entrada de iGluR es crucial para comprender la señalización neuronal y desarrollar terapias.
Objetivo del estudio:
- Para aclarar la mecánica estructural de la entrada de glutamato en los receptores de glutamato ionotrópicos de longitud completa.
- Identificar el mecanismo de retención conservado en todos los subtipos de iGluR.
- Investigar la influencia de las temperaturas fisiológicas en la activación y el gating de AMPAR.
Principales métodos:
- Se utilizó la microscopía electrónica criogénica (cryo-EM) para capturar instantáneas estructurales de los AMPAR.
- Preparado y analizado AMPARs a temperaturas fisiológicas para imitar las condiciones celulares.
- Investigó los cambios conformacionales asociados con la unión al glutamato y la activación/desensibilización del canal.
Principales resultados:
- Identificó un mecanismo de enlace conservado que involucra a todas las hélices de los canales iónicos que se alejan del eje del poro al unirse al glutamato.
- Se ha demostrado que la activación de AMPAR se incrementa a temperaturas fisiológicas.
- La desensibilización implica el desacoplamiento de pares de dímeros, lo que lleva al cierre del canal a través de la restauración de bisagras y el plegado de puertas.
Conclusiones:
- Se ha definido el mecanismo molecular por el cual el glutamato se conecta a los receptores ionotrópicos del glutamato.
- Estableció una base estructural para comprender la función y la disfunción de iGluR.
- Destacó el papel significativo de las temperaturas fisiológicas en la modulación de la actividad de iGluR, con implicaciones para el diseño de fármacos.
Videos de Conceptos Relacionados
01:30Ligand-Gated Ion Channel Receptor: Gating Mechanism
2.1K
Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...
2.1K
01:19Ligand-gated Ion Channels
12.1K
Ligand-gated ion channels are transmembrane proteins with a channel for ions to pass through and a binding site for a ligand. The channel opens only when a ligand attaches to the binding site.
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that...
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that...
12.1K
01:21G-Protein Gated Ion Channels
4.5K
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory...
Sensory...
4.5K
01:12Mechanically-gated Ion Channels
6.1K
Mechanically-gated ion channels are proteins found in eukaryotic and prokaryotic cell membranes that open in response to mechanical stress. Tension, compression, swelling, and shear stress can alter the conformation of the protein, opening a transmembrane channel that allows the passage of ions for signal transmission. In eukaryotes, mechanically-gated channels are distributed in several regions like the neurons, lungs, skin, bladder, and heart, where they play critical roles in numerous...
6.1K
01:09GPCRs Regulate Adenylyl Cylase Activity
5.1K
Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of...
5.1K