Video Experimental Relacionado

Updated: Jan 18, 2026

A Kinetic Fluorescence-based Ca2+ Mobilization Assay to Identify G Protein-coupled Receptor Agonists, Antagonists, and Allosteric Modulators

A Kinetic Fluorescence-based Ca2+ Mobilization Assay to Identify G Protein-coupled Receptor Agonists, Antagonists, and Allosteric Modulators

Published on: February 20, 2018

Clase B1 activación de GPCR por un agonista intracelular

Kazuhiro Kobayashi¹, Kouki Kawakami², Tsukasa Kusakizako¹

¹Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.

|June 7, 2023

Resumen

Los investigadores descubrieron una nueva bolsa de unión intracelular en los receptores acoplados a proteínas G (GPCR). Este hallazgo revela cómo los agonistas sesgados activan selectivamente las vías de señalización, ofreciendo nuevas vías de desarrollo de fármacos.

Área de la Ciencia:

Biología estructural
Farmacología
La bioquímica

Sus antecedentes:

Los receptores acoplados a proteínas G (GPCR) típicamente se unen a los ligandos en las bolsas ortostéricas, desencadenando cambios conformacionales y activando las proteínas G y las β-arrestinas.
Los efectos adversos de la señalización requieren la comprensión de la activación selectiva del transductor.
Los agonistas sesgados intracelulares, que se unen dentro de la cavidad intracelular del receptor, son de interés reciente para la señalización específica de la vía.

Objetivo del estudio:

Para aclarar las bases estructurales del agonismo intracelular sesgado.
Proporcionar evidencia de la unión del agonista dentro de la cavidad intracelular de los GPCR.
Comprender el mecanismo de la activación selectiva de la proteína G frente a la β-arrestina.

Principales métodos:

Se utilizó la microscopía electrónica criogénica (cryo-EM) para determinar la estructura de un complejo.
El complejo consistía en el receptor de la hormona paratiroidea humana tipo 1 (PTH1R), Gs y el agonista PCO371.
El análisis estructural se centró en el modo de unión de PCO371 y su efecto en la conformación del receptor.

Principales resultados:

La estructura reveló que el agonista PCO371 se une dentro de una bolsa intracelular de PTH1R, interactuando directamente con Gs.
Esta unión induce una conformación activa sin propagación de la señal alosterica extracelular, estabilizando la hélice transmembrana 6.
PCO371 activa 7 de los 15 GPCR de clase B1 al unirse a una bolsa intracelular conservada.

Conclusiones:

Se ha identificado una nueva y conservada bolsa de unión de agonistas intracelulares en los GPCR.
El estudio proporciona evidencia estructural para el agonismo intracelular sesgado dirigido a la interfaz receptor-transductor.
Este mecanismo facilita preferentemente la unión a la proteína G sobre la unión a la β-arrestina, ofreciendo información para el desarrollo de fármacos selectivos.

Más Videos Relacionados

Characterization of G Protein-coupled Receptors by a Fluorescence-based Calcium Mobilization Assay

Characterization of G Protein-coupled Receptors by a Fluorescence-based Calcium Mobilization Assay

Published on: July 28, 2014

Monitoring GPCR-β-arrestin1/2 Interactions in Real Time Living Systems to Accelerate Drug Discovery

Monitoring GPCR-β-arrestin1/2 Interactions in Real Time Living Systems to Accelerate Drug Discovery

Published on: June 28, 2019

Videos de Conceptos Relacionados

GPCRs Regulate Adenylyl Cylase Activity

GPCRs Regulate Adenylyl Cylase Activity

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...

Activation and Inactivation of G Proteins

Activation and Inactivation of G Proteins

Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high...

G Protein-coupled Receptors

G Protein-coupled Receptors

G Protein-Coupled Receptors or GPCRs are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to sensory stimuli such as light, odors, hormones, cytokines, or neurotransmitters.
GPCRs are also called heptahelical, 7TM, or serpentine receptors, and consist of seven (H1-H7) transmembrane alpha-helices that span the bilayer to form a cylindrical core. The transmembrane helices are connected by three extracellular loops and three...

G-Protein Gated Ion Channels

G-Protein Gated Ion Channels

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...

G-protein Coupled Receptors

G-protein Coupled Receptors

G-protein coupled receptors are ligand binding receptors that indirectly affect changes in the cell. The actual receptor is a single polypeptide that transverses the cell membrane seven times creating intracellular and extracellular loops. The extracellular loops create a ligand specific pocket which binds to neurotransmitters or hormones. The intracellular loops holds onto the G-protein.

Transducer Mechanism: G Protein–Coupled Receptors

Transducer Mechanism: G Protein–Coupled Receptors

G Protein–Coupled Receptors (GPCRs) are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to various stimuli. GPCRs regulate critical physiological pathways and are excellent drug targets for treating diseases such as diabetes, cancer, obesity, depression, or Alzheimer's. Nearly 35% of approved drugs implement their therapeutic effects by selectively interacting with specific GPCRs.
GPCRs are also called heptahelical,...