Determinación de la interacción entre el dominio intracelular de receptor de glicina α3 y la proteína del complejo de exocitosis SEC8.
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Date
2024
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Publisher
Universidad de Concepción
Abstract
El receptor de glicina (GlyR), es un canal iónico pentamerico activado por ligando (pLGIC), crucial para regular la excitabilidad neuronal, y está implicado en afecciones como la hiperekplexia, el dolor crónico y la epilepsia. GlyR, que comprende cuatro subunidades alfa y una subunidad beta, puede existir en configuraciones homopentamérica (solo α) o heteropentamérica (α y β en una proporción de 4:1). Aunque los moduladores alostéricos históricamente se dirigieron a los dominios extracelular (ECD) y transmembrana (TMD), estudios recientes sugieren una modulación a través del dominio intracelular (ICD) que históricamente estuvo relacionado con la agrupación sináptica. Se descubrió que las proteínas intracelulares Gbeta-gamma mejoran su función. En particular, se identificó una nueva interacción del ICD GlyR α3 con la proteína SEC8, que influye en el transporte y tráfico axonal sin claridad sobre el impacto funcional. Este estudio investiga el efecto funcional de la interacción GlyR-SEC8 utilizando métodos bioquímicos, inmunohistoquímicos y electrofisiológicos. Nuestros resultados revelan un desplazamiento a la izquierda en la curva dosis-respuesta, lo que indica una mayor tasa de desensibilización sin alterar la expresión en la membrana o las corrientes máximas. Estos hallazgos abren nuevas vías para explorar la regulación de GlyR por componentes intracelulares.
The glycine receptor (GlyR), is a pentameric ligand-gated ion channel (pLGIC), crucial for regulating neuronal excitability, is implicated in conditions such as hyperekplexia, chronic pain, and epilepsy. GlyR, which comprises four alpha subunits and one beta subunit, can exist in homopentameric (α only) or heteropentameric (α and β in a 4:1 ratio) configurations. Although allosteric modulators historically targeted the extracellular (ECD) and transmembrane domains (TMD), recent studies suggest modulation through the intracellular domain (ICD) that was historically related to synaptic clustering. It was discovered that intracellular Gbeta-gamma proteins enhance its function. In particular, a novel interaction of the GlyR α3 ICD with the SEC8 protein was identified, which influences axonal transport and trafficking without clarity on the functional impact. This study investigates the functional effect of GlyR-SEC8 interaction using biochemical, immunohistochemical and electrophysiological methods. Our results reveal a left shift in the dose-response curve, indicating an increased rate of desensitization without altering membrane expression or peak currents. These findings open new avenues to explore the regulation of GlyR by intracellular components.
The glycine receptor (GlyR), is a pentameric ligand-gated ion channel (pLGIC), crucial for regulating neuronal excitability, is implicated in conditions such as hyperekplexia, chronic pain, and epilepsy. GlyR, which comprises four alpha subunits and one beta subunit, can exist in homopentameric (α only) or heteropentameric (α and β in a 4:1 ratio) configurations. Although allosteric modulators historically targeted the extracellular (ECD) and transmembrane domains (TMD), recent studies suggest modulation through the intracellular domain (ICD) that was historically related to synaptic clustering. It was discovered that intracellular Gbeta-gamma proteins enhance its function. In particular, a novel interaction of the GlyR α3 ICD with the SEC8 protein was identified, which influences axonal transport and trafficking without clarity on the functional impact. This study investigates the functional effect of GlyR-SEC8 interaction using biochemical, immunohistochemical and electrophysiological methods. Our results reveal a left shift in the dose-response curve, indicating an increased rate of desensitization without altering membrane expression or peak currents. These findings open new avenues to explore the regulation of GlyR by intracellular components.
Description
Tesis presentada para optar al grado de Magíster en Neurobiología
Keywords
Canales iónicos, Glicina, Sitios alostéricos