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La expresión α2δ establece la abundancia del canal de calcio presináptico y la probabilidad de liberación
Michael B Hoppa1, Beatrice Lana, Wojciech Margas
1Department of Biochemistry, Weill Cornell Medical College, New York, New York 10023, USA.
Nature
|June 9, 2012
Resumen
El estudio revela que las subunidades alfa2delta (α2δ) regulan los niveles y la función del canal de calcio sináptico controlado por voltaje (VGCC). Estas subunidades aumentan la probabilidad de liberación de neurotransmisores al permitir un flujo eficiente de calcio (Ca2+) y la exocitosis en la sinapsis.
Área de la Ciencia:
- La neurociencia es la neurociencia.
- Biología Molecular Biología Molecular
- La transmisión sináptica es la transmisión sináptica.
Sus antecedentes:
- La liberación de neurotransmisores sinápticos depende de la afluencia de calcio (Ca2+) a través de los canales de calcio controlados por voltaje (VGCC) en la zona activa.
- Los mecanismos que controlan la abundancia y la función de VGCC en las sinapsis no se comprenden completamente.
- Las subunidades alfa2delta (α2δ) están asociadas con los VGCC y son objetivos de los gabapentinoides, utilizados para el dolor neuropático.
Objetivo del estudio:
- Investigar el papel de las subunidades α2δ en la regulación de la abundancia y función sináptica de VGCC.
- Para dilucidar los mecanismos moleculares por los cuales las subunidades α2δ modulan la liberación del neurotransmisor presináptico.
Principales métodos:
- Sobreexpresión de la subunidad de VGCC α1 (A) formadora de poros en ratas para evaluar su efecto en los niveles sinápticos de VGCC.
- Análisis de la función de la subunidad α2δ en la modulación de la abundancia de VGCC y la probabilidad de liberación.
- Investigación del papel del motivo del sitio de adhesión dependiente de iones metálicos (MIDAS) dentro de las subunidades α2δ.
Principales resultados:
- La sobreexpresión de la subunidad α1 (A) por sí sola no alteró la abundancia o función sináptica de VGCC, lo que sugiere una regulación dependiente del tráfico.
- Se encontró que las subunidades α2δ establecen la abundancia de VGCC sináptico, actuando como chaperones.
- Las subunidades α2δ con un motivo MIDAS intacto aumentaron significativamente la probabilidad de liberación (80%) y protegieron la exocitosis de la quelación de Ca2+, lo que indica un papel en la configuración de los VGCC para una exocitosis eficiente.
Conclusiones:
- Las subunidades α2δ desempeñan un doble papel en la función sináptica: regulan el tráfico de VGCC a la sinapsis y configuran los VGCC para mejorar la exocitosis impulsada por Ca2+.
- El motivo MIDAS en las subunidades α2δ es crucial para modular la probabilidad de liberación y la sensibilidad al Ca2+.
- Estos hallazgos resaltan la importancia clínica de las subunidades α2δ en la transmisión sináptica y la modulación del dolor.
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