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Una toxina bivalente de tarántula activa el receptor de capsaicina, TRPV1, al dirigirse al dominio de los poros
Christopher J Bohlen1, Avi Priel, Sharleen Zhou
1Department of Physiology, University of California, San Francisco, San Francisco, CA 94143-2140, USA.
Cell
|June 1, 2010
Resumen
Una nueva toxina de tarántula, el péptido de "doble nudo", activa irreversiblemente el canal TRPV1. Su estructura bivalente única pone de relieve el papel de los cambios de conformación de los poros externos en la activación del canal TRP.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Molecular Biología Molecular
- La neurociencia es la neurociencia.
Sus antecedentes:
- Las toxinas son herramientas cruciales para estudiar la estructura y la función de los canales iónicos.
- El canal del receptor transitorio potencial del vanilloide 1 (TRPV1) es activado por la capsaicina y el calor.
- Comprender los mecanismos de entrada del TRPV1 es vital para la investigación del dolor.
Objetivo del estudio:
- Para caracterizar una nueva toxina peptídica de la tarántula tigre de la Tierra.
- Para investigar el mecanismo de acción de la toxina en el canal TRPV1.
- Para aclarar la base estructural de la interacción de la toxina-canal.
Principales métodos:
- Aislamiento y caracterización de un péptido de veneno de tarántula.
- Grabaciones electrofisiológicas para evaluar la actividad del canal TRPV1.
- Análisis estructural de los dominios repetidos en tándem de la toxina.
Principales resultados:
- Una nueva toxina peptídica activa selectivamente e irreversiblemente el TRPV1.
- La toxina exhibe bivalencia parecida a un anticuerpo debido a su estructura de repetición en tándem.
- La toxina se une a los residuos en la región externa de los poros, atrapando a TRPV1 en estado abierto.
Conclusiones:
- La toxina de la tarántula tigre de la tierra proporciona una nueva herramienta para el estudio de TRPV1.1.
- La bivalencia de la toxina es clave para su interacción de alta avidez con el TRPV1.1.
- Los cambios de conformación en el poro externo son críticos para la activación del canal TRP.
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