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El andamiaje cinético mediado por una fosfolipasa C-beta y un complejo de señalización de Gq
Gary L Waldo1, Tiffany K Ricks, Stephanie N Hicks
1Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA.
Science (New York, N.Y.)
|October 23, 2010
Resumen
Las proteínas G activan la fosfolipasa C (PLC) para propagar señales, pero la PLC también desactiva las proteínas G. Este estudio revela un mecanismo de captura y liberación que agudiza las señales celulares.
Área de la Ciencia:
- Biología molecular La biología molecular.
- La señalización celular de las células.
- Biología estructural Biología estructural.
Sus antecedentes:
- Las señales de transmembrana convergen en la fosfolipasa C (PLC) para la propagación de la señal.
- Las proteínas heterotriméricas de unión de nucleótidos de guanina (proteínas G) activan las isoformas PLC-β.
Objetivo del estudio:
- Para dilucidar el mecanismo de la activación y desactivación del PLC-β mediada por la proteína G.
- Comprender cómo las PLC-βs son reguladas por las proteínas G para la terminación de la señal.
Principales métodos:
- Cristalografía de rayos X con una resolución de 2,7 angstroms.
- Análisis bioquímicos y mutagénesis dirigida al sitio.
- Estudios funcionales in vitro y in vivo.
Principales resultados:
- La estructura del PLC-β3 unido a Gα (q) revela un módulo efector conservado para la interacción de la proteína G.
- El sitio activo del PLC-β3 está ocluido por un tapón, probablemente retirado al anclarse la membrana.
- Un dominio distinto en PLC-β3 acelera la hidrólisis de GTP por Gα(q), promoviendo la disociación compleja.
Conclusiones:
- Un mecanismo dinámico de captura y liberación regula la señalización de la proteína G-PLC.
- Este mecanismo implica la unión de PLC-β3, la orientación y luego la aceleración de la actividad de la Gα(q) GTPasa.
- Los hallazgos sugieren cómo las señales espacio-temporales son agudizadas por diversos estímulos extracelulares.
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