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Una pantalla de siRNA para la activación de NFAT identifica las septinas como coordinadoras de la entrada de Ca2+

Sonia Sharma¹, Ariel Quintana, Gregory M Findlay

¹La Jolla Institute for Allergy and Immunology, La Jolla, California 92037, USA.

|June 25, 2013

Resumen

Las proteínas de la septina organizan la señalización del calcio celular mediante la regulación de la vía STIM1-ORAI1. Estos hallazgos revelan septinas.

Área de la Ciencia:

Biología celular Biología celular.
La señalización molecular.
La bioquímica es la bioquímica.

Sus antecedentes:

La vía STIM1-ORAI1 es crucial para la señalización celular de calcio (Ca2+), controlando la entrada de Ca2+ en las células.
La proteína STIM1 detecta el agotamiento de las reservas de Ca2+ y recluta canales ORAI1 a la membrana plasmática.
La desregulación de la señalización de Ca2+ está implicada en varias enfermedades.

Objetivo del estudio:

Para identificar nuevos reguladores de la vía STIM1-ORAI1.
Para investigar el papel de las proteínas de la septina filamentosa en la entrada de calcio operado en el almacén.
Aclarar el mecanismo por el cual las septinas influyen en la formación del complejo STIM1-ORAI1.

Principales métodos:

Pantalla de interferencia de ARN de todo el genoma (RNAi) en las células HeLa.
Imágenes de células vivas para observar la dinámica de STIM1 y ORAI1.
Análisis de la localización del fosfatidilinositol-4,5-bisfosfato (PtdIns(4,5) P2.
Técnicas de microscopía para estudiar las interacciones estructurales proteína-célula.

Principales resultados:

Se identificaron proteínas de septina filamentosa como reguladores críticos de la entrada de calcio operado por el almacén.
Los filamentos de septina y los PtdIns ((4,5) P2 se reorganizan en las uniones entre el retículo endoplasmático y la membrana plasmática durante el agrupamiento STIM1-ORAI1.
El reordenamiento de la septina facilita la orientación de STIM1 y el reclutamiento estable de ORAI1, mejorando la comunicación STIM1-ORAI1.
Las septinas organizan dominios localizados de la membrana plasmática esenciales para la señalización STIM1-ORAI1.

Conclusiones:

Las septinas juegan un papel vital en la organización de los dominios de membrana localizados requeridos para una eficiente señalización de calcio STIM1-ORAI1.
Las septinas pueden actuar como andamios para organizar los microdominios de señalización en varios procesos celulares.
Este estudio amplía las funciones conocidas de las septinas para incluir la regulación de la entrada de calcio operado en el almacén.

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