Ca2+ entry through plasma membrane IP3 receptors.

Dellis, Olivier; Dedos, Skarlatos G; Tovey, Stephen C; Dubel, Stefan J; Taylor, Colin W

Dellis, Olivier; Dedos, Skarlatos G; Tovey, Stephen C; Dubel, Stefan J; Taylor, Colin W.

Afiliación

Dellis O; Department of Pharmacology, Tennis Court Road, Cambridge, CB2 1PD, UK.

Science ; 313(5784): 229-33, 2006 Jul 14.

Article en En | MEDLINE | ID: mdl-16840702

RESUMEN

Inositol 1,4,5-trisphosphate receptors (IP3Rs) release calcium ions, Ca2+, from intracellular stores, but their roles in mediating Ca2+ entry are unclear. IP3 stimulated opening of very few (1.9 +/- 0.2 per cell) Ca2+-permeable channels in whole-cell patch-clamp recording of DT40 chicken or mouse B cells. Activation of the B cell receptor (BCR) in perforated-patch recordings evoked the same response. IP3 failed to stimulate intracellular or plasma membrane (PM) channels in cells lacking IP3R. Expression of IP3R restored both responses. Mutations within the pore affected the conductances of IP3-activated PM and intracellular channels similarly. An impermeant pore mutant abolished BCR-evoked Ca2+ signals, and PM IP3Rs were undetectable. After introduction of an alpha-bungarotoxin binding site near the pore, PM IP3Rs were modulated by extracellular alpha-bungarotoxin. IP(3)Rs are unusual among endoplasmic reticulum proteins in being also functionally expressed at the PM, where very few IP3Rs contribute substantially to the Ca2+ entry evoked by the BCR.

Asunto(s)

Canales de Calcio/metabolismo; Señalización del Calcio; Calcio/metabolismo; Membrana Celular/metabolismo; Activación del Canal Iónico; Receptores Citoplasmáticos y Nucleares/metabolismo; Animales; Linfocitos B/metabolismo; Bungarotoxinas/metabolismo; Bungarotoxinas/farmacología; Canales de Calcio/genética; Células Cultivadas; Pollos; Conductividad Eléctrica; Retículo Endoplásmico/metabolismo; Inositol 1,4,5-Trifosfato/metabolismo; Receptores de Inositol 1,4,5-Trifosfato; Ratones; Membrana Nuclear/metabolismo; Técnicas de Placa-Clamp; Mutación Puntual; Ratas; Receptores de Antígenos de Linfocitos B/metabolismo; Receptores Citoplasmáticos y Nucleares/antagonistas & inhibidores; Receptores Citoplasmáticos y Nucleares/genética; Transfección

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Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Canales de Calcio / Activación del Canal Iónico / Membrana Celular / Calcio / Receptores Citoplasmáticos y Nucleares / Señalización del Calcio Límite: Animals Idioma: En Revista: Science Año: 2006 Tipo del documento: Article Pais de publicación: Estados Unidos

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