Calcium dependent activation of skeletal muscle Ca2+ release channel (ryanodine receptor) by calmodulin.
Biochem Biophys Res Commun
; 213(3): 1082-90, 1995 Aug 24.
Article
en En
| MEDLINE
| ID: mdl-7544580
In this study terminal cisternae vesicles from rabbit skeletal muscle were fused into planar bilayers and the effect of calmodulin on single Ca2+ release channel currents was investigated. In the presence of 10(-7) and 10(-9) M free [Ca2+], nanomolar concentrations of calmodulin activated the channel by increasing the open probability of single-channel events in a dose dependent manner. The activatory effect of calmodulin was reversed by 10 microM ruthenium red. At 10(-5) M free [Ca2+], calmodulin (0.1-1 microM) inhibited channel activity. Calmodulin overlays were carried out using concentrations of Ca2+ similar to those used for the planar lipid bilayer assays. In the presence of 10(-7) M [Ca2+], calmodulin bound to the ryanodine receptor, to a region defined by residues 2937-3225 and 3546-3655. These results suggest that calmodulin may activate the Ca(2+)-release channel (ryanodine-receptor) by interacting with binding sites localized in the central portion of the RYR protomer.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Calmodulina
/
Canales de Calcio
/
Calcio
/
Músculo Esquelético
/
Proteínas Musculares
Límite:
Animals
Idioma:
En
Revista:
Biochem Biophys Res Commun
Año:
1995
Tipo del documento:
Article
País de afiliación:
Italia
Pais de publicación:
Estados Unidos