Calmodulin as a direct detector of Ca2+ signals.
Nat Neurosci
; 14(3): 301-4, 2011 Mar.
Article
en En
| MEDLINE
| ID: mdl-21258328
ABSTRACT
Many forms of signal transduction occur when Ca(2+) enters the cytoplasm of a cell. It has been generally thought that there is a fast buffer that rapidly reduces the free Ca(2+) level and that it is this buffered level of Ca(2+) that triggers downstream biochemical processes, notably the activation of calmodulin (CaM) and the resulting activation of CaM-dependent enzymes. Given the importance of these transduction processes, it is crucial to understand exactly how Ca(2+) activates CaM. We have determined the rate at which Ca(2+) binds to CaM and found that Ca(2+) binds more rapidly to CaM than to other Ca(2+)-binding proteins. This property of CaM and its high concentration support a new view of signal transduction CaM directly intercepts incoming Ca(2+) and sets the free Ca(2+) level (that is, it strongly contributes to fast Ca(2+) buffering) rather than responding to the lower Ca(2+) level set by other buffers. This property is crucial for making CaM an efficient transducer. Our results also suggest that other Ca(2+) binding proteins have a previously undescribed role in regulating the lifetime of Ca(2+) bound to CaM and thereby setting the gain of signal transduction.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Calmodulina
/
Calcio
/
Señalización del Calcio
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Nat Neurosci
Asunto de la revista:
NEUROLOGIA
Año:
2011
Tipo del documento:
Article
País de afiliación:
Estados Unidos