Nuclear and cytosolic calcium are regulated independently.
Proc Natl Acad Sci U S A
; 100(5): 2975-80, 2003 Mar 04.
Article
en En
| MEDLINE
| ID: mdl-12606721
Nuclear calcium (Ca(2+)) regulates a number of important cellular processes, including gene transcription, growth, and apoptosis. However, it is unclear whether Ca(2+) signaling is regulated differently in the nucleus and cytosol. To investigate this possibility, we examined subcellular mechanisms of Ca(2+) release in the HepG2 liver cell line. The type II isoform of the inositol 1,4,5-trisphosphate (InsP(3)) receptor (InsP(3)R) was expressed to a similar extent in the endoplasmic reticulum and nucleus, whereas the type III InsP(3)R was concentrated in the endoplasmic reticulum, and the type I isoform was not expressed. Ca(2+) signals induced by low InsP(3) concentrations started earlier or were larger in the nucleus than in the cytosol, indicating higher sensitivity of nuclear Ca(2+) stores for InsP(3). Nuclear InsP(3)R channels were active at lower InsP(3) concentrations than InsP(3)R from cytosol. Enriched expression of type II InsP(3)R in the nucleus results in greater sensitivity of the nucleus to InsP(3), thus providing a mechanism for independent regulation of Ca(2+)-dependent processes in this cellular compartment.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Canales de Calcio
/
Núcleo Celular
/
Calcio
/
Receptores Citoplasmáticos y Nucleares
/
Citosol
Límite:
Humans
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Año:
2003
Tipo del documento:
Article
País de afiliación:
Brasil
Pais de publicación:
Estados Unidos