Extramitochondrial Ca2+ in the nanomolar range regulates glutamate-dependent oxidative phosphorylation on demand.
PLoS One
; 4(12): e8181, 2009 Dec 09.
Article
en En
| MEDLINE
| ID: mdl-20011041
ABSTRACT
We present unexpected and novel results revealing that glutamate-dependent oxidative phosphorylation (OXPHOS) of brain mitochondria is exclusively and efficiently activated by extramitochondrial Ca(2+) in physiological concentration ranges (S(0.5) = 360 nM Ca(2+)). This regulation was not affected by RR, an inhibitor of the mitochondrial Ca(2+) uniporter. Active respiration is regulated by glutamate supply to mitochondria via aralar, a mitochondrial glutamate/aspartate carrier with regulatory Ca(2+)-binding sites in the mitochondrial intermembrane space providing full access to cytosolic Ca(2+). At micromolar concentrations, Ca(2+) can also enter the intramitochondrial matrix and activate specific dehydrogenases. However, the latter mechanism is less efficient than extramitochondrial Ca(2+) regulation of respiration/OXPHOS via aralar. These results imply a new mode of glutamate-dependent OXPHOS regulation as a demand-driven regulation of mitochondrial function. This regulation involves the mitochondrial glutamate/aspartate carrier aralar which controls mitochondrial substrate supply according to the level of extramitochondrial Ca(2+).
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Fosforilación Oxidativa
/
Calcio
/
Ácido Glutámico
/
Mitocondrias
Límite:
Animals
Idioma:
En
Revista:
PLoS One
Asunto de la revista:
CIENCIA
/
MEDICINA
Año:
2009
Tipo del documento:
Article
País de afiliación:
Alemania