Allosteric modulation of metabotropic glutamate receptors by chloride ions.
FASEB J
; 29(10): 4174-88, 2015 Oct.
Article
en En
| MEDLINE
| ID: mdl-26116702
ABSTRACT
Metabotropic glutamate receptors (mGluRs) play key roles in the modulation of many synapses. Chloride (Cl(-)) is known to directly bind and regulate the function of different actors of neuronal activity, and several studies have pointed to the possible modulation of mGluRs by Cl(-). Herein, we demonstrate that Cl(-) behaves as a positive allosteric modulator of mGluRs. For example, whereas glutamate potency was 3.08 ± 0.33 µM on metabotropic glutamate (mGlu) 4 receptors in high-Cl(-) buffer, signaling activity was almost abolished in low Cl(-) in cell-based assays. Cl(-) potency was 78.6 ± 3.5 mM. Cl(-) possesses a high positive cooperativity with glutamate (Hill slope ≈6 on mGlu4), meaning that small variations in [Cl(-)] lead to large variations in glutamate action. Using molecular modeling and mutagenesis, we have identified 2 well-conserved Cl(-) binding pockets in the extracellular domain of mGluRs. Moreover, modeling of activity-dependent Cl(-) variations at GABAergic synapses suggests that these variations may be compatible with a dynamic modulation of the most sensitive mGluRs present in these synapses. Taken together, these data reveal a necessary role of Cl(-) for the glutamate activation of many mGluRs. Exploiting Cl(-) binding pockets may yield to the development of innovative regulators of mGluR activity.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Cloruros
/
Receptores de Glutamato Metabotrópico
/
Espacio Extracelular
Límite:
Animals
/
Humans
Idioma:
En
Revista:
FASEB J
Asunto de la revista:
BIOLOGIA
/
FISIOLOGIA
Año:
2015
Tipo del documento:
Article