Identification of the differentiation-associated Na+/PI transporter as a novel vesicular glutamate transporter expressed in a distinct set of glutamatergic synapses.
J Neurosci
; 22(1): 142-55, 2002 Jan 01.
Article
em En
| MEDLINE
| ID: mdl-11756497
ABSTRACT
Glutamate transport into synaptic vesicles is a prerequisite for its regulated neurosecretion. Here we functionally identify a second isoform of the vesicular glutamate transporter (VGLUT2) that was previously identified as a plasma membrane Na+-dependent inorganic phosphate transporter (differentiation-associated Na+/P(I) transporter). Studies using intracellular vesicles from transiently transfected PC12 cells indicate that uptake by VGLUT2 is highly selective for glutamate, is H+ dependent, and requires Cl- ion. Both the vesicular membrane potential (Deltapsi) and the proton gradient (DeltapH) are important driving forces for vesicular glutamate accumulation under physiological Cl- concentrations. Using an antibody specific for VGLUT2, we also find that this protein is enriched on synaptic vesicles and selective for a distinct class of glutamatergic nerve terminals. The pathway-specific, complementary expression of two different vesicular glutamate transporters suggests functional diversity in the regulation of vesicular release at excitatory synapses. Together, the two isoforms may account for the uptake of glutamate by synaptic vesicles from all central glutamatergic neurons.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Membrana Transportadoras
/
Proteínas de Transporte
/
Proteínas de Transporte Vesicular
Tipo de estudo:
Diagnostic_studies
/
Risk_factors_studies
Idioma:
En
Ano de publicação:
2002
Tipo de documento:
Article