RT Journal Article
SR Electronic
T1 Identification of the Differentiation-Associated Na<sup>+</sup>/P<sub>I</sub> Transporter as a Novel Vesicular Glutamate Transporter Expressed in a Distinct Set of Glutamatergic Synapses
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 142
OP 155
DO 10.1523/JNEUROSCI.22-01-00142.2002
VO 22
IS 1
A1 Hélène Varoqui
A1 Martin K.-H. Schäfer
A1 Heming Zhu
A1 Eberhard Weihe
A1 Jeffrey D. Erickson
YR 2002
UL http://www.jneurosci.org/content/22/1/142.abstract
AB 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+/PItransporter). 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 (Δψ) and the proton gradient (ΔpH) 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.