The lumenal ionic content of an organelle is determined by its complement of channels and transporters. These proteins reach their resident organelles by adaptor-dependent mechanisms. This concept is illustrated in AP-3 deficiencies, in which synaptic vesicle zinc is depleted because the synaptic-vesicle-specific zinc transporter 3 does not reach synaptic vesicles. However, whether zinc transpo...

Glutamate uptake by transporters expressed in astrocytes combines with synaptic structure to regulate the time that synaptically released glutamate remains in the extracellular space and, consequently, the duration and location of postsynaptic receptor activation. Both factors change greatly in the rodent hippocampus during the second postnatal week when most synapses become established and beg...

The glutamate/aspartate transporter GLAST-1 is expressed in bone in vivo and also exists as a splice variant (GLAST-1a) in which exon 3 is excluded. Since GLAST-1 expression is regulated in bone in response to osteogenic mechanical stimuli in vivo and binding of glutamate to receptors on osteoblasts increases osteoblast number and activity in vitro, control of extracellular glutamate concentrat...

Glutamate contributes to the acid tolerance response (ATR) of many Gram-negative and Gram-positive bacteria, but its role in the ATR of the oral bacterium Streptococcus mutans is unknown. This study describes the discovery and characterization of a glutamate transporter operon designated glnQHMP (Smu.1519 to Smu.1522) and investigates its potential role in acid tolerance. Deletion of glnQHMP re...

Glutamate transporters are involved in the maintenance of synaptic glutamate concentrations. Because of its potential neurotoxicity, clearance of glutamate from the synaptic cleft may be critical for neuronal survival. Inhibition of glutamate uptake from the synapse has been implicated in several neurodegenerative disorders. In particular, glutamate uptake is inhibited in Alzheimer's disease (A...

Although it has long been believed that glial cells play a major role in transmitter uptake at synapses in the CNS, the relative contribution of glial and neuronal cells to reuptake of synaptically released glutamate has been unclear. Recent identification of the diverse glutamate transporter subtypes provides an opportunity to examine this issue. To monitor glutamate transporter activity, we o...

In the adult rat hippocampus, granule cell mossy fibers (MFs) form excitatory glutamatergic synapses with CA3 principal cells and local inhibitory interneurons. However, evidence has been provided that, in young animals and after seizures, the same fibers can release in addition to glutamate GABA. Here we show that, during the first postnatal week, stimulation of granule cells in the dentate gy...

T cell infiltration into the CNS is a significant underlying pathogenesis in autoimmune inflammatory demyelinating diseases. Several lines of evidence suggest that glutamate dysregulation in the CNS is an important consequence of immune cell infiltration in neuroinflammatory demyelinating diseases; yet, the causal link between inflammation and glutamate dysregulation is not well understood. A m...