ATP‐Dependent Glutamate Uptake into Synaptic Vesicles from Cerebellar Mutant Mice

Fischer-Bovenkerk, Carolyn; Kish, Phillip E.; Ueda, Tetsufumi

doi:10.1111/j.1471-4159.1988.tb03068.x

Cited by 40 publications

(18 citation statements)

References 41 publications

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“…The plasma membrane and mitochondrial ATPase inhibitors, vanadate, oligomycin B, and ouabain, had no effect on glutamate uptake by VGLUT2 (Fig. 2C), which is in agreement with previous work (10,30).…”

Section: Molecularsupporting

confidence: 82%

“…It has been shown that glutamate can be accumulated into synaptic vesicles to concentrations of at least 60 mM through an ATP-dependent mechanism (32,33). The vesicular transport system, in contrast to the sodium-dependent plasma membrane transport system, is specific for glutamate, has a low affinity for glutamate, and is stimulated by physiologically relevant concentrations of chloride (12,13,29,30). These unique properties of the vesicular glutamate transporter are conserved in such diverse vertebrates as fish, reptiles, amphibians, and mammals (34).…”

Section: Discussionmentioning

confidence: 99%

“…Another feature of the vesicular glutamate transporter that segregates it from other neurotransmitter transporters is the marked stimulation seen in the presence of low, physiologically relevant concentrations of chloride (12,13,29,30). At low concentrations (1-5 mM), chloride stimulates transport, whereas higher concentrations (above 10 mM) inhibit transport.…”

Section: Molecularmentioning

confidence: 99%

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Molecular and Functional Analysis of a Novel Neuronal Vesicular Glutamate Transporter

Bai¹,

Collins

et al. 2001

Journal of Biological Chemistry

189

138

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Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system. Packaging and storage of glutamate into glutamatergic neuronal vesicles requires ATP-dependent vesicular glutamate uptake systems, which utilize the electrochemical proton gradient as a driving force. VGLUT1, the first identified vesicular glutamate transporter, is only expressed in a subset of glutamatergic neurons. We report here the molecular cloning and functional characterization of a novel glutamate transporter, VGLUT2, from mouse brain. VGLUT2 has all major functional characteristics of a synaptic vesicle glutamate transporter, including ATP dependence, chloride stimulation, substrate specificity, and substrate affinity. It has 75 and 79% amino acid identity with human and rat VGLUT1, respectively. However, expression patterns of VGLUT2 in brain are different from that of VGLUT1. In addition, VGLUT2 activity is dependent on both membrane potential and pH gradient of the electrochemical proton gradient, whereas VGLUT1 is primarily dependent on only membrane potential. The presence of VGLUT2 in brain regions lacking VGLUT1 suggests that the two isoforms together play an important role in vesicular glutamate transport in glutamatergic neurons.Neurotransmission depends on the regulated exocytotic release of vesicular transmitter molecules to the synaptic cleft, where they interact with postsynaptic receptors that subsequently transduce the information. Two types of neurotransmitter transporters have been identified based on membrane localization on plasma membrane or vesicular membrane. Removal of the transmitter from the synaptic cleft results in termination of the signal, and this requires destruction of transmitter or reuptake of transmitter back to the presynaptic terminal or glial cells via a sodium-dependent uptake system on the plasma membrane (1). Packaging and storage of neurotransmitters into specialized secretory vesicles in neurons ensures their regulated release. This storage is also crucial for protecting the neurotransmmitter molecules from leakage or intraneuronal metabolism and for protecting the neuron from possible toxic effects. This process is mediated by specific transporters on the vesicular membranes. At least four different types of vesicular transporters have been functionally identified that are specific for transport of classic neurotransmitters: monoamines, acetylcholine, ␥-aminobutyric acid (GABA), and glutamate (2, 3). Unlike the plasma membrane transporters, which rely on a sodium gradient across the plasma membrane, all of these vesicular transport processes depend on the proton electrochemical gradient (⌬ Hϩ ) 1 generated by a Mg 2ϩ -activated vacuolar H ϩ -ATPase (V-ATPase) on the vesicular membrane (4). When protons are pumped into the vesicular lumen, a proton gradient (⌬pH) and a membrane potential (⌬) occur across the membrane to form ⌬ Hϩ, which favors the exchange of luminal protons for cytoplasmic transmitter. The transport of monoamines and acetylcholine rely predominantly on ...

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Section: Molecularsupporting

confidence: 82%

Section: Discussionmentioning

confidence: 99%

Section: Molecularmentioning

confidence: 99%

See 1 more Smart Citation

Molecular and Functional Analysis of a Novel Neuronal Vesicular Glutamate Transporter

Bai¹,

Collins

et al. 2001

Journal of Biological Chemistry

189

138

View full text Add to dashboard Cite

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“…As discussed above, this specificity is imposed at the synaptic vesicle membrane. Thus in contrast to the numerous reports of glutamate uptake into synaptic vesicle preparations Ueda, 1983,1985;Fischer-Bovenkerk et al, 1988;Maycox et al, 1988;Shioi et al, 1989;Kish et al, 1989a;Carlson et al, 1989;Shioi and Ueda, 1990;Lobur et al, 1990) no evidence for vesicular aspartate uptake has been presented. Furthermore, synaptic vesicles isolated in the presence of N-ethylmaleimide contain no detectable aspartate (Burger et al, 1989).…”

Section: The Vesicular Transporter and Discrimination Between Glutamamentioning

confidence: 68%

The glutamatergic nerve terminal

Nicholls

1993

European Journal of Biochemistry

208

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Glutamate as a neurotransmitterThe human brain has about lolo neurones, each of which, on average, makes about 1000 synaptic contacts with other neurones. Of these l O I 3 synapses perhaps up to 90% utilize amino acids as their neurotransmitter. Glutamate is the major excitatory amino acid (acting predominantly on depolarizing post-synaptic receptors) while 4-aminobutyrate (GABA) and glycine are the major inhibitory transmitters (acting on hyper-polarizing receptors). As well as playing the dominant role in fast information transfer, glutamate is of particular interest in view of its involvement in current models of memory and learning (Bliss and Dolphin, 1982;Cotman et al., 1988;Collingridge and Singer, 1990) and because a pathological release of glutamate in brain ischaemia is neurotoxic and a major contributor to the damage caused under these conditions (Rothman and Olney, 1986;Choi, 1988 ;Meldrum and Garthwaite, 1990).A synapse has a pre-synaptic element responsible for the storage and release of transmitter and a post-synaptic element containing one or more classes of receptor for the transmitter. The potent combination of electrophysiology and molecular cloning has allowed a dramatic advance in our understanding of post-synaptic events. Three classes of post-synaptic ionotropic (possessing an integral ion channel) glutamate receptors have been identified and cloned: the 2-amino-3-hydroxy-5-methyl-4-isoxazole propionatekainate (AMPA/ KA) receptor Nakanishi et al., 1990;Sakmann, 1992), the high-affinity KA receptor (Egebjerg et al., 1991) and the N-methyl D-aSpartate (NMDA) receptor (Moriyoshi et al., 1991 ; Kumar et al., 1991 ;Barnard, 1992). Each can exist in many isoforms by combining subunits formed from distinct genes, by alternative splicing or by post-transcriptional modification (Monyer et al., 1991 ;Burnashev et al., 1992).The AMPNKA receptor is responsible for fast information transfer while the NMDA receptor is only operative when the post-synaptic membrane is independently depolarized by another receptor. This 'associative' behaviour of the latter is believed to underlie aspects of the learning process.

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“…Another feature of the vesicular glutamate transporter that segregates it from other neurotransmitter transporters is the marked stimulation seen in the presence of low concentrations of chloride (3,10,11,24,29). At low concentrations (1-5 mM), chloride stimulates transport, whereas at higher concentrations (above 10 mM), chloride inhibits transport.…”

Section: Functional Characterization Of Vesicular Glutamate Transportmentioning

confidence: 99%

Characterization of vesicular glutamate transporter in pancreatic α- and β-cells and its regulation by glucose

Bai

Zhang

2003

American Journal of Physiology-Gastrointestinal and Liver Physi

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.-Glutamate has been suggested to play an important role in the release of insulin and glucagon from pancreatic cells via exocytosis. Vesicular glutamate transporter is a rate-limiting step for glutamate release and is involved in the glutamate-evoked exocytosis. Two vesicular glutamate transporters (VGLUT1 and -2) have recently been cloned from the brain. In this report, we first functionally characterized vesicular glutamate transporter in cultured pancreatic ␣-and ␤-cells, and then detected mRNA expression of VGLUT1 and -2 in these cells. We also investigated the effect of high or low level of glucose on vesicular glutamate transport in cultured pancreas cells. Our results suggest that both ␣-and ␤-cells contain functional vesicular glutamate transporter. The transport characteristics are similar to the cloned neuronal VGLUT1 and -2 in regard to ATP dependence, substrate specificity, kinetics, and chloride dependence. VGLUT2 mRNA is expressed in both ␣-and ␤-cells, whereas VGLUT1 is only expressed in ␤-cells. High (12.8 mM) and low (2.8 mM) concentrations of glucose increased vesicular glutamate transport in ␤-and ␣-cells, respectively. VGLUT2 mRNA was significantly increased in ␤-and ␣-cells by high and low glucose concentration, respectively. This increase in VGLUT2 mRNA was suppressed by actinomycin D. We conclude that both ␣-and ␤-cells possess functional vesicular glutamate transporters regulated by alteration in glucose concentration, partly via the transcriptional mechanism. diabetes; insulin; glucagon; transcriptional regulation L-GLUTAMATE IS THE MAJOR EXCITATORY neurotransmitter in the mammalian central nervous system and plays important roles in many neuronal processes, such as fast synaptic transmission and neuronal plasticity. More recently, it has been suggested that glutamate is a functional molecule in nonneuronal tissues including pancreas, bone, stomach, intestine, liver, lung, kidney, and skin (28). Glutamate has been found to stimulate insulin (5, 7) and glucagon (6, 17) secretion in the pancreatic ␤-and ␣-cells, respectively. In the model of glucose-induced insulin secretion, increased cytosolic Ca 2ϩ concentration by the opening of voltage-sensitive Ca 2ϩ channels, constitutes the main trigger of insulin exocytosis. However, the Ca 2ϩ signal alone is not sufficient for the full development of biphasic insulin secretion (see Ref. 20 for review). Maechler and Wollheim (19) recently provided evidence that glutamate acts downstream of the mitochondria by sensitizing the Ca 2ϩ -mediated exocytotic process. In that model, a rise in extracellular glucose causes elevation of intracellular glucose followed by a subsequent increase in glycolysis and tricarboxylic acid activity. These metabolic changes lead to an increase in cellular ATP that closes ATP-sensitive potassium channels causing depolarization of the plasma membrane potential. Subsequently, depolarization opens voltage-sensitive Ca 2ϩ channels, raising intracellular Ca 2ϩ concentration and triggering insulin exocytosis. Glutamate is pack...

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ATP‐Dependent Glutamate Uptake into Synaptic Vesicles from Cerebellar Mutant Mice

Cited by 40 publications

References 41 publications

Molecular and Functional Analysis of a Novel Neuronal Vesicular Glutamate Transporter

Molecular and Functional Analysis of a Novel Neuronal Vesicular Glutamate Transporter

The glutamatergic nerve terminal

Characterization of vesicular glutamate transporter in pancreatic α- and β-cells and its regulation by glucose

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