Cloning and expression of a rat brain L-glutamate transporter.
Synaptic transmission of most vertebrate synapses is thought to be terminated by rapid transport of the neurotransmitter into presynaptic nerve terminals or neuroglia. L-Glutamate is the major excitatory transmitter in brain and its transport represents the mechanism by which it is removed from the synaptic cleft and kept below toxic levels. Here we use an antibody against a glial L-glutamate transporter from rat brain to isolate a complementary DNA clone encoding this transporter. Expression of this cDNA in transfected HeLa cells indicates that L-glutamate accumulation requires external sodium and internal potassium and transport shows the expected stereospecificity. The cDNA sequence predicts a protein of 573 amino acids with 8-9 putative transmembrane alpha-helices. Database searches indicate that this protein is not homologous to any identified protein of mammalian origin, including the recently described superfamily of neurotransmitter transporters. This protein therefore seems to be a member of a new family of transport molecules.
Pines
G
G
Department of Biochemistry, Hadassah Medical School, Hebrew University, Jerusalem, Israel.
Danbolt
N C
NC
Bjørås
M
M
Zhang
Y
Y
Bendahan
A
A
Eide
L
L
Koepsell
H
H
Storm-Mathisen
J
J
Seeberg
E
E
Kanner
B I
BI
D000595:Amino Acid Sequence; D027322:Amino Acid Transport System X-AG; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D001921:Brain / Q000378:metabolism*; D003001:Cloning, Molecular / Q000379:methods; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D004926:Escherichia coli / Q000235:genetics; D015723:Gene Library; D005971:Glutamates; D006023:Glycoproteins / Q000235:genetics* / Q000378:metabolism*; D007700:Kinetics; D008961:Models, Structural; D008969:Molecular Sequence Data; D011487:Protein Conformation; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification; D051381:Rats; D017386:Sequence Homology, Amino Acid
D027322:Amino Acid Transport System X-AG; D005971:Glutamates; D006023:Glycoproteins; D012333:RNA, Messenger; D004247:DNA