TY - JOUR
T1 - Expression of a mouse brain cDNA encoding novel γ-aminobutyric acid transporter
AU - Nelson, Nathan
AU - Lopez-Corcuera, Beatriz
AU - Liu, Qing Rong
AU - Mandiyan, Sreekala
AU - Nelson, Hannah
PY - 1992/9/5
Y1 - 1992/9/5
N2 - A nipecotic acid-resistant γ-aminobutyric acid (GABA) transporter was cloned from a mouse brain cDNA library. The 2.3-kilobase cDNA clone contains an open reading frame of 1842 nucleotides encoding a protein of 614 amino acids. The predicted amino acid sequence indicates it is a member of the gene family of the sodium-dependent neurotransmitter transporters. The new GABA transporter, named GAT2, is highly homologous to the betaine transporter (BGT1) cloned from canine kidney. However, GAT2 expression in the brain distinguished it from BGT1 which was exclusively expressed in the kidney. The transcripts of GAT2 were found in the cerebral cortex, cerebellum, and brainstem as well as in kidney. Expression of GAT2 in Xenopus oocytes revealed a Km of 79 μM for GABA uptake which is about 10-fold higher than that of the high affinity GABA transporter (GAT1). The pharmacology of GAT2 is different from that of GAT1 because of lack of inhibition by guvacine and nipecotic acid and sensitivity to high concentrations of betaine and β-alanine. GAT2 transports betaine with a Km of about 200 μM, but no significant transport of β-alanine could be detected. The presence of mRNA encoding GAT2 in parts of the brain suggests it is a neurotransmitter transporter.
AB - A nipecotic acid-resistant γ-aminobutyric acid (GABA) transporter was cloned from a mouse brain cDNA library. The 2.3-kilobase cDNA clone contains an open reading frame of 1842 nucleotides encoding a protein of 614 amino acids. The predicted amino acid sequence indicates it is a member of the gene family of the sodium-dependent neurotransmitter transporters. The new GABA transporter, named GAT2, is highly homologous to the betaine transporter (BGT1) cloned from canine kidney. However, GAT2 expression in the brain distinguished it from BGT1 which was exclusively expressed in the kidney. The transcripts of GAT2 were found in the cerebral cortex, cerebellum, and brainstem as well as in kidney. Expression of GAT2 in Xenopus oocytes revealed a Km of 79 μM for GABA uptake which is about 10-fold higher than that of the high affinity GABA transporter (GAT1). The pharmacology of GAT2 is different from that of GAT1 because of lack of inhibition by guvacine and nipecotic acid and sensitivity to high concentrations of betaine and β-alanine. GAT2 transports betaine with a Km of about 200 μM, but no significant transport of β-alanine could be detected. The presence of mRNA encoding GAT2 in parts of the brain suggests it is a neurotransmitter transporter.
UR - http://www.scopus.com/inward/record.url?scp=0026699641&partnerID=8YFLogxK
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AN - SCOPUS:0026699641
SN - 0021-9258
VL - 267
SP - 17491
EP - 17493
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 25
ER -