Cloning and characterization of a brain-specific cationic amino acid transporter.

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Hosokawa H, Sawamura T, Kobayashi S, Ninomiya H, Miwa S, Masaki T

Cloning and characterization of a brain-specific cationic amino acid transporter.

J Biol Chem. 1997 Mar 28;272(13):8717-22.

PubMed ID

9079705 [ View in PubMed

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Abstract

rCAT3 (rat cationic amino acid transporter 3), a cDNA that encodes a novel member of the murine CAT family was isolated. The protein encoded by rCAT3 contained 619 amino acids, 53-58% of which were identical with those of the murine CAT family proteins previously described (mouse CAT1, CAT2a, CAT2b, and rat CAT1). Transient expression of rCAT3 and L-[14C]arginine incorporation experiments in COS7 cells verified a high affinity system y+ transporter activity of rCAT3. First, rCAT3-mediated L-[14C]arginine incorporation was time-dependent and saturable with half-saturation constant (Km) values of 103 +/- 12 microM (mean +/- S.E., n = 3). Second, the incorporation was specific for cationic amino acids as evidenced from the inhibition by L-arginine, L-lysine, and L-ornithine. Third, neither sodium nor chloride ions in the extracellular medium were required for the activity. Fourth, the incorporation was inhibited by high potassium-induced membrane depolarization. On Northern blot using RNAs from various rat tissues, the expression of rCAT3 mRNA was restricted to the brain. These results indicated a role of rCAT3 in the system y+ transporter activity in the nervous tissue.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Lysine	Cationic amino acid transporter 3	Protein	Humans	Unknown	Not Available	Details