Cloning and characterization of a human brain Na(+)-independent transporter for small neutral amino acids that transports D-serine with high affinity.
We isolated a cDNA for the human homologue of system asc transporter Asc-1 from human brain. The encoded protein designated as hAsc-1 (human Asc-1) exhibited 91 % sequence identity to mouse Asc-1. Consistent with mouse Asc-1, hAsc-1 required 4F2 heavy chain for its functional expression in Xenopus oocytes. hAsc-1 exhibited the properties of amino acid transport system asc which transports small neutral amino acids in a Na(+)-independent manner. hAsc-1 transported D-serine at high affinity with a K(m) value of 22.8 microM. In brain, 2.0 kb mRNA was highly expressed. hAsc-1 gene was mapped to human chromosome 19, region q12-q13.1. Because of the high-affinity transport with the K(m) value close to the physiological concentration of D-serine, together with the high levels of expression in brain, hAsc-1 is proposed to play significant roles in the D-serine mobilization in brain.
Nakauchi
J
J
Department of Neurosurgery, Kyorin University School of Medicine, Tokyo, Japan.
Matsuo
H
H
Kim
D K
DK
Goto
A
A
Chairoungdua
A
A
Cha
S H
SH
Inatomi
J
J
Shiokawa
Y
Y
Yamaguchi
K
K
Saito
I
I
Endou
H
H
Kanai
Y
Y
D027182:Amino Acid Transport System y+; D026905:Amino Acid Transport Systems; D000818:Animals; D015152:Blotting, Northern; D001923:Brain Chemistry; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism*; D002874:Chromosome Mapping; D002888:Chromosomes, Human, Pair 19; D003001:Cloning, Molecular; D018076:DNA, Complementary; D015870:Gene Expression / Q000502:physiology; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D051379:Mice; D008969:Molecular Sequence Data; D009865:Oocytes / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012694:Serine / Q000378:metabolism*; D014981:Xenopus
D027182:Amino Acid Transport System y+; D026905:Amino Acid Transport Systems; D002352:Carrier Proteins; D018076:DNA, Complementary; D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate; C498799:SLC7A10 protein, human; C412624:Slc7a10 protein, mouse; D012694:Serine