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Na+-coupled neutral amino acid transporter 1 (amino acid transporter A1, N-system amino acid transporter 2, system A amino acid transporter 1, system N amino acid transporter 1, solute carrier family 38 member 1, SLC38A1, ATA1, NAT2, SAT1, SNAT1)
Function:
- Na+-dependent amino acid transporter
- mediates saturable, pH-sensitive & electrogenic cotransport of glutamine & Na+ ions with a stoichiometry of 1:1
- may also transport small zwitterionic & aliphatic amino acids with a lower affinity
- may supply glutamatergic & GABAergic neurons with glutamine which is required for the synthesis of the neurotransmitters glutamate & GABA
- inhibited by K+, choline ions & 2- methylamino-isobutyric acid (MeAIB) (putative)
- inhibited by Li+ & N-methyl-D-glucamine
Kinetic parameters:
- KM=890 uM for MeAIB (at pH 8.5)
Structure:
- belongs to the amino acid/polyamine transporter 2 family
Compartment:
- cell membrane
- restricted to the somatodendritic compartment of neurons
- found in the cellular processes of neurons in the developing brain
Expression:
- expressed in cerebral cortex by pyramidal & GABAergic neurons, astrocytes & other non-neuronal cells (at protein level)
- expressed in placenta, heart, lung, skeletal muscle, spleen, stomach & testis
- down-regulated by lipopolysaccharides in glial cells
- down-regulated upon hypoxia
General
glycoprotein
phosphoprotein
solute carrier family 38 (SLC38, SLC38A)
transmembrane 11 protein
Properties
SIZE: entity length = 487 aa
MW = 54 kD
COMPARTMENT: cellular membrane
MOTIF: cytoplasmic domain {1-74}
MOTIF: Ser phosphorylation site {S49}
Thr phosphorylation site {T54}
transmembrane domain {75-97}
exoplasmic loop {98-112}
transmembrane domain {113-133}
cytoplasmic loop {134-147}
transmembrane domain {148-168}
exoplasmic loop {169-188}
transmembrane domain {189-211}
cytoplasmic loop {212-216}
transmembrane domain {217-237}
exoplasmic loop {238-275}
MOTIF: N-glycosylation site {N251}
N-glycosylation site {N257}
transmembrane domain {276-296}
cytoplasmic loop {297-312}
transmembrane domain {313-333}
exoplasmic loop {334-350}
transmembrane domain {351-371}
cytoplasmic loop {372-393}
transmembrane domain {394-414}
exoplasmic loop {415-416}
transmembrane domain {417-437}
cytoplasmic loop {438-452}
transmembrane domain {453-473}
exoplasmic domain {474-487}
Database Correlations
OMIM 608490
UniProt Q9H2H9
Pfam PF01490
References
UniProt :accession Q9H2H9