MGP Database

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MGP002908

UniProt Annotations

Entry Information
Gene Namesolute carrier family 22 (organic cation transporter), member 1
Protein EntryS22A1_HUMAN
UniProt IDO15245
SpeciesHuman
Comments
Comment typeDescription
Alternative ProductsEvent=Alternative splicing; Named isoforms=4; Name=1; Synonyms=hOCT1G/L554; IsoId=O15245-1; Sequence=Displayed; Name=2; Synonyms=hOCT1G/L506; IsoId=O15245-2; Sequence=VSP_033589, VSP_033590; Name=3; Synonyms=hOCT1G483; IsoId=O15245-3; Sequence=VSP_033588; Name=4; Synonyms=hOCT1G353; IsoId=O15245-4; Sequence=VSP_033587; Note=May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay.;
Biophysicochemical PropertiesKinetic parameters: KM=1.47 mM for metformin {ECO:0000269|PubMed:16272756, ECO:0000269|PubMed:9187257, ECO:0000269|PubMed:9655880}; KM=229 uM for TEA {ECO:0000269|PubMed:16272756, ECO:0000269|PubMed:9187257, ECO:0000269|PubMed:9655880}; KM=14.6 uM for MPP {ECO:0000269|PubMed:16272756, ECO:0000269|PubMed:9187257, ECO:0000269|PubMed:9655880}; Vmax=396 pmol/min/mg enzyme for metformin uptake {ECO:0000269|PubMed:16272756, ECO:0000269|PubMed:9187257, ECO:0000269|PubMed:9655880}; Vmax=2.89 nmol/min/mg enzyme for TEA uptake {ECO:0000269|PubMed:16272756, ECO:0000269|PubMed:9187257, ECO:0000269|PubMed:9655880};
FunctionTranslocates a broad array of organic cations with various structures and molecular weights including the model compounds 1-methyl-4-phenylpyridinium (MPP), tetraethylammonium (TEA), N-1-methylnicotinamide (NMN), 4-(4-(dimethylamino)styryl)- N-methylpyridinium (ASP), the endogenous compounds choline, guanidine, histamine, epinephrine, adrenaline, noradrenaline and dopamine, and the drugs quinine, and metformin. The transport of organic cations is inhibited by a broad array of compounds like tetramethylammonium (TMA), cocaine, lidocaine, NMDA receptor antagonists, atropine, prazosin, cimetidine, TEA and NMN, guanidine, cimetidine, choline, procainamide, quinine, tetrabutylammonium, and tetrapentylammonium. Translocates organic cations in an electrogenic and pH-independent manner. Translocates organic cations across the plasma membrane in both directions. Transports the polyamines spermine and spermidine. Transports pramipexole across the basolateral membrane of the proximal tubular epithelial cells. The choline transport is activated by MMTS. Regulated by various intracellular signaling pathways including inhibition by protein kinase A activation, and endogenously activation by the calmodulin complex, the calmodulin- dependent kinase II and LCK tyrosine kinase. {ECO:0000269|PubMed:11388889, ECO:0000269|PubMed:11408531, ECO:0000269|PubMed:15389554, ECO:0000269|PubMed:16272756, ECO:0000269|PubMed:16581093, ECO:0000269|PubMed:9187257, ECO:0000269|PubMed:9260930, ECO:0000269|PubMed:9655880}.
InductionIn the liver activated by HNF4A and suppressed by bile acids via NR0B2. Increased by cholesterol treatment in hepatocyte cells. {ECO:0000269|PubMed:16436500, ECO:0000269|PubMed:17635184}.
InteractionQ96G23:CERS2; NbExp=3; IntAct=EBI-1172714, EBI-1057080;
PtmPhosphorylated. {ECO:0000250}.
SimilarityBelongs to the major facilitator (TC 2.A.1) superfamily. Organic cation transporter (TC 2.A.1.19) family. {ECO:0000305}.
Subcellular LocationBasolateral cell membrane {ECO:0000269|PubMed:16263091}; Multi-pass membrane protein {ECO:0000269|PubMed:16263091}.
Tissue SpecificityWidely expressed with high level in liver. Isoform 1 and isoform 2 are expressed in liver. Isoform 1, isoform 2, isoform 3 and isoform 4 are expressed in glial cell lines. {ECO:0000269|PubMed:11388889, ECO:0000269|PubMed:9187257, ECO:0000269|PubMed:9260930}.
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