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MGP005738

UniProt Annotations

Entry Information
Gene Namesolute carrier family 28 (concentrative nucleoside transporter), member 3
Protein EntryS28A3_HUMAN
UniProt IDQ9HAS3
SpeciesHuman
Comments
Comment typeDescription
Alternative ProductsEvent=Alternative splicing; Named isoforms=2; Name=1; IsoId=Q9HAS3-1; Sequence=Displayed; Name=2; Synonyms=hCNT3ins; IsoId=Q9HAS3-2; Sequence=VSP_053848; Note=Exhibits a shorter half-life than isoform 1, degraded via a proteasome-dependent pathway.;
Biophysicochemical PropertiesKinetic parameters: KM=21.6 uM for uridine {ECO:0000269|PubMed:11032837, ECO:0000269|PubMed:15861042}; KM=15.4 uM for cytidine {ECO:0000269|PubMed:11032837, ECO:0000269|PubMed:15861042}; KM=21.2 uM for thymidine {ECO:0000269|PubMed:11032837, ECO:0000269|PubMed:15861042}; KM=15.1 uM for adenosine {ECO:0000269|PubMed:11032837, ECO:0000269|PubMed:15861042}; KM=43 uM for guanosine {ECO:0000269|PubMed:11032837, ECO:0000269|PubMed:15861042}; KM=52.5 uM for inosine {ECO:0000269|PubMed:11032837, ECO:0000269|PubMed:15861042}; Vmax=25.8 pmol/min/mg enzyme for uridine uptake {ECO:0000269|PubMed:11032837, ECO:0000269|PubMed:15861042}; Vmax=32.8 pmol/min/mg enzyme for cytidine uptake {ECO:0000269|PubMed:11032837, ECO:0000269|PubMed:15861042}; Vmax=24.2 pmol/min/mg enzyme for thymidine uptake {ECO:0000269|PubMed:11032837, ECO:0000269|PubMed:15861042}; Vmax=30.4 pmol/min/mg enzyme for adenosine uptake {ECO:0000269|PubMed:11032837, ECO:0000269|PubMed:15861042}; Vmax=51.4 pmol/min/mg enzyme for guanosine uptake {ECO:0000269|PubMed:11032837, ECO:0000269|PubMed:15861042}; Vmax=44.8 pmol/min/mg enzyme for inosine uptake {ECO:0000269|PubMed:11032837, ECO:0000269|PubMed:15861042};
FunctionSodium-dependent, pyrimidine- and purine-selective. Involved in the homeostasis of endogenous nucleosides. Exhibits the transport characteristics of the nucleoside transport system cib or N3 subtype (N3/cib) (with marked transport of both thymidine and inosine). Employs a 2:1 sodium/nucleoside ratio. Also able to transport gemcitabine, 3'-azido-3'-deoxythymidine (AZT), ribavirin and 3-deazauridine. {ECO:0000269|PubMed:11032837, ECO:0000269|PubMed:16446384, ECO:0000269|PubMed:17140564}.
InductionUp-regulated by phorbol myristate acetate (PMA) in HL- 60 cells. {ECO:0000269|PubMed:11032837}.
SimilarityBelongs to the concentrative nucleoside transporter (CNT) (TC 2.A.41) family. {ECO:0000305}.
Subcellular LocationIsoform 1: Cell membrane; Multi-pass membrane protein.
Subcellular LocationIsoform 2: Endoplasmic reticulum membrane; Multi-pass membrane protein.
Tissue SpecificityExpressed in pancreas, bone marrow, trachea, mammary gland, liver, prostate, and regions of intestine, brain, lung, placenta, testis, kidney, and heart. {ECO:0000269|PubMed:11032837}.
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