Protein Domain : IPR018270

Type:  Family Name:  Concentrative nucleoside transporter, metazoan/bacterial
Description:  Nucleosides are hydrophilic molecules and require specialised transport proteins for permeation of cell membranes. There are two types of nucleoside transport processes: equilibrative bidirectional processes driven by chemical gradients and inwardly directed concentrative processes driven by an electrochemical gradient []. The two types of nucleoside transporters are classified into two families: the solute carrier (SLC) 29 and SLC28 families, corresponding to equilibrative and concentrative nucleoside transporters, respectively [].This entry represents a subgroup of Concentrative Nucleoside Transporter (CNT) proteins found in metazoa and bacteria. So far, the members found in microorganisms such as bacteria and fungi are H+ symporters, while the mammalian members are Na+ symporters.The microbial proteins include broad specificity transporters, such as the Escherichia coliNupC protein which transports all nucleosides (both ribo- and deoxyribonucleosides) except hypoxanthine and guanine nucleosides []. Other proteins have higher specificity, like the Bacillus subtilisNupC transporter which is specific for pyrimidine nucleosides (cytidine and uridine and the corresponding deoxyribonucleosides). A recently characterised fungal protein, the first transporter of this type to be described in eukaryotes, exhibited transport activity for adenosine, uridine, inosine and guanosine but not cytidine, thymidine or the nucleobase hypoxanthine [].The characterised mammalian proteins can be divided into three subgroups; CNT1, CNT2 and CNT3 []. CNT1 preferentially transports pyrimidines and weakly transports adenosine. Several antiviral and anticancer nucleoside analogues, including AZT and dFdC are also substrates for CNT1. CNT2 selectively transports purines, and the human form has also been shown to facilitate the uptake of some antiviral compounds including ddI and ribavirin. CNT3 has a broader specificity, transporting both purines and pyrimidines. Several anticancer nucleoside analogues such as CdA, dFdC and FdU are also transported by CNT3. Substrate specificity appears to depend on a region containing transmembrane regions 7, 8 and 9. Mutation of just four residues in this region was sufficient to convert the activity of human CNT1 to that of CNT2. At least three other concentrative nucleoside transport activities have been described in mammalian cells, but the proteins responsible for these activities have not yet been identified. Short Name:  C_nuclsd_transpt_met_bac
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3 Child Features

DB identifier Type Name
IPR030215 Family Concentrative nucleoside transporter, nematoda
IPR030211 Family Concentrative nucleoside transporter CNT3
IPR030212 Family Concentrative nucleoside transporter CNT1/CNT2

3 Contains

DB identifier Type Name
IPR011642 Domain Nucleoside transporter/FeoB GTPase, Gate domain
IPR011657 Domain Concentrative nucleoside transporter C-terminal domain
IPR002668 Domain Concentrative nucleoside transporter N-terminal domain

1 Cross References

Identifier
TIGR00804

0 Found In

3 GO Annotations

GO Term Gene Name
GO:0005415 IPR018270
GO:0006810 IPR018270
GO:0016020 IPR018270

3 Ontology Annotations

GO Term Gene Name
GO:0005415 IPR018270
GO:0006810 IPR018270
GO:0016020 IPR018270

1 Parent Features

DB identifier Type Name
IPR008276 Family Concentrative nucleoside transporter

2 Proteins

DB identifier UniProt Accession Secondary Identifier Organism Name Length
Brdisv1pangenome1007369m.p PAC:33607590 Brachypodium distachyon Pangenome 392  
Brdisv1BdTR11A1042243m.p PAC:35690454 Brachypodium distachyon BdTR11a 430  

5 Publications

First Author Title Year Journal Volume Pages PubMed ID
            10353709
            23506887
            15678184
            12794928
            16265592