| TCID | Name | Domain | Kingdom/Phylum | Protein(s) |
|---|---|---|---|---|
|
1.A.28.1.1 | Kidney vasopressin regulated urea transporter, UT-A2 (splice variant of UT-A1) | Eukaryota |
Metazoa, Chordata | UT-A2 of Rattus norvegicus |
|
1.A.28.1.2 | Frog urinary bladder ADH-regulated urea transporter | Eukaryota |
Metazoa | Urea transporter of Rana esculenta (O57609) |
|
1.A.28.1.3 | Kidney urea transporter, UT-A1, of 414aas and 11 TMSs in a 5 + 5 + 1 TMS arrangement. It mediates transepithelial urea transport in the inner medullary collecting duct for urinary concentration. Interacts with the C-terminus of Snapin (O95295) and SNARE-associated protein) (Mistry et al., 2007). Also transports formamide, acetamide, methylurea, methylformamide, ammonium carbamate, and acrylamide, and possibly dimethylurea and thiourea as well (Zhao et al., 2007). Mutation of the N-linked glycosylation sites reduces urea flux by reducing the UT-A1 half-life and decreasing its accumulation in the apical plasma membrane. The related erythrocyte urea transporter, UTB (UT-B; TC# 1.A.28.1.5) has been reviewed (Bagnasco, 2006). Mutation of the N-linked glycosylation sites reduces urea flux by reducing the UT-A1 half-life and decreasing its accumulation in the apical plasma membrane (Chen et al. 2006). In vivo, inner medullary collecting duct cells may thus regulate urea uptake by altering UT-A1 glycosylation in response to AVP stimulation. | Eukaryota |
Metazoa, Chordata | UT-A1 of Rattus norvegicus |
|
1.A.28.1.4 | THe urea transporter channel protein of 337 aas and 11 TMSs in an apparent 6 + 5 TMS arrangement. The 3-d structure (2.3 Å resolution) is available (Levin et al., 2009). Urea binding and flux as well as dimethylurea (DMU) transport have been modeled (Zhang et al. 2017). | Bacteria |
Thermodesulfobacteriota | Urea channel of Desulfovibrio vulgaris (A1VEP3) |
|
1.A.28.1.5 | Urea transporter 1 or UT-B1 (Solute carrier family 14 member 1; Urea transporter of the erythrocyte) (Bagnasco 2006). A phenylphthalazine compound, PU1424, is a potent UT-B inhibitor, inhibiting human and mouse UT-B-mediated urea transport with IC50 values of 0.02 and 0.69 mumol/L, respectively, and exerted 100% UT-B inhibition at high concentrations (Ran et al. 2016). Another potent inhibitor is the thienopyridine, CB-20 (5-ethyl-2-methyl-3-amino-6-methylthieno[2,3-b]pyridine-2,5-dicarboxylate) (Li et al. 2019). UT-B catalyzes transmembrane water transport which can be ued as a reporter system (Schilling et al. 2016). Knocking out both UT1 and UT2 increases urine output 3.5-fold and lowers urine osmolarity (Jiang et al. 2016). The double knockout also lowered blood pressure and promoted maturation of the male reproductive system. Thus, functional deficiency of all UTs causes a urea-selective urine-concentrating defect with few physiological abnormalities in extrarenal organs (Jiang et al. 2016). UT-B may be related to the occurrence of melanoma and play a role in tumor development (Liu et al. 2018). | Eukaryota |
Metazoa, Chordata | SLC14A1 of Homo sapiens |
|
1.A.28.1.6 | Urea transporter 2, UT2, HUT2 or UTB (Solute carrier family 14 member 2) (Urea transporter, kidney). Knocking out both UT1 and UT2 increases urine output 3.5-fold and lowers urine osmolarity (Jiang et al. 2016). The double knockout also lowered blood pressure and promoted maturation of the male reproductive system. Thus, functional deficiency of all UTs causes a urea-selective urine-concentrating defect with few physiological abnormalities in extrarenal organs (Jiang et al. 2016). A potent inhibitor of both UT1 and UT2 is the thienopyridine, CB-20 (5-ethyl-2-methyl-3-amino-6-methylthieno[2,3-b]pyridine-2,5-dicarboxylate) (Li et al. 2019). UTB is downregulated in polycythemia vera hematopoietic stem and progenitor cell subpopulations (Tan and Meier-Abt 2021). Urea transporter B downregulates polyamines levels in melanoma B16 cells via p53 activation (Li et al. 2022). | Eukaryota |
Metazoa, Chordata | SLC14A2 of Homo sapiens |
|
1.A.28.1.7 | Putative urea transporter of 306 aas and 9 or 10 TMSs | Bacteria |
Pseudomonadota | UT of E. coli |
|
1.A.28.2.1 | The dimeric urea transporter, Utp of 300 aas and 9 or probably 10 TMSs. Urea flux is saturable, could be inhibited by phloretin, and was not affected by pH (Raunser et al., 2009) | Bacteria |
Pseudomonadota | Utp of Actinobacillus pleuropneumoniae |