title: Molecular characterization of two novel transporters from human and mouse kidney and from LLC-PK1 cells reveals a novel conserved family that is homologous to bacterial and Aspergillus nucleobase transporters.
abstract: Nucleobase transport is important for the metabolism of nucleic acids and antiviral and antineoplastic drugs. This transport has been functionally described in several mammalian cells but has not been well characterized molecularly. We report the cloning of two novel transporters. YSPL2 encodes a 650-residue protein and has an ubiquitous 8 kb transcript. The human and pig homologs are 95% similar. YSPL3 encodes a 598-residue protein with a 3 kb transcript that is expressed only in kidney and liver. Human YSPL2 and YSPL3 are 60% similar at the amino acid level and both show 31% similarity to the first nucleobase permease gene described in vertebrates, YSPL1. These proteins appear to be members of a new family of possible nucleobase transporters with significant sequence similarities with bacterial and Aspergillus nucleobase transporters. Further functional studies will be needed to unveil the role of these transporters in nucleic acid metabolism in normal and in disease states.
authors.affiliation: Renal Division, Department of Medicine, SUNY-Health Science Center, Syracuse, NY, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Faaland
authors.forename: J E
authors.initials: JE
authors.lastname: Race
authors.forename: G
authors.initials: G
authors.lastname: Ricken
authors.forename: F J
authors.initials: FJ
authors.lastname: Warner
authors.forename: W J
authors.initials: WJ
authors.lastname: Williams
authors.forename: E J
authors.initials: EJ
authors.lastname: Holtzman
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001230:Aspergillus / Q000235:genetics / Q000378:metabolism; D001419:Bacteria / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics*; D017124:Conserved Sequence; D019143:Evolution, Molecular; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D018374:LLC-PK1 Cells; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000235:genetics*; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D029363:Organic Anion Transporters, Sodium-Dependent; D010802:Phylogeny; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D060347:Sodium-Coupled Vitamin C Transporters; D013552:Swine; D027981:Symporters; D014158:Transcription, Genetic; D014714:Vertebrates
chemical_list: D002352:Carrier Proteins; D026901:Membrane Transport Proteins; D029363:Organic Anion Transporters, Sodium-Dependent; C555162:SLC23A1 protein, human; C555163:SLC23A2 protein, human; C555164:Slc23a1 protein, mouse; D060347:Sodium-Coupled Vitamin C Transporters; D027981:Symporters