title: Identification of multidrug and toxin extrusion (MATE1 and MATE2-K) variants with complete loss of transport activity.
abstract: H(+)/organic cation antiporters (multidrug and toxin extrusion: MATE1 and MATE2-K) play important roles in the renal tubular secretion of cationic drugs. We have recently identified a regulatory single nucleotide polymorphism (SNP) of the MATE1 gene (-32G>A). There is no other information about SNPs of the MATE gene. In this study, we evaluated the functional significance of genetic polymorphisms in MATE1 and MATE2-K. We sequenced all exons of MATE1 and MATE2-K genes in 89 Japanese subjects and identified coding SNPs (cSNPs) encoding MATE1 (V10L, G64D, A310V, D328A and N474S) and MATE2-K (K64N and G211V). All the variants except for MATE1 V10L showed significant decrease in transport activity. In particular, MATE1 G64D and MATE2-K G211V variants completely lost transport activities. When membrane expression level was evaluated by cell surface biotinylation, those of MATE1 (G64D and D328A) and MATE2-K (K64N and G211V) were significantly decreased compared with that of wild type. These findings suggested that the loss of transport activities of the MATE1 G64D and MATE2-K G211V variants were due to the alteration of protein expression in cell surface membranes. This is the first demonstration of functional impairment of the MATE family induced by cSNPs.
authors.affiliation: Department of Pharmacy, Kyoto University Hospital, Sakyo-ku, Kyoto, Japan.
authors.forename: Moto
authors.initials: M
authors.lastname: Kajiwara
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Terada
authors.forename: Ken
authors.initials: K
authors.lastname: Ogasawara
authors.forename: Junko
authors.initials: J
authors.lastname: Iwano
authors.forename: Toshiya
authors.initials: T
authors.lastname: Katsura
authors.forename: Atsushi
authors.initials: A
authors.lastname: Fukatsu
authors.forename: Toshio
authors.initials: T
authors.lastname: Doi
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Inui
mesh_terms: D000595:Amino Acid Sequence; D001692:Biological Transport; D019921:Biotinylation; D015153:Blotting, Western; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008687:Metformin / Q000378:metabolism; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000378:metabolism*; D027701:Organic Cation Transport Proteins / Q000737:chemistry / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D019789:Tetraethylammonium / Q000378:metabolism
chemical_list: D050505:Mutant Proteins; D027701:Organic Cation Transport Proteins; C521869:SLC47A1 protein, human; C521870:SLC47A2 protein, human; D019789:Tetraethylammonium; D008687:Metformin