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- Schlessinger, Avner, et al.
(author)
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Comparison of human solute carriers
- 2010
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In: Protein Science. - : Wiley. - 0961-8368 .- 1469-896X. ; 19:3, s. 412-428
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Journal article (peer-reviewed)abstract
- Solute carriers are eukaryotic membrane proteins that control the uptake and efflux of solutes, including essential cellular compounds, environmental toxins, and therapeutic drugs. Solute carriers can share similar structural features despite weak sequence similarities. Identification of sequence relationships among solute carriers is needed to enhance our ability to model individual carriers and to elucidate the molecular mechanisms of their substrate specificity and transport. Here, we describe a comprehensive comparison of solute carriers. We link the proteins using sensitive profile-profile alignments and two classification approaches, including similarity networks. The clusters are analyzed in view of substrate type, transport mode, organism conservation, and tissue specificity. Solute carrier families with similar substrates generally cluster together, despite exhibiting relatively weak sequence similarities. In contrast, some families cluster together with no apparent reason, revealing unexplored relationships. We demonstrate computationally and experimentally the functional overlap between representative members of these families. Finally, we identify four putative solute carriers in the human genome. The solute carriers include a biomedically important group of membrane proteins that is diverse in sequence and structure. The proposed classification of solute carriers, combined with experiment, reveals new relationships among the individual families and identifies new solute carriers. The classification scheme will inform future attempts directed at modeling the structures of the solute carriers, a prerequisite for describing the substrate specificities of the individual families.
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| 2. |
- Ahlin, Gustav, 1977-, et al.
(author)
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Genotype-dependent effects of inhibitors of the organic cation transporter, OCT1: : predictions of metformin interactions
- 2011
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In: The Pharmacogenomics Journal. - : Springer Science and Business Media LLC. - 1470-269X .- 1473-1150. ; 11:6, s. 400-411
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Journal article (peer-reviewed)abstract
- Common genetic variants of the liver-specific human organic cation transporter 1 (OCT1; SLC22A1) have reduced transport capacity for substrates such as the antidiabetic drug metformin. The effect of the reduced OCT1 function on drug interactions associated with OCT1 has not been investigated and was, therefore, the focus of the study presented here. HEK293 cells expressing human OCT1-reference or the variants R61C, V408M, M420del and G465R were first used to study the kinetics and inhibition pattern of the OCT1 substrate 4-(4-(dimethylamino)styryl)-N-methylpyridinium (ASP(+)). In the second part OCT1-mediated (14)C-metformin uptake was studied in the presence of drugs administered concomitantly with metformin. Transport studies using ASP(+) showed that the function of the variants decreased in the following order: OCT1-reference = V408M = M420del >R61C > >G465R. Variants M420del and R61C were more sensitive to drug inhibition, with IC(50) values up to 23 times lower than those of the OCT1-reference. Uptake studies using (14)C-metformin were in qualitative agreement with those using ASP(+), with the exception that a larger reduction in transport capacity was observed for M420del. Concomitantly administered drugs, such as verapamil and amitriptyline, revealed potential drug-drug interactions at clinical plasma concentrations of metformin for OCT1-M420del.
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| 3. |
- Kido, Yasuto, et al.
(author)
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Profiling of a prescription drug library for potential renal drug-drug interactions mediated by the organic cation transporter 2
- 2011
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In: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 54:13, s. 4548-4558
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Journal article (peer-reviewed)abstract
- Drug-drug interactions (DDIs) are major causes of serious adverse drug reactions. Most DDIs have a pharmacokinetic basis in which one drug reduces the elimination of a second drug, leading to potentially toxic drug levels. As a major organ of drug elimination, the kidney represents an important site for DDIs. Here, we screened a prescription drug library against the renal organic cation transporter OCT2/SLC22A2, which mediates the first step in the renal secretion of many cationic drugs. Of the 910 compounds screened, 244 inhibited OCT2. Computational analyses revealed key properties of inhibitors versus noninhibitors, which included overall molecular charge. Four of six potential clinical inhibitors were transporter-selective in follow-up screens against additional transporters: OCT1/SLC22A1, MATE1/SLC47A1, and MATE2-K/SLC47A2. Two compounds showed different kinetics of interaction with the common polymorphism OCT2-A270S, suggesting a role of genetics in modulating renal DDIs.
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