1. Identification of competitive inhibitors of the human taurine transporter TauT in a human kidney cell line
- Author
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Michelle Richter, Hartmut Michel, and Selina J. Moroniak
- Subjects
Taurine ,animal structures ,Kidney ,Binding, Competitive ,Structure-Activity Relationship ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Membrane Transport Modulators ,Humans ,Viability assay ,Pharmacology ,Binding Sites ,Membrane Glycoproteins ,Molecular Structure ,HEK 293 cells ,Membrane Transport Proteins ,Biological Transport ,Transporter ,General Medicine ,Fusion protein ,Cell biology ,Kinetics ,HEK293 Cells ,chemistry ,Osmolyte ,Cell culture ,Homotaurine ,030220 oncology & carcinogenesis ,030217 neurology & neurosurgery ,Protein Binding - Abstract
Background The osmolyte and antioxidant taurine plays an important role in regulation of cellular volume, oxidative status and Ca2+-homeostasis. Taurine uptake in human cells is regulated by the Na+- and Cl−-dependent taurine transporter TauT. In order to gain deeper structural insights about the substrate binding pocket of TauT, a HEK293 cell line producing a GFP-TauT fusion protein was generated. Methods Transport activity was validated using cell-based [3H]-taurine transport assays. We determined the Km and IC50 values of taurine, β-alanine and γ-aminobutyrate. Additionally we were able to identify structurally similar compounds as potential new substrates or inhibitors of the TauT transporter. Substrate induced cytotoxicity was analyzed using a cell viability assay. Results In this study we show competitive effects of the 3-pyridinesulfonate, 2-aminoethylhydrogen sulfate, 5-aminovalerate, β-aminobutyrate, piperidine-4-sulfonate, 2-aminoethylphosphate and homotaurine. We demonstrate that taurine uptake can be inhibited by a phosphate. Furthermore our studies revealed that piperidine-4-sulfonate interacts with TauT with a higher affinity than γ-aminobutyrate and imidazole-4-acetate. Conclusion We propose that piperidine-4-sulfonate may serve as a potential lead structure for the design of novel drug candidates required for specific modulation of the TauT transporter in therapy of neurodegenerative diseases.
- Published
- 2019