ヒグチ　ケイ   Higuchi Kei   樋口　慧    所属   東邦大学  薬学部 薬学科    職種   准教授
論文種別	原著
言語種別	英語
査読の有無	査読あり
表題	Mammalian monocarboxylate transporter 7 (MCT7/Slc16a6) is a novel facilitative taurine transporter.
掲載誌名	正式名：The Journal of biological chemistry
掲載区分	国外
巻・号・頁	298(4),pp.101800-101800
著者・共著者	Kei Higuchi,Koki Sugiyama,Ryuto Tomabechi,Hisanao Kishimoto,Katsuhisa Inoue
担当区分	筆頭著者
発行年月	2022/03/04
概要	Monocarboxylate transporter 7 (MCT7) is an orphan transporter expressed in the liver, brain, and in several types of cancer cells. It has also been reported to be a survival factor in melanoma and breast cancers. However, this survival mechanism is not yet fully understood due to MCT7's unidentified substrate(s). Therefore, here we sought to identify MCT7 substrate(s) and characterize the transport mechanisms by analyzing amino acid transport in HEK293T cells and polarized Caco-2 cells. Analysis of amino acids revealed significant rapid reduction in taurine from cells transfected with EGFP-tagged MCT7. We found that taurine uptake and efflux by MCT7 was pH-independent, and that the uptake was not saturated in the presence of taurine excess of 200 millimolar. Furthermore, we found that monocarboxylates and acidic amino acids inhibited MCT7-mediated taurine uptake. These results imply that MCT7 may be a low-affinity facilitative taurine transporter. We also found that MCT7 was localized at the basolateral membrane in polarized Caco-2 cells, and that the induction of MCT7 expression in polarized Caco-2 cells enhanced taurine permeation. Finally, we demonstrated that interactions of MCT7 with ancillary proteins basigin/CD147 and embigin/GP70 enhanced MCT7-mediated taurine transport. In summary, these findings reveal that taurine is a novel substrate of MCT7 and that MCT7-mediated taurine transport might contribute to the efflux of taurine from cells.
DOI	10.1016/j.jbc.2022.101800
PMID	35257743