Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany.
FAU NeW - Research Center New Bioactive Compounds, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany.
FEBS J. 2024 Nov;291(21):4732-4743. doi: 10.1111/febs.17255. Epub 2024 Aug 29.
Amino acids are important for cellular metabolism. Their uptake across the plasma membrane is mediated by transport proteins. Despite the fact that the organic anion transporting polypeptide 4C1 (OATP4C1, Uniprot: Q6ZQN7) mediates transport of l-arginine and l-arginine derivatives, other members of the OATP family have not been characterized as amino acid transporters. The OATP family member OATP3A1 (gene symbol SLCO3A1, Uniprot: Q9UIG8) is ubiquitously expressed in human cells and highly expressed in many cancer tissues and cell lines. However, only a few substrates are known for OATP3A1. Accordingly, knowledge about its biological relevance is restricted. Our aim was to identify new substrates of OATP3A1 to gain insights into its (patho-)physiological function. In an LC-MS-based untargeted metabolomics assay using untreated OATP3A1-overexpressing HEK293 cells and control cells, we identified several amino acids as potential substrates of OATP3A1. Subsequent uptake experiments using exogenously added substrates revealed OATP3A1-mediated transport of l-tryptophan, l-tyrosine, and l-phenylalanine with 194.8 ± 28.7% (P < 0.05), 226.2 ± 18.7% (P < 0.001), and 235.2 ± 13.5% (P < 0.001), respectively, in OATP3A1-overexpressing cells compared to control cells. Furthermore, kinetic transport parameters (K values) were determined (Trp = 61.5 ± 14.2 μm, Tyr = 220.8 ± 54.5 μm, Phe = 234.7 ± 20.6 μm). In summary, we identified the amino acids l-tryptophan, l-tyrosine, and l-phenylalanine as new substrates of OATP3A1. These findings could be used for a better understanding of (patho-)physiological processes involving increased demand of amino acids, where OATP3A1 should be considered as an important uptake transporter of l-tryptophan, l-tyrosine, and l-phenylalanine.
氨基酸对细胞代谢很重要。它们穿过质膜的摄取是由转运蛋白介导的。尽管有机阴离子转运多肽 4C1（OATP4C1，Uniprot：Q6ZQN7）介导 l-精氨酸和 l-精氨酸衍生物的转运，但 OATP 家族的其他成员尚未被鉴定为氨基酸转运体。OATP 家族成员 OATP3A1（基因符号 SLCO3A1，Uniprot：Q9UIG8）在人细胞中广泛表达，在许多癌症组织和细胞系中高表达。然而，目前仅知道 OATP3A1 的少数底物。因此，对其生物学相关性的了解受到限制。我们的目标是鉴定 OATP3A1 的新底物，以深入了解其（病理）生理功能。在使用未处理的 OATP3A1 过表达 HEK293 细胞和对照细胞的基于 LC-MS 的非靶向代谢组学测定中，我们鉴定出几种氨基酸可能是 OATP3A1 的底物。随后使用外源性添加的底物进行摄取实验，结果表明 OATP3A1 介导了 l-色氨酸、l-酪氨酸和 l-苯丙氨酸的转运，与对照细胞相比，OATP3A1 过表达细胞中的转运分别为 194.8 ± 28.7%（P < 0.05）、226.2 ± 18.7%（P < 0.001）和 235.2 ± 13.5%（P < 0.001）。此外，还确定了动力学转运参数（K 值）（Trp = 61.5 ± 14.2 μm，Tyr = 220.8 ± 54.5 μm，Phe = 234.7 ± 20.6 μm）。总之，我们鉴定出氨基酸 l-色氨酸、l-酪氨酸和 l-苯丙氨酸为 OATP3A1 的新底物。这些发现可用于更好地理解涉及氨基酸需求增加的（病理）生理过程，其中 OATP3A1 应被视为 l-色氨酸、l-酪氨酸和 l-苯丙氨酸的重要摄取转运体。
