PDF(Pubmed)
Abstract：
The peptide/histidine transporter PHT1 (SLC15A4) is expressed in the lysosomal membranes of immune cells where it plays an important role in metabolic and inflammatory signaling. PHT1 is an H+-coupled/histidine symporter that can transport a wide range of oligopeptides, including a variety of bacterial-derived peptides. Moreover, it enables the scaffolding of various metabolic signaling molecules and interacts with key regulatory elements of the immune response. Not surprisingly, PHT1 has been implicated in the pathogenesis of autoimmune diseases such as systemic lupus erythematosus (SLE). Unfortunately, the pharmacological development of PHT1 modulators has been hampered by the lack of suitable transport assays. To address this shortcoming, a novel transport assay based on solid-supported membrane-based electrophysiology (SSME) is presented. Key findings of the present SSME studies include the first recordings of electrophysiological properties, a pH dependence analysis, an assessment of PHT1 substrate selectivity, as well as the transport kinetics of the identified substrates. In contrast to previous work, PHT1 is studied in its native lysosomal environment. Moreover, observed substrate selectivity is validated by molecular docking. Overall, this new SSME-based assay is expected to contribute to unlocking the pharmacological potential of PHT1 and to deepen the understanding of its functional properties.
摘要：
肽/组氨酸转运蛋白PHT1（SLC15A4）在免疫细胞的溶酶体膜中表达，在代谢和炎症信号传导中起重要作用。PHT1是一个H+偶联/组氨酸转运体，可以转运多种寡肽，包括各种细菌衍生的肽。此外，它使各种代谢信号分子的支架，并与免疫反应的关键调节元件相互作用。毫不奇怪,PHT1与自身免疫性疾病如系统性红斑狼疮（SLE）的发病机理有关。不幸的是,PHT1调节剂的药理学开发由于缺乏合适的转运试验而受到阻碍。为了解决这个缺点，提出了一种基于固体支持膜的电生理学（SSME）的新型转运测定法。目前SSME研究的主要发现包括电生理特性的首次记录，pH依赖性分析，对PHT1底物选择性的评估，以及所识别底物的传输动力学。与以前的工作相比，PHT1在其天然溶酶体环境中进行研究。此外，通过分子对接验证了观察到的底物选择性。总的来说,这种新的基于SSME的检测方法有望有助于释放PHT1的药理学潜力，并加深对其功能特性的理解。
