Saldanha S Adrian, Grimm Christian, Allais Christophe, Smith Emery, Ouizem Souad, Mercer Becky A., Roush William R., Heller Stefan, Hodder Peter
Lead Identification Division, Translational Research Institute, Scripps Florida, 130 Scripps Way, Jupiter, FL 33458
Departments of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305.
When mutated, the Transient Receptor Potential Channels 3 (TRPML3) ion channel causes deafness and pigmentation defects. Due to the lack of available compounds known to act as selective TRPML3 agonists, the identification of selective probes for TRPML3 are useful to investigate the function of TRPML3 in inner ear mechanotransduction and hearing biology. The two probes reported here, CID 776924 (ML268) and CID 53239838 (ML269), emerged from an HTS-based effort to identify small molecule activators of TRPML3. They exhibit submicromolar EC values against TRPML3 in intracellular calcium functional assays. Further, their selectivity & mechanism-of-action has been confirmed in various in patch clamp and functional assays. Interestingly, testing these probes and other TRPML3 activators on TRPML3-expressing sensory hair cells revealed the absence of activator-responsive channels. Similarly, epidermal melanocytes showed only weak or no responses when exposed to the compounds. These studies validate the biological relevance of these probes, as they have now been used to demonstrate that TRPML3 might be absent from the plasma membrane or that the protein is a subunit of heteromeric channels in native cells A comprehensive summary of their activity has been published [1]. ML268 and ML269 are first-in-class tools for elucidating the functions of the TRPML3 ion channel. The significance of their impact was the subject of a special review article [2].
瞬时受体电位通道3（TRPML3）离子通道发生突变时会导致耳聋和色素沉着缺陷。由于缺乏已知可作为选择性TRPML3激动剂的化合物，鉴定TRPML3的选择性探针对于研究TRPML3在内耳机械转导和听力生物学中的功能很有用。本文报道的两种探针，CID 776924（ML268）和CID 53239838（ML269），是基于高通量筛选（HTS）来鉴定TRPML3小分子激活剂的工作中发现的。在细胞内钙功能测定中，它们对TRPML3表现出亚微摩尔的EC值。此外，它们的选择性和作用机制已在各种膜片钳和功能测定中得到证实。有趣的是，在表达TRPML3的感觉毛细胞上测试这些探针和其他TRPML3激活剂时，发现没有激活剂响应通道。同样，表皮黑素细胞在接触这些化合物时仅表现出微弱或无反应。这些研究证实了这些探针的生物学相关性，因为它们现在已被用于证明TRPML3可能不存在于质膜上，或者该蛋白是天然细胞中异源通道的一个亚基。它们活性的全面总结已发表[1]。ML268和ML269是阐明TRPML3离子通道功能的一流工具。它们影响的重要性是一篇特别综述文章的主题[2]。
