Im Dohyun, Jormakka Mika, Juge Narinobu, Kishikawa Jun-Ichi, Kato Takayuki, Sugita Yukihiko, Noda Takeshi, Uemura Tomoko, Shiimura Yuki, Miyaji Takaaki, Asada Hidetsugu, Iwata So
Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Department of Genomics and Proteomics, Advanced Science Research Center, Okayama University, Okayama, Japan.
Nat Commun. 2024 Sep 16;15(1):7661. doi: 10.1038/s41467-024-51960-z.
Human vesicular monoamine transporter 2 (VMAT2), a member of the SLC18 family, plays a crucial role in regulating neurotransmitters in the brain by facilitating their uptake and storage within vesicles, preparing them for exocytotic release. Because of its central role in neurotransmitter signalling and neuroprotection, VMAT2 is a target for neurodegenerative diseases and movement disorders, with its inhibitor being used as therapeutics. Despite the importance of VMAT2 in pharmacophysiology, the molecular basis of VMAT2-mediated neurotransmitter transport and its inhibition remains unclear. Here we show the cryo-electron microscopy structure of VMAT2 in the substrate-free state, in complex with the neurotransmitter dopamine, and in complex with the inhibitor tetrabenazine. In addition to these structural determinations, monoamine uptake assays, mutational studies, and pKa value predictions were performed to characterize the dynamic changes in VMAT2 structure. These results provide a structural basis for understanding VMAT2-mediated vesicular transport of neurotransmitters and a platform for modulation of current inhibitor design.
人类囊泡单胺转运体2（VMAT2）是SLC18家族的一员，通过促进神经递质摄取并储存在囊泡中，为胞吐释放做准备，从而在调节大脑神经递质方面发挥关键作用。由于其在神经递质信号传导和神经保护中的核心作用，VMAT2是神经退行性疾病和运动障碍的治疗靶点，其抑制剂被用作治疗药物。尽管VMAT2在药物生理学中很重要，但其介导的神经递质转运及其抑制作用的分子基础仍不清楚。在此，我们展示了处于无底物状态、与神经递质多巴胺结合以及与抑制剂丁苯那嗪结合的VMAT2的冷冻电镜结构。除了这些结构测定外，还进行了单胺摄取试验、突变研究和pKa值预测，以表征VMAT2结构的动态变化。这些结果为理解VMAT2介导的神经递质囊泡转运提供了结构基础，并为当前抑制剂设计的优化提供了平台。
