Download MendeleyStructural mechanisms of human sodium-coupled high-affinity choline transporter CHT1.
Xue, J., Chen, H., Wang, Y., Jiang, Y.(2024) Cell Discov 10: 116-116
- PubMed: 39587078
- DOI: https://doi.org/10.1038/s41421-024-00731-7
- Primary Citation of Related Structures:
9BFI, 9BFJ, 9BFK, 9BIM - PubMed Abstract:
Mammalian sodium-coupled high-affinity choline transporter CHT1 uptakes choline in cholinergic neurons for acetylcholine synthesis and plays a critical role in cholinergic neurotransmission. Here, we present the high-resolution cryo-EM structures of human CHT1 in apo, substrate- and ion-bound, hemicholinium-3-inhibited, and ML352-inhibited states. These structures represent three distinct conformational states, elucidating the structural basis of the CHT1-mediated choline uptake mechanism. Three ion-binding sites, two for Na + and one for Cl - , are unambiguously defined in the structures, demonstrating that both ions are indispensable cofactors for high-affinity choline-binding and are likely transported together with the substrate in a 2:1:1 stoichiometry. The two inhibitor-bound CHT1 structures reveal two distinct inhibitory mechanisms and provide a potential structural platform for designing therapeutic drugs to manipulate cholinergic neuron activity. Combined with the functional analysis, this study provides a comprehensive view of the structural mechanisms underlying substrate specificity, substrate/ion co-transport, and drug inhibition of a physiologically important symporter.
Organizational Affiliation:
Institute of Aging & Tissue Regeneration, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. jxue@shsmu.edu.cn.
