Download MendeleyStructural basis of G6P/Pi transport and inhibition in SLC37A4.
Zhou, D., Zhang, Y., Chen, N., Huang, S., Song, C., Zhang, Z.(2025) Nat Struct Mol Biol
- PubMed: 41225049
- DOI: https://doi.org/10.1038/s41594-025-01711-5
- Primary Citation of Related Structures:
9W1N, 9W1O, 9W1P, 9W1Q, 9W1R - PubMed Abstract:
Glycogen storage disease type Ib (GSD-Ib), caused by loss-of-function mutations in the endoplasmic reticulum transporter SLC37A4, disrupts glucose homeostasis through impaired glucose-6-phosphate (G6P)/phosphate (Pi) antiport. Despite its central role in glycogen metabolism and immune regulation, the structural mechanisms governing SLC37A4's transport cycle and pathological dysfunction remain elusive. Here we report cryo-electron microscopy structures of human SLC37A4 in four functional states, capturing conformational transitions between lumen-facing and cytoplasm-facing states. Combined with mutational analysis, molecular dynamics simulations and functional assays, we identify a conserved substrate-binding pocket that alternately accommodates G6P and Pi through electrostatic complementarity and domain-dependent interactions. We further demonstrate that the high-affinity inhibitor S-4048 sterically occludes the cytoplasmic entry pathway by trapping the transporter in a cytoplasm-facing conformation. Our work elucidates the molecular pathology of GSD-Ib-linked mutations and provides a structural framework for developing therapies targeting this transporter in metabolic diseases.
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China.
Organizational Affiliation:
