Structural basis for phosphorylation-induced inactivation of the rice ammonium transporter AMT1;1
- 1CAS Center for Excellence in Molecular Plant Sciences
Abstract
Ammonium (NH4+) uptake and transport in plants are mediated by ammonium transporters (AMTs), which are tightly regulated by phosphorylation to prevent excess ammonium influx and toxic accumulation. However, the mechanism of phosphorylation-mediated inactivation is unique and remains unclear. Here, we report cryo-EM structures of the rice (Oryza sativa) ammonium transporter OsAMT1;1 in its wild-type and phosphomimetic variant T452D states. OsAMT1;1 forms a stable homotrimer, with conserved motifs affirming a shared transport mechanism within the AMT/MEP/Rh superfamily. Our structural analysis reveals that T452D phosphomimetic stabilizes an intracellular salt-bridge network and maintains the channel in a closed state, in which the ICL5 loop positions the hydrophobic plug residue Leu360 near the cytoplasmic exit to occlude the channel exit and abolish complementation capacity. Our findings elucidate phosphorylation-induced inactivation mechanism for the plant AMT1 subfamily, providing a structural paradigm for the post-translational regulation of nutrient uptake.
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BibTeX
@misc{yu2026structural,
title = {{Structural basis for phosphorylation-induced inactivation of the rice ammonium transporter AMT1;1}},
author = {F. Yu and X. Huang and S. Wang and N. An and P. Zhang and J. Huang and X. Zhang},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.12.758405},
url = {https://www.biorxiv.org/content/10.64898/2026.10.12.758405v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Structural basis for phosphorylation-induced inactivation of the rice ammonium transporter AMT1;1
AU - F. Yu
AU - X. Huang
AU - S. Wang
AU - N. An
AU - P. Zhang
AU - J. Huang
AU - X. Zhang
PY - 2026
DA - 2026/10/12
PB - bioRxiv
DO - 10.64898/2026.10.12.758405
UR - https://www.biorxiv.org/content/10.64898/2026.10.12.758405v1
AB - Ammonium (NH4+) uptake and transport in plants are mediated by ammonium transporters (AMTs), which are tightly regulated by phosphorylation to prevent excess ammonium influx and toxic accumulation. However, the mechanism of phosphorylation-mediated inactivation is unique and remains unclear. Here, we report cryo-EM structures of the rice (Oryza sativa) ammonium transporter OsAMT1;1 in its wild-type and phosphomimetic variant T452D states. OsAMT1;1 forms a stable homotrimer, with conserved motifs affirming a shared transport mechanism within the AMT/MEP/Rh superfamily. Our structural analysis reveals that T452D phosphomimetic stabilizes an intracellular salt-bridge network and maintains the channel in a closed state, in which the ICL5 loop positions the hydrophobic plug residue Leu360 near the cytoplasmic exit to occlude the channel exit and abolish complementation capacity. Our findings elucidate phosphorylation-induced inactivation mechanism for the plant AMT1 subfamily, providing a structural paradigm for the post-translational regulation of nutrient uptake.
ER -