Back

Structural basis of stepwise G protein activation by a viral chemokine receptor

Jude, K. M.; Suomivuori, C.-M.; Waghray, D.; Maeda, S.; Fujiyoshi, Y.; Inoue, A.; Garcia, K. C.; Tsutsumi, N.

2025-12-10 biophysics
10.64898/2025.12.10.692789 bioRxiv
Show abstract

G protein-coupled receptors (GPCRs) govern diverse cellular responses and are crucial drug targets. However, the sequence of structural events from G protein recognition to GDP release has remained elusive. Here, we leveraged the viral chemokine GPCR US28 to capture transient activation states of the US28-Gq complex. Using cryo-electron microscopy and an engineered chemokine superagonist, we determined three distinct complex structures, capturing the initial GDP-bound TL-state, the nucleotide-free C-state, and a previously unobserved intermediate bridging the two states, the T2C-state. These structures, along with simulations and functional data, provide high-resolution snapshots of the G protein activation trajectory and reveal a stepwise conformational mechanism that orchestrates G protein activation. This activation cascade closely parallels mechanisms proposed for human GPCRs, suggesting a conserved GPCR signaling mechanism.

Matching journals

The top 3 journals account for 50% of the predicted probability mass.

50% of probability mass above

"Similar papers" are the closest papers from that journal in the model's embedding space. They show what the match is built on, but the ranking comes mostly from a classifier over the whole training set, not from these examples alone.