A pseudoenzyme sensor of trehalose-6-phosphate directly represses the metabolic integrator SnRK1 in plants.

T6P sensor TPS-II directly interacts with SnRK1 to repress its activity in Arabidopsis, revealing a key sugar signaling mechanism conserved across plants.

• Why it matters: Understanding how plants sense and respond to sugar levels is crucial for improving crop productivity and stress resilience, yet the molecular mechanisms remain unclear.
• What they did: Researchers used chemical biology and functional approaches to identify the noncatalytic pseudoenzyme TPS-II as a T6P sensor, demonstrating its conformational change upon T6P binding that enables interaction with SnRK1.
• The result: Loss of TPS-II activates stress responses and suppresses growth-related genes, indicating that the T6P-TPS-II-SnRK1 axis is fundamental for coupling carbon availability to metabolic homeostasis in plants.