Complex dynamics and regulation of the plant energy sensor SnRK1

The plant SnRK1 (SNF-related kinase1) kinases are highly conserved cellular fuel gauges In energy-depleting stress conditions, they stimulate catabolic reactions while repressing energy-consuming anabolic processes, shifting the balance from growth to survival Consistent with their unique lifestyle, plants also have evolved specific regulatory mechanisms Rather than being activated upon energy deficit, SnRK1 is repressed under conditions of energy abundance, in line with the reported inhibition of SnRK1 activity by trehalose-6-phosphate (T6P) SnRK1 functions as a heterotrimeric complex, with a catalytic α subunit and regulatory β and γ subunits Low energy stress triggers nuclear translocation of the α subunit to induce gene expression, but the membrane-associated β subunits remain cytoplasmic A better understanding of the dynamic SnRK1 complex composition and regulation is key to optimize the plant growth/defense balance and develop high yield and stress resilient crops In this project, we will map the SnRK1 interactome together with its post-translational modifications and temporal, spatial and structural dynamics in relation to energy availability In addition, we will specifically explore the exact role and relevance of the strong interactions observed with (1) the class II T6P synthase (TPS) proteins, which may mediate the T6P regulation, and (2) a novel family of SnRK1-interacting negative regulator (SKIN) proteins, apparently controlling SnRK1 localisation