Seminar Prof Michael Hothorn

11:00 - 12:30

Jozef Schell seminar room

“Control of plant phosphate homeostasis by inositol pyrophosphate nutrient messengers”

Phosphorus forms an essential structural component of membranes and nucleic acids, represents an important signaling molecule and the energy currency of the cell. It is taken up by plants in the form of inorganic phosphate (Pi). How eukaryotic cells ‘measure’ intracellular Pi levels and respond to changes in Pi availability remains to be uncovered at the mechanistic level. We have previously reported that eukaryotic SPX domains are cellular receptors for Pi-rich inositol pyrophosphate (PP-InsP) nutrient messengers. In Pi sufficient growth conditions, PP-InsP levels are high and enable the binding of the nutrient messenger to its SPX receptor. In plants, the activated receptor can in turn bind a family of phosphate starvation responsive transcription factors rendering them unable to bind DNA. Under phosphate starvation PP-InsP levels drop, the receptor – transcription factor complex dissociates and the released transcription factor can activate Pi-starvation responsive gene expression. I will present our current mechanistic understanding of this nutrient signaling pathway as well as a quantitative biochemical, structural and physiological characterization of PP-InsP biosynthesis and catabolism in the model plants Arabidopsis and Marchantia.

Invited by Prof Yves Van de Peer and Prof Jenny Russinova