February 3, 2014
Newly detected enzymes influence signaling lipids in eukaryotic cells
IST Austria Professor Jiři Friml and PhD student Petra Nováková identify group of enzymes involved in the metabolization of messenger substances in the membrane surrounding plant central vacuole
Polyphosphoinositides (PPIs) are signaling lipids in the membrane of eukaryotes, which play an important role in a variety of processes in the cell, from membrane trafficking, cytoskeleton organization, nuclear signaling to stress responses. In their work published on February 3 in PNAS (Doi: 10.1073/pnas.1324264111), IST Austria Professor Jiři Friml and PhD student Petra Nováková, together with colleagues at Ghent University, University of Amsterdam, and the Martin Luther University Halle-Wittenberg, identified a previously functionally uncharacterized group of enzymes, SAC2-SAC5, and show that they modify the levels of PPIs in their plant model, Arabidopsis thaliana. Their results suggest that SAC2-SAC5 are involved in the metabolization of PPIs in the tonoplast, the membrane surrounding a plant cell’s central vacuole. Both loss and overexpression of these enzymes leads to plant growth defects indicating disruptions in vacuole function. Analyzing the effects of gain- and loss-of-function of SAC2-SAC5 and PPIs on the cell, the researchers demonstrate that SAC2-SAC5 and PPIs play important roles in the morphology and function of plant vacuoles.