Molecular sensors for nutrients metabolites and messengers: tools for understanding the regulation of the metabolome. Our projects focus on carbon and nitrogen signaling and we use a comparative approach by using three model systems: yeast, Arabidopsis and mammalian cells. We developed new tools to study homeostasis, namely genetically encoded FRET sensors for sugars and amino acids. Complementary to the analysis of the signaling networks is an approach to systematically map membrane protein interactions to identify the underlying physical networks.