Geert De Jaeger leads the Functional Interactomics Group. The field of functional interactomics aims to map system-wide molecular interactions and analyze their function. This is of pivotal importance, as biological structures and functions are generally accomplished by networks of short- and long-term molecular interactions. As a technology-driven team, our research focuses on the continuous development and optimization of interactomics tools for plant research, more specifically for the discovery of protein-protein interactions and interactions between proteins and nucleic acids. At the core of our technology lies affinity purification coupled to mass spectrometry (AP-MS). The advantage of this approach is that interactions are mapped in situ, enabling proteome-wide investigation of interactions that occur inside plant cells. We implement these interactomics tools to gain insight on how cell growth and proliferation are regulated in plants, and as such discover new avenues for the engineering of plant growth. Many important signaling pathways impinge on the growth and proliferation of cells in plants. However, signaling pathways involving key growth regulators such as nutrients remain to a large extent elusive in plants. To broaden our knowledge in these nutrient signaling pathways, we are studying protein complexes comprising the antagonistic target of rapamycin (TOR) and SNF1-related (SnRK1) kinases, two master regulators that integrate nutrient signaling with plant growth.