To understand the underlying causes for these pathophysiological states, we need better insight into how animal body responds to changes in nutrient availability. This is the focus of our research group. We study how cellular signaling pathways and gene regulatory networks respond to specific nutrients, such as sugars or amino acids, and how these responses further control growth, energy metabolism and stem cell functions. Such regulatory mechanisms are collectively known as nutrient sensing. Nutrient sensing of multicellular animals is very complex. It involves cell type-specific responses in functionally different tissues and communication between different cell types through hormonal signals. Some of the nutrient sensing mechanisms have been heavily studied and are known in great detail, while others remain to be discovered. We want to uncover these unknown mechanisms, understand their molecular underpinnings, and identify their physiological roles. This new insight will be further used in exploring the mechanisms that underlie human disease. In order to achieve these goals, we need powerful research tools. The main model organism in our laboratory is the fruit fly Drosophila melanogaster, which offers a superior genetic toolkit for detailed cell type-specific analysis and allows efficient genetic screening. Drosophila is compatible with advanced downstream analyses by genomics, metabolomics, and imaging, which are essential for our work.