"Sphingolipids are major components of the human cell and are involved in human pathologies ranging from lysosomal storage disorders to type 2 diabetes. Here, we propose to establish an integrated research program for the study of sphingolipid metabolism, in health and disease. We will combine state-of-the-art synthetic organic chemistry, bioorganic chemistry, analytical chemistry, molecular biology and biochemistry techniques and concepts and apply these in an integrated chemical biology approach to study and manipulate sphingolipid metabolism in vivo and in vitro, using human cells and animal models. The program is subdivided in three individual research lines that are interconnected both in terms of technology development and in their biological context. 1) We will develop modified sphinganine derivatives and apply these to study sphingolipid homeostasis in cells derived from healthy and diseased (Gaucher, Fabry, Niemann-Pick A/B disease) individuals/animal models. This question will be addressed in a chemical metabolomics/lipidomics approach. 2) We will develop activity-based probes aimed at monitoring enzyme activity levels of glycosidases involved in (glyco)sphingolipid metabolism, in particular the enzymes that - when mutated and thereby reduced in activity- are responsible for the lysosomal storage disorders Gaucher disease and Fabry disease. 3) We will develop well-defined enzymes and chaperone proteins for directed correction of sphingolipid homeostasis in Gaucher, Fabry and Niemann-Pick A/B patients, via a newly designed semi-synthetic approach that combines sortase-mediated ligation with synthetic chemistry. Deliverables are a better understanding of the composition of the sphingolipid pool that are at the basis of lysosomal storage disorders, effective ways to in situ monitor the efficacy of therapies (enzyme inhibitors, chemical chaperones, recombinant enzymes) to treat these and improved semi-synthetic proteins for enzyme replacement therapy."