Sphingoproteomics: Proteomic strategies to examine sphingolipid biology

Interest in sphingolipids has increased in the past couple of decades as the number of biological activities identified has greatly expanded. These include roles in inflammation, proliferation, survival, and metastasis. Sphingolipids can exert these effects through an increasing number of identified interacting cellular targets. To facilitate the understanding of the intrinsic biology of sphingolipids and the development of sphingolipid-based therapeutics, further knowledge is needed. Various analytical protocols assist this endeavor, with mass spectrometry-based techniques seeing increasing usage, especially for measuring steady-state lipid levels. The area of mass spectrometry-based proteomics is also seeing increased usage in the study of lipid biology. This chapter provides an introduction to hypothesisgenerating and hypothesis-testing protein-based analytical approaches to investigate sphingolipids and sphingolipid-metabolizing enzymes. These tools can serve to identify how sphingolipids regulate the proteome, to define how post- translational modifications control enzymatic activity, to identify protein-protein and protein- lipid interactions as well as to facilitate inhibitor development, among other concepts.