Chemi-enzymatic and data mining approaches for the identification of post-translational modifications

点击翻译按钮获取中文摘要

Post-translational modifications (PTMs) of proteins play an intrinsic role in modulating numerous cellular activities including protein translocation, turnover, and interaction with binding partners. In human cells, the covalent attachment of more than 200 types of PTMs is carried out by dedicated enzymes representing about 5 % of the genome. Several of them including kinases, ubiquitin- and small ubiquitin-like modifier (SUMO) enzymes are misregulated in cancer cells, thus representing putative targets for drug discovery and cancer research programs. The functional correlation of these enzymes with phenotypic changes associated with tumorigenesis requires comprehensive profiling of PTMs at the genomic-scale, a daunting task given their diversity, stoichiometry and low distribution frequency within protein structures and cell extracts. In this context, mass spectrometry (MS) has proven to be an essential analytical tool providing sensitive and specific identification of PTMs from complex cell extracts. Our research program "Chemi-enzymatic and data mining approaches for the identification of PTMs" builds upon recent advances from our group in large-scale quantitative MS-based proteomics to profile protein modifications from affinity-enriched biological extracts. As part of this proposal, we will develop specific enrichment and digestion strategies together with targeted MS detection approaches for the identification of protein phosphorylation and sumoylation; two modifications of significant interest in cell signaling and cancer research. The tools developed will be applied in the study of cancer cell model systems to identify novel substrates and to unravel networks of interacting proteins modulated by chemical stimulants, kinase inhibitors and known chromosomal translocations associated with leukemia. More importantly, analytical tools developed in this proposal will be of broader application to any large-scale proteomics and drug discovery programs investigating protein-drug interactions and cell signaling events for the development of better targeted medicines ultimately improving human health.