Integrated proteomic analysis of post-translational modifications by serial enrichment

A mass spectrometry–based method using serial enrichments of different post-translational modifications (SEPTM) enables high-coverage proteomic analysis of multiple PTMs from a single biological sample. We report a mass spectrometry–based method for the integrated analysis of protein expression, phosphorylation, ubiquitination and acetylation by serial enrichments of different post-translational modifications (SEPTM) from the same biological sample. This technology enabled quantitative analysis of nearly 8,000 proteins and more than 20,000 phosphorylation, 15,000 ubiquitination and 3,000 acetylation sites per experiment, generating a holistic view of cellular signal transduction pathways as exemplified by analysis of bortezomib-treated human leukemia cells.