Enrichment of Phosphorylated MHC Peptides with Immobilized Metal Affinity Chromatography and Titanium Dioxide Particles
Phosphorylation is one of the most important forms of posttranslational modification. Dysregulation of phosphorylation is implicated in tumorigenesis, with cancerous signaling pathways activated by kinases. For immunotherapy with neoantigen-based peptides, phosphopeptides derived from aberrantly phosphorylated proteins presented by major histocompatibility complex (MHC) are promising candidates due to their specificity to elicit cytotoxic T-cell responses. Unlike other MHC peptides, phosphorylated MHC peptides cannot be predicted from DNA sequences, and their identification relies on the direct detection of phosphopeptides using mass spectrometry (MS). For MS detection, it is extremely important to enrich phosphorylated peptides from the complex repertoire of MHC peptides. Herein, we describe the combined use of immobilized metal affinity chromatography and titanium dioxide nanoparticles for phosphopeptides enrichment from immunopeptidome.
Key wordsImmunotherapy MHC peptides Phosphorylation IMAC LC-MS/MS