Thursday, November 21, 2024
11/21/2024
Summary: Mass spectrometry (MS) has proven invaluable in studying the mechanisms of cellular signaling as MS platforms can directly provide amino acid residue site-specific phosphorylation data compared to traditional antibody-based approaches. However, limitations exist in current MS approaches in generating confident site-specific phosphorylation quantification. This is particularly evident in complex multi-phosphorylated protein motifs, where the detection of isomeric multi-phosphorylated peptides easily overwhelms any prediction scoring approach that is simply based upon the fragmentation spectra. There are many biological examples of hyperphosphorylated regions, where they are associated with receptor/ligand interactions, including G-protein coupled receptors (GPCRs), membrane receptors that are the most common targets for FDA-approved drugs. For accurate site-specific quantification of protein hyperphosphorylation we propose a transdisciplinary approach using ultrahigh resolution Ion Mobility Separation (IMS) integrated with highly accurate and sensitive MS and MS/MS spectra to enable the confident characterization of hyperphosphorylated GPCR ensembles with greatly improved sensitivity, and speed. We will use multi-level Structures for Lossless Ion Manipulations (SLIM) technology (SLIM-Orbitrap platform) to fully characterize phosphorylation of GPCR/antagonist interactions utilizing CXCR3, which plays a central role in inflammatory diseases through its regulation of T cell function as an initial test case. We plan to first integrate ultrahigh resolution IMS with an advanced Orbitrap MS platform for unambiguous decoding of hyperphosphorylated sites, evaluate the SLIM-Orbitrap MS platform for resolving hyperphosphorylated protein regions, and finally, perform comprehensive site-specific phosphoproteomics for GPCRs through screening of activated T cells with dose-responses of chemokine and small-molecule CXCR3 biased agonists.
HHS’ Tracking Accountability in Government Grants System (TAGGS) website provides access to detailed descriptions of grants, loans, aggregated direct payments and other types of financial assistance awarded by the HHS Operating Divisions (OPDIVs) and the Office of the Secretary Staff Divisions (STAFFDIVs).
