Unravelling the correlation between different ER-based types of glycosylation via glyco/proteo-analytics

• Applicant: Dr. Erdmann Rapp
• Subject Area: Biochemistry
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 289991887

Protein glycosylation, i.e. the covalent attachment of single monosaccharides or complex oligosaccharides to specific amino acids within a peptide sequence, is a co- and post-translational modification conserved across all domains of life (bacteria, archaea, eukaryota). Located on the majority of secreted or membrane-bound proteins, glycans are involved in virtually every cellular event, and essential for vertebrate development and physiology. N-glycosylation, the most common form of glycosylation, is initiated at the endoplasmic reticulum translocon (ER) and requires nucleotide sugars and dolichol-linked precursors (e.g. guanosine diphosphate mannose (GDP-Man) and dolichol monophosphate mannose (Dol-P-Man)) for the early stages of synthesis. Two other ER-resident forms of glycosylation, C-mannosylation and O-mannosylation, also depend on Dol-P-Man for their initial synthesis. Dependencies, compensatory effects, and the competition for the common mannose substrates and acceptor proteins of these three dolichol-based glycosylation pathways are largely unknown, but of high relevance to understand glycosylation-related diseases and disorders, such as infectious and autoimmune diseases, cancer, and congenital disorders of glycosylation (CDG). To unravel their interplay, we intend to study N-glycosylation, C-mannosylation, O-mannosylation in different model systems (cell lines, patient cells, and fish lines), deficient for either of the three pathways, as well as model proteins produced in these systems, e.g. integrin-ß1 derived from POMT2-/- HEK293 cells. To obtain a holistic view on resulting glycosylation alterations, these model systems will be analysed with respect to changes in glycan macro- and microheterogeneity using our comprehensive and state-of-the art glyco/proteo-analytical toolbox.

• DFG Programme: Research Units
• Subproject of: FOR 2509: The concert of dolichol-based glycosylation: from molecules to disease models