Abstract
Core components of the N-glycosylation pathway are known, but the metabolic and post-translational mechanisms regulating this pathway in normal and disease states remain elusive. Using a multi-omic approach in zebrafish, we discovered a mechanism whereby O-GlcNAcylation directly impacts the expression and abundance of two rate-limiting proteins in the N-linked glycosylation pathway. We show in a model of an inherited glycosylation disorder PMM2-CDG, congenital disorders of glycosylation that phosphomannomutase deficiency is associated with increased levels of UDP-GlcNAc and protein O-GlcNAcylation. O-GlcNAc modification increases the transcript and protein abundance of both NgBR and Dpagt1 in pmm2m/m mutants. Modulating O-GlcNAc levels, NgBR abundance, or Dpagt1 activity exacerbated the cartilage phenotypes in pmm2 mutants, suggesting that O-GlcNAc-mediated increases in the N-glycosylation machinery are protective. These findings highlight nucleotide-sugar donors as metabolic sensors that regulate two spatially separated glycosylation pathways, demonstrating how their coordination is relevant to disease severity in the most common congenital disorder of glycosylation.
Keywords:
CDG; CP: Molecular biology; O-GlcNAc; disease modifiers; glycosylation; sugar metabolism; zebrafish.