Human UDP-galactose 4'-epimerase (GALE) is required for cell-surface glycome structure and function.

Journal Article (Journal Article)

Glycan biosynthesis relies on nucleotide sugars (NSs), abundant metabolites that serve as monosaccharide donors for glycosyltransferases. In vivo, signal-dependent fluctuations in NS levels are required to maintain normal cell physiology and are dysregulated in disease. However, how mammalian cells regulate NS levels and pathway flux remains largely uncharacterized. To address this knowledge gap, here we examined UDP-galactose 4'-epimerase (GALE), which interconverts two pairs of essential NSs. Using immunoblotting, flow cytometry, and LC-MS-based glycolipid and glycan profiling, we found that CRISPR/Cas9-mediated GALE deletion in human cells triggers major imbalances in NSs and dramatic changes in glycolipids and glycoproteins, including a subset of integrins and the cell-surface death receptor FS-7-associated surface antigen. In particular, we observed substantial decreases in total sialic acid, galactose, and GalNAc levels in glycans. These changes also directly impacted cell signaling, as GALE -/- cells exhibited FS-7-associated surface antigen ligand-induced apoptosis. Our results reveal a role of GALE-mediated NS regulation in death receptor signaling and may have implications for the molecular etiology of illnesses characterized by NS imbalances, including galactosemia and metabolic syndrome.

Full Text

Duke Authors

Cited Authors

  • Broussard, A; Florwick, A; Desbiens, C; Nischan, N; Robertson, C; Guan, Z; Kohler, JJ; Wells, L; Boyce, M

Published Date

  • January 31, 2020

Published In

Volume / Issue

  • 295 / 5

Start / End Page

  • 1225 - 1239

PubMed ID

  • 31819007

Pubmed Central ID

  • PMC6996900

Electronic International Standard Serial Number (EISSN)

  • 1083-351X

Digital Object Identifier (DOI)

  • 10.1074/jbc.RA119.009271


  • eng

Conference Location

  • United States