Photoproximity Labeling of Sialylated Glycoproteins (GlycoMap) Reveals Sialylation-Dependent Regulation of Ion Transport

Claudio F. Meyer, Ciaran P. Seath, Steve D. Knutson, Wenyun Lu, Joshua D. Rabinowitz, David W.C. Macmillan

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Sialylation, the addition of sialic acid to glycans, is a crucial post-translational modification of proteins, contributing to neurodevelopment, oncogenesis, and immune response. In cancer, sialylation is dramatically upregulated. Yet, the functional biochemical consequences of sialylation remain mysterious. Here, we establish a μMap proximity labeling platform that utilizes metabolically inserted azidosialic acid to introduce iridium-based photocatalysts on sialylated cell-surface glycoproteins as a means to profile local microenvironments across the sialylated proteome. In comparative experiments between primary cervical cells and a cancerous cell line (HeLa), we identify key differences in both the global sialome and proximal proteins, including solute carrier proteins that regulate metabolite and ion transport. In particular, we show that cell-surface interactions between receptors trafficking ethanolamine and zinc are sialylation-dependent and impact intracellular metabolite levels. These results establish a μMap method for interrogating proteoglycan function and support a role for sialylated glycoproteins in regulating cell-surface transporters.

Original languageEnglish (US)
Pages (from-to)23633-23641
Number of pages9
JournalJournal of the American Chemical Society
Issue number51
StatePublished - Dec 28 2022

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Biochemistry
  • Catalysis
  • Colloid and Surface Chemistry


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