Bump-and-Hole Engineering Identifies Specific Substrates of Glycosyltransferases in Living Cells

Mol Cell. 2020 Jun 4;78(5):824-834.e15. doi: 10.1016/j.molcel.2020.03.030. Epub 2020 Apr 22.

Abstract

Studying posttranslational modifications classically relies on experimental strategies that oversimplify the complex biosynthetic machineries of living cells. Protein glycosylation contributes to essential biological processes, but correlating glycan structure, underlying protein, and disease-relevant biosynthetic regulation is currently elusive. Here, we engineer living cells to tag glycans with editable chemical functionalities while providing information on biosynthesis, physiological context, and glycan fine structure. We introduce a non-natural substrate biosynthetic pathway and use engineered glycosyltransferases to incorporate chemically tagged sugars into the cell surface glycome of the living cell. We apply the strategy to a particularly redundant yet disease-relevant human glycosyltransferase family, the polypeptide N-acetylgalactosaminyl transferases. This approach bestows a gain-of-chemical-functionality modification on cells, where the products of individual glycosyltransferases can be selectively characterized or manipulated to understand glycan contribution to major physiological processes.

Keywords: O-glycosylation; bioorthogonal; chemical proteomics; glycosyltransferase; isoenzyme; mucin.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biosynthetic Pathways
  • Cell Membrane / metabolism
  • Glycosylation
  • Glycosyltransferases / chemistry
  • Glycosyltransferases / metabolism*
  • Glycosyltransferases / physiology
  • HEK293 Cells
  • Hep G2 Cells
  • Humans
  • K562 Cells
  • N-Acetylgalactosaminyltransferases / chemistry
  • N-Acetylgalactosaminyltransferases / metabolism
  • N-Acetylgalactosaminyltransferases / physiology
  • Polypeptide N-acetylgalactosaminyltransferase
  • Polysaccharides / chemistry
  • Polysaccharides / metabolism*
  • Protein Engineering / methods*
  • Proteins / metabolism

Substances

  • Polysaccharides
  • Proteins
  • Glycosyltransferases
  • N-Acetylgalactosaminyltransferases