Related Experiment Video
Updated: Mar 19, 2026

Targeting Cysteine Thiols for in Vitro Site-specific Glycosylation of Recombinant Proteins
Published on: October 4, 2017
Golgi self-correction generates bioequivalent glycans to preserve cellular homeostasis
Haik Mkhikian1, Christie-Lynn Mortales1, Raymond W Zhou2
1Department of Microbiology and Molecular Genetics, University of California, Irvine, United States.
Abstract:
Essential biological systems employ self-correcting mechanisms to maintain cellular homeostasis. Mammalian cell function is dynamically regulated by the interaction of cell surface galectins with branched N-glycans. Here we report that N-glycan branching deficiency triggers the Golgi to generate bioequivalent N-glycans that preserve galectin-glycoprotein interactions and cellular homeostasis. Galectins bind N-acetyllactosamine (LacNAc) units within N-glycans initiated from UDP-GlcNAc by the medial-Golgi branching enzymes as well as the trans-Golgi poly-LacNAc extension enzyme β1,3-N-acetylglucosaminyltransferase (B3GNT). Marginally reducing LacNAc content by limiting N-glycans to three branches results in T-cell hyperactivity and autoimmunity; yet further restricting branching does not produce a more hyperactive state. Rather, new poly-LacNAc extension by B3GNT maintains galectin binding and immune homeostasis. Poly-LacNAc extension is triggered by redistribution of unused UDP-GlcNAc from the medial to trans-Golgi via inter-cisternal tubules. These data demonstrate the functional equivalency of structurally dissimilar N-glycans and suggest a self-correcting feature of the Golgi that sustains cellular homeostasis.
Related Concept Videos
Oligosaccharide Assembly
Multiple sugar molecules that may or may...
Protein Folding Quality Check in the RER
Protein Glycosylation
Glycosylation occurs in...
Proteoglycans
Golgi Matrix Proteins
One of the first identified Golgi matrix proteins was GM130, a rod-like protein located in the cis-Golgi. Subsequently, many Golgi...
Golgi Apparatus

