Related Experiment Video
Updated: Apr 24, 2026
11:25
Targeting Cysteine Thiols for in Vitro Site-specific Glycosylation of Recombinant Proteins
Published on: October 4, 2017
6.0K
Differential site accessibility mechanistically explains subcellular-specific N-glycosylation determinants
Ling Yen Lee1, Chi-Hung Lin1, Susan Fanayan1
1Department of Chemistry and Biomolecular Sciences, Biomolecular Frontiers Research Centre, Macquarie University , Sydney, NSW , Australia.
Frontiers in Immunology
|September 10, 2014
Summary
Human cells create distinct N-glycosylation patterns on proteins in different locations, using shared cellular machinery. This glycosylation specificity is crucial for protein function in immunity and cellular processes.
Area of Science:
- Glycobiology
- Cellular Biology
- Immunology
Background:
- Glycoproteins mediate immune functions via lectin interactions with glyco-determinants.
- Understanding subcellular N-glycosylation is key to deciphering protein function and cellular processes.
Purpose of the Study:
- To mechanistically explain the formation of subcellular-specific N-glycosylation determinants in human cells.
- To analyze glycan processing differences across subcellular compartments.
Main Methods:
- Liquid chromatography-tandem mass spectrometry (LC-MS/MS) based quantitative glycomics.
- Subcellular glycome and proteomics profiling.
- Gene ontology analysis.
Main Results:
- Secreted glycoproteins exhibit more processed N-glycans (complex type) than microsomal glycoproteins (high-mannose).
- Secreted glycoproteins show increased α-sialylation and α1,6-fucosylation, with reduced α-mannosylation compared to cell-surface and microsomal fractions.
- Glycosylation site accessibility on mature proteins correlates with glycan processing, explaining subcellular specificity.
Conclusions:
- Human cells reproducibly generate subcellular-specific N-glycosylation using shared biosynthetic pathways.
- This site-specific glycosylation is vital for structural and functional glycobiology, impacting lectin interactions in immunity and infection.
Related Concept Videos
01:24Oligosaccharide Assembly
2.6K
Protein glycosylation starts in the ER lumen and continues in the Golgi apparatus. Glycosyltransferases catalyze the addition of sugar molecules or glycosylation of proteins. Usually, these enzymes add sugars to the hydroxyl groups of selected serine or threonine residues to form O-linked glycans or the amino groups of asparagine residues to form N-linked glycans. Different positions on the same polypeptide chain can contain differently linked glycans.
Multiple sugar molecules that may or may...
Multiple sugar molecules that may or may...
2.6K
01:25Protein Glycosylation
8.3K
Glycosylation, the most common post-translational modification for proteins, serves diverse functions. Adding sugars to proteins makes the proteins more resistant to proteolytic digestion. Glycosylated proteins can act as markers and receptors to promote cell-cell adhesion. Additionally, they have many essential quality control functions in the cell, such as correct protein folding and facilitating transport of misfolded proteins to the cytosol, which can be degraded.
Glycosylation occurs in...
Glycosylation occurs in...
8.3K
00:49Ligand Binding and Linkage
4.4K
Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked. In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence...
4.4K
01:05Proteoglycans
4.0K
Glycans, a class of complex heterogeneous molecules, can be covalently attached to proteins to form glycosylated proteins that regulate various physiological and pathological processes. Glycosylated proteins or glycoproteins comprise N-linked and O-linked oligosaccharides. O-glycosylation is the most common type of protein glycosylation. Here, glycans attach to the oxygen atom of the hydroxyl groups of Serine or Threonine residues. O-linked glycosylation occurs later in protein processing,...
4.0K
01:19Allosteric Proteins-ATCase
4.8K
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis...
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis...
4.8K
01:26Protein Modifications in the RER
5.6K
Modification of secretory and transmembrane proteins entering the rough ER begins in the ER lumen. These modifications aid in protein folding and stabilize the acquired tertiary structure. Protein modifications in the rough ER co-occur at different stages of protein folding.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal...
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal...
5.6K