Related Experiment Video
Updated: Jul 11, 2026
11:25
Targeting Cysteine Thiols for in Vitro Site-specific Glycosylation of Recombinant Proteins
Published on: October 4, 2017
Quail Sulf1 function requires asparagine-linked glycosylation
Rashmi K Ambasta1, Xingbin Ai, Charles P Emerson
1Boston Biomedical Research Institute, 64 Grove Street, Watertown, MA 02472, USA.
The Journal of Biological Chemistry
|September 15, 2007
Summary
Heparan sulfate endosulfatases Sulf1 and Sulf2 are crucial for growth factor signaling. N-linked glycosylation of quail Sulf1 (QSulf1) is essential for its activity, heparin binding, and 6-O-desulfation function.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Heparan sulfate endosulfatases Sulf1 and Sulf2 regulate growth factor signaling by modifying heparan sulfate proteoglycans.
- These enzymes control the 6-O-sulfation states of cell-surface and matrix heparan sulfate proteoglycans.
Purpose of the Study:
- To investigate the post-translational modification of quail Sulf1 (QSulf1).
- To determine the role of glycosylation in QSulf1's enzymatic activity, localization, and function.
Main Methods:
- Domain mapping and protein glycosylation prediction to identify glycosylation sites.
- Use of glycosylation inhibitors to assess the impact of modification on QSulf1.
- N-glycanase cleavage of native QSulf1 to directly evaluate the role of N-linked glycosylation.
Main Results:
- QSulf1 was identified as an asparagine-linked glycosylated protein with multiple glycosylation sites in its enzymatic and C-terminal domains.
- Glycosylation is essential for QSulf1's enzymatic activity, membrane targeting, and secretion.
- N-linked glycosylation is specifically required for QSulf1's heparin binding and 6-O-desulfation activity.
Conclusions:
- N-linked glycosylation plays a critical role in controlling the enzymatic function of Sulf1.
- The findings highlight the importance of post-translational modifications in regulating heparan sulfate endosulfatase activity and signaling.
Related Concept Videos
01:20Sulfur Assimilation
Sulfur is an essential element in biological systems, contributing to synthesizing key biomolecules, including amino acids such as cysteine and methionine, and cofactors such as coenzyme A and biotin. Microorganisms primarily assimilate sulfur as sulfate (SO₄²⁻) from the environment, which must undergo a series of biochemical transformations before it can be incorporated into cellular components. As sulfate is highly oxidized, it must undergo assimilatory sulfate reduction to become...
01:29Protein Folding Quality Check in the RER
ER is the primary site for the maturation and folding of soluble and transmembrane secretory proteins. The calnexin cycle is a specific chaperone system that folds and assesses the confirmation of N-glycosylated proteins before they can exit the ER lumen. The primary players of this quality check pipeline are the lectins, ER-resident chaperones, and a glucosyl transferase enzyme. In case the calnexin system in the lumen fails to salvage a misfolded protein, it is transported to the cytoplasm...
01:24Oligosaccharide Assembly
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...
01:25Protein Glycosylation
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...
01:26Protein Modifications in the RER
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 sequences.
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 sequences.
01:19Phase II Reactions: Sulfation and Conjugation with α-Amino Acids
Sulfation and α-amino acid conjugation are two critical biotransformation reactions in drug metabolism. Sulfation, a phase II biotransformation reaction, involves adding a polar sulfate group to a drug, enhancing its water solubility and promoting excretion. This process can either co-occur with or occur independently of glucuronidation. Nonmicrosomal sulfotransferase enzymes catalyze the process. The reaction involves 3'-phosphoadenosine-5'-phosphosulfate or PAPS coenzyme activation, sulfur...