GO:0015018 galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0015018 describes the catalytic activity of beta1,3-glucuronosyltransferase I (GlcAT-I), which transfers glucuronic acid from UDP-alpha-D-glucuronate onto the galactosylgalactosylxylosylprotein acceptor during glycosaminoglycan-protein linkage region biosynthesis.
• This activity is the committing step for chondroitin sulfate, dermatan sulfate, and heparan sulfate proteoglycan synthesis, making it a key regulator of extracellular matrix and cell-surface proteoglycan assembly.
• The enzyme is a type II membrane protein that forms homodimers, and two conserved cysteine residues are essential for dimerization and catalytic function.
• GlcAT-I expression and activity are regulated by calcium-TonEBP signaling, and its substrates are modulated by phosphorylation and sulfation of the linkage oligosaccharide.
• The same enzymatic activity contributes to HNK-1 carbohydrate biosynthesis, which is critical for neural development, synaptic plasticity, and nervous system function.
• Dysregulation of this activity has been linked to intervertebral disc degeneration, neural disorders, and cancer-associated proteoglycan remodeling, making it a target for functional genomics and therapeutic research.
Description
GO:0015018, galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity, is a molecular function that catalyzes the transfer of glucuronic acid from UDP-alpha-D-glucuronate to the trisaccharide acceptor 3-O-(beta-D-galactosyl-(1->3)-beta-D-galactosyl-(1->4)-beta-D-xylosyl)-L-seryl-[protein], yielding a tetrasaccharide linkage region and UDP. This reaction is performed by beta1,3-glucuronosyltransferase I (GlcAT-I), an enzyme that plays a central role in the biosynthesis of the glycosaminoglycan-protein linkage region of proteoglycans. Proteoglycans are essential components of the extracellular matrix and cell surface, where they regulate cell adhesion, migration, signaling, and tissue homeostasis. Because the glucuronosyltransferase step commits the linkage region to maturation into chondroitin sulfate, dermatan sulfate, or heparan sulfate chains, GO:0015018 is a critical control point in proteoglycan biosynthesis. Researchers studying extracellular matrix biology, neurobiology, and musculoskeletal disease therefore need robust tools to interrogate this activity and its regulatory network.
galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity At A Glance
| GO ID | GO:0015018 |
|---|---|
| GO term | galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity |
| Ontology | molecular_function |
| Synonym | glucuronosyltransferase I activity; UDP-glucuronate:3-beta-D-galactosyl-4-beta-D-galactosyl-O-beta-D-xylosyl-protein D-glucuronosyltransferase activity; uridine diphosphate glucuronic acid:acceptor glucuronosyltransferase activity |
| Major function | Transfer of glucuronic acid from UDP-alpha-D-glucuronate to the galactosylgalactosylxylosylprotein acceptor during glycosaminoglycan-protein linkage region biosynthesis |
| Enzyme | Beta1,3-glucuronosyltransferase I (GlcAT-I), encoded by B3GAT3 in humans |
| Substrate donor | UDP-alpha-D-glucuronate |
| Substrate acceptor | 3-O-(beta-D-galactosyl-(1->3)-beta-D-galactosyl-(1->4)-beta-D-xylosyl)-L-seryl-[protein] |
| Product | 3-O-(beta-D-GlcA-(1->3)-beta-D-Gal-(1->3)-beta-D-Gal-(1->4)-beta-D-Xyl)-L-seryl-[protein] + H+ + UDP |
| Pathway context | Glycosaminoglycan-protein linkage region biosynthesis; chondroitin sulfate, dermatan sulfate, and heparan sulfate proteoglycan synthesis |
What Is GO:0015018?
GO:0015018 is defined as the catalysis of the reaction: 3-O-(beta-D-galactosyl-(1->3)-beta-D-galactosyl-(1->4)-beta-D-xylosyl)-L-seryl-[protein] + UDP-alpha-D-glucuronate = 3-O-(beta-D-GlcA-(1->3)-beta-D-Gal-(1->3)-beta-D-Gal-(1->4)-beta-D-Xyl)-L-seryl-[protein] + H+ + UDP. In simpler terms, it is the enzymatic addition of a glucuronic acid residue to a specific galactose-containing trisaccharide attached to a protein serine residue, using UDP-glucuronic acid as the donor substrate. This activity is also known as glucuronosyltransferase I activity or UDP-glucuronate:3-beta-D-galactosyl-4-beta-D-galactosyl-O-beta-D-xylosyl-protein D-glucuronosyltransferase activity.
Why Is galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity Important in Cell Biology?
GO:0015018 is important because it represents the first committed step in the assembly of the glycosaminoglycan-protein linkage region, a structure that anchors chondroitin sulfate, dermatan sulfate, and heparan sulfate chains to core proteins. Without this glucuronosyltransferase activity, proteoglycans cannot acquire their mature glycosaminoglycan chains, which are required for extracellular matrix organization, growth factor sequestration, cell adhesion, and receptor signaling. The enzyme GlcAT-I is also involved in the biosynthesis of the HNK-1 carbohydrate epitope, a sulfated glucuronic acid-containing glycan that regulates neural cell adhesion and synaptic plasticity. Consequently, alterations in this activity have been associated with intervertebral disc degeneration, neural dysfunction, and cancer progression, making it a compelling target for both basic and translational research.
• Catalyzes the committing step for chondroitin sulfate, dermatan sulfate, and heparan sulfate proteoglycan biosynthesis.
• Required for formation of the glycosaminoglycan-protein linkage region on proteoglycan core proteins.
• Regulates extracellular matrix assembly and cell-surface proteoglycan function.
• Contributes to HNK-1 carbohydrate biosynthesis, which is essential for neural development and plasticity.
• Its expression is controlled by calcium-TonEBP signaling in intervertebral disc cells.
• Enzyme activity is influenced by phosphorylation and sulfation of the oligosaccharide substrate.
• Dimerization via conserved cysteine residues is required for catalytic function.
• Dysregulation is linked to intervertebral disc degeneration and musculoskeletal disease.
• Altered HNK-1 expression is associated with neurological disorders and brain region-specific pathologies.
• Represents a potential therapeutic target for diseases involving abnormal proteoglycan remodeling.
Molecular Mechanism of galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity
Substrate recognition and binding
In simple terms: The enzyme first grabs the sugar chain that is already attached to a protein and holds it in place.
GlcAT-I specifically recognizes the trisaccharide acceptor 3-O-(beta-D-galactosyl-(1->3)-beta-D-galactosyl-(1->4)-beta-D-xylosyl)-L-seryl-[protein]. The enzyme binds this galactosylgalactosylxylosylprotein substrate through interactions that are sensitive to the phosphorylation and sulfation state of the oligosaccharide, which can modulate catalytic efficiency. This substrate specificity ensures that glucuronic acid is added only to the correct linkage region intermediate during proteoglycan biosynthesis.
Catalytic transfer of glucuronic acid
In simple terms: The enzyme then transfers a glucuronic acid unit from a donor molecule onto the sugar chain.
The catalytic reaction uses UDP-alpha-D-glucuronate as the donor substrate and transfers the glucuronic acid moiety to the 3-hydroxyl group of the terminal galactose residue of the acceptor. The reaction produces the tetrasaccharide linkage region 3-O-(beta-D-GlcA-(1->3)-beta-D-Gal-(1->3)-beta-D-Gal-(1->4)-beta-D-Xyl)-L-seryl-[protein], along with UDP and a proton. This step is essential for the subsequent addition of the first hexosamine residue that initiates glycosaminoglycan chain polymerization.
Dimerization and structural requirements
In simple terms: Two copies of the enzyme must pair up for it to work properly.
Human GlcAT-I forms homodimers, and this dimerization is mediated by two crucial cysteine residues. Mutation of these cysteines disrupts dimer formation and abolishes functional activity, indicating that the dimeric state is required for catalysis. This structural feature distinguishes GlcAT-I from some other glycosyltransferases and provides a potential target for modulating its activity.
Regulation by calcium and TonEBP signaling
In simple terms: Calcium signals can turn up the production of this enzyme in certain tissues.
In cells of the intervertebral disc, activation of the transcription factor TonEBP by calcium controls the expression of beta1,3-glucuronosyltransferase-I, which is a key regulator of glycosaminoglycan synthesis. This calcium-TonEBP axis links extracellular signals to the transcriptional control of GO:0015018 activity, thereby influencing proteoglycan production and matrix homeostasis in the disc. Dysregulation of this pathway may contribute to disc degeneration.
Role in HNK-1 carbohydrate biosynthesis
In simple terms: The same enzyme activity also helps build a special sugar tag important for nerve cells.
GlcAT-I contributes to the biosynthesis of the HNK-1 carbohydrate epitope, a sulfated glucuronic acid-containing glycan that is expressed on neural cell adhesion molecules and other glycoproteins. HNK-1 biosynthesis is regulated in a tissue-specific manner by bisecting GlcNAc, which can influence the activity of glycosyltransferases involved in its synthesis. The HNK-1 glycan is critical for neural development, synaptic plasticity, and nervous system function, and its expression is region-specifically upregulated in the PRMT1-deficient brain.
Key Genes Involved in GO:0015018 galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity
The following genes and proteins are directly or functionally associated with GO:0015018 activity, its regulation, and its biological context.
| Gene | Major Role | Research Relevance |
|---|---|---|
| B3GAT3 | Encodes beta1,3-glucuronosyltransferase I (GlcAT-I), the enzyme that catalyzes GO:0015018 | Core enzyme for proteoglycan linkage region synthesis; target for KO, point mutation, and overexpression studies |
| B3GAT1 | Encodes a related glucuronosyltransferase involved in HNK-1 biosynthesis | Paralog with overlapping function in neural glycan synthesis; useful for comparative studies |
| B3GAT2 | Encodes another glucuronosyltransferase family member | Potential redundancy or tissue-specific roles in glycosaminoglycan synthesis |
| B4GALT7 | Encodes beta1,4-galactosyltransferase 7 (GalT-I), which acts upstream of GlcAT-I in linkage region assembly | Upstream enzyme whose activity is also modulated by substrate phosphorylation and sulfation |
| XYLT1 | Encodes xylosyltransferase 1, which initiates linkage region formation | Initiating enzyme for proteoglycan biosynthesis; context for GlcAT-I function |
| XYLT2 | Encodes xylosyltransferase 2, an isoform that adds xylose to serine residues | Isoform-specific roles in linkage region initiation |
| CHSY1 | Encodes chondroitin sulfate synthase 1, which acts downstream of GlcAT-I | Downstream polymerase for chondroitin sulfate chain elongation |
| CHPF | Encodes chondroitin polymerizing factor, involved in glycosaminoglycan chain polymerization | Downstream effector of linkage region maturation |
| EXT1 | Encodes exostosin glycosyltransferase 1, involved in heparan sulfate synthesis | Downstream enzyme for heparan sulfate chain assembly |
| EXT2 | Encodes exostosin glycosyltransferase 2, a partner of EXT1 | Downstream heparan sulfate polymerase complex component |
| TONEBP | Transcription factor activated by calcium that controls B3GAT3 expression | Regulator of GlcAT-I transcription in intervertebral disc cells |
| PRMT1 | Protein arginine methyltransferase 1, whose deficiency alters HNK-1 glycan expression | Epigenetic regulator linked to HNK-1 biosynthesis and neural function |
| MGAT3 | Encodes beta1,4-mannosyl-glycoprotein 4-beta-N-acetylglucosaminyltransferase, which adds bisecting GlcNAc | Regulates HNK-1 biosynthesis in a tissue-specific manner |
| UGT | UDP-glucuronosyltransferase family members that use UDP-glucuronate as donor | Related enzymes with similar donor substrate usage; context for glucuronosyltransferase biology |
| HNK-1 | Carbohydrate epitope whose biosynthesis depends on GlcAT-I activity | Neural cell adhesion and synaptic plasticity marker |
| SDC1 | Syndecan-1, a proteoglycan core protein that carries heparan sulfate chains | Model proteoglycan for studying linkage region synthesis |
| GPC1 | Glypican-1, a cell-surface heparan sulfate proteoglycan | Model proteoglycan for functional studies of GlcAT-I |
| DCN | Decorin, a small leucine-rich chondroitin/dermatan sulfate proteoglycan | Model proteoglycan for studying chondroitin sulfate linkage region |
How Is galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity Regulated?
GO:0015018 activity is regulated at multiple levels. Transcriptionally, the expression of B3GAT3 (encoding GlcAT-I) is controlled by the calcium-activated transcription factor TonEBP in intervertebral disc cells, linking extracellular calcium signals to glycosaminoglycan synthesis. At the substrate level, phosphorylation and sulfation of the oligosaccharide acceptor critically influence the catalytic efficiency of both GalT-I and GlcAT-I, providing a post-translational mechanism for fine-tuning linkage region assembly. Structurally, the enzyme requires dimerization mediated by two crucial cysteine residues for functional activity, and disruption of this dimer interface abolishes catalysis. Additionally, tissue-specific regulation of HNK-1 biosynthesis by bisecting GlcNAc suggests that glycosyltransferase competition and Golgi processing environment can modulate the flux through this activity. In the brain, PRMT1 deficiency leads to region-specific upregulation of HNK-1 glycan, indicating epigenetic and region-specific control mechanisms.
galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| B3GAT3 | Intervertebral disc degeneration; altered glycosaminoglycan synthesis | Knockout and overexpression in disc cells; point mutation of catalytic residues |
| B3GAT3 | Neural dysfunction via HNK-1 dysregulation | Neuron-specific knockout; HNK-1 expression analysis |
| PRMT1 | Region-specific HNK-1 upregulation in brain | PRMT1 knockout mouse; brain region-specific glycan profiling |
| MGAT3 | Tissue-specific regulation of HNK-1 biosynthesis | MGAT3 knockout and knock-in models; glycan analysis |
| B4GALT7 | Linkage region biosynthesis defects | Point mutation and knockout to study substrate specificity |
Intervertebral disc degeneration and musculoskeletal disease
GlcAT-I is a key regulator of glycosaminoglycan synthesis in cells of the intervertebral disc, and its expression is controlled by the calcium-TonEBP pathway. Dysregulation of this activity may lead to altered proteoglycan production and matrix homeostasis, contributing to disc degeneration and related musculoskeletal conditions. Because proteoglycans are essential for the osmotic and mechanical properties of the disc, changes in GO:0015018 activity could directly impact tissue function.
Neurological disorders and HNK-1-associated pathologies
The HNK-1 carbohydrate, whose biosynthesis depends on GlcAT-I activity, is critical for neural development, synaptic plasticity, and nervous system function. Altered HNK-1 expression has been observed in the PRMT1-deficient brain in a region-specific manner, suggesting that disruptions in this pathway may contribute to neurological disorders. Tissue-specific regulation of HNK-1 biosynthesis by bisecting GlcNAc further highlights the complexity of this system in neural tissues.
Cancer and proteoglycan remodeling
Proteoglycans are frequently remodeled in cancer, affecting cell adhesion, migration, and growth factor signaling. Although direct evidence linking GO:0015018 to cancer is limited in the provided literature, the enzyme's role in glycosaminoglycan biosynthesis places it within pathways that are commonly altered in tumor progression. Further research using knockout and overexpression models could clarify its contribution to cancer biology.
From galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the catalytic consequence of losing GlcAT-I activity? | B3GAT3 knockout cell lines and mouse models |
| How do specific amino acid changes affect enzyme function? | Point mutation of catalytic residues and cysteine residues involved in dimerization |
| Can wild-type GlcAT-I rescue proteoglycan synthesis defects? | Knock-in of tagged B3GAT3 for rescue and localization studies |
| What is the effect of GlcAT-I overexpression on glycosaminoglycan production? | Overexpression of B3GAT3 in cell lines and primary cells |
| How does TonEBP regulate B3GAT3 transcription? | Knockout or knockdown of TonEBP followed by B3GAT3 expression analysis |
| What is the role of HNK-1 in neural function? | Neuron-specific B3GAT3 knockout and HNK-1 glycan imaging |
How to Study the galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Glycosyltransferase activity assay | Catalytic transfer of glucuronic acid to acceptor substrate | Kinetic analysis and inhibitor testing |
| Mass spectrometry glycomics | Structure and abundance of linkage region and HNK-1 glycans | Glycan profiling in cells and tissues |
| Quantitative RT-PCR | B3GAT3 mRNA expression levels | Transcriptional regulation studies |
| RNA-seq | Global gene expression changes upon GlcAT-I manipulation | Pathway analysis and off-target assessment |
| Immunohistochemistry | Tissue distribution of HNK-1 and proteoglycans | Neural tissue and disease model analysis |
| Western blot | Protein expression and dimerization of GlcAT-I | Structural and functional studies |
| CRISPR knockout screening | Identification of genes required for GlcAT-I activity | Functional genomics and pathway discovery |
| Proteoglycan extraction and analysis | Glycosaminoglycan chain composition and size | Extracellular matrix studies |
Glycosyltransferase activity assays
Enzymatic activity of GlcAT-I can be measured using radiolabeled or fluorescently labeled UDP-glucuronic acid and the galactosylgalactosylxylosylprotein acceptor, followed by separation and quantification of the reaction product. These assays are essential for determining kinetic parameters and the effects of substrate modifications such as phosphorylation and sulfation.
Glycan profiling and mass spectrometry
Mass spectrometry-based glycomics and glycoproteomics can characterize the linkage region tetrasaccharide and HNK-1 epitope structures in cells and tissues. These methods allow researchers to assess how changes in GlcAT-I activity affect the abundance and composition of glycosaminoglycan chains and HNK-1 glycans.
Gene expression analysis
Quantitative RT-PCR, RNA-seq, and reporter assays can measure B3GAT3 mRNA levels and promoter activity in response to regulatory signals such as calcium-TonEBP activation. These approaches help define the transcriptional regulation of GO:0015018-related genes.
Imaging and immunohistochemistry
Immunohistochemistry and immunofluorescence using anti-HNK-1 antibodies can visualize the spatial distribution of HNK-1 glycans in neural tissues and other organs. These methods are valuable for linking GlcAT-I activity to tissue-specific functions and pathology.
How CRISPR Can Be Used to Study GO:0015018 galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity
Knockout
CRISPR knockout of B3GAT3 can abolish GO:0015018 activity, leading to loss of the tetrasaccharide linkage region and impaired glycosaminoglycan synthesis. These models are useful for studying the consequences of GlcAT-I deficiency on proteoglycan function, extracellular matrix organization, and HNK-1 expression.
Point Mutation
Point mutations can be introduced into B3GAT3 to dissect the roles of specific residues, such as the two crucial cysteines required for dimerization and catalytic activity. Such models help distinguish between effects on enzyme stability, substrate binding, and catalysis.
Knock-in
Knock-in of tagged or fluorescently labeled B3GAT3 allows real-time tracking of enzyme localization and dynamics in living cells. This approach can also be used to express mutant versions of the enzyme under endogenous regulatory control.
Overexpression
Overexpression of B3GAT3 can increase glycosaminoglycan production and HNK-1 biosynthesis, providing a gain-of-function system to study downstream effects on cell behavior and matrix properties. Overexpression models are also useful for testing whether increased GlcAT-I activity can rescue defects caused by upstream mutations.
How EDITGENE Supports galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity Research
Researchers studying galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity-related genes often need to determine whether a candidate gene is causally involved in proteoglycan biosynthesis, neural function, or disease progression. EDITGENE provides comprehensive CRISPR-based services to generate precisely engineered cell models that enable such functional studies.
Contact EDITGENE today to design your custom CRISPR model for galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity research.
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| B3GAT3 Knockout HEK293 Cell Line | EDJ-KQ8462 | Human | 26229 | Details Get a Quote |
| B3GAT1 Knockout HEK293 Cell Line | EDJ-KQ8678 | Human | 27087 | Details Get a Quote |
| B3GAT2 Knockout HEK293 Cell Line | EDJ-KQ9356 | Human | 135152 | Details Get a Quote |
| B3GAT3 Knockout A-549 Cell Line | EDJ-KQ34578 | Human | 26229 | Details Get a Quote |
| B3GAT3 Knockout HCT 116 Cell Line | EDJ-KQ34579 | Human | 26229 | Details Get a Quote |
| B3GAT3 Knockout HeLa Cell Line | EDJ-KQ34580 | Human | 26229 | Details Get a Quote |
| B3GAT1 Knockout HeLa Cell Line | EDJ-KQ55997 | Human | 27087 | Details Get a Quote |
| B3GAT2 Knockout HeLa Cell Line | EDJ-KQ58348 | Human | 135152 | Details Get a Quote |
| B3GAT1 Knockout A-549 Cell Line | EDJ-KQ64485 | Human | 27087 | Details Get a Quote |
| B3GAT2 Knockout A-549 Cell Line | EDJ-KQ66837 | Human | 135152 | Details Get a Quote |
| B3GAT1 Knockout HCT 116 Cell Line | EDJ-KQ72940 | Human | 27087 | Details Get a Quote |
| B3GAT2 Knockout HCT 116 Cell Line | EDJ-KQ75240 | Human | 135152 | Details Get a Quote |
Displaying Records 1 To 12 Of 12 Records
Frequently Asked Questions About galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity
What is galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity?
It is the enzymatic activity defined by GO:0015018 that transfers glucuronic acid from UDP-alpha-D-glucuronate to a galactosylgalactosylxylosylprotein acceptor during glycosaminoglycan-protein linkage region biosynthesis.
What gene encodes the enzyme for GO:0015018?
The human B3GAT3 gene encodes beta1,3-glucuronosyltransferase I (GlcAT-I), the enzyme responsible for this activity.
What is the role of GlcAT-I in proteoglycan synthesis?
GlcAT-I catalyzes the addition of glucuronic acid to the linkage region tetrasaccharide, a committing step for chondroitin sulfate, dermatan sulfate, and heparan sulfate chain assembly.
How is GlcAT-I activity regulated?
It is regulated transcriptionally by calcium-TonEBP signaling, and its substrate affinity is influenced by phosphorylation and sulfation of the oligosaccharide acceptor.
What diseases are associated with B3GAT3 mutations?
Dysregulation of GlcAT-I has been linked to intervertebral disc degeneration and neural disorders involving HNK-1 carbohydrate dysfunction.
What is the connection between GO:0015018 and HNK-1?
GlcAT-I activity contributes to the biosynthesis of the HNK-1 carbohydrate epitope, which is important for neural cell adhesion and synaptic plasticity.
How can I study GO:0015018 in the lab?
Common methods include glycosyltransferase activity assays, mass spectrometry glycomics, gene expression analysis, and CRISPR knockout or overexpression models.
What CRISPR models are available for B3GAT3?
Knockout, point mutation, knock-in, and overexpression models can be generated to study loss- and gain-of-function effects on proteoglycan synthesis.
Is GlcAT-I dimerization important for its activity?
Yes, human GlcAT-I forms homodimers mediated by two crucial cysteine residues, and dimerization is required for functional activity.
What is the substrate specificity of GlcAT-I?
It specifically recognizes the galactosylgalactosylxylosylprotein acceptor and uses UDP-alpha-D-glucuronate as the donor substrate.
Conclusion
GO:0015018, galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity, is a fundamental molecular function in proteoglycan biosynthesis, catalyzed by GlcAT-I. Its role in forming the glycosaminoglycan-protein linkage region makes it essential for extracellular matrix assembly, neural development via HNK-1, and tissue homeostasis. Dysregulation of this activity is implicated in intervertebral disc degeneration and neurological conditions, highlighting its potential as a therapeutic target. Advanced CRISPR models and functional genomics approaches will continue to illuminate the precise mechanisms and disease relevance of this critical enzyme.
References
- 1. Gulberti S et al.. 2005. Modifications of the glycosaminoglycan-linkage region of proteoglycans: phosphorylation and sulfation determine the activity of the human beta1,4-galactosyltransferase 7 and beta1,3-glucuronosyltransferase I.. ScientificWorldJournal 5:510-4 PMID: 16075146
- 2. Gulberti S et al.. 2005. Phosphorylation and sulfation of oligosaccharide substrates critically influence the activity of human beta1,4-galactosyltransferase 7 (GalT-I) and beta1,3-glucuronosyltransferase I (GlcAT-I) involved in the biosynthesis of the glycosaminoglycan-protein linkage region of proteoglycans.. J Biol Chem 280(2):1417-25 PMID: 15522873
- 3. Ouzzine M et al.. 2000. Structure/function of the human Ga1beta1,3-glucuronosyltransferase. Dimerization and functional activity are mediated by two crucial cysteine residues.. J Biol Chem 275(36):28254-60 PMID: 10842173
- 4. Hiyama A et al.. 2009. Activation of TonEBP by calcium controls {beta}1,3-glucuronosyltransferase-I expression, a key regulator of glycosaminoglycan synthesis in cells of the intervertebral disc.. J Biol Chem 284(15):9824-34 PMID: 19147493
- 5. Kizuka Y et al.. 2012. Regulated expression and neural functions of human natural killer-1 (HNK-1) carbohydrate.. Cell Mol Life Sci 69(24):4135-47 PMID: 22669261
- 6. Kawade H et al.. 2021. Tissue-Specific Regulation of HNK-1 Biosynthesis by Bisecting GlcNAc.. Molecules 26(17) PMID: 34500611
- 7. Fan C et al.. 2023. UDP-glucuronosyltransferase is involved in susceptibility of Chironomus kiiensis Tokunaga, 1936 (Diptera: Chironomidae) to insecticides.. Ecotoxicol Environ Saf 263:115353 PMID: 37586199
- 8. Hashimoto M et al.. 2020. Region-specific upregulation of HNK-1 glycan in the PRMT1-deficient brain.. Biochim Biophys Acta Gen Subj 1864(3):129509 PMID: 31884067
