GO:0004583 dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0004583 describes the enzymatic transfer of an alpha-D-glucosyl residue from dolichyl-phosphate D-glucose into a membrane lipid-linked oligosaccharide.
• This activity is a key step in the biosynthesis of the lipid-linked oligosaccharide (LLO) precursor used for N-linked protein glycosylation.
• The reaction is catalyzed by dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase, an enzyme that uses dolichyl-phosphate D-glucose as the glucosyl donor.
• Defects in LLO biosynthesis, including glucosyltransferase steps, can lead to congenital disorders of glycosylation (CDGs).
• Research on this activity uses gene knockout, point mutation, and knock-in cell models to dissect its role in glycosylation and disease.
• CRISPR-based screening and bioinformatics can identify modifiers and pathways linked to this enzymatic activity.
Description
Dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity (GO:0004583) is a molecular function defined as the catalysis of the transfer of an alpha-D-glucosyl residue from dolichyl-phosphate D-glucose into a membrane lipid-linked oligosaccharide. This reaction is part of the N-linked glycosylation pathway, which is essential for the proper folding, stability, and function of many secretory and membrane proteins. Researchers study this activity to understand how cells assemble the lipid-linked oligosaccharide precursor and how defects in this process contribute to human disease. The enzyme responsible for this activity belongs to the glycosyltransferase family and uses dolichyl-phosphate D-glucose as the glucosyl donor. Because glycosylation is involved in diverse biological processes, including cell signaling, immune recognition, and protein quality control, understanding GO:0004583 has broad implications for cell biology and medicine.
dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity At A Glance
| GO ID | GO:0004583 |
|---|---|
| GO term | dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity |
| Ontology | molecular_function |
| Synonym | none |
| Major function | Transfer of an alpha-D-glucosyl residue from dolichyl-phosphate D-glucose into a membrane lipid-linked oligosaccharide |
| Pathway context | N-linked glycosylation and lipid-linked oligosaccharide biosynthesis |
| Substrate | Dolichyl-phosphate D-glucose and membrane lipid-linked oligosaccharide |
| Product | Glucosylated lipid-linked oligosaccharide |
| Cellular location | Endoplasmic reticulum membrane |
What Is GO:0004583?
GO:0004583 is a molecular function term that describes the catalysis of the transfer of an alpha-D-glucosyl residue from dolichyl-phosphate D-glucose into a membrane lipid-linked oligosaccharide. In other words, it is the enzymatic step that adds a glucose molecule from a dolichol-linked donor to a growing oligosaccharide chain that is attached to a membrane lipid carrier. This activity is part of the biosynthetic pathway that produces the lipid-linked oligosaccharide precursor for N-linked glycosylation.
Why Is dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity Important in Cell Biology?
GO:0004583 is important because it represents a critical step in the assembly of the lipid-linked oligosaccharide (LLO) precursor, which is required for N-linked protein glycosylation. Glycosylation affects protein folding, stability, and function, and defects in this pathway cause congenital disorders of glycosylation (CDGs). Understanding this activity helps researchers dissect the molecular basis of glycosylation-related diseases and develop therapeutic strategies.
• It is a key enzymatic step in the N-linked glycosylation pathway.
• It contributes to the biosynthesis of the lipid-linked oligosaccharide precursor.
• Defects in this activity can lead to congenital disorders of glycosylation.
• It is essential for proper protein folding and quality control in the endoplasmic reticulum.
• It impacts cell signaling and immune recognition through glycosylation.
• It is a potential target for research on glycosylation-related diseases.
• It can be studied using CRISPR knockout and knock-in models.
• It is relevant to biotechnology applications involving glycoprotein production.
What Happens During dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity?
Substrate recognition and binding
In simple terms: The enzyme first grabs the sugar donor and the growing sugar chain.
The enzyme binds dolichyl-phosphate D-glucose, which serves as the glucosyl donor, and the membrane lipid-linked oligosaccharide acceptor. This binding positions the substrates for the transfer reaction.
Catalytic transfer of glucose
In simple terms: The enzyme moves a glucose unit from the donor to the growing chain.
The enzyme catalyzes the transfer of an alpha-D-glucosyl residue from dolichyl-phosphate D-glucose to the lipid-linked oligosaccharide. This reaction adds a glucose molecule to the oligosaccharide chain.
Product formation and release
In simple terms: The modified sugar chain is released to continue its assembly.
After the transfer, the glucosylated lipid-linked oligosaccharide is released and can undergo further processing in the N-linked glycosylation pathway.
Role in N-linked glycosylation
In simple terms: This step helps build the sugar tree that will be attached to proteins.
The glucosylated lipid-linked oligosaccharide is a precursor that is later transferred to nascent proteins in the endoplasmic reticulum. This step is essential for the proper assembly of the N-linked glycan.
Key Genes Involved in GO:0004583 dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity
The following genes and proteins are involved in or related to dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity and its pathway.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ALG5 | Dolichyl-phosphate beta-glucosyltransferase | Produces dolichyl-phosphate D-glucose, the donor for GO:0004583 |
| ALG6 | Alpha-1,3-glucosyltransferase | Adds the first glucose to the lipid-linked oligosaccharide |
| ALG8 | Alpha-1,3-glucosyltransferase | Adds the second glucose to the lipid-linked oligosaccharide |
| ALG10 | Alpha-1,2-glucosyltransferase | Adds the third glucose to the lipid-linked oligosaccharide |
| DOLK | Dolichol kinase | Phosphorylates dolichol to dolichyl phosphate |
| DPM1 | Dolichyl-phosphate mannosyltransferase | Synthesizes dolichyl-phosphate mannose |
| MPDU1 | Mannose-P-dolichol utilization defect 1 | Facilitates use of dolichyl-phosphate mannose |
| DDOST | Dolichyl-diphosphooligosaccharide-protein glycosyltransferase | Transfers the oligosaccharide to proteins |
| RPN1 | Ribophorin I | Component of the oligosaccharyltransferase complex |
| RPN2 | Ribophorin II | Component of the oligosaccharyltransferase complex |
| STT3A | Catalytic subunit of oligosaccharyltransferase | Transfers glycan to proteins |
| STT3B | Catalytic subunit of oligosaccharyltransferase | Transfers glycan to proteins |
| MAGT1 | Magnesium transporter 1 | Component of oligosaccharyltransferase complex |
| TUSC3 | Tumor suppressor candidate 3 | Component of oligosaccharyltransferase complex |
| DAD1 | Defender against cell death 1 | Component of oligosaccharyltransferase complex |
| OST4 | Oligosaccharyltransferase 4 | Component of oligosaccharyltransferase complex |
How Is dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity Regulated?
The activity of dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase is regulated by the availability of its substrates, dolichyl-phosphate D-glucose and the lipid-linked oligosaccharide acceptor. The expression of genes involved in lipid-linked oligosaccharide biosynthesis can be influenced by cellular stress and metabolic signals. However, specific regulatory mechanisms for this enzyme are not well defined in the provided literature.
dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ALG6 | Congenital disorder of glycosylation type Ic | Knockout or point-mutation cell lines |
| ALG8 | Congenital disorder of glycosylation type Ih | Knock-in of patient mutations |
| ALG10 | Congenital disorder of glycosylation type Ip | Overexpression and knockout models |
| DOLK | Congenital disorder of glycosylation type Im | Knockout cell lines |
| MPDU1 | Congenital disorder of glycosylation type If | Point-mutation knock-in |
Congenital disorders of glycosylation (CDGs)
Defects in the N-linked glycosylation pathway, including steps involving glucosyltransferases, can cause congenital disorders of glycosylation (CDGs). These disorders often present with neurological and developmental symptoms. Mutations in genes such as ALG6, ALG8, and ALG10, which are related to glucosyltransferase activities, have been associated with CDGs.
Cancer and glycosylation changes
Altered glycosylation is a hallmark of cancer, and changes in N-linked glycosylation can affect tumor cell adhesion, signaling, and immune evasion. Although direct links between GO:0004583 and cancer are not established in the provided literature, the pathway it belongs to is relevant to cancer biology.
Neurological disorders
Glycosylation defects often manifest as neurological disorders, including developmental delay and seizures. The lipid-linked oligosaccharide biosynthesis pathway, which includes GO:0004583, is critical for normal brain development.
From dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of the glucosyltransferase affect LLO assembly? | CRISPR knockout cell line |
| How do patient mutations alter enzyme function? | Point-mutation knock-in |
| Can tagged enzyme be used for localization studies? | Tagged knock-in |
| Does overexpression alter glycosylation flux? | Overexpression cell line |
| Which genes modify the glycosylation defect? | CRISPR library screening |
| What are the transcriptomic changes upon enzyme loss? | RNA-seq of knockout cells |
How to Study the dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Mass spectrometry | Glycan structures | Analysis of N-linked glycosylation |
| Lectin blotting | Glycan epitopes | Detection of glycosylation changes |
| Enzymatic assay | Transferase activity | Direct measurement of GO:0004583 |
| CRISPR knockout | Gene function | Loss-of-function studies |
| RNA-seq | Transcriptome | Gene expression changes |
| Proteomics | Protein abundance | Global protein changes |
| Immunofluorescence | Protein localization | Subcellular localization |
Glycosylation analysis
Mass spectrometry and lectin blotting can be used to analyze the glycan structures on proteins, revealing changes in N-linked glycosylation when GO:0004583 activity is perturbed.
Enzymatic assays
In vitro enzymatic assays using radiolabeled dolichyl-phosphate D-glucose can measure the transferase activity directly.
CRISPR screening
Genome-wide CRISPR knockout screens can identify genes that are essential for glycosylation or that modify the phenotype of cells with defective GO:0004583 activity.
Proteomics and transcriptomics
RNA-seq and proteomics can reveal global changes in gene expression and protein abundance upon loss or gain of function of the enzyme.
How CRISPR Can Be Used to Study GO:0004583 dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity
Knockout
CRISPR knockout of the gene encoding the glucosyltransferase can abolish GO:0004583 activity, leading to defective lipid-linked oligosaccharide assembly and altered glycosylation. Such models are useful for studying the consequences of loss of function.
Point Mutation
Point mutations identified in patients can be introduced using CRISPR to create isogenic cell lines that mimic disease-associated alleles. These models help dissect the functional impact of specific mutations on enzyme activity.
Knock-in
Knock-in of a tagged version of the enzyme allows for localization and interaction studies without altering its endogenous regulation. This approach can also be used to introduce reporter genes for high-throughput screening.
Overexpression
Overexpression of the enzyme can be achieved by CRISPR activation or by inserting a strong promoter, enabling studies of increased glycosylation flux and its effects on cellular physiology.
How EDITGENE Supports dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity Research
Researchers studying dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity-related genes often need to determine whether a candidate gene is causally involved in glycosylation and disease. EDITGENE provides a comprehensive suite of CRISPR services to accelerate this research.
Contact EDITGENE today to design your custom CRISPR model for dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity research.
Frequently Asked Questions About dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity
What is dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity?
It is a molecular function (GO:0004583) that catalyzes the transfer of an alpha-D-glucosyl residue from dolichyl-phosphate D-glucose into a membrane lipid-linked oligosaccharide.
What genes are involved in dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity?
Genes such as ALG5, ALG6, ALG8, and ALG10 are involved in the pathway that includes this activity.
What is the role of GO:0004583 in glycosylation?
It is a step in the biosynthesis of the lipid-linked oligosaccharide precursor for N-linked glycosylation.
Which diseases are associated with defects in this activity?
Defects in the pathway can cause congenital disorders of glycosylation (CDGs).
How can I study dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity?
You can use enzymatic assays, CRISPR knockout models, and glycosylation analysis methods.
What is the substrate for this enzyme?
The substrate is dolichyl-phosphate D-glucose and a membrane lipid-linked oligosaccharide.
Where does this activity occur in the cell?
It occurs in the endoplasmic reticulum membrane.
What are the synonyms for GO:0004583?
There are no synonyms listed for this term.
Can CRISPR be used to study this activity?
Yes, CRISPR knockout, point mutation, and knock-in models can be used to study the enzyme and its pathway.
What model systems are suitable for studying this activity?
Cell lines with knockout or knock-in of the relevant genes are commonly used.
Conclusion
Dolichyl-phosphate-glucose-glycolipid alpha-glucosyltransferase activity (GO:0004583) is a key enzymatic step in N-linked glycosylation, and its study is important for understanding glycosylation-related diseases. Researchers can leverage CRISPR models and EDITGENE services to dissect its function and regulation.
References
- 1. Nakajima M et al.. 2014. 1,2-β-Oligoglucan phosphorylase from Listeria innocua.. PLoS One 9(3):e92353 PMID: 24647662
