GO:0015165 pyrimidine nucleotide-sugar transmembrane transporter activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0015165 describes the molecular function of transferring pyrimidine nucleotide-sugars across biological membranes.
• Pyrimidine nucleotide-sugars are pyrimidine nucleotides linked to monosaccharides, such as UDP-galactose, UDP-glucose, UDP-N-acetylglucosamine, and CMP-sialic acid.
• Transporters with this activity are typically multi-pass membrane proteins localized to the endoplasmic reticulum or Golgi apparatus.
• Substrate recognition depends on specific transmembrane helices and conserved amino acid residues, as shown for UDP-galactose, CMP-sialic acid, and UDP-N-acetylglucosamine transporters.
• These transporters are essential for glycosylation, glycoprotein and glycolipid biosynthesis, and cellular nucleotide-sugar homeostasis.
• Dysregulation of nucleotide-sugar transport is linked to developmental defects, immune dysfunction, and cancer-associated glycosylation changes.
Description
Pyrimidine nucleotide-sugar transmembrane transporter activity (GO:0015165) is a molecular function that enables the movement of pyrimidine nucleotide-sugars across cellular membranes. These molecules consist of a pyrimidine nucleotide (such as uridine diphosphate, UDP, or cytidine monophosphate, CMP) glycosidically linked to a monosaccharide or monosaccharide derivative. This transport activity is critical for supplying the lumen of the endoplasmic reticulum (ER) and Golgi apparatus with the nucleotide-sugar substrates required for glycosylation reactions. Researchers study GO:0015165 because it sits at the intersection of nucleotide metabolism, membrane transport, and glycobiology. The transporters that carry out this function are members of the solute carrier (SLC) family, including SLC35A3 and SLC35B1, and they exhibit distinct substrate specificities and transport mechanisms. Understanding these proteins at the molecular level informs studies of congenital disorders of glycosylation, cancer biology, and the development of targeted therapeutics. This article synthesizes authoritative QuickGO annotation data and verified PubMed literature to provide a research-grade overview of GO:0015165, covering its definition, mechanism, key genes, disease relevance, and experimental approaches for functional characterization.
pyrimidine nucleotide-sugar transmembrane transporter activity At A Glance
| GO ID | GO:0015165 |
|---|---|
| GO term | pyrimidine nucleotide-sugar transmembrane transporter activity |
| Ontology | molecular_function |
| Synonym | None listed in QuickGO |
| Major function | Transfers pyrimidine nucleotide-sugars across membranes |
| Substrates | UDP-galactose, UDP-glucose, UDP-N-acetylglucosamine, UDP-N-acetylgalactosamine, CMP-sialic acid |
| Cellular localization | Endoplasmic reticulum and Golgi apparatus membranes |
| Representative genes | SLC35A3, SLC35B1, and related SLC35 family members |
| Transport mechanism | Antiport with nucleotide monophosphates |
What Is GO:0015165?
GO:0015165, pyrimidine nucleotide-sugar transmembrane transporter activity, is defined as the transfer of a pyrimidine nucleotide-sugar from one side of a membrane to the other. Pyrimidine nucleotide-sugars are pyrimidine nucleotides in glycosidic linkage with a monosaccharide or monosaccharide derivative. This activity is a molecular function that facilitates the transmembrane movement of substrates such as UDP-galactose, UDP-glucose, UDP-N-acetylglucosamine, UDP-N-acetylgalactosamine, and CMP-sialic acid. Transporters with this activity are integral membrane proteins that typically function as antiporters, exchanging a nucleotide-sugar for a nucleotide monophosphate.
Why Is pyrimidine nucleotide-sugar transmembrane transporter activity Important in Cell Biology?
GO:0015165 is essential for glycosylation, a fundamental post-translational modification that affects protein folding, stability, and cell-cell recognition. By supplying nucleotide-sugars to the ER and Golgi lumen, these transporters directly influence the synthesis of glycoproteins, glycolipids, and proteoglycans. Defects in this activity can lead to congenital disorders of glycosylation, immune deficiencies, and cancer progression, making it a significant target for both basic research and therapeutic development.
• Enables glycosylation by providing nucleotide-sugar substrates to the ER and Golgi lumen.
• Supports glycoprotein and glycolipid biosynthesis, impacting cell signaling and adhesion.
• Maintains cellular nucleotide-sugar homeostasis and nucleotide metabolism.
• Mutations in transporters with this activity cause congenital disorders of glycosylation.
• Altered expression is associated with cancer and immune dysfunction.
• Provides targets for antiviral and anticancer drug development.
• Facilitates studies of membrane protein structure-function relationships.
• Contributes to developmental processes in plants and animals.
• Influences host-pathogen interactions through glycosylation changes.
• Serves as a model for understanding substrate specificity in SLC transporters.
What Happens During pyrimidine nucleotide-sugar transmembrane transporter activity?
Substrate Recognition and Binding
In simple terms: The transporter first recognizes and grabs the correct nucleotide-sugar molecule.
Transporters with GO:0015165 activity selectively bind pyrimidine nucleotide-sugars such as UDP-galactose, UDP-N-acetylglucosamine, or CMP-sialic acid. Specific amino acid residues, including conserved Glu-47 and Lys-50 in SLC35A3, are critical for substrate recognition and binding. Studies using chimeric transporters have shown that different sets of transmembrane helices are utilized for the specific recognition of UDP-galactose versus CMP-sialic acid. This selectivity ensures that the correct nucleotide-sugar is transported for downstream glycosylation reactions.
Translocation Across the Membrane
In simple terms: The transporter moves the nucleotide-sugar from one side of the membrane to the other.
After binding, the transporter undergoes conformational changes to translocate the nucleotide-sugar across the lipid bilayer. This process is often coupled to the exchange of a nucleotide monophosphate, such as UMP or CMP, in an antiport mechanism. For example, SLC35A3 functions as a UDP-N-acetylglucosamine/UMP antiporter, while SLC35B1 displays asymmetrical affinities for ATP transport across the ER membrane. The transport is energy-independent, relying on concentration gradients established by nucleotide metabolism.
Substrate Release and Recycling
In simple terms: The transporter releases the nucleotide-sugar inside the organelle and resets for another cycle.
Once the nucleotide-sugar is delivered into the ER or Golgi lumen, it is released and becomes available for glycosyltransferase reactions. The transporter then returns to its original conformation to accept another substrate molecule. This cycling ensures a continuous supply of nucleotide-sugars for glycosylation. The antiport mechanism allows the transporter to exchange the incoming nucleotide-sugar for a nucleotide monophosphate, maintaining the balance of luminal nucleotides.
Integration with Glycosylation Pathways
In simple terms: The transported sugars are used to build complex carbohydrate structures on proteins and lipids.
Nucleotide-sugars transported by GO:0015165 activity serve as donors for glycosyltransferases in the ER and Golgi. UDP-galactose and UDP-glucose are used for galactosylation and glucosylation of proteins and lipids. UDP-N-acetylglucosamine is essential for O-GlcNAcylation and N-glycan branching. CMP-sialic acid is required for sialylation of glycoproteins and glycolipids. Disruption of this transport activity leads to incomplete glycosylation and cellular dysfunction.
Key Genes Involved in GO:0015165 pyrimidine nucleotide-sugar transmembrane transporter activity
The following genes encode proteins that exhibit pyrimidine nucleotide-sugar transmembrane transporter activity or are directly involved in this function, based on verified literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SLC35A3 | UDP-N-acetylglucosamine/UMP antiporter in Golgi | Congenital disorder of glycosylation, substrate specificity studies |
| SLC35B1 | Broad range di- and tri-nucleotide exchanger in ER | ER membrane transport, ATP transport asymmetry |
| SLC35A2 | UDP-galactose transporter | Galactosylation defects, developmental disorders |
| SLC35A1 | CMP-sialic acid transporter | Sialylation defects, immune disorders |
| SLC35C1 | GDP-fucose transporter (related family) | Not directly cited in provided references |
| SLC35D1 | UDP-glucuronic acid/UDP-N-acetylgalactosamine transporter | Not directly cited in provided references |
| UGT1 | UDP-galactose transporter in rice | Plant glycosylation, cell wall biosynthesis |
| UGT2 | UDP-glucose transporter in rice | Plant nucleotide-sugar transport |
| CMP-SiaT | CMP-sialic acid transporter | Sialylation, substrate recognition |
| UDP-GalT | UDP-galactose transporter | Galactosylation, chimeric transporter studies |
| SLC35A4 | Putative nucleotide-sugar transporter | Not directly cited in provided references |
| SLC35B2 | PAPS transporter (related family) | Not directly cited in provided references |
| SLC35B3 | PAPS transporter (related family) | Not directly cited in provided references |
| SLC35B4 | UDP-xylose/UDP-N-acetylglucosamine transporter | Not directly cited in provided references |
| SLC35D2 | UDP-N-acetylglucosamine transporter | Not directly cited in provided references |
| SLC35E1 | Putative nucleotide-sugar transporter | Not directly cited in provided references |
| SLC35F1 | Putative nucleotide-sugar transporter | Not directly cited in provided references |
How Is pyrimidine nucleotide-sugar transmembrane transporter activity Regulated?
The activity of pyrimidine nucleotide-sugar transporters is regulated at multiple levels. Substrate availability and nucleotide-sugar concentrations in the cytosol influence transport rates. Conserved amino acid residues, such as Glu-47 and Lys-50 in SLC35A3, are critical for antiport activity and can be modulated by mutations. The expression of transporter genes is regulated in response to cellular demands for glycosylation, although specific transcriptional regulators are not detailed in the provided references. Additionally, the antiport mechanism itself provides a form of regulation by coupling substrate import to nucleotide monophosphate export.
pyrimidine nucleotide-sugar transmembrane transporter activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SLC35A3 | Congenital disorder of glycosylation | Knockout and point-mutation cell models |
| SLC35A1 | Sialylation defects, immune dysfunction | Knockout and overexpression models |
| SLC35B1 | ER stress and metabolic disorders | Knockout and tagged knock-in models |
| SLC35A2 | Developmental disorders, galactosylation defects | Knock-in and knockout models |
| UGT1/UGT2 | Plant development and cell wall integrity | Plant knockout and overexpression models |
Congenital Disorders of Glycosylation
Mutations in genes encoding pyrimidine nucleotide-sugar transporters, such as SLC35A3, can cause congenital disorders of glycosylation (CDG). These disorders present with developmental delay, seizures, and skeletal abnormalities due to defective glycosylation of proteins and lipids. Studies on SLC35A3 have shown that conserved residues critical for UDP-N-acetylglucosamine transport are essential for normal Golgi function, and their mutation leads to disease phenotypes.
Cancer and Altered Glycosylation
Altered expression of nucleotide-sugar transporters is associated with cancer progression and metastasis. Changes in UDP-galactose and CMP-sialic acid transport can lead to aberrant glycosylation patterns on cell surface proteins, affecting cell adhesion, signaling, and immune recognition. Targeting these transporters may provide therapeutic opportunities for cancer treatment.
Immune Dysfunction and Infection
CMP-sialic acid transport is essential for sialylation of immune cell surface receptors, and defects can lead to immune deficiencies. Additionally, many pathogens exploit host nucleotide-sugar transporters for their own glycosylation or entry, making these proteins relevant to infectious disease research.
From pyrimidine nucleotide-sugar transmembrane transporter activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of SLC35A3 affect Golgi glycosylation? | SLC35A3 knockout cell line |
| Which residues are critical for UDP-N-acetylglucosamine transport? | Point-mutation knock-in of Glu-47 and Lys-50 |
| How does SLC35B1 mediate ATP transport asymmetry? | Tagged knock-in for localization and transport assays |
| Can overexpression of UDP-galactose transporter rescue glycosylation defects? | Overexpression cell model |
| What is the substrate specificity of CMP-sialic acid transporter? | Chimeric transporter knock-in models |
| Does SLC35A1 knockout alter immune cell sialylation? | Knockout mouse or cell line |
How to Study the pyrimidine nucleotide-sugar transmembrane transporter activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radioactive transport assay | Nucleotide-sugar transport activity | Substrate specificity and kinetics |
| Mass spectrometry | Glycan structures and composition | Glycosylation profiling |
| Lectin blotting | Specific glycan epitopes | Detection of sialylation or galactosylation changes |
| Site-directed mutagenesis | Amino acid residue function | Identifying critical residues for transport |
| Chimeric transporter analysis | Transmembrane helix contribution | Substrate recognition mapping |
| Fluorescence microscopy | Subcellular localization | ER/Golgi targeting |
| CRISPR knockout | Gene function loss | Phenotypic analysis of transporter deficiency |
| Overexpression | Gain-of-function effects | Rescue experiments and glycosylation enhancement |
Transport Assays
Radioactive or fluorescently labeled nucleotide-sugars can be used to measure transport activity in isolated membrane vesicles or intact cells. These assays determine substrate specificity, kinetics, and antiport mechanisms. For example, SLC35B1 ATP transport was characterized using asymmetrical affinity measurements.
Glycosylation Analysis
Mass spectrometry, lectin blotting, and HPLC can assess glycosylation patterns in cells with altered transporter expression. These methods reveal changes in N-glycans, O-glycans, and glycolipids resulting from defective nucleotide-sugar transport.
Mutagenesis and Chimeric Studies
Site-directed mutagenesis and chimeric transporter construction are used to identify residues and transmembrane helices critical for substrate recognition. These approaches have revealed that different sets of transmembrane helices are utilized for UDP-galactose versus CMP-sialic acid recognition.
Localization and Imaging
Fluorescence microscopy with tagged transporters (e.g., GFP or HA) can determine subcellular localization to the ER or Golgi. Co-localization with organelle markers confirms proper targeting and helps assess trafficking defects.
How CRISPR Can Be Used to Study GO:0015165 pyrimidine nucleotide-sugar transmembrane transporter activity
Knockout
CRISPR knockout of genes encoding pyrimidine nucleotide-sugar transporters, such as SLC35A3 or SLC35A1, allows researchers to study loss-of-function phenotypes. Knockout cell lines exhibit defective glycosylation, altered Golgi morphology, and changes in cell surface glycan profiles. These models are valuable for understanding the role of specific transporters in development and disease.
Point Mutation
CRISPR-mediated point mutations can introduce specific amino acid substitutions, such as Glu-47 or Lys-50 in SLC35A3, to dissect their roles in substrate binding and antiport activity. These models help confirm the functional importance of conserved residues identified in biochemical studies.
Knock-in
Knock-in of tagged transporters (e.g., GFP or HA) enables real-time imaging and proteomic analysis of transporter localization and interactions. Knock-in of disease-associated mutations can create isogenic models for studying congenital disorders of glycosylation.
Overexpression
Overexpression of nucleotide-sugar transporters can rescue glycosylation defects or enhance specific glycan structures. This approach is useful for producing recombinant glycoproteins with defined glycosylation patterns and for studying transport capacity.
How EDITGENE Supports pyrimidine nucleotide-sugar transmembrane transporter activity Research
Researchers studying pyrimidine nucleotide-sugar transmembrane transporter activity-related genes often need to determine whether a candidate gene is causally involved in glycosylation, development, or disease. EDITGENE provides comprehensive CRISPR-based services to accelerate this research, from gene knockout to precise point mutations and knock-in models.
Contact EDITGENE today to design your custom CRISPR model for pyrimidine nucleotide-sugar transmembrane transporter activity research.
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SLC35A1 Knockout HEK293 Cell Line | EDJ-KQ2703 | Human | 10559 | Details Get a Quote |
| SLC35A2 Knockout HEK293 Cell Line | EDJ-KQ3494 | Human | 7355 | Details Get a Quote |
| SLC35A4 Knockout HEK293 Cell Line | EDJ-KQ7433 | Human | 113829 | Details Get a Quote |
| SLC35D1 Knockout HEK293 Cell Line | EDJ-KQ7872 | Human | 23169 | Details Get a Quote |
| SLC35A5 Knockout HEK293 Cell Line | EDC08375 | Human | 55032 | Details Get a Quote |
| SLC35A5 Knockout HCT 116 Cell Line | EDJ-KQ46038 | Human | 55032 | Details Get a Quote |
| SLC35A5 Knockout HeLa Cell Line | EDJ-KQ46039 | Human | 55032 | Details Get a Quote |
| SLC35A5 Knockout A-549 Cell Line | EDJ-KQ44818 | Human | 55032 | Details Get a Quote |
| SLC35A1 Knockout A-549 Cell Line | EDJ-KQ23541 | Human | 10559 | Details Get a Quote |
| SLC35A1 Knockout HCT 116 Cell Line | EDJ-KQ23542 | Human | 10559 | Details Get a Quote |
| SLC35A1 Knockout HeLa Cell Line | EDJ-KQ23543 | Human | 10559 | Details Get a Quote |
| SLC35A2 Knockout A-549 Cell Line | EDJ-KQ25287 | Human | 7355 | Details Get a Quote |
| SLC35A2 Knockout HCT 116 Cell Line | EDJ-KQ25288 | Human | 7355 | Details Get a Quote |
| SLC35A2 Knockout HeLa Cell Line | EDJ-KQ25289 | Human | 7355 | Details Get a Quote |
| SLC35A4 Knockout A-549 Cell Line | EDJ-KQ32638 | Human | 113829 | Details Get a Quote |
Displaying Records 1 To 15 Of 25 Records
Frequently Asked Questions About pyrimidine nucleotide-sugar transmembrane transporter activity
What is pyrimidine nucleotide-sugar transmembrane transporter activity?
It is a molecular function (GO:0015165) that enables the transfer of pyrimidine nucleotide-sugars, such as UDP-galactose or CMP-sialic acid, across a membrane.
What genes are involved in pyrimidine nucleotide-sugar transmembrane transporter activity?
Key genes include SLC35A3, SLC35B1, SLC35A1, SLC35A2, and plant UGT1/UGT2, which encode transporters for UDP-N-acetylglucosamine, ATP, CMP-sialic acid, and UDP-galactose.
What is the function of SLC35A3?
SLC35A3 is a Golgi-associated transporter that functions as a UDP-N-acetylglucosamine/UMP antiporter, and its conserved residues Glu-47 and Lys-50 are critical for this activity.
How does CMP-sialic acid transporter recognize its substrate?
It uses specific transmembrane helices for CMP-sialic acid recognition, as shown by chimeric transporter studies.
What diseases are associated with defects in nucleotide-sugar transport?
Defects can cause congenital disorders of glycosylation, immune dysfunction, and cancer-associated glycosylation changes.
What methods are used to study pyrimidine nucleotide-sugar transporters?
Common methods include radioactive transport assays, mass spectrometry, lectin blotting, site-directed mutagenesis, and fluorescence microscopy.
Can CRISPR be used to study these transporters?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are widely used to dissect transporter function and disease relevance.
What is the role of SLC35B1?
SLC35B1 is a broad-range di- and tri-nucleotide exchanger in the ER membrane with asymmetrical affinities for ATP transport.
Are there plant homologs of these transporters?
Yes, rice UGT1 and UGT2 are nucleotide sugar transporters capable of transporting UDP-galactose and UDP-glucose.
How does EDITGENE support research on GO:0015165?
EDITGENE provides CRISPR knockout, point mutation, knock-in, overexpression, library screening, and bioinformatics services for genes involved in this activity.
Conclusion
Pyrimidine nucleotide-sugar transmembrane transporter activity (GO:0015165) is a fundamental molecular function that supplies the ER and Golgi with nucleotide-sugars for glycosylation. The transporters that carry out this activity, including SLC35A3 and SLC35B1, are critical for protein and lipid glycosylation, and their dysfunction is linked to congenital disorders, immune defects, and cancer. Continued research using CRISPR-based models and advanced biochemical assays will further elucidate the mechanisms and therapeutic potential of these transporters.
References
- 1. Seino J et al.. 2010. Characterization of rice nucleotide sugar transporters capable of transporting UDP-galactose and UDP-glucose.. J Biochem 148(1):35-46 PMID: 20305274
- 2. Schwarzbaum PJ et al.. 2022. The broad range di- and tri-nucleotide exchanger SLC35B1 displays asymmetrical affinities for ATP transport across the ER membrane.. J Biol Chem 298(4):101537 PMID: 35041824
- 3. Toscanini MA et al.. 2019. Conserved Glu-47 and Lys-50 residues are critical for UDP-N-acetylglucosamine/UMP antiport activity of the mouse Golgi-associated transporter Slc35a3.. J Biol Chem 294(26):10042-10054 PMID: 31118275
- 4. Takeshima-Futagami T et al.. 2012. Amino acid residues important for CMP-sialic acid recognition by the CMP-sialic acid transporter: analysis of the substrate specificity of UDP-galactose/CMP-sialic acid transporter chimeras.. Glycobiology 22(12):1731-40 PMID: 22833315
- 5. Segawa H et al.. 2002. Human and Drosophila UDP-galactose transporters transport UDP-N-acetylgalactosamine in addition to UDP-galactose.. Eur J Biochem 269(1):128-38 PMID: 11784306
- 6. Aoki K et al.. 2001. Substrate recognition by UDP-galactose and CMP-sialic acid transporters. Different sets of transmembrane helices are utilized for the specific recognition of UDP-galactose and CMP-sialic acid.. J Biol Chem 276(24):21555-61 PMID: 11279205
