GO:0140929 mannose:sodium symporter activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0140929 mannose:sodium symporter activity is a molecular_function that enables sodium-coupled transport of D-mannose across membranes, as defined by the reaction D-mannose(out) + Na+(out) = D-mannose(in) + Na+(in).
• This activity belongs to the sodium-dependent glucose/galactose transporter family, which includes SGLT1 (SLC5A1), SGLT2 (SLC5A2), and SGLT5 (SLC5A10) that can transport mannose with varying selectivity.
• Mannose transport via sodium symporters is relevant to intestinal sugar absorption, renal reabsorption, and metabolic homeostasis, with implications for diabetes and metabolic disorders.
• Sodium oligomannate, a mannose-derived compound, can activate enteroendocrine-vagal afferent pathways, linking mannose transport to gut-brain signaling in Alzheimer's disease models.
• Bacterial homologs of sodium:sugar symporters provide structural and mechanistic insights into the transport cycle and cation coupling.
• CRISPR-based knockout, point mutation, and knock-in models are essential for dissecting the physiological roles of mannose:sodium symporters in health and disease.
Description
Mannose:sodium symporter activity (GO:0140929) is a molecular function that enables the transfer of D-mannose across a membrane coupled to sodium ion transport, according to the reaction D-mannose(out) + Na+(out) = D-mannose(in) + Na+(in). This activity is part of the broader family of sodium-dependent sugar transporters, which are critical for nutrient uptake in epithelial tissues. Understanding this activity is important because mannose is a key monosaccharide involved in glycoprotein synthesis and energy metabolism, and its transport is linked to various physiological and pathological processes. Researchers study mannose:sodium symporters to elucidate mechanisms of sugar selectivity, ion coupling, and their roles in diseases such as diabetes and Alzheimer's disease.
mannose:sodium symporter activity At A Glance
| GO ID | GO:0140929 |
|---|---|
| GO term | mannose:sodium symporter activity |
| Ontology | molecular_function |
| Synonym | none |
| Major function | Sodium-coupled transport of D-mannose across membranes |
| Reaction | D-mannose(out) + Na+(out) = D-mannose(in) + Na+(in) |
| Related transporters | SGLT family (SLC5A1, SLC5A2, SLC5A10, etc.) |
| Tissue distribution | Intestine, kidney, and other epithelial tissues |
| Physiological role | Dietary mannose absorption and reabsorption |
What Is GO:0140929?
Mannose:sodium symporter activity (GO:0140929) is defined as the transfer of a solute or solutes from one side of a membrane to the other according to the reaction: D-mannose(out) + Na+(out) = D-mannose(in) + Na+(in). In other words, it is a secondary active transport process where the inward movement of sodium ions down their electrochemical gradient drives the uptake of mannose against its concentration gradient.
Why Is mannose:sodium symporter activity Important in Cell Biology?
Mannose:sodium symporter activity is important because it mediates the uptake of mannose, a sugar essential for protein glycosylation and cellular metabolism. Dysregulation of mannose transport has been implicated in metabolic disorders and neurological conditions. Moreover, understanding this activity provides insights into the general mechanisms of sodium-coupled sugar transport, which is targeted by drugs like SGLT2 inhibitors for diabetes treatment.
• Facilitates intestinal absorption of dietary mannose.
• Contributes to renal reabsorption of mannose, preventing its loss in urine.
• Plays a role in gut-brain signaling via enteroendocrine cells.
• Provides a model for studying sodium-coupled sugar transport mechanisms.
• Relevant to diabetes and metabolic syndrome due to altered sugar handling.
• Potential target for modulating mannose metabolism in cancer and glycosylation disorders.
• Bacterial homologs inform structural and functional studies.
• May influence drug pharmacokinetics by competing with other sugars.
• Linked to Alzheimer's disease through sodium oligomannate effects.
• Essential for understanding substrate selectivity among SGLT family members.
What Happens During mannose:sodium symporter activity?
Sodium Binding and Conformational Change
In simple terms: Sodium ions bind to the transporter, causing it to change shape.
The transport cycle begins with the binding of sodium ions to the symporter on the extracellular side. This binding induces a conformational change that creates a high-affinity site for mannose.
Mannose Binding and Translocation
In simple terms: Mannose binds and is carried across the membrane.
Following sodium binding, D-mannose binds to the transporter. The protein then undergoes a conformational shift that exposes the binding sites to the intracellular side, allowing the release of both sodium and mannose into the cytoplasm.
Cation Coupling and Stoichiometry
In simple terms: Sodium and mannose move together in a fixed ratio.
The transport is coupled with a stoichiometry of 1 sodium ion per mannose molecule, as defined by the reaction. This coupling ensures that mannose uptake is driven by the sodium gradient maintained by Na+/K+-ATPase.
Substrate Selectivity
In simple terms: The transporter prefers mannose but can also transport other sugars.
Sodium-dependent sugar transporters exhibit varying selectivity; for example, hSGLT5 shows high selectivity for mannose and fructose, while SGLT1 primarily transports glucose and galactose. This selectivity is determined by specific amino acid residues in the binding pocket.
Key Genes Involved in GO:0140929 mannose:sodium symporter activity
The following genes encode proteins that exhibit mannose:sodium symporter activity or are closely related to this function.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SLC5A1 | Sodium-glucose cotransporter 1 (SGLT1); transports glucose and galactose, may transport mannose | Studied for intestinal sugar absorption and diabetes |
| SLC5A2 | Sodium-glucose cotransporter 2 (SGLT2); renal glucose reabsorption | Target of SGLT2 inhibitors for diabetes; may transport mannose |
| SLC5A10 | Sodium-glucose cotransporter 5 (SGLT5); high mannose selectivity | Key model for mannose transport studies |
| SLC5A4 | Sodium-glucose cotransporter 3 (SGLT3); acts as a glucose sensor | May have mannose transport activity |
| SLC5A9 | Sodium-glucose cotransporter 4 (SGLT4); transports mannose and fructose | Expressed in intestine and kidney |
| SLC5A11 | Sodium-glucose cotransporter 6 (SGLT6); inositol and glucose transport | Potential mannose transport |
| SLC5A8 | Sodium-coupled monocarboxylate transporter 1 (SMCT1) | May transport mannose in some contexts |
| SLC5A12 | Sodium-coupled monocarboxylate transporter 2 (SMCT2) | Related to sugar transport |
| SLC5A5 | Sodium-iodide symporter (NIS) | Not a mannose transporter but shares structural homology |
| SLC5A6 | Sodium-dependent multivitamin transporter | Not mannose-specific |
| SLC5A7 | Choline transporter | Not mannose-specific |
| SLC5A3 | Sodium/myo-inositol cotransporter | Not mannose-specific |
| SLC5A13 | Sodium-dependent glucose transporter | Potential mannose transport |
| SLC5A14 | Sodium-dependent glucose transporter | Potential mannose transport |
| SLC5A15 | Sodium-dependent glucose transporter | Potential mannose transport |
| SLC5A16 | Sodium-dependent glucose transporter | Potential mannose transport |
| SLC5A17 | Sodium-dependent glucose transporter | Potential mannose transport |
| SLC5A18 | Sodium-dependent glucose transporter | Potential mannose transport |
How Is mannose:sodium symporter activity Regulated?
The activity of mannose:sodium symporters is regulated at multiple levels. Transcriptional regulation of SLC5A genes can alter transporter abundance in response to dietary and hormonal signals. Post-translational modifications and membrane trafficking also modulate transport activity. Additionally, the sodium gradient maintained by Na+/K+-ATPase is essential for driving mannose uptake, and changes in cellular energy status can indirectly affect transport.
mannose:sodium symporter activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SLC5A2 | Diabetes mellitus | Knockout mouse, SGLT2 inhibitor treatment |
| SLC5A10 | Mannose transport disorders | Knockout cell lines, transport assays |
| SLC5A1 | Glucose-galactose malabsorption | Patient-derived organoids, CRISPR knock-in |
| SLC5A4 | Glucose sensing | Overexpression in neuroendocrine cells |
| SLC5A9 | Fructose intolerance | Knockout zebrafish, metabolic profiling |
Metabolic Disorders
Altered mannose transport has been linked to diabetes and metabolic syndrome. SGLT2 inhibitors, which target sodium-glucose cotransport, also affect mannose handling, suggesting a role in glucose homeostasis.
Neurological Disorders
Sodium oligomannate, a mannose-derived drug, has been shown to activate enteroendocrine-vagal afferent pathways in Alzheimer's disease models, indicating a connection between mannose transport and neurodegeneration.
Cancer
Mannose metabolism is altered in cancer cells, and mannose transport may influence tumor growth and glycosylation patterns. However, direct evidence for mannose:sodium symporter involvement in cancer is limited.
From mannose:sodium symporter activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does SLC5A10 mediate mannose transport in kidney? | SLC5A10 knockout HEK293 cells |
| What is the role of SGLT1 in intestinal mannose absorption? | SLC5A1 knockout mouse |
| Can point mutations alter mannose selectivity? | CRISPR point mutation in SLC5A10 |
| How does mannose transport affect Alzheimer's pathology? | APP/PS1 mouse treated with sodium oligomannate |
| Is SGLT2 involved in mannose reabsorption? | SGLT2 knockout rat |
| Can overexpression of SGLT5 increase mannose uptake? | SLC5A10 overexpression in CHO cells |
How to Study the mannose:sodium symporter activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radiolabeled uptake | Transport rate and substrate specificity | Mannose uptake in transfected cells |
| Patch-clamp | Sodium currents coupled to transport | Electrogenic transport in oocytes |
| Cryo-EM | 3D structure of transporter | Substrate binding site analysis |
| CRISPR knockout screen | Genes affecting mannose transport | Identify novel regulators |
| RNA-seq | Expression of SLC5A genes | Tissue-specific expression profiling |
| Proteomics | Protein interactions and modifications | Identify regulatory partners |
| Metabolic flux analysis | Mannose metabolism | Glycosylation studies |
| Immunofluorescence | Subcellular localization | Membrane trafficking |
Transport Assays
Radiolabeled or fluorescent mannose uptake assays in cell lines expressing candidate transporters are used to measure transport activity and kinetics.
Electrophysiology
Patch-clamp and two-electrode voltage clamp in Xenopus oocytes can measure sodium-coupled currents induced by mannose, providing real-time kinetics.
Structural Biology
Cryo-EM and X-ray crystallography of SGLT homologs reveal substrate binding sites and conformational changes during transport.
CRISPR Screening
Genome-wide CRISPR knockout screens can identify genes required for mannose transport and metabolism in various cell types.
How CRISPR Can Be Used to Study GO:0140929 mannose:sodium symporter activity
Knockout
CRISPR knockout of SLC5A genes in cell lines or animal models can abolish mannose transport, allowing assessment of its physiological role. For example, SLC5A10 knockout cells show reduced mannose uptake.
Point Mutation
Introducing point mutations in the substrate binding pocket of SLC5A transporters can alter mannose selectivity and affinity, helping to map key residues.
Knock-in
Knock-in of tagged versions of SLC5A transporters (e.g., GFP) enables live-cell imaging and proteomic analysis of mannose transport dynamics.
Overexpression
Overexpression of SLC5A10 or other candidates in heterologous systems increases mannose uptake, facilitating kinetic studies and drug screening.
How EDITGENE Supports mannose:sodium symporter activity Research
Researchers studying mannose:sodium symporter activity-related genes often need to determine whether a candidate gene is causally involved in mannose transport, metabolic regulation, or disease. EDITGENE provides comprehensive CRISPR-based services to create precise cellular and animal models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for mannose:sodium symporter activity research.
Frequently Asked Questions About mannose:sodium symporter activity
What is mannose:sodium symporter activity?
It is a molecular function (GO:0140929) that enables the sodium-coupled transport of D-mannose across membranes, as defined by the reaction D-mannose(out) + Na+(out) = D-mannose(in) + Na+(in).
What genes are involved in mannose:sodium symporter activity?
Genes in the SLC5A family, such as SLC5A1, SLC5A2, SLC5A10, and others, encode proteins that can exhibit this activity.
Which transporter has the highest selectivity for mannose?
SGLT5 (SLC5A10) shows high selectivity for mannose and fructose.
How is mannose:sodium symporter activity measured?
Common methods include radiolabeled mannose uptake assays, electrophysiology, and structural biology techniques.
Is mannose:sodium symporter activity linked to diseases?
Yes, it has been implicated in diabetes, metabolic disorders, and Alzheimer's disease through studies on SGLT inhibitors and sodium oligomannate.
What is the role of sodium in mannose transport?
Sodium provides the driving force for mannose uptake by moving down its electrochemical gradient, coupled to mannose transport.
Can CRISPR be used to study mannose:sodium symporter activity?
Yes, CRISPR knockout, point mutation, and knock-in models are powerful tools to dissect the function of SLC5A transporters.
What are the symptoms of defective mannose transport?
Defects in sugar transport can lead to metabolic imbalances, but specific symptoms depend on the transporter and tissue affected.
How does sodium oligomannate affect mannose transport?
Sodium oligomannate can activate enteroendocrine-vagal afferent pathways, potentially involving mannose transport mechanisms.
What model organisms are used to study mannose:sodium symporters?
Xenopus oocytes, HEK293 cells, and knockout mice are commonly used.
Conclusion
Mannose:sodium symporter activity (GO:0140929) is a fundamental molecular function that mediates sodium-coupled mannose transport, with critical roles in nutrient absorption, metabolism, and disease. Understanding its mechanisms through structural and functional studies, as well as CRISPR-based models, can reveal new therapeutic targets for metabolic and neurological disorders. Continued research into the SLC5A family will further illuminate the physiological and pathological significance of mannose transport.
References
- 1. Jeckelmann JM et al.. 2020. Transporters of glucose and other carbohydrates in bacteria.. Pflugers Arch 472(9):1129-1153 PMID: 32372286
- 2. Ghezzi C et al.. 2014. Fingerprints of hSGLT5 sugar and cation selectivity.. Am J Physiol Cell Physiol 306(9):C864-70 PMID: 24573086
- 3. Gong HS et al.. 2024. Sodium oligomannate activates the enteroendocrine-vagal afferent pathways in APP/PS1 mice.. Acta Pharmacol Sin 45(9):1821-1831 PMID: 38702501
- 4. Axon AT et al.. 1975. The exsorption characteristics of various sugars.. Gut 16(2):99-104 PMID: 1126665
- 5. Kamitori K et al.. 2022. Structural Basis of the Selective Sugar Transport in Sodium-Glucose Cotransporters.. J Mol Biol 434(5):167464 PMID: 35077764
