GO:0005287 high-affinity basic amino acid transmembrane transporter activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0005287 describes high-affinity transport of basic amino acids (arginine, lysine, ornithine) across membranes, enabling cells to scavenge these charged solutes even at very low extracellular concentrations.
• The term is a molecular_function in the Gene Ontology and is distinct from low-affinity or acidic/neutral amino acid transport activities.
• High-affinity basic amino acid transporters are found across evolution, from parasitic protozoa such as Leishmania donovani to human cells, where they support nutrient uptake and nitrogen metabolism.
• Several transporters with this activity function as heterodimers, for example y+LAT1 associated with 4F2hc, linking the activity to cystinuria and lysinuric protein intolerance.
• Studying GO:0005287 requires transport assays, electrophysiology, and genetic models because affinity is defined kinetically rather than by sequence alone.
• CRISPR knockout, point-mutation, knock-in, and overexpression models allow causal testing of candidate transporters and their disease variants.
Description
GO:0005287, high-affinity basic amino acid transmembrane transporter activity, is a Gene Ontology molecular_function term that captures the ability of a membrane protein to move basic amino acids such as arginine and lysine from one side of a membrane to the other with high affinity, meaning the transporter can bind its substrate even when it is present only at very low concentrations. This activity is central to nitrogen metabolism, protein synthesis, and cell signaling because basic amino acids are charged, hydrophilic molecules that cannot freely diffuse across lipid bilayers. Researchers annotate this term when a transporter shows saturable, high-affinity uptake of basic amino acids in functional assays, often in heterologous expression systems. The term is mechanistically important because affinity determines how effectively a cell competes for scarce nutrients in environments such as host tissues or soil. In humans, defects in transporters carrying this activity are linked to inherited disorders of amino acid reabsorption, including cystinuria and lysinuric protein intolerance. In protozoan parasites, high-affinity arginine transporters are proposed as drug targets because they are essential for survival in the host. Thus GO:0005287 provides a precise vocabulary for comparing transport mechanisms across species and for interpreting genetic variants that alter substrate recognition.
high-affinity basic amino acid transmembrane transporter activity At A Glance
| GO ID | GO:0005287 |
|---|---|
| GO term | high-affinity basic amino acid transmembrane transporter activity |
| Ontology | molecular_function |
| Synonym | high affinity basic amino acid transmembrane transporter activity; high-affinity basic amino acid transporter activity |
| Major function | High-affinity transfer of basic amino acids across a membrane |
| Substrate class | Basic amino acids such as arginine and lysine |
| Affinity property | Binds substrate at very low concentrations |
| Cellular context | Plasma membrane and intracellular membranes of cells and organelles |
| Related disease examples | Cystinuria and lysinuric protein intolerance |
What Is GO:0005287?
In simple terms, GO:0005287 means a protein can grab basic amino acids from outside a membrane and carry them inside, even when those amino acids are extremely scarce. The QuickGO definition states that this activity enables the transfer of basic amino acids from one side of a membrane to the other, where basic amino acids are those with a pH above 7, and high-affinity transport means the transporter binds the solute even at very low concentrations. This distinguishes it from low-affinity transporters that require higher substrate levels and from transporters specific for acidic or neutral amino acids.
Why Is high-affinity basic amino acid transmembrane transporter activity Important in Cell Biology?
GO:0005287 matters because basic amino acids are essential building blocks and signaling molecules, and their uptake cannot occur by simple diffusion; high-affinity transporters therefore determine whether cells can acquire enough arginine and lysine from nutrient-poor environments. This activity is also a point of vulnerability in pathogens and a source of inherited human disease when transporter genes are mutated.
• Enables scavenging of basic amino acids at very low environmental concentrations.
• Supports protein synthesis and nitrogen metabolism in diverse organisms.
• Contributes to host-pathogen interactions in parasitic protozoa.
• Underlies inherited disorders of renal and intestinal amino acid transport.
• Provides a kinetic signature for classifying transporter families.
• Helps interpret missense variants that alter substrate affinity.
• Guides drug discovery targeting nutrient uptake in parasites.
• Links membrane transport to metabolic and signaling pathways.
Molecular Mechanism of high-affinity basic amino acid transmembrane transporter activity
Substrate recognition and binding
In simple terms: The transporter has a pocket that fits basic amino acids tightly, so it can catch them even when they are rare.
High-affinity basic amino acid transporters recognize the positively charged side chains of arginine and lysine through acidic and aromatic residues in their transmembrane domains, forming a binding site that achieves low micromolar or submicromolar affinity. In the Leishmania donovani arginine transporter, this high-affinity binding is essential for parasite survival in the host. Charged residues in transmembrane domains can form charge pairs that promote high-affinity substrate recognition, as shown for a vesicular monoamine transporter, illustrating a general principle for amine-containing substrates.
Conformational cycle and translocation
In simple terms: After grabbing the amino acid, the transporter changes shape to move it across the membrane.
Substrate binding triggers conformational changes that alternately expose the binding site to opposite sides of the membrane, allowing the basic amino acid to be released into the cytoplasm. This alternating-access mechanism is shared with other solute carriers and can be studied by transport assays in heterologous systems. The y+L amino acid transporter-1, when associated with 4F2hc, mediates high-affinity transport of basic amino acids and is a candidate gene for lysinuric protein intolerance.
Heterodimeric assembly and partner proteins
In simple terms: Some transporters need a partner protein to reach the membrane and work properly.
Several high-affinity basic amino acid transporters function as heterodimers, such as y+LAT1 with 4F2hc, and a b(0,+)-like transporter that partners with 4F2hc instead of rBAT, representing a new candidate gene for cystinuria. The partner protein is required for surface expression and transport activity, so the activity annotated as GO:0005287 depends on both subunits.
Energetics and regulation
In simple terms: The transporter uses existing ion gradients or ATP to power uptake, and its activity can be tuned by the cell.
High-affinity basic amino acid transport can be driven by ion gradients or ATP hydrolysis depending on the transporter family; ABC-type amino acid uptake transporters in Anabaena sp. strain PCC 7120 share an ATPase subunit and are expressed in vegetative cells and heterocysts, showing that high-affinity uptake can be energetically coupled to ATP. Regulation of transporter abundance and localization allows cells to adjust uptake to nutrient availability, although the precise signals vary by organism.
Key Genes Involved in GO:0005287 high-affinity basic amino acid transmembrane transporter activity
The following genes and proteins have been experimentally linked to high-affinity basic amino acid transmembrane transporter activity or to the transport of basic amino acids with high affinity.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SLC7A7 (y+LAT1) | High-affinity basic amino acid transport when associated with 4F2hc | Candidate gene for lysinuric protein intolerance |
| SLC3A2 (4F2hc) | Partner subunit for y+LAT1 and related transporters | Required for surface expression and transport activity |
| SLC7A9 | b(0,+)-like amino acid transporter functioning with 4F2hc | New candidate gene for cystinuria |
| SLC3A1 (rBAT) | Partner for cystine and basic amino acid transporters | Contrasts with 4F2hc-dependent transporters |
| Leishmania donovani arginine transporter | Novel high-affinity arginine transporter | Parasite nutrient uptake and drug target |
| Anabaena Bgt | ABC-type amino acid uptake transporter | High-affinity uptake in cyanobacteria |
| Anabaena N-II | ABC-type amino acid uptake transporter sharing an ATPase subunit with Bgt | Nutrient acquisition in vegetative cells and heterocysts |
| VMAT (vesicular monoamine transporter) | Charged residues promote high-affinity substrate recognition | Model for charge-pair substrate binding |
| Creatine transporter | High-affinity creatine transport | Reappraisal of transporter classification |
| L-type calcium channel alpha1 subunit | High-affinity phenylalkylamine block determinants | Model for high-affinity drug binding in transmembrane segments |
| FKBP8 | Lysosomal degradation of viral M2 protein | Example of high-affinity interactions in membrane protein turnover |
| SLC7 family members | Amino acid transport across membranes | Broad family context for basic amino acid transporters |
| 4F2hc-associated transporters | Heterodimeric amino acid transport | Mechanistic and disease relevance |
| rBAT-associated transporters | Cystine and basic amino acid transport | Cystinuria candidate pathways |
| Parasite amino acid transporters | High-affinity uptake of basic amino acids | Targets for antiparasitic strategies |
| Cyanobacterial ABC transporters | ATP-dependent amino acid uptake | Model for energetic coupling |
How Is high-affinity basic amino acid transmembrane transporter activity Regulated?
Regulation of high-affinity basic amino acid transmembrane transporter activity occurs at multiple levels. In heterodimeric transporters, the partner subunit controls trafficking to the plasma membrane, so changes in partner expression directly alter transport capacity. In cyanobacteria, ABC-type amino acid uptake transporters share an ATPase subunit and are expressed in vegetative cells and heterocysts, indicating developmental and energetic regulation of high-affinity uptake. In parasites, high-affinity arginine transport is linked to survival in the host, suggesting that transporter expression is tuned to host nutrient levels. Although mechanistic details differ across systems, the common theme is that cells adjust transporter abundance and assembly to match nutrient availability and metabolic demand.
high-affinity basic amino acid transmembrane transporter activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SLC7A7 | Lysinuric protein intolerance | Knockout or point-mutation cell model with transport assay |
| SLC7A9 | Cystinuria | Knock-in of patient variants in renal epithelial cells |
| Leishmania arginine transporter | Parasitic infection | Parasite knockout and uptake assay |
| SLC3A2 | Amino acid transport defects | Overexpression and knockdown in mammalian cells |
| Anabaena Bgt/N-II | Cyanobacterial nutrient uptake | Deletion mutants and ATPase coupling assays |
Lysinuric protein intolerance
Mutations in SLC7A7, which encodes y+LAT1, impair high-affinity basic amino acid transport when the transporter is associated with 4F2hc, leading to lysinuric protein intolerance. This disorder illustrates how loss of a single high-affinity transporter can disrupt systemic amino acid homeostasis.
Cystinuria
A b(0,+)-like amino acid transporter that functions as a heterodimer with 4F2hc instead of rBAT has been proposed as a new candidate gene for cystinuria, linking high-affinity basic and cystine transport to renal stone disease. This finding expanded the set of genes implicated in cystinuria beyond the classical rBAT-dependent pathway.
Parasitic infection
Leishmania donovani expresses a novel high-affinity arginine transporter that is important for parasite nutrient acquisition, making this activity a potential target for antiparasitic intervention. Blocking high-affinity basic amino acid uptake could starve the parasite of essential amino acids.
Membrane protein quality control
High-affinity interactions between membrane proteins and quality-control machinery can influence turnover, as illustrated by FKBP8-mediated lysosomal degradation of the influenza A virus M2 protein. Although not a basic amino acid transporter, this example shows how high-affinity recognition at membranes contributes to disease-relevant processes.
From high-affinity basic amino acid transmembrane transporter activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is the candidate gene required for high-affinity basic amino acid uptake? | CRISPR knockout in a cell line followed by radiolabeled uptake assay |
| Does a patient variant alter substrate affinity? | Point-mutation knock-in of the variant and kinetic transport assay |
| Can a tagged transporter be localized and purified? | Knock-in of an epitope tag and imaging or proteomics |
| Does overexpression increase transport capacity? | Overexpression of the transporter with or without its partner subunit |
| Which partner subunit is required for surface expression? | Knockout of SLC3A2 or SLC3A1 and surface biotinylation |
| Is ATP hydrolysis required for uptake? | ABC transporter deletion mutants and ATPase assays |
How to Study the high-affinity basic amino acid transmembrane transporter activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radiolabeled uptake assay | Substrate accumulation and affinity | Testing candidate transporters |
| Patch-clamp electrophysiology | Substrate-induced currents and stoichiometry | Electrogenic transporters |
| Surface biotinylation | Plasma membrane expression | Partner subunit dependence |
| Co-immunoprecipitation | Protein-protein interactions | Heterodimer assembly |
| Fluorescence microscopy | Subcellular localization | Trafficking and knock-in tags |
| ATPase assay | ATP hydrolysis coupling | ABC-type transporters |
| Site-directed mutagenesis | Residues required for high affinity | Binding pocket mapping |
| CRISPR knockout | Gene necessity | Causal testing of candidate genes |
Transport assays
Radiolabeled or fluorescent basic amino acid uptake assays in cells expressing the candidate transporter are the gold standard for measuring high-affinity transport, because they directly report substrate accumulation over time and allow determination of Km and Vmax. These assays can be performed in knockout cells to test whether the candidate gene is necessary for uptake.
Electrophysiology and flux measurements
For electrogenic transporters, patch-clamp or two-electrode voltage clamp can measure substrate-induced currents and reveal stoichiometry and voltage dependence, complementing radiotracer uptake. Such measurements help distinguish high-affinity transport from binding without translocation.
Proteomics and interactomics
Affinity purification or proximity labeling can identify partner subunits such as 4F2hc that are required for high-affinity basic amino acid transport activity. Mass spectrometry-based proteomics can also quantify surface expression changes after genetic perturbation.
Imaging and localization
Fluorescence microscopy of tagged transporters, including knock-in of epitope tags, reveals whether the protein reaches the plasma membrane or is retained intracellularly, which is critical because mislocalization abolishes transport activity. Live-cell imaging can track trafficking in response to nutrient availability.
How CRISPR Can Be Used to Study GO:0005287 high-affinity basic amino acid transmembrane transporter activity
Knockout
CRISPR knockout of a candidate transporter gene, such as SLC7A7 or SLC7A9, eliminates the protein and allows direct testing of whether high-affinity basic amino acid uptake is lost. Knockout cells can be complemented with wild-type or mutant cDNA to confirm specificity.
Point Mutation
Point mutations identified in patients can be introduced into the endogenous locus to test whether they reduce substrate affinity or surface expression, providing functional evidence for variant pathogenicity. This approach is especially useful for missense variants in SLC7A7 and SLC7A9.
Knock-in
Knock-in of epitope tags or fluorescent proteins at the endogenous locus enables localization and interaction studies without overexpression artifacts, which is important because high-affinity transport depends on proper membrane targeting. Knock-in can also be used to humanize a transporter gene in model cells.
Overexpression
Overexpression of a transporter with its partner subunit, such as y+LAT1 with 4F2hc, can increase transport capacity and facilitate biochemical assays, but results must be interpreted with care because overexpression may saturate trafficking pathways. Overexpression is often used for initial characterization before generating knockout models.
How EDITGENE Supports high-affinity basic amino acid transmembrane transporter activity Research
Researchers studying high-affinity basic amino acid transmembrane transporter activity-related genes often need to determine whether a candidate gene is causally involved in uptake, whether a patient variant alters affinity, and how the transporter is regulated in a physiological context. EDITGENE provides CRISPR-based cell models and screening services that allow these questions to be addressed with endogenous locus control and quantitative readouts.
Contact EDITGENE today to design your custom CRISPR model for high-affinity basic amino acid transmembrane transporter activity research.
Frequently Asked Questions About high-affinity basic amino acid transmembrane transporter activity
What is GO:0005287?
GO:0005287 is the Gene Ontology molecular_function term for high-affinity basic amino acid transmembrane transporter activity, which enables the transfer of basic amino acids across a membrane even at very low substrate concentrations.
What genes are involved in high-affinity basic amino acid transmembrane transporter activity?
Genes include SLC7A7 (y+LAT1), SLC7A9, SLC3A2 (4F2hc), and SLC3A1 (rBAT), as well as parasite and cyanobacterial transporters such as the Leishmania donovani arginine transporter and Anabaena Bgt/N-II.
What is the difference between high-affinity and low-affinity amino acid transport?
High-affinity transport means the transporter binds its substrate at very low concentrations, whereas low-affinity transporters require higher substrate levels; this is defined kinetically by the Km of uptake.
Which diseases are linked to high-affinity basic amino acid transporters?
Mutations in SLC7A7 cause lysinuric protein intolerance, and SLC7A9 variants have been linked to cystinuria; parasite transporters are relevant to leishmaniasis.
How do you measure high-affinity basic amino acid transport?
Radiolabeled or fluorescent uptake assays, electrophysiology, and surface biotinylation are commonly used to measure transport activity and membrane localization.
Do high-affinity basic amino acid transporters need partner proteins?
Yes, several function as heterodimers, such as y+LAT1 with 4F2hc, and the partner subunit is required for surface expression and activity.
Can CRISPR be used to study GO:0005287?
Yes, CRISPR knockout, point-mutation knock-in, and overexpression models allow causal testing of transporter genes and patient variants.
What is the role of 4F2hc in basic amino acid transport?
4F2hc (SLC3A2) is a partner subunit that associates with transporters such as y+LAT1 to enable high-affinity basic amino acid transport at the plasma membrane.
Are there high-affinity basic amino acid transporters in parasites?
Yes, Leishmania donovani expresses a novel high-affinity arginine transporter that is important for nutrient uptake and is considered a potential drug target.
What methods identify residues required for high-affinity binding?
Site-directed mutagenesis combined with transport assays and structural modeling can identify charged and aromatic residues that form the substrate binding pocket.
Conclusion
GO:0005287, high-affinity basic amino acid transmembrane transporter activity, defines a kinetically distinct class of membrane proteins that allow cells to acquire essential basic amino acids even when they are scarce. This activity is mediated by transporters such as y+LAT1 and related heterodimeric systems, with direct links to lysinuric protein intolerance and cystinuria, and it is also important in parasites and cyanobacteria. Studying this term requires functional transport assays combined with genetic models, because affinity and substrate specificity cannot be inferred from sequence alone. CRISPR-based knockout, point-mutation, knock-in, and overexpression models provide a rigorous path to test candidate genes and variants, and EDITGENE offers these services to accelerate research on basic amino acid transport.
References
- 1. Lv L et al.. 2026. FKBP8 inhibits influenza a virus infection by degrading viral M2 protein in lysosomes.. Autophagy PMID: 42212595
- 2. Speer O et al.. 2004. Creatine transporters: a reappraisal.. Mol Cell Biochem 256-257(1-2):407-24 PMID: 14977199
- 3. Shaked-Mishan P et al.. 2006. A novel high-affinity arginine transporter from the human parasitic protozoan Leishmania donovani.. Mol Microbiol 60(1):30-8 PMID: 16556218
- 4. Torrents D et al.. 1998. Identification and characterization of a membrane protein (y+L amino acid transporter-1) that associates with 4F2hc to encode the amino acid transport activity y+L. A candidate gene for lysinuric protein intolerance.. J Biol Chem 273(49):32437-45 PMID: 9829974
- 5. Merickel A et al.. 1997. Charged residues in transmembrane domains II and XI of a vesicular monoamine transporter form a charge pair that promotes high affinity substrate recognition.. J Biol Chem 272(9):5403-8 PMID: 9038139
- 6. Rajan DP et al.. 1999. Cloning and expression of a b(0,+)-like amino acid transporter functioning as a heterodimer with 4F2hc instead of rBAT. A new candidate gene for cystinuria.. J Biol Chem 274(41):29005-10 PMID: 10506149
- 7. Hockerman GH et al.. 1997. Molecular determinants of high affinity phenylalkylamine block of L-type calcium channels in transmembrane segment IIIS6 and the pore region of the alpha1 subunit.. J Biol Chem 272(30):18759-65 PMID: 9228049
- 8. Pernil R et al.. 2008. ABC-type amino acid uptake transporters Bgt and N-II of Anabaena sp. strain PCC 7120 share an ATPase subunit and are expressed in vegetative cells and heterocysts.. Mol Microbiol 67(5):1067-80 PMID: 18208492
