GO:1903401 L-lysine transmembrane transport: Amino Acid Transport Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1903401 describes the directed movement of L-lysine across a membrane, a process essential for amino acid homeostasis and cellular metabolism.
• L-lysine transport is mediated by specific membrane transporters and has been studied in intestinal and renal brush border membrane vesicles.
• Engineering amino acid transporters can enhance L-lysine production in industrial microorganisms such as Corynebacterium glutamicum.
• Conserved lysine residues in transmembrane helices are critical for the transport activity of several membrane proteins, including organic anion transporting polypeptide 1B3.
• Defects in lysine transport or related membrane proteins can contribute to metabolic disorders and diseases, though direct links to specific pathologies require further investigation.
• CRISPR-based gene editing enables functional dissection of L-lysine transporters through knockout, point mutation, knock-in, and overexpression models.
Description
L-lysine transmembrane transport (GO:1903401) is a biological process defined as the directed movement of L-lysine across a membrane. L-lysine is an essential amino acid that must be obtained from the diet in animals, and its uptake into cells is mediated by specialized transport systems located in the plasma membrane and organelle membranes. This process is fundamental for protein synthesis, energy metabolism, and cellular signaling, and its dysregulation has been implicated in various physiological and pathological states. Researchers study L-lysine transport to understand nutrient absorption, amino acid homeostasis, and the molecular mechanisms of membrane transport proteins. The process is also of industrial interest, as engineering amino acid transporters can improve L-lysine production in microbial fermentation. In this article, we provide a comprehensive overview of GO:1903401, covering its definition, key genes, regulatory mechanisms, disease associations, and experimental approaches for investigation.
L-lysine transmembrane transport At A Glance
| GO ID | GO:1903401 |
|---|---|
| GO term | L-lysine transmembrane transport |
| Ontology | biological_process |
| Synonym | None |
| Major function | Directed movement of L-lysine across a membrane |
| Related processes | Amino acid transport, nutrient uptake, protein synthesis |
| Cellular locations | Plasma membrane, organelle membranes |
| Key transporters | Members of the amino acid transporter families (e.g., SLC family) |
| Research relevance | Metabolic engineering, nutrient absorption, disease mechanisms |
What Is GO:1903401?
GO:1903401, L-lysine transmembrane transport, is the biological process by which L-lysine, the naturally occurring stereoisomer of the amino acid lysine, is moved across a lipid bilayer membrane. This directed movement can occur through passive diffusion or, more commonly, via specific transporter proteins that facilitate or actively pump L-lysine into or out of cells or organelles. The process is essential for maintaining intracellular L-lysine concentrations and for supplying this amino acid for protein synthesis and other metabolic pathways.
Why Is L-lysine transmembrane transport Important in Cell Biology?
L-lysine transmembrane transport is critical for cellular amino acid homeostasis and overall metabolism. In animals, efficient L-lysine uptake in the intestine and kidney is necessary for nutrition and nitrogen balance. In microorganisms, L-lysine transport influences the yield of industrial fermentation processes for amino acid production. Moreover, membrane transporters that mediate L-lysine movement are potential drug targets and their dysfunction may contribute to metabolic disorders. Understanding the molecular details of L-lysine transport is therefore relevant to basic cell biology, nutrition, biotechnology, and medicine.
• Essential for dietary L-lysine absorption in the intestine and reabsorption in the kidney.
• Maintains intracellular L-lysine pools required for protein synthesis and post-translational modifications.
• Influences metabolic engineering strategies for L-lysine overproduction in Corynebacterium glutamicum.
• Membrane transporters for L-lysine are potential targets for modulating amino acid availability in disease.
• Conserved lysine residues in transmembrane helices are critical for the function of many transport proteins.
• L-lysine transport is linked to the transport of other amino acids and nutrients, affecting overall metabolic balance.
• Dysregulation of amino acid transport can impact cell growth and proliferation, relevant to cancer metabolism.
• Studying L-lysine transport provides insights into the evolution and diversity of membrane transport mechanisms.
• CRISPR-based editing of transporter genes enables precise functional studies and therapeutic development.
What Happens During L-lysine transmembrane transport?
Recognition and Binding of L-lysine
In simple terms: The transporter protein recognizes and grabs L-lysine on one side of the membrane.
The first step in L-lysine transmembrane transport involves the specific recognition of L-lysine by a membrane transporter protein. This binding is typically mediated by amino acid residues within the transporter's substrate-binding pocket, which form non-covalent interactions with the amino acid's side chain and backbone. For example, in the organic anion transporting polypeptide 1B3, conserved lysine and arginine residues in transmembrane helices are essential for transport activity, highlighting the importance of electrostatic interactions in substrate recognition. Similarly, studies on rat intestinal brush border membrane vesicles have demonstrated saturable, carrier-mediated transport of L-lysine, indicating the involvement of specific transporter proteins.
Conformational Changes and Translocation
In simple terms: The transporter changes shape to move L-lysine across the membrane.
Upon binding, the transporter undergoes conformational changes that allow the substrate to be translocated across the lipid bilayer. This process often follows an alternating access mechanism, where the transporter switches between outward-facing and inward-facing states. In the case of ATP8A2, a P4-ATPase, a critical transmembrane lysine residue is involved in aminophospholipid transport, suggesting that similar mechanisms may apply to amino acid transporters. The energy for translocation can come from ATP hydrolysis, ion gradients, or the substrate's concentration gradient, depending on the transporter type.
Release of L-lysine on the Opposite Side
In simple terms: L-lysine is released inside the cell or organelle.
After translocation, the transporter releases L-lysine into the cytoplasm or organelle lumen. This release is triggered by a change in the transporter's conformation and a lower binding affinity for the substrate in the new environment. The process ensures the directed movement of L-lysine, maintaining concentration gradients across the membrane. In renal brush border membrane vesicles, L-cystine transport has been studied as a model for amino acid transport, and similar principles apply to L-lysine.
Regulation and Coupling to Other Transport Processes
In simple terms: The transport process can be turned up or down and can be linked to other molecules.
L-lysine transport is regulated at multiple levels, including transporter expression, post-translational modifications, and interaction with other proteins. For instance, myristoylation of TMEM106B by NMT1/2 regulates its trafficking and turnover, which may affect its role in lysosomal function and amino acid transport. Additionally, the transport of L-lysine can be coupled to the movement of other ions or amino acids, as seen in various solute carrier (SLC) family transporters. Understanding these regulatory mechanisms is crucial for manipulating L-lysine transport in biotechnological and therapeutic contexts.
Key Genes Involved in GO:1903401 L-lysine transmembrane transport
The following genes encode proteins that are directly or indirectly involved in L-lysine transmembrane transport, based on experimental evidence from transport assays, genetic studies, and biochemical characterization.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SLC7A1 | Cationic amino acid transporter, mediates L-lysine uptake | Studied in intestinal and renal absorption |
| SLC7A2 | Cationic amino acid transporter, transports L-lysine | Involved in macrophage function and amino acid homeostasis |
| SLC7A3 | Cationic amino acid transporter, high-affinity L-lysine transport | Expressed in brain and testis, potential role in neuronal function |
| SLC7A4 | Cationic amino acid transporter, L-lysine transport | Less characterized, may contribute to amino acid transport |
| SLC3A2 | Heavy chain of heteromeric amino acid transporters, partners with SLC7A | Essential for surface expression of L-lysine transporters |
| SLC25A15 | Mitochondrial ornithine/citrulline carrier, may transport L-lysine | Defects cause hyperornithinemia-hyperammonemia-homocitrullinuria syndrome |
| SLC25A2 | Mitochondrial ornithine/citrulline carrier, potential L-lysine transport | Involved in urea cycle and amino acid metabolism |
| ATP8A2 | P4-ATPase, aminophospholipid transporter with critical lysine residue | Model for studying lysine residues in transport |
| ABCD4 | ABC transporter, cobalamin transport, requires transmembrane helix 6 | Mutations cause cobalamin disorders, may affect amino acid transport |
| TMEM106B | Lysosomal transmembrane protein, regulated by myristoylation | Implicated in neurodegeneration, may influence amino acid transport |
| OATP1B3 | Organic anion transporting polypeptide, conserved lysine residues critical | Model for studying lysine residues in transport activity |
| NMT1 | N-myristoyltransferase, modifies TMEM106B | Regulates TMEM106B trafficking and turnover |
| NMT2 | N-myristoyltransferase, modifies TMEM106B | Regulates TMEM106B trafficking and turnover |
| Corynebacterium glutamicum lysE | L-lysine exporter | Engineered for increased L-lysine production |
| Corynebacterium glutamicum lysP | L-lysine permease | Engineered for increased L-lysine production |
| Corynebacterium glutamicum aroP | Aromatic amino acid transporter, may affect L-lysine | Target for metabolic engineering |
| Corynebacterium glutamicum NCgl1221 | Mechanosensitive channel, L-lysine secretion | Involved in L-lysine export |
How Is L-lysine transmembrane transport Regulated?
L-lysine transmembrane transport is regulated at multiple levels. Transcriptional regulation controls the expression of transporter genes in response to amino acid availability and cellular stress. Post-translational modifications, such as myristoylation of TMEM106B by NMT1/2, regulate protein trafficking and turnover, thereby influencing transport activity. Conserved lysine and arginine residues in transmembrane helices are critical for the function of transporters like OATP1B3, and mutations in these residues can alter transport kinetics. Additionally, the activity of L-lysine transporters can be modulated by interacting proteins and membrane lipid composition. In industrial microorganisms, engineering transporter expression and specificity has been used to enhance L-lysine production.
L-lysine transmembrane transport and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SLC25A15 | Hyperornithinemia-hyperammonemia-homocitrullinuria syndrome | Knockout mouse, patient-derived fibroblasts |
| TMEM106B | Frontotemporal dementia, lysosomal dysfunction | Knockout and knock-in cell lines, neuronal cultures |
| ATP8A2 | Neurological disorders, aminophospholipid transport defects | Point mutation knock-in mice, cell-based transport assays |
| OATP1B3 | Drug transport, hyperbilirubinemia | Overexpression in HEK293 cells, mutagenesis |
| SLC7A1 | Cancer cell proliferation, amino acid addiction | Knockout cancer cell lines, xenograft models |
L-lysine transport in metabolic disorders
Disruptions in amino acid transport can lead to metabolic imbalances. For example, defects in the mitochondrial ornithine/citrulline carrier SLC25A15 cause hyperornithinemia-hyperammonemia-homocitrullinuria syndrome, which affects amino acid metabolism including lysine. While direct links between L-lysine transport defects and specific diseases are still being elucidated, the importance of lysine residues in transport proteins is highlighted by studies on ATP8A2 and OATP1B3.
L-lysine transport and neurological function
The brain requires efficient amino acid transport for neurotransmitter synthesis and energy metabolism. TMEM106B, a lysosomal transmembrane protein regulated by myristoylation, has been implicated in neurodegenerative diseases such as frontotemporal dementia. Although its role in L-lysine transport is not fully defined, it may influence lysosomal amino acid homeostasis. Additionally, cationic amino acid transporters like SLC7A3 are expressed in the brain, suggesting a role in neuronal L-lysine uptake.
L-lysine transport in cancer and cell proliferation
Cancer cells often reprogram amino acid metabolism to support rapid growth. L-lysine is required for protein synthesis and may be transported by SLC7A1 and SLC7A2, which are overexpressed in some cancers. Targeting these transporters could be a therapeutic strategy, though further research is needed to establish direct links.
From L-lysine transmembrane transport-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does knockout of SLC7A1 reduce L-lysine uptake? | CRISPR knockout in HeLa or HEK293 cells |
| What is the effect of a point mutation in the substrate-binding site? | CRISPR point mutation knock-in in transporter gene |
| Can overexpression of SLC7A2 increase L-lysine transport? | Lentiviral overexpression in CHO cells |
| How does tagged SLC7A3 localize in neurons? | Knock-in of fluorescent tag (e.g., GFP) in SLC7A3 locus |
| Does TMEM106B myristoylation affect L-lysine transport? | Knockout of NMT1/2 or point mutation of myristoylation site |
| Can engineering lysE improve L-lysine production? | CRISPR interference or overexpression in C. glutamicum |
How to Study the L-lysine transmembrane transport Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Brush border membrane vesicle uptake assay | Transport rate and kinetics | Characterizing L-lysine transport in intestine/kidney |
| Heterologous expression in oocytes | Transporter activity and substrate specificity | Functional validation of candidate transporters |
| Site-directed mutagenesis | Role of specific residues in transport | Identifying critical lysine residues |
| CRISPR knockout screen | Genes required for L-lysine transport | Discovery of novel transporters |
| RNA-seq | Expression of transporter genes | Tissue-specific expression profiling |
| Proteomics | Protein abundance and modifications | Quantifying transporter levels and myristoylation |
| Metabolic flux analysis | L-lysine production and consumption rates | Optimizing industrial strains |
| Live-cell imaging | Subcellular localization of transporters | Tracking trafficking and dynamics |
Transport assays using brush border membrane vesicles
Brush border membrane vesicles isolated from intestinal or renal tissues are a classic system to study L-lysine transport. These vesicles retain the orientation and functionality of native transporters, allowing measurement of uptake kinetics, substrate specificity, and inhibition. Studies using rat intestinal and renal brush border membrane vesicles have characterized L-lysine and L-cystine transport, providing foundational data for GO:1903401.
Heterologous expression and mutagenesis
Cloning and expressing candidate transporters in cell lines such as HEK293 or Xenopus oocytes enables detailed functional analysis. Site-directed mutagenesis of conserved residues, such as lysine and arginine in transmembrane helices, can reveal their roles in transport activity, as demonstrated for OATP1B3 and ATP8A2.
CRISPR-based genetic screens
Genome-wide CRISPR knockout or activation screens can identify genes that regulate L-lysine transport. By selecting cells based on L-lysine uptake or deprivation, researchers can uncover novel transporters and regulatory pathways. This approach is particularly powerful for identifying redundant or non-canonical transport mechanisms.
Metabolic engineering and flux analysis
In industrial microbiology, engineering amino acid transporters can redirect metabolic flux toward L-lysine production. Techniques such as promoter engineering, gene knockout, and heterologous expression are used to optimize transport. For example, engineering amino acid transporters in Corynebacterium glutamicum increased L-lysine production.
How CRISPR Can Be Used to Study GO:1903401 L-lysine transmembrane transport
Knockout
CRISPR knockout of candidate L-lysine transporter genes (e.g., SLC7A1, SLC7A2) can abolish or reduce L-lysine uptake, providing direct evidence of their function. Knockout cell lines are also useful for identifying compensatory transporters through genome-wide screens. In metabolic engineering, knockout of competing transporters can redirect flux toward L-lysine production.
Point Mutation
CRISPR point mutation allows precise alteration of single amino acids, such as conserved lysine residues in transmembrane helices, to test their role in transport activity. This approach has been used to study OATP1B3 and ATP8A2, revealing critical residues for substrate binding and translocation. Point mutations can also mimic disease-associated variants.
Knock-in
Knock-in of epitope tags (e.g., GFP, HA) or reporter genes into endogenous transporter loci enables real-time tracking of protein expression, localization, and dynamics. For example, tagging TMEM106B can reveal its trafficking and turnover regulation by myristoylation. Knock-in of disease mutations can create isogenic models for studying transport defects.
Overexpression
CRISPR activation (CRISPRa) or lentiviral overexpression can increase the expression of L-lysine transporters to study their capacity and regulation. Overexpression of lysE in Corynebacterium glutamicum enhanced L-lysine export and production. In mammalian cells, overexpression can help characterize transport kinetics and substrate specificity.
How EDITGENE Supports L-lysine transmembrane transport Research
Researchers studying L-lysine transmembrane transport-related genes often need to determine whether a candidate gene is causally involved in L-lysine uptake, efflux, or regulation. Establishing causality requires precise genetic manipulation, which is where EDITGENE's CRISPR services can accelerate discovery.
Contact EDITGENE today to design your custom CRISPR model for L-lysine transmembrane transport research.
Frequently Asked Questions About L-lysine transmembrane transport
What is L-lysine transmembrane transport?
L-lysine transmembrane transport (GO:1903401) is the directed movement of the amino acid L-lysine across a biological membrane, typically mediated by specific transporter proteins.
What genes are involved in L-lysine transmembrane transport?
Genes encoding cationic amino acid transporters such as SLC7A1, SLC7A2, and SLC7A3, as well as mitochondrial carriers like SLC25A15, are involved in L-lysine transport.
How is L-lysine transported across the membrane?
L-lysine is transported by membrane proteins that undergo conformational changes to move the amino acid from one side of the membrane to the other, often using energy from ATP or ion gradients.
What is the role of L-lysine transport in bacteria?
In bacteria like Corynebacterium glutamicum, L-lysine transport is important for amino acid production and can be engineered to increase industrial yields.
Which diseases are associated with defects in L-lysine transport?
Defects in amino acid transporters can cause metabolic disorders; for example, mutations in SLC25A15 cause hyperornithinemia-hyperammonemia-homocitrullinuria syndrome, which affects amino acid metabolism.
How can I study L-lysine transmembrane transport in the lab?
Common methods include brush border membrane vesicle uptake assays, heterologous expression in oocytes or cell lines, and CRISPR-based genetic screens.
What is the function of lysine residues in transport proteins?
Conserved lysine residues in transmembrane helices are often critical for substrate binding and transport activity, as shown for OATP1B3 and ATP8A2.
Can CRISPR be used to study L-lysine transport?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models enable precise functional dissection of L-lysine transporters and their regulators.
What is the clinical relevance of L-lysine transport?
L-lysine transport is relevant to nutrition, metabolic disorders, and cancer metabolism, and transporters are potential drug targets.
How does myristoylation affect L-lysine transport?
Myristoylation of proteins like TMEM106B by NMT1/2 regulates their trafficking and turnover, which may influence lysosomal amino acid transport.
Conclusion
L-lysine transmembrane transport (GO:1903401) is a fundamental biological process that ensures the proper distribution of L-lysine across cellular membranes. It is mediated by a diverse array of transporters and is critical for nutrition, metabolism, and cellular function. Dysregulation of this process has been linked to metabolic disorders and other diseases, and it is a target for metabolic engineering. Advances in CRISPR gene editing and functional genomics are accelerating our understanding of the molecular mechanisms and regulatory networks underlying L-lysine transport. EDITGENE provides comprehensive CRISPR services to support researchers in dissecting the roles of specific transporters and developing new therapeutic strategies.
References
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