GO:1905647 proline import across plasma membrane: Transport Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1905647 (proline import across plasma membrane) describes the directed movement of proline from outside a cell into the cytoplasmic compartment.
• Proline import is mediated by membrane transporters, including members of the amino acid transporter families such as SLC36 and SLC38, which can act as antiporters with asymmetric substrate specificity.
• In plants, proline transporters such as LeProT1 transport proline, glycine betaine, and GABA, highlighting a role in stress responses and pollen biology.
• Zinc transporters of the ZIP and ZnT families are structurally and functionally related to amino acid transporters and influence immune cell function, providing comparative insights into transport mechanisms.
• Proline import is relevant to gut health and amino acid metabolism, as shown in piglets where N-acyl-homoserine lactones alter intestinal epithelial barrier function and amino acid metabolism.
• CRISPR-based models (knockout, point mutation, knock-in, overexpression) enable causal dissection of proline transporter genes in health and disease.
Description
Proline import across plasma membrane (GO:1905647) is a biological process defined as the directed movement of proline from outside of a cell into the cytoplasmic compartment. Proline is a unique amino acid that serves as a building block for proteins, a compatible osmolyte, and a signaling molecule. Its uptake is mediated by specific membrane transporters that ensure adequate intracellular proline levels for metabolism and stress responses. Understanding this process is critical because dysregulated proline transport has been linked to altered amino acid metabolism and cellular dysfunction in various organisms. Researchers study proline import to elucidate mechanisms of nutrient sensing, osmotic stress adaptation, and metabolic reprogramming in diseases such as cancer and neurodegeneration. The process is also relevant in plant biology, where proline transporters contribute to pollen development and drought tolerance. This article synthesizes current knowledge on the genes, functions, and research methods associated with GO:1905647, providing a resource for experimental design and therapeutic targeting.
proline import across plasma membrane At A Glance
| GO ID | GO:1905647 |
|---|---|
| GO term | proline import across plasma membrane |
| Ontology | biological_process |
| Synonym | proline import into cell |
| Major function | Transport of proline from the extracellular space into the cytoplasm |
| Cellular location | Plasma membrane |
| Substrates | Proline (and in some cases glycine betaine, GABA) |
| Related transporters | Amino acid antiporters, SLC36/SLC38 families |
| Physiological context | Amino acid metabolism, osmotic stress, gut health |
What Is GO:1905647?
GO:1905647, proline import across plasma membrane, is the directed movement of proline from outside of a cell into the cytoplasmic compartment. This process requires the function of transporter proteins that facilitate the passage of proline across the lipid bilayer, often against a concentration gradient, and is distinct from proline biosynthesis or intracellular transport.
Why Is proline import across plasma membrane Important in Cell Biology?
Proline import across plasma membrane is essential for maintaining intracellular proline pools that support protein synthesis, cellular osmoprotection, and metabolic signaling. Defects in proline transport can disrupt amino acid homeostasis and contribute to disease states, including intestinal barrier dysfunction and metabolic disorders. In plants, proline transporters are critical for pollen fertility and stress tolerance, underscoring the evolutionary conservation of this process. Moreover, amino acid antiporters exhibit asymmetric substrate specificity, which influences transport efficiency and cellular physiology. Studying GO:1905647 provides insights into nutrient acquisition, stress responses, and potential therapeutic targets for diseases linked to amino acid dysregulation.
• Maintains intracellular proline levels for protein synthesis and cell growth.
• Supports osmotic stress responses by importing proline as a compatible osmolyte.
• Influences gut health and intestinal epithelial barrier function.
• Contributes to plant pollen development and drought tolerance.
• Provides a model for understanding amino acid antiporter specificity.
• Links to immune cell function via related zinc transporters.
• Potential target for cancer metabolism and neurodegeneration research.
• Enables CRISPR-based functional studies of transporter genes.
• Relevant to metabolic reprogramming in low-birth-weight piglets.
• Highlights evolutionary conservation of nutrient transport mechanisms.
What Happens During proline import across plasma membrane?
Recognition and Binding of Proline
In simple terms: The transporter protein on the cell surface recognizes and grabs proline from outside the cell.
The process begins when a plasma membrane transporter binds extracellular proline with high specificity. Amino acid antiporters, such as those in the SLC36 and SLC38 families, exhibit asymmetric substrate specificity, meaning they preferentially bind proline on one side of the membrane. This binding is the first committed step and determines the selectivity of the transport process.
Conformational Change and Translocation
In simple terms: The transporter changes shape to move proline across the membrane into the cell.
Upon proline binding, the transporter undergoes a conformational change that translocates the substrate across the lipid bilayer. This step may be coupled to the movement of another solute (antiport) or driven by electrochemical gradients. The mechanism ensures directed movement of proline from outside to the cytoplasmic compartment, as defined by GO:1905647.
Release of Proline into the Cytoplasm
In simple terms: Once inside, the transporter releases proline so it can be used by the cell.
After translocation, proline is released into the cytoplasm due to a lower binding affinity on the intracellular side. This release is essential for maintaining a concentration gradient and for subsequent metabolic utilization. In plant cells, transporters like LeProT1 also transport glycine betaine and GABA, indicating broader substrate handling.
Regulation and Integration with Cellular Metabolism
In simple terms: The cell adjusts proline import based on its needs and external signals.
Proline import is regulated by nutrient availability, osmotic stress, and hormonal signals. For example, in piglets, N-acyl-homoserine lactones alter intestinal amino acid metabolism, potentially affecting proline transport. This integration ensures that proline uptake matches cellular demands for protein synthesis and stress protection.
Key Genes Involved in GO:1905647 proline import across plasma membrane
The following genes and proteins are implicated in proline import across plasma membrane or related transport processes, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SLC36A1 | Proton-coupled amino acid transporter; transports proline and other small amino acids | Studied for intestinal absorption and drug transport |
| SLC38A2 | Sodium-coupled neutral amino acid transporter; can transport proline | Implicated in cell growth and mTOR signaling |
| LeProT1 | Plant proline transporter; also transports glycine betaine and GABA | Model for stress tolerance and pollen development |
| ZIP transporters | Zinc transporters with structural similarity to amino acid transporters | Comparative studies in immune cells |
| ZnT transporters | Zinc efflux transporters; related to amino acid transport families | Immune cell function and metal homeostasis |
| OsPIP2;2 | Aquaporin in rice; water transport facilitator | Drought tolerance; not directly proline transport but related stress responses |
| Mia40 | Mitochondrial import receptor; not proline-specific | Protein import mechanisms; provides contrast to small molecule transport |
| prepro-alpha-factor | Yeast signal sequence; affects membrane translocation | Model for signal sequence function in transport |
| SLC7A5 | L-type amino acid transporter; antiporter for large neutral amino acids | Cancer metabolism and drug targeting |
| SLC3A2 | Heavy chain of amino acid transporters; partners with SLC7A5 | Cell surface transport regulation |
| SLC1A5 | Neutral amino acid transporter; can transport proline | Glutamine and proline metabolism in cancer |
| PAT1 | Proton-coupled amino acid transporter; transports proline | Intestinal and renal amino acid absorption |
| SNAT2 | Sodium-coupled neutral amino acid transporter; proline transport | Nutrient sensing and cell growth |
| LAT1 | L-type amino acid transporter; transports large amino acids | Blood-brain barrier and cancer |
| CAT-1 | Cationic amino acid transporter; not proline-specific | Arginine and lysine transport; comparative |
| EAATs | Excitatory amino acid transporters; primarily glutamate | Neurotransmission; not proline-specific |
| GABA transporters | Transport GABA; may overlap with proline transport in plants | Plant stress responses |
| Betaine transporters | Transport glycine betaine; related to proline transport in plants | Osmotic stress tolerance |
How Is proline import across plasma membrane Regulated?
Proline import across plasma membrane is regulated at multiple levels. Transcriptional regulation of transporter genes responds to amino acid availability and stress signals. For instance, in piglets, N-acyl-homoserine lactones modulate intestinal amino acid metabolism, suggesting regulation by microbial metabolites. Post-translational modifications, such as phosphorylation, can alter transporter activity and trafficking. Additionally, the asymmetric substrate specificity of antiporters like SLC7A5 and SLC3A2 influences transport direction and efficiency. In plants, proline transport is regulated during pollen development and drought stress, with LeProT1 expression peaking under stress conditions. These regulatory mechanisms ensure that proline import is tightly coupled to cellular needs.
proline import across plasma membrane and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SLC1A5 | Cancer metabolism | Knockout in cancer cell lines; proliferation assays |
| SLC7A5 | Cancer and immune disorders | Point mutation to alter substrate specificity; transport assays |
| LeProT1 | Plant stress tolerance | Knock-in in Arabidopsis; drought stress tests |
| SLC36A1 | Gut health and absorption | Overexpression in intestinal epithelial cells; barrier function assays |
| ZIP transporters | Immune cell function | Knockout in immune cells; zinc and amino acid transport |
Proline Transport in Cancer Metabolism
Altered amino acid transport is a hallmark of cancer. Proline import supports protein synthesis and metabolic reprogramming in tumor cells. Transporters such as SLC1A5 and SLC7A5 are overexpressed in various cancers and contribute to glutamine and proline uptake, fueling growth. Targeting these transporters is a potential therapeutic strategy.
Intestinal Barrier Dysfunction and Gut Health
Proline import is critical for intestinal epithelial cells, which rely on amino acid uptake for barrier integrity. In low-birth-weight piglets, N-acyl-homoserine lactones alter intestinal epithelial cell barrier function and amino acid metabolism, including proline. Dysregulated proline transport may contribute to gut inflammation and permeability disorders.
Neurodegeneration and Amino Acid Transport
Proline and related amino acids act as neurotransmitters or modulators. Transporters like SLC36A1 are expressed in the brain, and their dysfunction may affect neuronal function. While direct links to neurodegeneration are not fully established, amino acid transport defects are implicated in neurological disorders.
Plant Stress and Agricultural Relevance
In plants, proline transport is vital for osmotic stress tolerance and pollen fertility. LeProT1 transports proline and glycine betaine, contributing to drought tolerance. Understanding these mechanisms can inform crop improvement strategies.
From proline import across plasma membrane-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does knockout of SLC36A1 affect proline import? | CRISPR knockout in HEK293 or intestinal cells |
| Does a point mutation in SLC7A5 alter substrate specificity? | CRISPR point mutation followed by transport assays |
| Can overexpression of LeProT1 enhance drought tolerance? | Knock-in or overexpression in plant models |
| How does tagged SLC38A2 localize during proline transport? | Tagged knock-in with fluorescent protein |
| Does SLC1A5 knockout reduce cancer cell growth? | CRISPR knockout in cancer cell lines |
| What is the role of ZIP transporters in immune cells? | Knockout or overexpression in immune cell lines |
How to Study the proline import across plasma membrane Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radiolabeled proline uptake | Rate of proline import | Kinetic analysis of transporters |
| CRISPR knockout screen | Genes required for proline import | Identification of novel transporters |
| RNA-seq | Expression of transporter genes | Transcriptional regulation studies |
| Proteomics | Protein interactions and modifications | Regulatory network discovery |
| Fluorescence microscopy | Subcellular localization | Trafficking and membrane targeting |
| Patch-clamp electrophysiology | Transporter currents | Electrogenic transport mechanisms |
| Site-directed mutagenesis | Functional residues | Structure-function analysis |
Transport Assays with Radiolabeled Proline
Radiolabeled proline uptake assays measure the rate of proline import in cells expressing specific transporters. This method is quantitative and can be used to assess kinetic parameters and inhibitor effects.
CRISPR Screening for Transporters
Genome-wide CRISPR knockout screens can identify genes required for proline import. Cells are cultured with limited proline, and sgRNAs targeting transporters are enriched or depleted based on survival.
Proteomics and Interactomics
Mass spectrometry-based proteomics can identify proteins associated with proline transporters and post-translational modifications. This approach reveals regulatory networks and interaction partners.
Imaging of Transporter Localization
Fluorescence microscopy of tagged transporters (e.g., GFP fusion) visualizes plasma membrane localization and trafficking dynamics in live cells.
How CRISPR Can Be Used to Study GO:1905647 proline import across plasma membrane
Knockout
CRISPR knockout of proline transporter genes (e.g., SLC36A1, SLC7A5) abolishes proline import, allowing researchers to study downstream effects on cell growth, metabolism, and stress responses. Knockout models are essential for validating gene function.
Point Mutation
CRISPR point mutations can alter specific residues in transporter proteins to dissect substrate binding and specificity. For example, mutating residues in the binding pocket of SLC7A5 can reveal determinants of asymmetric substrate specificity.
Knock-in
Knock-in of tagged transporters (e.g., GFP or HA) enables visualization and purification of transporter complexes. This approach is useful for studying localization and interaction partners in native contexts.
Overexpression
CRISPR activation (CRISPRa) or cDNA overexpression can increase proline transporter levels, enhancing proline import. This is useful for gain-of-function studies and for producing large quantities of transporter for biochemical assays.
How EDITGENE Supports proline import across plasma membrane Research
Researchers studying proline import across plasma membrane-related genes often need to determine whether a candidate gene is causally involved in transport, metabolism, or disease. EDITGENE provides comprehensive CRISPR services to accelerate this discovery process.
Contact EDITGENE today to design your custom CRISPR model for proline import across plasma membrane research.
Frequently Asked Questions About proline import across plasma membrane
What is proline import across plasma membrane?
It is the biological process (GO:1905647) of moving proline from outside a cell into the cytoplasm, mediated by specific transporters.
What genes are involved in proline import across plasma membrane?
Genes include SLC36A1, SLC38A2, SLC7A5, SLC1A5, and plant LeProT1, among others.
How is proline import regulated?
It is regulated by nutrient availability, stress signals, and post-translational modifications of transporters.
What diseases are linked to proline transport?
Cancer metabolism, gut barrier dysfunction, and potentially neurodegeneration.
What methods study proline import?
Radiolabeled uptake assays, CRISPR screens, proteomics, and imaging.
Can CRISPR be used to study proline transporters?
Yes, knockout, point mutation, knock-in, and overexpression models enable functional studies.
What is the role of proline import in plants?
It supports osmotic stress tolerance and pollen development, as shown for LeProT1.
Are there drugs targeting proline transporters?
Some inhibitors of amino acid transporters are under investigation, but none are clinically approved for proline transport specifically.
How does proline import affect gut health?
It provides amino acids for intestinal epithelial cells; disruption may impair barrier function.
What is the GO ID for proline import across plasma membrane?
GO:1905647.
Conclusion
Proline import across plasma membrane (GO:1905647) is a fundamental biological process that maintains intracellular proline pools for protein synthesis, osmotic balance, and metabolic signaling. Research has identified key transporters and their roles in health and disease, from cancer metabolism to plant stress tolerance. CRISPR-based models offer powerful tools to dissect the genetic and mechanistic basis of proline transport. Continued investigation will uncover therapeutic opportunities and deepen our understanding of amino acid homeostasis.
References
- 1. Gauthier-Coles G et al.. 2023. Do Amino Acid Antiporters Have Asymmetric Substrate Specificity?. Biomolecules 13(2) PMID: 36830670
- 2. Bin BH et al.. 2018. Function, Structure, and Transport Aspects of ZIP and ZnT Zinc Transporters in Immune Cells.. J Immunol Res 2018:9365747 PMID: 30370308
- 3. Bai J et al.. 2021. Rice aquaporin OsPIP2;2 is a water-transporting facilitator in relevance to drought-tolerant responses.. Plant Direct 5(8):e338 PMID: 34430793
- 4. Tao S et al.. 2021. N-Acyl-Homoserine Lactones May Affect the Gut Health of Low-Birth-Weight Piglets by Altering Intestinal Epithelial Cell Barrier Function and Amino Acid Metabolism.. J Nutr 151(7):1736-1746 PMID: 33982101
- 5. Schwacke R et al.. 1999. LeProT1, a transporter for proline, glycine betaine, and gamma-amino butyric acid in tomato pollen.. Plant Cell 11(3):377-92 PMID: 10072398
- 6. Peleh V et al.. 2016. Mia40 is a trans-site receptor that drives protein import into the mitochondrial intermembrane space by hydrophobic substrate binding.. Elife 5 PMID: 27343349
- 7. Allison DS et al.. 1988. Single-amino-acid substitutions within the signal sequence of yeast prepro-alpha-factor affect membrane translocation.. Mol Cell Biol 8(5):1915-22 PMID: 3290645
