GO:1903361 protein localization to basolateral plasma membrane: Components, Assembly and Research Methods, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1903361 describes the biological process by which proteins are transported to or maintained at the basolateral region of the plasma membrane, a key feature of polarized epithelial and endothelial cells [2,4].
• Basolateral localization is essential for vectorial transport, cell-cell adhesion, and signaling, and its disruption is linked to diseases such as cancer and cholestasis [2,7,8].
• The process relies on sorting signals, adaptor proteins, and cytoskeletal elements, and is regulated by phosphorylation and lipid interactions [4,7].
• Key proteins include ABCC6, AQP2, MRP2, and Na+-taurocholate co-transporting polypeptide (NTCP), which are targeted to the basolateral membrane in specific tissues [2,3,5,8].
• Experimental approaches such as knockout, knock-in, and tagged knock-in models in polarized cell lines enable precise dissection of basolateral targeting mechanisms [2,4].
• EDITGENE provides CRISPR-based services to generate such models, accelerating research on basolateral protein localization and related diseases.
Description
The plasma membrane of polarized cells is divided into apical and basolateral domains, each with distinct protein and lipid compositions. The process of protein localization to basolateral plasma membrane (GO:1903361) ensures that specific proteins are delivered to and retained at the basolateral surface, which is essential for vectorial transport, cell adhesion, and signal transduction [2,4]. This process is fundamental for epithelial and endothelial function, and its dysregulation contributes to various pathologies, including cancer and metabolic disorders [7,8]. Understanding the molecular mechanisms of basolateral targeting is therefore of broad biomedical importance. This article integrates authoritative QuickGO data with published literature to provide a comprehensive overview of GO:1903361, covering its definition, mechanisms, key genes, disease associations, and research methodologies.
protein localization to basolateral plasma membrane At A Glance
| GO ID | GO:1903361 |
|---|---|
| GO term | protein localization to basolateral plasma membrane |
| Ontology | biological_process |
| Synonym | basolateral protein localization; protein localisation in basolateral plasma membrane; protein localisation to basolateral plasma membrane; protein localization in basolateral plasma membrane |
| Major function | Transport and maintenance of proteins at the basolateral plasma membrane domain of polarized cells |
| Related cellular component | basolateral plasma membrane |
| Related biological processes | protein targeting, vesicle-mediated transport, cell polarity establishment |
| Key regulators | Sorting signals, adaptor proteins (e.g., retromer), cytoskeleton, phosphorylation |
What Is GO:1903361?
GO:1903361, protein localization to basolateral plasma membrane, is defined as any process in which a protein is transported to, or maintained in, basolateral regions of the plasma membrane. This encompasses the sorting, trafficking, and retention of proteins at the basolateral domain, distinguishing it from apical localization. The term is a biological process and includes synonyms such as basolateral protein localization and protein localisation to basolateral plasma membrane.
Why Is protein localization to basolateral plasma membrane Important in Cell Biology?
Protein localization to the basolateral plasma membrane is critical for the proper functioning of polarized cells, which line organs such as the kidney, liver, and intestine. It ensures the asymmetric distribution of transporters, receptors, and adhesion molecules, enabling directional transport of ions, nutrients, and waste products [2,3,8]. Defects in basolateral targeting can lead to mislocalization of proteins, resulting in diseases like progressive familial intrahepatic cholestasis, cystic fibrosis, and cancer [2,7,8]. Moreover, basolateral localization is exploited by pathogens and is relevant to drug delivery and tissue engineering. Thus, understanding GO:1903361 is essential for both basic cell biology and translational medicine.
• Maintains epithelial polarity and barrier function.
• Enables vectorial transport in kidney and liver [2,3,8].
• Required for cell-cell adhesion and signaling.
• Dysregulation linked to cancer progression and metastasis.
• Mutations in basolateral proteins cause cholestasis and other transport disorders [2,8].
• Target for pharmacological modulation of drug transporters.
• Involved in viral entry and pathogenesis.
• Provides insights into membrane trafficking mechanisms.
• Facilitates development of polarized cell models for drug screening [2,4].
• Offers potential biomarkers for disease diagnosis [2,7].
What Happens During protein localization to basolateral plasma membrane?
Sorting at the Trans-Golgi Network
In simple terms: Proteins destined for the basolateral membrane are first sorted in the Golgi apparatus.
After synthesis in the endoplasmic reticulum, proteins are transported to the trans-Golgi network (TGN), where they are segregated into distinct vesicles based on sorting signals. Basolateral targeting signals, often located in the cytoplasmic tail, interact with adaptor protein complexes such as AP-1B, which mediate incorporation into basolateral transport vesicles. This step is crucial for excluding proteins from apical routes and ensuring correct delivery.
Vesicle Transport and Cytoskeletal Guidance
In simple terms: Vesicles carrying basolateral proteins travel along the cytoskeleton to the correct side of the cell.
Basolateral transport vesicles are transported along microtubules and actin filaments to the basolateral membrane. Motor proteins such as kinesins and myosins facilitate this movement, while the cytoskeleton provides directional cues. The retromer complex also plays a role in recycling basolateral proteins from endosomes back to the plasma membrane, maintaining their steady-state localization.
Tethering and Fusion at the Basolateral Membrane
In simple terms: The vesicle docks and fuses with the basolateral membrane, releasing the protein.
Upon reaching the basolateral membrane, vesicles are tethered by proteins such as exocyst components and then fuse via SNARE-mediated mechanisms. This ensures the delivery of cargo proteins to the correct domain. Specific lipids, such as phosphatidylinositol 4,5-bisphosphate, may also contribute to membrane identity and fusion.
Retention and Maintenance
In simple terms: Once delivered, proteins are kept at the basolateral membrane by anchoring and recycling.
After insertion, proteins may be retained at the basolateral membrane through interactions with the cytoskeleton, such as via PDZ domain-containing scaffolds, or by continuous recycling that prevents their accumulation at the apical surface. For example, ABCC6 is a basolateral plasma membrane protein in hepatocytes, and its localization is maintained by yet-to-be-fully-defined mechanisms. Similarly, aquaporin-2 is targeted to the basolateral membrane in some renal cells, and its trafficking is regulated by phosphorylation.
Key Genes Involved in GO:1903361 protein localization to basolateral plasma membrane
The following genes and proteins are key players in the process of protein localization to the basolateral plasma membrane, as supported by published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ABCC6 | Basolateral plasma membrane protein in hepatocytes | Mutations cause pseudoxanthoma elasticum; model for basolateral targeting |
| AQP2 | Water channel; basolateral localization in renal cells | Regulated trafficking; diabetes insipidus |
| ABCC2 (MRP2) | Multidrug resistance-associated protein; basolateral in brain endothelial cells | Drug transport; blood-brain barrier |
| SLC10A1 (NTCP) | Na+-taurocholate co-transporting polypeptide; basolateral in hepatocytes | Bile acid transport; regulated by bile acids |
| DIO1 | Type I iodothyronine deiodinase; basolateral in renal cells | Thyroid hormone metabolism |
| ATP6V1A | Vacuolar H+-ATPase subunit; basolateral in kidney | Acid-base regulation; renal physiology |
| DLG1 (SAP97) | Scaffold protein; basolateral targeting | Cell polarity and tumorigenesis |
| AP1B1 | Adaptor protein complex 1B; basolateral sorting | Epithelial polarity |
| VPS35 | Retromer component; recycling of basolateral proteins | Polarized transport |
| EXOC7 | Exocyst component; vesicle tethering | Basolateral exocytosis |
| STX4 | SNARE protein; basolateral fusion | Membrane fusion |
| MYO5B | Myosin Vb; vesicle transport | Basolateral trafficking |
| RAB8A | Small GTPase; basolateral transport | Vesicle trafficking |
| RAB11A | Small GTPase; recycling endosomes | Basolateral recycling |
| LLGL1 | Cell polarity regulator | Basolateral domain establishment |
| SCRIB | Scaffold protein; basolateral polarity | Tumor suppression |
| PRKCI | Atypical protein kinase C; polarity | Basolateral targeting |
How Is protein localization to basolateral plasma membrane Regulated?
The process of protein localization to the basolateral plasma membrane is regulated at multiple levels. Phosphorylation of cargo proteins or adaptors can modulate sorting signals; for example, the Na+-taurocholate co-transporting polypeptide (NTCP) is regulated by bile acids via phosphorylation. The retromer complex mediates recycling and is subject to regulation by small GTPases. Additionally, lipid composition and electrostatic interactions contribute to targeting, as shown for Dlg (Discs large) in cell polarity. Hormonal signals, such as vasopressin, regulate aquaporin-2 trafficking to the basolateral membrane in renal cells. These regulatory mechanisms ensure dynamic control of basolateral protein composition in response to physiological demands.
protein localization to basolateral plasma membrane and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ABCC6 | Pseudoxanthoma elasticum | Knockout mouse or human hepatocyte cell line |
| SLC10A1 (NTCP) | Cholestasis, hypercholanemia | Knockout or point-mutation in HepG2 cells |
| AQP2 | Nephrogenic diabetes insipidus | Knock-in of tagged AQP2 in renal epithelial cells |
| DLG1 | Cancer, polarity defects | Knockout or overexpression in MDCK cells |
| ATP6V1A | Distal renal tubular acidosis | Knockout in kidney cell lines |
Cancer and Cell Polarity
Disruption of basolateral protein localization is associated with loss of cell polarity and cancer progression. The scaffold protein Dlg (encoded by DLG1) is targeted to the basolateral membrane via electrostatic interactions, and its mislocalization contributes to tumorigenesis in epithelial tissues. Similarly, mutations in polarity regulators can lead to uncontrolled cell proliferation and metastasis.
Cholestasis and Transport Defects
ABCC6 is a basolateral plasma membrane protein in hepatocytes, and its mutations cause pseudoxanthoma elasticum, a disorder affecting connective tissue. In addition, the bile acid transporter NTCP (SLC10A1) is basolateral in hepatocytes, and its dysfunction is linked to cholestasis and hypercholanemia. Proper basolateral localization of these transporters is essential for bile acid homeostasis.
Renal Disorders
In the kidney, aquaporin-2 (AQP2) is targeted to the basolateral membrane in some cells, and its misregulation leads to nephrogenic diabetes insipidus. Similarly, the vacuolar H+-ATPase is localized to the basolateral membrane of renal intercalated cells, where it regulates acid-base balance; defects contribute to distal renal tubular acidosis.
From protein localization to basolateral plasma membrane-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X regulate basolateral localization of protein Y? | Knockout of gene X in polarized epithelial cells (e.g., MDCK) |
| Does a point mutation in the sorting signal affect basolateral targeting? | Point-mutation knock-in of the cargo protein |
| Where does a protein localize in real time? | Tagged knock-in with fluorescent protein |
| Can overexpression rescue a localization defect? | Overexpression of wild-type or mutant protein |
| What is the role of a specific adaptor in basolateral transport? | Knockout or knockdown of adaptor (e.g., AP-1B) |
| Does a disease-associated mutation alter basolateral localization? | Knock-in of patient mutation in cell line |
How to Study the protein localization to basolateral plasma membrane Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Confocal microscopy | Subcellular localization of fluorescently tagged proteins | Assessing basolateral vs. apical distribution |
| Live-cell imaging | Real-time trafficking of proteins | Vesicle transport dynamics |
| Membrane fractionation | Protein distribution in apical/basolateral fractions | Quantifying basolateral enrichment |
| Western blotting | Protein expression and localization | Validating fractionation results |
| Proteomics | Protein composition of basolateral membranes | Identifying novel basolateral proteins |
| CRISPR knockout screen | Genes required for basolateral localization | Discovery of new regulators |
| RNA-seq | Transcriptional changes upon perturbation | Pathway analysis |
| Proximity ligation assay | Protein-protein interactions in situ | Detecting basolateral protein complexes |
Fluorescence Microscopy and Live Imaging
Confocal and live-cell imaging of fluorescently tagged proteins (e.g., GFP, mCherry) allows visualization of basolateral localization and trafficking dynamics in polarized cells. This method is widely used to assess the effects of mutations or drug treatments on basolateral targeting [2,3].
Biochemical Fractionation and Western Blotting
Domain-specific fractionation (e.g., apical vs. basolateral membrane isolation) followed by immunoblotting can quantify the distribution of proteins. This approach is useful for confirming basolateral localization of endogenous proteins like ABCC6 and NTCP [2,8].
Proteomics and Mass Spectrometry
Mass spectrometry-based proteomics can identify proteins enriched at the basolateral membrane and reveal interaction partners. This is valuable for discovering novel components of the basolateral targeting machinery.
CRISPR Screening and Functional Genomics
Genome-wide CRISPR knockout screens can identify genes required for basolateral localization of a reporter protein. This unbiased approach can uncover new regulators and pathways.
How CRISPR Can Be Used to Study GO:1903361 protein localization to basolateral plasma membrane
Knockout
CRISPR knockout of candidate genes (e.g., AP1B1, VPS35) in polarized cell lines can abolish basolateral localization of cargo proteins, confirming their essential roles. This approach is straightforward and can be scaled for screens.
Point Mutation
Introducing point mutations in sorting signals or phosphorylation sites of cargo proteins (e.g., NTCP) via CRISPR can reveal critical residues for basolateral targeting. This provides mechanistic insights into signal recognition.
Knock-in
Knock-in of fluorescent or epitope tags at endogenous loci allows real-time tracking of basolateral proteins under native regulation. For example, tagging AQP2 enables visualization of its trafficking in renal cells.
Overexpression
Overexpression of wild-type or mutant proteins can test sufficiency for basolateral localization and rescue phenotypes. This is useful for dominant-negative studies and for assessing saturation of targeting machinery.
How EDITGENE Supports protein localization to basolateral plasma membrane Research
Researchers studying protein localization to basolateral plasma membrane-related genes often need to determine whether a candidate gene is causally involved in targeting, retention, or regulation. EDITGENE provides a comprehensive suite of CRISPR-based services to generate precisely engineered cell models, enabling rigorous functional studies.
Contact EDITGENE today to design your custom CRISPR model for protein localization to basolateral plasma membrane research.
Frequently Asked Questions About protein localization to basolateral plasma membrane
What is protein localization to basolateral plasma membrane?
It is the biological process (GO:1903361) by which proteins are transported to or maintained at the basolateral domain of the plasma membrane in polarized cells [2,4].
What genes are involved in protein localization to basolateral plasma membrane?
Key genes include ABCC6, AQP2, ABCC2, SLC10A1, DLG1, AP1B1, VPS35, and others involved in sorting and trafficking [2,3,4,5,7,8].
Why is basolateral localization important?
It ensures proper vectorial transport, cell polarity, and signaling; defects are linked to diseases like cholestasis and cancer [2,7,8].
How is basolateral localization studied?
Common methods include fluorescence microscopy, membrane fractionation, proteomics, and CRISPR screens [2,3,4,8].
What diseases are associated with defects in basolateral localization?
Diseases include pseudoxanthoma elasticum, cholestasis, nephrogenic diabetes insipidus, and cancer [2,3,7,8].
What is the role of ABCC6 in basolateral localization?
ABCC6 is a basolateral plasma membrane protein in hepatocytes; its mutations cause pseudoxanthoma elasticum.
How does NTCP localize to the basolateral membrane?
NTCP (SLC10A1) is targeted to the basolateral membrane of hepatocytes, and its localization is regulated by bile acids.
Can CRISPR be used to study basolateral localization?
Yes, CRISPR knockout, knock-in, and point mutations enable precise dissection of genes involved in basolateral targeting [4,8].
What is the difference between apical and basolateral localization?
Apical and basolateral are distinct plasma membrane domains; proteins are sorted to one or the other to perform specific functions.
What model systems are used to study basolateral localization?
Polarized epithelial cell lines (e.g., MDCK, HepG2) and knockout mice are commonly used [2,4,7].
Conclusion
Protein localization to the basolateral plasma membrane (GO:1903361) is a fundamental process that underpins epithelial and endothelial function. Its dysregulation contributes to a range of human diseases, making it a critical area of research. By leveraging CRISPR-based models and advanced imaging and proteomic techniques, researchers can uncover the molecular mechanisms governing basolateral targeting. EDITGENE stands ready to support these efforts with tailored gene-editing services.
References
- 1. Wagner CA et al.. 2004. Renal vacuolar H+-ATPase.. Physiol Rev 84(4):1263-314 PMID: 15383652
- 2. Pomozi V et al.. 2013. ABCC6 is a basolateral plasma membrane protein.. Circ Res 112(11):e148-51 PMID: 23625951
- 3. Nedvetsky PI et al.. 2009. Regulation of aquaporin-2 trafficking.. Handb Exp Pharmacol PMID: 19096775
- 4. Vergés M. 2016. Retromer in Polarized Protein Transport.. Int Rev Cell Mol Biol 323:129-79 PMID: 26944621
- 5. Zhang Y et al.. 2004. Plasma membrane localization of multidrug resistance-associated protein homologs in brain capillary endothelial cells.. J Pharmacol Exp Ther 311(2):449-55 PMID: 15218051
- 6. Leonard JL et al.. 1991. Localization of type I iodothyronine 5'-deiodinase to the basolateral plasma membrane in renal cortical epithelial cells.. J Biol Chem 266(17):11262-9 PMID: 2040632
- 7. Lu J et al.. 2021. Electrostatic plasma membrane targeting contributes to Dlg function in cell polarity and tumorigenesis.. Development 148(7) PMID: 33688074
- 8. Mayer PGK et al.. 2019. Regulation of Plasma Membrane Localization of the Na⁺-Taurocholate Co-Transporting Polypeptide by Glycochenodeoxycholate and Tauroursodeoxycholate.. Cell Physiol Biochem 52(6):1427-1445 PMID: 31088037
