GO:0016323 basolateral plasma membrane: Components, Assembly and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0016323 basolateral plasma membrane describes the basal and lateral regions of the plasma membrane in polarized cells, including the basal domain attached to the extracellular matrix and the lateral domain facing neighboring cells.
• The basolateral membrane is biochemically and biophysically distinct from the apical membrane, with different lipid compositions and protein residents that maintain epithelial polarity.
• Formation of the basolateral domain depends on phosphatidylinositol-3,4,5-trisphosphate (PIP3) signaling, which is required for the assembly of this membrane territory in epithelial cells.
• Key basolateral proteins include ABCC6, aquaporin-2, the sodium/iodide symporter (NIS), and the PDZ protein SCRIB, which regulate transport, detoxification, and cell polarity.
• Disruption of basolateral membrane composition or trafficking is linked to diseases such as pseudoxanthoma elasticum, cholestatic liver disease, and thyroid dysfunction.
• Research on this compartment uses domain-specific isolation, lipidomics, and imaging to resolve its unique properties and roles in health and disease.
Description
The basolateral plasma membrane (GO:0016323) is a specialized region of the cell surface that includes the basal end and the lateral sides of polarized cells. In animal epithelial cells, the basal membrane contacts the extracellular matrix, while the lateral membrane mediates cell-cell adhesion and communication; in plant cells, the basal membrane is defined relative to the zygotic axis. This domain is essential for vectorial transport, signal transduction, and tissue architecture, and its identity is maintained by distinct lipid and protein compositions. Researchers study the basolateral membrane to understand epithelial polarity, organ physiology, and diseases caused by mistargeting of membrane proteins. The basolateral domain is not merely a passive barrier; it actively sorts and retains specific transporters, channels, and receptors that are critical for ion homeostasis, nutrient uptake, and detoxification. For example, aquaporin-2 must be correctly targeted to the apical membrane after basolateral cholesterol depletion, highlighting the interdependence of membrane domains. Similarly, the sodium/iodide symporter (NIS) is expressed at the basolateral membrane of thyroid cells, and its regulation by SCRIB is necessary for iodide uptake. These examples illustrate why the basolateral plasma membrane is a central topic in cell biology and medicine.
basolateral plasma membrane At A Glance
| GO ID | GO:0016323 |
|---|---|
| GO term | basolateral plasma membrane |
| Ontology | cellular_component |
| Synonym | None |
| Major function | Provides a specialized membrane domain for vectorial transport, cell-cell adhesion, and signal transduction in polarized cells |
| Definition source | QuickGO definition: The region of the plasma membrane that includes the basal end and sides of the cell. |
| Related cellular component | Apical plasma membrane (GO:0016324) |
| Example resident proteins | ABCC6, aquaporin-2, NIS, SCRIB |
| Key lipid property | Distinct lipidome and biophysical properties compared to apical membrane |
What Is GO:0016323?
According to the Gene Ontology, GO:0016323 basolateral plasma membrane is defined as the region of the plasma membrane that includes the basal end and sides of the cell. This term is often used in reference to animal polarized epithelial membranes, where the basal membrane is the part attached to the extracellular matrix, or in plant cells, where the basal membrane is defined with respect to the zygotic axis. In practice, it refers to the portion of the cell surface that faces the basement membrane and adjacent cells, as opposed to the apical membrane that faces the lumen or external environment.
Why Is basolateral plasma membrane Important in Cell Biology?
The basolateral plasma membrane is fundamental to the function of polarized cells, which line organs such as the kidney, liver, thyroid, and intestine. It ensures that transporters and channels are correctly positioned to drive directional transport of ions, water, and solutes, and it participates in cell-cell adhesion and signaling. Defects in basolateral membrane composition or trafficking underlie a range of human diseases, including cholestatic liver disease, pseudoxanthoma elasticum, and thyroid dyshormonogenesis. Understanding this domain is therefore critical for physiology, drug development, and disease modeling.
• Maintains epithelial polarity by segregating apical and basolateral proteins and lipids.
• Enables vectorial transport of ions, water, and nutrients across epithelia.
• Serves as the site for hormone and growth factor receptors that signal from the basolateral side.
• Regulates detoxification and drug efflux through transporters such as ABCC6.
• Is essential for thyroid hormone synthesis via basolateral NIS-mediated iodide uptake.
• Its disruption is linked to cholestatic liver diseases and other transport disorders.
• Provides a platform for cell-cell adhesion and communication with neighboring cells.
• Is a target for pathogens and toxins that exploit basolateral receptors.
• Its lipid composition influences membrane protein function and trafficking.
• Offers opportunities for targeted drug delivery and gene therapy in polarized tissues.
What Happens During basolateral plasma membrane?
Formation and maintenance of the basolateral domain
In simple terms: The cell builds and keeps a distinct basolateral side by using specific lipid signals and protein sorting.
The formation of the basolateral plasma membrane in epithelial cells requires phosphatidylinositol-3,4,5-trisphosphate (PIP3), which regulates the assembly of this membrane territory. This process involves the targeted delivery of proteins and lipids to the basolateral surface, and the exclusion of apical components. The PDZ protein SCRIB plays a key role in maintaining basolateral identity by regulating the expression of resident proteins such as the sodium/iodide symporter (NIS). Disruption of PIP3 signaling impairs basolateral membrane formation, leading to loss of polarity.
Protein sorting and trafficking to the basolateral membrane
In simple terms: Proteins destined for the basolateral side are packaged and shipped to the correct location.
Apical and basolateral protein transport is mediated by distinct sorting signals and vesicular carriers. Basolateral targeting often relies on cytoplasmic motifs that interact with adaptor complexes, ensuring that proteins like aquaporin-2 and ABCC6 reach the basolateral domain. Cholesterol depletion at the basolateral membrane alters post-translational modifications of aquaporin-2 and disrupts its apical targeting, indicating cross-talk between membrane domains. Thus, correct sorting is essential for epithelial function.
Lipid composition and biophysical properties
In simple terms: The basolateral membrane has a unique mix of fats that give it special physical properties.
The apical and basolateral plasma membranes of epithelial cells have distinct lipidomes and biophysical properties. This asymmetry is crucial for membrane protein function, signaling, and barrier properties. For example, specific lipids in the basolateral membrane may influence the activity of transporters and receptors. Techniques such as lipidomics and biophysical measurements have revealed that these differences are maintained despite continuous membrane trafficking.
Isolation and characterization of basolateral membrane domains
In simple terms: Scientists can separate the basolateral part of the membrane from the rest to study it.
Methods have been developed to isolate apical and basolateral plasma membrane domains from cultured cells, such as rat cholangiocytes, using density gradient centrifugation and domain-specific markers. These preparations allow biochemical and functional analyses of resident proteins and lipids. Such studies have been instrumental in defining the composition and roles of the basolateral membrane in transport and signaling.
Key Genes Involved in GO:0016323 basolateral plasma membrane
The following genes encode proteins that localize to or regulate the basolateral plasma membrane, serving as key markers and functional players in epithelial polarity and transport.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ABCC6 | ATP-binding cassette transporter localized to the basolateral membrane of hepatocytes and other cells | Mutations cause pseudoxanthoma elasticum; model for basolateral transport studies |
| AQP2 | Aquaporin-2 water channel; basolateral cholesterol depletion affects its post-translational modifications and apical targeting | Studied in kidney collecting duct; link between basolateral membrane and water homeostasis |
| SLC5A5 (NIS) | Sodium/iodide symporter; mediates iodide uptake at the basolateral membrane of thyroid cells | Regulated by SCRIB; target for thyroid cancer imaging and therapy |
| SCRIB | PDZ scaffold protein; regulates NIS expression at the basolateral membrane | Key polarity regulator; knockout models show loss of basolateral identity |
| PIP3 (phosphatidylinositol-3,4,5-trisphosphate) | Lipid signal required for basolateral membrane formation | Studied via PIP3 manipulation; essential for epithelial polarity |
| CDH1 (E-cadherin) | Cell-cell adhesion protein at the lateral membrane | Marker of basolateral domain; used in polarity studies |
| EPCAM | Epithelial cell adhesion molecule; often apical, but its sorting is compared to basolateral proteins | Model for apical vs. basolateral sorting |
| LDLR | Low-density lipoprotein receptor; basolateral in some epithelia | Studied in polarized transport |
| ATP1A1 (Na+/K+-ATPase) | Ion pump localized to the basolateral membrane | Classic basolateral marker; essential for ion gradients |
| SLC4A2 (AE2) | Anion exchanger at the basolateral membrane of cholangiocytes | Studied in bile formation; isolated from basolateral vesicles |
| CFTR | Chloride channel; apical in most epithelia, but sorting compared to basolateral proteins | Model for domain-specific trafficking |
| TFRC (transferrin receptor) | Basolateral recycling receptor | Used as a basolateral marker in transport assays |
| ITGB1 (integrin beta 1) | Basal adhesion receptor | Marker of basal membrane; studied in cell-matrix adhesion |
| COL4A1 | Basement membrane collagen; interacts with basal membrane | Extracellular matrix component influencing basolateral domain |
| RAB11A | Small GTPase involved in basolateral recycling | Regulates basolateral trafficking |
| RAB8A | GTPase implicated in basolateral transport | Studied in polarized sorting |
| LLGL1 (Lgl) | Polarity protein at the basolateral membrane | Conserved regulator of basolateral identity |
| DLG1 (SAP97) | Scaffold protein at the basolateral membrane | Involved in basolateral protein clustering |
How Is basolateral plasma membrane Regulated?
The basolateral plasma membrane is dynamically regulated by lipid signaling, protein sorting machinery, and post-translational modifications. Phosphatidylinositol-3,4,5-trisphosphate (PIP3) is required for the formation of the basolateral domain, and its local production directs membrane identity. Cholesterol levels in the basolateral membrane influence the post-translational modifications and targeting of aquaporin-2, showing that lipid environment can regulate protein fate. The PDZ protein SCRIB regulates the expression of NIS at the basolateral membrane, linking polarity complexes to transporter abundance. Additionally, Rab GTPases and adaptor proteins control the vesicular trafficking that maintains the distinct composition of this domain. These regulatory layers ensure that the basolateral membrane adapts to physiological demands and maintains epithelial function.
basolateral plasma membrane and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ABCC6 | Pseudoxanthoma elasticum; ectopic mineralization | Knockout or point-mutation knock-in in hepatocyte cell lines; basolateral localization assays |
| SLC5A5 (NIS) | Thyroid dyshormonogenesis; thyroid cancer | SCRIB knockout or overexpression in thyroid cells; iodide uptake assays |
| AQP2 | Nephrogenic diabetes insipidus; water balance | Cholesterol manipulation in kidney cells; AQP2 trafficking assays |
| SLC4A2 (AE2) | Cholestatic liver disease; bile formation | Isolation of basolateral vesicles from cholangiocytes; transport assays |
| SCRIB | Epithelial polarity disorders; cancer | Knockout in polarized epithelial cells; NIS expression analysis |
Basolateral membrane defects in cholestatic liver disease
The basolateral membrane of cholangiocytes and hepatocytes contains transporters essential for bile formation, such as the anion exchanger AE2 (SLC4A2). Isolation and characterization of basolateral vesicles from rat cholangiocytes have provided insights into bile secretory mechanisms. Disruption of basolateral transport can lead to cholestasis, a condition characterized by impaired bile flow. Studying these domains helps identify targets for therapeutic intervention in liver diseases.
ABCC6 and pseudoxanthoma elasticum
ABCC6 is a basolateral plasma membrane protein in hepatocytes, and mutations in ABCC6 cause pseudoxanthoma elasticum, a disorder affecting connective tissue. The basolateral localization of ABCC6 is critical for its function in exporting ATP or other substrates that influence mineralization. Research on ABCC6 trafficking and function at the basolateral membrane provides a model for understanding how membrane protein mislocalization contributes to disease.
SCRIB, NIS, and thyroid dysfunction
The sodium/iodide symporter (NIS) is expressed at the basolateral membrane of thyroid follicular cells, where it mediates iodide uptake for thyroid hormone synthesis. The PDZ protein SCRIB regulates NIS expression at this domain, and loss of SCRIB leads to reduced NIS levels and impaired iodide uptake. This pathway is relevant to thyroid dyshormonogenesis and thyroid cancer, where NIS expression is often altered. Understanding basolateral regulation of NIS can inform diagnostic and therapeutic strategies.
Aquaporin-2 and water balance disorders
Aquaporin-2 (AQP2) is a water channel that must be correctly targeted to the apical membrane of kidney collecting duct cells to regulate water reabsorption. Basolateral cholesterol depletion alters AQP2 post-translational modifications and disrupts its apical targeting, indicating that basolateral membrane integrity influences apical protein delivery. This interplay is relevant to nephrogenic diabetes insipidus and other water balance disorders. Studying basolateral membrane composition may reveal new therapeutic approaches.
From basolateral plasma membrane-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of SCRIB affect NIS localization at the basolateral membrane? | SCRIB knockout in thyroid epithelial cells followed by immunofluorescence and iodide uptake |
| How does basolateral cholesterol depletion impact AQP2 targeting? | Cholesterol depletion in kidney cells; AQP2 post-translational modification and apical targeting assays |
| Is PIP3 required for basolateral membrane formation? | PIP3 manipulation in epithelial cells; domain-specific marker staining |
| What is the lipid composition of the basolateral membrane? | Lipidomics of isolated apical and basolateral membranes from epithelial cells |
| Can ABCC6 basolateral localization be restored by point mutation? | Knock-in of disease-associated ABCC6 mutations in hepatocyte lines; basolateral trafficking assays |
| How are basolateral proteins sorted in polarized cells? | Overexpression of tagged basolateral proteins in epithelial cells; live imaging |
How to Study the basolateral plasma membrane Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Density gradient centrifugation | Separation of apical and basolateral membrane vesicles | Isolation of domain-specific membranes from cultured cells |
| Lipidomics (mass spectrometry) | Lipid composition of membrane domains | Comparing apical vs. basolateral lipidomes |
| Fluorescence microscopy | Localization of tagged proteins | Assessing basolateral targeting of NIS, AQP2, ABCC6 |
| Iodide uptake assay | Functional activity of NIS | Measuring basolateral iodide transport in thyroid cells |
| Anion exchange assay | Activity of AE2 (SLC4A2) | Studying bile formation in cholangiocytes |
| Immunoblotting | Protein expression and post-translational modifications | Analyzing AQP2 modifications after cholesterol depletion |
| Live-cell imaging | Dynamic trafficking of basolateral proteins | Tracking vesicular transport in polarized cells |
| Biophysical spectroscopy | Membrane order and fluidity | Characterizing basolateral membrane properties |
Isolation of basolateral membrane domains
Biochemical isolation of apical and basolateral plasma membrane domains from cultured epithelial cells, such as rat cholangiocytes, allows direct analysis of their composition and function. These methods typically use density gradient centrifugation and domain-specific markers to separate the two membrane populations. Isolated basolateral vesicles can be used for transport assays, proteomics, and lipidomics.
Lipidomics and biophysical characterization
Lipidomic profiling and biophysical measurements reveal that apical and basolateral membranes have distinct lipid compositions and properties. Techniques such as mass spectrometry and fluorescence spectroscopy can quantify lipid species and membrane order. These approaches help link membrane composition to protein function and cellular polarity.
Imaging and protein trafficking assays
Fluorescence microscopy and live-cell imaging are used to track the localization and trafficking of basolateral proteins such as NIS, AQP2, and ABCC6. Tagged proteins and domain-specific antibodies allow researchers to monitor sorting and membrane delivery. These methods are essential for understanding how mutations or treatments affect basolateral targeting.
Functional transport assays
Transport assays measure the activity of basolateral transporters and channels, such as iodide uptake by NIS or anion exchange by AE2. These assays can be performed on polarized cell monolayers or isolated membrane vesicles. They provide functional readouts to complement localization studies.
How CRISPR Can Be Used to Study GO:0016323 basolateral plasma membrane
Knockout
CRISPR knockout of genes encoding basolateral membrane proteins or regulators, such as SCRIB or ABCC6, can reveal their roles in epithelial polarity and transport. For example, SCRIB knockout reduces NIS expression at the basolateral membrane, demonstrating its regulatory function. Knockout models are valuable for studying loss-of-function phenotypes and disease mechanisms.
Point Mutation
Introducing disease-associated point mutations into genes like ABCC6 or AQP2 allows researchers to study how specific amino acid changes affect basolateral localization and function. Point-mutation knock-in models can mimic human mutations and provide insights into trafficking defects. These models are particularly useful when the mutation is known to cause misfolding or mislocalization.
Knock-in
Knock-in of tagged versions of basolateral proteins, such as GFP-tagged NIS or AQP2, enables real-time imaging and biochemical analysis of their trafficking. Tagged knock-in cell lines preserve endogenous regulation and are ideal for studying dynamic processes. This approach can also be used to introduce reporter genes for high-throughput screening.
Overexpression
Overexpression of basolateral proteins or their regulators can help identify dominant effects on membrane domain formation and function. For instance, overexpression of PIP3-modifying enzymes can alter basolateral membrane assembly. Overexpression models are useful for gain-of-function studies and for producing sufficient material for biochemical assays.
How EDITGENE Supports basolateral plasma membrane Research
Researchers studying basolateral plasma membrane-related genes often need to determine whether a candidate gene is causally involved in membrane domain formation, protein trafficking, or disease. EDITGENE provides a comprehensive suite of CRISPR-based services to create precise cell models that answer these questions.
Contact EDITGENE today to design your custom CRISPR model for basolateral plasma membrane research.
Frequently Asked Questions About basolateral plasma membrane
What is the basolateral plasma membrane?
The basolateral plasma membrane (GO:0016323) is the region of the plasma membrane that includes the basal end and sides of the cell, often studied in polarized epithelial cells where it faces the extracellular matrix and neighboring cells.
What genes are involved in the basolateral plasma membrane?
Key genes include ABCC6, AQP2, SLC5A5 (NIS), SCRIB, ATP1A1, and SLC4A2, which encode proteins that localize to or regulate this domain.
How is the basolateral membrane different from the apical membrane?
The basolateral and apical membranes have distinct lipid compositions and protein residents, which are maintained by sorting and trafficking mechanisms.
What is the role of PIP3 in basolateral membrane formation?
Phosphatidylinositol-3,4,5-trisphosphate (PIP3) is required for the formation of the basolateral plasma membrane in epithelial cells.
Which diseases are linked to basolateral membrane proteins?
Mutations in ABCC6 cause pseudoxanthoma elasticum, and defects in NIS regulation are linked to thyroid dysfunction; basolateral transport defects also contribute to cholestasis.
How can I study basolateral membrane proteins?
Researchers use isolation of membrane domains, lipidomics, imaging, and functional transport assays to study basolateral proteins.
What is the function of SCRIB at the basolateral membrane?
SCRIB is a PDZ protein that regulates the expression of NIS at the basolateral membrane, influencing iodide uptake in thyroid cells.
How does cholesterol affect aquaporin-2 targeting?
Basolateral cholesterol depletion alters aquaporin-2 post-translational modifications and disrupts its apical targeting, showing cross-talk between membrane domains.
What methods are used to isolate basolateral membranes?
Density gradient centrifugation and domain-specific markers are used to isolate basolateral membrane vesicles from cultured cells.
Can CRISPR be used to study basolateral membrane genes?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools to study the function of basolateral membrane genes.
Conclusion
The basolateral plasma membrane (GO:0016323) is a specialized membrane domain essential for epithelial polarity, vectorial transport, and cell-cell communication. Its unique lipid and protein composition is maintained by signaling pathways such as PIP3 and by sorting machinery that includes SCRIB and Rab GTPases. Dysregulation of basolateral proteins like ABCC6, NIS, and AQP2 leads to human diseases, making this domain a critical area of research. Advances in CRISPR-based cell modeling and omics technologies continue to illuminate the mechanisms governing basolateral membrane biology, offering new opportunities for therapeutic intervention.
References
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- 2. Delacour D et al.. 2006. Apical protein transport.. Cell Mol Life Sci 63(21):2491-505 PMID: 16927027
- 3. Tietz P et al.. 1997. Characterization of apical and basolateral plasma membrane domains derived from cultured rat cholangiocytes.. Anal Biochem 254(2):192-9 PMID: 9417776
- 4. Martín M et al.. 2021. The PDZ protein SCRIB regulates sodium/iodide symporter (NIS) expression at the basolateral plasma membrane.. FASEB J 35(8):e21681 PMID: 34196428
- 5. Gassama-Diagne A et al.. 2006. Phosphatidylinositol-3,4,5-trisphosphate regulates the formation of the basolateral plasma membrane in epithelial cells.. Nat Cell Biol 8(9):963-70 PMID: 16921364
- 6. Pomozi V et al.. 2013. ABCC6 is a basolateral plasma membrane protein.. Circ Res 112(11):e148-51 PMID: 23625951
- 7. Tietz PS et al.. 1995. Isolation and characterization of rat cholangiocyte vesicles enriched in apical or basolateral plasma membrane domains.. Biochemistry 34(47):15436-43 PMID: 7492544
- 8. Shurer CR et al.. 2026. Apical and basolateral plasma membranes in epithelial cells have distinct lipidomes and biophysical properties.. Proc Natl Acad Sci U S A 123(6):e2521220123 PMID: 41637448
