GO:0090118 receptor-mediated endocytosis involved in cholesterol transport: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0090118 describes a receptor-mediated endocytosis process specifically dedicated to intracellular cholesterol transport, canonically exemplified by LDL uptake through the LDL receptor (LDLR).
• The pathway moves cholesterol from the plasma membrane to endosomes and lysosomes, then to the endoplasmic reticulum and other organelles through vesicular and non-vesicular routes.
• Endothelial transcytosis of LDL is a key step in delivering cholesterol to tissues and is mechanistically linked to atherosclerosis.
• Cholesterol delivered by this route can be stored as cholesteryl esters or sensed by SREBP/SCAP to control sterol homeostasis.
• Pathogens such as Toxoplasma gondii exploit host LDLR-mediated endocytosis to acquire cholesterol.
• Experimental dissection of this pathway relies on CRISPR knockout, knock-in, overexpression, imaging, and lipidomics approaches.
Description
GO:0090118, receptor-mediated endocytosis involved in cholesterol transport, is a biological process that couples the selective uptake of cholesterol-carrying ligands to the intracellular movement of cholesterol. The best-characterized example is the low-density lipoprotein receptor (LDLR) pathway, in which LDL particles bind LDLR at the cell surface and are internalized into coated vesicles, delivering cholesterol to endosomes and lysosomes. This process is not merely a housekeeping route; it is a regulated entry point for sterol supply that influences membrane biogenesis, steroidogenesis, and whole-body lipid distribution. Researchers study GO:0090118 because defects in cholesterol uptake and trafficking underlie major human diseases, including familial hypercholesterolemia and atherosclerosis. Endothelial cells use receptor-mediated transcytosis to move LDL across the vessel wall, a step that contributes to lipid accumulation in the arterial intima. In addition, intracellular cholesterol trafficking after endocytosis is essential for maintaining organelle lipid composition and signaling. The pathway also intersects with host-pathogen interactions. Toxoplasma gondii exploits host LDLR-mediated endocytosis to acquire cholesterol from the host cell, demonstrating that this process can be co-opted by intracellular parasites. Because cholesterol is hydrophobic and cannot freely diffuse through aqueous compartments, its transport depends on vesicular carriers and sterol-binding proteins, making GO:0090118 a central node in lipid cell biology.
receptor-mediated endocytosis involved in cholesterol transport At A Glance
| GO ID | GO:0090118 |
|---|---|
| GO term | receptor-mediated endocytosis involved in cholesterol transport |
| Ontology | biological_process |
| Synonym | receptor-mediated endocytosis involved in intracellular cholesterol transport; receptor-mediated endocytosis of LDL; receptor-mediated endocytosis of low-density lipoprotein involved in cholesterol transport; receptor-mediated endocytosis of low-density lipoprotein particle involved in cholesterol transport |
| Major function | Selective uptake and intracellular delivery of cholesterol via receptor-ligand internalization |
| Canonical receptor | LDLR, which binds LDL and mediates endocytic uptake |
| Cargo | Low-density lipoprotein particles and associated cholesteryl esters |
| Downstream route | Endosomal/lysosomal processing followed by cholesterol egress to the ER and other organelles |
| Physiological context | Whole-body cholesterol homeostasis, endothelial transcytosis, and tissue lipid supply |
What Is GO:0090118?
GO:0090118 is defined as a receptor-mediated endocytosis process involved in intracellular cholesterol transport. In practical terms, it covers the events in which a cell-surface receptor binds a cholesterol-carrying ligand, invaginates, and delivers that cholesterol to intracellular compartments as part of cholesterol transport. The term includes the canonical LDLR-mediated uptake of low-density lipoprotein and related receptor pathways that move cholesterol into the cell interior.
Why Is receptor-mediated endocytosis involved in cholesterol transport Important in Cell Biology?
GO:0090118 is important because it is the principal regulated route by which cells acquire exogenous cholesterol, and its dysfunction or dysregulation contributes to cardiovascular disease, altered lipid homeostasis, and host-pathogen interactions. Understanding this process at molecular resolution informs therapeutic strategies targeting LDL uptake, endothelial transcytosis, and intracellular cholesterol trafficking.
• Provides cells with cholesterol for membrane synthesis and steroid hormone production.
• Canonical LDLR-mediated endocytosis is a central determinant of plasma cholesterol clearance.
• Endothelial transcytosis of LDL contributes to arterial lipid accumulation and atherosclerosis.
• Intracellular cholesterol trafficking after endocytosis controls organelle lipid composition and signaling.
• Pathogens such as Toxoplasma gondii exploit this pathway for cholesterol acquisition.
• Sphingomyelin-rich membrane domains influence cholesterol organization and endocytic sorting.
• Hepatocellular vesicle-mediated transport pathways intersect with cholesterol transport and bile secretion.
• The pathway is a target for research on familial hypercholesterolemia and lipid-lowering therapeutics.
• CRISPR-based models enable causal testing of candidate genes in this process.
• Imaging and lipidomics can resolve cholesterol distribution after receptor-mediated uptake.
What Happens During receptor-mediated endocytosis involved in cholesterol transport?
Ligand recognition and receptor binding at the plasma membrane
In simple terms: The cell uses a receptor to grab cholesterol-carrying particles at its surface.
The process begins when a cholesterol-carrying ligand, most commonly LDL, binds to its receptor such as LDLR on the plasma membrane. This binding is selective and concentrates cargo at defined membrane sites, setting the stage for internalization. Endothelial cells can also engage transcytosis machinery to move LDL across the cell.
Coated-pit internalization and vesicle formation
In simple terms: The membrane dimples inward and pinches off, trapping the particle inside a small bubble.
After binding, the receptor-ligand complex is internalized through coated pits and vesicles. During receptor-mediated endocytosis of LDL, filipin-cholesterol complexes form in uncoated vesicle membranes derived from coated vesicles, indicating that cholesterol is reorganized as the cargo moves inward. This step requires membrane remodeling and is sensitive to the sterol and sphingomyelin composition of the bilayer.
Endosomal sorting and lysosomal processing
In simple terms: Inside the cell, the bubble matures and delivers its cargo to recycling and degradation stations.
Internalized vesicles mature into endosomes, where receptors can be recycled and cargo is sorted. LDL-derived cholesterol is processed through the endolysosomal system before being released for intracellular transport. This compartmentalization ensures that cholesterol is delivered in a controlled manner rather than randomly mixing with other membranes.
Post-endosomal cholesterol trafficking to the ER and other organelles
In simple terms: After leaving the endosome, cholesterol is carried to the endoplasmic reticulum and other parts of the cell.
Cholesterol exits endosomes and lysosomes via vesicular and non-vesicular routes to reach the endoplasmic reticulum, mitochondria, and plasma membrane. This post-endosomal trafficking is essential for sterol sensing and for maintaining organelle lipid homeostasis. Defects in these steps can cause cholesterol to accumulate in the wrong compartments.
Integration with cellular cholesterol homeostasis
In simple terms: The cell uses the delivered cholesterol to adjust its own production and storage.
Once cholesterol arrives in the endoplasmic reticulum, it participates in regulatory circuits that control sterol synthesis, esterification, and efflux. In hepatocytes, vesicle-mediated transport pathways contribute to bile secretion and whole-body cholesterol handling. Thus GO:0090118 is not an isolated uptake event but part of a broader homeostatic network.
Key Genes Involved in GO:0090118 receptor-mediated endocytosis involved in cholesterol transport
The following genes and proteins are experimentally implicated in receptor-mediated endocytosis involved in cholesterol transport and its downstream cholesterol trafficking.
| Gene | Major Role | Research Relevance |
|---|---|---|
| LDLR | Binds LDL and initiates receptor-mediated endocytosis | Central receptor for cholesterol uptake; knockout and knock-in models test uptake defects |
| APOB | Major apolipoprotein of LDL particles that binds LDLR | Defines the ligand side of the pathway; useful for ligand-receptor interaction studies |
| PCSK9 | Regulates LDLR availability and degradation | Therapeutic target; point mutations alter LDLR recycling |
| ARH | Adaptor protein required for LDLR clustering in coated pits | Loss-of-function causes familial hypercholesterolemia; knockout models probe internalization |
| CLTC | Clathrin heavy chain component of coated pits | Required for vesicle formation during LDL uptake |
| NPC1 | Mediates cholesterol egress from lysosomes | Mutations cause cholesterol trafficking defects; knockout models study post-endosomal transport |
| NPC2 | Soluble lysosomal cholesterol transfer protein | Works with NPC1 in cholesterol export; relevant to trafficking assays |
| SCAP | Sterol-sensing escort for SREBP | Links delivered cholesterol to transcriptional regulation |
| SREBF2 | Transcription factor controlling cholesterol synthesis and uptake | Readout of cholesterol status after endocytosis |
| ABCA1 | Mediates cholesterol efflux to apolipoproteins | Counterbalances uptake; relevant to cellular cholesterol balance |
| SOAT1 | Esterifies cholesterol for storage | Marks cholesterol esterification after delivery |
| SMPD1 | Generates ceramide from sphingomyelin, affecting membrane order | Sphingomyelin metabolism influences endocytic sorting |
| SPTLC1 | Serine palmitoyltransferase subunit for sphingolipid synthesis | Alters sphingomyelin/sterol balance and membrane domains |
| RAB7A | Late endosomal trafficking regulator | Controls endosome maturation and cholesterol egress |
| VPS35 | Retromer component for receptor recycling | Affects receptor availability and endosomal sorting |
| TFRC | Transferrin receptor, a model receptor for endocytosis | Comparative control for receptor-mediated internalization |
| HMGCR | Rate-limiting enzyme of cholesterol synthesis | Feedback-regulated by cholesterol delivered via endocytosis |
How Is receptor-mediated endocytosis involved in cholesterol transport Regulated?
GO:0090118 is regulated at multiple levels. Receptor availability is controlled by transcriptional sterol-sensing pathways, and PCSK9 can promote LDLR degradation, thereby reducing uptake capacity. Membrane lipid composition, including sphingomyelin content, influences the formation and stability of endocytic carriers and cholesterol organization within them. After internalization, endosomal maturation and post-endosomal cholesterol trafficking are regulated by Rab GTPases and lysosomal export proteins such as NPC1 and NPC2. In hepatocytes, vesicle-mediated transport pathways integrate cholesterol handling with bile secretion. Together, these layers tune how much cholesterol enters the cell and where it goes.
receptor-mediated endocytosis involved in cholesterol transport and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| LDLR | Familial hypercholesterolemia; reduced LDL uptake | LDLR knockout and point-mutation knock-in cell lines |
| PCSK9 | Hypercholesterolemia via LDLR degradation | PCSK9 overexpression and gain-of-function knock-in |
| ARH | Autosomal recessive hypercholesterolemia | ARH knockout to test internalization defects |
| NPC1 | Lysosomal cholesterol accumulation | NPC1 knockout with cholesterol trafficking assays |
| NPC2 | Lysosomal cholesterol export defect | NPC2 knockout and rescue with tagged knock-in |
Atherosclerosis and endothelial LDL transcytosis
Receptor-mediated endocytosis and transcytosis of LDL across arterial endothelium contribute to the accumulation of cholesterol in the vessel wall, a hallmark of atherosclerosis. Endothelial cells express receptors that participate in tissue lipid uptake and can move LDL from the lumen into the subendothelial space. This process links GO:0090118 directly to cardiovascular disease risk and to therapeutic strategies aimed at limiting LDL entry into the artery wall.
Familial hypercholesterolemia and defective LDLR uptake
Loss-of-function defects in LDLR or its adaptor ARH impair receptor-mediated endocytosis of LDL, reducing cholesterol clearance and elevating plasma cholesterol. PCSK9 gain-of-function variants similarly reduce LDLR availability and increase cardiovascular risk. These genetic paradigms make GO:0090118 a clinically actionable pathway for diagnosis and drug development.
Lysosomal cholesterol trafficking disorders
After endocytosis, cholesterol must exit the endolysosomal system. Mutations in NPC1 or NPC2 cause cholesterol to accumulate in lysosomes, illustrating how post-endosomal steps of GO:0090118 are essential for cellular health. Research on these trafficking routes continues to reveal new mechanisms of cholesterol egress and organelle homeostasis.
Host-pathogen exploitation of cholesterol uptake
Toxoplasma gondii exploits host LDLR-mediated endocytosis to acquire cholesterol, showing that pathogens can hijack GO:0090118 for their own benefit. This highlights the pathway as a potential host-directed target in infection biology.
From receptor-mediated endocytosis involved in cholesterol transport-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is a candidate gene required for LDL uptake? | CRISPR knockout in hepatocyte or endothelial cell lines |
| Does a patient variant alter receptor function? | Point-mutation knock-in of the variant |
| Where does the receptor localize during uptake? | Tagged knock-in with fluorescent protein |
| Does overexpression change cholesterol delivery? | Doxycycline-inducible overexpression |
| Which genes modify post-endosomal cholesterol trafficking? | CRISPR library screening with lipid readouts |
| Can endothelial transcytosis be blocked? | Endothelial knockout or knock-in models |
How to Study the receptor-mediated endocytosis involved in cholesterol transport Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Filipin staining | Free cholesterol distribution and membrane domains | Visualizing cholesterol in endocytic vesicles |
| Fluorescent LDL uptake | Receptor-mediated internalization rate | Comparing wild-type and mutant cells |
| Lipidomics (LC-MS) | Cholesterol and sphingomyelin species | Quantifying cargo delivery and storage |
| RNA-seq | Transcriptional response to sterol status | Assessing SREBP pathway activation |
| Proteomics | Protein abundance and interactions | Identifying trafficking machinery changes |
| CRISPR library screening | Genes modifying uptake or trafficking | Discovery of new pathway regulators |
| Live-cell imaging | Vesicle dynamics and receptor recycling | Kinetic analysis of endocytosis |
| Electron microscopy | Ultrastructure of coated and uncoated vesicles | Confirming vesicle identity |
Imaging receptor-mediated uptake and cholesterol distribution
Fluorescence and electron microscopy can visualize receptor-ligand internalization and cholesterol-rich membrane domains. Filipin staining revealed cholesterol complexes in uncoated vesicles derived from coated vesicles during LDL endocytosis, providing ultrastructural evidence for cholesterol reorganization. Live-cell imaging of tagged receptors supports kinetic analysis of GO:0090118.
Lipidomics and biochemical cholesterol assays
Mass spectrometry and enzymatic cholesterol assays quantify free and esterified cholesterol after uptake, revealing how much cargo reaches the endoplasmic reticulum and other organelles. Sphingomyelin measurement is also informative because sphingomyelin influences cholesterol organization and endocytic sorting.
Transcriptional and proteomic readouts of sterol status
Cholesterol delivered by endocytosis feeds back on SREBP-controlled transcription and on the abundance of cholesterol-handling proteins. RNA-seq and proteomics can therefore report pathway activity and identify compensatory changes after CRISPR perturbation.
Genetic screening for trafficking regulators
CRISPR knockout and activation screens coupled to cholesterol reporters or lipid stains can identify genes that modify receptor-mediated endocytosis and post-endosomal cholesterol transport. Such screens help assign function to uncharacterized candidate genes in the pathway.
How CRISPR Can Be Used to Study GO:0090118 receptor-mediated endocytosis involved in cholesterol transport
Knockout
CRISPR knockout of LDLR, ARH, or NPC1 provides clean loss-of-function models to test whether a gene is required for receptor-mediated cholesterol uptake or post-endosomal trafficking. Knockout cells can be challenged with fluorescent LDL and cholesterol assays to quantify defects.
Point Mutation
Point-mutation knock-in allows precise modeling of patient variants in LDLR, PCSK9, or NPC1 without confounding effects of complete gene loss. These models are valuable for testing whether a specific amino acid change alters receptor binding, internalization, or cholesterol egress.
Knock-in
Tagged knock-in of receptors or trafficking proteins enables visualization and affinity purification under endogenous regulatory control. This approach preserves physiological expression levels while adding a functional tag for imaging or proteomics.
Overexpression
Overexpression of LDLR, PCSK9, or cholesterol trafficking proteins can amplify pathway activity or mimic gain-of-function states. Inducible systems help avoid adaptation and allow dose-dependent analysis of cholesterol delivery.
How EDITGENE Supports receptor-mediated endocytosis involved in cholesterol transport Research
Researchers studying receptor-mediated endocytosis involved in cholesterol transport-related genes often need to determine whether a candidate gene is causally involved in LDL uptake, endosomal sorting, or post-endosomal cholesterol trafficking. EDITGENE provides CRISPR-based cell model services that enable such causal tests with reproducible, publication-ready reagents.
Contact EDITGENE today to design your custom CRISPR model for receptor-mediated endocytosis involved in cholesterol transport research.
Frequently Asked Questions About receptor-mediated endocytosis involved in cholesterol transport
What is GO:0090118?
GO:0090118 is the Gene Ontology term for receptor-mediated endocytosis involved in cholesterol transport, a biological process in which cells internalize cholesterol-carrying ligands through surface receptors and deliver cholesterol to intracellular compartments.
What genes are involved in receptor-mediated endocytosis involved in cholesterol transport?
Key genes include LDLR, APOB, PCSK9, ARH, CLTC, NPC1, NPC2, SCAP, SREBF2, and RAB7A, among others.
What is the role of LDLR in cholesterol uptake?
LDLR binds LDL at the plasma membrane and initiates receptor-mediated endocytosis, delivering cholesterol to endosomes and lysosomes for intracellular transport.
How does cholesterol move after endocytosis?
After internalization, cholesterol is processed in endosomes and lysosomes and then trafficked to the endoplasmic reticulum and other organelles via vesicular and non-vesicular routes.
Why is receptor-mediated endocytosis of LDL important in atherosclerosis?
Endothelial transcytosis of LDL across the artery wall contributes to cholesterol accumulation in the intima, a key step in atherosclerosis.
Can pathogens use LDL receptor-mediated endocytosis?
Yes, Toxoplasma gondii exploits host LDLR-mediated endocytosis to acquire cholesterol from the host cell.
What diseases are linked to defects in this pathway?
Familial hypercholesterolemia, atherosclerosis, and lysosomal cholesterol trafficking disorders such as NPC disease are linked to defects in this pathway.
How can I study receptor-mediated endocytosis involved in cholesterol transport in the lab?
Common methods include fluorescent LDL uptake assays, filipin staining, lipidomics, RNA-seq, proteomics, and CRISPR knockout or knock-in models.
What is the difference between LDLR and PCSK9 in this pathway?
LDLR is the receptor that mediates uptake, while PCSK9 regulates LDLR availability by promoting its degradation, thereby modulating pathway activity.
What CRISPR models are useful for studying GO:0090118?
Knockout, point-mutation knock-in, tagged knock-in, and overexpression models of LDLR, ARH, NPC1, and related genes are widely used to dissect this pathway.
Conclusion
GO:0090118, receptor-mediated endocytosis involved in cholesterol transport, is a central biological process that connects extracellular cholesterol carriers to intracellular lipid homeostasis. Its canonical LDLR pathway is essential for cholesterol delivery and is implicated in atherosclerosis, familial hypercholesterolemia, and lysosomal trafficking disorders. Continued research using CRISPR models, imaging, and lipidomics will refine our understanding of how this pathway is regulated and how it can be targeted therapeutically.
References
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