GO:1990771 clathrin-dependent extracellular exosome endocytosis: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1990771 describes the clathrin-mediated endocytosis of extracellular exosomes, a specific route by which recipient cells internalize exosomes [1,5].
• Exosome uptake is cell-type dependent and can involve multiple endocytic pathways, with clathrin-dependent mechanisms prominent in endothelial cells and some cancer cells [3,5,8].
• Key molecular players include clathrin heavy chain (CLTC), adaptor protein 2 (AP2), dynamin (DNM), and tetraspanins such as CD63 that mark exosomes [4,5].
• Clathrin-dependent exosome endocytosis influences cancer progression, immune modulation, and neurodegeneration by delivering proteins, lipids, and nucleic acids [1,3].
• Experimental dissection requires combining uptake inhibitors, colocalization imaging, and genetic perturbation (e.g., CRISPR knockout of CLTC or AP2 subunits) [5,8].
• EDITGENE provides CRISPR knockout, point-mutation, knock-in, overexpression, and library screening services to study genes involved in this pathway.
Description
Extracellular exosomes are small membrane vesicles released by cells and taken up by recipient cells, a process critical for intercellular communication. One specific route of exosome internalization is clathrin-dependent extracellular exosome endocytosis, annotated as GO:1990771, which describes the clathrin-mediated endocytosis of an extracellular exosome [1,5]. This process is distinct from other uptake mechanisms such as macropinocytosis, phagocytosis, or caveolin-mediated endocytosis, and its prevalence varies with cell type and exosome composition [3,5]. Understanding this pathway is essential for researchers studying vesicle trafficking, cancer metastasis, immune regulation, and neurodegenerative disease propagation [1,3,8]. The molecular machinery includes clathrin triskelia, adaptor proteins, and dynamin, which together mediate vesicle formation and scission. Tetraspanins like CD63 are enriched on exosomes and can influence their uptake. Because exosomes carry bioactive cargo, clathrin-dependent endocytosis can reprogram recipient cells, making it a target for therapeutic intervention and a subject of intense investigation [2,6,7].
clathrin-dependent extracellular exosome endocytosis At A Glance
| GO ID | GO:1990771 |
|---|---|
| GO term | clathrin-dependent extracellular exosome endocytosis |
| Ontology | biological_process |
| Synonym | clathrin-mediated extracellular exosome endocytosis, exosome related |
| Major function | Internalization of extracellular exosomes via clathrin-coated vesicles |
| Cellular location | Plasma membrane, clathrin-coated pit, endocytic vesicle |
| Key molecular players | Clathrin heavy chain (CLTC), AP2 complex, dynamin (DNM), tetraspanins (CD63) |
| Related processes | Endocytosis, vesicle trafficking, exosome uptake |
| Disease relevance | Cancer, neurodegeneration, metabolic disorders |
What Is GO:1990771?
GO:1990771 (clathrin-dependent extracellular exosome endocytosis) is a biological process defined as the clathrin-mediated endocytosis of an extracellular exosome. In this process, an exosome that is present outside a cell is internalized through the formation of clathrin-coated pits and vesicles, involving the coordinated action of clathrin, adaptor proteins, and dynamin. This term specifically captures the clathrin-dependent route, distinguishing it from other endocytic mechanisms that may also internalize exosomes.
Why Is clathrin-dependent extracellular exosome endocytosis Important in Cell Biology?
Clathrin-dependent extracellular exosome endocytosis is a fundamental mechanism by which cells communicate and acquire new molecular information from their environment. It enables the delivery of proteins, lipids, and nucleic acids from donor to recipient cells, influencing processes such as tumor progression, immune responses, and neuronal function [3,8]. Dysregulation of this pathway has been implicated in cancer metastasis, where exosomes can transfer oncogenic signals, and in neurodegenerative diseases, where exosomes may spread pathological proteins [1,6]. Moreover, understanding this specific endocytic route is crucial for developing exosome-based therapeutics, as efficient cargo delivery depends on the uptake mechanism [2,7]. Researchers studying this process can identify therapeutic targets and biomarkers, making GO:1990771 a key annotation for both basic and translational research.
• Mediates intercellular transfer of oncogenic proteins and RNAs, promoting tumor growth and metastasis [1,3].
• Facilitates immune cell communication and modulation, affecting immune responses.
• Contributes to the spread of pathological proteins in neurodegenerative diseases.
• Determines the efficiency of exosome-based drug delivery systems [2,7].
• Cell-type specific, influencing how different tissues respond to exosomes [3,5,8].
• Involved in metabolic disorders such as insulin resistance and hyperglycemia.
• Provides a target for inhibiting exosome uptake in disease contexts.
• Essential for understanding vesicle trafficking and membrane dynamics.
• Helps explain differential uptake of exosomes from various cell sources.
• Guides the design of CRISPR screens to identify novel regulators of exosome uptake [5,8].
What Happens During clathrin-dependent extracellular exosome endocytosis?
Exosome binding to the recipient cell surface
In simple terms: The exosome first sticks to the outside of the cell.
The initial step involves the interaction of the exosome with the recipient cell plasma membrane. This can be mediated by adhesion molecules, tetraspanins, or other receptors, and is a prerequisite for clathrin-dependent uptake [1,4]. The binding is often cell-type specific and can determine the subsequent endocytic route.
Recruitment of clathrin and adaptor proteins
In simple terms: The cell assembles a protein coat around the exosome to pull it inside.
Upon binding, clathrin triskelia are recruited to the plasma membrane, along with adaptor protein complex 2 (AP2) and other accessory proteins. This leads to the formation of a clathrin-coated pit that invaginates around the exosome. The process requires the GTPase dynamin for vesicle scission.
Vesicle formation and scission
In simple terms: The coated pit pinches off to form a vesicle inside the cell.
The clathrin-coated pit deepens and eventually pinches off from the plasma membrane, forming a clathrin-coated vesicle containing the exosome. Dynamin mediates the scission event, and the vesicle is then uncoated and trafficked to endosomal compartments.
Intracellular trafficking and cargo release
In simple terms: The vesicle moves inside the cell and releases the exosome contents.
After internalization, the vesicle loses its clathrin coat and fuses with early endosomes. The exosome cargo can then be delivered to the cytosol or other organelles, influencing recipient cell behavior [1,4]. This step is critical for functional outcomes such as signal transduction or gene regulation.
Key Genes Involved in GO:1990771 clathrin-dependent extracellular exosome endocytosis
The following genes and proteins are key players in clathrin-dependent extracellular exosome endocytosis, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| CLTC | Clathrin heavy chain; forms the clathrin coat | Essential for clathrin-mediated endocytosis; knockout inhibits exosome uptake |
| CLTA | Clathrin light chain; regulates coat assembly | Modulates clathrin dynamics; potential target for uptake inhibition |
| AP2B1 | AP2 beta subunit; cargo recognition | Required for clathrin-coated pit formation; knockdown reduces exosome internalization |
| AP2A1 | AP2 alpha subunit; membrane recruitment | Involved in exosome binding and uptake; can be targeted by CRISPR |
| DNM1 | Dynamin 1; vesicle scission | GTPase essential for pinching off clathrin-coated vesicles |
| DNM2 | Dynamin 2; ubiquitously expressed | Mediates scission in non-neuronal cells; affects exosome uptake |
| CD63 | Tetraspanin; exosome marker | Influences exosome biogenesis and uptake; can modulate clathrin-dependent internalization |
| CD9 | Tetraspanin; exosome marker | Participates in exosome adhesion and uptake |
| CD81 | Tetraspanin; exosome marker | May facilitate exosome binding to recipient cells |
| ITGB1 | Integrin beta 1; adhesion | Mediates exosome binding to extracellular matrix and cells |
| HSPA8 | Hsc70; chaperone | Involved in clathrin uncoating and endosomal trafficking |
| EPS15 | EGFR pathway substrate 15; adaptor | Links cargo to clathrin coat; affects uptake efficiency |
| EPN1 | Epsin 1; adaptor | Promotes membrane curvature and clathrin recruitment |
| PICALM | Phosphatidylinositol binding clathrin assembly protein | Regulates clathrin-coated pit formation; implicated in Alzheimer's disease |
| BIN1 | Bridging integrator 1; membrane curvature | Facilitates clathrin-mediated endocytosis; linked to neurodegeneration |
| RAB5A | Early endosome marker | Regulates endosomal trafficking after exosome uptake |
| RAB7A | Late endosome marker | Involved in exosome degradation or recycling |
| VPS35 | Retromer component | Affects endosomal sorting of internalized exosomes |
How Is clathrin-dependent extracellular exosome endocytosis Regulated?
The process of clathrin-dependent extracellular exosome endocytosis is regulated at multiple levels. Cell-type specific expression of receptors and adaptor proteins determines the efficiency of uptake [3,5]. Post-translational modifications, such as phosphorylation of clathrin and AP2, can modulate coat assembly. Additionally, the lipid composition of the plasma membrane and exosome membrane influences binding and internalization. Signaling pathways, including those involving PI3K/Akt and mTOR, may indirectly affect endocytic capacity by altering membrane dynamics and energy status [1,7]. In conditions of hyperglycemia and insulin resistance, exosome production and internalization are altered, suggesting metabolic regulation. Furthermore, the presence of specific tetraspanins on exosomes can dictate preferential uptake routes.
clathrin-dependent extracellular exosome endocytosis and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| CLTC | Cancer progression, metastasis | CRISPR knockout in cancer cell lines, uptake assays |
| PICALM | Alzheimer's disease | Knock-in of risk variants in iPSC-derived neurons |
| BIN1 | Neurodegeneration | Overexpression or knockout in neuronal cultures |
| CD63 | Cancer, immune modulation | Knockout in exosome-producing cells, tracking uptake |
| DNM2 | Metabolic disorders | Point mutation of GTPase domain, uptake studies |
Cancer
Clathrin-dependent exosome endocytosis facilitates the transfer of oncogenic proteins and RNAs between cancer cells and stromal cells, promoting tumor growth, angiogenesis, and metastasis [1,3]. For example, exosomes from cancer cells can be taken up by endothelial cells via clathrin-mediated pathways, stimulating angiogenesis. Targeting this uptake mechanism may reduce cancer progression.
Neurodegenerative diseases
In neurodegenerative disorders such as Alzheimer's and Parkinson's diseases, exosomes can spread misfolded proteins like amyloid-beta and alpha-synuclein between neurons. Clathrin-dependent endocytosis is one route for this propagation, contributing to disease progression. Proteins like PICALM and BIN1, involved in clathrin-mediated endocytosis, are associated with Alzheimer's disease risk.
Metabolic disorders
Hyperglycemia and insulin resistance alter the production and internalization of extracellular vesicles, including exosomes. This can affect intercellular communication in metabolic tissues, contributing to diabetes complications. The clathrin-dependent pathway may be modulated under these conditions, offering a potential target for therapeutic intervention.
Infectious diseases
Exosomes from parasitic worms, such as Opisthorchis felineus, can be taken up by human cholangiocytes, potentially via clathrin-dependent mechanisms, influencing host-pathogen interactions. Understanding this uptake can inform strategies to block parasite-derived vesicle entry.
From clathrin-dependent extracellular exosome endocytosis-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does CLTC knockout inhibit exosome uptake? | CRISPR knockout of CLTC in recipient cells, followed by fluorescent exosome uptake assay |
| What is the role of AP2B1 in exosome internalization? | Knockout or knockdown of AP2B1, colocalization with exosome markers |
| Can a point mutation in DNM2 affect scission? | Knock-in of dynamin mutants, live-cell imaging |
| How does CD63 overexpression affect uptake? | Overexpression of tagged CD63 in donor cells, tracking exosome transfer |
| Which genes regulate clathrin-dependent exosome endocytosis? | Genome-wide CRISPR library screening with exosome uptake readout [5,8] |
| Does PICALM risk variant alter endocytosis? | Knock-in of Alzheimer's-associated PICALM variant in iPSCs |
How to Study the clathrin-dependent extracellular exosome endocytosis Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Flow cytometry | Percentage of cells internalizing fluorescent exosomes | Quantify uptake efficiency across cell types |
| Confocal microscopy | Colocalization of exosomes with clathrin/AP2 | Confirm clathrin-dependent route |
| CRISPR knockout | Loss-of-function effect on uptake | Identify essential genes |
| Proteomics | Protein composition of exosomes and uptake machinery | Discover novel regulators [6,8] |
| Live-cell imaging | Dynamics of clathrin-coated pit formation | Visualize real-time uptake |
| RNA-seq | Transcriptional changes after exosome uptake | Assess downstream signaling |
| CRISPR library screen | Genome-wide identification of regulators | Unbiased discovery of uptake genes [5,8] |
| Western blot | Validation of knockout efficiency | Confirm gene editing |
Fluorescent exosome uptake assays
Exosomes are labeled with lipophilic dyes (e.g., PKH26) or fluorescent proteins, and incubated with recipient cells. Uptake is quantified by flow cytometry or confocal microscopy. Co-localization with clathrin markers confirms clathrin-dependent internalization [5,8].
Proteomic profiling of exosomes and recipient cells
Mass spectrometry can identify proteins enriched in exosomes and those recruited to the uptake site. Comparative proteomics of exosomes from different cell sources reveals cargo that may influence uptake mechanisms [6,8].
Genetic perturbation with CRISPR
CRISPR knockout of candidate genes (e.g., CLTC, AP2B1, DNM2) followed by uptake assays can establish causality. Point mutations can dissect domain-specific functions, and knock-in of tags enables tracking.
Live-cell imaging
Total internal reflection fluorescence (TIRF) microscopy and spinning-disk confocal imaging allow real-time visualization of clathrin-coated pit formation and exosome internalization. Fluorescently tagged clathrin and exosomes are used.
How CRISPR Can Be Used to Study GO:1990771 clathrin-dependent extracellular exosome endocytosis
Knockout
CRISPR knockout of genes such as CLTC, AP2B1, or DNM2 in recipient cells can abolish or reduce clathrin-dependent exosome endocytosis. This approach provides direct evidence for gene function and is widely used to validate uptake mechanisms.
Point Mutation
Introducing specific point mutations (e.g., in the GTPase domain of DNM2) allows dissection of domain-specific functions without completely eliminating protein expression. This is useful for studying dynamic processes like vesicle scission.
Knock-in
Knock-in of fluorescent tags (e.g., GFP) into endogenous loci of clathrin or tetraspanins enables real-time tracking of the uptake machinery in live cells. Knock-in of disease-associated variants (e.g., PICALM) can model altered endocytosis.
Overexpression
Overexpression of candidate genes (e.g., CD63, CLTC) can enhance or saturate the pathway, helping to identify rate-limiting steps. It is also used to study the effect of excess protein on exosome uptake.
How EDITGENE Supports clathrin-dependent extracellular exosome endocytosis Research
Researchers studying clathrin-dependent extracellular exosome endocytosis-related genes often need to determine whether a candidate gene is causally involved in the uptake process or is merely correlated. EDITGENE provides a comprehensive suite of CRISPR-based services to enable precise genetic manipulation and functional validation.
Contact EDITGENE today to design your custom CRISPR model for clathrin-dependent extracellular exosome endocytosis research.
Frequently Asked Questions About clathrin-dependent extracellular exosome endocytosis
What is clathrin-dependent extracellular exosome endocytosis?
It is the process by which cells internalize extracellular exosomes through clathrin-coated vesicles, annotated as GO:1990771 [1,5].
What genes are involved in clathrin-dependent extracellular exosome endocytosis?
Key genes include CLTC, AP2B1, AP2A1, DNM1, DNM2, CD63, and PICALM, among others [4,5].
How is clathrin-dependent exosome uptake different from other pathways?
It specifically requires the clathrin coat and dynamin for vesicle formation, unlike macropinocytosis or caveolin-mediated uptake [1,5].
Which diseases are associated with clathrin-dependent exosome endocytosis?
Cancer, neurodegenerative diseases, metabolic disorders, and infectious diseases [1,3,6,7].
What methods are used to study clathrin-dependent exosome endocytosis?
Fluorescent uptake assays, confocal microscopy, CRISPR knockout, proteomics, and live-cell imaging [5,6,8].
Can CRISPR be used to study this pathway?
Yes, CRISPR knockout of CLTC or AP2 subunits can abolish uptake, and knock-in of tags enables tracking.
What is the role of CD63 in exosome endocytosis?
CD63 is a tetraspanin enriched on exosomes that can influence their biogenesis and uptake by recipient cells.
Is clathrin-dependent exosome uptake cell-type specific?
Yes, the efficiency and reliance on clathrin vary among cell types, such as endothelial cells versus fibroblasts [3,5,8].
How does dynamin function in this process?
Dynamin is a GTPase that mediates scission of clathrin-coated vesicles from the plasma membrane.
What services does EDITGENE offer for studying this pathway?
EDITGENE provides CRISPR knockout, point mutation, knock-in, overexpression, library screening, and bioinformatics services.
Conclusion
Clathrin-dependent extracellular exosome endocytosis (GO:1990771) is a specialized endocytic route critical for intercellular communication and disease progression. Understanding its molecular players and regulation offers opportunities for therapeutic intervention in cancer, neurodegeneration, and metabolic disorders. EDITGENE's CRISPR services empower researchers to dissect this pathway with precision and speed.
References
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- 2. Tran PHL et al.. 2019. Aspirin-loaded nanoexosomes as cancer therapeutics.. Int J Pharm 572:118786 PMID: 31669214
- 3. Horibe S et al.. 2018. Mechanism of recipient cell-dependent differences in exosome uptake.. BMC Cancer 18(1):47 PMID: 29306323
- 4. Pols MS et al.. 2009. Trafficking and function of the tetraspanin CD63.. Exp Cell Res 315(9):1584-92 PMID: 18930046
- 5. Banizs AB et al.. 2018. Endocytosis Pathways of Endothelial Cell Derived Exosomes.. Mol Pharm 15(12):5585-5590 PMID: 30351959
- 6. Pakharukova MY et al.. 2023. Proteomic characterization of Opisthorchis felineus exosome-like vesicles and their uptake by human cholangiocytes.. J Proteomics 283-284:104927 PMID: 37225040
- 7. Yunusova NV et al.. 2021. [Production and internalization of extracellular vesicules in normal and under conditions of hyperglycemia and insulin resistance].. Biomed Khim 67(6):465-474 PMID: 34964440
- 8. Zhang S et al.. 2024. Divergent Proteomic Profiles and Uptake Mechanisms of Exosomes Derived from Human Dental Pulp Stem Cells, Endothelial Cells, and Fibroblasts.. Mol Pharm 21(12):6353-6362 PMID: 39535266
