GO:0097020 COPII receptor activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0097020 COPII receptor activity describes the molecular function of binding cargo and coat adaptors to deliver proteins into COPII transport vesicles.
• COPII receptors such as TMED7 and related p24 family proteins act as adaptors that couple cargo selection to vesicle formation at endoplasmic reticulum exit sites.
• The ufmylation cascade controls COPII recruitment and anterograde transport of nascent G protein-coupled receptors, linking post-translational modification to receptor activity.
• Endoplasmic reticulum exit sites are segregated for secretion based on cargo size, and COPII receptor activity contributes to this selectivity.
• Dysregulation of COPII receptor activity is implicated in cancer progression, inflammatory signaling, and metabolic disease.
• CRISPR knockout, point mutation, knock-in, and overexpression models enable causal dissection of COPII receptor genes in human cells.
Description
COPII receptor activity (GO:0097020) is a molecular function that enables a membrane-spanning protein to bind cargo molecules and simultaneously engage COPII coat adaptors, thereby concentrating soluble and membrane proteins into nascent COPII vesicles. This activity is essential for the first step of the secretory pathway, the export of proteins from the endoplasmic reticulum (ER) to the Golgi apparatus. Researchers studying ER-to-Golgi trafficking rely on this term to annotate proteins that function as cargo receptors rather than as structural coat components or soluble cargo. The functional importance of COPII receptor activity extends beyond basic cell biology. Mutations or altered expression of COPII receptor proteins have been linked to inflammatory signaling, cancer cell biology, and metabolic regulation. For example, RHBDL4-triggered downregulation of the COPII adaptor protein TMED7 suppresses TLR4-mediated inflammatory signaling, demonstrating that COPII receptor activity directly modulates immune responses. In cancer, targeting ER/Golgi vesicle trafficking, including COPII-dependent steps, can reprogram pancreatic cancer-associated fibroblasts. These findings position COPII receptor activity as a central node connecting protein secretion to disease-relevant signaling pathways.
COPII receptor activity At A Glance
| GO ID | GO:0097020 |
|---|---|
| GO term | COPII receptor activity |
| Ontology | molecular_function |
| Synonym | None listed in QuickGO |
| Major function | Binding cargo and coat adaptors to deliver proteins into COPII transport vesicles |
| Cellular location | Membrane of the endoplasmic reticulum or vesicle membrane |
| Biological context | ER-to-Golgi anterograde transport, cargo selection, secretory pathway |
| Example proteins | TMED7, p24 family proteins, and other COPII cargo receptors |
| Related processes | COPII vesicle formation, ER exit site organization, GPCR sorting |
What Is GO:0097020?
According to the Gene Ontology, COPII receptor activity (GO:0097020) is defined as binding specifically to a substance (cargo) to deliver it to a COPII transport vesicle. Cargo receptors span a membrane (either the plasma membrane or a vesicle membrane), binding simultaneously to cargo molecules and coat adaptors, to efficiently recruit soluble proteins to nascent vesicles. In practice, this means the receptor acts as a physical bridge: one domain or surface recognizes the cargo, while another recruits COPII coat proteins such as SEC23/SEC24 or SEC13, ensuring that the cargo is packaged into a vesicle that buds from the ER.
Why Is COPII receptor activity Important in Cell Biology?
COPII receptor activity is important because it determines which proteins leave the endoplasmic reticulum and at what rate, thereby controlling the composition of the secretory pathway and the cell surface proteome. Defects in this activity can cause cargo retention, ER stress, and altered signaling, with consequences for inflammation, cancer, and metabolic disease.
• Controls selective export of proteins from the endoplasmic reticulum to the Golgi.
• Enables efficient packaging of soluble and membrane cargo into COPII vesicles.
• Modulates inflammatory signaling through proteins such as TMED7.
• Influences cancer cell biology and tumor microenvironment reprogramming.
• Required for proper sorting and anterograde transport of nascent GPCRs.
• Links post-translational modifications such as ufmylation to ER export.
• Provides a mechanism for cargo size-dependent segregation at ER exit sites.
• Represents a potential therapeutic target in diseases with secretory pathway dysfunction.
What Happens During COPII receptor activity?
Cargo recognition at the endoplasmic reticulum
In simple terms: The receptor grabs the cargo protein inside the ER.
COPII receptor activity begins when a membrane-spanning receptor binds a specific cargo molecule in the endoplasmic reticulum lumen or membrane. This binding is selective and ensures that only appropriate proteins are concentrated for export. The receptor can recognize soluble cargo or membrane cargo, and this interaction is the first step in delivering the cargo to a COPII vesicle.
Recruitment of COPII coat adaptors
In simple terms: The receptor calls over the vesicle-building machinery.
After binding cargo, the receptor simultaneously engages COPII coat adaptors such as SEC23/SEC24 and SEC13. This dual binding couples cargo selection to vesicle formation, allowing the nascent vesicle to concentrate the cargo efficiently. The ufmylation cascade has been shown to control COPII recruitment and anterograde transport of nascent GPCRs, indicating that adaptor recruitment is a regulated step.
Vesicle budding and cargo sorting
In simple terms: The vesicle pinches off with the cargo inside.
Once the receptor has bound both cargo and coat adaptors, the COPII coat polymerizes and deforms the membrane, leading to vesicle budding. Endoplasmic reticulum exit sites are segregated for secretion based on cargo size, and COPII receptor activity contributes to this size-dependent sorting. This ensures that different cargoes are packaged into distinct vesicles for efficient transport.
Delivery to the Golgi and receptor recycling
In simple terms: The cargo is dropped off and the receptor can be reused.
After the COPII vesicle fuses with the Golgi apparatus, the cargo is released and the receptor may be recycled back to the ER. This cycle maintains the steady-state distribution of the receptor and allows repeated rounds of cargo transport. Disruption of this cycle can lead to cargo retention and altered signaling.
Key Genes Involved in GO:0097020 COPII receptor activity
The following genes and proteins are experimentally linked to COPII receptor activity or its regulation in the secretory pathway.
| Gene | Major Role | Research Relevance |
|---|---|---|
| TMED7 | COPII adaptor protein and cargo receptor | Downregulation suppresses TLR4-mediated inflammatory signaling |
| SEC13 | COPII coat component and receptor-associated factor | Targeted by bufalin in breast cancer bone metastasis |
| SEC23 | COPII coat adaptor that binds cargo receptors | Core component of COPII vesicle formation |
| SEC24 | COPII coat adaptor that binds cargo receptors | Selects cargo for ER export |
| SEC31 | Outer COPII coat component | Required for vesicle budding |
| SAR1 | Small GTPase that initiates COPII assembly | Recruits coat proteins to ER exit sites |
| UFM1 | Ubiquitin-like modifier | Controls COPII recruitment and GPCR sorting |
| UBA5 | Ufmylation E1 enzyme | Regulates COPII-dependent transport |
| UFC1 | Ufmylation E2 enzyme | Regulates COPII-dependent transport |
| UFSP2 | Ufmylation protease | Modulates COPII recruitment |
| MYOF | ER/Golgi vesicle trafficking protein | Targeting myoferlin reprograms pancreatic cancer-associated fibroblasts |
| SCAP | ER membrane protein involved in lipid regulation | Degradation affects metabolic disease models |
| TFEB | Transcription factor regulating lysosomal and antioxidant genes | FACT complex facilitates its expression |
| TFE3 | Transcription factor related to TFEB | FACT complex facilitates its expression |
| FACT complex | Chromatin regulator | Facilitates expression of lysosomal and antioxidant genes |
| RHBDL4 | Rhomboid protease | Triggers downregulation of TMED7 |
| TLR4 | Immune receptor | Inflammatory signaling modulated by TMED7 |
How Is COPII receptor activity Regulated?
COPII receptor activity is regulated at multiple levels. The ufmylation cascade, including UBA5, UFC1, and UFSP2, controls COPII recruitment and anterograde transport of nascent GPCRs, linking post-translational modification to receptor function. RHBDL4-triggered downregulation of TMED7 provides another regulatory mechanism, in which proteolytic cleavage reduces COPII adaptor availability and suppresses TLR4-mediated inflammatory signaling. Cargo size also influences segregation at ER exit sites, suggesting that receptor activity is tuned to the physical properties of cargo. Additionally, metabolic and autophagy-related pathways can influence ER-to-Golgi trafficking, as shown by SCAP degradation and lysosomal regulation.
COPII receptor activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SEC13 | Breast cancer bone metastasis | Knockout or point mutation in breast cancer cell lines |
| TMED7 | TLR4-mediated inflammatory signaling | Knockout or overexpression in macrophage-like cells |
| MYOF | Pancreatic cancer-associated fibroblasts | Knockout or knockdown in fibroblast models |
| SCAP | Obesity, hyperlipidemia, insulin resistance | Knockout or degrader-treated hepatocyte models |
| TFEB/TFE3 | Lysosomal and antioxidant gene regulation | Knockout or overexpression in stress models |
COPII receptor activity in cancer
COPII receptor activity contributes to cancer cell biology and tumor microenvironment remodeling. Bufalin suppresses breast cancer bone metastasis through targeting SEC13-mediated osteoclastogenesis, linking a COPII coat component to metastatic progression. Targeting myoferlin in ER/Golgi vesicle trafficking reprograms pancreatic cancer-associated fibroblasts, indicating that COPII-dependent transport supports tumor-stromal interactions. These findings suggest that COPII receptor activity and associated trafficking proteins are potential therapeutic targets in oncology.
COPII receptor activity in inflammatory signaling
RHBDL4-triggered downregulation of the COPII adaptor protein TMED7 suppresses TLR4-mediated inflammatory signaling, demonstrating that COPII receptor activity directly modulates innate immune responses. This connection implies that dysregulated COPII receptor function could contribute to chronic inflammation or impaired pathogen responses.
COPII receptor activity in metabolic and lysosomal regulation
Metabolic pathways intersect with COPII-dependent trafficking. Discovery of a potent SCAP degrader that ameliorates HFD-induced obesity, hyperlipidemia, and insulin resistance via an autophagy-independent lysosomal pathway highlights the importance of ER-to-Golgi transport in metabolic disease. The FACT complex facilitates expression of lysosomal and antioxidant genes through binding to TFEB and TFE3, further linking secretory pathway regulation to cellular stress responses.
From COPII receptor activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is a COPII receptor gene required for ER export? | CRISPR knockout cell line |
| Does a point mutation alter cargo binding? | CRISPR point mutation knock-in |
| Where does the receptor localize? | Tagged knock-in with fluorescent protein |
| Does overexpression increase secretion? | CRISPR overexpression cell model |
| Which cargoes depend on the receptor? | Knockout followed by proteomics |
| Does the receptor modulate inflammatory signaling? | Knockout in immune cells |
How to Study the COPII receptor activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Fluorescence microscopy | Localization of COPII receptors and cargo | ER exit site imaging |
| Co-immunoprecipitation | Protein-protein interactions | Cargo-receptor binding |
| Mass spectrometry | Cargo and interactor identification | Proteomic profiling |
| Pulse-chase labeling | ER-to-Golgi transport rate | Secretion assays |
| RNA sequencing | Transcriptional changes | Pathway analysis |
| CRISPR knockout | Gene function loss | Causal testing |
| CRISPR knock-in | Tagged or mutant protein expression | Localization and function |
| Bioinformatics | Pathway and network analysis | Data integration |
Imaging ER exit sites and vesicle formation
Fluorescence microscopy of tagged COPII components and cargo receptors allows visualization of ER exit site organization and vesicle budding. Endoplasmic reticulum exit sites are segregated for secretion based on cargo size, and imaging can reveal whether a candidate receptor affects this segregation.
Proteomics and cargo identification
Mass spectrometry-based proteomics can identify cargo proteins that co-purify with a COPII receptor or that are secreted in a receptor-dependent manner. This approach helps define the cargo repertoire and functional consequences of receptor activity.
Functional secretion assays
Pulse-chase metabolic labeling and secreted reporter assays measure the rate of ER-to-Golgi transport. These assays can be combined with CRISPR knockout or overexpression to test whether a gene is required for COPII receptor activity.
Transcriptomic and bioinformatic analysis
RNA sequencing and bioinformatics can reveal transcriptional changes in secretory pathway genes and downstream signaling upon perturbation of COPII receptor activity. Such analyses help link receptor function to broader cellular programs.
How CRISPR Can Be Used to Study GO:0097020 COPII receptor activity
Knockout
CRISPR knockout of COPII receptor genes such as TMED7 or SEC13 can reveal their requirement for ER export and downstream signaling. For example, knockout of TMED7 would test its role in TLR4-mediated inflammatory signaling, while knockout of SEC13 can assess its function in osteoclastogenesis and bone metastasis.
Point Mutation
CRISPR point mutation can be used to disrupt specific cargo-binding or coat-adaptor-binding residues in a COPII receptor. This approach helps separate cargo recognition from coat recruitment and can model disease-associated variants.
Knock-in
Knock-in of fluorescent or epitope tags into endogenous COPII receptor loci enables live-cell imaging and biochemical purification without overexpression artifacts. Tagged knock-in models are valuable for tracking receptor trafficking and recycling.
Overexpression
CRISPR overexpression of a COPII receptor can test whether increased receptor levels enhance secretion or alter signaling. Overexpression of TMED7, for instance, could modulate inflammatory responses, while overexpression of ufmylation components can affect COPII recruitment.
How EDITGENE Supports COPII receptor activity Research
Researchers studying COPII receptor activity-related genes often need to determine whether a candidate gene is causally involved in cargo selection, vesicle formation, or disease-relevant signaling. EDITGENE provides validated CRISPR models and screening services to accelerate this functional dissection.
Contact EDITGENE today to design your custom CRISPR model for COPII receptor activity research.
Frequently Asked Questions About COPII receptor activity
What is COPII receptor activity?
COPII receptor activity (GO:0097020) is a molecular function in which a membrane-spanning protein binds cargo and coat adaptors to deliver the cargo into COPII transport vesicles.
What genes are involved in COPII receptor activity?
Genes include TMED7, SEC13, SEC23, SEC24, SEC31, SAR1, and ufmylation components such as UFM1, UBA5, UFC1, and UFSP2.
What is the GO ID for COPII receptor activity?
The GO ID is GO:0097020.
How is COPII receptor activity regulated?
It is regulated by the ufmylation cascade, proteolytic downregulation of adaptors such as TMED7, and cargo size-dependent segregation at ER exit sites.
Which diseases are linked to COPII receptor activity?
It has been linked to breast cancer bone metastasis, pancreatic cancer-associated fibroblasts, inflammatory signaling, and metabolic disease.
What experimental models are used to study COPII receptor activity?
CRISPR knockout, point mutation, knock-in, overexpression cell models, and imaging or proteomic assays are commonly used.
How does COPII receptor activity affect inflammation?
RHBDL4-triggered downregulation of TMED7 suppresses TLR4-mediated inflammatory signaling, showing that COPII receptor activity modulates immune responses.
Can COPII receptor activity be targeted therapeutically?
Targeting COPII-associated trafficking proteins such as SEC13 and myoferlin has shown effects in cancer models, suggesting therapeutic potential.
What is the role of ufmylation in COPII receptor activity?
The ufmylation cascade controls COPII recruitment, anterograde transport, and sorting of nascent GPCRs at the ER.
How do I study COPII receptor activity in the lab?
Use CRISPR knockout or overexpression combined with imaging, proteomics, and secretion assays to measure cargo transport and signaling.
Conclusion
COPII receptor activity (GO:0097020) is a fundamental molecular function that couples cargo recognition to COPII vesicle formation, ensuring selective protein export from the endoplasmic reticulum. Its regulation by ufmylation, proteolysis, and cargo size highlights the complexity of ER-to-Golgi trafficking. Dysregulation of COPII receptor activity is implicated in cancer, inflammation, and metabolic disease, making it a compelling area for functional genomics research. CRISPR-based models and bioinformatic approaches provide powerful tools to dissect these mechanisms and identify therapeutic targets.
References
- 1. Li Z et al.. 2026. Bufalin suppresses breast cancer bone metastasis through targeting SEC13-mediated osteoclastogenesis.. Phytomedicine 159:158474 PMID: 42365695
- 2. Zheng ZG et al.. 2021. Discovery of a potent SCAP degrader that ameliorates HFD-induced obesity, hyperlipidemia and insulin resistance via an autophagy-independent lysosomal pathway.. Autophagy 17(7):1592-1613 PMID: 32432943
- 3. Knopf JD et al.. 2024. RHBDL4-triggered downregulation of COPII adaptor protein TMED7 suppresses TLR4-mediated inflammatory signaling.. Nat Commun 15(1):1528 PMID: 38453906
- 4. Saxena S et al.. 2024. Endoplasmic reticulum exit sites are segregated for secretion based on cargo size.. Dev Cell 59(19):2593-2608.e6 PMID: 38991587
- 5. Xu X et al.. 2024. The ufmylation cascade controls COPII recruitment, anterograde transport, and sorting of nascent GPCRs at ER.. Sci Adv 10(25):eadm9216 PMID: 38905340
- 7. Peiffer R et al.. 2025. Targeting myoferlin in ER/Golgi vesicle trafficking reprograms pancreatic cancer-associated fibroblasts.. EMBO J 44(22):6425-6465 PMID: 41062852
- 8. Jeong E et al.. 2022. The FACT complex facilitates expression of lysosomal and antioxidant genes through binding to TFEB and TFE3.. Autophagy 18(10):2333-2349 PMID: 35230915
