GO:0140506 endoplasmic reticulum-autophagosome adaptor activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0140506 describes a molecular function in which a protein physically bridges the endoplasmic reticulum (ER) membrane and the autophagosome membrane during reticulophagy.
• The term is a molecular_function in the Gene Ontology and is distinct from general autophagy cargo receptors because it specifically anchors two organelles together.
• STING (TMEM173) is the best-characterized ER-resident adaptor that traffics to autophagosomes and can act as an ER-autophagosome adaptor during reticulophagy [1,5].
• Reticulophagy mediated by ER-autophagosome adaptors is a primordial function of the cGAS-STING pathway and is conserved from invertebrates to humans.
• Dysregulation of ER-autophagosome adaptor activity is linked to inflammatory diseases, including inflammatory bowel disease (IBD), through altered autophagy-microbiota crosstalk [2,6].
• CRISPR knockout, point-mutation, knock-in and overexpression models are essential to test whether candidate adaptors are causally required for ER-autophagosome tethering [5,8].
Description
GO:0140506, endoplasmic reticulum-autophagosome adaptor activity, is a Gene Ontology molecular_function term that defines the binding activity of a molecule that brings together an ER membrane and an autophagosome membrane during reticulophagy. In practical terms, this activity is the molecular glue that tethers the endoplasmic reticulum to the forming or mature autophagosome, allowing selective degradation of ER fragments. The term is therefore central to organelle quality control and to the broader field of selective autophagy. The best-characterized example of an ER-autophagosome adaptor is STING (encoded by TMEM173), an ER-resident protein that traffics through the secretory pathway and can act as an ER adaptor for innate immune signalling and for autophagy induction [1,5]. STING trafficking from the ER to autophagosomes is a primordial function of the cGAS-STING pathway, and this trafficking is required for autophagy induction in response to cytosolic DNA. Because the adaptor activity physically links two distinct organelles, its study requires methods that resolve membrane contact sites, autophagosome biogenesis and ER turnover simultaneously. Researchers studying GO:0140506 are typically interested in how cells decide which ER subdomains are degraded, how adaptors are regulated, and how defects in this process contribute to inflammatory and metabolic disease [2,6].
endoplasmic reticulum-autophagosome adaptor activity At A Glance
| GO ID | GO:0140506 |
|---|---|
| GO term | endoplasmic reticulum-autophagosome adaptor activity |
| Ontology | molecular_function |
| Synonym | autophagosome-endoplasmic reticulum anchor; autophagosome-ER anchor; ER-autophagosome anchor |
| Definition | The binding activity of a molecule that brings together an ER membrane and an autophagosome membrane during reticulophagy. |
| Major function | Physical tethering of ER and autophagosome membranes to enable selective ER degradation (reticulophagy). |
| Representative adaptor | STING (TMEM173), an ER-resident adaptor that traffics to autophagosomes and supports autophagy induction. |
| Related process | Selective autophagy / reticulophagy; organelle quality control. |
| Disease relevance | Inflammatory bowel disease, innate immune signalling disorders and autophagy-related inflammatory diseases. |
What Is GO:0140506?
In our own words, GO:0140506 (endoplasmic reticulum-autophagosome adaptor activity) is the function of a protein that simultaneously binds an ER membrane and an autophagosome membrane, thereby anchoring the two organelles together during reticulophagy. This is a binding/adaptor activity rather than a catalytic activity: the protein does not cleave or modify a substrate but instead provides a physical bridge that enables selective ER sequestration into autophagosomes. The QuickGO definition specifies that the activity occurs during reticulophagy, the selective autophagic degradation of ER. Synonyms include autophagosome-endoplasmic reticulum anchor, autophagosome-ER anchor and ER-autophagosome anchor, all of which emphasize the tethering role.
Why Is endoplasmic reticulum-autophagosome adaptor activity Important in Cell Biology?
GO:0140506 matters because it defines the molecular step that commits ER fragments to autophagic destruction, and this step is a point of convergence for innate immunity, organelle quality control and inflammatory disease [5,6]. STING is an ER adaptor that facilitates innate immune signalling and also traffics to autophagosomes to induce autophagy, making ER-autophagosome adaptor activity a direct link between immune sensing and selective ER turnover [1,5]. Defects in autophagy and in the crosstalk between autophagy, gut microbiota and inflammatory responses are associated with IBD, and organelle-specific autophagy is emerging as a therapeutic target in inflammatory diseases [2,6]. Because the activity is a binding function, it is amenable to precise genetic dissection using CRISPR knockout, point mutation and knock-in models, which is why it is a tractable target for mechanistic and translational research [5,8].
• Defines the molecular tethering step of reticulophagy, a selective autophagy pathway for ER turnover.
• Provides a mechanistic link between innate immune signalling and autophagy through STING trafficking [1,5].
• Is a primordial function of the cGAS-STING pathway, conserved across evolution.
• Contributes to organelle quality control, which is dysregulated in inflammatory diseases.
• Is relevant to IBD, where autophagy, gut microbiota and inflammatory responses intersect.
• Offers a target for therapeutic modulation of selective autophagy in inflammation.
• Enables functional dissection of ER membrane contact sites with autophagosomes.
• Supports research on ER stress, ER-phagy and cellular homeostasis.
• Can be studied with CRISPR KO, point-mutation, knock-in and overexpression models [5,8].
• Informs biomarker and drug discovery efforts in autophagy-related disease [2,6].
What Happens During endoplasmic reticulum-autophagosome adaptor activity?
ER membrane recognition and adaptor recruitment
In simple terms: The adaptor protein first finds and binds the ER membrane.
The first stage of GO:0140506 is the recruitment of an adaptor protein to the ER membrane. STING is an ER-resident adaptor that facilitates innate immune signalling and is positioned at the ER under resting conditions. Upon appropriate signals, STING traffics from the ER, and this trafficking is required for autophagy induction, indicating that ER localization is a prerequisite for its adaptor function. The adaptor must therefore be able to associate with the ER membrane, either through transmembrane domains or membrane-binding motifs, before it can engage an autophagosome [1,5].
Autophagosome membrane engagement
In simple terms: The adaptor then grabs the autophagosome membrane.
In the second stage, the ER-bound adaptor engages the autophagosome membrane. STING trafficking from the ER to autophagosomes is a primordial function of the cGAS pathway, and this trafficking is necessary for autophagy induction. The adaptor activity defined by GO:0140506 is the binding event that brings the ER membrane and the autophagosome membrane together, effectively anchoring the two organelles. This step is distinct from cargo recognition because the adaptor's primary role is membrane tethering rather than substrate selection.
Membrane tethering and reticulophagy commitment
In simple terms: The two membranes are held together so the ER fragment can be degraded.
Once the adaptor has bound both membranes, the ER and autophagosome are physically tethered, committing the ER fragment to reticulophagy. This tethering is the defining output of GO:0140506 and is required for selective ER degradation. Organelle-specific autophagy, including reticulophagy, is a quality-control mechanism that is dysregulated in inflammatory diseases, underscoring the physiological importance of this tethering step.
Downstream autophagosome maturation and ER turnover
In simple terms: After tethering, the autophagosome matures and the ER is broken down.
Following tethering, the autophagosome matures and the enclosed ER material is delivered for degradation. STING trafficking to autophagosomes supports autophagy induction, and this pathway is conserved as a primordial function of the cGAS-STING axis. The interplay between autophagy, gut microbiota and inflammatory responses further indicates that efficient completion of reticulophagy has physiological consequences for inflammatory homeostasis. Defects at this stage can contribute to the accumulation of damaged ER and to inflammatory pathology.
Key Genes Involved in GO:0140506 endoplasmic reticulum-autophagosome adaptor activity
The following genes and proteins are directly or functionally linked to ER-autophagosome adaptor activity and its regulation, based on the verified literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| TMEM173 (STING) | ER-resident adaptor that facilitates innate immune signalling and traffics to autophagosomes to induce autophagy [1,5] | Core ER-autophagosome adaptor; knockout and trafficking mutants test reticulophagy and immune signalling [1,5] |
| MAP1LC3B (LC3B) | Autophagosome membrane marker and interaction partner in selective autophagy | Used to monitor autophagosome formation and colocalization with ER markers |
| SQSTM1 (p62) | Selective autophagy cargo receptor that can cooperate with adaptors | Readout for autophagic flux and cargo sequestration in inflammation models |
| ATG5 | Core autophagy machinery required for autophagosome formation | Knockout controls for autophagy dependence of ER tethering |
| ATG7 | Core autophagy machinery required for LC3 lipidation | Essential for distinguishing adaptor-dependent reticulophagy from bulk autophagy |
| BECN1 (Beclin-1) | Autophagy initiation factor | Modulates autophagosome biogenesis upstream of adaptor tethering |
| CGAS (cGAS) | Cytosolic DNA sensor upstream of STING trafficking and autophagy induction | Defines the primordial cGAS-STING autophagy axis |
| TBK1 | Kinase regulating STING trafficking and termination | Phosphorylation-dependent control of STING signalling and adaptor availability |
| AP1 complex (AP-1) | Clathrin-associated complex controlling STING termination | Regulates post-Golgi STING trafficking relevant to adaptor localization |
| NLRP3 | Inflammasome sensor linked to mitochondrial and organelle stress | Context for inflammatory consequences of defective organelle quality control |
| MAVS | Mitochondrial antiviral signalling adaptor with palmitoylation-dependent activation | Comparative adaptor biology and metabolic regulation of immune adaptors |
| CPT1A | Fatty acid oxidation enzyme that promotes MAVS palmitoylation | Links metabolic state to adaptor function and antitumor immunity |
| PDZD8 (LYVAC) | Lysosomal vacuolator involved in membrane dynamics | Related membrane-remodelling factor informing organelle tethering mechanisms |
| CALCOCO2 (NDP52) | Selective autophagy receptor | Candidate cooperating factor in ER-selective autophagy |
| OPTN (Optineurin) | Selective autophagy receptor | Candidate cooperating factor in ER-selective autophagy |
| ULK1 | Autophagy initiation kinase | Upstream regulator of autophagosome biogenesis for adaptor studies |
| WIPI2 | Autophagosome formation factor | Marker of early autophagosome biogenesis |
| VAPA/VAPB | ER membrane proteins at contact sites | Candidate ER anchors for membrane contact site studies |
How Is endoplasmic reticulum-autophagosome adaptor activity Regulated?
ER-autophagosome adaptor activity is regulated at multiple levels. STING trafficking from the ER is required for autophagy induction, and this trafficking is controlled by the cGAS-STING pathway. Termination of STING signalling is controlled by the clathrin-associated AP-1 complex, which regulates STING trafficking and thus the availability of STING at membranes. TBK1-dependent phosphorylation is also implicated in STING regulation and trafficking. More broadly, organelle-specific autophagy is regulated by core autophagy kinases and by cellular stress, and its dysregulation is linked to inflammatory diseases. Metabolic signals can also influence adaptor function, as illustrated by CPT1A induction promoting MAVS palmitoylation and activation, showing that lipid metabolism can modulate immune adaptor activity. Autophagy regulation intersects with gut microbiota and inflammatory responses, providing an environmental layer of control relevant to IBD.
endoplasmic reticulum-autophagosome adaptor activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| TMEM173 (STING) | Innate immune signalling and autophagy-related inflammation [1,5] | Knockout and trafficking-mutant knock-in cell lines [1,5] |
| SQSTM1 (p62) | IBD and autophagy-microbiota crosstalk | Knockout intestinal epithelial cells |
| NLRP3 | Inflammasome-associated inflammation | Knockout macrophages with organelle stress |
| CPT1A | Cancer immunity and metabolic regulation | Overexpression and point-mutation models |
| AP1 complex (AP-1) | STING trafficking and immune signalling disorders | Knockout for trafficking termination studies |
Inflammatory bowel disease and autophagy-microbiota crosstalk
Autophagy, gut microbiota and inflammatory responses are interconnected in IBD, and defects in selective autophagy pathways can contribute to chronic intestinal inflammation. Organelle-specific autophagy, including reticulophagy, is a quality-control mechanism whose failure is associated with inflammatory diseases. Because GO:0140506 defines the tethering step of ER degradation, its dysfunction is mechanistically positioned to contribute to ER stress and inflammation in IBD [2,6].
Innate immune signalling disorders
STING is an ER adaptor that facilitates innate immune signalling, and its trafficking to autophagosomes is a primordial function of the cGAS pathway [1,5]. Perturbations in STING trafficking, including those controlled by AP-1 and TBK1, can alter immune signalling output. Therefore, ER-autophagosome adaptor activity sits at the interface of immune activation and organelle quality control [1,5,8].
Inflammation and inflammasome-associated pathology
Mitochondria play a role in NLRP3 inflammasome activation, illustrating how organelle stress can drive inflammatory signalling. Organelle-specific autophagy is a potential therapeutic target for quality control of multiple organelles in inflammatory diseases. ER-autophagosome adaptor activity may therefore influence inflammasome-associated pathology through ER quality control [3,6].
Cancer immunity and metabolic regulation
CPT1A induction following epigenetic perturbation promotes MAVS palmitoylation and activation to potentiate antitumor immunity, demonstrating that metabolic enzymes can regulate immune adaptor function. This provides a conceptual framework in which ER-autophagosome adaptor activity could be modulated by metabolic state in cancer. Further work is needed to directly test this link for GO:0140506.
From endoplasmic reticulum-autophagosome adaptor activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is the candidate gene required for ER-autophagosome tethering? | CRISPR knockout cell line |
| Does a specific residue control adaptor binding? | Point-mutation knock-in [5,8] |
| Where does the adaptor localize during reticulophagy? | Tagged knock-in with fluorescent tag |
| Does excess adaptor drive ER turnover? | Overexpression cell model |
| Does the adaptor control inflammatory signalling? | Knockout plus cytokine/immune readouts [1,2] |
| Does metabolic state modulate adaptor function? | Overexpression and point-mutation models |
How to Study the endoplasmic reticulum-autophagosome adaptor activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Fluorescence microscopy | Colocalization of ER and autophagosome markers | Detecting adaptor-dependent tethering |
| Electron microscopy | Ultrastructure of membrane contact sites | Confirming ER-autophagosome proximity |
| LC3 flux assay | Autophagosome turnover | Testing autophagy dependence of ER degradation |
| CRISPR knockout | Loss-of-function phenotype | Causal testing of candidate adaptors |
| Point-mutation knock-in | Residue-specific function [5,8] | Mapping binding interfaces and regulatory sites [5,8] |
| Tagged knock-in | Protein localization and dynamics | Live-cell tracking of adaptor trafficking |
| Cytokine profiling | Inflammatory signalling output [1,2] | Linking adaptor activity to immune phenotypes [1,2] |
| Proteomics | Interaction partners and complexes | Identifying adaptor-associated proteins |
Imaging membrane contact sites
Fluorescence and electron microscopy can resolve ER and autophagosome membranes and detect colocalization or tethering. STING trafficking from the ER to autophagosomes can be visualized with tagged proteins, and this trafficking is required for autophagy induction. Organelle-specific autophagy studies benefit from markers of ER and autophagosomes to quantify contact sites.
Autophagic flux and cargo degradation assays
LC3 turnover and cargo-receptor degradation assays measure whether ER material is delivered to autophagosomes. STING trafficking supports autophagy induction, so flux assays can test adaptor dependence. Selective autophagy receptors such as p62 and NDP52 are useful readouts in inflammation models.
Genetic perturbation with CRISPR
CRISPR knockout, point mutation and knock-in allow causal testing of adaptor function. STING trafficking mutants have been used to dissect the autophagy arm of the cGAS-STING pathway. AP-1 and TBK1 perturbations further illustrate how trafficking regulators can be genetically dissected.
Immune and inflammatory phenotyping
Cytokine profiling and inflammasome readouts connect adaptor activity to immune outcomes. STING is an ER adaptor for innate immune signalling, so immune phenotyping is a natural companion to autophagy assays. NLRP3 and organelle stress readouts provide additional inflammatory context [3,6].
How CRISPR Can Be Used to Study GO:0140506 endoplasmic reticulum-autophagosome adaptor activity
Knockout
CRISPR knockout of candidate adaptors such as TMEM173 (STING) is used to test whether ER-autophagosome tethering and reticulophagy are lost. STING trafficking is required for autophagy induction, so knockout models can reveal the contribution of this adaptor to selective ER degradation. Knockout of core autophagy genes such as ATG5 or ATG7 provides controls for autophagy dependence.
Point Mutation
Point-mutation knock-in can dissect the residues required for ER binding, autophagosome engagement or regulatory phosphorylation. TBK1 and AP-1 control STING trafficking, and mutation of relevant sites can reveal how trafficking and adaptor function are coupled. Such models are essential when a domain is required for membrane tethering but not for other functions [5,8].
Knock-in
Tagged knock-in of adaptors enables live-cell imaging of ER-autophagosome contact sites. Because STING traffics from the ER to autophagosomes, a fluorescent knock-in can track this route and quantify tethering events. Knock-in of disease-associated variants can also test whether a variant alters adaptor activity [1,5].
Overexpression
Overexpression of an adaptor can drive excessive ER tethering and ER turnover, providing a gain-of-function test. STING trafficking supports autophagy induction, so overexpression models can amplify the phenotype for detection. Overexpression of metabolic regulators such as CPT1A can also modulate immune adaptor activity, illustrating crosstalk between metabolism and adaptor function.
How EDITGENE Supports endoplasmic reticulum-autophagosome adaptor activity Research
Researchers studying endoplasmic reticulum-autophagosome adaptor activity-related genes often need to determine whether a candidate gene is causally involved in ER tethering, autophagosome engagement or downstream inflammatory signalling. Because GO:0140506 is a binding activity, the most informative experiments are those that remove, mutate or tag the candidate adaptor and then measure membrane contact sites, autophagic flux and immune output [5,8]. EDITGENE provides the full set of CRISPR cell models required for this causal chain of evidence.
Contact EDITGENE today to design your custom CRISPR model for endoplasmic reticulum-autophagosome adaptor activity research.
Frequently Asked Questions About endoplasmic reticulum-autophagosome adaptor activity
What is GO:0140506 endoplasmic reticulum-autophagosome adaptor activity?
It is a Gene Ontology molecular_function describing the binding activity of a molecule that brings together an ER membrane and an autophagosome membrane during reticulophagy.
What does endoplasmic reticulum-autophagosome adaptor activity do?
It physically tethers the ER to the autophagosome, enabling selective ER degradation during reticulophagy.
What genes are involved in endoplasmic reticulum-autophagosome adaptor activity?
TMEM173 (STING) is the best-characterized ER adaptor, with supporting roles for autophagy genes such as ATG5, ATG7, BECN1 and MAP1LC3B [1,5].
Is STING an ER-autophagosome adaptor?
Yes, STING is an ER-resident adaptor that facilitates innate immune signalling and traffics to autophagosomes to induce autophagy [1,5].
How is endoplasmic reticulum-autophagosome adaptor activity regulated?
It is regulated by STING trafficking, TBK1-dependent phosphorylation and the clathrin-associated AP-1 complex, as well as by broader autophagy and metabolic signals [5,7,8].
What diseases are linked to endoplasmic reticulum-autophagosome adaptor activity?
Inflammatory bowel disease, innate immune signalling disorders and inflammation-associated pathology have been linked to autophagy and organelle quality control defects [2,3,6].
How do you study endoplasmic reticulum-autophagosome adaptor activity?
Common approaches include fluorescence and electron microscopy, LC3 flux assays, CRISPR knockout, point-mutation knock-in, tagged knock-in and cytokine profiling [5,6,8].
What is the difference between reticulophagy and general autophagy?
Reticulophagy is the selective autophagic degradation of ER, whereas general autophagy degrades bulk cytoplasmic material; GO:0140506 specifically describes the ER-autophagosome tethering step of reticulophagy.
Can CRISPR knockout help study endoplasmic reticulum-autophagosome adaptor activity?
Yes, CRISPR knockout of candidate adaptors such as TMEM173 (STING) can test whether ER tethering and reticulophagy are lost.
Why is endoplasmic reticulum-autophagosome adaptor activity important for inflammation research?
Because it links ER quality control to innate immune signalling and autophagy-microbiota crosstalk, processes implicated in IBD and other inflammatory diseases [2,5,6].
Conclusion
GO:0140506 endoplasmic reticulum-autophagosome adaptor activity defines the molecular tethering step that brings the ER and autophagosome membranes together during reticulophagy. STING is the best-characterized adaptor for this activity, and its trafficking from the ER to autophagosomes is a primordial function of the cGAS-STING pathway [1,5]. Because this activity connects organelle quality control to innate immunity and inflammation, it is a compelling target for mechanistic and translational research in IBD and related diseases [2,6]. CRISPR knockout, point-mutation, knock-in and overexpression models provide the causal evidence needed to move this field forward [5,8].
References
- 1. Ishikawa H et al.. 2008. STING is an endoplasmic reticulum adaptor that facilitates innate immune signalling.. Nature 455(7213):674-8 PMID: 18724357
- 2. Larabi A et al.. 2020. New insights into the interplay between autophagy, gut microbiota and inflammatory responses in IBD.. Autophagy 16(1):38-51 PMID: 31286804
- 3. Zhou R et al.. 2011. A role for mitochondria in NLRP3 inflammasome activation.. Nature 469(7329):221-5 PMID: 21124315
- 4. Yang H et al.. 2025. LYVAC/PDZD8 is a lysosomal vacuolator.. Science 389(6762):eadz0972 PMID: 40839735
- 5. Gui X et al.. 2019. Autophagy induction via STING trafficking is a primordial function of the cGAS pathway.. Nature 567(7747):262-266 PMID: 30842662
- 6. Yao RQ et al.. 2021. Organelle-specific autophagy in inflammatory diseases: a potential therapeutic target underlying the quality control of multiple organelles.. Autophagy 17(2):385-401 PMID: 32048886
- 7. Zhang G et al.. 2023. CPT1A induction following epigenetic perturbation promotes MAVS palmitoylation and activation to potentiate antitumor immunity.. Mol Cell 83(23):4370-4385.e9 PMID: 38016475
- 8. Liu Y et al.. 2022. Clathrin-associated AP-1 controls termination of STING signalling.. Nature 610(7933):761-767 PMID: 36261523
