GO:0106273 cytosol to ERGIC protein transport: Protein Trafficking Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0106273 cytosol to ERGIC protein transport describes the directed movement of proteins from the cytosol to the endoplasmic reticulum-Golgi intermediate compartment (ERGIC).
• The ERGIC is a major sorting hub on the secretory pathway, and proteins that reach it from the cytosol are typically delivered to ER membranes before entering the ER-Golgi interface.
• Key machinery includes COP-I components, the Sec13 homolog SEC13, ERGIC-53 (LMAN1), and ERp44, which together support membrane and cargo handling at the ER-ERGIC boundary.
• The pathway intersects with autophagy and immune signaling, because STING trafficking through the ERGIC is required for autophagy induction.
• Dysregulation of cytosol-to-ERGIC transport is linked to defects in protein quality control, secretion, and inflammatory cytokine release.
• CRISPR knockout, point-mutation, knock-in, and overexpression models allow causal testing of ERGIC transport genes in human cells.
Description
GO:0106273 cytosol to ERGIC protein transport is a biological process that describes the directed movement of proteins from the cytosol to the endoplasmic reticulum-Golgi intermediate compartment (ERGIC). The ERGIC is a pleiomorphic membrane system positioned between the endoplasmic reticulum (ER) and the Golgi apparatus, and it functions as a sorting station for cargo moving along the early secretory pathway. Proteins that originate in or pass through the cytosol must be delivered to this compartment in a controlled manner, and defects in this delivery step can alter membrane composition, cargo sorting, and downstream secretion. The process is experimentally tractable because ERGIC-resident proteins such as ERGIC-53 (LMAN1) and the mammalian Sec13 homolog provide markers and functional handles for transport assays. Studies of ER-to-Golgi and Golgi-to-ER trafficking have shown that COP-I coats and their regulators contribute to the membrane dynamics that connect the ER, the ERGIC, and the Golgi. More recent work has revealed that the ERGIC also serves as a platform for innate immune signaling, because STING trafficking through this compartment is required for autophagy induction. For researchers, GO:0106273 matters because it sits at the intersection of protein quality control, secretion, and stress signaling. Understanding how proteins reach the ERGIC from the cytosol helps explain how cells maintain secretory capacity, how they respond to infection, and how mutations in trafficking machinery contribute to disease.
cytosol to ERGIC protein transport At A Glance
| GO ID | GO:0106273 |
|---|---|
| GO term | cytosol to ERGIC protein transport |
| Ontology | biological_process |
| Synonym | none |
| Major function | Directed movement of proteins from the cytosol to the endoplasmic reticulum-Golgi intermediate compartment (ERGIC) |
| Compartments involved | Cytosol, ERGIC, and adjacent ER-Golgi membranes |
| Representative machinery | COP-I components, SEC13, ERGIC-53 (LMAN1), ERp44 |
| Related processes | ER-to-Golgi transport, Golgi-to-ER transport, autophagy induction via STING |
| Disease relevance | Protein quality control defects, secretory dysfunction, inflammatory signaling |
What Is GO:0106273?
In our own words, GO:0106273 cytosol to ERGIC protein transport is the directed, regulated movement of proteins from the cytosol to the endoplasmic reticulum-Golgi intermediate compartment (ERGIC). It covers the steps by which cytosolic proteins or cytosolic domains of membrane proteins are delivered to ERGIC membranes, a process that depends on membrane targeting, coat components, and cargo receptors. The term is a biological process and is distinct from general ER-to-Golgi transport, because its endpoint is specifically the ERGIC.
Why Is cytosol to ERGIC protein transport Important in Cell Biology?
GO:0106273 is important because the ERGIC is a central sorting hub for the secretory pathway, and the delivery of proteins from the cytosol to this compartment influences membrane composition, cargo selection, and downstream secretion. Perturbing this step can disrupt ER-to-Golgi transport and Golgi-to-ER recycling, which are essential for cellular homeostasis. In addition, ERGIC trafficking is now recognized as a signaling platform: STING transit through the ERGIC is required for autophagy induction, linking cytosol-to-ERGIC transport to innate immunity. Defects in ERGIC-associated quality control proteins such as ERp44 and ERGIC-53 can impair protein folding and secretion, with consequences for disease.
• Defines a specific step in the early secretory pathway that connects the cytosol to the ERGIC.
• Provides the membrane delivery route required for ER-to-Golgi transport and Golgi-to-ER recycling.
• Supports protein quality control through ERGIC-53 and ERp44 at the ER-ERGIC interface.
• Links trafficking to innate immunity because STING must transit the ERGIC to induce autophagy.
• Contributes to inflammatory cytokine secretion through trans-Golgi network-associated pathways.
• Offers druggable and CRISPR-editable nodes for studying secretory and immune disorders.
• Helps explain clinical phenotypes caused by defects in early intracellular transport of membrane proteins.
• Provides markers such as ERGIC-53 for imaging and biochemical assays of the compartment.
• Enables dissection of COP-I-dependent and COP-I-independent routes between ER, ERGIC, and Golgi.
• Creates opportunities for library screening to identify regulators of ERGIC delivery.
What Happens During cytosol to ERGIC protein transport?
Cargo recognition and membrane targeting
In simple terms: Proteins in the cytosol must first be recognized and sent toward the ERGIC membrane.
The initial step of cytosol to ERGIC protein transport involves recognition of cargo and targeting to ERGIC-adjacent membranes. Membrane proteins and secretory cargo enter the early secretory pathway at the ER, and their subsequent movement to the ERGIC depends on intrinsic sorting signals and interactions with coat and receptor proteins. The mammalian Sec13 homolog is enriched in the intermediate compartment and is essential for protein transport from the ER to the Golgi, placing it at the ERGIC step of this route.
Vesicle formation and COP-I-dependent trafficking
In simple terms: Membrane carriers bud from donor membranes and deliver cargo to the ERGIC.
Vesicle formation and membrane remodeling are required to move proteins from the cytosol-facing side of the ER into the ERGIC. COP-I components participate in transport between the Golgi and the ER, and evidence supports both COP-I-dependent and COP-I-independent routes from the Golgi complex to the ER. These pathways converge on the ERGIC, which acts as an intermediate sorting station for cargo moving in both directions.
ERGIC arrival and quality control
In simple terms: Once cargo reaches the ERGIC, quality control proteins check and retain it as needed.
At the ERGIC, cargo encounters quality control machinery including ERGIC-53 (LMAN1) and ERp44, which regulate protein folding and retention. Zinc-mediated structural and functional regulation of ERp44 and ERGIC-53 supports their roles in protein quality control at this compartment. This step ensures that only properly folded or appropriately assembled cargo proceeds further along the secretory pathway.
Signaling and autophagy coupling
In simple terms: The ERGIC is not just a traffic stop; it also helps trigger autophagy during immune signaling.
STING trafficking through the ERGIC is required for autophagy induction, revealing that cytosol-to-ERGIC transport is coupled to innate immune signaling. Autophagy induction via STING trafficking is a primordial function of the cGAS pathway, which means ERGIC transit has consequences beyond secretion. This coupling places GO:0106273 at the interface of membrane traffic and cellular stress responses.
Secretion and inflammatory output
In simple terms: Traffic through the ERGIC ultimately feeds into secretion, including release of inflammatory signals.
Trans-Golgi network-associated noncanonical autophagy depends on the V-ATPase-ATG16L1 axis and mediates IL1B secretion, connecting ERGIC-adjacent trafficking to inflammatory output. Secretion of proteins such as keratin 75 by ameloblasts in vivo illustrates how early secretory trafficking supports specialized secretory functions. Together, these findings show that cytosol-to-ERGIC transport contributes to both constitutive and regulated secretion.
Key Genes Involved in GO:0106273 cytosol to ERGIC protein transport
The following genes and proteins have been experimentally implicated in cytosol to ERGIC protein transport or in the closely related ER-ERGIC-Golgi trafficking steps that define this process.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SEC13 | Mammalian homolog of yeast Sec13p enriched in the intermediate compartment; essential for ER-to-Golgi protein transport | Core marker and functional node for ERGIC transport assays |
| LMAN1 (ERGIC-53) | ERGIC-resident cargo receptor involved in protein quality control | Marker of the ERGIC and target for folding/secretion studies |
| ERP44 | ER-resident oxidoreductase that interacts with ERGIC-53 in quality control | Zinc-regulated node for protein folding and retention |
| STING1 | Traffics through the ERGIC to induce autophagy | Links ERGIC transport to innate immunity and autophagy |
| ATG16L1 | Component of the V-ATPase-ATG16L1 axis in noncanonical autophagy | Connects ERGIC-adjacent traffic to IL1B secretion |
| IL1B | Inflammatory cytokine secreted via trans-Golgi network-associated autophagy | Readout of inflammatory secretion downstream of ERGIC traffic |
| KRT75 | Keratin secreted by ameloblasts in vivo | Model cargo for specialized secretory trafficking |
| COPI subunits | Coat components mediating Golgi-to-ER and intra-ERGIC transport | Dissect COP-I-dependent versus independent routes |
| AZIN2 | Antizyme inhibitor 2 with regulated subcellular localization | Example of intrinsic sequences and antizyme interactions controlling localization |
| Antizymes | Bind and regulate antizyme inhibitor localization | Modulators of cytosolic protein targeting |
| cGAS | Upstream sensor in the cGAS-STING pathway | Context for STING-dependent autophagy via ERGIC |
| V-ATPase | Proton pump required for noncanonical autophagy | Upstream regulator of ATG16L1-dependent secretion |
| SEC13L1 | Sec13-related trafficking factor | Candidate for ERGIC transport screening |
| LMAN1L | ERGIC-53 family member | Potential cargo receptor paralog |
| ERP44 paralogs | ER oxidoreductase family members | Quality control network at the ERGIC |
| STIM1 | ER membrane protein whose trafficking informs early secretory routes | Context for membrane protein transport studies |
| CFTR | Membrane protein whose early transport has clinical implications | Disease-relevant cargo for trafficking assays |
| GPCRs | Membrane proteins whose early transport is pharmacologically relevant | Drug target context for cytosol-to-ERGIC delivery |
How Is cytosol to ERGIC protein transport Regulated?
Cytosol to ERGIC protein transport is regulated at multiple levels. Intrinsic sequences within cargo proteins and their interactions with antizymes control subcellular localization, as shown for antizyme inhibitor 2 in mammalian cells. Zinc-mediated structural and functional regulation of ERp44 and ERGIC-53 modulates protein quality control at the ERGIC, thereby influencing which cargo proceeds. COP-I coat components and their regulators determine the balance between COP-I-dependent and COP-I-independent routes between the Golgi and the ER, which in turn affects ERGIC cargo flux. In immune contexts, STING trafficking through the ERGIC is a regulated step required for autophagy induction, linking membrane traffic to cGAS pathway signaling. Finally, the V-ATPase-ATG16L1 axis regulates trans-Golgi network-associated noncanonical autophagy and IL1B secretion, providing an additional layer of control over ERGIC-adjacent secretory output.
cytosol to ERGIC protein transport and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| LMAN1 (ERGIC-53) | Protein quality control and secretory dysfunction | Knockout and point-mutation cell models |
| ERP44 | Protein folding and zinc-regulated quality control | Knock-in of zinc-coordination mutants |
| STING1 | Innate immunity and autophagy induction via ERGIC | Knockout and tagged knock-in for trafficking assays |
| ATG16L1 | Noncanonical autophagy and IL1B secretion | Knockout and overexpression models |
| SEC13 | ER-to-Golgi transport defects | Knockout and rescue models |
Secretory and protein quality control disorders
Defects in early intracellular transport of membrane proteins have clinical and pharmacological implications, because the delivery of proteins to the ERGIC and beyond determines whether they reach their functional destinations. ERGIC-53 (LMAN1) and ERp44 participate in protein quality control, and their dysfunction can impair folding and secretion. Mutations or dysregulation in these quality control nodes may therefore contribute to secretory disorders and protein folding diseases.
Inflammation and innate immunity
STING trafficking through the ERGIC is required for autophagy induction, so perturbations in cytosol-to-ERGIC transport can alter innate immune responses. Trans-Golgi network-associated noncanonical autophagy depends on the V-ATPase-ATG16L1 axis and mediates IL1B secretion, directly linking ERGIC-adjacent trafficking to inflammatory cytokine release. These findings suggest that trafficking defects could modify inflammatory disease phenotypes.
Specialized secretory cell biology
Trafficking and secretion of keratin 75 by ameloblasts in vivo demonstrates that early secretory transport supports tissue-specific secretory functions. Disruption of ERGIC transport machinery could therefore affect specialized secretory cells, although the precise disease links remain to be defined. This area is an active target for CRISPR-based modeling.
From cytosol to ERGIC protein transport-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is SEC13 required for cytosol-to-ERGIC delivery? | SEC13 knockout with ERGIC marker imaging |
| Does ERGIC-53 quality control depend on zinc coordination? | ERP44/LMAN1 point-mutation knock-in |
| Does STING ERGIC transit control autophagy? | STING1 knockout and tagged knock-in |
| Does ATG16L1 mediate IL1B secretion? | ATG16L1 knockout and overexpression |
| Which cargo proteins use COP-I-independent routes? | COP-I subunit knockout with cargo tracking |
| Can antizyme interactions redirect cytosolic proteins? | AZIN2 overexpression and localization assays |
How to Study the cytosol to ERGIC protein transport Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Fluorescence microscopy | Co-localization of cargo with ERGIC markers | Visualizing transport steps |
| Live-cell imaging | Dynamics of cargo movement to the ERGIC | Kinetic analysis of delivery |
| In vitro transport assay | Cargo transfer between membrane fractions | Dissecting COP-I dependence |
| Co-immunoprecipitation | Interactions among ERGIC-53, ERp44, and cargo | Quality control complex mapping |
| Proteomics | Composition of ERGIC-enriched fractions | Cargo and cofactor discovery |
| CRISPR knockout screening | Genes required for ERGIC delivery | Regulator discovery |
| Autophagy flux assay | STING-dependent autophagy induction | Linking ERGIC traffic to immunity |
| Cytokine secretion assay | IL1B release via noncanonical autophagy | Inflammatory output measurement |
Imaging of ERGIC markers
Fluorescence imaging of ERGIC-resident proteins such as ERGIC-53 (LMAN1) and the Sec13 homolog allows direct visualization of cytosol-to-ERGIC delivery. Co-localization with ER and Golgi markers distinguishes the ERGIC step from upstream and downstream compartments.
Biochemical transport assays
In vitro and semi-permeabilized cell assays measure the movement of cargo from cytosol-facing membranes to the ERGIC. These assays can resolve COP-I-dependent and COP-I-independent contributions to transport.
Proteomics and interactomics
Affinity purification of ERGIC-53 and ERp44 complexes identifies quality control clients and cofactors. Proteomic profiling of ERGIC-enriched fractions can reveal cargo whose delivery depends on specific trafficking genes.
Functional genomics and screening
CRISPR library screening and RNA interference can identify genes required for cytosol-to-ERGIC transport. Reporter cargo systems coupled with autophagy or secretion readouts link trafficking to downstream phenotypes such as IL1B release.
How CRISPR Can Be Used to Study GO:0106273 cytosol to ERGIC protein transport
Knockout
CRISPR knockout of SEC13, LMAN1, or STING1 can test whether these genes are required for cytosol-to-ERGIC transport and downstream autophagy or secretion. Knockout models are particularly useful for distinguishing essential from redundant trafficking routes.
Point Mutation
Point mutations in zinc-coordinating residues of ERp44 or in cargo-binding domains of ERGIC-53 can dissect quality control mechanisms at the ERGIC. Such models preserve protein expression while altering specific functions.
Knock-in
Tagged knock-in of STING1 or ERGIC-53 enables live-cell tracking of cargo transit to the ERGIC. Knock-in reporters also allow quantitative comparison of transport efficiency across conditions.
Overexpression
Overexpression of AZIN2 or trafficking regulators can reveal dominant effects on cytosolic protein localization and ERGIC delivery. Overexpression models complement loss-of-function studies by testing sufficiency.
How EDITGENE Supports cytosol to ERGIC protein transport Research
Researchers studying cytosol to ERGIC protein transport-related genes often need to determine whether a candidate gene is causally involved in cargo delivery, quality control, or downstream secretion. EDITGENE provides CRISPR-edited cell models that allow direct testing of these hypotheses in relevant human cell backgrounds.
Contact EDITGENE today to design your custom CRISPR model for cytosol to ERGIC protein transport research.
Frequently Asked Questions About cytosol to ERGIC protein transport
What is GO:0106273 cytosol to ERGIC protein transport?
GO:0106273 is a biological process describing the directed movement of proteins from the cytosol to the endoplasmic reticulum-Golgi intermediate compartment (ERGIC).
What is the ERGIC?
The ERGIC is the endoplasmic reticulum-Golgi intermediate compartment, a sorting hub between the ER and the Golgi apparatus.
What genes are involved in cytosol to ERGIC protein transport?
Key genes include SEC13, LMAN1 (ERGIC-53), ERP44, STING1, and ATG16L1, based on published trafficking and quality control studies.
How is cytosol to ERGIC transport studied?
It is studied with fluorescence imaging of ERGIC markers, in vitro transport assays, proteomics, and CRISPR screening.
Why is the ERGIC important for autophagy?
STING trafficking through the ERGIC is required for autophagy induction, linking this transport step to innate immunity.
Does cytosol to ERGIC transport affect inflammation?
Yes, trans-Golgi network-associated noncanonical autophagy depends on the V-ATPase-ATG16L1 axis and mediates IL1B secretion.
What is the role of ERGIC-53 in protein quality control?
ERGIC-53 (LMAN1) and ERp44 participate in zinc-mediated protein quality control at the ERGIC.
Is SEC13 required for ER-to-Golgi transport?
The mammalian Sec13 homolog is enriched in the intermediate compartment and is essential for protein transport from the ER to the Golgi.
Can CRISPR be used to study ERGIC transport?
Yes, CRISPR knockout, point-mutation, knock-in, and overexpression models can test the function of ERGIC transport genes.
What diseases are linked to ERGIC transport defects?
Defects in early intracellular transport and ERGIC quality control have been linked to secretory dysfunction and inflammatory signaling.
Conclusion
GO:0106273 cytosol to ERGIC protein transport defines a specific and experimentally tractable step in the early secretory pathway. The process depends on cargo recognition, COP-I-associated membrane dynamics, and quality control factors such as ERGIC-53 and ERp44. Its importance extends beyond secretion, because STING transit through the ERGIC is required for autophagy induction and because ERGIC-adjacent trafficking mediates IL1B secretion. CRISPR-based models provide a direct way to test causality for candidate genes in this pathway. By combining knockout, point-mutation, knock-in, overexpression, and library screening approaches, researchers can map the molecular requirements for cytosol-to-ERGIC delivery and connect them to immune, inflammatory, and secretory phenotypes.
References
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- 2. López-Contreras AJ et al.. 2009. Subcellular localization of antizyme inhibitor 2 in mammalian cells: Influence of intrinsic sequences and interaction with antizymes.. J Cell Biochem 107(4):732-40 PMID: 19449338
- 3. Long J et al.. 2026. Trans-Golgi network-associated noncanonical autophagy depends on the V-ATPase-ATG16L1 axis and mediates IL1B secretion.. Autophagy 22(4):691-708 PMID: 41361996
- 4. Tang BL et al.. 1997. The mammalian homolog of yeast Sec13p is enriched in the intermediate compartment and is essential for protein transport from the endoplasmic reticulum to the Golgi apparatus.. Mol Cell Biol 17(1):256-66 PMID: 8972206
- 5. Schülein R. 2004. The early stages of the intracellular transport of membrane proteins: clinical and pharmacological implications.. Rev Physiol Biochem Pharmacol 151:45-91 PMID: 15103508
- 6. Girod A et al.. 1999. Evidence for a COP-I-independent transport route from the Golgi complex to the endoplasmic reticulum.. Nat Cell Biol 1(7):423-30 PMID: 10559986
- 7. Yang X et al.. 2019. Trafficking and secretion of keratin 75 by ameloblasts in vivo.. J Biol Chem 294(48):18475-18487 PMID: 31628189
- 8. Watanabe S et al.. 2026. Zinc-mediated structural and functional regulation of ERp44 and ERGIC-53 in protein quality control.. J Biochem 180(2):101-110 PMID: 42083771
