The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.

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this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.

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Research report: Human COPG2 (UniProt Q9UBF2) — functional annotation

0) Identity verification (required)

The UniProt accession provided (Q9UBF2) corresponds to human COPG2, described as coatomer subunit gamma-2 (also called γ2-COP) and belongs to the COPG family, consistent with a COPI/coatomer-related protein and the ARM/HEAT-like solenoid architecture typical for adaptor/coat proteins. Literature retrieved here consistently treats COPG2 as the γ-COP paralog of COPG1, i.e., γ2-COP vs γ1-COP (goyal2019paralogspecificrole pages 28-31, zhao2021roleofcopi pages 80-86). One preprint claims COPG2 is “not part of the COPI coatomer” under its biochemical/phenotypic framing, but still explicitly treats it as a γ-COP paralogue (panteloglou2025thecopicoatomer pages 5-8). No evidence in the retrieved corpus indicates we are dealing with a different organism or a different gene product than the intended human COPG2.

1) Key concepts and definitions (current understanding)

1.1 COPI/coatomer and vesicular trafficking

COPI (coat protein complex I) is a cytosolic coat complex that assembles on Golgi/ERGIC membranes to drive retrograde trafficking from the Golgi to the ER and also supports intra-Golgi transport. A mechanistic overview in an authoritative review of the ER–Golgi interface describes ARF1 activation by ARF-GEFs such as GBF1 and subsequent recruitment of the COPI coatomer to membranes at the cis-Golgi/ERGIC (maeda2025disease‐associatedfactorsat pages 4-5, maeda2025disease‐associatedfactorsat pages 5-6). This provides the pathway context in which a γ-COP family subunit (including paralogs) functions.

1.2 COPG1 versus COPG2 (paralog concept)

Multiple sources summarize that mammals have two γ-COP paralogs, COPG1 (γ1-COP) and COPG2 (γ2-COP), with ~80% overall amino-acid identity and domain-level identities in the trunk (~81%) and appendage (~75%) regions (mouse values reported in a detailed neuronal differentiation thesis synthesis) (goyal2019paralogspecificrole pages 28-31). The same source notes a ~30 amino-acid N-terminal extension in the γ2 paralog (goyal2019paralogspecificrole pages 28-31). These data support the concept that COPG2 is structurally close to canonical γ-COP but may enable paralog-specific interactions or localization.

2) Biological function, pathways, and subcellular localization

2.1 Primary function (most defensible functional statement)

Across the retrieved evidence, the most supportable “primary function” statement is:

• COPG2 encodes γ2-COP, a paralog of γ1-COP involved in COPI/coatomer biology and Golgi-associated membrane trafficking, with partial functional redundancy with COPG1 but measurable paralog-specific roles in some contexts (notably neuronal differentiation). (zhao2021roleofcopi pages 80-86, goyal2019paralogspecificrole pages 65-69)

A key nuance is that some works treat γ2-COP as an alternative coatomer component and others treat it as a paralog that may be low-abundance or context-dependent in assembled coats.

2.2 Recruitment and pathway context (ARF1/GBF1)

A mechanistic description of COPI assembly in neuronal-trafficking context states that coat assembly begins with Arf1 binding to Golgi membranes, with GBF1 as the Arf1 GEF, and that Arf1 activation exposes an N-terminal amphipathic helix to anchor in the membrane, recruiting coatomer as an intact unit (goyal2019paralogspecificrole pages 28-31). In a neuronal paralog study, Brefeldin A (BFA) is described as an inhibitor of GBF1, thereby blocking Arf activation prior to coatomer recruitment to Golgi membranes—supporting the centrality of GBF1→ARF→coatomer recruitment for COPI biology (zhao2021roleofcopi pages 80-86).

2.3 Subcellular localization (Golgi compartment bias)

A detailed neuronal differentiation thesis (summarizing prior localization work) reports differential Golgi enrichment: γ1-COP is enriched at the cis-Golgi, whereas γ2-COP (COPG2) is enriched at the trans-Golgi (goyal2019paralogspecificrole pages 65-69). While this is not a direct localization experiment in the excerpted text, it is the most specific localization distinction recovered here.

3) Recent developments and latest research (prioritizing 2023–2024)

The 2023–2024 literature retrieved that most directly addresses COPG2 focuses less on COPI vesicle biochemistry per se and more on locus regulation / imprinting and neurodevelopment, reflecting where “new” COPG2-specific insights currently appear.

3.1 COPG2 in the MEST/COPG2 imprinted domain and isoform regulation (2024)

A 2024 dissertation-level work on transcript regulation at the Mest/MEST locus reports that, in mouse CNS, an alternative polyadenylation event generates an extended MestXL transcript that extends ~40 kb into the Copg2 locus and is proposed to suppress paternal Copg2 expression, generating maternal-biased Copg2 expression; truncating MestXL via polyadenylation signal insertion restores biallelic Copg2 expression (ashworth2024alternativepolyadenylationat pages 24-29). The same source notes that in humans at 7q32.2, the imprinting status of COPG2 has been debated, ranging from paternal to biallelic expression, and highlights a human antisense transcript COPG2IT1 as potentially analogous to mouse antisense/transcriptional interference architectures (ashworth2024alternativepolyadenylationat pages 24-29).

This line of evidence is important for functional annotation because it suggests that cell-type-specific regulation (particularly neuronal lineages) may be a key dimension of COPG2 biology, potentially impacting trafficking capacity in neurons without requiring changes in protein catalytic function (ashworth2024alternativepolyadenylationat pages 24-29).

4) Experimental evidence and quantitative data (selected highlights)

4.1 Paralog-specific roles in neuronal differentiation (quantitative and mechanistic)

A neuronal differentiation study (preprint/thesis-derived) reports:
- γ1-COP depletion disrupts neurite extension, while γ2-COP removal does not measurably affect neurite outgrowth in the same paradigm, and γ2-COP expressed from the Copg1 locus only partially rescues γ1-COP loss, supporting paralog specialization (zhao2021roleofcopi pages 80-86).
- Proximity labeling / interactome profiling using cutoffs p < 0.01 and |log2 fold change| > 2 identified 21 proteins enriched with γ1-COP vs 17 with γ2-COP in undifferentiated cells; in differentiated neurons 8 γ1-specific vs 7 γ2-specific proteins were reported (zhao2021roleofcopi pages 86-89). These quantitative differences support the concept that paralogs differ in interaction neighborhoods.
- The same work suggests γ2/z2-containing coatomer complexes may be rare; prior quantification summarized there suggests γ2/z2 coatomer is absent or at most ~5% of total coatomer (zhao2021roleofcopi pages 86-89).

A 2019 thesis analysis similarly concludes that COPG1 and COPG2 are only partially redundant and likely specialized, and reports neurite-length analysis significance with n = 12 images and *p < 0.0001 in the referenced analyses (goyal2019paralogspecificrole pages 65-69).

4.2 Hepatocyte trafficking phenotypes (quantitative; 2025 preprint but informative)

In a genome-wide RNAi screen for genes limiting hepatocyte HDL uptake, canonical COPI genes (e.g., COPA/COPB1/COPB2/ARCN1/COPG1/COPZ1) reduced HDL uptake strongly when silenced, while COPG2 knockdown did not alter HDL uptake; pooled siRNA reduced target mRNA by 67–90%. Indispensable subunit silencing reduced HDL uptake by ≥75% (protein-labeled) and 79% (lipid-labeled), while comparison of indispensable vs dispensable/paralogous genes was p < 0.001 (panteloglou2025thecopicoatomer pages 5-8). Notably, COPG2 knockdown increased apoA-I secretion by 33% (panteloglou2025thecopicoatomer pages 8-11).

This supports a functional interpretation where COPG2 can be non-essential for some COPI-dependent phenotypes in hepatocytes (and may even modulate secretory outputs), highlighting context dependence.

4.3 Innate immune signaling link (COPI broadly; COPG2 perturbation measured)

A high-impact study showed that deficiency in COPI-mediated trafficking can cause aberrant activation of cGAS/STING signaling (steiner2022deficiencyincoatomer pages 10-11). Within their experimental framework, COPG2 was among targeted genes in THP-1 cells with qRT-PCR and baseline signaling measurements (small n in excerpt: typically n = 2 for qRT-PCR/immunoblot summaries) (steiner2022deficiencyincoatomer pages 10-11). While this does not establish COPG2 as the driver subunit (the paper emphasizes other COPI subunits more strongly in the retrieved excerpt), it provides mechanistic context that COPI perturbation can engage innate immune pathways.

A schematic depiction of this COPI→STING mechanism is shown in Steiner et al. Figure 5a (steiner2022deficiencyincoatomer media b75a2254, steiner2022deficiencyincoatomer media e6e49be1).

4.4 Protein proximity/colocalization evidence (BioID + STED)

A proximity-labeling interactome study in LNCaP prostate cancer cells used BioID (BirA) and identified 64 potential ANO7-interacting proteins after filtering; COPG2 was among four proteins followed up by dual fluorescent immunostaining and STED microscopy* and reported to colocalize with ANO7 (kaikkonen2020theinteractomeof pages 1-2). BioID indicates proximity (within ~10 nm) rather than direct binding, but it supports COPG2 presence in a vesicle-associated neighborhood in this cellular setting.

5) Current applications and real-world implementations

COPG2 is not (in the retrieved corpus) a common direct therapeutic target; instead it appears in several implementation contexts:

1. Functional genomics screens and trafficking phenotyping: The hepatocyte HDL-uptake RNAi screen explicitly tested COPG2 among coatomer-related genes to assess effects on HDL handling and apoA-I secretion, an example of applying COPG2 perturbation as part of systems-level trafficking biology (panteloglou2025thecopicoatomer pages 5-8, panteloglou2025thecopicoatomer pages 8-11).
2. Cell biology of differentiation: Neuronal differentiation experiments (KO/rescue + proximity labeling) operationalize COPG2 as a variable that can be manipulated to dissect paralog specialization in secretory pathway demands of neurons (zhao2021roleofcopi pages 80-86, zhao2021roleofcopi pages 86-89).
3. Disease-target knowledgebases: OpenTargets lists associations between COPG2 and several diseases (e.g., Alzheimer disease, Parkinson disease, multiple sclerosis, lysosomal storage disease, skeletal abnormalities) at modest scores, reflecting aggregation of heterogeneous evidence rather than definitive causality (OpenTargets Search: -COPG2).

6) Expert opinions and interpretive synthesis (authoritative analysis)

The most consistent expert-level synthesis supported by the retrieved evidence is:

• COPG2 should be annotated as a COPI/coatomer-related γ-COP paralog whose roles are context dependent and may be more specialized than “generic COPI vesicle formation.” Neuronal systems, in particular, exhibit paralog-specific requirements (γ1 critical for neurite outgrowth; γ2 less so) and distinct interaction partners, supporting a model where the γ paralogs contribute to spatial (cis vs trans Golgi) and/or cargo-selection micro-specialization even if in vitro vesicle reconstitution can appear similar (zhao2021roleofcopi pages 80-86, goyal2019paralogspecificrole pages 65-69, zhao2021roleofcopi pages 86-89).

• Gene regulation at the MEST/COPG2 locus (including imprinting and antisense transcription) may be a major determinant of when and where COPG2 contributes to cellular physiology, particularly in neuronal lineages; in humans, the imprinting status is not settled in the retrieved 2024 synthesis, suggesting caution in over-committing to a single imprinting model for human COPG2 (ashworth2024alternativepolyadenylationat pages 24-29).

• Conflicting membership statements: A review of ER–Golgi disease factors lists COPG2 among COPI coatomer subunits (maeda2025disease‐associatedfactorsat pages 4-5), while a functional RNAi preprint explicitly states COPG2 is “not part of the COPI coatomer” in their framework (panteloglou2025thecopicoatomer pages 5-8). The most conservative resolution is to annotate COPG2 as a γ-COP paralog intimately linked to COPI biology, with the possibility that its incorporation into functional coatomer is cell-type-, condition-, or abundance-dependent (zhao2021roleofcopi pages 86-89, panteloglou2025thecopicoatomer pages 5-8).

7) Statistics/data summary (selected)

Key quantitative observations extracted from the retrieved corpus:
- γ1/γ2 paralog similarity: ~80% overall identity; trunk ~81%, appendage ~75%; γ2 has ~30 aa N-terminal extension (goyal2019paralogspecificrole pages 28-31).
- Neuronal paralog interactomes: 21 vs 17 proteins enriched (undifferentiated); 8 vs 7 (neurons) under p < 0.01 and FC ±2 criteria (zhao2021roleofcopi pages 86-89).
- Estimated abundance: γ2/z2 coatomer ≤ ~5% of total coatomer (zhao2021roleofcopi pages 86-89).
- Hepatocyte screen: pooled siRNA knockdown reduced target mRNA 67–90%; essential COPI subunits reduced HDL uptake ≥75%/79% depending on tracer; COPG2 knockdown did not reduce uptake; apoA-I secretion increased 33% with COPG2 knockdown; indispensable vs dispensable comparison p < 0.001 (panteloglou2025thecopicoatomer pages 5-8, panteloglou2025thecopicoatomer pages 8-11).
- Locus regulation: MestXL extends ~40 kb into Copg2 (mouse) (ashworth2024alternativepolyadenylationat pages 24-29).

8) Key evidence table

Table: This table compiles the most relevant evidence for human COPG2, covering identity, trafficking role, localization, neuronal phenotypes, imprinting, disease links, and interactome data. It is useful as a source-tracked overview of what is directly supported versus what remains inferred or debated.

9) URLs and publication dates (key sources used here)

• Steiner et al. Nature Communications (Apr 2022): “Deficiency in coatomer complex I causes aberrant activation of STING signalling.” https://doi.org/10.1038/s41467-022-29946-6 (steiner2022deficiencyincoatomer pages 10-11)
• Ashworth (Jan 2024) dissertation: “Alternative polyadenylation at Mest.” https://doi.org/10.14288/1.0447285 (ashworth2024alternativepolyadenylationat pages 24-29)
• Kaikkonen et al. Cancer Biomarkers (Apr 2020): “The interactome of the prostate-specific protein Anoctamin 7.” https://doi.org/10.3233/cbm-190993 (kaikkonen2020theinteractomeof pages 1-2)
• Zhao (Jan 2021) preprint/thesis: “Role of COPI paralogous proteins during pluripotent cells differentiation into neurons.” https://doi.org/10.11588/heidok.00030331 (zhao2021roleofcopi pages 80-86, zhao2021roleofcopi pages 86-89)
• Maeda et al. Traffic (Jan 2025): “Disease-Associated Factors at the Endoplasmic Reticulum–Golgi Interface.” https://doi.org/10.1111/tra.70001 (maeda2025disease‐associatedfactorsat pages 4-5)
• Panteloglou et al. medRxiv (Aug 2025): “The COPI coatomer regulates several steps of HDL metabolism.” https://doi.org/10.1101/2025.08.21.25332476 (panteloglou2025thecopicoatomer pages 5-8, panteloglou2025thecopicoatomer pages 8-11)
• OpenTargets association summary for COPG2 (accessed via tool; date not embedded in export): https://platform.opentargets.org/ (OpenTargets Search: -COPG2)

10) Limitations of the current evidence base

COPG2 itself has relatively limited direct human biochemical characterization in the retrieved set, and several key mechanistic claims are derived from (i) paralog studies in mouse/rat or P19 cells, (ii) systems screens, or (iii) dissertations/preprints. Where the literature conflicts (e.g., COPG2 incorporation into COPI), the report uses conservative language and explicitly cites the disagreement (maeda2025disease‐associatedfactorsat pages 4-5, panteloglou2025thecopicoatomer pages 5-8).

References

1. (goyal2019paralogspecificrole pages 28-31): Manu Jain Goyal. Paralog specific role of copi pathway in p19 neuronal differentiation. Text, Jan 2019. URL: https://doi.org/10.11588/heidok.00026911, doi:10.11588/heidok.00026911. This article has 1 citations and is from a peer-reviewed journal.

2. (zhao2021roleofcopi pages 80-86): Xiyan Zhao. Role of copi paralogous proteins during pluripotent cells differentiation into neurons. ArXiv, Jan 2021. URL: https://doi.org/10.11588/heidok.00030331, doi:10.11588/heidok.00030331. This article has 0 citations.

3. (panteloglou2025thecopicoatomer pages 5-8): Grigorios Panteloglou, Paolo Zanoni, Christopher S. Law, Brian Woods, Alaa Othman, Mustafa Yalcinkaya, Simon F. Norrelykke, Andrzej J. Rzepiela, Szymon Stoma, Michael Stebler, Anja Kerksiek, Michele Visentin, Marieke Smit, Sofia Kakava, Anton Potapenko, Eveline Schlumpf, Silvija Radosavljevic, Marta Futema, Nawar Dalila, Anne Tybjaerg-Hansen, Steve E. Humphries, Jan Albert Kuivenhoven, Bart van de Sluis, Dieter Lütjohann, Roger Meier, Jérôme Robert, Janet Chou, Raif S. Geha, Anthony K. Shum, Lucia Rohrer, and Arnold von Eckardstein. The copi coatomer regulates several steps of hdl metabolism. MedRxiv, Aug 2025. URL: https://doi.org/10.1101/2025.08.21.25332476, doi:10.1101/2025.08.21.25332476. This article has 0 citations.

4. (maeda2025disease‐associatedfactorsat pages 4-5): Miharu Maeda, Masashi Arakawa, and Kota Saito. Disease‐associated factors at the endoplasmic reticulum–golgi interface. Traffic (Copenhagen, Denmark), Jan 2025. URL: https://doi.org/10.1111/tra.70001, doi:10.1111/tra.70001. This article has 2 citations.

5. (maeda2025disease‐associatedfactorsat pages 5-6): Miharu Maeda, Masashi Arakawa, and Kota Saito. Disease‐associated factors at the endoplasmic reticulum–golgi interface. Traffic (Copenhagen, Denmark), Jan 2025. URL: https://doi.org/10.1111/tra.70001, doi:10.1111/tra.70001. This article has 2 citations.

6. (goyal2019paralogspecificrole pages 65-69): Manu Jain Goyal. Paralog specific role of copi pathway in p19 neuronal differentiation. Text, Jan 2019. URL: https://doi.org/10.11588/heidok.00026911, doi:10.11588/heidok.00026911. This article has 1 citations and is from a peer-reviewed journal.

7. (ashworth2024alternativepolyadenylationat pages 24-29): Nolan Ashworth. Alternative polyadenylation at mest. Text, Jan 2024. URL: https://doi.org/10.14288/1.0447285, doi:10.14288/1.0447285. This article has 0 citations and is from a peer-reviewed journal.

8. (zhao2021roleofcopi pages 86-89): Xiyan Zhao. Role of copi paralogous proteins during pluripotent cells differentiation into neurons. ArXiv, Jan 2021. URL: https://doi.org/10.11588/heidok.00030331, doi:10.11588/heidok.00030331. This article has 0 citations.

9. (panteloglou2025thecopicoatomer pages 8-11): Grigorios Panteloglou, Paolo Zanoni, Christopher S. Law, Brian Woods, Alaa Othman, Mustafa Yalcinkaya, Simon F. Norrelykke, Andrzej J. Rzepiela, Szymon Stoma, Michael Stebler, Anja Kerksiek, Michele Visentin, Marieke Smit, Sofia Kakava, Anton Potapenko, Eveline Schlumpf, Silvija Radosavljevic, Marta Futema, Nawar Dalila, Anne Tybjaerg-Hansen, Steve E. Humphries, Jan Albert Kuivenhoven, Bart van de Sluis, Dieter Lütjohann, Roger Meier, Jérôme Robert, Janet Chou, Raif S. Geha, Anthony K. Shum, Lucia Rohrer, and Arnold von Eckardstein. The copi coatomer regulates several steps of hdl metabolism. MedRxiv, Aug 2025. URL: https://doi.org/10.1101/2025.08.21.25332476, doi:10.1101/2025.08.21.25332476. This article has 0 citations.

10. (steiner2022deficiencyincoatomer pages 10-11): Annemarie Steiner, Katja Hrovat-Schaale, Ignazia Prigione, Chien-Hsiung Yu, Pawat Laohamonthonkul, Cassandra R. Harapas, Ronnie Ren Jie Low, Dominic De Nardo, Laura F. Dagley, Michael J. Mlodzianoski, Kelly L. Rogers, Thomas Zillinger, Gunther Hartmann, Michael P. Gantier, Marco Gattorno, Matthias Geyer, Stefano Volpi, Sophia Davidson, and Seth L. Masters. Deficiency in coatomer complex i causes aberrant activation of sting signalling. Nature Communications, Apr 2022. URL: https://doi.org/10.1038/s41467-022-29946-6, doi:10.1038/s41467-022-29946-6. This article has 99 citations and is from a highest quality peer-reviewed journal.

11. (steiner2022deficiencyincoatomer media b75a2254): Annemarie Steiner, Katja Hrovat-Schaale, Ignazia Prigione, Chien-Hsiung Yu, Pawat Laohamonthonkul, Cassandra R. Harapas, Ronnie Ren Jie Low, Dominic De Nardo, Laura F. Dagley, Michael J. Mlodzianoski, Kelly L. Rogers, Thomas Zillinger, Gunther Hartmann, Michael P. Gantier, Marco Gattorno, Matthias Geyer, Stefano Volpi, Sophia Davidson, and Seth L. Masters. Deficiency in coatomer complex i causes aberrant activation of sting signalling. Nature Communications, Apr 2022. URL: https://doi.org/10.1038/s41467-022-29946-6, doi:10.1038/s41467-022-29946-6. This article has 99 citations and is from a highest quality peer-reviewed journal.

12. (steiner2022deficiencyincoatomer media e6e49be1): Annemarie Steiner, Katja Hrovat-Schaale, Ignazia Prigione, Chien-Hsiung Yu, Pawat Laohamonthonkul, Cassandra R. Harapas, Ronnie Ren Jie Low, Dominic De Nardo, Laura F. Dagley, Michael J. Mlodzianoski, Kelly L. Rogers, Thomas Zillinger, Gunther Hartmann, Michael P. Gantier, Marco Gattorno, Matthias Geyer, Stefano Volpi, Sophia Davidson, and Seth L. Masters. Deficiency in coatomer complex i causes aberrant activation of sting signalling. Nature Communications, Apr 2022. URL: https://doi.org/10.1038/s41467-022-29946-6, doi:10.1038/s41467-022-29946-6. This article has 99 citations and is from a highest quality peer-reviewed journal.

13. (kaikkonen2020theinteractomeof pages 1-2): Elina Kaikkonen, Aliisa Takala, Juha-Pekka Pursiheimo, Gudrun Wahlström, and Johanna Schleutker. The interactome of the prostate-specific protein anoctamin 7. Cancer Biomarkers, 28:91-100, Apr 2020. URL: https://doi.org/10.3233/cbm-190993, doi:10.3233/cbm-190993. This article has 20 citations and is from a peer-reviewed journal.

14. (OpenTargets Search: -COPG2): Open Targets Query (-COPG2, 8 results). Buniello, A. et al. (2025). Open Targets Platform: facilitating therapeutic hypotheses building in drug discovery. Nucleic Acids Research.

15. (panteloglou2025thecopicoatomer pages 14-17): Grigorios Panteloglou, Paolo Zanoni, Christopher S. Law, Brian Woods, Alaa Othman, Mustafa Yalcinkaya, Simon F. Norrelykke, Andrzej J. Rzepiela, Szymon Stoma, Michael Stebler, Anja Kerksiek, Michele Visentin, Marieke Smit, Sofia Kakava, Anton Potapenko, Eveline Schlumpf, Silvija Radosavljevic, Marta Futema, Nawar Dalila, Anne Tybjaerg-Hansen, Steve E. Humphries, Jan Albert Kuivenhoven, Bart van de Sluis, Dieter Lütjohann, Roger Meier, Jérôme Robert, Janet Chou, Raif S. Geha, Anthony K. Shum, Lucia Rohrer, and Arnold von Eckardstein. The copi coatomer regulates several steps of hdl metabolism. MedRxiv, Aug 2025. URL: https://doi.org/10.1101/2025.08.21.25332476, doi:10.1101/2025.08.21.25332476. This article has 0 citations.

16. (panteloglou2025thecopicoatomer pages 28-31): Grigorios Panteloglou, Paolo Zanoni, Christopher S. Law, Brian Woods, Alaa Othman, Mustafa Yalcinkaya, Simon F. Norrelykke, Andrzej J. Rzepiela, Szymon Stoma, Michael Stebler, Anja Kerksiek, Michele Visentin, Marieke Smit, Sofia Kakava, Anton Potapenko, Eveline Schlumpf, Silvija Radosavljevic, Marta Futema, Nawar Dalila, Anne Tybjaerg-Hansen, Steve E. Humphries, Jan Albert Kuivenhoven, Bart van de Sluis, Dieter Lütjohann, Roger Meier, Jérôme Robert, Janet Chou, Raif S. Geha, Anthony K. Shum, Lucia Rohrer, and Arnold von Eckardstein. The copi coatomer regulates several steps of hdl metabolism. MedRxiv, Aug 2025. URL: https://doi.org/10.1101/2025.08.21.25332476, doi:10.1101/2025.08.21.25332476. This article has 0 citations.

Artifacts

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Citations

1. panteloglou2025thecopicoatomer pages 5-8
2. goyal2019paralogspecificrole pages 28-31
3. zhao2021roleofcopi pages 80-86
4. goyal2019paralogspecificrole pages 65-69
5. ashworth2024alternativepolyadenylationat pages 24-29
6. zhao2021roleofcopi pages 86-89
7. panteloglou2025thecopicoatomer pages 8-11
8. steiner2022deficiencyincoatomer pages 10-11
9. kaikkonen2020theinteractomeof pages 1-2
10. panteloglou2025thecopicoatomer pages 14-17
11. panteloglou2025thecopicoatomer pages 28-31
12. https://doi.org/10.1038/s41467-022-29946-6
13. https://doi.org/10.14288/1.0447285
14. https://doi.org/10.3233/cbm-190993
15. https://doi.org/10.11588/heidok.00030331
16. https://doi.org/10.1111/tra.70001
17. https://doi.org/10.1101/2025.08.21.25332476
18. https://platform.opentargets.org/
19. https://doi.org/10.11588/heidok.00026911,
20. https://doi.org/10.11588/heidok.00030331,
21. https://doi.org/10.1101/2025.08.21.25332476,
22. https://doi.org/10.1111/tra.70001,
23. https://doi.org/10.14288/1.0447285,
24. https://doi.org/10.1038/s41467-022-29946-6,
25. https://doi.org/10.3233/cbm-190993,

Functional Annotation of the Human COPG2 Gene (Coatomer Subunit Gamma-2)

Overview and Gene Context

COPG2 encodes the γ2-COP protein, one of the gamma subunits of the COPI (coat protein complex I) vesicle coat in human cells (pmc.ncbi.nlm.nih.gov). COPI is a heptameric protein complex (coatomer) composed of seven subunits (α-, β-, β′-, γ-, δ-, ε-, ζ-COP) that assemble on Golgi membranes to form vesicle coats (pmc.ncbi.nlm.nih.gov) (pubmed.ncbi.nlm.nih.gov). In mammals, two isoforms exist for the γ subunit: γ1-COP (encoded by COPG1) and γ2-COP (encoded by COPG2), which share ~80% sequence identity (pmc.ncbi.nlm.nih.gov). These arose from gene duplication and are highly conserved across eukaryotes (yeast has a single γ-COP homolog, Sec21p, essential for viability). COPG2 was initially identified as “gamma2-COP” on human chromosome 7q32 in an imprinted gene cluster (pmc.ncbi.nlm.nih.gov). Notably, COPG2 lies near the imprinted MEST/Peg1 gene, and early studies suggested allele-specific expression; however, expression of COPG2 is generally biallelic with some tissue-specific regulatory effects from the MEST locus (pubmed.ncbi.nlm.nih.gov) (pubmed.ncbi.nlm.nih.gov). This places COPG2 in a unique genomic context, though its primary role is structural in vesicle trafficking rather than epigenetic regulation.

Molecular Function of γ2-COP Protein

The γ2-COP protein is a structural component of the COPI coat complex and is not an enzyme or transporter. Its primary function is to help form the lattice of the COPI coat on budding vesicles and to organize interactions with other coatomer subunits, cargo proteins, and regulatory factors (pmc.ncbi.nlm.nih.gov) (pubmed.ncbi.nlm.nih.gov). COPI-coated vesicles mediate retrograde transport from the Golgi back to the endoplasmic reticulum (ER) as well as intra-Golgi transport between Golgi cisternae (pubmed.ncbi.nlm.nih.gov). During vesicle formation, the small GTPase ARF1 in its GTP-bound form recruits coatomer to the Golgi membrane (pmc.ncbi.nlm.nih.gov). The coatomer then binds to sorting signals on the cytosolic tails of cargo proteins – notably, dilysine motifs (KKXX or KXKXX at the C-terminus of membrane proteins) which serve as ER retrieval signals (pubmed.ncbi.nlm.nih.gov). These interactions ensure that ER-resident proteins (e.g. those captured by KDEL receptors) and other cargo are selectively packaged into the budding COPI vesicle for transport back to the ER (pubmed.ncbi.nlm.nih.gov). While binding of the dilysine motifs is mediated largely by the α- and β′-COP subunits of coatomer (pubmed.ncbi.nlm.nih.gov), the γ-COP subunits (γ1/γ2) contribute to the overall coat architecture and recruitment of regulatory factors.

Importantly, the γ2-COP protein contains a C-terminal appendage (ear) domain structurally similar to the appendages of clathrin adaptins (pubmed.ncbi.nlm.nih.gov). The crystal structure of the γ-COP appendage revealed a platform subdomain that provides a protein–protein interaction site (pubmed.ncbi.nlm.nih.gov). In yeast, this site on γ-COP binds the ARF GTPase-activating protein Glo3p, and in mammals γ-COP similarly binds ARFGAP2 (a Glo3p ortholog) (pubmed.ncbi.nlm.nih.gov). This interaction links the coatomer to ARF regulatory machinery: ARFGAP proteins trigger ARF1 GTP hydrolysis, promoting uncoating once the vesicle buds. Thus, γ2-COP is thought to help time the vesicle uncoating and perhaps also contribute to cargo selection through ARFGAP-dependent mechanisms (pubmed.ncbi.nlm.nih.gov). Additionally, mutational analysis in yeast (Sec21p) suggests the γ-COP appendage may have a second interface that contacts the coatomer’s α/β′/ε subcomplex, helping bridge the two halves of the complex (pubmed.ncbi.nlm.nih.gov). Overall, γ2-COP serves as a scaffolding molecule in the COPI coat, coordinating coat assembly and disassembly by binding other coat subunits, ARF1, ARF-GAPs, and possibly accessory proteins. It does not catalyze a chemical reaction nor transport a substrate in the classical sense; rather, its “substrate” is the nascent vesicle membrane/cargo complex, which it helps to deform and pinch off in concert with the rest of coatomer.

Biological Processes and Pathways

As part of the COPI coat, COPG2/γ2-COP is critically involved in the early secretory pathway – especially retrograde Golgi–ER transport. COPI-coated vesicles retrieve escaped ER proteins and recycling membrane proteins from the Golgi, maintaining protein localization and organelle homeostasis (pubmed.ncbi.nlm.nih.gov). For example, membrane proteins bearing a KKXX retrieval signal (such as the KDEL receptor loaded with ER chaperones) are captured by coatomer and sent back to the ER (pubmed.ncbi.nlm.nih.gov). COPI vesicles also mediate intra-Golgi traffic, carrying enzymes and other cargo between Golgi cisternae (pubmed.ncbi.nlm.nih.gov). This is crucial for the Golgi’s function as a processing and sorting station. Indeed, one model of Golgi transport (the cisternal maturation model) assigns COPI vesicles the role of recycling Golgi-resident enzymes backwards within the stack, thereby preserving the polarized distribution of enzymes (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). In any case, COPI (and thus γ2-COP) is essential for retrograde transport and for the fidelity of protein sorting in the secretory pathway.

In addition to transport, COPI coat function contributes to Golgi structural maintenance and dynamics. Experimental disruption of coatomer subunits leads to Golgi disorganization. Notably, knockout of the γ2-COP gene in cells (or its paralog γ1-COP) causes fragmentation of the Golgi: electron microscopy of cells lacking γ2-COP showed an increased number of smaller Golgi stacks relative to wild-type (pmc.ncbi.nlm.nih.gov), and similarly shortened Golgi cisternae length (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). In γ1-COP–deficient cells, an abnormal accumulation of vesicles at Golgi remnants was observed, indicating pronounced Golgi fragmentation when the coat is compromised (pmc.ncbi.nlm.nih.gov). These phenotypes underscore that a functional COPI coat (with either γ1 or γ2) is required to maintain normal Golgi architecture (pmc.ncbi.nlm.nih.gov), likely by continuously retrieving membrane and proteins to counterbalance the anterograde flow. Consistent with these findings, coatomer also influences processing and turnover of certain membrane proteins; for example, coatomer-mediated retrieval has been implicated in the proper recycling of LDL receptors and in processing of the amyloid precursor protein (www.proteinatlas.org) (pmc.ncbi.nlm.nih.gov). Thus, COPG2’s role in COPI impacts not only vesicle trafficking but also downstream cellular processes such as lipid uptake (via LDLR) and protein cleavage pathways, through its effect on protein localization.

At the cellular pathway level, COPG2/γ2-COP functions in concert with ARF1 and ARF-GAP in the vesicle budding/uncoating cycle. ARF1-GTP recruits coatomer to initiate a bud, and after vesicle scission, ARF1 is inactivated by ARFGAP (which, as noted, binds γ-COP) to trigger coat disassembly (pubmed.ncbi.nlm.nih.gov). This ensures COPI vesicles shed their coat and can fuse with target membranes (ER or Golgi). The COPI pathway also intersects with other trafficking routes; for instance, COPI-coated intermediates form at the ER-Golgi intermediate compartment (ERGIC) as well, and recent 3D electron microscopy showed COPI coats on vesicles carrying SARS-CoV-2 virions from the ERGIC to Golgi during infection (pubmed.ncbi.nlm.nih.gov) (pubmed.ncbi.nlm.nih.gov). Depleting coatomer components (e.g. COPB2) in infected cells causes nascent virions to be trapped in the ERGIC, blocking their export (pubmed.ncbi.nlm.nih.gov) (pubmed.ncbi.nlm.nih.gov). This exemplifies how fundamental COPI vesicle function, with γ2-COP as a part, is even hijacked in pathological contexts. In summary, COPG2 is integral to the COPI-mediated transport pathway, which is vital for recycling membrane proteins, maintaining organelle identity, and supporting various cellular processes that rely on correct protein localization.

Subcellular Localization and Expression

The γ2-COP protein is predominantly intracellular and cytosolic, with a dynamic association to Golgi membranes. Like all coatomer subunits, γ2-COP resides in the cytosol when not active, and upon ARF1 activation it localizes to the cytosolic face of the Golgi and ERGIC membranes to drive vesicle budding (pmc.ncbi.nlm.nih.gov). Immunolocalization studies have shown coatomer concentrated at the Golgi region as punctate perinuclear staining, corresponding to coatomer-coated vesicles and buds. The Human Protein Atlas reports that COPG2 shows ubiquitous cytoplasmic expression in most human tissues (www.proteinatlas.org), consistent with its housekeeping role in secretory trafficking. mRNA profiling indicates low tissue specificity – COPG2 is expressed in virtually all cell types at baseline (www.proteinatlas.org). Nonetheless, there are subtle variations: for example, single-cell RNA data show enhanced expression of COPG2 in certain neuron populations and germ cells (www.proteinatlas.org), and during mouse neuronal differentiation Copg2 expression tends to be down-regulated in mature neurons (relative to its paralog, see below) (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). Overall, the evidence suggests γ2-COP is broadly expressed and available in all cells, reflecting its fundamental role in general cell physiology.

At the subcellular level, γ2-COP (within coatomer) shuttles between the cytosol and Golgi/ERGIC membranes. Recruitment to membranes is transient – the coat assembles to form a vesicle and then disassembles after budding, returning coatomer subunits (including γ2-COP) to the cytoplasm (pubmed.ncbi.nlm.nih.gov) (pubmed.ncbi.nlm.nih.gov). This cyclical localization is regulated by ARF1’s GTP/GDP state. Notably, studies of coatomer isoforms revealed that distinct coatomer complexes can localize differently in cells: coatomer containing γ2-COP (paired with ζ1-COP) showed somewhat different steady-state distribution compared to complexes with γ1-COP (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). In rat liver cells, three coatomer isoform pools – γ1/ζ1, γ1/ζ2, and γ2/ζ1 – were identified in roughly a 2:1:2 ratio (pmc.ncbi.nlm.nih.gov). Intriguingly, the γ2/ζ1 coatomer isoform was found to concentrate on a specific subset of COPI vesicles (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov), implying that γ2-COP–containing coatomers might preferentially cycle on certain routes (for instance, specific retrograde carriers). These findings still await full mechanistic explanation, but they reinforce that γ2-COP localizes to COPI vesicles in vivo, potentially with a bias toward particular trafficking pathways (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). In summary, γ2-COP is an intracellular protein cycling between cytosol and Golgi membranes, present in essentially all cells to support vesicle transport.

Pathway Integration and Functional Insights from Research

For many years, γ1-COP and γ2-COP were assumed to be functionally redundant components of COPI. Indeed, core COPI functions (Golgi–ER transport, vesicle formation) can be carried out by coatomer containing either γ1 or γ2 subunits. Gene knockout experiments in mice and cell lines show that neither COPG1 (γ1) nor COPG2 (γ2) is individually essential for cell viability – loss of one paralog can be compensated by up-regulation of the other, allowing coatomer levels to be maintained (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). In pluripotent mouse cells, knocking out Copg2 alone still permits cell survival and basic secretory transport (γ1-COP levels increase in compensation), and vice versa (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). This indicates considerable redundancy: both γ-COP isoforms can fulfill the “essential functions” of the COPI coat (pmc.ncbi.nlm.nih.gov). However, emerging research has highlighted context-specific roles that distinguish the paralogs. A 2020 study by Goyal et al. found that during neuronal differentiation, the two isoforms are differentially expressed and have unique contributions (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). In mouse embryonic stem cells induced to form neurons, Copg1 (γ1) expression was strongly upregulated at the stage of mature neuron formation, whereas Copg2 was not (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). Functionally, loss of γ1-COP impaired neuronal outgrowth: Copg1 knockout cells formed fewer and shorter neurites upon differentiation (pmc.ncbi.nlm.nih.gov). In contrast, Copg2 knockout did not hinder neurite outgrowth or neuron formation in this model (pmc.ncbi.nlm.nih.gov). Even when γ2-COP was overexpressed or knocked into the Copg1 locus, it could not fully rescue the neurite extension phenotype, indicating that γ1-COP has a paralog-specific role in supporting neurite/polarization processes that γ2-COP cannot completely substitute (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). This was the first clear evidence of a functional divergence: COPG1/γ1 appears specialized for certain aspects of neuronal cell biology, whereas COPG2/γ2 plays a more general or supportive role (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). The mechanistic basis is still under investigation, but one hypothesis is that γ1-COP–containing coatomer might interact with specific cargo or adaptor proteins critical for neurite extension (or conversely, γ2-COP might direct vesicle traffic to slightly different destinations) (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov).

Aside from developmental contexts, coatomer subunits including γ-COP have been linked to human disease and cellular stress pathways. Mutations or dysregulation of COPI subunits can lead to tissue-specific disorders despite their housekeeping roles. For example, certain inherited mutations in other COPI subunits (β- or δ-COP) cause neurological and developmental syndromes, underscoring the importance of COPI in the nervous system (pmc.ncbi.nlm.nih.gov). Genome studies have occasionally flagged the COPG2 locus in disorders – it resides in a region implicated in Silver–Russell syndrome (a growth retardation condition involving imprinting abnormalities) (pubmed.ncbi.nlm.nih.gov) (pubmed.ncbi.nlm.nih.gov), and it was once examined as a candidate gene in autism due to its location on chromosome 7q32 (though no causative mutations were confirmed). In cancer biology, COPI components are being explored for their role in sustaining the heightened secretory demands of tumor cells. While γ2-COP itself has not been singled out as a frequent mutation target, the coatomer complex as a whole is required for rapidly proliferating cells; recent work showed certain cancer cells rely on the COPI zeta1 subunit (COPZ1) for survival, a concept termed “non-oncogene addiction” (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). It is conceivable that redundancy between γ1 and γ2 has so far masked any unique dependency on γ2 in such contexts. Nevertheless, COPG2’s contribution is indispensable in a general sense – at least one γ-COP isoform must be present for any cell to survive, given the essential nature of COPI trafficking (pmc.ncbi.nlm.nih.gov). In summary, contemporary research paints COPG2 as a broadly acting coat protein with some emerging specialized roles. Its primary function is structural: enabling COPI vesicle formation for retrograde transport. Through this activity, it indirectly influences numerous pathways (protein sorting, organelle homeostasis, signaling protein localization), but it does not appear to have a direct signaling or enzymatic role beyond vesicle coat dynamics. The ongoing dissection of γ1 vs γ2 functions – for instance in neurons – is shedding light on why two paralogs exist. It suggests that COPG2/γ2-COP may be optimized for routine housekeeping trafficking, whereas COPG1/γ1-COP might support trafficking demands in specialized cells or conditions (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). This nuanced understanding is still evolving, and future precise studies (e.g. proteomic cargo profiles of γ1- vs γ2-coatomers and knockout animal models) will further clarify COPG2’s specific role within the essential COPI machinery.

References: (Key references are provided for each claim in the text above, with publication year and source indicated where available.)

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43. AnnotationURLCitation(end_index=14943, start_index=14809, title='Coatomer complex I is required for the transport of SARS-CoV-2 progeny virions from the endoplasmic reticulum-Golgi intermediate compartment - PubMed', type='url_citation', url='https://pubmed.ncbi.nlm.nih.gov/39611845/#:~:text=as%20array%20tomography%20and%20electron,Hence%2C%20our')
44. AnnotationURLCitation(end_index=15044, start_index=14944, title='Coatomer complex I is required for the transport of SARS-CoV-2 progeny virions from the endoplasmic reticulum-Golgi intermediate compartment - PubMed', type='url_citation', url='https://pubmed.ncbi.nlm.nih.gov/39611845/#:~:text=virus%20replication,2')
45. AnnotationURLCitation(end_index=15464, start_index=15360, title='Novel Isotypic γ/ζ Subunits Reveal Three Coatomer Complexes in Mammals - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC321441/#:~:text=%CE%B31%2F%CE%B61,COP')
46. AnnotationURLCitation(end_index=15593, start_index=15465, title='Novel Isotypic γ/ζ Subunits Reveal Three Coatomer Complexes in Mammals - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC321441/#:~:text=In%20Fig,coatomer%20and%20thus%20resides%20in')
47. AnnotationURLCitation(end_index=15837, start_index=15713, title='Novel Isotypic γ/ζ Subunits Reveal Three Coatomer Complexes in Mammals - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC321441/#:~:text=match%20at%20L122%20%CE%B31%2F%CE%B61,COP')
48. AnnotationURLCitation(end_index=16112, start_index=15943, title='Novel Isotypic γ/ζ Subunits Reveal Three Coatomer Complexes in Mammals - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC321441/#:~:text=the%20complex%20defined%20by%20the,isotype%20is%20preferentially%20incorporated%20into')
49. AnnotationURLCitation(end_index=16217, start_index=16113, title='Novel Isotypic γ/ζ Subunits Reveal Three Coatomer Complexes in Mammals - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC321441/#:~:text=%CE%B31%2F%CE%B61,COP')
50. AnnotationURLCitation(end_index=16712, start_index=16543, title='Novel Isotypic γ/ζ Subunits Reveal Three Coatomer Complexes in Mammals - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC321441/#:~:text=the%20complex%20defined%20by%20the,isotype%20is%20preferentially%20incorporated%20into')
51. AnnotationURLCitation(end_index=16817, start_index=16713, title='Novel Isotypic γ/ζ Subunits Reveal Three Coatomer Complexes in Mammals - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC321441/#:~:text=%CE%B31%2F%CE%B61,COP')
52. AnnotationURLCitation(end_index=17715, start_index=17530, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=strongly%20affect%20the%20global%20expression,%E2%88%92%2F%E2%88%92%7D%20cells%20compared%20with%20WT')
53. AnnotationURLCitation(end_index=17866, start_index=17716, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=regulated,antibody%2C%20which%20specifically%20recognizes%20native')
54. AnnotationURLCitation(end_index=18208, start_index=18038, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=expression%20of%20several%20COP%20subunits,To%20verify%20whether%20coatomer%20subunits')
55. AnnotationURLCitation(end_index=18359, start_index=18209, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=regulated,antibody%2C%20which%20specifically%20recognizes%20native')
56. AnnotationURLCitation(end_index=18624, start_index=18480, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=As%20a%20functional%20COPI%20pathway,COP%20paralog%20is%20up')
57. AnnotationURLCitation(end_index=19048, start_index=18878, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=paralogous%20subunits%20of%20the%20protein,for%20distinct%20functions%20for%20coatomer')
58. AnnotationURLCitation(end_index=19207, start_index=19049, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=COPI%20pathway%20lead%20to%20specific,did%20not%20affect%20retinoic%20acid')
59. AnnotationURLCitation(end_index=19534, start_index=19378, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=Moreover%2C%20binding%20of%20%CE%B1,both%20gene%20disruptions%20led%20to')
60. AnnotationURLCitation(end_index=19660, start_index=19535, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=This%20is%20in%20contrast%20to,Altogether')
61. AnnotationURLCitation(end_index=19948, start_index=19798, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=Copg1%20or%20Copg2%20in%20P19,role%20of%20COPI%20vesicles%20during')
62. AnnotationURLCitation(end_index=20201, start_index=20051, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=Copg1%20or%20Copg2%20in%20P19,role%20of%20COPI%20vesicles%20during')
63. AnnotationURLCitation(end_index=20603, start_index=20473, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=viability,role%20of%20COPI%20vesicles%20during')
64. AnnotationURLCitation(end_index=20776, start_index=20604, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=formation%20of%20loose%20embryoid%20bodies,required%20to%20promote%20neurite%20outgrowth')
65. AnnotationURLCitation(end_index=21152, start_index=20976, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=the%20paralogous%20coatomer%20subunits%20%CE%B31,paralogous%20subunits%20in%20this%20process')
66. AnnotationURLCitation(end_index=21303, start_index=21153, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=Copg1%20or%20Copg2%20in%20P19,role%20of%20COPI%20vesicles%20during')
67. AnnotationURLCitation(end_index=21752, start_index=21585, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=through%20a%20combination%20of%20genome,paralogous%20subunits%20in%20this%20process')
68. AnnotationURLCitation(end_index=21857, start_index=21753, title='Novel Isotypic γ/ζ Subunits Reveal Three Coatomer Complexes in Mammals - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC321441/#:~:text=%CE%B31%2F%CE%B61,COP')
69. AnnotationURLCitation(end_index=22474, start_index=22298, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=Several%20lines%20of%20evidence%2C%20however%2C,mRNA%20expression%20profiling%20data%2C%20we')
70. AnnotationURLCitation(end_index=22821, start_index=22679, title='Tissue-specific alternative polyadenylation at the imprinted gene Mest regulates allelic usage at Copg2 - PubMed', type='url_citation', url='https://pubmed.ncbi.nlm.nih.gov/22053079/#:~:text=The%20gene%20Mest%20,into%20the%20downstream%20antisense%20gene')
71. AnnotationURLCitation(end_index=22983, start_index=22822, title='Tissue-specific alternative polyadenylation at the imprinted gene Mest regulates allelic usage at Copg2 - PubMed', type='url_citation', url='https://pubmed.ncbi.nlm.nih.gov/22053079/#:~:text=mouse%20and%20only%20the%20paternal,produced%20exclusively%20in%20the%20developing')
72. AnnotationURLCitation(end_index=23651, start_index=23547, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=article%20%5D%20,DOI')
73. AnnotationURLCitation(end_index=23741, start_index=23652, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=5,DOI')
74. AnnotationURLCitation(end_index=24195, start_index=24051, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=As%20a%20functional%20COPI%20pathway,COP%20paralog%20is%20up')
75. AnnotationURLCitation(end_index=25124, start_index=24948, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=the%20paralogous%20coatomer%20subunits%20%CE%B31,paralogous%20subunits%20in%20this%20process')
76. AnnotationURLCitation(end_index=25275, start_index=25125, title='A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC7368096/#:~:text=Copg1%20or%20Copg2%20in%20P19,role%20of%20COPI%20vesicles%20during')