GCN1

UniProt ID: Q92616
Organism: Homo sapiens
Review Status: COMPLETE
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Gene Description

GCN1 (stalled ribosome sensor GCN1, formerly GCN1L1) is a very large cytoplasmic HEAT-repeat/alpha-solenoid protein that binds directly to ribosomes and acts as a sentinel for stalled and collided ribosomes. Through its RWD-binding domain it engages RWD-domain proteins and serves two intertwined ribosome-surveillance functions. First, GCN1 activates the eIF2alpha kinase GCN2 (EIF2AK4) on translating ribosomes, stimulating GCN2 to phosphorylate eIF2alpha (EIF2S1) and thereby triggering the integrated stress response and the cellular response to amino-acid starvation (the GCN2-mediated signaling axis conserved from yeast GCN1/GCN20). Second, GCN1 is the collision sensor of the RNF14-RNF25 translation quality-control pathway, where it is required for ubiquitination and degradation of translation factors (eEF1A/eEF1A1, eRF1/ETF1) and ribosomal proteins on stalled ribosomes, including resolution of formaldehyde-induced mRNA RNA-protein crosslinks. GCN1 binding by IMPACT antagonizes GCN2 activation. GCN1 is ribosome/polysome-associated in the cytosol.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0006417 regulation of translation
IBA
GO_REF:0000033 		KEEP AS NON CORE
Summary: Broad phylogenetically inferred process term. GCN1's specific roles are activation of the GCN2/ISR pathway and collided-ribosome quality control; these down-regulate translation, but the broad term is non-specific.
Reason: Correct in direction but too general; the informative core roles (GCN2 activation/ISR and RQC) are captured by more specific terms.
Supporting Evidence:
file:human/GCN1/GCN1-goa.tsv
GO:0006417 regulation of translation biological_process ECO:0000318 IBA
GO:0019887 protein kinase regulator activity
IBA
GO_REF:0000033 		KEEP AS NON CORE
Summary: GCN1 regulates (activates) the protein kinase GCN2/EIF2AK4. This is a core molecular function, though the more specific protein serine/threonine kinase activator activity term is preferable.
Reason: Accurate but less specific than the protein serine/threonine kinase activator activity term that more precisely captures GCN1's activation of GCN2; retained as a valid parent.
Supporting Evidence:
file:human/GCN1/GCN1-uniprot.txt
stimulates EIF2AK4/GCN2 kinase activity, leading to phosphorylation of eukaryotic translation initiation factor 2
GO:0034198 cellular response to amino acid starvation
IBA
GO_REF:0000033 		ACCEPT
Summary: GCN1 mediates activation of GCN2 in response to amino-acid starvation, a conserved role (yeast GCN1/GCN20 -> GCN2 -> eIF2alpha -> GCN4/ATF4). This is a core biological process for GCN1.
Reason: Well-supported, conserved core role of GCN1 in the amino-acid starvation response via GCN2 activation.
Supporting Evidence:
file:human/GCN1/GCN1-uniprot.txt
positive activator of the integrated stress response (ISR) by mediating activation of EIF2AK4/GCN2 in response to amino acid starvation
GO:0005829 cytosol
IBA
GO_REF:0000033 		ACCEPT
Summary: GCN1 acts in the cytosol, associated with ribosomes/polysomes. Phylogenetically inferred and experimentally supported.
Reason: Correct site of action for this cytosolic ribosome-associated sensor.
Supporting Evidence:
file:human/GCN1/GCN1-uniprot.txt
SUBCELLULAR LOCATION: Cytoplasm
GO:0005737 cytoplasm
IEA
GO_REF:0000120 		ACCEPT
Summary: Electronic annotation of cytoplasmic localization, consistent with the documented cytoplasmic/ribosome-associated location of GCN1.
Reason: Correct compartment, corroborated by experimental and similarity evidence.
Supporting Evidence:
file:human/GCN1/GCN1-uniprot.txt
SUBCELLULAR LOCATION: Cytoplasm
GO:0005515 protein binding
IPI
PMID:17314511
Large-scale identification of c-MYC-associated proteins usin... 		KEEP AS NON CORE
Summary: c-MYC interactome (TAP/MudPIT) screen capturing a GCN1-MYC (P01106) interaction. GCN1 is a very large, abundant ribosome-associated protein; this isolated high-throughput interaction does not inform its core function.
Reason: Bare protein binding from a single large-scale affinity screen with a partner (MYC) unrelated to GCN1's ribosome-surveillance function; uninformative and not core.
Supporting Evidence:
file:human/GCN1/GCN1-goa.tsv
GO:0005515 protein binding molecular_function ECO:0000353 IPI PMID:17314511 UniProtKB:P01106
GO:0005515 protein binding
IPI
PMID:20936779
A human MAP kinase interactome. 		KEEP AS NON CORE
Summary: Human MAP kinase interactome screen capturing a GCN1-MYC (P01106) interaction. Isolated high-throughput interaction unrelated to GCN1's core function.
Reason: Bare protein binding from a high-throughput interactome with an unrelated partner; uninformative and not core.
Supporting Evidence:
file:human/GCN1/GCN1-goa.tsv
GO:0005515 protein binding molecular_function ECO:0000353 IPI PMID:20936779 UniProtKB:P01106
GO:0005515 protein binding
IPI
PMID:38884001
Mapping adipocyte interactome networks by HaloTag-enrichment... 		KEEP AS NON CORE
Summary: Adipocyte HaloTag-enrichment mass-spectrometry interactome capturing a GCN1-MYC (P01106) interaction. Isolated high-throughput interaction unrelated to GCN1's core function.
Reason: Bare protein binding from a high-throughput proteomic screen with an unrelated partner; uninformative and not core.
Supporting Evidence:
file:human/GCN1/GCN1-goa.tsv
GO:0005515 protein binding molecular_function ECO:0000353 IPI PMID:38884001 UniProtKB:P01106
GO:0034198 cellular response to amino acid starvation
IEA
GO_REF:0000107 		ACCEPT
Summary: Ortholog-based electronic annotation of the amino-acid starvation response, consistent with GCN1's conserved role in GCN2 activation.
Reason: Correct core biological process, corroborated by experimental/ISS evidence.
Supporting Evidence:
file:human/GCN1/GCN1-uniprot.txt
positive activator of the integrated stress response (ISR) by mediating activation of EIF2AK4/GCN2 in response to amino acid starvation
GO:0043539 protein serine/threonine kinase activator activity
IEA
GO_REF:0000107 		ACCEPT
Summary: GCN1 activates the serine/threonine kinase GCN2/EIF2AK4 on translating ribosomes, stimulating eIF2alpha phosphorylation. This is a core molecular function.
Reason: Precisely captures GCN1's core activity as an activator of the GCN2 protein serine/threonine kinase.
Supporting Evidence:
file:human/GCN1/GCN1-uniprot.txt
stimulates EIF2AK4/GCN2 kinase activity, leading to phosphorylation of eukaryotic translation initiation factor 2
GO:0140469 GCN2-mediated signaling
IEA
GO_REF:0000107 		ACCEPT
Summary: GCN1 is upstream activator of GCN2-mediated signaling. Core biological process capturing the ISR-activation role.
Reason: Directly reflects GCN1's role in stimulating GCN2 signaling; core process.
Supporting Evidence:
file:human/GCN1/GCN1-uniprot.txt
Interaction with EIF2AK4/GCN2 on translating ribosomes stimulates EIF2AK4/GCN2 kinase activity
GO:0005829 cytosol
IDA
GO_REF:0000052 		ACCEPT
Summary: Direct immunofluorescence (HPA) evidence for cytosolic localization, consistent with GCN1's ribosome-associated cytosolic location.
Reason: IDA-supported cytosolic localization matching the documented site of action.
Supporting Evidence:
file:human/GCN1/GCN1-goa.tsv
GO:0005829 cytosol cellular_component ECO:0000314 IDA GO_REF:0000052
GO:0022626 cytosolic ribosome
IDA
PMID:36638793
An E3 ligase network engages GCN1 to promote the degradation... 		ACCEPT
Summary: GCN1 is active on the cytosolic ribosome, where it senses collided ribosomes and engages RNF14. Direct experimental evidence.
Reason: Core cellular component/site of action; GCN1 binds and acts on cytosolic ribosomes.
Supporting Evidence:
PMID:36638793
GCN1 is a conserved ribosome-associated scaffolding protein that binds the RWD domain of the integrated stress response kinase, GCN2
GO:0170011 stalled ribosome sensor activity
IDA
PMID:36638793
An E3 ligase network engages GCN1 to promote the degradation... 		ACCEPT
Summary: GCN1 directly senses stalled/collided ribosomes (occluded A site) and recruits RNF14, triggering degradation of translation factors. This is the core molecular function of GCN1.
Reason: Directly demonstrated core MF; GCN1 is the ribosome collision sensor of the RNF14-RNF25 quality-control pathway.
Supporting Evidence:
PMID:36638793
The ribosome collision sensor GCN1 plays an
file:human/GCN1/GCN1-uniprot.txt
acts as a sentinel for colliding ribosomes
GO:0005737 cytoplasm
ISS
GO_REF:0000024 		ACCEPT
Summary: Sequence-similarity-based annotation of cytoplasmic localization, consistent with experimental evidence.
Reason: Correct compartment, corroborated by IDA evidence.
Supporting Evidence:
file:human/GCN1/GCN1-uniprot.txt
SUBCELLULAR LOCATION: Cytoplasm
GO:0160127 protein-RNA covalent cross-linking repair
IDA
PMID:37951215
K6-linked ubiquitylation marks formaldehyde-induced RNA-prot... 		ACCEPT
Summary: GCN1 is required for translation-coupled resolution of formaldehyde-induced mRNA RNA-protein crosslinks that stall ribosomes (RNF14/RNF25 pathway). A specific RQC-adjacent biological process.
Reason: GCN1's collision-sensing role is required for resolving ribosome stalls at RNA-protein crosslinks; supported by the companion RNF14 crosslink-resolution studies.
Supporting Evidence:
PMID:37951216
which also requires the ribosome collision sensor GCN1
file:human/GCN1/GCN1-goa.tsv
GO:0160127 protein-RNA covalent cross-linking repair biological_process ECO:0000314 IDA PMID:37951215
GO:0072344 rescue of stalled cytosolic ribosome
IDA
PMID:37651229
Drug-induced eRF1 degradation promotes readthrough and revea... 		ACCEPT
Summary: GCN1 functions in a branch of ribosome-associated quality control that rescues stalled ribosomes via RNF14/RNF25-mediated degradation of A-site-blocking factors (here eRF1). Core RQC biological process.
Reason: Directly supported role of GCN1 in stalled-ribosome rescue through the RNF14/RNF25 pathway.
Supporting Evidence:
PMID:37651229
activating a branch of the ribosome-associated quality control network, which involves the translational stress sensor GCN1 and the catalytic activity of the E3 ubiquitin ligases RNF14 and RNF25
GO:0072344 rescue of stalled cytosolic ribosome
IDA
PMID:37951215
K6-linked ubiquitylation marks formaldehyde-induced RNA-prot... 		ACCEPT
Summary: GCN1 is required for resolution of ribosomes stalled at formaldehyde-induced RNA-protein crosslinks (RNF14 pathway). Core RQC biological process.
Reason: Supported by the RNF14 crosslink-resolution studies that require the collision sensor GCN1.
Supporting Evidence:
PMID:37951216
which also requires the ribosome collision sensor GCN1
GO:0072344 rescue of stalled cytosolic ribosome
IDA
PMID:37951216
RNF14-dependent atypical ubiquitylation promotes translation... 		ACCEPT
Summary: RNF14-dependent atypical ubiquitylation promotes translation-coupled resolution of RNA-protein crosslinks and requires the ribosome collision sensor GCN1. Core RQC biological process.
Reason: Directly supported; GCN1 is required for RNF14/RNF25-mediated resolution of stalled ribosomes.
Supporting Evidence:
PMID:37951216
which also requires the ribosome collision sensor GCN1
GO:0170011 stalled ribosome sensor activity
IDA
PMID:37651229
Drug-induced eRF1 degradation promotes readthrough and revea... 		ACCEPT
Summary: GCN1 senses stalled ribosomes (here induced by eRF1 depletion/readthrough) to engage the RNF14/RNF25 RQC branch. Core molecular function.
Reason: Directly demonstrated core sensor MF in a second independent stalling context.
Supporting Evidence:
PMID:37651229
activating a branch of the ribosome-associated quality control network, which involves the translational stress sensor GCN1 and the catalytic activity of the E3 ubiquitin ligases RNF14 and RNF25
GO:0170011 stalled ribosome sensor activity
IDA
PMID:37951215
K6-linked ubiquitylation marks formaldehyde-induced RNA-prot... 		ACCEPT
Summary: GCN1 senses ribosomes stalled at formaldehyde-induced RNA-protein crosslinks. Core molecular function.
Reason: Directly supported core sensor MF in the RNA-protein crosslink stalling context.
Supporting Evidence:
PMID:37951216
which also requires the ribosome collision sensor GCN1
GO:0170011 stalled ribosome sensor activity
IDA
PMID:37951216
RNF14-dependent atypical ubiquitylation promotes translation... 		ACCEPT
Summary: GCN1 senses stalled/collided ribosomes in the RNF14-dependent crosslink-resolution pathway. Core molecular function.
Reason: Directly supported core sensor MF.
Supporting Evidence:
PMID:37951216
which also requires the ribosome collision sensor GCN1
GO:0043539 protein serine/threonine kinase activator activity
ISS
GO_REF:0000024 		ACCEPT
Summary: Sequence-similarity-based annotation of GCN2 (serine/threonine kinase) activator activity, consistent with the conserved GCN1->GCN2 activation role.
Reason: Core MF, corroborated by experimental and ortholog evidence.
Supporting Evidence:
file:human/GCN1/GCN1-uniprot.txt
stimulates EIF2AK4/GCN2 kinase activity, leading to phosphorylation of eukaryotic translation initiation factor 2
GO:0060090 molecular adaptor activity
IDA
PMID:36638793
An E3 ligase network engages GCN1 to promote the degradation... 		ACCEPT
Summary: GCN1 acts as a ribosome-associated scaffold/adaptor that, via its RWD-binding domain, brings RWD-domain partners (GCN2, RNF14, IMPACT) to stalled ribosomes. A reasonable molecular-function description of its scaffolding role.
Reason: GCN1 is described as a scaffolding protein that recruits RWD-domain effectors to the ribosome; adaptor activity captures this bridging function.
Supporting Evidence:
PMID:36638793
GCN1 is a conserved ribosome-associated scaffolding protein that binds the RWD domain of the integrated stress response kinase, GCN2
GO:0072344 rescue of stalled cytosolic ribosome
IDA
PMID:36638793
An E3 ligase network engages GCN1 to promote the degradation... 		ACCEPT
Summary: GCN1 senses stalled ribosomes and recruits RNF14 to ubiquitinate and degrade A-site-blocking translation factors (eEF1A), a stalled-ribosome rescue process. Core RQC biological process.
Reason: Directly demonstrated; GCN1 is essential for RNF14/RNF25-mediated rescue of stalled ribosomes.
Supporting Evidence:
PMID:36638793
interacts with RNF14 and is also essential for eEF1A degradation
GO:0140469 GCN2-mediated signaling
ISS
GO_REF:0000024 		ACCEPT
Summary: Sequence-similarity-based annotation of GCN1's role in GCN2-mediated signaling, consistent with experimental evidence.
Reason: Core process; GCN1 is the upstream activator of GCN2 signaling.
Supporting Evidence:
file:human/GCN1/GCN1-uniprot.txt
Interaction with EIF2AK4/GCN2 on translating ribosomes stimulates EIF2AK4/GCN2 kinase activity
GO:0045296 cadherin binding
HDA
PMID:25468996
E-cadherin interactome complexity and robustness resolved by... 		MARK AS OVER ANNOTATED
Summary: High-throughput quantitative proteomics of the E-cadherin interactome capturing GCN1. GCN1 is a very large, abundant ribosome-associated protein; this is a non-specific proximity/affinity capture, not a genuine cadherin-binding function.
Reason: HDA proteomic capture inconsistent with GCN1's known cytosolic ribosome-surveillance function; likely a non-specific co-purification.
Supporting Evidence:
file:human/GCN1/GCN1-goa.tsv
GO:0045296 cadherin binding molecular_function ECO:0007005 HDA PMID:25468996
GO:0016020 membrane
HDA
PMID:19946888
Defining the membrane proteome of NK cells. 		MARK AS OVER ANNOTATED
Summary: High-throughput NK-cell membrane proteome capture. GCN1 is a cytosolic ribosome-associated protein; membrane localization is inconsistent with its established biology.
Reason: HDA membrane-proteome capture conflicts with the well-documented cytosolic/ribosomal localization of GCN1; likely a contaminant in the membrane fraction.
Supporting Evidence:
file:human/GCN1/GCN1-goa.tsv
GO:0016020 membrane cellular_component ECO:0007005 HDA PMID:19946888
GO:0003723 RNA binding
HDA
PMID:22681889
The mRNA-bound proteome and its global occupancy profile on ... 		KEEP AS NON CORE
Summary: mRNA-interactome capture identifying GCN1 as an RNA-associated protein. GCN1 associates with ribosomes/rRNA and senses mRNA-bound stalled ribosomes, so some RNA association is expected, but the bare RNA binding term is non-specific and not the informative core function.
Reason: Plausible given ribosome/mRNA association, but uninformative relative to GCN1's core sensor/scaffold and kinase-activator roles.
Supporting Evidence:
file:human/GCN1/GCN1-goa.tsv
GO:0003723 RNA binding molecular_function ECO:0007005 HDA PMID:22681889
GO:0005737 cytoplasm
NAS
PMID:9234705
Evidence that GCN1 and GCN20, translational regulators of GC... 		ACCEPT
Summary: Non-traceable author statement of cytoplasmic localization from the classic yeast GCN1/GCN20 study, consistent with the documented cytoplasmic location.
Reason: Consistent with experimental and similarity evidence for cytoplasmic localization.
Supporting Evidence:
file:human/GCN1/GCN1-uniprot.txt
SUBCELLULAR LOCATION: Cytoplasm
GO:0005840 ribosome
NAS
PMID:9234705
Evidence that GCN1 and GCN20, translational regulators of GC... 		ACCEPT
Summary: Author statement that GCN1 (with GCN20) co-sediments with polysomes/80S ribosomes and functions on elongating ribosomes. Consistent with GCN1's ribosome-associated role.
Reason: Correct ribosome-associated localization, consistent with the cytosolic ribosome IDA annotation and GCN1's mechanism.
Supporting Evidence:
file:human/GCN1/GCN1-uniprot.txt
Associates with ribosomes
GO:0008135 translation factor activity, RNA binding
NAS
PMID:9234705
Evidence that GCN1 and GCN20, translational regulators of GC... 		MARK AS OVER ANNOTATED
Summary: Outdated framing of GCN1 as a translation factor from the 1997 yeast study. GCN1 is now understood as a ribosome collision sensor and scaffold/activator of GCN2, not a canonical translation factor.
Reason: GCN1's molecular function is better captured by stalled ribosome sensor activity and kinase activator activity; the generic translation-factor MF is a legacy over-annotation.
Supporting Evidence:
file:human/GCN1/GCN1-uniprot.txt
acts as a sentinel for colliding ribosomes

Core Functions

Ribosome collision/stall sensor that binds the ribosome and recognizes stalled and collided ribosomes (occluded A site), serving as the trigger for downstream quality-control and stress-response effectors via its RWD-binding domain.

Molecular Function:
stalled ribosome sensor activity
Cellular Locations:
cytosolic ribosome
Supporting Evidence:
  • file:human/GCN1/GCN1-uniprot.txt
    acts as a sentinel for colliding ribosomes
  • PMID:36638793
    GCN1 is a conserved ribosome-associated scaffolding protein that binds the RWD domain of the integrated stress response kinase, GCN2

Activator of the eIF2alpha kinase GCN2 (EIF2AK4) on translating ribosomes, stimulating GCN2 to phosphorylate eIF2alpha and thereby triggering the integrated stress response and the cellular response to amino-acid starvation.

Molecular Function:
protein serine/threonine kinase activator activity
Cellular Locations:
cytosol
Supporting Evidence:
  • file:human/GCN1/GCN1-uniprot.txt
    stimulates EIF2AK4/GCN2 kinase activity, leading to phosphorylation of eukaryotic translation initiation factor 2

Essential scaffold of the RNF14-RNF25 translation quality-control pathway, recruiting the E3 ligase RNF14 to stalled ribosomes to promote ubiquitination and degradation of A-site-blocking translation factors (eEF1A, eRF1) and rescue of stalled ribosomes.

Molecular Function:
molecular adaptor activity
Cellular Locations:
cytosolic ribosome
Supporting Evidence:
  • PMID:36638793
    interacts with RNF14 and is also essential for eEF1A degradation

References

GO_REF:0000024
Manual transfer of experimentally-verified manual GO annotation data to orthologs by curator judgment of sequence similarity
GO_REF:0000033
Annotation inferences using phylogenetic trees
GO_REF:0000052
Gene Ontology annotation based on curation of immunofluorescence data
GO_REF:0000107
Automatic transfer of experimentally verified manual GO annotation data to orthologs using Ensembl Compara
GO_REF:0000120
Combined Automated Annotation using Multiple IEA Methods
PMID:9234705
Evidence that GCN1 and GCN20, translational regulators of GCN4, function on elongating ribosomes in activation of eIF2alpha kinase GCN2.
  • GCN1 and GCN20 form a complex required for stimulation of GCN2 kinase activity under amino-acid starvation; they co-sediment with polysomes and 80S ribosomes and function on elongating ribosomes.
PMID:17314511
Large-scale identification of c-MYC-associated proteins using a combined TAP/MudPIT approach.
PMID:19946888
Defining the membrane proteome of NK cells.
PMID:20936779
A human MAP kinase interactome.
PMID:22681889
The mRNA-bound proteome and its global occupancy profile on protein-coding transcripts.
PMID:25468996
E-cadherin interactome complexity and robustness resolved by quantitative proteomics.
PMID:36638793
An E3 ligase network engages GCN1 to promote the degradation of translation factors on stalled ribosomes.
  • GCN1 is a ribosome collision sensor that interacts with RNF14 and is essential for ubiquitination and degradation of eEF1A (and other translation factors/ribosomal proteins) on stalled ribosomes with an occluded A site.
  • GCN1 is a conserved ribosome-associated scaffolding protein that binds the RWD domain of the GCN2 kinase; IMPACT competes for this interaction.
PMID:37651229
Drug-induced eRF1 degradation promotes readthrough and reveals a new branch of ribosome quality control.
  • Drug-induced stalling triggers a branch of ribosome-associated quality control involving the translational stress sensor GCN1 and the E3 ligases RNF14 and RNF25, leading to eRF1 degradation.
PMID:37951215
K6-linked ubiquitylation marks formaldehyde-induced RNA-protein crosslinks for resolution.
  • Formaldehyde-induced RNA-protein crosslinks in mRNA stall ribosomes and are marked by RNF14-catalyzed K6-linked ubiquitylation and resolved by VCP; GCN1 acts as the collision sensor in this pathway.
PMID:37951216
RNF14-dependent atypical ubiquitylation promotes translation-coupled resolution of RNA-protein crosslinks.
  • RNF14/RNF25-dependent ubiquitylation promotes translation-coupled resolution of RNA-protein crosslinks and requires the ribosome collision sensor GCN1.
PMID:38884001
Mapping adipocyte interactome networks by HaloTag-enrichment-mass spectrometry.

Suggested Questions for Experts

Q: What structural features distinguish GCN1's recognition of collided ribosomes that activate GCN2/ISR versus those that engage the RNF14-RNF25 degradation branch?

Q: How is the choice between GCN2-mediated ISR signaling and RNF14/RNF25-mediated factor degradation coordinated on the same stalled-ribosome substrate, and what determines the balance?

Q: Does IMPACT-mediated antagonism of GCN1-GCN2 binding also modulate the RNF14 quality-control branch?

Suggested Experiments

Experiment: Cryo-EM of GCN1 bound to collided (disome) ribosomes with and without GCN2, RNF14 or IMPACT to define how the HEAT-repeat solenoid and RWD-binding domain discriminate substrates and effectors.

Experiment: Degron/ubiquitination kinetics (eEF1A, eRF1) on stalled-ribosome reporters in GCN1-knockout versus wild-type cells to quantify GCN1's requirement across distinct stalling stimuli (poly(A), ternatin-4, formaldehyde RPCs, eRF1 depletion).

Experiment: Phospho-eIF2alpha and ATF4 reporter assays in GCN1-knockout cells under amino-acid starvation versus collision stress to dissect the GCN2-activation versus RQC functions of GCN1.

📚 Additional Documentation

Notes

(GCN1-notes.md)

GCN1 (Stalled ribosome sensor GCN1 / GCN1L1) research notes

Identity

  • UniProt Q92616; very large (~2671 aa) HEAT-repeat / alpha-solenoid ribosome-binding protein. GCN1 family. Has an RWD-binding domain (RWDBD).

Core function — two intertwined ribosome-surveillance roles

  1. Ribosome collision/stall sensor that activates the eIF2alpha kinase GCN2 (EIF2AK4) -> integrated stress response (ISR).
  2. [GCN1-uniprot.txt "Ribosome collision sensor that plays a key role in the RNF14-RNF25 translation quality control pathway"]
  3. [GCN1-uniprot.txt "acts as a sentinel for colliding ribosomes"]
  4. [GCN1-uniprot.txt "positive activator of the integrated stress response (ISR) by mediating activation of EIF2AK4/GCN2 in response to amino acid starvation"]
  5. [GCN1-uniprot.txt "Interaction with EIF2AK4/GCN2 on translating ribosomes stimulates EIF2AK4/GCN2 kinase activity, leading to phosphorylation of eukaryotic translation initiation factor 2"]
  6. Conserved from yeast: GCN1/GCN20 stimulate GCN2 on translating ribosomes. [PMID:9234705 title "Evidence that GCN1 and GCN20, translational regulators of GCN4, function on elongating ribosomes in activation of eIF2alpha kinase GCN2"]
  7. GCN1 binds the RWD domain of GCN2; IMPACT competes. PMID:36638793
  8. Ribosome collision sensor in the RNF14/RNF25 elongation-factor quality-control pathway (RQC).
  9. [PMID:36638793 title "An E3 ligase network engages GCN1 to promote the degradation of translation factors on stalled ribosomes"]
  10. PMID:36638793
  11. GCN1 required for resolution of mRNA-RNA-protein crosslink (RPC) stalls (RNF14/RNF25). PMID:37951216
  12. PMID:37651229

Localization

  • Cytoplasm; associates with ribosomes / cytosolic ribosome (polysomes, 80S). [GCN1-uniprot.txt "Associates with ribosomes"; PMID:9234705]
  • Membrane (HDA PMID:19946888) and cadherin binding (HDA PMID:25468996) and RNA binding (HDA PMID:22681889) are high-throughput proteomic/mRNA-interactome screens -> non-specific / over-annotation.

Annotation notes

  • GO:0170011 stalled ribosome sensor activity (IDA, multiple papers) = CORE MF.
  • GO:0043539 protein serine/threonine kinase activator activity (ISS/IEA) + GO:0019887 protein kinase regulator activity (IBA) = CORE MF (activates GCN2). Prefer the more specific kinase-activator term.
  • GO:0060090 molecular adaptor activity (IDA PMID:36638793) — GCN1 scaffolds GCN2/RNF14/IMPACT via RWDBD; reasonable, keep (adaptor/scaffold).
  • GO:0072344 rescue of stalled cytosolic ribosome (IDA x4) = CORE BP (RQC role).
  • GO:0140469 GCN2-mediated signaling (IEA/ISS) + GO:0034198 cellular response to amino acid starvation (IBA/IEA) = CORE/near-core BP (ISR activation).
  • GO:0006417 regulation of translation (IBA) — broad; keep non-core (the specific roles are GCN2 activation + RQC).
  • GO:0160127 protein-RNA covalent cross-linking repair (IDA PMID:37951215) — GCN1's role in resolving formaldehyde RPC stalls; keep (RQC-adjacent), non-core relative to the sensor MF.
  • protein binding IPI (PMID:17314511, 20936779, 38884001) all WITH MYC (P01106) — c-MYC interactome / adipocyte HaloMS screens; GCN1 is large & abundant; isolated HT, not core -> MARK_AS_OVER_ANNOTATED.
  • GO:0045296 cadherin binding (HDA) — proximity/affinity proteomics artifact -> MARK_AS_OVER_ANNOTATED.
  • GO:0016020 membrane (HDA) — over-annotation; GCN1 is cytosolic/ribosomal -> MARK_AS_OVER_ANNOTATED.
  • GO:0003723 RNA binding (HDA mRNA-interactome) — GCN1 binds ribosomes/rRNA contextually; bare RNA binding from HT capture, keep non-core.
  • GO:0008135 translation factor activity, RNA binding (NAS, 1997) — outdated framing; GCN1 is a sensor/scaffold, not a canonical translation factor -> MARK_AS_OVER_ANNOTATED.
  • GO:0005840 ribosome / GO:0022626 cytosolic ribosome (NAS/IDA) — correct CC (ribosome-associated). Accept.

Pn Notes

(GCN1-pn-notes.md)

GCN1 PN Consistency Notes

  • Generated: 2026-06-18
  • Project: PROTEOSTASIS
  • Scope: PN consistency rereview against local AIGR review and available deep-research artifacts
  • UniProt: Q92616
  • AIGR review status: COMPLETE
  • Review batch: proteostasis-batch-2026-06-07c
  • Batch change status: added

Source Files Checked

Deep Research Files

  • No *-deep-research*.md file found in this gene directory.

AIGR Review Snapshot

  • Description: GCN1 (stalled ribosome sensor GCN1, formerly GCN1L1) is a very large cytoplasmic HEAT-repeat/alpha-solenoid protein that binds directly to ribosomes and acts as a sentinel for stalled and collided ribosomes. Through its RWD-binding domain it engages RWD-domain proteins and serves two intertwined ribosome-surveillance functions. First, GCN1 activates the eIF2alpha kinase GCN2 (EIF2AK4) on translating ribosomes, stimulating GCN2 to phosphorylate eIF2alpha (EIF2S1) and thereby triggering the integrated stress response and the cellular response to amino-acid starvation (the GCN2-mediated signaling axis conserved from yeast GCN1/GCN20). Second, GCN1 is the collision sensor of the RNF14-RNF25 translation quality-control pathway, where it is required for ubiquitination and degradation of translation factors (eEF1A/eEF1A1, eRF1/ETF1) and ribosomal proteins on stalled ribosomes, including resolution of formaldehyde-induced mRNA RNA-protein crosslinks. GCN1 binding by IMPACT antagonizes GCN2 activation. GCN1 is ribosome/polysome-associated in the cytosol.
  • Existing/core annotation action counts: ACCEPT: 23; KEEP_AS_NON_CORE: 6; MARK_AS_OVER_ANNOTATED: 3

PN Consistency Summary

  • Consistency: Strong and well-aligned. Deep research, notes, and review all describe GCN1 as the ribosome collision/stall sensor with two roles: (1) activating GCN2/EIF2AK4 → eIF2alpha-P → ISR/amino-acid-starvation response, and (2) acting as the collision sensor of the RNF14-RNF25 RQC pathway that degrades A-site-blocking factors (eEF1A, eRF1). Review ACCEPTs GO:0034198 (aa starvation), GO:0140469 (GCN2-mediated signaling), GO:0072344 (rescue of stalled ribosome ×4), GO:0170011 (stalled ribosome sensor ×4), GO:0043539 (kinase activator), GO:0060090 (adaptor), GO:0160127 (protein-RNA crosslink repair). All four PN rows map onto biology the review independently asserts. No contradictions.
  • PN story / NEW pressure: PN's projected terms — GO:0006417 (regulation of translation, already_in_goa, KEEP_AS_NON_CORE in review), GO:0140467 (ISR signaling, entailed by closure; review uses the child GO:0140469 GCN2-mediated signaling), GO:0006515 (RQC umbrella, verified real), GO:0016567 (protein ubiquitination) — are all real and biology-consistent. GO:0016567 is the one term GCN1's review does NOT carry: GCN1 enables/promotes eEF1A ubiquitination by recruiting RNF14, but GCN1 is the sensor/scaffold, not itself a ubiquitin transferase, so a direct GO:0016567 on GCN1 over-reaches (the ubiquitination is RNF14's catalytic act; GCN1 is involved_in via GO:0072344/GO:0060090). Mostly already captured; GO:0016567 over-reaches for the sensor.
  • Evidence alignment: PN cites one title — "Ribosome binding protein GCN1 regulates the cell cycle and cell proliferation and is essential for the embryonic development of mice (PLOS Genetics)" — which is NOT among the review's references (the review uses 9234705, 36638793, 37651229, 37951215/6 for the sensor/RQC/ISR roles). Divergence: PN's cited paper covers a developmental/proliferation phenotype not used by the review; the mechanistic ISR/RQC evidence base differs.
  • Verdict: Highly consistent on core sensor/ISR/RQC biology; PN story already captured (review is more granular: GO:0140469, GO:0072344, GO:0170011). One over-reach. Recommended edits: [MAP] qualify the eEF1A-ubiquitination type→GO:0016567 projection — GCN1 promotes (does not catalyze) eEF1A ubiquitination; project as involved_in RQC (GO:0072344) rather than as GCN1's own protein-ubiquitination activity. [REF] consider adding the PN-cited GCN1 developmental PLOS Genetics paper to the review references (currently absent) or noting its relevance is non-core.

Full Consistency Review

  • UniProt: Q92616 · batch: proteostasis-batch-2026-06-07c · review status: COMPLETE
  • PN placement (4 rows): PN regulation|Translation regulator|Integrated stress response|EIF2AK4 modulator; Translation|...|Ribosome-associated QC|other RQC processes; Translation|...|Ribosome-associated QC|ubiquitination of eEF1A on stalled ribosomes; Autophagy-Lysosome Pathway|Autophagy gene expression|ATF4 transcriptional program|Nutrient sensing ; PN-node mapping: ISR group=mapped→GO:0140467; Translation-regulator class=mapped→GO:0006417; RQC group=mapped→GO:0006515; eEF1A-ubiq type=mapped→GO:0016567 (protein ubiquitination); ALP class context_only (GO:0010506); several types/branches no_mapping.
  • Consistency: Strong and well-aligned. Deep research, notes, and review all describe GCN1 as the ribosome collision/stall sensor with two roles: (1) activating GCN2/EIF2AK4 → eIF2alpha-P → ISR/amino-acid-starvation response, and (2) acting as the collision sensor of the RNF14-RNF25 RQC pathway that degrades A-site-blocking factors (eEF1A, eRF1). Review ACCEPTs GO:0034198 (aa starvation), GO:0140469 (GCN2-mediated signaling), GO:0072344 (rescue of stalled ribosome ×4), GO:0170011 (stalled ribosome sensor ×4), GO:0043539 (kinase activator), GO:0060090 (adaptor), GO:0160127 (protein-RNA crosslink repair). All four PN rows map onto biology the review independently asserts. No contradictions.
  • PN story / NEW pressure: PN's projected terms — GO:0006417 (regulation of translation, already_in_goa, KEEP_AS_NON_CORE in review), GO:0140467 (ISR signaling, entailed by closure; review uses the child GO:0140469 GCN2-mediated signaling), GO:0006515 (RQC umbrella, verified real), GO:0016567 (protein ubiquitination) — are all real and biology-consistent. GO:0016567 is the one term GCN1's review does NOT carry: GCN1 enables/promotes eEF1A ubiquitination by recruiting RNF14, but GCN1 is the sensor/scaffold, not itself a ubiquitin transferase, so a direct GO:0016567 on GCN1 over-reaches (the ubiquitination is RNF14's catalytic act; GCN1 is involved_in via GO:0072344/GO:0060090). Mostly already captured; GO:0016567 over-reaches for the sensor.
  • Mapping strategy: ISR group→GO:0140467 is broader than the review's GO:0140469 (a child) but defensible as the umbrella; not a TOMM20-style rejection. RQC group→GO:0006515 is fine (umbrella over GO:0072344). The eEF1A-ubiquitination type→GO:0016567 should be treated as a process GCN1 enables indirectly, not a direct MF/BP to project as GCN1's own activity.
  • Evidence alignment: PN cites one title — "Ribosome binding protein GCN1 regulates the cell cycle and cell proliferation and is essential for the embryonic development of mice (PLOS Genetics)" — which is NOT among the review's references (the review uses 9234705, 36638793, 37651229, 37951215/6 for the sensor/RQC/ISR roles). Divergence: PN's cited paper covers a developmental/proliferation phenotype not used by the review; the mechanistic ISR/RQC evidence base differs.
  • Verdict: Highly consistent on core sensor/ISR/RQC biology; PN story already captured (review is more granular: GO:0140469, GO:0072344, GO:0170011). One over-reach. Recommended edits: [MAP] qualify the eEF1A-ubiquitination type→GO:0016567 projection — GCN1 promotes (does not catalyze) eEF1A ubiquitination; project as involved_in RQC (GO:0072344) rather than as GCN1's own protein-ubiquitination activity. [REF] consider adding the PN-cited GCN1 developmental PLOS Genetics paper to the review references (currently absent) or noting its relevance is non-core.

PN Dossier Context

  • review_batch: proteostasis-batch-2026-06-07c
  • review_yaml: genes/human/GCN1/GCN1-ai-review.yaml
  • PN workbook rows: 4

PN row 1: PN regulation | Translation regulator | Integrated stress response | EIF2AK4 modulator

  • UniProt: Q92616
  • In branches: PN, TR, ALP
  • PN-node mapping records (path + ancestors):
    • [type] PN regulation|Translation regulator|Integrated stress response|EIF2AK4 modulator
      status=no_mapping scope= GO=[]
      rationale: Reviewed as a contextual PN bucket. The label is useful for curator triage, but no direct GO mapping is appropriate because propagation would add a process, activity, or localization not shared cleanly by all members.
    • [group] PN regulation|Translation regulator|Integrated stress response
      status=mapped scope=ok_for_propagation_to_go GO=[GO:0140467 integrated stress response signaling]
      rationale: This PN path covers translation-regulator components of the integrated stress response, including EIF2S1 phosphorylation control. These genes are participants in integrated stress response signaling, but the PN group is a mechanistic slice of the process rather than a GO-equivalent class.
    • [class] PN regulation|Translation regulator
      status=mapped scope=ok_for_propagation_to_go GO=[GO:0006417 regulation of translation]
      rationale: This PN class is the broad translation-regulatory bucket. GO regulation of translation is the conservative propagation target for the umbrella label.
    • [branch] PN regulation
      status=no_mapping scope= GO=[]
      rationale: Reviewed as a top-level PN branch. This is a systems/taxonomy umbrella, not a direct GO assertion; narrower child curations carry any propagating GO mappings.

PN row 2: Translation | Cytosolic translation | Ribosome-associated QC | other RQC processes

  • UniProt: Q92616
  • In branches: PN, TR, ALP
  • PN-node mapping records (path + ancestors):
    • [type] Translation|Cytosolic translation|Ribosome-associated QC|other RQC processes
      status=no_mapping scope= GO=[]
      rationale: Reviewed as a broad PN category rather than a single GO class. The member genes span multiple activities, complexes, or contexts, so direct propagation from this node would overstate the shared biology.
    • [group] Translation|Cytosolic translation|Ribosome-associated QC
      status=mapped scope=ok_for_propagation_to_go GO=[GO:0006515 protein quality control for misfolded or incompletely synthesized proteins]
      rationale: The PN ribosome-associated quality-control group covers surveillance and disposal of stalled or defective nascent-chain translation products. GO lacks a dedicated ribosome-associated QC term in the local cache, so the broader protein-quality-control process is the best supported target.
    • [class] Translation|Cytosolic translation
      status=context_only scope=too_broad_to_propagate GO=[GO:0002181 cytoplasmic translation]
      rationale: The PN class Cytosolic translation is centered on the cytoplasmic translation apparatus and process, but it also houses supporting machinery such as ribosome biogenesis factors. The GO process term is a useful high-level label for the class, but propagating it to all members would over-annotate genes whose PN placement is through assembly or maturation context rather than core cytoplasmic translation.
    • [branch] Translation
      status=context_only scope=too_broad_to_propagate GO=[GO:0006412 translation]
      rationale: The PN Translation branch is organized around the translation apparatus and immediately associated cotranslational quality-control systems. GO translation is the closest high-level process label, but the PN branch also contains adjacent machinery such as ribosome biogenesis and nascent-chain handling. Keeping this relationship is useful for interpretation, but it is too broad to project safely onto every member.

PN row 3: Translation | Cytosolic translation | Ribosome-associated QC | ubiquitination of eEF1A on stalled ribosomes

  • UniProt: Q92616
  • In branches: PN, TR, ALP
  • PN-node mapping records (path + ancestors):
    • [type] Translation|Cytosolic translation|Ribosome-associated QC|ubiquitination of eEF1A on stalled ribosomes
      status=mapped scope=ok_for_propagation_to_go GO=[GO:0016567 protein ubiquitination]
      rationale: This PN RQC type is a specific ubiquitination bucket for eEF1A on stalled ribosomes. Protein ubiquitination is the shared process target.
    • [group] Translation|Cytosolic translation|Ribosome-associated QC
      status=mapped scope=ok_for_propagation_to_go GO=[GO:0006515 protein quality control for misfolded or incompletely synthesized proteins]
      rationale: The PN ribosome-associated quality-control group covers surveillance and disposal of stalled or defective nascent-chain translation products. GO lacks a dedicated ribosome-associated QC term in the local cache, so the broader protein-quality-control process is the best supported target.
    • [class] Translation|Cytosolic translation
      status=context_only scope=too_broad_to_propagate GO=[GO:0002181 cytoplasmic translation]
      rationale: The PN class Cytosolic translation is centered on the cytoplasmic translation apparatus and process, but it also houses supporting machinery such as ribosome biogenesis factors. The GO process term is a useful high-level label for the class, but propagating it to all members would over-annotate genes whose PN placement is through assembly or maturation context rather than core cytoplasmic translation.
    • [branch] Translation
      status=context_only scope=too_broad_to_propagate GO=[GO:0006412 translation]
      rationale: The PN Translation branch is organized around the translation apparatus and immediately associated cotranslational quality-control systems. GO translation is the closest high-level process label, but the PN branch also contains adjacent machinery such as ribosome biogenesis and nascent-chain handling. Keeping this relationship is useful for interpretation, but it is too broad to project safely onto every member.

PN row 4: Autophagy-Lysosome Pathway | Autophagy gene expression | ATF4 transcriptional program | Nutrient sensing

  • UniProt: Q92616
  • In branches: PN, TR, ALP
  • Notes: Forms a complex with EIF2AK4 to facilitate delivery of uncharged tRNAs to the tRNA binding domain of EIF2AK4 during starvation thereby promoting its activation
  • PN references (titles):
    • Ribosome binding protein GCN1 regulates the cell cycle and cell proliferation and is essential for the embryonic development of mice | PLOS Genetics
  • PN-node mapping records (path + ancestors):
    • [type] Autophagy-Lysosome Pathway|Autophagy gene expression|ATF4 transcriptional program|Nutrient sensing
      status=no_mapping scope= GO=[]
      rationale: Reviewed as a contextual PN role. The label is useful for curator triage, but by itself does not support a universal GO assertion for all member genes beyond curated ancestor or child mappings.
    • [group] Autophagy-Lysosome Pathway|Autophagy gene expression|ATF4 transcriptional program
      status=no_mapping scope= GO=[]
      rationale: Reviewed as a broad PN taxonomy container. The descendants mix components, regulators, context labels, and mechanistic leaves, so propagation should come only from narrower curated nodes.
    • [class] Autophagy-Lysosome Pathway|Autophagy gene expression
      status=context_only scope=too_broad_to_propagate GO=[GO:0010506 regulation of autophagy]
      rationale: This class records autophagy-linked gene-expression programs, but many nodes are transcription program names or upstream modulators rather than direct GO regulation assertions. It is kept as context only; transcription factor or cofactor activities are mapped at narrower nodes.
    • [branch] Autophagy-Lysosome Pathway
      status=no_mapping scope= GO=[]
      rationale: Reviewed as the top-level PN branch. It is a project taxonomy umbrella rather than a direct GO assertion; all propagation must come from manually curated child nodes.

Projected GO annotations (5)

  • GO:0006417 regulation of translation | scope=ok_for_propagation_to_go | goa_status=already_in_goa_exact | from=PN regulation|Translation regulator
  • GO:0140467 integrated stress response signaling | scope=ok_for_propagation_to_go | goa_status=entailed_by_goa_closure | from=PN regulation|Translation regulator|Integrated stress response
  • GO:0006515 protein quality control for misfolded or incompletely synthesized proteins | scope=ok_for_propagation_to_go | goa_status=new_to_goa | from=Translation|Cytosolic translation|Ribosome-associated QC
  • GO:0006515 protein quality control for misfolded or incompletely synthesized proteins | scope=ok_for_propagation_to_go | goa_status=new_to_goa | from=Translation|Cytosolic translation|Ribosome-associated QC
  • GO:0016567 protein ubiquitination | scope=ok_for_propagation_to_go | goa_status=new_to_goa | from=Translation|Cytosolic translation|Ribosome-associated QC|ubiquitination of eEF1A on stalled ribosomes

Note

This file is generated from the current PROTEOSTASIS phase-1 dossier and local gene-review artifacts. Edit the source review, PN mapping, or dossier rather than this generated note when correcting the underlying curation.

📄 View Raw YAML

 
id: Q92616
gene_symbol: GCN1
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:9606
  label: Homo sapiens
description: GCN1 (stalled ribosome sensor GCN1, formerly GCN1L1) is a very large cytoplasmic HEAT-repeat/alpha-solenoid protein that binds directly to ribosomes and acts as a sentinel for stalled and collided ribosomes. Through its RWD-binding domain it engages RWD-domain proteins and serves two intertwined ribosome-surveillance functions. First, GCN1 activates the eIF2alpha kinase GCN2 (EIF2AK4) on translating ribosomes, stimulating GCN2 to phosphorylate eIF2alpha (EIF2S1) and thereby triggering the integrated stress response and the cellular response to amino-acid starvation (the GCN2-mediated signaling axis conserved from yeast GCN1/GCN20). Second, GCN1 is the collision sensor of the RNF14-RNF25 translation quality-control pathway, where it is required for ubiquitination and degradation of translation factors (eEF1A/eEF1A1, eRF1/ETF1) and ribosomal proteins on stalled ribosomes, including resolution of formaldehyde-induced mRNA RNA-protein crosslinks. GCN1 binding by IMPACT antagonizes GCN2 activation. GCN1 is ribosome/polysome-associated in the cytosol.
existing_annotations:
- term:
    id: GO:0006417
    label: regulation of translation
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: involved_in
  review:
    summary: Broad phylogenetically inferred process term. GCN1's specific roles are activation of the GCN2/ISR pathway and collided-ribosome quality control; these down-regulate translation, but the broad term is non-specific.
    action: KEEP_AS_NON_CORE
    reason: Correct in direction but too general; the informative core roles (GCN2 activation/ISR and RQC) are captured by more specific terms.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-goa.tsv
      supporting_text: GO:0006417 regulation of translation biological_process ECO:0000318 IBA
- term:
    id: GO:0019887
    label: protein kinase regulator activity
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: enables
  review:
    summary: GCN1 regulates (activates) the protein kinase GCN2/EIF2AK4. This is a core molecular function, though the more specific protein serine/threonine kinase activator activity term is preferable.
    action: KEEP_AS_NON_CORE
    reason: Accurate but less specific than the protein serine/threonine kinase activator activity term that more precisely captures GCN1's activation of GCN2; retained as a valid parent.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-uniprot.txt
      supporting_text: stimulates EIF2AK4/GCN2 kinase activity, leading to phosphorylation of eukaryotic translation initiation factor 2
- term:
    id: GO:0034198
    label: cellular response to amino acid starvation
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: involved_in
  review:
    summary: GCN1 mediates activation of GCN2 in response to amino-acid starvation, a conserved role (yeast GCN1/GCN20 -> GCN2 -> eIF2alpha -> GCN4/ATF4). This is a core biological process for GCN1.
    action: ACCEPT
    reason: Well-supported, conserved core role of GCN1 in the amino-acid starvation response via GCN2 activation.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-uniprot.txt
      supporting_text: positive activator of the integrated stress response (ISR) by mediating activation of EIF2AK4/GCN2 in response to amino acid starvation
- term:
    id: GO:0005829
    label: cytosol
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: is_active_in
  review:
    summary: GCN1 acts in the cytosol, associated with ribosomes/polysomes. Phylogenetically inferred and experimentally supported.
    action: ACCEPT
    reason: Correct site of action for this cytosolic ribosome-associated sensor.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: Cytoplasm'
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: located_in
  review:
    summary: Electronic annotation of cytoplasmic localization, consistent with the documented cytoplasmic/ribosome-associated location of GCN1.
    action: ACCEPT
    reason: Correct compartment, corroborated by experimental and similarity evidence.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: Cytoplasm'
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:17314511
  qualifier: enables
  review:
    summary: c-MYC interactome (TAP/MudPIT) screen capturing a GCN1-MYC (P01106) interaction. GCN1 is a very large, abundant ribosome-associated protein; this isolated high-throughput interaction does not inform its core function.
    action: KEEP_AS_NON_CORE
    reason: Bare protein binding from a single large-scale affinity screen with a partner (MYC) unrelated to GCN1's ribosome-surveillance function; uninformative and not core.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-goa.tsv
      supporting_text: GO:0005515 protein binding molecular_function ECO:0000353 IPI PMID:17314511 UniProtKB:P01106
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:20936779
  qualifier: enables
  review:
    summary: Human MAP kinase interactome screen capturing a GCN1-MYC (P01106) interaction. Isolated high-throughput interaction unrelated to GCN1's core function.
    action: KEEP_AS_NON_CORE
    reason: Bare protein binding from a high-throughput interactome with an unrelated partner; uninformative and not core.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-goa.tsv
      supporting_text: GO:0005515 protein binding molecular_function ECO:0000353 IPI PMID:20936779 UniProtKB:P01106
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:38884001
  qualifier: enables
  review:
    summary: Adipocyte HaloTag-enrichment mass-spectrometry interactome capturing a GCN1-MYC (P01106) interaction. Isolated high-throughput interaction unrelated to GCN1's core function.
    action: KEEP_AS_NON_CORE
    reason: Bare protein binding from a high-throughput proteomic screen with an unrelated partner; uninformative and not core.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-goa.tsv
      supporting_text: GO:0005515 protein binding molecular_function ECO:0000353 IPI PMID:38884001 UniProtKB:P01106
- term:
    id: GO:0034198
    label: cellular response to amino acid starvation
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: involved_in
  review:
    summary: Ortholog-based electronic annotation of the amino-acid starvation response, consistent with GCN1's conserved role in GCN2 activation.
    action: ACCEPT
    reason: Correct core biological process, corroborated by experimental/ISS evidence.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-uniprot.txt
      supporting_text: positive activator of the integrated stress response (ISR) by mediating activation of EIF2AK4/GCN2 in response to amino acid starvation
- term:
    id: GO:0043539
    label: protein serine/threonine kinase activator activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: enables
  review:
    summary: GCN1 activates the serine/threonine kinase GCN2/EIF2AK4 on translating ribosomes, stimulating eIF2alpha phosphorylation. This is a core molecular function.
    action: ACCEPT
    reason: Precisely captures GCN1's core activity as an activator of the GCN2 protein serine/threonine kinase.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-uniprot.txt
      supporting_text: stimulates EIF2AK4/GCN2 kinase activity, leading to phosphorylation of eukaryotic translation initiation factor 2
- term:
    id: GO:0140469
    label: GCN2-mediated signaling
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: involved_in
  review:
    summary: GCN1 is upstream activator of GCN2-mediated signaling. Core biological process capturing the ISR-activation role.
    action: ACCEPT
    reason: Directly reflects GCN1's role in stimulating GCN2 signaling; core process.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-uniprot.txt
      supporting_text: Interaction with EIF2AK4/GCN2 on translating ribosomes stimulates EIF2AK4/GCN2 kinase activity
- term:
    id: GO:0005829
    label: cytosol
  evidence_type: IDA
  original_reference_id: GO_REF:0000052
  qualifier: located_in
  review:
    summary: Direct immunofluorescence (HPA) evidence for cytosolic localization, consistent with GCN1's ribosome-associated cytosolic location.
    action: ACCEPT
    reason: IDA-supported cytosolic localization matching the documented site of action.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-goa.tsv
      supporting_text: GO:0005829 cytosol cellular_component ECO:0000314 IDA GO_REF:0000052
- term:
    id: GO:0022626
    label: cytosolic ribosome
  evidence_type: IDA
  original_reference_id: PMID:36638793
  qualifier: is_active_in
  review:
    summary: GCN1 is active on the cytosolic ribosome, where it senses collided ribosomes and engages RNF14. Direct experimental evidence.
    action: ACCEPT
    reason: Core cellular component/site of action; GCN1 binds and acts on cytosolic ribosomes.
    supported_by:
    - reference_id: PMID:36638793
      supporting_text: GCN1 is a conserved ribosome-associated scaffolding protein that binds the RWD domain of the integrated stress response kinase, GCN2
- term:
    id: GO:0170011
    label: stalled ribosome sensor activity
  evidence_type: IDA
  original_reference_id: PMID:36638793
  qualifier: enables
  review:
    summary: GCN1 directly senses stalled/collided ribosomes (occluded A site) and recruits RNF14, triggering degradation of translation factors. This is the core molecular function of GCN1.
    action: ACCEPT
    reason: Directly demonstrated core MF; GCN1 is the ribosome collision sensor of the RNF14-RNF25 quality-control pathway.
    supported_by:
    - reference_id: PMID:36638793
      supporting_text: The ribosome collision sensor GCN1 plays an
    - reference_id: file:human/GCN1/GCN1-uniprot.txt
      supporting_text: acts as a sentinel for colliding ribosomes
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  qualifier: located_in
  review:
    summary: Sequence-similarity-based annotation of cytoplasmic localization, consistent with experimental evidence.
    action: ACCEPT
    reason: Correct compartment, corroborated by IDA evidence.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: Cytoplasm'
- term:
    id: GO:0160127
    label: protein-RNA covalent cross-linking repair
  evidence_type: IDA
  original_reference_id: PMID:37951215
  qualifier: involved_in
  review:
    summary: GCN1 is required for translation-coupled resolution of formaldehyde-induced mRNA RNA-protein crosslinks that stall ribosomes (RNF14/RNF25 pathway). A specific RQC-adjacent biological process.
    action: ACCEPT
    reason: GCN1's collision-sensing role is required for resolving ribosome stalls at RNA-protein crosslinks; supported by the companion RNF14 crosslink-resolution studies.
    supported_by:
    - reference_id: PMID:37951216
      supporting_text: which also requires the ribosome collision sensor GCN1
    - reference_id: file:human/GCN1/GCN1-goa.tsv
      supporting_text: GO:0160127 protein-RNA covalent cross-linking repair biological_process ECO:0000314 IDA PMID:37951215
- term:
    id: GO:0072344
    label: rescue of stalled cytosolic ribosome
  evidence_type: IDA
  original_reference_id: PMID:37651229
  qualifier: involved_in
  review:
    summary: GCN1 functions in a branch of ribosome-associated quality control that rescues stalled ribosomes via RNF14/RNF25-mediated degradation of A-site-blocking factors (here eRF1). Core RQC biological process.
    action: ACCEPT
    reason: Directly supported role of GCN1 in stalled-ribosome rescue through the RNF14/RNF25 pathway.
    supported_by:
    - reference_id: PMID:37651229
      supporting_text: activating a branch of the ribosome-associated quality control network, which involves the translational stress sensor GCN1 and the catalytic activity of the E3 ubiquitin ligases RNF14 and RNF25
- term:
    id: GO:0072344
    label: rescue of stalled cytosolic ribosome
  evidence_type: IDA
  original_reference_id: PMID:37951215
  qualifier: involved_in
  review:
    summary: GCN1 is required for resolution of ribosomes stalled at formaldehyde-induced RNA-protein crosslinks (RNF14 pathway). Core RQC biological process.
    action: ACCEPT
    reason: Supported by the RNF14 crosslink-resolution studies that require the collision sensor GCN1.
    supported_by:
    - reference_id: PMID:37951216
      supporting_text: which also requires the ribosome collision sensor GCN1
- term:
    id: GO:0072344
    label: rescue of stalled cytosolic ribosome
  evidence_type: IDA
  original_reference_id: PMID:37951216
  qualifier: involved_in
  review:
    summary: RNF14-dependent atypical ubiquitylation promotes translation-coupled resolution of RNA-protein crosslinks and requires the ribosome collision sensor GCN1. Core RQC biological process.
    action: ACCEPT
    reason: Directly supported; GCN1 is required for RNF14/RNF25-mediated resolution of stalled ribosomes.
    supported_by:
    - reference_id: PMID:37951216
      supporting_text: which also requires the ribosome collision sensor GCN1
- term:
    id: GO:0170011
    label: stalled ribosome sensor activity
  evidence_type: IDA
  original_reference_id: PMID:37651229
  qualifier: enables
  review:
    summary: GCN1 senses stalled ribosomes (here induced by eRF1 depletion/readthrough) to engage the RNF14/RNF25 RQC branch. Core molecular function.
    action: ACCEPT
    reason: Directly demonstrated core sensor MF in a second independent stalling context.
    supported_by:
    - reference_id: PMID:37651229
      supporting_text: activating a branch of the ribosome-associated quality control network, which involves the translational stress sensor GCN1 and the catalytic activity of the E3 ubiquitin ligases RNF14 and RNF25
- term:
    id: GO:0170011
    label: stalled ribosome sensor activity
  evidence_type: IDA
  original_reference_id: PMID:37951215
  qualifier: enables
  review:
    summary: GCN1 senses ribosomes stalled at formaldehyde-induced RNA-protein crosslinks. Core molecular function.
    action: ACCEPT
    reason: Directly supported core sensor MF in the RNA-protein crosslink stalling context.
    supported_by:
    - reference_id: PMID:37951216
      supporting_text: which also requires the ribosome collision sensor GCN1
- term:
    id: GO:0170011
    label: stalled ribosome sensor activity
  evidence_type: IDA
  original_reference_id: PMID:37951216
  qualifier: enables
  review:
    summary: GCN1 senses stalled/collided ribosomes in the RNF14-dependent crosslink-resolution pathway. Core molecular function.
    action: ACCEPT
    reason: Directly supported core sensor MF.
    supported_by:
    - reference_id: PMID:37951216
      supporting_text: which also requires the ribosome collision sensor GCN1
- term:
    id: GO:0043539
    label: protein serine/threonine kinase activator activity
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  qualifier: enables
  review:
    summary: Sequence-similarity-based annotation of GCN2 (serine/threonine kinase) activator activity, consistent with the conserved GCN1->GCN2 activation role.
    action: ACCEPT
    reason: Core MF, corroborated by experimental and ortholog evidence.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-uniprot.txt
      supporting_text: stimulates EIF2AK4/GCN2 kinase activity, leading to phosphorylation of eukaryotic translation initiation factor 2
- term:
    id: GO:0060090
    label: molecular adaptor activity
  evidence_type: IDA
  original_reference_id: PMID:36638793
  qualifier: enables
  review:
    summary: GCN1 acts as a ribosome-associated scaffold/adaptor that, via its RWD-binding domain, brings RWD-domain partners (GCN2, RNF14, IMPACT) to stalled ribosomes. A reasonable molecular-function description of its scaffolding role.
    action: ACCEPT
    reason: GCN1 is described as a scaffolding protein that recruits RWD-domain effectors to the ribosome; adaptor activity captures this bridging function.
    supported_by:
    - reference_id: PMID:36638793
      supporting_text: GCN1 is a conserved ribosome-associated scaffolding protein that binds the RWD domain of the integrated stress response kinase, GCN2
- term:
    id: GO:0072344
    label: rescue of stalled cytosolic ribosome
  evidence_type: IDA
  original_reference_id: PMID:36638793
  qualifier: involved_in
  review:
    summary: GCN1 senses stalled ribosomes and recruits RNF14 to ubiquitinate and degrade A-site-blocking translation factors (eEF1A), a stalled-ribosome rescue process. Core RQC biological process.
    action: ACCEPT
    reason: Directly demonstrated; GCN1 is essential for RNF14/RNF25-mediated rescue of stalled ribosomes.
    supported_by:
    - reference_id: PMID:36638793
      supporting_text: interacts with RNF14 and is also essential for eEF1A degradation
- term:
    id: GO:0140469
    label: GCN2-mediated signaling
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  qualifier: involved_in
  review:
    summary: Sequence-similarity-based annotation of GCN1's role in GCN2-mediated signaling, consistent with experimental evidence.
    action: ACCEPT
    reason: Core process; GCN1 is the upstream activator of GCN2 signaling.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-uniprot.txt
      supporting_text: Interaction with EIF2AK4/GCN2 on translating ribosomes stimulates EIF2AK4/GCN2 kinase activity
- term:
    id: GO:0045296
    label: cadherin binding
  evidence_type: HDA
  original_reference_id: PMID:25468996
  qualifier: enables
  review:
    summary: High-throughput quantitative proteomics of the E-cadherin interactome capturing GCN1. GCN1 is a very large, abundant ribosome-associated protein; this is a non-specific proximity/affinity capture, not a genuine cadherin-binding function.
    action: MARK_AS_OVER_ANNOTATED
    reason: HDA proteomic capture inconsistent with GCN1's known cytosolic ribosome-surveillance function; likely a non-specific co-purification.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-goa.tsv
      supporting_text: GO:0045296 cadherin binding molecular_function ECO:0007005 HDA PMID:25468996
- term:
    id: GO:0016020
    label: membrane
  evidence_type: HDA
  original_reference_id: PMID:19946888
  qualifier: located_in
  review:
    summary: High-throughput NK-cell membrane proteome capture. GCN1 is a cytosolic ribosome-associated protein; membrane localization is inconsistent with its established biology.
    action: MARK_AS_OVER_ANNOTATED
    reason: HDA membrane-proteome capture conflicts with the well-documented cytosolic/ribosomal localization of GCN1; likely a contaminant in the membrane fraction.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-goa.tsv
      supporting_text: GO:0016020 membrane cellular_component ECO:0007005 HDA PMID:19946888
- term:
    id: GO:0003723
    label: RNA binding
  evidence_type: HDA
  original_reference_id: PMID:22681889
  qualifier: enables
  review:
    summary: mRNA-interactome capture identifying GCN1 as an RNA-associated protein. GCN1 associates with ribosomes/rRNA and senses mRNA-bound stalled ribosomes, so some RNA association is expected, but the bare RNA binding term is non-specific and not the informative core function.
    action: KEEP_AS_NON_CORE
    reason: Plausible given ribosome/mRNA association, but uninformative relative to GCN1's core sensor/scaffold and kinase-activator roles.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-goa.tsv
      supporting_text: GO:0003723 RNA binding molecular_function ECO:0007005 HDA PMID:22681889
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: NAS
  original_reference_id: PMID:9234705
  qualifier: located_in
  review:
    summary: Non-traceable author statement of cytoplasmic localization from the classic yeast GCN1/GCN20 study, consistent with the documented cytoplasmic location.
    action: ACCEPT
    reason: Consistent with experimental and similarity evidence for cytoplasmic localization.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: Cytoplasm'
- term:
    id: GO:0005840
    label: ribosome
  evidence_type: NAS
  original_reference_id: PMID:9234705
  qualifier: located_in
  review:
    summary: Author statement that GCN1 (with GCN20) co-sediments with polysomes/80S ribosomes and functions on elongating ribosomes. Consistent with GCN1's ribosome-associated role.
    action: ACCEPT
    reason: Correct ribosome-associated localization, consistent with the cytosolic ribosome IDA annotation and GCN1's mechanism.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-uniprot.txt
      supporting_text: Associates with ribosomes
- term:
    id: GO:0008135
    label: translation factor activity, RNA binding
  evidence_type: NAS
  original_reference_id: PMID:9234705
  qualifier: enables
  review:
    summary: Outdated framing of GCN1 as a translation factor from the 1997 yeast study. GCN1 is now understood as a ribosome collision sensor and scaffold/activator of GCN2, not a canonical translation factor.
    action: MARK_AS_OVER_ANNOTATED
    reason: GCN1's molecular function is better captured by stalled ribosome sensor activity and kinase activator activity; the generic translation-factor MF is a legacy over-annotation.
    supported_by:
    - reference_id: file:human/GCN1/GCN1-uniprot.txt
      supporting_text: acts as a sentinel for colliding ribosomes
references:
- id: GO_REF:0000024
  title: Manual transfer of experimentally-verified manual GO annotation data to orthologs by curator judgment of sequence similarity
  findings: []
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings: []
- id: GO_REF:0000052
  title: Gene Ontology annotation based on curation of immunofluorescence data
  findings: []
- id: GO_REF:0000107
  title: Automatic transfer of experimentally verified manual GO annotation data to orthologs using Ensembl Compara
  findings: []
- id: GO_REF:0000120
  title: Combined Automated Annotation using Multiple IEA Methods
  findings: []
- id: PMID:9234705
  title: Evidence that GCN1 and GCN20, translational regulators of GCN4, function on elongating ribosomes in activation of eIF2alpha kinase GCN2.
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: "Cached publications/PMID_9234705.md title matches YAML; foundational
      (yeast) evidence that GCN1 stimulates the eIF2alpha kinase GCN2 on ribosomes,
      supporting the core kinase-activator function. GOA anchors this PMID to GO:0008135
      (NAS) and ribosome localization."
  findings:
  - statement: GCN1 and GCN20 form a complex required for stimulation of GCN2 kinase activity under amino-acid starvation; they co-sediment with polysomes and 80S ribosomes and function on elongating ribosomes.
    reference_section_type: ABSTRACT
- id: PMID:17314511
  title: Large-scale identification of c-MYC-associated proteins using a combined TAP/MudPIT approach.
  findings: []
- id: PMID:19946888
  title: Defining the membrane proteome of NK cells.
  findings: []
- id: PMID:20936779
  title: A human MAP kinase interactome.
  findings: []
- id: PMID:22681889
  title: The mRNA-bound proteome and its global occupancy profile on protein-coding transcripts.
  findings: []
- id: PMID:25468996
  title: E-cadherin interactome complexity and robustness resolved by quantitative proteomics.
  findings: []
- id: PMID:36638793
  title: An E3 ligase network engages GCN1 to promote the degradation of translation factors on stalled ribosomes.
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: "Cached publications/PMID_36638793.md title matches YAML; establishes
      the human core functions — GCN1 as a ribosome-collision sensor and RNF14 adaptor.
      GOA anchors this PMID to GO:0170011 (stalled ribosome sensor activity), GO:0060090
      (molecular adaptor activity) and GO:0072344 (rescue of stalled ribosome), all IDA."
  findings:
  - statement: GCN1 is a ribosome collision sensor that interacts with RNF14 and is essential for ubiquitination and degradation of eEF1A (and other translation factors/ribosomal proteins) on stalled ribosomes with an occluded A site.
    reference_section_type: ABSTRACT
  - statement: GCN1 is a conserved ribosome-associated scaffolding protein that binds the RWD domain of the GCN2 kinase; IMPACT competes for this interaction.
    reference_section_type: RESULTS
- id: PMID:37651229
  title: Drug-induced eRF1 degradation promotes readthrough and reveals a new branch of ribosome quality control.
  findings:
  - statement: Drug-induced stalling triggers a branch of ribosome-associated quality control involving the translational stress sensor GCN1 and the E3 ligases RNF14 and RNF25, leading to eRF1 degradation.
    reference_section_type: ABSTRACT
- id: PMID:37951215
  title: K6-linked ubiquitylation marks formaldehyde-induced RNA-protein crosslinks for resolution.
  findings:
  - statement: Formaldehyde-induced RNA-protein crosslinks in mRNA stall ribosomes and are marked by RNF14-catalyzed K6-linked ubiquitylation and resolved by VCP; GCN1 acts as the collision sensor in this pathway.
    reference_section_type: ABSTRACT
- id: PMID:37951216
  title: RNF14-dependent atypical ubiquitylation promotes translation-coupled resolution of RNA-protein crosslinks.
  findings:
  - statement: RNF14/RNF25-dependent ubiquitylation promotes translation-coupled resolution of RNA-protein crosslinks and requires the ribosome collision sensor GCN1.
    reference_section_type: RESULTS
- id: PMID:38884001
  title: Mapping adipocyte interactome networks by HaloTag-enrichment-mass spectrometry.
  findings: []
core_functions:
- description: Ribosome collision/stall sensor that binds the ribosome and recognizes stalled and collided ribosomes (occluded A site), serving as the trigger for downstream quality-control and stress-response effectors via its RWD-binding domain.
  molecular_function:
    id: GO:0170011
    label: stalled ribosome sensor activity
  locations:
  - id: GO:0022626
    label: cytosolic ribosome
  supported_by:
  - reference_id: file:human/GCN1/GCN1-uniprot.txt
    supporting_text: acts as a sentinel for colliding ribosomes
  - reference_id: PMID:36638793
    supporting_text: GCN1 is a conserved ribosome-associated scaffolding protein that binds the RWD domain of the integrated stress response kinase, GCN2
- description: Activator of the eIF2alpha kinase GCN2 (EIF2AK4) on translating ribosomes, stimulating GCN2 to phosphorylate eIF2alpha and thereby triggering the integrated stress response and the cellular response to amino-acid starvation.
  molecular_function:
    id: GO:0043539
    label: protein serine/threonine kinase activator activity
  locations:
  - id: GO:0005829
    label: cytosol
  supported_by:
  - reference_id: file:human/GCN1/GCN1-uniprot.txt
    supporting_text: stimulates EIF2AK4/GCN2 kinase activity, leading to phosphorylation of eukaryotic translation initiation factor 2
- description: Essential scaffold of the RNF14-RNF25 translation quality-control pathway, recruiting the E3 ligase RNF14 to stalled ribosomes to promote ubiquitination and degradation of A-site-blocking translation factors (eEF1A, eRF1) and rescue of stalled ribosomes.
  molecular_function:
    id: GO:0060090
    label: molecular adaptor activity
  locations:
  - id: GO:0022626
    label: cytosolic ribosome
  supported_by:
  - reference_id: PMID:36638793
    supporting_text: interacts with RNF14 and is also essential for eEF1A degradation
proposed_new_terms: []
suggested_questions:
- question: What structural features distinguish GCN1's recognition of collided ribosomes that activate GCN2/ISR versus those that engage the RNF14-RNF25 degradation branch?
- question: How is the choice between GCN2-mediated ISR signaling and RNF14/RNF25-mediated factor degradation coordinated on the same stalled-ribosome substrate, and what determines the balance?
- question: Does IMPACT-mediated antagonism of GCN1-GCN2 binding also modulate the RNF14 quality-control branch?
suggested_experiments:
- description: Cryo-EM of GCN1 bound to collided (disome) ribosomes with and without GCN2, RNF14 or IMPACT to define how the HEAT-repeat solenoid and RWD-binding domain discriminate substrates and effectors.
- description: Degron/ubiquitination kinetics (eEF1A, eRF1) on stalled-ribosome reporters in GCN1-knockout versus wild-type cells to quantify GCN1's requirement across distinct stalling stimuli (poly(A), ternatin-4, formaldehyde RPCs, eRF1 depletion).
- description: Phospho-eIF2alpha and ATF4 reporter assays in GCN1-knockout cells under amino-acid starvation versus collision stress to dissect the GCN2-activation versus RQC functions of GCN1.