Organellar GatC subunit of the GatCAB amidotransferase complex that forms correctly charged Gln-tRNA(Gln) by transamidation in chloroplasts and mitochondria.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005739 mitochondrion | IBA GO_REF:0000033 | ACCEPT | Summary: mitochondrion localization is supported for organellar GatC. Reason: UniProt places GatC in both mitochondrion and chloroplast, and comparative plant evidence shows that plant GatCAB subunits (including GatC) are dual-targeted to both organelles by in vitro import assays in Arabidopsis. Supporting Evidence: file:POPTR/GATC/GATC-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion file:POPTR/GATC/GATC-deep-research-falcon.md GatA, GatB, and GatC** are imported into **both mitochondria and chloroplasts** and processed to mature, protease-protected forms |
| GO:0030956 glutamyl-tRNA(Gln) amidotransferase complex | IBA GO_REF:0000033 | ACCEPT | Summary: GatC is part of the glutamyl-tRNA(Gln) amidotransferase complex. Reason: The protein is a subunit of the heterotrimeric GatCAB amidotransferase complex; in the conserved and plant enzymes GatC is the small accessory/structural subunit that stabilizes the GatA/GatB catalytic core. Supporting Evidence: file:POPTR/GATC/GATC-uniprot.txt Subunit of the heterotrimeric GatCAB amidotransferase (AdT) complex, composed of A, B and C subunits. file:POPTR/GATC/GATC-deep-research-falcon.md GatC as a **structural/linker** element that interacts with GatA and GatB via its termini |
| GO:0032543 mitochondrial translation | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: Mitochondrial translation is a valid organellar process consequence of Gln-tRNA(Gln) formation but is not the most direct function. Reason: The direct function is tRNA-dependent glutamine formation by transamidation; supplying correctly charged Gln-tRNA(Gln) to organellar ribosomes (mitochondrial translation) is the downstream consequence. Supporting Evidence: file:POPTR/GATC/GATC-uniprot.txt Allows the formation of correctly charged Gln-tRNA(Gln) through the transamidation of misacylated Glu-tRNA(Gln) in chloroplasts and mitochondria. file:POPTR/GATC/GATC-deep-research-falcon.md GatCAB sits in the **organellar translation supply chain**, upstream of ribosomal protein synthesis |
| GO:0070681 glutaminyl-tRNAGln biosynthesis via transamidation | IBA GO_REF:0000033 | MODIFY | Summary: Retain the supported biology under the current process term; the source GO identifier is obsolete. Reason: GO:0070681 is obsolete and has consider advice rather than an automatic replacement. GatCAB modifies the amino acid on already charged tRNA; use GO:0019988 while retaining the supported organellar Gln-tRNA transamidation contribution in the molecular function. UniProt describes transamidation of misacylated Glu-tRNA(Gln) to correctly charged Gln-tRNA(Gln); in plant organelles this indirect (transamidation) route is the established mechanism for producing Gln-tRNA(Gln). Proposed replacements: charged-tRNA amino acid modification Supporting Evidence: file:POPTR/GATC/GATC-uniprot.txt Allows the formation of correctly charged Gln-tRNA(Gln) through the transamidation of misacylated Glu-tRNA(Gln) in chloroplasts and mitochondria. file:POPTR/GATC/GATC-deep-research-falcon.md It ensures availability of correctly charged **Gln‑tRNA\*Gln\*** in organelles that may not have an organellar GlnRS, by correcting ND‑GluRS misacylation via transamidation |
| GO:0005739 mitochondrion | IEA GO_REF:0000120 | ACCEPT | Summary: mitochondrion localization is supported for organellar GatC. Reason: UniProt places GatC in both mitochondrion and chloroplast, consistent with experimentally demonstrated dual targeting of plant GatCAB subunits to both organelles. Supporting Evidence: file:POPTR/GATC/GATC-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion file:POPTR/GATC/GATC-deep-research-falcon.md GatA, GatB, and GatC** are imported into **both mitochondria and chloroplasts** and processed to mature, protease-protected forms |
| GO:0006450 regulation of translational fidelity | IEA GO_REF:0000002 | KEEP AS NON CORE | Summary: Regulation of translational fidelity is related to correct tRNA charging but is broader than the direct GatC role. Reason: Retain as non-core while using glutaminyl-tRNAGln biosynthesis via transamidation as the direct process; by correcting ND-GluRS misacylation, GatCAB does contribute to faithful organellar translation. Supporting Evidence: file:POPTR/GATC/GATC-uniprot.txt Allows the formation of correctly charged Gln-tRNA(Gln) through the transamidation of misacylated Glu-tRNA(Gln) in chloroplasts and mitochondria. file:POPTR/GATC/GATC-deep-research-falcon.md It ensures availability of correctly charged **Gln‑tRNA\*Gln\*** in organelles that may not have an organellar GlnRS, by correcting ND‑GluRS misacylation via transamidation |
| GO:0009507 chloroplast | IEA GO_REF:0000120 | ACCEPT | Summary: chloroplast localization is supported for organellar GatC. Reason: UniProt places GatC in both mitochondrion and chloroplast; in Arabidopsis, GatA/B/C are imported into both mitochondria and chloroplasts, supporting plastid localization of the Populus ortholog. Supporting Evidence: file:POPTR/GATC/GATC-uniprot.txt Plastid, chloroplast file:POPTR/GATC/GATC-deep-research-falcon.md GatA, GatB, and GatC** are imported into **both mitochondria and chloroplasts** and processed to mature, protease-protected forms |
| GO:0016884 carbon-nitrogen ligase activity, with glutamine as amido-N-donor | IEA GO_REF:0000104 | MODIFY | Summary: Carbon-nitrogen ligase activity with glutamine as amido-N-donor is correct but less specific than the GatCAB reaction term. Reason: This generic parent term should be replaced by the specific GatCAB reaction term, glutaminyl-tRNA synthase (glutamine-hydrolyzing) activity, which is the precise activity of the complex (and is separately annotated for this entry). Proposed replacements: glutaminyl-tRNA synthase (glutamine-hydrolyzing) activity Supporting Evidence: file:POPTR/GATC/GATC-uniprot.txt Reaction=L-glutamyl-tRNA(Gln) + L-glutamine + ATP + H2O = L-glutaminyl- |
| GO:0030956 glutamyl-tRNA(Gln) amidotransferase complex | IEA GO_REF:0000104 | ACCEPT | Summary: GatC is part of the glutamyl-tRNA(Gln) amidotransferase complex. Reason: The protein is a subunit of the heterotrimeric GatCAB amidotransferase complex; GatC is the small accessory subunit required for proper folding of GatA and GatA binding to GatB. Supporting Evidence: file:POPTR/GATC/GATC-uniprot.txt Subunit of the heterotrimeric GatCAB amidotransferase (AdT) complex, composed of A, B and C subunits. file:POPTR/GATC/GATC-deep-research-falcon.md GatC as required for **proper folding of GatA** and for GatA binding to GatB |
| GO:0032543 mitochondrial translation | IEA GO_REF:0000104 | KEEP AS NON CORE | Summary: Mitochondrial translation is a valid organellar process consequence of Gln-tRNA(Gln) formation but is not the most direct function. Reason: The direct function is tRNA-dependent glutamine formation by transamidation; supplying Gln-tRNA(Gln) to organellar ribosomes (mitochondrial translation) is downstream of that activity. Supporting Evidence: file:POPTR/GATC/GATC-uniprot.txt Allows the formation of correctly charged Gln-tRNA(Gln) through the transamidation of misacylated Glu-tRNA(Gln) in chloroplasts and mitochondria. file:POPTR/GATC/GATC-deep-research-falcon.md GatCAB sits in the **organellar translation supply chain**, upstream of ribosomal protein synthesis |
| GO:0050567 glutaminyl-tRNA synthase (glutamine-hydrolyzing) activity | IEA GO_REF:0000120 | ACCEPT | Summary: Glutaminyl-tRNA synthase (glutamine-hydrolyzing) activity is the correct molecular function for GatCAB with GatC as a subunit. Reason: The reaction converts Glu-tRNA(Gln), glutamine, and ATP to Gln-tRNA(Gln); the contributes_to qualifier is appropriate because GatC is the accessory subunit and the catalysis is performed by the assembled GatCAB complex. Supporting Evidence: file:POPTR/GATC/GATC-uniprot.txt Reaction=L-glutamyl-tRNA(Gln) + L-glutamine + ATP + H2O = L-glutaminyl- file:POPTR/GATC/GATC-deep-research-falcon.md **GatC** is a **small accessory subunit** |
| GO:0070681 glutaminyl-tRNAGln biosynthesis via transamidation | IEA GO_REF:0000104 | MODIFY | Summary: Retain the supported biology under the current process term; the source GO identifier is obsolete. Reason: GO:0070681 is obsolete and has consider advice rather than an automatic replacement. GatCAB modifies the amino acid on already charged tRNA; use GO:0019988 while retaining the supported organellar Gln-tRNA transamidation contribution in the molecular function. UniProt describes transamidation of misacylated Glu-tRNA(Gln) to correctly charged Gln-tRNA(Gln); this indirect two-step pathway (ND-GluRS then GatCAB) is the established route for organellar Gln-tRNA(Gln) in plants. Proposed replacements: charged-tRNA amino acid modification Supporting Evidence: file:POPTR/GATC/GATC-uniprot.txt Allows the formation of correctly charged Gln-tRNA(Gln) through the transamidation of misacylated Glu-tRNA(Gln) in chloroplasts and mitochondria. file:POPTR/GATC/GATC-deep-research-falcon.md Gln-tRNA\*Gln\* is produced by an **indirect two-step pathway** |
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Download this section (compressed HTML)Q: Is Populus GatC dual-targeting to chloroplasts and mitochondria experimentally confirmed by proteomics or fluorescent tagging?
Q: Does GatC abundance limit organellar translational fidelity under stress?
Experiment: Tag endogenous GatC and test co-localization with chloroplast and mitochondrial markers while measuring organellar tRNA charging.
Type: targeted functional assay
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Download this section (compressed HTML)GATC-uniprot.txt and GATC-goa.tsv.Migrated the authored core process from GO:0070681 to GO:0019988, and reconciled affected annotation decisions and proposed replacements. Original GOA identifiers, labels, evidence and row counts remain unchanged. The underlying reaction and supported molecular function are retained. Term status and migration metadata are documented in modules/bacterial_aminoacyl_trna_charging-analysis/ontology-review.md and the pinned GO source stanzas.
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