QRSL1 (glutaminyl-tRNA amidotransferase subunit QRSL1, mitochondrial) is the human GatA subunit of the heterotrimeric mitochondrial glutamyl-tRNA(Gln) amidotransferase GatCAB, formed with GATB and GATC. Mammalian mitochondria lack a glutaminyl-tRNA synthetase: EARS2 misacylates tRNA(Gln) with glutamate, and GatCAB transamidates Glu-tRNA(Gln) to Gln-tRNA(Gln) using glutamine and ATP. QRSL1 belongs to the amidase-signature family and, with a Ser-cisSer-Lys catalytic triad, hydrolyses glutamine and channels the ammonia to GATB, which activates and amidates the tRNA-bound glutamate. The complex is the only mitochondrial route to Gln-tRNA(Gln) and is required for mitochondrial protein synthesis. Biallelic QRSL1 variants cause combined oxidative phosphorylation deficiency 40 (COXPD40), a lethal infantile disorder with hypertrophic cardiomyopathy, lactic acidosis and multiple respiratory chain defects.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0003824 catalytic activity | IEA GO_REF:0000002 | MODIFY | Summary: Catalytic activity from InterPro2GO mapping of the amidase signature domain (IPR000120). Reason: True but uninformative. QRSL1 carries the amidase-signature catalytic triad (Lys76, Ser171, Ser195 acyl-ester intermediate) and, as GatA, hydrolyses the amide donor glutamine within GatCAB. The specific activity of this subunit is glutaminase activity; the overall amidotransferase activity of the complex is captured by the contributes_to GO:0050567 annotations. Proposed replacements: glutaminase activity Supporting Evidence: file:human/QRSL1/QRSL1-uniprot.txt /note="Acyl-ester intermediate" file:human/QRSL1/QRSL1-uniprot.txt This subunit probably catalyzes the hydrolysis of the amido donor Gln, releasing ammonia that is sequestered within a channel in the GatCAB complex and made available to subunit B for downstream aminolysis of Glu-tRNA(Gln) PMID:26741492 QRSL1 (hGatA) is a glutaminase that produces ammonia, which is then transferred to misacylated Glu-charged tRNAGln to synthesize Gln-tRNAGln, which interacts with PET112L (hGatB) and GATC (hGatC) to form a trimeric enzyme hGatCAB[23]. |
| GO:0004359 glutaminase activity | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: Glutaminase activity from the HAMAP rule / EC 3.5.1.2 mapping. Reason: QRSL1 catalyses the glutamine-hydrolysis half-reaction of GatCAB, so the term is not wrong. But the ammonia is sequestered in a channel and used by GATB to amidate Glu-tRNA(Gln), not released as a product; the physiologically meaningful activity is the complex-level glutaminyl-tRNA synthase (glutamine-hydrolyzing) activity. Kept as a non-core partial activity. Supporting Evidence: file:human/QRSL1/QRSL1-uniprot.txt This subunit probably catalyzes the hydrolysis of the amido donor Gln, releasing ammonia that is sequestered within a channel in the GatCAB complex and made available to subunit B for downstream aminolysis of Glu-tRNA(Gln) PMID:26741492 QRSL1 (hGatA) is a glutaminase that produces ammonia, which is then transferred to misacylated Glu-charged tRNAGln to synthesize Gln-tRNAGln, which interacts with PET112L (hGatB) and GATC (hGatC) to form a trimeric enzyme hGatCAB[23]. PMID:30283131 In the bacterial GatCAB complex, GatA and GatB possess the catalytic amidase and kinase functions, respectively, while GatC serves as a stabilizing linker between them16. |
| GO:0005515 protein binding | IPI PMID:19805282 Biogenesis of glutaminyl-mt tRNAGln in human mitochondria. | REMOVE | Summary: Protein binding with GATC (PMID:19805282). Reason: Protein binding is uninformative. The interaction with GATC reflects co-membership of the heterotrimeric GatCAB glutamyl-tRNA(Gln) amidotransferase, which is captured by the GO:0030956 complex annotations. Removal does not dispute the interaction. Supporting Evidence: file:human/QRSL1/QRSL1-uniprot.txt Subunit of the heterotrimeric GatCAB amidotransferase (AdT) complex, composed of A (QRSL1), B (GATB) and C (GATC) subunits. |
| GO:0005515 protein binding | IPI PMID:19805282 Biogenesis of glutaminyl-mt tRNAGln in human mitochondria. | REMOVE | Summary: Protein binding with GATB (PMID:19805282). Reason: Protein binding is uninformative. The interaction with GATB reflects co-membership of the heterotrimeric GatCAB glutamyl-tRNA(Gln) amidotransferase, which is captured by the GO:0030956 complex annotations. Removal does not dispute the interaction. Supporting Evidence: file:human/QRSL1/QRSL1-uniprot.txt Subunit of the heterotrimeric GatCAB amidotransferase (AdT) complex, composed of A (QRSL1), B (GATB) and C (GATC) subunits. |
| GO:0005515 protein binding | IPI PMID:28514442 Architecture of the human interactome defines protein commun... | REMOVE | Summary: Protein binding with GATC (PMID:28514442). Reason: Protein binding is uninformative. The interaction with GATC reflects co-membership of the heterotrimeric GatCAB glutamyl-tRNA(Gln) amidotransferase, which is captured by the GO:0030956 complex annotations. Removal does not dispute the interaction. Supporting Evidence: file:human/QRSL1/QRSL1-uniprot.txt Subunit of the heterotrimeric GatCAB amidotransferase (AdT) complex, composed of A (QRSL1), B (GATB) and C (GATC) subunits. |
| GO:0005515 protein binding | IPI PMID:28514442 Architecture of the human interactome defines protein commun... | REMOVE | Summary: Protein binding with GATB (PMID:28514442). Reason: Protein binding is uninformative. The interaction with GATB reflects co-membership of the heterotrimeric GatCAB glutamyl-tRNA(Gln) amidotransferase, which is captured by the GO:0030956 complex annotations. Removal does not dispute the interaction. Supporting Evidence: file:human/QRSL1/QRSL1-uniprot.txt Subunit of the heterotrimeric GatCAB amidotransferase (AdT) complex, composed of A (QRSL1), B (GATB) and C (GATC) subunits. |
| GO:0005515 protein binding | IPI PMID:33961781 Dual proteome-scale networks reveal cell-specific remodeling... | REMOVE | Summary: Protein binding with GATC (PMID:33961781). Reason: Protein binding is uninformative. The interaction with GATC reflects co-membership of the heterotrimeric GatCAB glutamyl-tRNA(Gln) amidotransferase, which is captured by the GO:0030956 complex annotations. Removal does not dispute the interaction. Supporting Evidence: file:human/QRSL1/QRSL1-uniprot.txt Subunit of the heterotrimeric GatCAB amidotransferase (AdT) complex, composed of A (QRSL1), B (GATB) and C (GATC) subunits. |
| GO:0005515 protein binding | IPI PMID:33961781 Dual proteome-scale networks reveal cell-specific remodeling... | REMOVE | Summary: Protein binding with GATB (PMID:33961781). Reason: Protein binding is uninformative. The interaction with GATB reflects co-membership of the heterotrimeric GatCAB glutamyl-tRNA(Gln) amidotransferase, which is captured by the GO:0030956 complex annotations. Removal does not dispute the interaction. Supporting Evidence: file:human/QRSL1/QRSL1-uniprot.txt Subunit of the heterotrimeric GatCAB amidotransferase (AdT) complex, composed of A (QRSL1), B (GATB) and C (GATC) subunits. |
| GO:0005515 protein binding | IPI PMID:40205054 Multimodal cell maps as a foundation for structural and func... | REMOVE | Summary: Protein binding with GATC (PMID:40205054). Reason: Protein binding is uninformative. The interaction with GATC reflects co-membership of the heterotrimeric GatCAB glutamyl-tRNA(Gln) amidotransferase, which is captured by the GO:0030956 complex annotations. Removal does not dispute the interaction. Supporting Evidence: file:human/QRSL1/QRSL1-uniprot.txt Subunit of the heterotrimeric GatCAB amidotransferase (AdT) complex, composed of A (QRSL1), B (GATB) and C (GATC) subunits. |
| GO:0005515 protein binding | IPI PMID:40205054 Multimodal cell maps as a foundation for structural and func... | REMOVE | Summary: Protein binding with GATB (PMID:40205054). Reason: Protein binding is uninformative. The interaction with GATB reflects co-membership of the heterotrimeric GatCAB glutamyl-tRNA(Gln) amidotransferase, which is captured by the GO:0030956 complex annotations. Removal does not dispute the interaction. Supporting Evidence: file:human/QRSL1/QRSL1-uniprot.txt Subunit of the heterotrimeric GatCAB amidotransferase (AdT) complex, composed of A (QRSL1), B (GATB) and C (GATC) subunits. |
| GO:0005739 mitochondrion | HTP PMID:34800366 Quantitative high-confidence human mitochondrial proteome an... | ACCEPT | Summary: Mitochondrion (HTP). Reason: QRSL1 is a nuclear-encoded mitochondrial protein; GatCAB charges the mitochondrially encoded tRNA(Gln) in mitochondria. Localization is supported by the human GatCAB characterisation, the mitochondrial proteome and the HAMAP/PANTHER family. Supporting Evidence: file:human/QRSL1/QRSL1-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion PMID:30283131 Therefore, mitochondria are exclusively dependent on the GatCAB complex for appropriate charging of mt-tRNAGln with glutamine. |
| GO:0005739 mitochondrion | IBA GO_REF:0000033 | ACCEPT | Summary: Mitochondrion (IBA). Reason: QRSL1 is a nuclear-encoded mitochondrial protein; GatCAB charges the mitochondrially encoded tRNA(Gln) in mitochondria. Localization is supported by the human GatCAB characterisation, the mitochondrial proteome and the HAMAP/PANTHER family. Supporting Evidence: file:human/QRSL1/QRSL1-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion PMID:30283131 Therefore, mitochondria are exclusively dependent on the GatCAB complex for appropriate charging of mt-tRNAGln with glutamine. |
| GO:0005739 mitochondrion | IDA PMID:19805282 Biogenesis of glutaminyl-mt tRNAGln in human mitochondria. | ACCEPT | Summary: Mitochondrion (IDA). Reason: QRSL1 is a nuclear-encoded mitochondrial protein; GatCAB charges the mitochondrially encoded tRNA(Gln) in mitochondria. Localization is supported by the human GatCAB characterisation, the mitochondrial proteome and the HAMAP/PANTHER family. Supporting Evidence: file:human/QRSL1/QRSL1-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion PMID:30283131 Therefore, mitochondria are exclusively dependent on the GatCAB complex for appropriate charging of mt-tRNAGln with glutamine. |
| GO:0005739 mitochondrion | IEA GO_REF:0000120 | ACCEPT | Summary: Mitochondrion (IEA). Reason: QRSL1 is a nuclear-encoded mitochondrial protein; GatCAB charges the mitochondrially encoded tRNA(Gln) in mitochondria. Localization is supported by the human GatCAB characterisation, the mitochondrial proteome and the HAMAP/PANTHER family. Supporting Evidence: file:human/QRSL1/QRSL1-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion PMID:30283131 Therefore, mitochondria are exclusively dependent on the GatCAB complex for appropriate charging of mt-tRNAGln with glutamine. |
| GO:0006412 translation | IEA GO_REF:0000002 | MODIFY | Summary: Translation from InterPro2GO mapping of the GatA family (IPR004412). Reason: Human QRSL1 acts only in mitochondria, so the generic translation term is refined to its descendant mitochondrial translation, which the gene already carries (IBA, IEA, IMP). As for those rows, the refined term is non-core context; GatCAB prepares the Gln-tRNA(Gln) that mitochondrial translation consumes and does not perform a translation step itself; the core process is GO:0019988 charged-tRNA amino acid modification. Proposed replacements: mitochondrial translation Supporting Evidence: PMID:30283131 Pulse labeling of mitochondrial proteins with [35S]-methionine in the presence of emetine, a cytoplasmic protein synthesis inhibitor, revealed a strong and generalized mtDNA-encoded protein synthesis defect after a 90-min pulse in P4B (GATC) and in P3A (QRSL1) patients’ fibroblasts PMID:30283131 Therefore, mitochondria are exclusively dependent on the GatCAB complex for appropriate charging of mt-tRNAGln with glutamine. |
| GO:0030956 glutamyl-tRNA(Gln) amidotransferase complex | IBA GO_REF:0000033 | ACCEPT | Summary: Glutamyl-tRNA(Gln) amidotransferase complex (IBA). Reason: Core complex membership. QRSL1 is the A subunit of the human GatCAB heterotrimer, identified and reconstituted with recombinant subunits, and patient variants in QRSL1 impair transamidation. Supporting Evidence: PMID:19805282 In addition, we have identified a human homolog of the Glu-tRNA(Gln) amidotransferase, the hGatCAB heterotrimer. PMID:30283131 This latter conversion is performed by GatCAB, the glutamyl-tRNAGln amidotransferase protein complex, that consists of three subunits: GatA encoded by QRSL1, GatB encoded by GATB, and GatC encoded by GATC5,6. file:human/QRSL1/QRSL1-uniprot.txt Subunit of the heterotrimeric GatCAB amidotransferase (AdT) complex, composed of A (QRSL1), B (GATB) and C (GATC) subunits. |
| GO:0030956 glutamyl-tRNA(Gln) amidotransferase complex | IDA PMID:19805282 Biogenesis of glutaminyl-mt tRNAGln in human mitochondria. | ACCEPT | Summary: Glutamyl-tRNA(Gln) amidotransferase complex (IDA). Reason: Core complex membership. QRSL1 is the A subunit of the human GatCAB heterotrimer, identified and reconstituted with recombinant subunits, and patient variants in QRSL1 impair transamidation. Supporting Evidence: PMID:19805282 In addition, we have identified a human homolog of the Glu-tRNA(Gln) amidotransferase, the hGatCAB heterotrimer. PMID:30283131 This latter conversion is performed by GatCAB, the glutamyl-tRNAGln amidotransferase protein complex, that consists of three subunits: GatA encoded by QRSL1, GatB encoded by GATB, and GatC encoded by GATC5,6. file:human/QRSL1/QRSL1-uniprot.txt Subunit of the heterotrimeric GatCAB amidotransferase (AdT) complex, composed of A (QRSL1), B (GATB) and C (GATC) subunits. |
| GO:0030956 glutamyl-tRNA(Gln) amidotransferase complex | IEA GO_REF:0000120 | ACCEPT | Summary: Glutamyl-tRNA(Gln) amidotransferase complex (IEA). Reason: Core complex membership. QRSL1 is the A subunit of the human GatCAB heterotrimer, identified and reconstituted with recombinant subunits, and patient variants in QRSL1 impair transamidation. Supporting Evidence: PMID:19805282 In addition, we have identified a human homolog of the Glu-tRNA(Gln) amidotransferase, the hGatCAB heterotrimer. PMID:30283131 This latter conversion is performed by GatCAB, the glutamyl-tRNAGln amidotransferase protein complex, that consists of three subunits: GatA encoded by QRSL1, GatB encoded by GATB, and GatC encoded by GATC5,6. file:human/QRSL1/QRSL1-uniprot.txt Subunit of the heterotrimeric GatCAB amidotransferase (AdT) complex, composed of A (QRSL1), B (GATB) and C (GATC) subunits. |
| GO:0030956 glutamyl-tRNA(Gln) amidotransferase complex | IPI PMID:19805282 Biogenesis of glutaminyl-mt tRNAGln in human mitochondria. | ACCEPT | Summary: Glutamyl-tRNA(Gln) amidotransferase complex (IPI). Reason: Core complex membership. QRSL1 is the A subunit of the human GatCAB heterotrimer, identified and reconstituted with recombinant subunits, and patient variants in QRSL1 impair transamidation. Supporting Evidence: PMID:19805282 In addition, we have identified a human homolog of the Glu-tRNA(Gln) amidotransferase, the hGatCAB heterotrimer. PMID:30283131 This latter conversion is performed by GatCAB, the glutamyl-tRNAGln amidotransferase protein complex, that consists of three subunits: GatA encoded by QRSL1, GatB encoded by GATB, and GatC encoded by GATC5,6. file:human/QRSL1/QRSL1-uniprot.txt Subunit of the heterotrimeric GatCAB amidotransferase (AdT) complex, composed of A (QRSL1), B (GATB) and C (GATC) subunits. |
| GO:0032543 mitochondrial translation | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: Mitochondrial translation (IBA). Reason: Kept as non-core context, not core. GatCAB transamidates Glu-tRNA(Gln) to Gln-tRNA(Gln), preparing the charged tRNA that mitochondrial translation consumes; it does not itself perform a step of translation on the mitoribosome. The knockdown and patient data show that GatCAB is necessary for mitochondrial protein synthesis, which is necessity evidence, not participation. The MTO1 review takes the same line for a tRNA-preparing enzyme. The core process for this subunit is GO:0019988 charged-tRNA amino acid modification. Supporting Evidence: PMID:19805282 When any of the hGatCAB subunits were inactivated by siRNA-mediated knock down in human cells, the Glu-charged form of tRNA(Gln) accumulated and defects in respiration could be observed. PMID:30283131 Pulse labeling of mitochondrial proteins with [35S]-methionine in the presence of emetine, a cytoplasmic protein synthesis inhibitor, revealed a strong and generalized mtDNA-encoded protein synthesis defect after a 90-min pulse in P4B (GATC) and in P3A (QRSL1) patients’ fibroblasts PMID:30283131 Therefore, mitochondria are exclusively dependent on the GatCAB complex for appropriate charging of mt-tRNAGln with glutamine. |
| GO:0032543 mitochondrial translation | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: Mitochondrial translation (IEA). Reason: Kept as non-core context, not core. GatCAB transamidates Glu-tRNA(Gln) to Gln-tRNA(Gln), preparing the charged tRNA that mitochondrial translation consumes; it does not itself perform a step of translation on the mitoribosome. The knockdown and patient data show that GatCAB is necessary for mitochondrial protein synthesis, which is necessity evidence, not participation. The MTO1 review takes the same line for a tRNA-preparing enzyme. The core process for this subunit is GO:0019988 charged-tRNA amino acid modification. Supporting Evidence: PMID:19805282 When any of the hGatCAB subunits were inactivated by siRNA-mediated knock down in human cells, the Glu-charged form of tRNA(Gln) accumulated and defects in respiration could be observed. PMID:30283131 Pulse labeling of mitochondrial proteins with [35S]-methionine in the presence of emetine, a cytoplasmic protein synthesis inhibitor, revealed a strong and generalized mtDNA-encoded protein synthesis defect after a 90-min pulse in P4B (GATC) and in P3A (QRSL1) patients’ fibroblasts PMID:30283131 Therefore, mitochondria are exclusively dependent on the GatCAB complex for appropriate charging of mt-tRNAGln with glutamine. |
| GO:0032543 mitochondrial translation | IMP PMID:19805282 Biogenesis of glutaminyl-mt tRNAGln in human mitochondria. | KEEP AS NON CORE | Summary: Mitochondrial translation (IMP). Reason: Kept as non-core context, not core. GatCAB transamidates Glu-tRNA(Gln) to Gln-tRNA(Gln), preparing the charged tRNA that mitochondrial translation consumes; it does not itself perform a step of translation on the mitoribosome. The knockdown and patient data show that GatCAB is necessary for mitochondrial protein synthesis, which is necessity evidence, not participation. The MTO1 review takes the same line for a tRNA-preparing enzyme. The core process for this subunit is GO:0019988 charged-tRNA amino acid modification. Supporting Evidence: PMID:19805282 When any of the hGatCAB subunits were inactivated by siRNA-mediated knock down in human cells, the Glu-charged form of tRNA(Gln) accumulated and defects in respiration could be observed. PMID:30283131 Pulse labeling of mitochondrial proteins with [35S]-methionine in the presence of emetine, a cytoplasmic protein synthesis inhibitor, revealed a strong and generalized mtDNA-encoded protein synthesis defect after a 90-min pulse in P4B (GATC) and in P3A (QRSL1) patients’ fibroblasts PMID:30283131 Therefore, mitochondria are exclusively dependent on the GatCAB complex for appropriate charging of mt-tRNAGln with glutamine. |
| GO:0050567 glutaminyl-tRNA synthase (glutamine-hydrolyzing) activity | IBA GO_REF:0000033 | ACCEPT | Summary: Contributes to glutaminyl-tRNA synthase (glutamine-hydrolyzing) activity (IBA). Reason: Core activity. Recombinant human GatCAB (QRSL1, GATB, GATC) converts Glu-tRNA(Gln) to Gln-tRNA(Gln) in vitro, QRSL1 supplies the glutaminase site, and QRSL1 patient variants cause severe transamidation defects. contributes_to correctly reflects that the activity is that of the complex. Supporting Evidence: PMID:19805282 We successfully reconstituted in vitro Gln-tRNA(Gln) formation catalyzed by the recombinant mtGluRS and hGatCAB. PMID:26741492 We clearly showed that mutations in QRSL1 (GatA), a component of hGatCAB, observed in our patients were associated with severe transamidation activity defects. file:human/QRSL1/QRSL1-uniprot.txt This subunit probably catalyzes the hydrolysis of the amido donor Gln, releasing ammonia that is sequestered within a channel in the GatCAB complex and made available to subunit B for downstream aminolysis of Glu-tRNA(Gln) |
| GO:0050567 glutaminyl-tRNA synthase (glutamine-hydrolyzing) activity | IDA PMID:19805282 Biogenesis of glutaminyl-mt tRNAGln in human mitochondria. | ACCEPT | Summary: Contributes to glutaminyl-tRNA synthase (glutamine-hydrolyzing) activity (IDA). Reason: Core activity. Recombinant human GatCAB (QRSL1, GATB, GATC) converts Glu-tRNA(Gln) to Gln-tRNA(Gln) in vitro, QRSL1 supplies the glutaminase site, and QRSL1 patient variants cause severe transamidation defects. contributes_to correctly reflects that the activity is that of the complex. Supporting Evidence: PMID:19805282 We successfully reconstituted in vitro Gln-tRNA(Gln) formation catalyzed by the recombinant mtGluRS and hGatCAB. PMID:26741492 We clearly showed that mutations in QRSL1 (GatA), a component of hGatCAB, observed in our patients were associated with severe transamidation activity defects. file:human/QRSL1/QRSL1-uniprot.txt This subunit probably catalyzes the hydrolysis of the amido donor Gln, releasing ammonia that is sequestered within a channel in the GatCAB complex and made available to subunit B for downstream aminolysis of Glu-tRNA(Gln) |
| GO:0050567 glutaminyl-tRNA synthase (glutamine-hydrolyzing) activity | IEA GO_REF:0000002 | ACCEPT | Summary: Glutaminyl-tRNA synthase (glutamine-hydrolyzing) activity from InterPro2GO mapping of the GatA family (IPR004412). Reason: Correct core activity. The activity belongs to the GatCAB heterotrimer, to which QRSL1 contributes the glutaminase site, so it is more precisely expressed with the contributes_to qualifier used in the IBA and IDA rows for this gene. Supporting Evidence: file:human/QRSL1/QRSL1-uniprot.txt This subunit probably catalyzes the hydrolysis of the amido donor Gln, releasing ammonia that is sequestered within a channel in the GatCAB complex and made available to subunit B for downstream aminolysis of Glu-tRNA(Gln) PMID:26741492 We clearly showed that mutations in QRSL1 (GatA), a component of hGatCAB, observed in our patients were associated with severe transamidation activity defects. |
| GO:0070681 obsolete glutaminyl-tRNAGln biosynthesis via transamidation | IBA GO_REF:0000033 | MODIFY | Summary: Obsolete term glutaminyl-tRNAGln biosynthesis via transamidation (IBA). Reason: The biology is correct (GatCAB converts Glu-tRNA(Gln) to Gln-tRNA(Gln)), but GO:0070681 is obsolete as a pathway-variant term and GO says such annotations need review rather than automatic migration. Because GatCAB amidates glutamate already attached to tRNA(Gln), the process is captured by charged-tRNA amino acid modification, consistent with the GATC review; the activity is captured by GO:0050567. Propagation Review Root cause: NO FAILURE CORE Sources checked: PANTHER:PTN000224178 SUPPORTS TRANSFER The GatA-family node correctly carries the transamidation function to human QRSL1; only the term has since been obsoleted, so the row is re-expressed with GO:0019988 rather than rejected. Proposed replacements: charged-tRNA amino acid modification Supporting Evidence: PMID:19805282 We successfully reconstituted in vitro Gln-tRNA(Gln) formation catalyzed by the recombinant mtGluRS and hGatCAB. PMID:30283131 mt-tRNAGln is indirectly charged by a transamidation reaction involving the GatCAB aminoacyl-tRNA amidotransferase complex. |
| GO:0070681 obsolete glutaminyl-tRNAGln biosynthesis via transamidation | IDA PMID:19805282 Biogenesis of glutaminyl-mt tRNAGln in human mitochondria. | MODIFY | Summary: Obsolete term glutaminyl-tRNAGln biosynthesis via transamidation (IDA). Reason: The biology is correct (GatCAB converts Glu-tRNA(Gln) to Gln-tRNA(Gln)), but GO:0070681 is obsolete as a pathway-variant term and GO says such annotations need review rather than automatic migration. Because GatCAB amidates glutamate already attached to tRNA(Gln), the process is captured by charged-tRNA amino acid modification, consistent with the GATC review; the activity is captured by GO:0050567. Proposed replacements: charged-tRNA amino acid modification Supporting Evidence: PMID:19805282 We successfully reconstituted in vitro Gln-tRNA(Gln) formation catalyzed by the recombinant mtGluRS and hGatCAB. PMID:30283131 mt-tRNAGln is indirectly charged by a transamidation reaction involving the GatCAB aminoacyl-tRNA amidotransferase complex. |
| GO:0070681 obsolete glutaminyl-tRNAGln biosynthesis via transamidation | IEA GO_REF:0000104 | MODIFY | Summary: Obsolete term glutaminyl-tRNAGln biosynthesis via transamidation (IEA). Reason: The biology is correct (GatCAB converts Glu-tRNA(Gln) to Gln-tRNA(Gln)), but GO:0070681 is obsolete as a pathway-variant term and GO says such annotations need review rather than automatic migration. Because GatCAB amidates glutamate already attached to tRNA(Gln), the process is captured by charged-tRNA amino acid modification, consistent with the GATC review; the activity is captured by GO:0050567. Proposed replacements: charged-tRNA amino acid modification Supporting Evidence: PMID:19805282 We successfully reconstituted in vitro Gln-tRNA(Gln) formation catalyzed by the recombinant mtGluRS and hGatCAB. PMID:30283131 mt-tRNAGln is indirectly charged by a transamidation reaction involving the GatCAB aminoacyl-tRNA amidotransferase complex. |
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Download this section (compressed HTML)Q: Does human QRSL1 hydrolyse glutamine only when GatCAB is bound to Glu-tRNA(Gln), as in bacterial GatCAB, so that the glutaminase activity is strictly coupled to transamidation?
Q: Why do QRSL1-deficient fibroblasts show near-normal tRNA(Gln) charging in high glutamine while heart is severely affected; is local glutamine availability in cardiomyocytes limiting for a partially active GatCAB?
Experiment: Measure glutaminase and transamidation kinetics of purified recombinant human GatCAB carrying QRSL1 patient variants (for example Gly133 and Thr196 region substitutions) with and without Glu-tRNA(Gln), to test coupling and define the residual activity of each allele.
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