AARS1

UniProt ID: P49588
Organism: Homo sapiens
Review Status: DRAFT
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Gene Description

AARS1 is a predominantly cytosolic class II alanyl-tRNA synthetase that activates L-alanine with ATP and transfers it to cytosolic tRNA(Ala). Its editing domain hydrolyzes incorrectly charged Ser-tRNA(Ala), while the C-terminal C-Ala region helps coordinate tRNA recognition, aminoacylation, and post-transfer editing to preserve translational fidelity. Under high intracellular L-lactate, AARS1 can also generate lactoyl-AMP and transfer lactyl groups to protein lysines. Lactate-dependent nuclear import enables context-specific lactylation of YAP1, TEAD1, and TP53, increasing YAP-TEAD transcriptional output and suppressing p53 signaling in tumor models. AARS1 depletion did not reduce basal global lysine lactylation in untreated HEK293T cells. Pathogenic AARS1 variants cause recessive neurodevelopmental syndromes, nonphotosensitive trichothiodystrophy, and dominant axonal neuropathy. Variant effects include impaired protein stability, charging, or editing, altered charging kinetics, and dominant-negative interference with wild-type AARS1. Purified recombinant human AARS1 was reported to behave as a monomer. Humanized-yeast co-expression experiments show mutant interference with wild-type AARS1, interpreted in a homodimer model; these heterologous assays do not establish the predominant oligomeric state in human cells.

Proposed New Ontology Terms

peptidyl-lysine lactylation

Definition: A peptidyl-lysine modification process in which a lactyl group is covalently added to the epsilon-amino group of a lysine residue within a protein.

Justification: GO:0141207 captures the ATP-dependent molecular activity but no current biological process term captures its immediate protein-modification outcome. The proposed term should be placed under GO:0018205 peptidyl-lysine modification and related to the broader GO:0043543 protein acylation branch; it would support curation of AARS1 and other experimentally established lysine lactylation mechanisms without conflating them with downstream signaling phenotypes.

Parent term: peptidyl-lysine modification

Supporting Evidence:

Existing Annotations Review

GO Term Evidence Action Reason
GO:0005829 cytosol
IBA
GO_REF:0000033
ACCEPT
Summary: IBA cytosol assignment, consistent with AARS1's identity as the cytoplasmic AlaRS and with independent HPA and experimental cytoplasmic localization.
Reason: The cytosol is the primary compartment for the core tRNA-charging and editing functions.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
PANTHER:PTN002622950 SUPPORTS TRANSFER
The PAINT ancestral node places cytosolic localization in the AARS1 lineage. Human localization evidence corroborates this inherited function; the target in WITH/FROM is experimental grounding, not circularity.
GO:0004813 alanine-tRNA ligase activity
IBA
GO_REF:0000033
ACCEPT
Summary: IBA assignment of substrate-specific alanine-tRNA ligase activity, corroborated by multiple human biochemical studies.
Reason: This is AARS1's principal conserved molecular function.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
PANTHER:PTN000206950 SUPPORTS TRANSFER
The ancestral alanine-tRNA ligase assertion is consistent with the conserved AlaRS catalytic reaction and direct human aminoacylation assays (PMID:28493438). No target-specific loss is evident.
Supporting Evidence:
PMID:28493438
The aminoacylation activities of both variants were then tested using 14C-labeled alanine with various concentrations of tRNA.
GO:0002161 aminoacyl-tRNA deacylase activity
IBA
GO_REF:0000033
ACCEPT
Summary: IBA assignment of the editing-domain deacylase activity; human AARS1 editing was directly measured with Ser-tRNA(Ala).
Reason: Post-transfer editing is a conserved core function and is directly verified in the human target.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
PANTHER:PTN000206950 SUPPORTS TRANSFER
The ancestral editing assertion is corroborated by direct human Ser-tRNA(Ala) deacylation assays (PMID:28493438); the target appearing among extant evidence is expected.
Supporting Evidence:
PMID:28493438
AARS possesses an editing domain that is capable of hydrolyzing the mischarged tRNAAla
GO:0006419 alanyl-tRNA aminoacylation
IBA
GO_REF:0000033
ACCEPT
Summary: IBA assignment of the process producing Ala-tRNA(Ala), supported by human enzymology and cross-species complementation.
Reason: Alanyl-tRNA aminoacylation is the central conserved process executed by AARS1.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
PANTHER:PTN000206950 SUPPORTS TRANSFER
The ancestral aminoacylation assertion is supported by human tRNA charging and complementation data. This is a clade-level inheritance claim, not a donor-count or pairwise-similarity assessment.
GO:0000166 nucleotide binding
IEA
GO_REF:0000002
MODIFY
Summary: InterPro inference of generic nucleotide binding from AlaRS catalytic/editing domains; the relevant nucleotide substrate is ATP.
Reason: The parent binding term is true but too broad; ATP binding is the mechanistically relevant specificity.
Propagation Review
Root cause: TERM SCOPING PROBLEM
Failure modes: GRANULARITY MISMATCH
Sources checked:
InterPro:IPR002318 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for nucleotide binding. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
InterPro:IPR018162 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for nucleotide binding. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
InterPro:IPR018163 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for nucleotide binding. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
InterPro:IPR018164 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for nucleotide binding. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
Proposed replacements: ATP binding
GO:0003676 nucleic acid binding
IEA
GO_REF:0000002
MODIFY
Summary: InterPro inference of generic nucleic-acid binding; the core physiological nucleic-acid ligand is tRNA.
Reason: Use informative tRNA binding. Isolated C-Ala can bind DNA in vitro, but that does not justify generic nucleic-acid binding as the core annotation.
Propagation Review
Root cause: TERM SCOPING PROBLEM
Failure modes: GRANULARITY MISMATCH
Sources checked:
InterPro:IPR003156 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for nucleic acid binding. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
InterPro:IPR018165 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for nucleic acid binding. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
Proposed replacements: tRNA binding
GO:0004812 aminoacyl-tRNA ligase activity
IEA
GO_REF:0000002
MODIFY
Summary: InterPro inference of broad aminoacyl-tRNA ligase activity from the class-II synthetase fold.
Reason: The activity is correct but too general for a protein with established alanine specificity.
Propagation Review
Root cause: TERM SCOPING PROBLEM
Failure modes: GRANULARITY MISMATCH
Sources checked:
InterPro:IPR012947 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for aminoacyl-tRNA ligase activity. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
Proposed replacements: alanine-tRNA ligase activity
GO:0004813 alanine-tRNA ligase activity
IEA
GO_REF:0000120
ACCEPT
Summary: Convergent ARBA, UniRule, InterPro, EC 6.1.1.7 and RHEA:12540 assignment of alanine-tRNA ligase activity.
Reason: The electronic mapping exactly matches the directly characterized core reaction.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
ARBA:ARBA00087807 UNRESOLVED
This rule is named in the GOA seed for alanine-tRNA ligase activity. Rule conditions were not independently re-audited; acceptance is supported by the reviewed UniProt record and human biochemical evidence rather than an assertion that the complete rule is validated.
UniProtKB:P50475 SUPPORTS TRANSFER
Rat Aars1 is the orthologous donor. QuickGO retains tRNA- and alanine-binding evidence from PMID:2040280; human charging and RNA-recognition data independently support the transferred substrate-recognition function.
ensembl:ENSRNOP00000025051 UNRESOLVED
Secondary Ensembl protein identifier supplied alongside the rodent UniProt donor in GOA. The independent Ensembl record was not re-resolved; the accompanying UniProt and direct human evidence support the biological assessment.
UniProtKB:Q8BGQ7 SUPPORTS TRANSFER
Mouse Aars is the orthologous donor. QuickGO retains experimental editing/fidelity evidence; human AARS1 charging and Ser-tRNA(Ala) editing independently corroborate the relevant conserved function (PMID:28493438).
ensembl:ENSMUSP00000034441 UNRESOLVED
Secondary Ensembl protein identifier supplied alongside the rodent UniProt donor in GOA. The independent Ensembl record was not re-resolved; the accompanying UniProt and direct human evidence support the biological assessment.
InterPro:IPR018162 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for alanine-tRNA ligase activity. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
InterPro:IPR018164 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for alanine-tRNA ligase activity. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
InterPro:IPR018165 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for alanine-tRNA ligase activity. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
InterPro:IPR023033 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for alanine-tRNA ligase activity. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
RHEA:12540 SUPPORTS TRANSFER
This reaction identifier encodes ATP-dependent ligation of alanine to tRNA(Ala), matching the directly demonstrated canonical human AARS1 reaction. It does not encode peptide lactylation.
EC:6.1.1.7 SUPPORTS TRANSFER
This reaction identifier encodes ATP-dependent ligation of alanine to tRNA(Ala), matching the directly demonstrated canonical human AARS1 reaction. It does not encode peptide lactylation.
UniRule:UR000375824 UNRESOLVED
This rule is named in the GOA seed for alanine-tRNA ligase activity. Rule conditions were not independently re-audited; acceptance is supported by the reviewed UniProt record and human biochemical evidence rather than an assertion that the complete rule is validated.
GO:0005524 ATP binding
IEA
GO_REF:0000120
ACCEPT
Summary: Electronic ATP-binding assignment from conserved AlaRS catalytic domains and UniRule.
Reason: ATP binding is obligatory for adenylate-intermediate formation in AARS1 catalysis.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
UniProtKB:P50475 SUPPORTS TRANSFER
Rat Aars1 is the orthologous donor. QuickGO retains tRNA- and alanine-binding evidence from PMID:2040280; human charging and RNA-recognition data independently support the transferred substrate-recognition function.
ensembl:ENSRNOP00000025051 UNRESOLVED
Secondary Ensembl protein identifier supplied alongside the rodent UniProt donor in GOA. The independent Ensembl record was not re-resolved; the accompanying UniProt and direct human evidence support the biological assessment.
InterPro:IPR012947 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for ATP binding. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
InterPro:IPR018162 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for ATP binding. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
InterPro:IPR018164 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for ATP binding. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
InterPro:IPR018165 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for ATP binding. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
UniRule:UR000375824 UNRESOLVED
This rule is named in the GOA seed for ATP binding. Rule conditions were not independently re-audited; acceptance is supported by the reviewed UniProt record and human biochemical evidence rather than an assertion that the complete rule is validated.
GO:0005634 nucleus
IEA
GO_REF:0000044
ACCEPT
Summary: Electronic nuclear localization mapped from reviewed UniProt localization and corroborated by lactate-induced, KPNA4-dependent nuclear entry in human cells.
Reason: The nucleus is a bona fide elevated-lactate conditional execution site for AARS1 protein lactyltransferase activity. Acceptance does not imply that AARS1 is constitutively nuclear or that the nucleus replaces its primary cytoplasmic localization.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
UniProtKB-SubCell:SL-0191 SUPPORTS TRANSFER
Reviewed UniProt localization term supplies this mapping. Independent human-cell localization data in PMID:38512451 corroborate it; nuclear localization is lactate responsive.
GO:0005737 cytoplasm
IEA
GO_REF:0000120
ACCEPT
Summary: Electronic cytoplasmic localization inferred from AlaRS domains and reviewed UniProt localization.
Reason: The cytoplasm is the primary setting for AARS1 tRNA charging/editing and is independently observed in human cells.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
InterPro:IPR002318 UNRESOLVED
This signature is present in the combined electronic source field, but a catalytic-family/domain match alone does not establish cytoplasmic localization. The separate SL-0086 localization mapping and human localization evidence support the accepted annotation; this signature-specific location inference was not independently resolved.
InterPro:IPR018162 UNRESOLVED
This signature is present in the combined electronic source field, but a catalytic-family/domain match alone does not establish cytoplasmic localization. The separate SL-0086 localization mapping and human localization evidence support the accepted annotation; this signature-specific location inference was not independently resolved.
UniProtKB-SubCell:SL-0086 SUPPORTS TRANSFER
The reviewed UniProt cytoplasmic-location vocabulary supplies the direct location mapping. It agrees with the canonical cytosolic tRNA-charging role and human localization data; conditional nuclear redistribution does not contradict this location.
GO:0006419 alanyl-tRNA aminoacylation
IEA
GO_REF:0000120
ACCEPT
Summary: Electronic assignment of alanyl-tRNA aminoacylation from convergent family, orthology and domain evidence.
Reason: This is AARS1's core process and is directly established by human enzymology and loss-of-function studies.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
ARBA:ARBA00085735 UNRESOLVED
This rule is named in the GOA seed for alanyl-tRNA aminoacylation. Rule conditions were not independently re-audited; acceptance is supported by the reviewed UniProt record and human biochemical evidence rather than an assertion that the complete rule is validated.
UniProtKB:P50475 SUPPORTS TRANSFER
Rat Aars1 is the orthologous donor. QuickGO retains tRNA- and alanine-binding evidence from PMID:2040280; human charging and RNA-recognition data independently support the transferred substrate-recognition function.
ensembl:ENSRNOP00000025051 UNRESOLVED
Secondary Ensembl protein identifier supplied alongside the rodent UniProt donor in GOA. The independent Ensembl record was not re-resolved; the accompanying UniProt and direct human evidence support the biological assessment.
UniProtKB:Q8BGQ7 SUPPORTS TRANSFER
Mouse Aars is the orthologous donor. QuickGO retains experimental editing/fidelity evidence; human AARS1 charging and Ser-tRNA(Ala) editing independently corroborate the relevant conserved function (PMID:28493438).
ensembl:ENSMUSP00000034441 UNRESOLVED
Secondary Ensembl protein identifier supplied alongside the rodent UniProt donor in GOA. The independent Ensembl record was not re-resolved; the accompanying UniProt and direct human evidence support the biological assessment.
InterPro:IPR018162 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for alanyl-tRNA aminoacylation. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
InterPro:IPR018164 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for alanyl-tRNA aminoacylation. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
InterPro:IPR018165 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for alanyl-tRNA aminoacylation. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
GO:0008270 zinc ion binding
IEA
GO_REF:0000104
ACCEPT
Summary: UniRule transfer of zinc-ion binding; the reviewed AARS1 record specifies one zinc ion per subunit.
Reason: Zinc binding is a conserved component of AlaRS architecture with no evidence of target-specific loss.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
UniRule:UR000375824 UNRESOLVED
This rule is named in the GOA seed for zinc ion binding. Rule conditions were not independently re-audited; acceptance is supported by the reviewed UniProt record and human biochemical evidence rather than an assertion that the complete rule is validated.
GO:0043039 tRNA aminoacylation
IEA
GO_REF:0000002
MODIFY
Summary: InterPro inference of broad tRNA aminoacylation from the tRNA-synthetase additional domain.
Reason: Use the alanine-specific child process established for AARS1.
Propagation Review
Root cause: TERM SCOPING PROBLEM
Failure modes: GRANULARITY MISMATCH
Sources checked:
InterPro:IPR012947 SUPPORTS TRANSFER
This InterPro signature is a proximate electronic source for tRNA aminoacylation. The inference is consistent with the AlaRS catalytic/RNA-recognition architecture; direct human evidence determines the specificity recommended in review.reason.
Proposed replacements: alanyl-tRNA aminoacylation
GO:0106074 aminoacyl-tRNA metabolism involved in translational fidelity
IEA
GO_REF:0000120
ACCEPT
Summary: Electronic inference of aminoacyl-tRNA quality-control metabolism from AARS1's deacylase activities.
Reason: The term accurately captures editing that removes incorrect amino acids from charged tRNA.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
GO:0002161 SUPPORTS TRANSFER
The source deacylase activity removes an incorrect amino acid from charged tRNA, directly satisfying the destination translational-fidelity process. Human editing is verified in PMID:28493438.
GO:0002196 SUPPORTS TRANSFER
The source deacylase activity removes an incorrect amino acid from charged tRNA, directly satisfying the destination translational-fidelity process. Human editing is verified in PMID:28493438.
GO:0141207 peptide lactyltransferase (ATP-dependent) activity
IEA
GO_REF:0000120
ACCEPT
Summary: Electronic assignment of ATP-dependent peptide lactyltransferase activity from the exact Rhea reactions, corroborated by 2024 studies and 2026 structural/biochemical work.
Reason: This is a real intrinsic AARS1 activity under elevated-lactate and substrate-specific conditions; in PMID:40835008, AARS1 depletion did not reduce basal global Kla in untreated HEK293T cells.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
ARBA:ARBA00085408 UNRESOLVED
This rule is named in the GOA seed for peptide lactyltransferase (ATP-dependent) activity. Rule conditions were not independently re-audited; acceptance is supported by the reviewed UniProt record and human biochemical evidence rather than an assertion that the complete rule is validated.
RHEA:80271 SUPPORTS TRANSFER
This reaction identifier supplies the electronic peptide lactyltransferase (ATP-dependent) activity mapping. The reaction matches direct human enzymology; for lactylation the accepted scope remains conditional and substrate dependent.
RHEA:80275 SUPPORTS TRANSFER
This reaction identifier supplies the electronic peptide lactyltransferase (ATP-dependent) activity mapping. The reaction matches direct human enzymology; for lactylation the accepted scope remains conditional and substrate dependent.
Supporting Evidence:
PMID:38512451
AARS1 was able to directly lactylate histone H3 and H4 in a manner dependent on both lactate and ATP
PMID:40835008
However, the knockdown of either enzyme did not alter Kla levels
GO:0000049 tRNA binding
IEA
GO_REF:0000107
ACCEPT
Summary: Ensembl orthology transfer of tRNA binding from rat AARS1, concordant with human tRNA/microhelix recognition experiments.
Reason: tRNA binding is essential to aminoacylation/editing and is conserved in cytoplasmic AlaRS.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
UniProtKB:P50475 SUPPORTS TRANSFER
Rat Aars1 is the orthologous donor. QuickGO retains tRNA- and alanine-binding evidence from PMID:2040280; human charging and RNA-recognition data independently support the transferred substrate-recognition function.
ensembl:ENSRNOP00000025051 UNRESOLVED
Secondary Ensembl protein identifier supplied alongside the rodent UniProt donor in GOA. The independent Ensembl record was not re-resolved; the accompanying UniProt and direct human evidence support the biological assessment.
GO:0002161 aminoacyl-tRNA deacylase activity
IEA
GO_REF:0000107
ACCEPT
Summary: Ensembl transfer of aminoacyl-tRNA deacylase activity from mouse Aars, independently verified by human editing assays.
Reason: The editing domain and activity are conserved and directly present in the human target.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
UniProtKB:Q8BGQ7 SUPPORTS TRANSFER
Mouse Aars is the orthologous donor. QuickGO retains experimental editing/fidelity evidence; human AARS1 charging and Ser-tRNA(Ala) editing independently corroborate the relevant conserved function (PMID:28493438).
ensembl:ENSMUSP00000034441 UNRESOLVED
Secondary Ensembl protein identifier supplied alongside the rodent UniProt donor in GOA. The independent Ensembl record was not re-resolved; the accompanying UniProt and direct human evidence support the biological assessment.
GO:0002196 Ser-tRNA(Ala) deacylase activity
IEA
GO_REF:0000107
ACCEPT
Summary: Ensembl transfer of Ser-tRNA(Ala) deacylase activity from mouse Aars, independently measured for recombinant human AARS1.
Reason: Direct human evidence makes this substrate-specific orthology transfer safe.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
UniProtKB:Q8BGQ7 SUPPORTS TRANSFER
Mouse Aars is the orthologous donor. QuickGO retains experimental editing/fidelity evidence; human AARS1 charging and Ser-tRNA(Ala) editing independently corroborate the relevant conserved function (PMID:28493438).
ensembl:ENSMUSP00000034441 UNRESOLVED
Secondary Ensembl protein identifier supplied alongside the rodent UniProt donor in GOA. The independent Ensembl record was not re-resolved; the accompanying UniProt and direct human evidence support the biological assessment.
GO:0006400 tRNA modification
IEA
GO_REF:0000107
MODIFY
Summary: Ensembl transfer of tRNA modification from mouse Aars, apparently intended to represent editing of mischarged tRNA(Ala).
Reason: GO:0006400 requires covalent alteration of tRNA nucleotides; AARS1 instead hydrolyzes a mischarged amino acid. Use the explicit aminoacyl-tRNA fidelity process.
Propagation Review
Root cause: TERM SCOPING PROBLEM
Failure modes: ROLE CONFLATION
Sources checked:
UniProtKB:Q8BGQ7 SOURCE BAD
QuickGO retains mouse Aars tRNA-modification annotations from PMID:16906134, PMID:25422440 and PMID:29769718. Those studies concern editing of aminoacyl-tRNA, whereas GO:0006400 requires covalent alteration of tRNA nucleotides. The source term choice, not orthology, is the issue.
ensembl:ENSMUSP00000034441 UNRESOLVED
Ensembl mouse-protein identifier accompanies the Q8BGQ7 donor in the seed. Its independent record was not re-resolved; the traceable mouse UniProt source concerns aminoacyl-tRNA editing, not nucleotide modification.
GO:0016597 amino acid binding
IEA
GO_REF:0000107
ACCEPT
Summary: Ensembl transfer of generic amino-acid binding from rat AARS1; alanine is the characterized cognate substrate.
Reason: Alanine recognition is an obligatory part of the established alanine-tRNA ligase reaction. The broad binding term is true; lack of specificity alone does not make the orthology transfer an over-annotation. The catalytic annotation carries the more informative account of this function.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
UniProtKB:P50475 SUPPORTS TRANSFER
Rat Aars1 is the orthologous donor. QuickGO retains tRNA- and alanine-binding evidence from PMID:2040280; human charging and RNA-recognition data independently support the transferred substrate-recognition function.
ensembl:ENSRNOP00000025051 UNRESOLVED
Secondary Ensembl protein identifier supplied alongside the rodent UniProt donor in GOA. The independent Ensembl record was not re-resolved; the accompanying UniProt and direct human evidence support the biological assessment.
GO:0140018 regulation of cytoplasmic translational fidelity
IEA
GO_REF:0000107
MODIFY
Summary: Ensembl transfer of regulation of cytoplasmic translational fidelity from mouse Aars.
Reason: The existing term describes a valid downstream consequence of AARS1 proofreading, but the replacement more directly captures its aminoacyl-tRNA editing mechanism.
Propagation Review
Root cause: TERM SCOPING PROBLEM
Failure modes: GRANULARITY MISMATCH
Sources checked:
UniProtKB:Q8BGQ7 SUPPORTS TRANSFER
Mouse Aars is the orthologous donor. QuickGO retains experimental editing/fidelity evidence; human AARS1 charging and Ser-tRNA(Ala) editing independently corroborate the relevant conserved function (PMID:28493438).
ensembl:ENSMUSP00000034441 UNRESOLVED
Secondary Ensembl protein identifier supplied alongside the rodent UniProt donor in GOA. The independent Ensembl record was not re-resolved; the accompanying UniProt and direct human evidence support the biological assessment.
GO:0004813 alanine-tRNA ligase activity
TAS
Reactome:R-HSA-379864
ACCEPT
Summary: Reactome assigns alanine-tRNA ligase activity to AARS1 in the cytosolic Ala-tRNA(Ala) reaction.
Reason: The reaction and specificity exactly match the directly characterized core activity.
GO:0005829 cytosol
IDA
GO_REF:0000052
ACCEPT
Summary: HPA immunofluorescence places AARS1 in the cytosol.
Reason: Cytosolic localization is consistent with AARS1's core role as the cytoplasmic alanine-tRNA synthetase.
GO:0004813 alanine-tRNA ligase activity
EXP
PMID:25817015
Loss-of-function alanyl-tRNA synthetase mutations cause an a...
ACCEPT
Summary: Experimental annotation from human loss-of-function variants with reduced alanyl-tRNA charging.
Reason: The study supports the core catalytic activity; because the cache is abstract-only, the curator's full-text experimental assessment is retained.
Supporting Evidence:
PMID:25817015
demonstrating that defects of alanyl-tRNA charging can result in a wide spectrum of disease manifestations
GO:0004813 alanine-tRNA ligase activity
EXP
PMID:27911835
Two crystal structures reveal design for repurposing the C-A...
ACCEPT
Summary: Experimental alanine-tRNA ligase annotation associated with structural/biochemical analysis of human AlaRS.
Reason: The activity is established independently; the abstract-only cache gives no basis to overrule the curator.
GO:0005737 cytoplasm
EXP
PMID:27911835
Two crystal structures reveal design for repurposing the C-A...
ACCEPT
Summary: Experimental cytoplasmic localization associated with the human AlaRS structural study.
Reason: The assignment agrees with HPA, Reactome, UniProt and lactate-response localization data; retain the curator's full-text assessment.
GO:0141207 peptide lactyltransferase (ATP-dependent) activity
IDA
PMID:39322678
AARS1 and AARS2 sense L-lactate to regulate cGAS as global l...
ACCEPT
Summary: Direct ATP-dependent peptide lactyltransferase annotation; AARS1/AARS2 act as intracellular lactate sensors and directly catalyze lysine lactylation.
Reason: Primary studies support the activity, qualified to elevated-lactate and substrate-specific contexts rather than dominant basal global lactylation.
Supporting Evidence:
PMID:39322678
they directly catalyse L-lactate for ATP-dependent lactylation on the lysine acceptor end
GO:0005634 nucleus
IDA
PMID:38512451
The alanyl-tRNA synthetase AARS1 moonlights as a lactyltrans...
ACCEPT
Summary: Direct nuclear localization in gastric-cancer cells under elevated lactate, where AARS1 executes protein lactyltransferase activity on YAP and TEAD1.
Reason: The nucleus is a directly demonstrated elevated-lactate conditional execution site for the accepted lactyltransferase function. This does not imply constitutive nuclear localization; cytoplasm remains the primary compartment for canonical tRNA charging and editing.
Supporting Evidence:
PMID:38512451
addition of lactate significantly promoted the nuclear localization of WT AARS1 but not the Ξ”NLS mutant
GO:0005737 cytoplasm
IDA
PMID:38512451
The alanyl-tRNA synthetase AARS1 moonlights as a lactyltrans...
ACCEPT
Summary: Direct cytoplasmic localization with lactate-triggered shuttling to the nucleus.
Reason: The cytoplasm is the primary setting for canonical AARS1 charging/editing.
Supporting Evidence:
PMID:38512451
AARS1, commonly understood as an enzyme residing in the cytoplasm
GO:0035332 positive regulation of hippo signaling
IDA
PMID:38512451
The alanyl-tRNA synthetase AARS1 moonlights as a lactyltrans...
MARK AS OVER ANNOTATED
Summary: The study directly demonstrates AARS1-dependent lactylation and activation of nuclear YAP/TEAD. GO:0035329, the regulated process, specifically describes the MST/LATS kinase cascade that phosphorylates and inactivates YAP.
Reason: The experiments support activation of the downstream YAP-TEAD transcriptional complex, not increased activity of the GO-defined Hippo kinase cascade. Conversely, YAP-TEAD activation alone does not demonstrate inhibition of MST/LATS, so replacing this annotation with negative regulation of hippo signaling would also exceed the evidence. Retain the directly supported lactyltransferase activity and conditional nuclear localization; the pathway-regulation assertion is over-scoped. The direct process under consideration is peptidyl-lysine lactylation, described in proposed_new_terms; no available replacement is asserted as regulation of the MST/LATS cascade.
Supporting Evidence:
PMID:38512451
AARS1 translocated into the nucleus, where it directly catalyzed lactylation of YAP at K90 and TEAD1 at K108, thereby activating downstream target gene expression to promote tumor cell proliferation.
GO:0141207 peptide lactyltransferase (ATP-dependent) activity
IDA
PMID:38512451
The alanyl-tRNA synthetase AARS1 moonlights as a lactyltrans...
ACCEPT
Summary: Purified AARS1 uses lactate and ATP to lactylate protein and peptide substrates, with cellular validation.
Reason: The paper directly supports the GO reaction; qualify the activity to elevated-lactate contexts and do not infer dominance over basal global Kla.
Supporting Evidence:
PMID:38512451
AARS1 was able to directly lactylate histone H3 and H4 in a manner dependent on both lactate and ATP
GO:0141207 peptide lactyltransferase (ATP-dependent) activity
IDA
PMID:38653238
Alanyl-tRNA synthetase, AARS1, is a lactate sensor and lacty...
ACCEPT
Summary: Direct AARS1-mediated lactate-AMP formation followed by transfer to lysine acceptors.
Reason: The exact reaction is corroborated independently; it is condition- and substrate-dependent rather than the principal basal-global Kla source.
Supporting Evidence:
PMID:38653238
AARS1 binds to lactate and catalyzes the formation of lactate-AMP, followed by transfer of lactate to the lysince acceptor residue.
GO:1901797 negative regulation of signal transduction by p53 class mediator
IDA
PMID:38653238
Alanyl-tRNA synthetase, AARS1, is a lactate sensor and lacty...
KEEP AS NON CORE
Summary: AARS1-dependent lactylation of p53 K120/K139 inhibits p53 phase separation, DNA binding and transcriptional activation in tumor models.
Reason: The negative effect on p53 signaling is supported but is a downstream high-lactate tumor-context consequence.
Supporting Evidence:
PMID:38653238
AARS1 lactylation of p53 hinders its liquid-liquid phase separation, DNA binding, and transcriptional activation.
GO:0006418 tRNA aminoacylation for protein translation
TAS
Reactome:R-HSA-379716
MODIFY
Summary: Reactome places AARS1 in the broad cytosolic tRNA-aminoacylation pathway.
Reason: Use the alanine-specific aminoacylation process. GO:0006419 is retained as the consistent level across the reviewed source annotations; cytosolic execution is represented separately by the accepted localization annotations.
Proposed replacements: alanyl-tRNA aminoacylation
GO:0006419 alanyl-tRNA aminoacylation
IMP
PMID:33909043
Protein instability associated with AARS1 and MARS1 mutation...
ACCEPT
Summary: Destabilizing AARS1 variants reduce the rate of tRNA charging in patient fibroblasts.
Reason: The mutant phenotype directly supports the core alanyl-tRNA aminoacylation process.
Supporting Evidence:
PMID:33909043
Functional studies in skin fibroblasts from affected individuals demonstrate that these new variants also impact on the rate of tRNA charging
GO:0002196 Ser-tRNA(Ala) deacylase activity
ISS
GO_REF:0000024
ACCEPT
Summary: Curator-reviewed similarity transfer of Ser-tRNA(Ala) deacylase activity from mouse Aars, independently validated by human assays.
Reason: Human AARS1 directly deacylates Ser-tRNA(Ala), so the transfer captures a core editing activity.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
UniProtKB:Q8BGQ7 SUPPORTS TRANSFER
Mouse Aars is the orthologous donor. QuickGO retains experimental editing/fidelity evidence; human AARS1 charging and Ser-tRNA(Ala) editing independently corroborate the relevant conserved function (PMID:28493438).
Supporting Evidence:
PMID:28493438
An in vitro editing activity assay was carried out using [3H] Ser-tRNAAla as a substrate.
GO:0006400 tRNA modification
ISS
GO_REF:0000024
MODIFY
Summary: Curator-reviewed transfer of tRNA modification from mouse Aars, intended to represent AlaRS editing.
Reason: Editing removes the attached amino acid rather than modifying tRNA nucleotides; use the mechanistically correct fidelity process.
Propagation Review
Root cause: TERM SCOPING PROBLEM
Failure modes: ROLE CONFLATION
Sources checked:
UniProtKB:Q8BGQ7 SOURCE BAD
QuickGO retains mouse Aars tRNA-modification annotations from PMID:16906134, PMID:25422440 and PMID:29769718. Those studies concern editing of aminoacyl-tRNA, whereas GO:0006400 requires covalent alteration of tRNA nucleotides. The source term choice, not orthology, is the issue.
GO:0002161 aminoacyl-tRNA deacylase activity
IDA
PMID:28493438
Deficient activity of alanyl-tRNA synthetase underlies an au...
ACCEPT
Summary: Direct human editing assay demonstrates AARS1 hydrolysis of mischarged Ser-tRNA(Ala), including loss of deacylation by an editing-domain disease variant.
Reason: The Ser-tRNA(Ala) assay directly supports this true broader aminoacyl-tRNA deacylase parent activity. The more specific activity is already represented by existing GO:0002196 annotations, which cite this study as direct corroboration.
Supporting Evidence:
PMID:28493438
An in vitro editing activity assay was carried out using [3H] Ser-tRNAAla as a substrate.
GO:0004813 alanine-tRNA ligase activity
IDA
PMID:28493438
Deficient activity of alanyl-tRNA synthetase underlies an au...
ACCEPT
Summary: Direct alanine-dependent aminoacylation measurements using recombinant wild-type and disease-variant human AARS1.
Reason: The assay directly establishes the substrate-specific core molecular function.
Supporting Evidence:
PMID:28493438
The aminoacylation activities of both variants were then tested using 14C-labeled alanine with various concentrations of tRNA.
GO:0006419 alanyl-tRNA aminoacylation
IDA
PMID:28493438
Deficient activity of alanyl-tRNA synthetase underlies an au...
ACCEPT
Summary: Direct human AARS1 aminoacylation data, with disease variants reducing catalytic efficiency.
Reason: The measured reaction is the conserved core alanyl-tRNA aminoacylation process.
Supporting Evidence:
PMID:28493438
The p.Gly913Asp mutation led to a 73% decrease in catalytic efficiency.
GO:0004813 alanine-tRNA ligase activity
IDA
PMID:27622773
Evolutionary Gain of Alanine Mischarging to Noncognate tRNAs...
ACCEPT
Summary: Recombinant human AARS1 charges cognate tRNA(Ala) and can also mischarge selected noncognate tRNAs.
Reason: The data directly establish alanine-tRNA ligase activity; limited noncognate charging does not negate the cognate core function.
Supporting Evidence:
PMID:27622773
for human AlaRS, in addition to the cognate tRNAAla species, we readily detected 3H-signals for cytoplasmic tRNACys(GCA), tRNAThr(CGT/IGT)
GO:0006419 alanyl-tRNA aminoacylation
IDA
PMID:27622773
Evolutionary Gain of Alanine Mischarging to Noncognate tRNAs...
ACCEPT
Summary: Direct human AARS1 assays show charging of cognate tRNA(Ala).
Reason: This directly supports the core process, notwithstanding the study's additional discovery of limited noncognate charging.
Supporting Evidence:
PMID:27622773
Remarkably, for human AlaRS, in addition to the cognate tRNAAla species, we readily detected 3H-signals for cytoplasmic tRNACys(GCA), tRNAThr(CGT/IGT) (but not tRNAThr(TGT)), and mitochondrial tRNAAsp (mt-tRNAAsp) (Fig. 1b).
GO:0016020 membrane
HDA
PMID:19946888
Defining the membrane proteome of NK cells.
UNDECIDED
Summary: GOA assigns membrane localization from the NK-cell membrane proteome survey. The accessible abstract describes the fractionation method but does not expose the AARS1-specific identification or fraction-association evidence.
Reason: The full text and AARS1-specific proteomic evidence could not be accessed. AARS1 being soluble and lacking a transmembrane segment does not exclude peripheral or transient membrane association. Without the curator's supporting table, neither acceptance nor rejection of this experimental localization can be justified; leave it unresolved.
Supporting Evidence:
PMID:19946888
The remaining species were largely involved in cellular processes and molecular functions that could be predicted to be transiently associated with membranes.
GO:0070062 extracellular exosome
HDA
PMID:20458337
MHC class II-associated proteins in B-cell exosomes and pote...
UNDECIDED
Summary: GOA assigns extracellular-exosome localization from the B-cell exosome proteome study. Its abstract reports 539 proteins but does not identify AARS1 individually.
Reason: The publisher lists supplementary proteomics tables, but full-text and table retrieval returned HTTP 403. The abstract alone cannot verify the AARS1-specific detection, so retain the source tuple as UNDECIDED rather than infer a verified exosomal role. If the identification is confirmed, it would remain a context-specific localization, not a core extracellular catalytic function.
Supporting Evidence:
PMID:20458337
analyzed the total proteome of highly purified B cell-derived exosomes using sensitive and accurate mass spectrometry
GO:0005829 cytosol
TAS
Reactome:R-HSA-379864
ACCEPT
Summary: Reactome places AARS1 in the cytosol for its alanine-tRNA charging reaction.
Reason: The compartment is appropriate for the cytoplasmic enzyme and is corroborated by HPA.
GO:0000049 tRNA binding
TAS
PMID:7654687
Human alanyl-tRNA synthetase: conservation in evolution of c...
ACCEPT
Summary: Author-statement annotation for tRNA binding based on human AlaRS recognition/aminoacylation of tRNA(Ala)-derived acceptor helices.
Reason: The cited biochemical work directly demonstrates recognition of tRNA-derived RNA substrates.
Supporting Evidence:
PMID:7654687
both the E. coli enzyme and the human enzyme purified from Pichia aminoacylate 9-base pair RNA duplexes
GO:0005737 cytoplasm
TAS
PMID:7654687
Human alanyl-tRNA synthetase: conservation in evolution of c...
ACCEPT
Summary: Author-statement assignment of cloned human AlaRS to the cytoplasm.
Reason: This agrees with independent cytoplasm/cytosol evidence; the abstract-only cache gives no reason to overrule the curator.
GO:0006419 alanyl-tRNA aminoacylation
TAS
PMID:7761427
Wide cross-species aminoacyl-tRNA synthetase replacement in ...
ACCEPT
Summary: Author statement for alanyl-tRNA aminoacylation, supported by rescue of yeast lacking cytoplasmic AlaRS with human AARS1.
Reason: Cross-species complementation demonstrates accurate AARS1 aminoacylation in vivo.
Supporting Evidence:
PMID:7761427
Growth of cells harboring the ala1 disrupted allele was restored by a cDNA clone encoding human alanyl-tRNA synthetase
GO:0008033 tRNA processing
TAS
PMID:7654687
Human alanyl-tRNA synthetase: conservation in evolution of c...
MODIFY
Summary: The cited study establishes tRNA recognition/aminoacylation, not pre-tRNA maturation; GO:0008033 explicitly precedes aminoacyl-group addition.
Reason: The tRNA-directed biology is valid but the process term is wrong; use the alanine-specific aminoacylation process.
Proposed replacements: alanyl-tRNA aminoacylation
Supporting Evidence:
PMID:7654687
both the E. coli enzyme and the human enzyme purified from Pichia aminoacylate 9-base pair RNA duplexes

Core Functions

Cytosolic AARS1 activates L-alanine with ATP and transfers alanine to tRNA(Ala), producing Ala-tRNA(Ala) for cytoplasmic protein synthesis. This substrate-specific aminoacylation reaction is the enzyme's primary conserved activity.

Molecular Function:
alanine-tRNA ligase activity
Directly Involved In:
Cellular Locations:
Supporting Evidence:
  • PMID:28493438
    The aminoacylation activities of both variants were then tested using 14C-labeled alanine with various concentrations of tRNA.
  • Reactome:R-HSA-379864
    AARS (cytosolic alanyl tRNA synthetase) catalyzes the reaction of alanine, tRNA(ala), and ATP to form Ala tRNA(Ala), AMP, and pyrophosphate.

The embedded AARS1 editing apparatus proofreads mischarged tRNA(Ala) and hydrolyzes the incorrect aminoacyl ester. Ser-tRNA(Ala) deacylation is directly demonstrated with human AARS1; Gly-tRNA(Ala) is a plausible conserved substrate but was not directly tested in the human studies examined here. This post-transfer editing preserves cytoplasmic translational fidelity.

Supporting Evidence:
  • PMID:28493438
    An in vitro editing activity assay was carried out using [3H] Ser-tRNAAla as a substrate.
  • PMID:28493438
    tRNAAla can be mischarged with serine and glycine by AARS to yield Ser-tRNAAla and Gly-tRNAAla, respectively [Tsui and Fersht 1981]. To maintain the fidelity of aminoacylation, AARS possesses an editing domain that is capable of hydrolyzing the mischarged tRNAAla [Beebe et al. 2003; Guo et al. 2009].
  • PMID:19661429
    In this way, the editing domain checks for mischarging by picking out tRNAs that have Gly or Ser and a G3β€’U70 pair.

As a conditional secondary activity, AARS1 senses elevated intracellular L-lactate, forms lactoyl-AMP, and transfers lactyl groups to protein lysines. This activity can operate in the cytoplasm and, after lactate-induced nuclear import, in the nucleus on substrates including YAP1, TEAD1, and TP53. It is substrate- and context-dependent; AARS1 depletion did not reduce basal global lysine lactylation in untreated HEK293T cells.

Supporting Evidence:
  • PMID:38512451
    AARS1 was able to directly lactylate histone H3 and H4 in a manner dependent on both lactate and ATP
  • PMID:38512451
    addition of lactate significantly promoted the nuclear localization of WT AARS1 but not the Ξ”NLS mutant
  • PMID:38653238
    AARS1 binds to lactate and catalyzes the formation of lactate-AMP, followed by transfer of lactate to the lysince acceptor residue.
  • PMID:40835008
    However, the knockdown of either enzyme did not alter Kla levels (Fig. S6, B–E), suggesting the AARS pathway is also not required for global lysine lactylation.

References

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Suggested Questions for Experts

Q: How does the excess-lactate-dependent tRNA lactylation reported in PMID:42607683 compete with canonical alanyl-tRNA charging and protein lysine lactylation, and does it occur at endogenous AARS1 levels in non-tumor cells?

Q: Does full-length human AARS1 directly hydrolyze Gly-tRNA(Ala), and how do its catalytic efficiency and discrimination compare with Ser-tRNA(Ala) editing?

Q: Across physiological and pathological lactate concentrations, which endogenous protein substrates depend materially on AARS1 rather than class I HDACs or other lactylation routes, and in which cell states?

Q: Do AARS1 isoforms P49588-1 and P49588-2 differ in C-Ala-dependent editing, localization, oligomerization, DNA binding, or lactyltransferase activity?

Suggested Experiments

Experiment: Prepare homogeneous Gly-tRNA(Ala) and Ser-tRNA(Ala), then measure steady-state and single-turnover deacylation by purified full-length human AARS1. Include catalytic-site and editing-site mutants, uncharged tRNA(Ala), cognate Gly-tRNA(Gly) and Ser-tRNA(Ser), and Escherichia coli AlaRS controls to establish substrate specificity and support or reject a direct human GO:0106026 annotation.

Hypothesis: Full-length human AARS1 directly edits Gly-tRNA(Ala), but with kinetics distinct from its directly established Ser-tRNA(Ala) editing activity.

Type: biochemical enzyme kinetics

Experiment: Use acute endogenous AARS1 degradation across a calibrated intracellular lactate series, followed by isotope-resolved quantitative lactyl-proteomics and targeted measurement of YAP1, TEAD1, and TP53 sites. Rescue with matched-expression AARS1 variants that retain aminoacylation but differ in lactyltransferase activity, and compare with class I HDAC perturbation to separate AARS1-specific sites from the broader lactylome.

Hypothesis: Endogenous AARS1 contributes substantially to a restricted high-lactate, substrate-specific lactylome but not to basal global lysine lactylation.

Type: acute perturbation and quantitative proteomics

Experiment: Express P49588-1 and P49588-2 at matched endogenous levels in an AARS1-depleted human cell line and compare tRNA(Ala) charging, Ser/Gly-tRNA(Ala) editing, basal and lactate-induced localization, oligomeric state, DNA binding, and site-specific YAP1/TEAD1/TP53 lactylation. Parallel purified-protein assays should distinguish intrinsic isoform differences from cellular localization effects.

Hypothesis: The isoform-2 insertion within C-Ala changes AARS1 editing coordination or its conditional noncanonical activities without abolishing alanine charging.

Type: isoform-resolved biochemical and cell-rescue analysis

Knowledge Gaps

What is not known β€” curated, literature-grounded statements of the open unknowns (the inverse of core functions).

Gap: Direct full-length human AARS1 Gly-tRNA(Ala) deacylation, and its kinetic specificity relative to Ser-tRNA(Ala), were not established in the human studies examined here.

OPEN BIOLOGYCURATION RESIDUAL_SUBGAP

What is known: Recombinant human AARS1 directly deacylates Ser-tRNA(Ala). Conserved AlaRS-family experiments identify both glycine and serine errors, and human C-Ala restores an Escherichia coli editing construct. These observations motivate a human glycine-editing hypothesis but do not provide a verified source for a GO ISS transfer.

Significance: Direct human kinetics would determine whether GO:0106026 should be supported by IDA and whether glycine and serine errors are cleared with comparable efficiency.

What would resolve it: Measure steady-state and single-turnover deacylation of purified Gly-tRNA(Ala) and Ser-tRNA(Ala) by full-length recombinant human AARS1, with editing-site mutants and the bacterial enzyme as controls.

Provenance (the field's own admissions):

Gap: The physiological lactate range, cell states, and substrate spectrum in which endogenous AARS1 makes a material contribution to protein lysine lactylation, relative to other enzymatic routes, remain incompletely defined.

OPEN BIOLOGYCURATION RESIDUAL_SUBGAP

What is known: ATP-dependent AARS1 lactyltransferase chemistry and several target-specific effects are supported under elevated-lactate tumor conditions, but AARS1 knockdown did not lower basal global lysine lactylation in untreated HEK293T cells and the reported lactoyl-AMP reaction has a millimolar lactate Km.

Significance: Resolving this boundary would distinguish physiological AARS1 substrates from high-lactate or overexpression effects and prevent substrate-specific activity from being generalized to the basal global lactylome.

What would resolve it: Quantify endogenous, site-resolved lactylation across a calibrated intracellular lactate series after acute AARS1 depletion and matched rescue, alongside perturbation of class I HDAC-dependent lactylation and measurement of AARS1 charging activity.

Provenance (the field's own admissions):

Gap: It is unknown whether the two human AARS1 isoforms differ in aminoacylation, editing, lactate-responsive localization, or lactyltransferase activity, and whether the isoform-2 insertion within C-Ala changes the domain's cellular role.

OPEN BIOLOGY RESIDUAL_SUBGAP

What is known: UniProt records two splice isoforms, while structural work establishes distinctive DNA-binding and oligomeric surfaces for human C-Ala only in isolated-domain or structural assays; no isoform-specific core function is assigned here.

Significance: Isoform-specific activity could alter translational quality control or conditional lactylation without being visible in canonical-sequence annotations.

What would resolve it: Compare endogenous-level P49588-1 and P49588-2 rescue constructs in an AARS1-depleted human cell background for charging, editing, localization, oligomerization, DNA binding, and target-specific lactylation.

Provenance (the field's own admissions):

Deep Research

Falcon

(AARS1-deep-research-falcon.md)

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πŸ“š Additional Documentation

Notes

(AARS1-notes.md)

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