DARS1

DARS1 is the cytoplasmic aspartyl-tRNA synthetase whose aminoacylation activity is essential for early development—complete loss is embryonic lethal in mice—and whose dosage and enzymatic competence shape neuronal protein synthesis and myelination (PMID:27816769, PMID:33551752). In neurons the enzyme concentrates in the soma alongside the translation machinery and extends into neurites and synapses, consistent with a role in local protein synthesis (PMID:27816769), while reduced enzyme activity from hypomorphic and pathogenic point alleles (e.g. M256L) produces white-matter vacuolization, demyelination with loss of major myelin proteins, and systemic metabolic alterations, recapitulating HBSL leukodystrophy (PMID:33551752, PMID:35357600). The aminoacylation function also tunes translational output in a substrate-biased manner: DARS1 overexpression in hepatocellular carcinoma cells reshapes the proteome toward high-aspartate-content proteins (PMID:41790991). Beyond canonical charging, DARS1 has non-canonical roles—it localizes to the nucleus of HCC cells where it associates with the SAGA co-activator complex (including SUPT7L) to sustain MYC protein levels and oncogenic signaling (PMID:41790991), and in myeloproliferative neoplasm cells it acts upstream of PI3K/AKT to drive proliferation and survival (PMID:42177774). It has additionally been identified as a cellular target of an anti-HIV compound that modulates viral replication (PMID:34338505).

1. 2016 Medium

   Established that DARS1 is developmentally essential and positioned in neurons where local translation occurs, framing it as more than a housekeeping enzyme.

   Evidence Immunohistochemistry, immunofluorescence and subcellular fractionation plus a Dars-null knockout mouse

   PMID:27816769

   Open questions at the time

   • Embryonic lethality of the null prevents dissection of tissue-specific requirements
   • Co-localization with translation machinery does not directly demonstrate local aminoacylation at synapses
2. 2016 Medium

   Showed DARS1 dosage influences neural function, as heterozygous hypomorphs have behavioral (pre-pulse inhibition) deficits absent overt motor pathology.

   Evidence Acoustic startle pre-pulse inhibition testing in heterozygous knockout mice

   PMID:27816769

   Open questions at the time

   • Molecular basis linking reduced DARS1 to attentional processing not defined
   • Single behavioral readout
3. 2021 Medium

   Demonstrated causally that reduced DARS1 enzymatic activity drives hypomyelination pathology, modeling HBSL leukodystrophy.

   Evidence Compound heterozygous hypomorphic point-mutation/null mouse, histopathology and Western blot for myelin proteins

   PMID:33551752

   Open questions at the time

   • Mechanism connecting aminoacylation deficit to selective myelin protein loss unresolved
   • Cell-type origin of demyelination not pinpointed
4. 2022 Medium

   Extended DARS1 function beyond the CNS by showing a pathogenic M256L allele with partial activity causes developmental, structural, and metabolic phenotypes.

   Evidence Dars1 M256L/- knock-in mouse with histopathology and metabolic phenotyping

   PMID:35357600

   Open questions at the time

   • Mechanism linking aminoacylation to altered energy metabolism unknown
   • Whether metabolic effects are secondary to systemic illness untested
5. 2021 Medium

   Identified DARS1 as a druggable cellular target whose levels modulate HIV replication, a function outside canonical translation.

   Evidence Photoaffinity labeling and LC-MS/MS with DARS1 overexpression/knockdown in HEK293T antiviral assays

   PMID:34338505

   Open questions at the time

   • Mechanism by which DARS1 affects viral replication not defined
   • Direct compound-binding site only inferred by docking
6. 2026 Medium

   Revealed a non-canonical nuclear role: DARS1 associates with the SAGA co-activator complex to sustain MYC-driven oncogenic signaling in hepatocellular carcinoma.

   Evidence Quantitative interactor proteomics, co-IP, nuclear fractionation, phospho-MYC Western blot, and in vivo xenograft/orthotopic models

   PMID:41790991

   Open questions at the time

   • Whether SAGA association requires aminoacylation activity unknown
   • Direct vs indirect nature of the DARS1-SUPT7L interaction not resolved
7. 2026 Medium

   Connected DARS1 aminoacylation to proteome composition, showing overexpression biases translation toward high-aspartate-content proteins.

   Evidence Quantitative proteomic profiling of DARS1-overexpressing versus control HCC cells

   PMID:41790991

   Open questions at the time

   • Causal link between aspartate-tRNA charging rate and enriched protein set not directly tested
   • Single cell-line context
8. 2026 Medium

   Placed DARS1 upstream of PI3K/AKT signaling in myeloproliferative neoplasm cells, defining a proliferation/survival pathway dependence.

   Evidence DARS1 depletion in MPN cell lines and xenografts, transcriptomics/metabolomics, and PI3K/AKT reactivation rescue

   PMID:42177774

   Open questions at the time

   • Molecular mechanism by which DARS1 engages PI3K/AKT undefined
   • Whether the effect requires aminoacylation activity untested

• It remains unknown whether DARS1's non-canonical nuclear, signaling, and antiviral activities depend on its aminoacylation catalytic function or represent moonlighting roles.
• No catalytic-dead separation-of-function experiments reported
• Structural basis for SAGA or compound interaction not determined