Seroatlas · Human Serome Atlas

CTU1

Cytoplasmic tRNA 2-thiolation protein 1

Also known as: ATPBD3, CTU1_HUMAN, MGC17332, NCS6

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession
Q7Z7A3
Gene
CTU1
Ensembl
ENSG00000142544
Chromosome
19
Canonical length
348 aa
Protein class
Predicted intracellular proteins
Subcellular location
Cytosol

OverviewNCBI Gene

Predicted to enable tRNA binding activity. Predicted to be involved in tRNA wobble position uridine thiolation. Located in cytosol. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

348 residues, UniProt reviewed canonical sequence.

>Q7Z7A3|CTU1
     1  MPAPPCASCH AARAALRRPL SGQALCGACF CAAFEAEVLH TVLAGRLLPP GAVVAVGASG
    61  GKDSTVLAHV LRALAPRLGI SLQLVAVDEG IGGYRDAALA AVRRQAARWE LPLTVVAYED
   121  LFGGWTMDAV ARSTAGSGRS RSCCTFCGVL RRRALEEGAR RVGATHIVTG HNADDMAETV
   181  LMNFLRGDAG RLARGGGLGS PGEGGALPRC RPLQFASQKE VVLYAHFRRL DYFSEECVYA
   241  PEAFRGHARD LLKRLEAARP SAVLDLVHSA ERLALAPAAR PPRPGACSRC GALASRALCQ
   301  ACALLDGLNR GRPRLAIGKG RRGLDEEATP GTPGDPARPP ASKAVPTF

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CTU1 can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability
Intracellular
Secreted
No
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.32
Highest tissue expression
6.2 nTPM

Expression across tissuesHPA

Tissue

  • ovary: 6.2 nTPM
  • cerebellum: 4.4 nTPM
  • esophagus: 4.4 nTPM
  • pancreas: 4.1 nTPM
  • endometrium: 4 nTPM
  • kidney: 3.9 nTPM

Single-cell type

  • alveolar cells type 1: 35 nCPM
  • suprabasal keratinocytes: 35 nCPM
  • basal keratinocytes: 25 nCPM
  • fallopian secretory cells: 19 nCPM
  • pancreatic acinar cells: 17 nCPM
  • breast secretory cells: 17 nCPM

Immune cell

  • classical monocyte: 0.1 nTPM
  • eosinophil: 0.1 nTPM
  • MAIT T-cell: 0.1 nTPM
  • memory CD8 T-cell: 0.1 nTPM
  • naive CD4 T-cell: 0.1 nTPM
  • naive CD8 T-cell: 0.1 nTPM

Brain region

  • medulla oblongata: 8.4 nTPM
  • white matter: 7.9 nTPM
  • cerebral cortex: 7.3 nTPM
  • pons: 7 nTPM
  • basal ganglia: 6.4 nTPM
  • midbrain: 6.3 nTPM

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance)
1.51
gnomAD pLI
0.07
gnomAD missense Z
1.7
DepMap mean gene effect
-0.36
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 6% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

  • cytosol
  • cytosolic tRNA wobble base thiouridylase complex

Protein domainsUniProt · Pfam · InterPro

  • Rossmann-like alpha/beta/alpha sandwich fold
  • Cytoplasmic tRNA 2-thiolation protein 1
  • tRNA(Ile)-lysidine/2-thiocytidine synthase, N-terminal
  • Cytoplasmic tRNA 2-thiolation protein 1, C-terminal
  • tRNA thiolation protein, TtcA/Ctu1 type
  • Cytoplasmic tRNA 2-thiolation protein 1-like, ATP-binding domain
  • PP-loop domain
  • Zinc-ribbon

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of CTU1 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads CTU1 as an antibody target. Whether an autoantibody or antibody against CTU1 could matter depends on whether native CTU1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CTU1 is annotated as predominantly intracellular. Intracellular proteins are common autoantibody markers, becoming visible to the immune system after cell injury or altered processing, but are usually markers of disease rather than direct drivers.

Annotation status

The present source text does not explicitly label CTU1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/CTU1. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

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