Seroatlas · Human Serome Atlas

SPAAR

Small regulatory polypeptide of amino acid response

Also known as: LINC00961, SPAR, SPAR_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
A0A1B0GVQ0
Gene
SPAAR
Ensembl
ENSG00000235387
Chromosome
9
Canonical length
90 aa
Protein class
Predicted intracellular proteins

OverviewNCBI Gene

Involved in cellular response to amino acid stimulus and negative regulation of TORC1 signaling. Located in late endosome membrane and lysosomal proton-transporting V-type ATPase complex. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

90 residues, UniProt reviewed canonical sequence.

>A0A1B0GVQ0|SPAAR
     1  MGAKAPRGPK VAQWAMETAV IGVVVVLFVV TVAITCVLCC FSCDSRAQDP QGGPGRSFTV
    61  ATFRQEASLF TGPVRHAQPV PSAQDFWTFM

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against SPAAR 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
Other membrane
Secreted
No
Transmembrane segments
1
Mean surface accessibility (rSASA)
0.61
Highest tissue expression
12 nTPM

Expression across tissuesHPA

Tissue

  • adipose tissue: 12 nTPM
  • breast: 11 nTPM
  • heart muscle: 8.7 nTPM
  • testis: 7.2 nTPM
  • placenta: 4.4 nTPM
  • kidney: 4 nTPM

Single-cell type

  • sertoli cells: 179 nCPM
  • vascular endothelial cells: 56 nCPM
  • adipocytes: 45 nCPM
  • fibro-adipogenic progenitors: 40 nCPM
  • retinal bipolar cells: 17 nCPM
  • alveolar cells type 1: 13 nCPM

Immune cell

  • basophil: 0 nTPM
  • classical monocyte: 0 nTPM
  • eosinophil: 0 nTPM
  • gdT-cell: 0 nTPM
  • intermediate monocyte: 0 nTPM
  • MAIT T-cell: 0 nTPM

Brain region

  • thalamus: 5 nTPM
  • pons: 4.4 nTPM
  • amygdala: 4 nTPM
  • cerebral cortex: 4 nTPM
  • medulla oblongata: 3.8 nTPM
  • midbrain: 3.4 nTPM

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 3% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Cellular components

Protein domainsUniProt · Pfam · InterPro

  • Small regulatory polypeptide of amino acid response
  • Small regulatory polypeptide of amino acid response

KeywordsUniProt

InteractionsUniProt · HPA

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

SPAAR 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 SPAAR as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/SPAAR. 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).

© 2026 · Seroatlas, Discover Oregon LLC · Terms of use

Loading the interactive Seroatlas protein explorer...