Seroatlas · Human Serome Atlas

AP1S3

AP-1 complex subunit sigma-3

Also known as: AP1S3_HUMAN, sigma1C

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

Protein identityUniProt · HPA

UniProt accession
Q96PC3
Gene
AP1S3
Ensembl
ENSG00000152056
Chromosome
2
Canonical length
154 aa
Protein class
Disease related genes, Human disease related genes, Predicted intracellular proteins
Subcellular location
Vesicles

OverviewNCBI Gene

This gene encodes a member of the adaptor-related protein complex 1, sigma subunit genes. The encoded protein is a component of adaptor protein complex 1 (AP-1), one of the AP complexes involved in claathrin-mediated vesicular transport from the Golgi or endosomes. Disruption of the pathway for display of HIV-1 antigens, which prevents recognition of the virus by cytotoxic T cells, has been shown to involve the AP-1 complex (PMID: 15569716). Alternative splicing results in multiple transcript variants. [provided by RefSeq, Mar 2014]

Canonical amino-acid sequenceUniProt

154 residues, UniProt reviewed canonical sequence.

>Q96PC3|AP1S3
     1  MIHFILLFSR QGKLRLQKWY ITLPDKERKK ITREIVQIIL SRGHRTSSFV DWKELKLVYK
    61  RYASLYFCCA IENQDNELLT LEIVHRYVEL LDKYFGNVCE LDIIFNFEKA YFILDEFIIG
   121  GEIQETSKKI AVKAIEDSDM LQEVSTVSQT MGER

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against AP1S3 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)
0.31
Highest tissue expression
46 nTPM

Expression across tissuesHPA

Tissue

  • epididymis: 46 nTPM
  • thyroid gland: 13 nTPM
  • stomach: 8.6 nTPM
  • urinary bladder: 7 nTPM
  • placenta: 5.7 nTPM
  • kidney: 5 nTPM

Single-cell type

  • loop of henle epithelial cells: 150 nCPM
  • epididymal principal cells: 106 nCPM
  • papillary tip epithelial cells: 89 nCPM
  • cytotrophoblasts: 85 nCPM
  • alveolar cells type 1: 77 nCPM
  • mast cells: 66 nCPM

Immune cell

  • basophil: 5.6 nTPM
  • memory B-cell: 4.6 nTPM
  • plasmacytoid DC: 3.8 nTPM
  • naive B-cell: 2.5 nTPM
  • neutrophil: 2.1 nTPM
  • myeloid DC: 1.1 nTPM

Brain region

  • cerebellum: 13 nTPM
  • cerebral cortex: 12 nTPM
  • basal ganglia: 12 nTPM
  • amygdala: 12 nTPM
  • hypothalamus: 12 nTPM
  • medulla oblongata: 11 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about AP1S3.

Disease | AllUniProt

Conditions AP1S3 is implicated in, by any mechanism.

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)
1.08
gnomAD pLI
0.02
gnomAD missense Z
0.51
DepMap mean gene effect
-0.04
DepMap dependency class
none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of AP1S3 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 AP1S3 as an antibody target. Whether an autoantibody or antibody against AP1S3 could matter depends on whether native AP1S3 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

AP1S3 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 AP1S3 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/AP1S3. 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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