Seroatlas · Human Serome Atlas

AP1S1

AP-1 complex subunit sigma-1A

Also known as: AP19, AP1S1_HUMAN, CLAPS1, EKV3, SIGMA1A, WUGSC:H_DJ0747G18.2

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

Protein identityUniProt · HPA

UniProt accession
P61966
Gene
AP1S1
Ensembl
ENSG00000106367
Chromosome
7
Canonical length
158 aa
Protein class
Disease related genes, Human disease related genes, Plasma proteins, Potential drug targets, Predicted intracellular proteins, Transporters
Subcellular location
Golgi apparatus,Vesicles

OverviewNCBI Gene

The protein encoded by this gene is part of the clathrin coat assembly complex which links clathrin to receptors in coated vesicles. These vesicles are involved in endocytosis and Golgi processing. This protein, as well as beta-prime-adaptin, gamma-adaptin, and the medium (mu) chain AP47, form the AP-1 assembly protein complex located at the Golgi vesicle. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

158 residues, UniProt reviewed canonical sequence.

>P61966|AP1S1
     1  MMRFMLLFSR QGKLRLQKWY LATSDKERKK MVRELMQVVL ARKPKMCSFL EWRDLKVVYK
    61  RYASLYFCCA IEGQDNELIT LELIHRYVEL LDKYFGSVCE LDIIFNFEKA YFILDEFLMG
   121  GDVQDTSKKS VLKAIEQADL LQEEDESPRS VLEEMGLA

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against AP1S1 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
116 nTPM

Expression across tissuesHPA

Tissue

  • basal ganglia: 116 nTPM
  • cerebral cortex: 105 nTPM
  • amygdala: 88 nTPM
  • hippocampal formation: 68 nTPM
  • kidney: 48 nTPM
  • hypothalamus: 44 nTPM

Single-cell type

  • enterocytes: 209 nCPM
  • migrating cytotrophoblasts: 206 nCPM
  • cytotrophoblasts: 197 nCPM
  • esophageal basal cells: 147 nCPM
  • esophageal suprabasal cells: 140 nCPM
  • enteric transient amplifying cells: 128 nCPM

Immune cell

  • plasmacytoid DC: 5.1 nTPM
  • myeloid DC: 4.6 nTPM
  • classical monocyte: 3.3 nTPM
  • T-reg: 3.3 nTPM
  • memory CD4 T-cell: 3.2 nTPM
  • intermediate monocyte: 3.1 nTPM

Brain region

  • cerebral cortex: 114 nTPM
  • basal ganglia: 94 nTPM
  • amygdala: 87 nTPM
  • hippocampal formation: 83 nTPM
  • thalamus: 68 nTPM
  • white matter: 66 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about AP1S1.

Disease | AllUniProt

Conditions AP1S1 is implicated in, by any mechanism.

Disease | GeneticClinVar

9 pathogenic / likely-pathogenic of 161 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

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)
0.86
gnomAD pLI
0.1
gnomAD missense Z
1.74
DepMap mean gene effect
-0.06
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 9% 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 AP1S1 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 AP1S1 as an antibody target. Whether an autoantibody or antibody against AP1S1 could matter depends on whether native AP1S1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

AP1S1 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 AP1S1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/AP1S1. 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...