Seroatlas · Human Serome Atlas

UPK1A

Uroplakin-1a

Also known as: TSPAN21, UPK1A_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
O00322
Gene
UPK1A
Ensembl
ENSG00000105668
Chromosome
19
Canonical length
258 aa
Protein class
Predicted membrane proteins, Transporters
Quaternary structure
Homodimer

OverviewNCBI Gene

The protein encoded by this gene is a member of the transmembrane 4 superfamily, also known as the tetraspanin family. Most of these members are cell-surface proteins that are characterized by the presence of four hydrophobic domains. The proteins mediate signal transduction events that play a role in the regulation of cell development, activation, growth and motility. This encoded protein is found in the asymmetrical unit membrane (AUM) where it can complex with other transmembrane 4 superfamily proteins. It may play a role in normal bladder epithelial physiology, possibly in regulating membrane permeability of superficial umbrella cells or in stabilizing the apical membrane through AUM/cytoskeletal interactions. The protein may also play a role in tumor suppression. Alternative splicing results in multiple transcript variants of this gene. [provided by RefSeq, Jul 2013]

Canonical amino-acid sequenceUniProt

258 residues, UniProt reviewed canonical sequence.

>O00322|UPK1A
     1  MASAAAAEAE KGSPVVVGLL VVGNIIILLS GLSLFAETIW VTADQYRVYP LMGVSGKDDV
    61  FAGAWIAIFC GFSFFMVASF GVGAALCRRR SMVLTYLVLM LIVYIFECAS CITSYTHRDY
   121  MVSNPSLITK QMLTFYSADT DQGQELTRLW DRVMIEQECC GTSGPMDWVN FTSAFRAATP
   181  EVVFPWPPLC CRRTGNFIPL NEEGCRLGHM DYLFTKGCFE HIGHAIDSYT WGISWFGFAI
   241  LMWTLPVMLI AMYFYTML

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against UPK1A 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
Cell surface
Secreted
No
Transmembrane segments
4
Mean surface accessibility (rSASA)
0.28
Highest tissue expression
122 nTPM

Expression across tissuesHPA

Tissue

  • urinary bladder: 122 nTPM
  • vagina: 29 nTPM
  • esophagus: 24 nTPM
  • skin: 14 nTPM
  • cervix: 11 nTPM
  • prostate: 5.7 nTPM

Single-cell type

  • urothelial cells: 588 nCPM
  • esophageal apical cells: 248 nCPM
  • prostatic club cells: 187 nCPM
  • prostatic hillock cells: 95 nCPM
  • papillary tip epithelial cells: 69 nCPM
  • epididymal basal cells: 11 nCPM

Immune cell

  • memory CD4 T-cell: 0.4 nTPM
  • neutrophil: 0.3 nTPM
  • basophil: 0.2 nTPM
  • naive B-cell: 0.2 nTPM
  • NK-cell: 0.2 nTPM
  • memory B-cell: 0.1 nTPM

Brain region

  • cerebellum: 1.5 nTPM
  • cerebral cortex: 1.2 nTPM
  • hippocampal formation: 1.1 nTPM
  • hypothalamus: 1.1 nTPM
  • midbrain: 1 nTPM
  • thalamus: 1 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)
1.64
gnomAD pLI
0
gnomAD missense Z
-0.05
DepMap mean gene effect
-0.12
DepMap dependency class
selective

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

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads UPK1A as an antibody target. Whether an autoantibody or antibody against UPK1A could matter depends on whether native UPK1A is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

UPK1A is annotated at the cell surface, where native UPK1A is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label UPK1A as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/UPK1A. 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...