Seroatlas · Human Serome Atlas

ACP1

Low molecular weight phosphotyrosine protein phosphatase

Also known as: HAAP, LMW-PTP, LMWPTP, PPAC_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
P24666
Gene
ACP1
Ensembl
ENSG00000143727
Chromosome
2
Canonical length
158 aa
Protein class
Enzymes, Plasma proteins, Predicted intracellular proteins
Subcellular location
Nucleoplasm,Cytosol

OverviewNCBI Gene

The product of this gene belongs to the phosphotyrosine protein phosphatase family of proteins. It functions as an acid phosphatase and a protein tyrosine phosphatase by hydrolyzing protein tyrosine phosphate to protein tyrosine and orthophosphate. This enzyme also hydrolyzes orthophosphoric monoesters to alcohol and orthophosphate. This gene is genetically polymorphic, and three common alleles segregating at the corresponding locus give rise to six phenotypes. Each allele appears to encode at least two electrophoretically different isozymes, Bf and Bs, which are produced in allele-specific ratios. Multiple alternatively spliced transcript variants encoding distinct isoforms have been identified for this gene. [provided by RefSeq, Aug 2008]

Canonical amino-acid sequenceUniProt

158 residues, UniProt reviewed canonical sequence.

>P24666|ACP1
     1  MAEQATKSVL FVCLGNICRS PIAEAVFRKL VTDQNISENW RVDSAATSGY EIGNPPDYRG
    61  QSCMKRHGIP MSHVARQITK EDFATFDYIL CMDESNLRDL NRKSNQVKTC KAKIELLGSY
   121  DPQKQLIIED PYYGNDSDFE TVYQQCVRCC RAFLEKAH

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against ACP1 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)
0.26
Highest tissue expression
102 nTPM

Expression across tissuesHPA

Tissue

  • adrenal gland: 102 nTPM
  • liver: 101 nTPM
  • choroid plexus: 92 nTPM
  • pancreas: 90 nTPM
  • bone marrow: 88 nTPM
  • kidney: 75 nTPM

Single-cell type

  • late spermatids: 3,346 nCPM
  • early spermatids: 1,247 nCPM
  • gastric progenitor cells: 488 nCPM
  • extravillous trophoblasts: 336 nCPM
  • esophageal suprabasal cells: 288 nCPM
  • migrating cytotrophoblasts: 278 nCPM

Immune cell

  • NK-cell: 122 nTPM
  • T-reg: 118 nTPM
  • MAIT T-cell: 118 nTPM
  • naive CD4 T-cell: 117 nTPM
  • total PBMC: 115 nTPM
  • naive CD8 T-cell: 115 nTPM

Brain region

  • choroid plexus: 89 nTPM
  • white matter: 57 nTPM
  • cerebral cortex: 56 nTPM
  • hypothalamus: 53 nTPM
  • basal ganglia: 52 nTPM
  • thalamus: 49 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)
1.8
gnomAD pLI
0
gnomAD missense Z
-0.25
DepMap mean gene effect
0.05
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

  • Phosphotyrosine protein phosphatase I superfamily
  • Protein-tyrosine phosphatase, low molecular weight, mammalian
  • Protein-tyrosine phosphatase, low molecular weight
  • Phosphotyrosine protein phosphatase I
  • Low Molecular Weight Phosphotyrosine Protein Phosphatase
  • Low molecular weight phosphotyrosine protein phosphatase

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of ACP1 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 ACP1 as an antibody target. Whether an autoantibody or antibody against ACP1 could matter depends on whether native ACP1 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

ACP1 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 ACP1 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/ACP1. 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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