Seroatlas · Human Serome Atlas

ALPI

Intestinal-type alkaline phosphatase

Also known as: IAP, PPBI_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
P09923
Gene
ALPI
Ensembl
ENSG00000163295
Chromosome
2
Canonical length
528 aa
Protein class
Enzymes, Metabolic proteins, Predicted intracellular proteins
Subcellular location
Plasma membrane
Secretome location
Intracellular and membrane
Quaternary structure
Homodimer

OverviewNCBI Gene

There are at least four distinct but related alkaline phosphatases: intestinal, placental, placental-like, and liver/bone/kidney (tissue non-specific). The intestinal alkaline phosphatase gene encodes a digestive brush-border enzyme. This enzyme is a component of the gut mucosal defense system and is thought to function in the detoxification of lipopolysaccharide, and in the prevention of bacterial translocation in the gut. [provided by RefSeq, Dec 2014]

Canonical amino-acid sequenceUniProt

528 residues, UniProt reviewed canonical sequence.

>P09923|ALPI
     1  MQGPWVLLLL GLRLQLSLGV IPAEEENPAF WNRQAAEALD AAKKLQPIQK VAKNLILFLG
    61  DGLGVPTVTA TRILKGQKNG KLGPETPLAM DRFPYLALSK TYNVDRQVPD SAATATAYLC
   121  GVKANFQTIG LSAAARFNQC NTTRGNEVIS VMNRAKQAGK SVGVVTTTRV QHASPAGTYA
   181  HTVNRNWYSD ADMPASARQE GCQDIATQLI SNMDIDVILG GGRKYMFPMG TPDPEYPADA
   241  SQNGIRLDGK NLVQEWLAKH QGAWYVWNRT ELMQASLDQS VTHLMGLFEP GDTKYEIHRD
   301  PTLDPSLMEM TEAALRLLSR NPRGFYLFVE GGRIDHGHHE GVAYQALTEA VMFDDAIERA
   361  GQLTSEEDTL TLVTADHSHV FSFGGYTLRG SSIFGLAPSK AQDSKAYTSI LYGNGPGYVF
   421  NSGVRPDVNE SESGSPDYQQ QAAVPLSSET HGGEDVAVFA RGPQAHLVHG VQEQSFVAHV
   481  MAFAACLEPY TACDLAPPAC TTDAAHPVAA SLPLLAGTLL LLGASAAP

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against ALPI 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
0
Mean surface accessibility (rSASA)
0.26
Highest tissue expression
133 nTPM

Expression across tissuesHPA

Tissue

  • duodenum: 133 nTPM
  • small intestine: 121 nTPM
  • colon: 4.1 nTPM
  • rectum: 3.6 nTPM
  • kidney: 0.9 nTPM
  • smooth muscle: 0.5 nTPM

Single-cell type

  • enterocytes: 326 nCPM
  • colonocytes: 27 nCPM
  • oocytes: 9.2 nCPM
  • goblet cells: 6.4 nCPM
  • enteric transient amplifying cells: 5.8 nCPM
  • enteric stem cells: 2 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

  • amygdala: 0 nTPM
  • basal ganglia: 0 nTPM
  • cerebellum: 0 nTPM
  • cerebral cortex: 0 nTPM
  • choroid plexus: 0 nTPM
  • hippocampal formation: 0 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)
1.49
gnomAD pLI
0
gnomAD missense Z
0.4
DepMap mean gene effect
0.06
DepMap dependency class
none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 2% 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

Antibody and autoantibody relevanceSeroatlas analysis

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

ALPI is annotated at the cell surface, where native ALPI 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 ALPI as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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