Seroatlas · Human Serome Atlas

PDIA4

Protein disulfide-isomerase A4

Also known as: ERP70, ERP72, PDIA4_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
P13667
Gene
PDIA4
Ensembl
ENSG00000155660
Chromosome
7
Canonical length
645 aa
Protein class
Enzymes, Metabolic proteins, Plasma proteins, Predicted intracellular proteins
Subcellular location
Endoplasmic reticulum
Secretome location
Intracellular and membrane

OverviewNCBI Gene

This gene encodes a member of the disulfide isomerase (PDI) family of endoplasmic reticulum (ER) proteins that catalyze protein folding and thiol-disulfide interchange reactions. The encoded protein has an N-terminal ER-signal sequence, three catalytically active thioredoxin (TRX) domains, two TRX-like domains and a C-terminal ER-retention sequence. This protein, when bound to cyclophilin B, enhances the rate of immunoglobulin G intermolecular disulfide bonding and antibody assembly. [provided by RefSeq, Dec 2016]

Canonical amino-acid sequenceUniProt

645 residues, UniProt reviewed canonical sequence.

>P13667|PDIA4
     1  MRPRKAFLLL LLLGLVQLLA VAGAEGPDED SSNRENAIED EEEEEEEDDD EEEDDLEVKE
    61  ENGVLVLNDA NFDNFVADKD TVLLEFYAPW CGHCKQFAPE YEKIANILKD KDPPIPVAKI
   121  DATSASVLAS RFDVSGYPTI KILKKGQAVD YEGSRTQEEI VAKVREVSQP DWTPPPEVTL
   181  VLTKENFDEV VNDADIILVE FYAPWCGHCK KLAPEYEKAA KELSKRSPPI PLAKVDATAE
   241  TDLAKRFDVS GYPTLKIFRK GRPYDYNGPR EKYGIVDYMI EQSGPPSKEI LTLKQVQEFL
   301  KDGDDVIIIG VFKGESDPAY QQYQDAANNL REDYKFHHTF STEIAKFLKV SQGQLVVMQP
   361  EKFQSKYEPR SHMMDVQGST QDSAIKDFVL KYALPLVGHR KVSNDAKRYT RRPLVVVYYS
   421  VDFSFDYRAA TQFWRSKVLE VAKDFPEYTF AIADEEDYAG EVKDLGLSES GEDVNAAILD
   481  ESGKKFAMEP EEFDSDTLRE FVTAFKKGKL KPVIKSQPVP KNNKGPVKVV VGKTFDSIVM
   541  DPKKDVLIEF YAPWCGHCKQ LEPVYNSLAK KYKGQKGLVI AKMDATANDV PSDRYKVEGF
   601  PTIYFAPSGD KKNPVKFEGG DRDLEHLSKF IEEHATKLSR TKEEL

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against PDIA4 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
235 nTPM

Expression across tissuesHPA

Tissue

  • liver: 235 nTPM
  • thyroid gland: 221 nTPM
  • epididymis: 155 nTPM
  • pancreas: 116 nTPM
  • stomach: 90 nTPM
  • cervix: 88 nTPM

Single-cell type

  • epididymal principal cells: 781 nCPM
  • hepatocytes: 653 nCPM
  • extravillous trophoblasts: 538 nCPM
  • plasma cells: 448 nCPM
  • syncytiotrophoblasts: 268 nCPM
  • prostatic glandular cells: 254 nCPM

Immune cell

  • plasmacytoid DC: 252 nTPM
  • total PBMC: 161 nTPM
  • MAIT T-cell: 136 nTPM
  • gdT-cell: 131 nTPM
  • memory CD8 T-cell: 100 nTPM
  • memory B-cell: 100 nTPM

Brain region

  • white matter: 82 nTPM
  • medulla oblongata: 59 nTPM
  • thalamus: 56 nTPM
  • choroid plexus: 54 nTPM
  • hypothalamus: 49 nTPM
  • cerebellum: 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)
0.51
gnomAD pLI
0.08
gnomAD missense Z
-0.13
DepMap mean gene effect
-0.03
DepMap dependency class
none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 8% 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 PDIA4 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 PDIA4 as an antibody target. Whether an autoantibody or antibody against PDIA4 could matter depends on whether native PDIA4 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

PDIA4 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.

Source-annotated serology context

The source annotations explicitly mention antibody, autoantibody, autoantigen, or autoimmune context. This is biological context, not study-specific reactivity.

  • This protein, when bound to cyclophilin B, enhances the rate of immunoglobulin G intermolecular disulfide bonding and antibody assembly.

Canonical record: https://seroatlas.com/gene/PDIA4. 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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