Seroatlas · Human Serome Atlas

PPID

Peptidyl-prolyl cis-trans isomerase D

Also known as: CYP-40, CypD, PPID_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
Q08752
Gene
PPID
Ensembl
ENSG00000171497
Chromosome
4
Canonical length
370 aa
Protein class
Enzymes, Metabolic proteins, Plasma proteins, Predicted intracellular proteins
Subcellular location
Nucleoplasm,Nucleoli,Nucleoli rim,Primary cilium,Cytosol
Quaternary structure
Homodimer

OverviewNCBI Gene

The protein encoded by this gene is a member of the peptidyl-prolyl cis-trans isomerase (PPIase) family. PPIases catalyze the cis-trans isomerization of proline imidic peptide bonds in oligopeptides and accelerate the folding of proteins. This protein has been shown to possess PPIase activity and, similar to other family members, can bind to the immunosuppressant cyclosporin A. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

370 residues, UniProt reviewed canonical sequence.

>Q08752|PPID
     1  MSHPSPQAKP SNPSNPRVFF DVDIGGERVG RIVLELFADI VPKTAENFRA LCTGEKGIGH
    61  TTGKPLHFKG CPFHRIIKKF MIQGGDFSNQ NGTGGESIYG EKFEDENFHY KHDREGLLSM
   121  ANAGRNTNGS QFFITTVPTP HLDGKHVVFG QVIKGIGVAR ILENVEVKGE KPAKLCVIAE
   181  CGELKEGDDG GIFPKDGSGD SHPDFPEDAD IDLKDVDKIL LITEDLKNIG NTFFKSQNWE
   241  MAIKKYAEVL RYVDSSKAVI ETADRAKLQP IALSCVLNIG ACKLKMSNWQ GAIDSCLEAL
   301  ELDPSNTKAL YRRAQGWQGL KEYDQALADL KKAQGIAPED KAIQAELLKV KQKIKAQKDK
   361  EKAVYAKMFA

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against PPID 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)
0.25
Highest tissue expression
68 nTPM

Expression across tissuesHPA

Tissue

  • skeletal muscle: 68 nTPM
  • liver: 56 nTPM
  • tongue: 42 nTPM
  • heart muscle: 34 nTPM
  • cerebral cortex: 31 nTPM
  • cerebellum: 29 nTPM

Single-cell type

  • early primary spermatocytes: 92 nCPM
  • retinal horizontal cells: 86 nCPM
  • differentiating spermatogonia: 85 nCPM
  • endometrial ciliated cells: 81 nCPM
  • late primary spermatocytes: 81 nCPM
  • fallopian tube ciliated cells: 78 nCPM

Immune cell

  • basophil: 69 nTPM
  • eosinophil: 53 nTPM
  • NK-cell: 40 nTPM
  • T-reg: 36 nTPM
  • non-classical monocyte: 36 nTPM
  • MAIT T-cell: 35 nTPM

Brain region

  • hypothalamus: 36 nTPM
  • white matter: 34 nTPM
  • choroid plexus: 33 nTPM
  • cerebral cortex: 28 nTPM
  • pons: 28 nTPM
  • thalamus: 28 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)
1.17
gnomAD pLI
0
gnomAD missense Z
0.61
DepMap mean gene effect
0.06
DepMap dependency class
none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% 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 PPID 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 PPID as an antibody target. Whether an autoantibody or antibody against PPID could matter depends on whether native PPID is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

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

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