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Protein / target

Peptidyl-prolyl cis-trans isomerase A

Encoded byPPIAP62937Homo sapiensSwiss-Prot
Clinically validated
Therapeutic maturity
1
Approved medicines
Open Targets target-level
View by indication →
30
Clinical trials
Small-molecule tractable
Druggability
Structure with Ligand

Protein at a glance

Biological role

Peptidyl-prolyl cis-trans isomerase

Strongest disease association

HIV Infections

Via encoding gene PPIA · Pathway evidence · score 0.60

Therapeutic position

Established drug target

Derived from structured UniProt, Open Targets and literature data on this page.

Protein profile

UniProt 2026_02

Canonical identity and biological annotation from UniProt.

Function overview

Catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides.

View complete UniProt function annotation

Catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides (PubMed:2001362, PubMed:20676357, PubMed:21245143, PubMed:21593166, PubMed:25678563). Exerts a strong chemotactic effect on leukocytes partly through activation of one of its membrane receptors BSG/CD147, initiating a signaling cascade that culminates in MAPK/ERK activation (PubMed:11943775, PubMed:21245143). Activates endothelial cells (ECs) in a pro-inflammatory manner by stimulating activation of NF-kappa-B and ERK, JNK and p38 MAP-kinases and by inducing expression of adhesion molecules including SELE and VCAM1 (PubMed:15130913). Induces apoptosis in ECs by promoting the FOXO1-dependent expression of CCL2 and BCL2L11 which are involved in EC chemotaxis and apoptosis (PubMed:31063815). In response to oxidative stress, initiates proapoptotic and antiapoptotic signaling in ECs via activation of NF-kappa-B and AKT1 and up-regulation of antiapoptotic protein BCL2 (PubMed:23180369). Negatively regulates MAP3K5/ASK1 kinase activity, autophosphorylation and oxidative stress-induced apoptosis mediated by MAP3K5/ASK1 (PubMed:26095851). Necessary for the assembly of TARDBP in heterogeneous nuclear ribonucleoprotein (hnRNP) complexes and regulates TARDBP binding to RNA UG repeats and TARDBP-dependent expression of HDAC6, ATG7 and VCP which are involved in clearance of protein aggregates (PubMed:25678563). Plays an important role in platelet activation and aggregation (By similarity). Regulates calcium mobilization and integrin ITGA2B:ITGB3 bidirectional signaling via increased ROS production as well as by facilitating the interaction between integrin and the cell cytoskeleton (By similarity). Binds heparan sulfate glycosaminoglycans (PubMed:11943775). Inhibits replication of influenza A virus (IAV) (PubMed:19207730). Inhibits ITCH/AIP4-mediated ubiquitination of matrix protein 1 (M1) of IAV by impairing the interaction of ITCH/AIP4 with M1, followed by the suppression of the nuclear export of M1, and finally reduction of the replication of IAV (PubMed:22347431, PubMed:30328013)

Subcellular location

CytoplasmSecretedNucleusCell membrane
Domains and Gene Ontology detail (46)

Domains & features

PPIase cyclophilin-type

Gene Ontology

  • Ccytoplasm
  • Ccytosol
  • Cextracellular exosome
  • Cextracellular region
  • Cextracellular space
  • Cficolin-1-rich granule lumen
  • Cfocal adhesion
  • Cmembrane
  • Cnucleus
  • Cplasma membrane
  • Cprotein-containing complex
  • Csecretory granule lumen

165 aa · 18 kDa · 2 isoforms

Biological roles

What this protein does, drawn together from its UniProt function, Gene Ontology terms and Reactome pathways.

Cell migrationUniProt · GOKinase signallingUniProt · GOHaemostasisUniProt · GO
View supporting evidence

Cell migration

  • ·Catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides (…
  • ·leukocyte chemotaxis
  • ·neutrophil chemotaxis

Kinase signalling

  • ·Catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides (…
  • ·activation of protein kinase B activity
  • ·negative regulation of protein kinase activity

Haemostasis

  • ·Catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides (…
  • ·platelet activation
  • ·platelet aggregation

Concepts derived from UniProt GO Reactome — each badge above shows which sources supported that role.

Approved medicines with mapped indications

1 medicine · 6 areas

Approved therapies targeting this protein, grouped by what they are approved to treat — the disease-first view of the medicines below. Relationships come from the canonical approved-indication graph (ChEMBL phase-4), the same source as the drug cards.

Arthritis, Rheumatoid1 medicine
Eye Diseases1 medicine
Immune System Diseases1 medicine
Inflammation1 medicine
Keratitis1 medicine
Psoriasis1 medicine

Approved indications from ChEMBL (phase-4), via the canonical drug→disease graph.

Drugs targeting this protein

1

How approved and investigational drugs engage this protein — mechanism and action type, direct vs complex targeting, and how broadly each acts across other targets. A drug-first view (the section above groups the approved ones disease-first); direct binders with few recorded targets are listed first.

cyclosporine
Narrow target profileApprovedModulator

Cyclophilin A modulator

Indicated for Arthritis, Rheumatoid, Eye Diseases, Immune System Diseases, Inflammation

Direct interaction with this protein · Only this protein recorded as a target

ChEMBL mechanism, action type, target identity and approved indications. Open Targets clinical status.

Translational evidence

Open Targets 26

Why this target matters therapeutically, strongest evidence first. Disease associations are gene-level (via the gene that encodes this protein) and open into the full confidence synthesis; the development universe, tractability and safety annotations are target-level, from Open Targets.

Strongest disease associations · via encoding gene PPIA

Gene-level evidence surfaced through the gene PPIA that encodes this protein — not a direct protein–disease relationship. Ranked by Forefront's causal-directness weighting, so genetically- and clinically-evidenced diseases lead over ones that merely share the literature.

Psoriasis
0.67Moderately supported

Clinical evidence dominant · Open Targets 0.54

Keratitis
0.65Moderately supported

Clinical evidence dominant · Open Targets 0.53

Graft vs Host Disease
0.60Moderately supported

Clinical evidence dominant · Open Targets 0.46

Arthritis, Rheumatoid
0.59Moderately supported

Clinical evidence dominant · Open Targets 0.46

Eye Diseases
0.54Moderately supported

Clinical evidence dominant · Open Targets 0.44

View evidence synthesis (5)
PsoriasisModerately supported
0.67
agreement 0.510.82
Clinical96%Literature4%

Open Targets aggregate 0.54 · 2 independent evidence families

KeratitisModerately supported
0.65
agreement 0.500.81
Clinical100%Literature0%

Open Targets aggregate 0.53 · 2 independent evidence families

Graft vs Host DiseaseModerately supported
0.60
agreement 0.470.74
Clinical84%Animal model16%

Open Targets aggregate 0.46 · 2 independent evidence families

Arthritis, RheumatoidModerately supported
0.59
agreement 0.430.74
Clinical83%Literature17%

Open Targets aggregate 0.46 · 2 independent evidence families

Eye DiseasesModerately supported
0.54
agreement 0.390.70
Clinical100%Literature0%

Open Targets aggregate 0.44 · 2 independent evidence families

The evidence agreement range shows how closely the independent evidence families agree — it is not a statistical confidence interval, and nothing here is fitted to outcome data. Derived from Open Targets evidence types under Forefront weighting; the per-type scores above show the calculation.

Show all associations
HIV Infections0.60
Psoriasis0.54
Keratitis0.53
Graft vs Host Disease0.46
Arthritis, Rheumatoid0.46
Eye Diseases0.44

Drug development

3 compounds recorded · 1 approved · 2 in clinical development

Open Targets' development universe — every compound recorded against the target at any stage, not all approved medicines. Distinct from the 1 drug that targets this protein in Forefront's canonical graph (1 with a mapped approved indication, shown above): these count different sets and are not a subset relation.

View all recorded compounds (3)
SCY 635Phase 2
CYCLOSPORINEApproval
ALISPORIVIRPhase 3

Open Targets known-drugs universe. Drug name and highest clinical stage only — the disease relationship is NOT read from this slice (it carries trial-context noise); approved indications come from the canonical graph above.

Tractability

Small moleculesEmerging

Feasibility evidence (structure with ligand and high-quality ligand) — no clinical-stage drug of this modality recorded.

AntibodiesEmerging

Feasibility evidence (uniprot loc high conf and go cc high conf) — no clinical-stage drug of this modality recorded.

Protein degradersEmerging

Feasibility evidence (uniprot ubiquitination and database ubiquitination) — no clinical-stage drug of this modality recorded.

Other modalitiesStrong

Approved Drug support this modality.

View underlying tractability evidence (11)
SM · Structure with LigandSM · High-Quality LigandSM · Med-Quality PocketSM · Druggable FamilyAB · UniProt loc high confAB · GO CC high confPR · UniProt UbiquitinationPR · Database UbiquitinationPR · Half-life DataPR · Small Molecule BinderOC · Approved Drug

Raw Open Targets tractability assessment buckets, by modality.

Clinical trials

30

Trials of drugs that target this protein — reached indirectly through those drugs, so a trial listed here studies the drug, not the protein. Ranked by active status, then clinical phase and recency, and spread across the targeting drugs.

View all trials (26)

RECRUITING · via cyclosporine · NCT06658002

RECRUITING · via cyclosporine · NCT00977977

COMPLETED · via cyclosporine · NCT00567983

ClinicalTrials.gov via the drug-target graph.

What's happening now

2

Recent therapeutic activity around this target — regulatory actions, clinical trials and safety signals for a drug that targets this protein, plus publications where such a drug is a genuine subject. Every item is reached indirectly through the drug, not the protein itself; incidental mentions (a paper that merely measures a drug) and press items are excluded.

Objective event titles are shown unmodified; the event kind and significance line are derived from structured fields. Forefront AttentionEvent stream aggregating Europe PMC Regulatory filings ClinicalTrials.gov.