PPID
Identifiers
AliasesPPID, CYP-40, CYPD, peptidylprolyl isomerase D
External IDsOMIM: 601753 MGI: 1914988 HomoloGene: 31283 GeneCards: PPID
Orthologs
SpeciesHumanMouse
Entrez

5481

67738

Ensembl

ENSG00000171497

ENSMUSG00000027804

UniProt

Q08752

Q9CR16

RefSeq (mRNA)

NM_005038

NM_026352
NM_001356326

RefSeq (protein)

NP_005029

NP_080628
NP_001343255

Location (UCSC)Chr 4: 158.71 – 158.72 MbChr 3: 79.5 – 79.51 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

Peptidylprolyl isomerase D (cyclophilin D), also known as PPID, is an enzyme which in humans is encoded by the PPID gene on chromosome 4. As a member of the peptidyl-prolyl cis-trans isomerase (PPIase) family, this protein catalyzes the cis-trans isomerization of proline imidic peptide bonds, which allows it to facilitate folding or repair of proteins.[5] In addition, PPID participates in many biological processes, including mitochondrial metabolism, apoptosis, redox, and inflammation, as well as in related diseases and conditions, such as ischemic reperfusion injury, AIDS, and cancer.[6][7][8][9]

Structure

Like other cyclophilins, PPID forms a β-barrel structure with a hydrophobic core. This β-barrel is composed of eight anti-parallel β-strands and capped by two α-helices at the top and bottom. In addition, the β-turns and loops in the strands contribute to the flexibility of the barrel.[8] PPID in particular is composed of 370 residues and shares structural homology with PPIF, FKBP4, and FKBP5, including an N-terminal immunophilin-like domain and a C-terminal tetratricopeptide repeat (TPR) domain.[10]

Function

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.[5] Generally, PPIases are found in all eubacteria and eukaryotes, as well as in a few archaea, and thus are highly conserved.[6][11] The PPIase family is further divided into three structurally distinct subfamilies: cyclophilin (CyP), FK506-binding protein (FKBP), and parvulin (Pvn).[6][8] As a cyclophilin, PPID binds cyclosporin A (CsA) and can be found within the cell or secreted by the cell.[7] In eukaryotes, cyclophilins localize ubiquitously to many cell and tissue types.[7][8] In addition to PPIase and protein chaperone activities, cyclophilins also function in mitochondrial metabolism, apoptosis, immunological response, inflammation, and cell growth and proliferation.[6][7][8] PPID in particular helps chaperone the assembly of heat shock protein Hsp90, as well as the nuclear localization of glucocorticoid, estrogen and progesterone receptors. Along with PPIF, PPID regulates mitochondrial apoptosis. In response to elevated reactive oxygen species (ROS) and calcium ion levels, PPID interacts with Bax to promote mitochondrial pore formation, thus releasing pro-apoptotic factors such as cytochrome C and AIF.[10]

Clinical Significance

As a cyclophilin, PPID binds the immunosuppressive drug CsA to form a CsA-cyclophilin complex, which then targets calcineurin to inhibit the signaling pathway for T-cell activation.

In cardiac myogenic cells, cyclophilins have been observed to be activated by heat shock and hypoxia-reoxygenation as well as complex with heat shock proteins. Thus, cyclophilins may function in cardioprotection during ischemia-reperfusion injury.

Currently, cyclophilin expression is highly correlated with cancer pathogenesis, but the specific mechanisms remain to be elucidated.[7] Studies have shown that PPID protects human keratinocytes from UVA-induced apoptosis, so medication and therapies that inhibit PPID, such as CsA, may inadvertently aid skin cancer development. Conversely, treatments promoting PPID activity may improve patient outcomes when paired with UVA therapies against cancer.[10]

Interactions

PPID has been shown to interact with:

References

  1. 1 2 3 GRCh38: Ensembl release 89: ENSG00000171497 - Ensembl, May 2017
  2. 1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000027804 - Ensembl, May 2017
  3. ↑ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ↑ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. 1 2 "Entrez Gene: PPID peptidylprolyl isomerase D (cyclophilin D)".
  6. 1 2 3 4 Kazui T, Inoue N, Yamada O, Komatsu S (Jan 1992). "Selective cerebral perfusion during operation for aneurysms of the aortic arch: a reassessment". The Annals of Thoracic Surgery. 53 (1): 109–14. doi:10.1016/0003-4975(92)90767-x. PMID 1530810.
  7. 1 2 3 4 5 6 Yao Q, Li M, Yang H, Chai H, Fisher W, Chen C (Mar 2005). "Roles of cyclophilins in cancers and other organ systems". World Journal of Surgery. 29 (3): 276–80. doi:10.1007/s00268-004-7812-7. PMID 15706440. S2CID 11678319.
  8. 1 2 3 4 5 Wang T, Yun CH, Gu SY, Chang WR, Liang DC (Aug 2005). "1.88 A crystal structure of the C domain of hCyP33: a novel domain of peptidyl-prolyl cis-trans isomerase". Biochemical and Biophysical Research Communications. 333 (3): 845–9. doi:10.1016/j.bbrc.2005.06.006. PMID 15963461.
  9. ↑ Stocki P, Chapman DC, Beach LA, Williams DB (Aug 2014). "Depletion of cyclophilins B and C leads to dysregulation of endoplasmic reticulum redox homeostasis". The Journal of Biological Chemistry. 289 (33): 23086–96. doi:10.1074/jbc.M114.570911. PMC 4132807. PMID 24990953.
  10. 1 2 3 4 Jandova J, Janda J, Sligh JE (Mar 2013). "Cyclophilin 40 alters UVA-induced apoptosis and mitochondrial ROS generation in keratinocytes". Experimental Cell Research. 319 (5): 750–60. doi:10.1016/j.yexcr.2012.11.016. PMC 3577976. PMID 23220213.
  11. ↑ Hoffmann H, Schiene-Fischer C (Jul 2014). "Functional aspects of extracellular cyclophilins". Biological Chemistry. 395 (7–8): 721–35. doi:10.1515/hsz-2014-0125. PMID 24713575. S2CID 32395688.

Further reading

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