Peptidyl-prolyl cis-trans isomerase H (PPIH)
The protein contains 177 amino acids for an estimated molecular weight of 19208 Da.
PPIase that catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides and may therefore assist protein folding (PubMed:20676357). Participates in pre-mRNA splicing. May play a role in the assembly of the U4/U5/U6 tri-snRNP complex, one of the building blocks of the spliceosome. May act as a chaperone. (updated: Oct. 10, 2018)
Protein identification was indicated in the following studies:
- Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
- D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
Methods
The following articles were analysed to gather the proteome content of erythrocytes.
The gene or protein list provided in the studies were processed using the ID mapping API of Uniprot in September 2018. The number of proteins identified and mapped without ambiguity in these studies is indicated below.
Only Swiss-Prot entries (reviewed) were considered for protein evidence assignation.
| Publication | Identification 1 | Uniprot mapping 2 | Not mapped / Obsolete | TrEMBL | Swiss-Prot |
|---|---|---|---|---|---|
| Goodman (2013) | 2289 (gene list) | 2278 | 53 | 20599 | 2269 |
| Lange (2014) | 1234 | 1234 | 7 | 28 | 1224 |
| Hegedus (2015) | 2638 | 2622 | 0 | 235 | 2387 |
| Wilson (2016) | 1658 | 1528 | 170 | 291 | 1068 |
| d'Alessandro (2017) | 1826 | 1817 | 2 | 0 | 1815 |
| Bryk (2017) | 2090 | 2060 | 10 | 108 | 1942 |
| Chu (2018) | 1853 | 1804 | 55 | 362 | 1387 |
1 as available in the article and/or in supplementary material
2 uniprot mapping returns all protein isoforms as one entry
The compilation of older studies can be retrieved from the Red Blood Cell Collection database.
The data and differentiation stages presented below come from the proteomic study and analysis performed by our partners of the GReX consortium, more details are available in their published work.
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Biological Process
Angiogenesis
MRNA splicing, via spliceosome
Positive regulation of viral genome replication
Protein folding
Protein peptidyl-prolyl isomerization
Protein refolding
Protein-containing complex assembly
The reference OMIM entry for this protein is 606095
Peptidyl-prolyl isomerase h; ppih
Cyclophilin h
Cyclophilins catalyze the cis-trans isomerization of peptidyl-prolyl bonds, a rate-limiting step in protein folding. Members of the cyclophilin family bind the immunosuppressive drug cyclosporin A (CsA) and share a conserved core domain of approximately 110 amino acids, called the cyclophilin domain.
CLONING
During purification of a 55-kD protein associated with U4/U6 and U4/U6.U5 snRNPs, Horowitz et al. (1997) copurified an 18-kD protein. By database searching, they identified the protein as a novel human cyclophilin, PPIH, which they named USA-CyP (U-snRNP-associated cyclophilin). Independently, Teigelkamp et al. (1998) purified PPIH, which they called SnuCyp-20, as a 20-kD component of the spliceosomal 25S [U4/U6.U5] tri-snRNP complex from HeLa cells. PPIH encodes a deduced 177-amino acid protein that shares 68% and 55% sequence identity with C. elegans CyP-11 and human cyclophilin A (PPIA; 123840), respectively. Teigelkamp et al. (1998) demonstrated that purified tri-snRNPs exhibit peptidyl-prolyl cis/trans isomerase activity in vitro, which is CsA-sensitive, suggesting that PPIH is an active isomerase. Reidt et al. (2000) determined the crystal structure of PPIH, which resembles that of PPIA. The active centers of PPIH and PPIA, as well as most residues involved in PPIA/CsA binding, superimpose almost perfectly. Using immunofluorescence microscopy, Teigelkamp et al. (1998) demonstrated that PPIH colocalizes with snRNP-containing structures known as nuclear speckles. Horowitz et al. (1997) demonstrated that PPIH forms a stable complex with PRP3 (607301) and PRP4 (607795) in the absence of RNA. Using fractionation of RNA-free protein complexes dissociated from isolated tri-snRNPs, Teigelkamp et al. (1998) determined that PPIH is part of a stable heteromer containing the U4/U6-specific 60-kD (PRP4) and 90-kD (PRP3) proteins. Using coimmunoprecipitation experiments, they demonstrated that PPIH specifically interacts with the [U4/U6.U5] tri-snRNP complex 60-kD component. Teigelkamp et al. (1998) concluded that PPIH may play a role in the assembly of the tri-snRNP complex and/or the spliceosome.MAPPING
The International Radiation Hybrid Mapping Consortium mapped the PPIH gene to chromosome 11 (TMAP sts-AA025365). ... More on the omim web site
Oct. 20, 2018: Protein entry updated
Automatic update: OMIM entry 606095 was added.
Oct. 19, 2018: Additional information
Initial protein addition to the database. This entry was referenced in Bryk and co-workers. (2017).