PPIB Gene: Peptidylprolyl Isomerase B (Cyclophilin B)
A comprehensive biomedical resource for PPIB, including genomic data, expression, mutations, and associated diseases.
Gene Information Card
| Symbol | PPIB |
|---|---|
| Full Name | Peptidylprolyl Isomerase B |
| Gene Type | Protein coding |
| Chromosomal Location | 15q22.31 |
| NCBI Gene ID | 5479 ncbi.nlm.nih.gov/gene/5479 |
| Ensembl ID | ENSG00000166794 |
| UniProt ID | P23284 |
| OMIM ID | 123841 |
| HGNC ID | 9255 |
| Aliases | CYPB, SCYLP, OI9 |
Description
PPIB encodes cyclophilin B, a member of the peptidyl-prolyl cis-trans isomerase (PPIase) family. This enzyme catalyzes the isomerization of proline imidic peptide bonds, a rate-limiting step in protein folding. Cyclophilin B is a cyclosporine-binding protein and is involved in immunosuppression, protein trafficking, and collagen maturation. Mutations in PPIB are associated with osteogenesis imperfecta type IX.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Osteogenesis Imperfecta Type IX | Mutations in PPIB disrupt cyclophilin B function, impairing proper folding and secretion of type I procollagen, leading to brittle bones. | OMIM #259440; PMID: 19293843 |
| Immunosuppression (Cyclosporine A binding) | Cyclophilin B binds cyclosporine A, forming a complex that inhibits calcineurin, thereby blocking T-cell activation. | UniProt P23284; PMID: 10659856 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 22.1 | Medium |
| Kidney | 18.5 | Medium |
| Heart | 15.3 | Medium |
| Brain | 12.8 | Medium |
| Lung | 11.4 | Medium |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 | 22.5 | Hepatocellular carcinoma cell line |
| HEK 293 | 19.8 | Embryonic kidney cells |
| K-562 | 16.2 | Chronic myelogenous leukemia |
| A549 | 14.7 | Lung carcinoma |
| MCF7 | 13.1 | Breast adenocarcinoma |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.178G>A (p.Gly60Arg) | Missense | <0.01% | Loss of PPIase activity; associated with OI type IX |
| c.442C>T (p.Arg148*) | Nonsense | <0.01% | Premature truncation; loss of function |
| c.1A>G (p.Met1?) | Start loss | <0.01% | No protein production |
Mutation functional classification
Loss of Function (LOF)
Missense, nonsense, and start-loss mutations in PPIB lead to reduced or absent cyclophilin B activity, impairing collagen folding and causing osteogenesis imperfecta type IX.
Gain of Function (GOF)
No gain-of-function mutations are currently reported for PPIB.
Dominant Negative (DN)
No dominant-negative mutations are currently reported for PPIB.
View complete mutation data：
Gene Ontology (GO)
| • peptidyl-prolyl cis-trans isomerase activity (GO:0003755) | • protein folding (GO:0006457) |
| • protein binding (GO:0005515) | • cytoplasm (GO:0005737) |
| • endoplasmic reticulum (GO:0005783) |
Pathways
• Protein folding and processing in endoplasmic reticulum
• Immunosuppressive action of cyclosporine A
Protein Summary
Cyclophilin B (CYPB) is a 21.4 kDa protein localized primarily to the endoplasmic reticulum. It possesses peptidyl-prolyl cis-trans isomerase activity essential for the proper folding of proline-containing proteins, particularly collagens. CYPB also functions as a chaperone and is a target of the immunosuppressive drug cyclosporine A. Its role in collagen maturation links it directly to osteogenesis imperfecta.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| PPIB Knockout HEK293 Cell Line | EDJ-KQ3788 | Human | 5479 | Details Get a Quote |
| PPIB Knockout A-549 Cell Line | EDJ-KQ25890 | Human | 5479 | Details Get a Quote |
| PPIB Knockout HCT 116 Cell Line | EDJ-KQ25891 | Human | 5479 | Details Get a Quote |
| PPIB Knockout HeLa Cell Line | EDJ-KQ25892 | Human | 5479 | Details Get a Quote |
