CST5 (Cystatin D)
A member of the cystatin superfamily involved in protease inhibition and potential tumor suppression
Gene Information Card
| Symbol | CST5 |
|---|---|
| Full Name | Cystatin D |
| Gene Type | protein-coding |
| Chromosomal Location | 20p11.21 |
| NCBI Gene ID | 1473 ncbi.nlm.nih.gov/gene/1473 |
| Ensembl ID | ENSG00000101439 |
| UniProt ID | P28325 |
| OMIM ID | 123857 |
| HGNC ID | 2476 |
| Aliases | cystatin D, CSTD |
Description
CST5 encodes cystatin D, a member of the type 2 cystatin family of cysteine protease inhibitors. The protein is secreted and functions as a potent inhibitor of cathepsins (e.g., cathepsin L, S, and H). It is primarily expressed in salivary glands, pancreas, and other exocrine tissues. CST5 has been implicated in tumor suppression, particularly in colorectal and pancreatic cancers, where its expression is often downregulated. The gene spans approximately 4.5 kb on chromosome 20p11.21 and contains 3 exons.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Colorectal Cancer | Loss of CST5 expression leads to increased cathepsin activity, promoting invasion and metastasis | PMID: 23431129 |
| Pancreatic Cancer | Epigenetic silencing of CST5 contributes to tumor progression | PMID: 25656894 |
| Salivary Gland Tumors | Reduced cystatin D levels correlate with malignant transformation | PMID: 17334994 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Salivary gland | 112.3 | High |
| Pancreas | 45.6 | Medium |
| Kidney | 12.1 | Low |
| Liver | 3.4 | Not detected |
| Lung | 1.2 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 0.8 | Low expression |
| HCT116 | 2.1 | Moderate expression |
| PANC-1 | 0.3 | Very low expression |
| MCF7 | 1.5 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | missense | <0.01% | Potential loss of start codon |
| c.148C>T (p.Arg50Cys) | missense | <0.01% | Alters conserved residue in cystatin domain |
| c.256G>A (p.Gly86Ser) | missense | <0.01% | Unknown functional impact |
Mutation functional classification
Loss of Function (LOF)
Mutations affecting the start codon or conserved cystatin domain residues likely impair protease inhibitory activity.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
No dominant-negative mutations described.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Cysteine protease inhibition (cathepsin L
• S
• H)
• Tumor suppressor pathway in colorectal cancer
Protein Summary
Cystatin D is a 142-amino acid secreted protein (16.2 kDa) containing a signal peptide (residues 1-20) and a single cystatin domain. It inhibits papain-like cysteine proteases, particularly cathepsin L (Ki ~0.5 nM) and cathepsin S. The protein is glycosylated and forms dimers under reducing conditions. Its expression is regulated by promoter methylation in cancer.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CST5 Knockout HEK293 Cell Line | EDJ-KQ4373 | Human | 1473 | Details Get a Quote |
| CST5 Knockout HeLa Cell Line | EDJ-KQ77843 | Human | 1473 | Details Get a Quote |
| CST5 Knockout A-549 Cell Line | EDJ-KQ77844 | Human | 1473 | Details Get a Quote |
| CST5 Knockout HCT 116 Cell Line | EDJ-KQ77845 | Human | 1473 | Details Get a Quote |
