CST3 (Cystatin C) Gene
A key regulator of cysteine protease activity, implicated in neurodegeneration, cardiovascular disease, and cancer
Gene Information Card
| Symbol | CST3 |
|---|---|
| Full Name | Cystatin C |
| Gene Type | Protein coding |
| Chromosomal Location | 20p11.21 |
| NCBI Gene ID | 1471 ncbi.nlm.nih.gov/gene/1471 |
| Ensembl ID | ENSG00000101439 |
| UniProt ID | P01034 |
| OMIM ID | 604312 |
| HGNC ID | 2475 |
| Aliases | ARMD11, HEL-S-2, MGC117328 |
Description
CST3 encodes cystatin C, a potent inhibitor of cysteine proteases (cathepsins). It is secreted in body fluids and plays roles in proteolytic regulation, amyloid fibril formation, and neuroprotection. Mutations are linked to hereditary cerebral amyloid angiopathy (HCCAA) and Alzheimer disease risk.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Hereditary cerebral hemorrhage with amyloidosis (HCCAA) | Missense mutation (L68Q) causes amyloid deposition in cerebral vessels | OMIM #105150 |
| Alzheimer disease | CST3 variants (e.g., rs1064039) modulate amyloid-beta aggregation and clearance | ClinVar, NCBI |
| Age-related macular degeneration | CST3 expression in drusen; potential role in complement and protease imbalance | OMIM #603075 |
| Aortic aneurysm | Cystatin C deficiency leads to increased cathepsin activity and elastin degradation | NCBI Gene, PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 12.5 | High |
| Liver | 8.2 | Medium |
| Kidney | 15.1 | High |
| Pancreas | 6.4 | Medium |
| Lung | 4.3 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 14.0 | High expression |
| HepG2 | 9.5 | Medium expression |
| SH-SY5Y | 11.2 | High expression |
| A549 | 5.1 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| L68Q (c.205T>A) | Missense | Rare | Amyloidogenic; causes HCCAA |
| rs1064039 (A25T) | Missense | Common (allele freq ~0.2) | Modifies Alzheimer disease risk |
| c.148G>A (V50I) | Missense | Rare | Reduced inhibitory activity |
Mutation functional classification
Loss of Function (LOF)
L68Q leads to misfolding and loss of protease inhibition, promoting amyloid deposition.
Gain of Function (GOF)
Not reported for CST3.
Dominant Negative (DN)
L68Q mutant forms dimers that sequester wild-type cystatin C, reducing overall activity.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Amyloid fiber formation (Reactome: R-HSA-977225)
• Cysteine protease inhibition (UniProt)
Protein Summary
Cystatin C is a 13.3 kDa secreted protein composed of 120 amino acids. It inhibits cathepsins B, H, K, L, and S. The protein is a component of the amyloid deposits in cerebral amyloid angiopathy and is used as a biomarker for kidney function. Its structure includes a conserved cystatin domain with a central alpha-helix and beta-sheet.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CST3 Knockout HEK293 Cell Line | EDJ-KQ3644 | Human | 1471 | Details Get a Quote |
| CST3 Knockout A-549 Cell Line | EDJ-KQ26881 | Human | 1471 | Details Get a Quote |
| CST3 Knockout HCT 116 Cell Line | EDJ-KQ26882 | Human | 1471 | Details Get a Quote |
| CST3 Knockout HeLa Cell Line | EDJ-KQ26883 | Human | 1471 | Details Get a Quote |
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