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cystatin 3 (cystatin-C, CST3)
Function:
- inhibitor of cysteine proteinases
- must inhibit protease that hydrolyzes gamma-trace
Structure:
- homodimer
- belongs to the cystatin family
Compartment: secreted
Expression:
- found in various body fluids, including CSF & plasma
- expressed in highest levels in epididymis, vas deferens, brain, thymus, & ovary
- lowest levels in the submandibular gland
- tumor cells secreted cystatin-C
Pathology:
- defects in cystsatin-C (CST3) are a cause of amyloidosis type 6
- potential CSF marker for diagnosis of Creutzfeldt-Jakob disease
- cancer attenuates amyloid pathology in Alzheimer's disease via cystatin-c activation of TREM2 [3]
Laboratory:
- cystatin C in serum/plasma
Related
cystatin C in serum/plasma
cystatin C in urine
General
cystatin
Properties
SIZE: entity length = 146 aa
MW = 16 kD
COMPARTMENT: cerebrospinal fluid
milk
synovial fluid
urine
semen
MOTIF: signal sequence {1-26}
glycine residue {37}
Secondary area of contact {81-85}
cysteine residue {C99}
MODIFICATION: cysteine residue {C109}
cysteine residue {C109}
MODIFICATION: cysteine residue {C99}
cysteine residue {C123}
MODIFICATION: cysteine residue {C143}
cysteine residue {C143}
MODIFICATION: cysteine residue {C123}
SECRETED-BY: fibroblast
neuroglia
INHIBITS: cysteine proteinase
Database Correlations
OMIM correlations
MORBIDMAP 604312
UniProt P01034
Pfam PF00031
Entrez Gene 1471
Kegg hsa:1471
References
- UniProt :accession P01034
- OMIM :accession 105150
- Ledford H
Cancer might protect against Alzheimer's - this protein helps explain why.
Nature News. Jan 22, 2026
https://www.nature.com/articles/d41586-026-00222-7
- Li X, Tang X, Zeng J et al
Peripheral cancer attenuates amyloid pathology in Alzheimer's disease
via cystatin-c activation of TREM2.
Cell. Jan 22, 2026
Not yet indexed in PubMed
https://www.cell.com/cell/abstract/S0092-8674(25)01433-3