Cystatin C
Cystatin C is a secreted cysteine proteinase inhibitor of the type 2 cystatin group, encoded by the CST3 gene. It is thought to act as a local regulator of cysteine protease activity and is the most abundant extracellular inhibitor of this enzyme class. Browse Assay Genie's current range of Cystatin C research reagents below, or read on for the biology behind the target.
Cystatin C is an inhibitor of cysteine proteinases. It is thought to serve an important physiological role as a local regulator of this enzyme activity. According to the NCBI Gene summary, it is the most abundant extracellular inhibitor of cysteine proteases, found in high concentrations in biological fluids and expressed in virtually all organs of the body. Type 2 cystatins as a class are found in a variety of human fluids and secretions, where they appear to provide protective functions. Cystatin C has also been shown to have an antimicrobial function, inhibiting the replication of herpes simplex virus.
The CST3 gene sits in the cystatin locus on chromosome 20, which contains the majority of the type 2 cystatin genes and pseudogenes. Alternative splicing produces multiple transcript variants that all encode a single protein. The protein belongs to the cystatin family, and HGNC places it in the type 2 cystatins gene group. The wider cystatin superfamily contains proteins with multiple cystatin-like sequences. Some members are active cysteine protease inhibitors, while others have lost, or perhaps never acquired, this activity. Three inhibitory families make up the superfamily: the type 1 cystatins (stefins), the type 2 cystatins and the kininogens.
Cystatin C has disease relevance in vascular biology. A mutation in the gene has been associated with amyloid angiopathy, and the earlier HGNC name for the gene, cystatin C (amyloid angiopathy and cerebral hemorrhage), reflects this link. Expression of the protein in vascular wall smooth muscle cells is severely reduced in both atherosclerotic and aneurysmal aortic lesions, which establishes its role in vascular disease. Mouse and rat each have a Cst3 ortholog, so the protein can be studied in common rodent models.
Cystatin C is thought to act as a local regulator of cysteine proteinase activity, making it a key subject for studies of extracellular protease control.
Its expression in vascular wall smooth muscle cells is severely reduced in atherosclerotic and aneurysmal aortic lesions, establishing a role in vascular disease.
A mutation in the CST3 gene has been associated with amyloid angiopathy, linking the protein to cerebral vascular pathology.
Cystatin C has an antimicrobial function and has been shown to inhibit the replication of herpes simplex virus.
Cystatin C inhibits cysteine proteinases and is thought to serve as a local regulator of their activity. It is the most abundant extracellular inhibitor of cysteine proteases, found in high concentrations in biological fluids. It also inhibits herpes simplex virus replication.
Cystatin C is the protein name and CST3 is the gene symbol approved by HGNC. The gene was formerly named cystatin C (amyloid angiopathy and cerebral hemorrhage). Alternative splicing gives multiple transcript variants, but they all encode a single protein.
A CST3 mutation has been associated with amyloid angiopathy, and reduced expression in vascular smooth muscle is seen in atherosclerotic and aneurysmal aortic lesions. Mouse and rat both carry a Cst3 ortholog; check the datasheet of any product for its validated reactivity.
Other type 1 and type 2 cystatin family members and related cysteine protease inhibitors with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P01034; product specifications from Assay Genie datasheets.