CST1
CST1 (cystatin SN) is a secreted type 2 cystatin that inhibits cysteine proteinases. It is found in saliva, tears, urine and seminal fluid, where type 2 cystatins appear to provide protective functions. Browse Assay Genie's current range of CST1 research reagents below, or read on for the biology behind the target.
CST1, also called cystatin SN, is a cysteine proteinase inhibitor. Human saliva appears to contain several cysteine proteinase inhibitors that are immunologically related to cystatin S but differ in specificity because of amino acid sequence differences. Cystatin SN has a pI of 7.5 and is a much better inhibitor of papain and dipeptidyl peptidase I than cystatin S, although both inhibit ficin equally well.
The CST1 gene sits in the cystatin locus on chromosome 20, which contains the majority of the type 2 cystatin genes and pseudogenes. The encoded protein is secreted and is found in saliva, tears, urine and seminal fluid. The HGNC places it in the gene group of type 2 cystatins, and UniProt assigns it to the cystatin family. Researchers working with the CST1 protein often study it alongside neighbouring cystatin genes such as CST2 and CST4.
The cystatin superfamily encompasses proteins that contain multiple cystatin-like sequences. Some members are active cysteine protease inhibitors, while others have lost, or perhaps never acquired, this activity. The superfamily has three inhibitory families: the type 1 cystatins (stefins), the type 2 cystatins and the kininogens. Type 2 cystatins are found in a variety of human fluids and secretions, where they appear to provide protective functions.
Cystatin SN inhibits papain and dipeptidyl peptidase I more effectively than cystatin S, making it a useful subject for studying inhibitor specificity.
CST1 is found in saliva, tears, urine and seminal fluid, supporting studies of secreted protective proteins in human fluids.
Type 2 cystatins differ in specificity through sequence variation, so CST1 is relevant to comparing active and inactive members of the superfamily.
The CST1 gene lies in the chromosome 20 cystatin locus, which holds most type 2 cystatin genes and pseudogenes.
CST1 encodes cystatin SN, a secreted cysteine proteinase inhibitor. It inhibits papain and dipeptidyl peptidase I much better than cystatin S does, and inhibits ficin equally well. Type 2 cystatins such as this one appear to provide protective functions in human fluids and secretions.
The HGNC full name is cystatin SN, and UniProt lists the protein as Cystatin-SN. No alternative gene symbols or previous names are recorded. It is distinct from cystatin S, a related salivary inhibitor that differs in specificity because of amino acid sequence differences.
Yes. CST1 belongs to the cystatin family and to the type 2 cystatins gene group. The cystatin superfamily also includes type 1 cystatins (stefins) and kininogens. Most type 2 cystatin genes cluster in the chromosome 20 cystatin locus, where CST1 is located.
Other cystatin family members, including type 2 cystatins from the chromosome 20 locus and related cysteine protease inhibitors.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P01037; product specifications from Assay Genie datasheets.