Cystatin-S is a protein that in humans is encoded by the CST4gene.[3][4]
The cystatin superfamily encompasses proteins that contain multiple cystatin-like sequences. Some of the members are active cysteine protease inhibitors, while others have lost or perhaps never acquired this inhibitory activity. There are three inhibitory families in the superfamily, including the type 1 cystatins (stefins), type 2 cystatins and the kininogens. The type 2 cystatin proteins are a class of cysteine proteinase inhibitors found in a variety of human fluids and secretions. The cystatin locus on chromosome 20 contains the majority of the type 2 cystatin genes and pseudogenes. This gene is located in the cystatin locus and encodes a type 2 salivary cysteine peptidase inhibitor. The protein is an S-type cystatin, based on its high level of expression in saliva, tears and seminal plasma. The specific role in these fluids is unclear but antibacterial and antiviral activity is present, consistent with a protective function.[4]
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^Saitoh E, Isemura S, Sanada K, Ohnishi K (Apr 1992). "The human cystatin gene family: cloning of three members and evolutionary relationship between cystatins and Bowman-Birk type proteinase inhibitors". Biomed Biochim Acta. 50 (4–6): 599–605. PMID1801729.
Saitoh E, Isemura S, Sanada K, Ohnishi K (1993). "Characterization of Two Members(CST4 and CST5) of the Cystatin Gene Family and Molecular Evolution of Cystatin Genes". Recent Progress on Kinins. Vol. 38. pp. 340–8. doi:10.1007/978-3-0348-7321-5_43 (inactive 1 November 2024). ISBN978-3-0348-7323-9. PMID1334620. {{cite book}}: |journal= ignored (help)CS1 maint: DOI inactive as of November 2024 (link)
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Isemura S, Saitoh E, Sanada K, Minakata K (1992). "Identification of full-sized forms of salivary (S-type) cystatins (cystatin SN, cystatin SA, cystatin S, and two phosphorylated forms of cystatin S) in human whole saliva and determination of phosphorylation sites of cystatin S". J. Biochem. 110 (4): 648–54. doi:10.1093/oxfordjournals.jbchem.a123634. PMID1778989.
Saitoh E, Isemura S, Sanada K, et al. (1989). "Cystatin superfamily. Evidence that family II cystatin genes are evolutionarily related to family III cystatin genes". Biol. Chem. Hoppe-Seyler. 369 Suppl: 191–7. PMID3202964.
Hawke DH, Yuan PM, Wilson KJ, Hunkapiller MW (1987). "Identification of a long form of cystatin from human saliva by rapid microbore HPLC mapping". Biochem. Biophys. Res. Commun. 145 (3): 1248–53. doi:10.1016/0006-291X(87)91571-3. PMID3496880.
Isemura S, Saitoh E, Sanada K (1985). "Isolation and amino acid sequence of SAP-1, an acidic protein of human whole saliva, and sequence homology with human gamma-trace". J. Biochem. 96 (2): 489–98. doi:10.1093/oxfordjournals.jbchem.a134861. PMID6501254.
Dickinson DP, Thiesse M, Dempsey LD, Millar SJ (1993). "Genomic cloning, physical mapping, and expression of human type 2 cystatin genes". Crit. Rev. Oral Biol. Med. 4 (3–4): 573–80. doi:10.1177/10454411930040034401. PMID7690606.
Dickinson DP, Zhao Y, Thiesse M, Siciliano MJ (1995). "Direct mapping of seven genes encoding human type 2 cystatins to a single site located at 20p11.2". Genomics. 24 (1): 172–5. doi:10.1006/geno.1994.1595. PMID7896273.
Thiesse M, Millar SJ, Dickinson DP (1994). "The human type 2 cystatin gene family consists of eight to nine members, with at least seven genes clustered at a single locus on human chromosome 20". DNA Cell Biol. 13 (2): 97–116. doi:10.1089/dna.1994.13.97. PMID8179826.
Henskens YM, van den Keijbus PA, Veerman EC, et al. (1996). "Protein composition of whole and parotid saliva in healthy and periodontitis subjects. Determination of cystatins, albumin, amylase and IgA". Journal of Periodontal Research. 31 (1): 57–65. doi:10.1111/j.1600-0765.1996.tb00464.x. PMID8636877.
Baron A, DeCarlo A, Featherstone J (2000). "Functional aspects of the human salivary cystatins in the oral environment". Oral Diseases. 5 (3): 234–40. doi:10.1111/j.1601-0825.1999.tb00307.x. PMID10483070.