CST2 explained

Cystatin-SA is a protein that in humans is encoded by the CST2 gene.^[1]

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, where they appear to provide protective functions. 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 secreted thiol protease inhibitor found at high levels in saliva, tears and seminal plasma.

External links

• The MEROPS online database for peptidases and their inhibitors: I25.009

Further reading

• Brown WM, Dziegielewska KM . Friends and relations of the cystatin superfamily--new members and their evolution . Protein Sci. . 6 . 1 . 5–12 . 1997 . 9007972 . 10.1002/pro.5560060102 . 2143511 .
• Abrahamson M, Jonsdottir S, Olafsson I . Hereditary cystatin C amyloid angiopathy: identification of the disease-causing mutation and specific diagnosis by polymerase chain reaction based analysis . Hum. Genet. . 89 . 4 . 377–80 . 1992 . 1352269 . 10.1007/BF00194306 . 24226058 . etal.
• Takahashi M, Honda Y, Ogawa K, Barka T . Immunofluorescence localization of cystatins in human lacrimal gland and in the exorbital lacrimal gland of the rat . Acta Ophthalmologica . 70 . 5 . 625–31 . 1993 . 1471486 . 10.1111/j.1755-3768.1992.tb02143.x . 30180390 .
• Isemura S, Saitoh E, Sanada K, Minakata K . 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 . 1992 . 1778989 . 10.1093/oxfordjournals.jbchem.a123634.
• Bobek LA, Aguirre A, Levine MJ . Human salivary cystatin S. Cloning, sequence analysis, hybridization in situ and immunocytochemistry . Biochem. J. . 278 . 3. 627–35 . 1991 . 1898352 . 10.1042/bj2780627. 1151393 .
• Abrahamson M, Olafsson I, Palsdottir A . Structure and expression of the human cystatin C gene . Biochem. J. . 268 . 2 . 287–94 . 1990 . 2363674 . 10.1042/bj2680287. 1131430 . etal.
• Levy E, Lopez-Otin C, Ghiso J . Stroke in Icelandic patients with hereditary amyloid angiopathy is related to a mutation in the cystatin C gene, an inhibitor of cysteine proteases . J. Exp. Med. . 169 . 5 . 1771–8 . 1989 . 2541223 . 10.1084/jem.169.5.1771 . 2189307 . etal.
• Saitoh E, Sabatini LM, Eddy RL . The human cystatin C gene (CST3) is a member of the cystatin gene family which is localized on chromosome 20 . Biochem. Biophys. Res. Commun. . 162 . 3 . 1324–31 . 1989 . 2764935 . 10.1016/0006-291X(89)90818-8 . etal.
• Saitoh E, Isemura S, Sanada K . Cystatin superfamily. Evidence that family II cystatin genes are evolutionarily related to family III cystatin genes . Biol. Chem. Hoppe-Seyler . 369 Suppl . 191–7 . 1989 . 3202964 . etal.
• Isemura S, Saitoh E, Sanada K . Characterization and amino acid sequence of a new acidic cysteine proteinase inhibitor (cystatin SA) structurally closely related to cystatin S, from human whole saliva . J. Biochem. . 102 . 4 . 693–704 . 1988 . 3436950 . 10.1093/oxfordjournals.jbchem.a122107.
• Saitoh E, Kim HS, Smithies O, Maeda N . Human cysteine-proteinase inhibitors: nucleotide sequence analysis of three members of the cystatin gene family . Gene . 61 . 3 . 329–38 . 1988 . 3446578 . 10.1016/0378-1119(87)90196-X .
• Abrahamson M, Grubb A, Olafsson I, Lundwall A . Molecular cloning and sequence analysis of cDNA coding for the precursor of the human cysteine proteinase inhibitor cystatin C . FEBS Lett. . 216 . 2 . 229–33 . 1987 . 3495457 . 10.1016/0014-5793(87)80695-6 . 27976400 . free .
• Grubb A, Löfberg H . Human gamma-trace, a basic microprotein: amino acid sequence and presence in the adenohypophysis . Proc. Natl. Acad. Sci. U.S.A. . 79 . 9 . 3024–7 . 1982 . 6283552 . 10.1073/pnas.79.9.3024 . 346341 . 1982PNAS...79.3024G . free .
• Brzin J, Popovic T, Turk V . Human cystatin, a new protein inhibitor of cysteine proteinases . Biochem. Biophys. Res. Commun. . 118 . 1 . 103–9 . 1984 . 6365094 . 10.1016/0006-291X(84)91073-8 . etal.
• Turk V, Brzin J, Longer M . Protein inhibitors of cysteine proteinases. III. Amino-acid sequence of cystatin from chicken egg white . Hoppe-Seyler's Z. Physiol. Chem. . 364 . 11 . 1487–96 . 1984 . 6662498 . 10.1515/bchm2.1983.364.2.1487. etal.
• Dickinson DP, Thiesse M, Dempsey LD, Millar SJ . Genomic cloning, physical mapping, and expression of human type 2 cystatin genes . Crit. Rev. Oral Biol. Med. . 4 . 3–4 . 573–80 . 1993 . 7690606 . 10.1177/10454411930040034401.
• Dickinson DP, Zhao Y, Thiesse M, Siciliano MJ . Direct mapping of seven genes encoding human type 2 cystatins to a single site located at 20p11.2 . Genomics . 24 . 1 . 172–5 . 1995 . 7896273 . 10.1006/geno.1994.1595 .
• Thiesse M, Millar SJ, Dickinson DP . 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 . 1994 . 8179826 . 10.1089/dna.1994.13.97 .
• Janowski R, Kozak M, Jankowska E . Human cystatin C, an amyloidogenic protein, dimerizes through three-dimensional domain swapping . Nat. Struct. Biol. . 8 . 4 . 316–20 . 2001 . 11276250 . 10.1038/86188 . 28916747 . etal.

Notes and References

1. Web site: Entrez Gene: CST2 cystatin SA.