A superfamilia da cistatina comprende proteínas que conteñen múltiples secuencias de tipo cistatina. Algúns dos membros son activos inhibidores de cisteína proteases, mentres que outros perderon ou talvez nunca adquiriron esta actividade inhibitoria. Hai tres familias inhibidoras nesta superfamilia, incluíndo as cistatinas de tipo 1 (stefinas[3]), as cistatinas de tipo 2 e os cininóxenos. Este xene codifica unha stefina que funciona como un inhibidor de cisteína protease intracelular. A proteína pode formar un dímero estabilizado por forzas non covalentes, inhibindo a papaína e as catepsinas L, H e B. Pénsase que esta proteína ten unha función na protección contra proteases que saen dos lisosomas. As evidencias indican que as mutacións neste xene son responsables dos defectos primarios en pacientes con epilepsia mioclónica progresiva (EPM1).[2]
↑Pennacchio LA, Lehesjoki AE, Stone NE, Willour VL, Virtaneva K, Miao J, D'Amato E, Ramirez L, Faham M, Koskiniemi M, Warrington JA, Norio R, de la Chapelle A, Cox DR, Myers RM (abril de 1996). "Mutations in the gene encoding cystatin B in progressive myoclonus epilepsy (EPM1)". Science271 (5256): 1731–4. Bibcode:1996Sci...271.1731P. PMID8596935. doi:10.1126/science.271.5256.1731.
↑O nome procede do Instituto Stefan, onde foron descubertas. (Machleidt W, Borchart U, Fritz H, Brzin J, Ritonja A, Turk V (novembro de 1983). "Protein inhibitors of cysteine proteinases. II. Primary structure of stefin, a cytosolic protein inhibitor of cysteine proteinases from human polymorphonuclear granulocytes". Hoppe-Seyler's Zeitschrift für Physiologische Chemie364 (11): 1481–6. PMID6689312. doi:10.1515/bchm2.1983.364.2.1481.)
↑Pavlova, Alona; Björk Ingemar (setembro de 2003). "Grafting of features of cystatins C or B into the N-terminal region or second binding loop of cystatin A (stefin A) substantially enhances inhibition of cysteine proteinases". Biochemistry (United States) 42 (38): 11326–33. ISSN0006-2960. PMID14503883. doi:10.1021/bi030119v.
Järvinen M, Rinne A, Hopsu-Havu VK (1988). "Human cystatins in normal and diseased tissues--a review.". Acta Histochem.82 (1): 5–18. PMID3122506. doi:10.1016/s0065-1281(87)80043-0.
Kos J, Lah TT (1998). "Cysteine proteinases and their endogenous inhibitors: target proteins for prognosis, diagnosis and therapy in cancer (review).". Oncol. Rep.5 (6): 1349–61. PMID9769367. doi:10.3892/or.5.6.1349.
Jerala R, Trstenjak M, Lenarcic B, Turk V (1988). "Cloning a synthetic gene for human stefin B and its expression in E. coli.". FEBS Lett.239 (1): 41–4. PMID3053245. doi:10.1016/0014-5793(88)80541-6.
Lenarcic B, Kos J, Dolenc I, et al. (1988). "Cathepsin D inactivates cysteine proteinase inhibitors, cystatins.". Biochem. Biophys. Res. Commun.154 (2): 765–72. PMID3261170. doi:10.1016/0006-291X(88)90206-9.
Ritonja A, Machleidt W, Barrett AJ (1985). "Amino acid sequence of the intracellular cysteine proteinase inhibitor cystatin B from human liver.". Biochem. Biophys. Res. Commun.131 (3): 1187–92. PMID3902020. doi:10.1016/0006-291X(85)90216-5.
Spiess E, Brüning A, Gack S, et al. (1994). "Cathepsin B activity in human lung tumor cell lines: ultrastructural localization, pH sensitivity, and inhibitor status at the cellular level.". J. Histochem. Cytochem.42 (7): 917–29. PMID8014475. doi:10.1177/42.7.8014475.
Lehesjoki AE, Koskiniemi M, Norio R, et al. (1993). "Localization of the EPM1 gene for progressive myoclonus epilepsy on chromosome 21: linkage disequilibrium allows high resolution mapping.". Hum. Mol. Genet.2 (8): 1229–34. PMID8104628. doi:10.1093/hmg/2.8.1229.
Lafrenière RG, Rochefort DL, Chrétien N, et al. (1997). "Unstable insertion in the 5' flanking region of the cystatin B gene is the most common mutation in progressive myoclonus epilepsy type 1, EPM1.". Nat. Genet.15 (3): 298–302. PMID9054946. doi:10.1038/ng0397-298.
