MA3-945 detects calpastatin from bovine, human, canine, pig, rabbit, and rat tissues and cells. This antibody does not cross-react with calpains or calmodulin.
MA3-945 has been successfully used in Western blot, immunohistochemistry, and immunocytochemical procedures. By Western blot, this antibody detects 150, 125, 90 and 70 kDa proteins which have been suggested to be proteins translated from different start sites of the calpastatin gene. Immunofluorescence staining of calpastatin in porcine LLC-PK1 cells with MA3-945 results in diffuse cytoplasmic staining and weak nuclear staining.
The MA3-945 antigen is bovine skeletal muscle calpastatin. This antibody recognizes an epitope found between amino acid residues 295-501 (domain II) of human calpastatin.
The calpain system has been detected in every vertebrate tissue examined, and has been suggested to play a regulatory role in cellular protein metabolism. This regulatory role may have important implications in platelet aggregation and pathologies associated with altered calcium homeostasis and protein metabolism such as ischemic cell injury and degenerative diseases. Inhibitors of calpain have been shown to block dexamethasone and low-level irradiation induced apoptosis in thymocytes suggesting that calpain has a regulatory or mechanistic role in apoptotic cell death.
Calpastatin, a specific endogenous inhibitor of calpain, has a predicted molecular weight of ~77 kDa and an internal repeat of four homologous domains which allow it to inhibit multiple calpain molecules simultaneously. It functions by binding to calpain when calpain binds calcium. When calpastatin is subjected to proteolytic digestion, fragments of calpastatin as small as 15 kDa still retain inhibitory activity.
For Research Use Only. Not for use in diagnostic procedures. Not for resale without express authorization.
Protein Aliases: Calpain inhibitor; Calpastatin; calpastatin isoform III; calpastatin type I; calpastatin type II; calpastatin type III; Erythrocyte calpastatin; Sperm BS-17 component
Gene Aliases: BOS_8501; BS-17; CAST; PLACK