Cystatin A antibody [WR-23/2/3/3]

Cystatins are endogenous inhibitors of lysosomal proteases that form a superfamily that is classified into three families (families 1,2 and 3) according to the homology of the amino acid sequences. Cystatin A (also termed acid cysteine proteinase inhibitor, ACPI, stefin A, and epidermal SH- proteinase inhibitor) belongs to family 1 of the cystatin superfamily of proteins. These proteins are natural inhibitors of cysteine proteinases like cathepsin B, H, L, and S. Cystatin A, a 98 amino acid protein (11-13 kDa), is detected in normal squamous epithelium, follicular dendritic cells in lymphoid tissues, thymic epithelial cells (in Hassall_x0019_s corpuscles and in medulla), liver cells, granulocytes and basal epithelial cells in the prostate. Cystatin A is thought to be a tumor suppressor, since an inverse correlation seems to exist between the level of cystatin A and tumor progression, in several malignancies. Also, Cystatin A has been implicated in aging of tissues, Alzheimer disease, viral infections and inflammatory processes. Antibodies that react specifically with cystatin A are useful tools for studying structure-function relationships and cellular or subcellular localization of the molecule.