PTMScan^® Cleaved Caspase Substrate Motif [DE(T/S/A)D] Kit #12810

Apoptosis is a physiological process resulting in a highly regulated, programmed form of cell death that is a normal part of growth and development in multicellular organisms. Aspartic acid-directed cysteine proteases, caspases, are central to the apoptotic mechanism (1). An intrinsic pathway initiates the apoptotic cascade from signals originating within the cell, such as DNA damage, and an extrinsic pathway initiates apoptosis in response to extracellular signals, like FasL. In either case, initiator caspases, such as caspase-8 and 9, begin cleaving downstream substrates that include the effector caspases, such as caspase-3, the most prominent executioner caspase (2,3). These effector caspases amplify the apoptotic cascade to target many critical proteins needed for normal cell function. Apart from its role in developmental biology, the regulation of apoptosis has broad implications for the study of cancer, autoimmune, and infectious diseases among others (4). In the human proteome, there are thousands of known or putative caspase cleavage sites and all are cleaved at an aspartic acid residue, or, in rare cases, a glutamic acid residue. The resultant fragments containing a carboxy-terminal aspartate generally have the XEXD motif with some variation (5). The PTMScan^® Cleaved Caspase Substrate Motif [DE(T/S/A)D] Kit provides a unique and sensitive method for quantifying hundreds of cleaved caspase substrates, including caspase-3 and 7, NEDD1, HDAC3, MCM4, Notch1, eIF2B, raptor, Bid, Smad6, NFAT90, and PTEN among others.