Caspase-9 and Apaf-1 bind to each other, which leads to caspase activation. Activated caspase-9 cleaves and activates caspase-3, one of the key proteases responsible for the proteolytic cleavage of many proteins in apoptosis. Caspase-9 plays a central role in cell death induced by a wide variety of apoptosis inducers including TNFa, TRAIL, anti-CD95, FADD, and TRADD. Caspase-9 is expressed in a variety of human tissues. Recently, a novel isoform of rat caspase-9 has been identified in which the C-terminus of full-length caspase-9 is replaced with an alternative peptide sequence. This protein, called Caspase-9 (CTD) (where CTD is carboxyl-terminal divergent) is expressed in multiple tissues, with the relative highest levels observed in ovary and heart. The variant C-terminus of CTD in rat is derived from an alternative exon of the rat caspase-9 gene. CTD was found primarily in the cytoplasm and was not detected in the nucleus. CTD proenzyme is not processed in the cells and lacks apoptotic activity. The CTD-transfected cells are resistant to caspase induction by cytochrome c, suggesting the CTD acts as a dominant-negative variant.WARNING This product is not for human or veterinary use.
