S.Y. Toh, X. Wang and P. Li Identification of the nuclear factor HMG2 as an activator for DFF nuclease activity. A poptosis plays a crucial role during development by eliminating excess cells and allowing for tissue remodelling. Apoptosis machinery is composed of a variety of components, which can be classified as activators, effectors and inhibitors. Caspases, a novel family of proteases, are universal effectors for apoptosis. Caspases are synthesized as inactive zymogens and activated by cleavage at aspartic acid residues.
Caspase activation remains the central step in the regulation of apoptosis.
Using biochemical approaches we have identified and characterized caspase-9. DFF is a heterodimeric protein complex consisting of DFF45 and DFF40. Purified DFF40 alone possesses intrinsic nuclease activity, that is inhibited by its association with DFF45. The proteolytic cleavage of DFF45 by caspase-3 frees DFF40 to function as a nuclease. It is the group's goal to elucidate the molecular mechanism underlying the caspase activation and DNA fragmentation.