dFADD, a novel death domain-containing adapter protein for the Drosophila caspase DREDD

Apoptotic cell death occurs through activation of procaspases, the precurso rs of a group of aspartate-specific cysteine proteases known as caspases. P rocaspase activation is mediated by death adapter proteins such as the mamm alian proteins FADD and Apaf-1 and the Caenorhabditis elegans protein CED-4 . These adapters bind to procaspases and facilitate oligomerization and sub sequent auto-proteolytic processing of the zymogens, Here we report cloning and characterization of dFADD, a FADD homologue in Drosophila. dFADD conta ins a death domain that is highly homologous to the FADD death domain, and it also shares a novel domain with;a Drosophila caspase DREDD, which we cal l death-inducing domain, dFADD binds to DREDD through the death-inducing do main and enhances the cell death activity and proteolytic processing of DRE DD. dFADD and DREDD are stabilized by their interaction. The structural and functional similarities between dFADD and FADD suggest the existence of a FADD-like apoptosis pathway in Drosophila.