DED Domain

No Image The DED structure consists of six antiparallel alpha-helices. The structure is similar to the death domain and caspase recruitment domain (CARD) however these domains are functionally distinct. For example, the procaspase-8 DED does not interact with the Apaf-1 CARD. Based on studies of the Apaf-1 CARD and studies of FADD DED, the homotypic interaction domain of DED may centre around the second and third alpha-helices. The figure shows the death effector domain of a mutant FADD protein.

Structure Reference:
Eberstadt, M. et al. (1998) Nature. 392 (6679): 941-5. PDB: 1A1W.

Domain binding and function:
The death-effector domain (DED) is a protein interaction domain found in inactive procaspases (cysteine proteases) and proteins that regulate caspase activation in the apoptosis cascade. Similar to the CARDs, the DED recruits procaspases into complexes with members of the TNF-receptor superfamily. This recruitment is mediated by a homotypic interaction between the procaspase DED and a second DED in an adaptor molecule that is directly associated with activated TNF receptors. Complex formation allows transprocessing of procaspase to the active form. This, in turn, activates downstream caspases and initiates apoptosis.
Examples of Proteins: 
Homotypic Binding partner Function
Pro-caspase-8 FADD adaptor protein Activation of apoptosis by the Fas receptor
Flame-1 (aka FLIP, I-FLICE, Usurpin etc.) caspase activation inhibitor FADD adaptor protein Pro-caspase8

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