Structures, Domains and Functions in Cell Death (DD, DED, CARD, PYD)

Abstract

The death domain (DD), death effector domain (DED), caspase-recruitment domain (CARD) and pyrin domain (PYD) are subfamilies of the DD superfamily. By mediating homotypic interactions, these proteins play important roles in the assembly and activation of apoptotic signalling complexes. They are responsible for caspase recruitment and for formation of oligomeric platforms for signalling. DD superfamily proteins have a common six-helical bundle fold and show different surface features for each of the subfamilies. Most interestingly, the homotypic interactions within each subfamily are mostly mediated by asymmetric contacts, in which different surfaces of the interaction partners are adjacent to each other. The DD superfamily proteins appear to use three common types of asymmetric interactions to assemble into large oligomeric complexes.

Key concepts

• Death domains (DDs), death effector domains (DEDs), caspase-recruitment domains (CARDs) and pyrin domains (PYDs) are protein:protein interaction modules for formation of caspase-activating complexes.

• DDs, DEDs, CARDs and PYDs share a common six-helical bundle fold.

• Interactions within these domains are mostly asymmetric and conserved.