Fig. 1

Fas/APO-1-interacting proteins

(A) Models of membrane proximal events in Fas/APO-1 signaling. On the left, Fas ligand binding has caused the aggregation of Fas/APO-1 cytoplasmic domains and/or the heterotypic association of other death domain-containing proteins (e.g., RIP, MORT1/FADD). Other Fas-associated proteins or modifiers of the Fas/APO-1 signal (e.g., FAP-1, HCP) may also be components of the complex, and may serve in trans to activate the signaling cascade. On the right, this complex had existed preformed and upon ligand binding was displaced from the membrane by the homotypic association of Fas/APO-1 death domains. The complex can now freely act in the cytoplasm. (B) Interactions between Fas- and TNF-R1-associated proteins. Known interactions are shown with solid lines, while interactions for which there is some evidence are shown with dotted lines. Proteins for which self-association has been demonstrated are indicated as trimers. Degree of shading represents the extent of amino acid identity with the Fas/APO-1 death domain (the order is: RIP > TNF-R1 = MORT1/FADD > TRADD).