Figure 2.
The L2′ loop of CED-3 is required for stable association between CED-3 and the CED-4 apoptosome. (A) The L2′ loop is required for CED-3 to associate with the CED-4 apoptosome. Gel filtration analysis reveals that removal of the L2′ loop, but not the L2 loop, in the two-chain CED-3 (residues 198–374, 389–503, and C358A) resulted in loss of binding to the CED-4 apoptosome. (B) Deletion of the L2′ loop in CED-3 results in loss of CED-4-mediated stimulation of CED protease activity. (C) Missense mutations in the L2′ loop of CED-3 leads to abrogation of CED-4-mediated stimulation of CED protease activity. The three missense mutations L391D, F392D, and N393D target three consecutive amino acids in the L2′ loop of CED-3.