Fig. 7. Models for the mechanism by which transgenic Bcl-2 might inhibit nematode PCD. (A) The core nematode PCD pathway is depicted. (B) The previously presumed model for the inhibition of nematode cell death by Bcl-2. Data presented here indicate that Bcl-2 cannot bind CED-4 nor inhibit its activity, arguing against this model. (C) Our results suggest this model, in which Bcl-2 overexpression might provide an alternative `sink' for EGL-1, thereby preventing EGL-1 from accessing CED-9. CED-9 would then be available to inhibit CED-4 and thus suppress PCD.