A modulator of regulatory cellular events occurring intracellularly which are mediated by regulatory proteins containing a `death domain` motif is provided. The `death domain` is a regulatory portion of the regulatory proteins, and the modulator is capable of interacting with one or more `death domain` motifs contained in the regulatory proteins and affecting the regulatory action of one or more of the regulatory proteins. The modulator preferably is capable of interacting with `death domain` motifs within p55-TNF-R, FAS/APO1-R, NGF-R, MORT-1, RIP, TRADD, or ankyrin. A method for producing the modulators is also provided. The modulators are useful for modulating functions mediated in cells by proteins containing the `death domain`.