Isolation and partial characterization of a protease involved in Fas-induced apoptosis.

Protease involvement has been implicated in the signalling process of activation-induced apoptosis. Here we report the isolation of a protease from Jurkat T cells undergoing Fas-induced apoptosis. Although the protease probably is a serine protease, it seems to be distantly related to members of the ICE/ced-3/Ich-1(nedd-2) family. In a cell-free system using isolated thymocyte nuclei, the protease rapidly induces DNA fragmentation and morphological changes typically seen in apoptosis. Our results clearly show protease activation downstream to Fas-ligation and implicate an important role for the isolated protease in signalling of Fas-induced apoptosis.