tokens: In vitro death assays with transient overexpression of deletion constructs of both isoforms using beta - galactosidase as a reporter gene in MCF7 cells suggest the following : 1 ) the nucleotide binding domain may act as a negative regulator of the killing activity of DEFCAP ; 2 ) the LRR / CARD represents a putative constitutively active inducer of apoptosis ; 3 ) the killing activity of LRR / CARD is inhibitable by benzyloxycarbonyl - Val - Ala - Asp ( OMe ) - fluoromethyl ketone and to a lesser extent by Asp - Glu - Val - Asp ( OMe ) - fluoromethyl ketone ; and 4 ) the CARD is critical for killing activity of DEFCAP .