RIPS is a novel gene product containing a N-terminal kinase domain that sha
res extensive homology with the corresponding domain in RIP (receptor-inter
acting protein) and RIPE. Unlike RIP, which has a C-terminal death domain,
and RIPE, which has a C-terminal caspase activation and recruitment domain,
RIPS has a unique C terminus. RIPS binds RIP through its unique C-terminal
segment and by virtue of this interaction is recruited to the tumor necros
is factor (TNF) receptor-1 signaling complex. Previous studies have shown t
hat RIP mediates TNF-induced activation of the anti-apoptotic NF-KB pathway
. RIPS, however, attenuates both RIP and TNF receptor-1-induced NF-KB activ
ation. Overexpression studies revealed RIPS to be a potent inducer of apopt
osis, capable of selectively binding to large prodomain initiator caspases.