Apoptosis, also known as programmed cell death, plays major roles in development and normal tissue turnover in addition to tumor formation. Apoptosis is regulated by death domain (DD) and/or caspase recruitment domain (CARD) containing molecules and the caspase family of proteases. CARD domain containing cell death regulators include RAIDD, Apaf-1, caspase-9, and caspase-2. A novel CARD domain containing protein was recently identified and designated ARC for apoptosis repressor with CARD. An alternate splicing isoform of ARC was identified as Nop30. While ARC interacts with caspase-2 and -8 and suppresses apoptosis induced by cell death adapters FADD and TRADD and by cell death receptors Fas, TNFR-1 and DR3, Nop30 multimerizes and binds to the splicing factor SRp30c and may act to influence alternative splice site selection in vivo. The Nop30 antibody will not detect ARC protein.
