ARC Antibody #94147

Apoptosis repressor with caspase recruitment domain (ARC), also independently identified as muscle-enriched cytoplasmic protein (MYP), is a CARD domain protein that regulates apoptosis (1). The ARC protein CARD domain is highly homologous to those in other cell death regulators, including caspase-2, caspase-9, RAIDD, and Apaf-1 (2). The NOL3 gene encodes both the cytoplasmic ARC protein and a 30 kDa nucleolar protein (Nop30) that is involved in RNA splicing. ARC is encoded from isoform 2 of NOL3, while isoform 1 produced by alternative splicing encodes Nop30. Both ARC and Nop30 proteins share common amino-terminal sequences (3). Research studies show that ARC can bind to caspase-8 and caspase-2 and inhibit apoptosis through extrinsic pathways that involve the receptor proteins Fas, TNFR1, and DR3 (1). Additional research indicates that the ARC anti-apoptotic mechanism may include both intrinsic (mitochondrial) and extrinsic (death receptor) pathways (4). In addition to binding caspases, ARC can disrupt the interaction with the death domains of Fas and FADD, which inhibits death-inducing signaling complex (DISC) assembly. The CARD domain of ARC can inhibit intrinsic apoptosis through binding to the pro-apoptotic Bax protein (5). Phosphorylation of ARC at Thr149 by CK2 is required for targeting of ARC to the mitochondria (6). ARC is able to suppress necroptosis, a programmed pathway of necrosis triggered by blocking the recruitment of RIP1 to TNFR1 (7). Expression of ARC protein is predominantly seen in terminally differentiated cells under normal conditions and is markedly induced in a variety of cancers including pancreatic, colorectal, breast, lung, glioblastoma, liver, kidney, melanoma, and acute myeloid leukemia (1, 8-12).