Plays a role as a mediator of E2F1-induced apoptosis in the absence of p53/TP53 (PubMed:15565177). Plays a role as a mediator of E2F1-induced apoptosis in the absence of p53/TP53. Inhibits TLR9 response to nucelic acids and regulates TLR9-mediated innate immune response (By similarity). Interacts with RTN4 (isoform B). Colocalizes with COX4I1. Expressed in lung and in primary lung squamous cell carcinoma (LSCC). Up-regulated in the mitochondria by E2F1 after addition of 4-hydroxytamoxifen (at protein level). Extended N-terminus.