Plays a role as a mediator of E2F1-induced apoptosis in the absence of p53/TP53 (By similarity). Inhibits TLR9 response to nucelic acids and regulates TLR9-mediated innate immune response (PubMed:25917084). Interacts with RTN4 (isoform B). Colocalizes with COX4I1. It is uncertain whether Met-1 or Met-52 is the initiator. Extended N-terminus. The sequence differs from that shown because it seems to be derived from a pre-mRNA.