Induces activation of MAPK14/p38 cascade, when overexpressed (PubMed:28688764). Induces apoptosis, when overexpressed (PubMed:19969290). Interacts with RELT, RELL2 and OXSR1 (PubMed:16389068). Interacts with PLSCR1 (PubMed:22052202). Widely expressed. Expressed at highest levels in the placenta, skeletal muscle, spleen and testis. Phosphorylated in vitro by OXSR1. Belongs to the RELT family.