Induces activation of MAPK14/p38 cascade, when overexpressed (PubMed:28688764). Induces apoptosis, when overexpressed (PubMed:19969290). Interacts with RELT, RELL1 and OXSR1 (PubMed:16389068). Interacts with PLSCR1 (PubMed:22052202). Interacts with TRAF2 (PubMed:19969290). Primarily expressed in spleen, thymus, testis, peripheral blood leukocytes, brain and placenta. Not detected in prostate, ovary, small intestine, colon, heart, lung, liver, skeletal muscle, kidney and pancreas. Phosphorylated in vitro by OXSR1. Belongs to the RELT family.