ATAR, A NOVEL TUMOR-NECROSIS-FACTOR RECEPTOR FAMILY MEMBER, SIGNALS THROUGH TRAF2 AND TRAF5

Members of tumor necrosis factor receptor (TNFR) family signal largely through interactions with death domain proteins and TRAF proteins. He re we report the identification of a novel TNFR family member ATAR. Hu man and mouse ATAR contain 283 and 276 amino acids, respectively, maki ng them the shortest known members of the TNFR superfamily. The recept or is expressed mainly in spleen, thymus, bone marrow, lung, and small intestine, The intracellular domains of human and mouse ATAR share on ly 25% identity, yet both interact with TRAF5 and TRAF2. This TRAF int eraction domain resides at the C-terminal 20 amino acids, Like most ot her TRAF-interacting receptors, overexpression of ATAR activates the t ranscription factor NF-kappa B. Coexpression of ATAR with TRAF5, but n ot TRAF2, results in synergistic activation of NF-kappa B, suggesting potentially different roles for TRAF2 and TRAF5 in post-receptor signa ling.