Participates in TNF-alpha-induced blockade of glucocorticoid receptor (GR) transactivation at the nuclear receptor coactivator level, upstream and independently of NF-kappa-B. Suppresses both NCOA2- and NCOA3-induced enhancement of GR transactivation. Involved in TNF-alpha-induced activation of NF-kappa-B via a TRAF2-dependent pathway. Acts as a downstream mediator for CASP8-induced activation of NF-kappa-B. Required for the activation of CASP8 in FAS-mediated apoptosis. Required for histone gene transcription and progression through S phase. Self-associates. Component of the death-inducing signaling complex (DISC) with CASP8, FADD and FAS. Interacts with NCOA2 and NCOA3. Interacts with SRRT. Interacts with TRAF2. Interacts with NPAT. Interacts (via SIM domains) with SUMO1 and SUMO2. Interacts with SP100; may negatively regulate CASP8AP2 export from the nucleus to the cytoplasm. Exported from the nucleus to the mitochondria upon FAS activation. By TNF which induces strong nuclear localization. Contaminating sequence. Potential poly-A sequence starting in position 364. Truncated N-terminus.