Participates in TNF-induced blockade of glucocorticoid receptor (GR) transactivation at the nuclear receptor coactivator level, upstream and independently of NF-kappa-B (PubMed:12477726, PubMed:15698540). Suppresses both NCOA2- and NCOA3-induced enhancement of GR transactivation (PubMed:12477726, PubMed:15698540). Involved in TNF-induced activation of NF-kappa-B via a TRAF2-dependent pathway (By similarity). Acts as a downstream mediator for CASP8-induced activation of NF-kappa-B (PubMed:17245429). Required for the activation of CASP8 in FAS-mediated apoptosis (PubMed:17245429). Involved for histone gene transcription and progression through S phase: required for the generation of mature histone mRNAs following the 3' end cleavage of histone pre-mRNAs (PubMed:17003125, PubMed:19854135, PubMed:32367068). {ECO:0000250|UniProtKB:Q9WUF3, ECO:0000269|PubMed:12477726, ECO:0000269|PubMed:15698540, ECO:0000269|PubMed:17003125, ECO:0000269|PubMed:17245429, ECO:0000269|PubMed:19854135, ECO:0000269|PubMed:32367068}. This is the function of CASP8AP2 (caspase 8 associated protein 2, Ensembl gene identifier ENSG00000118412).