PCAF-associated factor PAF400 is almost identical to TRRAP-PAF is not a protein kinase. TRRAP and GCN5 co-expression stimulated E2F-mediated transactivation. TRRAP is an essential cofactor for both the c-MYC and E1A/E2F oncogenic transcription factor, TIP49 (RuvB-like 1 (E. coli)) to also binds to the E2F1 transactivation domain. The (HAT) complex is responsible for acetylation of the N-terminal tails of histone H3-H4 and H2A homologous (H3K4 trimethylation in vivo requires prior ubiquitination of H2B and the nutrient sensing complex Uri/Prefoldin with TIP49, as a separate biochemically distinct complex ATPase as a cofactor) to human TIP60 (HTATIP) part of a multisubunit NuA4 complex with HAT activity including TRRAP assigned to 7q21.3-q22.1: [§§]. Trrap is, essential for early development and required for maintain mitotic chromatin assembly.