Histone-like TAFs within the PCAF Histone Acetylase Complex

PCAF histone acetylase plays a role in regulation of transcription, cell cycle progression, and differentiation. Here, we show that PCAF is found in a complex consisting of more than 20 distinct polypeptides. Strikingly, some polypeptides are identical to TBP-associated factors (TAFs), which are subunits of TFIID. Like TFIID, histone fold–containing factors are present within the PCAF complex. The histone H3– and H2B–like subunits within the PCAF complex are identical to those within TFIID, namely, hTAF II31 and hTAF II20/15, respectively. The PCAF complex has a novel histone H4–like subunit with similarity to hTAF II80 that interacts with the histone H3–like domain of hTAF II31. Moreover, the PCAF complex has a novel subunit with WD40 repeats having a similarity to hTAF II100.