TAF II p18 Background Information
TFIID is a general transcription factor that facilitates the preinitiation complex assembly through direct interactions with the TATA promoter element. TFIID is a multisubunit complex consisting of a small TATA-binding polypeptide and other TBP-associated factors (TAFs). The TAF II family members include p18, p28, p32, p100, p130, p170 and p250, which is the largest subunit of TFIID. TAF II p32 is the human homologue of the Drosophila TAFII40 and is upregulated during apoptosis. TAFII p32 interacts with the activation domain of the viral protein 16, TFIIB and the class II transactivator (CIITA) to modulate transcription. The human and murine TAFII p32 proteins are distinct isoforms, designated TAF II p32 a and b, respectively, and are thought to have individual roles in regulation. TAF II p28 and TAF II p18 interact with one another in vitro and intracellularly, and both interact with TBP through distinct domains. TAF II p28 potentiates transactivation of the estrogen and vitamin D3 receptors (ER and VDR), and is the limiting factor in the RXRa activation pathway.
