TAFs are components of the transcription factor IID (TFIID) complex, PCAF histone acetylase complex and TBP-free TAFII complex (TFTC). TIIFD is a multimeric protein complex that plays a central role in mediating promoter responses to various activators and repressors.
The general transcription factor IID (TFIID) plays a central role in the initiation of RNA polymerase II (Pol II)-dependent transcription by nucleating pre-initiation complex (PIC) assembly at the core promoter. TFIID comprises the TATA-binding protein (TBP) and 13 TBP-associated factors (TAF1-13), which specifically interact with a variety of core promoter DNA sequences.
Here we present the cryogenic-electron microscopy (cryo-EM) structure of human SAGA (hSAGA)|Human SAGA is a 20-subunit, 1.4-MDa complex with five functional modules (Fig. (Fig.1a):1a): a scaffolding core that includes TBP-associated factors (TAFs); a TRRAP (Transformation/Transcription domain Associated Protein) containing a phosphoinositide-3-kinase (PI3K)-related pseudoprotein kinase (ΨPIKK); a histone acetyltransferase (HAT); a deubiquitinase (DUB) and a metazoan-specific splicing (SPL) module