TAF1 is the largest component and core scaffold of the TFIID basal transcription factor complex which also includes TBP. The protein is able to auto phosphorylate or trans phosphorylate other transcription factors such as TP53 on ‘Thr-55’, leading to MDM2-mediated degradation of TP53, and GTF2A1 and GTF2F1 on Ser residues. TAF1 possesses DNA-binding activity and is essential for progression of the G1 phase of the cell cycle.