KAT4 Recombinant Protein

Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coordinates these activities is the basal transcription factor TFIID, which binds to the core promoter to position the polymerase properly, serves as the scaffold for assembly of the remainder of the transcription complex, and acts as a channel for regulatory signals. TFIID is composed of the TATA-binding protein (TBP) and a group of evolutionarily conserved proteins known as TBP-associated factors or TAFs. TAFs may participate in basal transcription, serve as coactivators, function in promoter recognition or modify general transcription factors (GTFs) to facilitate complex assembly and transcription initiation. This gene encodes the largest subunit of TFIID. This subunit binds to core promoter sequences encompassing the transcription start site. It also binds to activators and other transcriptional regulators, and these interactions affect the rate of transcription initiation. This subunit contains two independent protein kinase domains at the N and C-terminals, but also possesses acetyltransferase activity and can act as a ubiquitin-activating/conjugating enzyme. This gene is part of a complex transcriptional unit (TAF1/DYT3), wherein some products share exons with TAF1 as well as additional exons downstream.[provided by RefSeq, Aug 2009]

Function: Largest component and core scaffold of the TFIID basal transcription factor complex. Contains novel N- and C-terminal Ser/Thr kinase domains which can autophosphorylate or transphosphorylate other transcription factors. Phosphorylates TP53 on 'Thr-55' which leads to MDM2-mediated degradation of TP53. Phosphorylates GTF2A1 and GTF2F1 on Ser residues. Possesses DNA-binding activity. Essential for progression of the G1 phase of the cell cycle. Ref.1 Ref.8 Ref.9 Ref.11 Ref.12 Ref.14 Ref.17

Catalytic activity: ATP + a protein = ADP + a phosphoprotein.

Cofactor: Magnesium.

Enzyme regulation: Autophosphorylates on Ser residues. Inhibited by retinoblastoma tumor suppressor protein, RB1.

Subunit structure: TAF1 is the largest component of transcription factor TFIID that is composed of TBP and a variety of TBP-associated factors. TAF1, when part of the TFIID complex, interacts with C-terminus of TP53. Component of some MLL1/MLL complex, at least composed of the core components KMT2A/MLL1, ASH2L, HCFC1/HCF1, WDR5 and RBBP5, as well as the facultative components BAP18, CHD8, E2F6, HSP70, INO80C, KANSL1, LAS1L, MAX, MCRS1, MGA, KAT8/MOF, PELP1, PHF20, PRP31, RING2, RUVB1/TIP49A, RUVB2/TIP49B, SENP3, TAF1, TAF4, TAF6, TAF7, TAF9 and TEX10. RB1 interacts with the N-terminal domain of TAF1. Interacts with ASF1A and ASF1B. Interacts with SV40 Large T antigen. Interacts (via bromo domains) with acetylated lysine residues on the N-terminus of histone H1.4, H2A, H2B, H3 and H4 (in vitro). Ref.3 Ref.10 Ref.12 Ref.13 Ref.15 Ref.16 Ref.17 Ref.18 Ref.24

Subcellular location: Nucleus Ref.1.

Post-translational modification: Phosphorylated by casein kinase II in vitro. Ref.9

Involvement in disease: Dystonia 3, torsion, X-linked (DYT3) [MIM:314250]: A X-linked dystonia-parkinsonism disorder. Dystonia is defined by the presence of sustained involuntary muscle contractions, often leading to abnormal postures. DYT3 is characterized by severe progressive torsion dystonia followed by parkinsonism. It has a well-defined pathology of extensive neuronal loss and mosaic gliosis in the striatum (caudate nucleus and putamen) which appears to resemble that in Huntington disease.Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.6 Ref.23

Sequence similarities: Belongs to the TAF1 family.Contains 2 bromo domains.Contains 1 HMG box DNA-binding domain.Contains 2 protein kinase domains.