TAF4
Description
The TAF4 (TATA-box binding protein associated factor 4) is a protein-coding gene located on chromosome 20.
Transcription initiation factor TFIID subunit 4 is a protein that in humans is encoded by the TAF4 gene. Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coordinates these activities is transcription factor IID (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 one of the larger subunits of TFIID that has been shown to potentiate transcriptional activation by retinoic acid, thyroid hormone and vitamin D3 receptors. In addition, this subunit interacts with the transcription factor CREB, which has a glutamine-rich activation domain, and binds to other proteins containing glutamine-rich regions. Aberrant binding to this subunit by proteins with expanded polyglutamine regions has been suggested as one of the pathogenetic mechanisms underlying a group of neurodegenerative disorders referred to as polyglutamine diseases. TAF4 has been shown to interact with: CBX5m, TATA binding protein, and Transcription initiation protein SPT3 homolog. Yeast TFIID comprises the TATA binding protein and 14 TBP-associated factors (TAFIIs), nine of which contain histone-fold domains (INTERPRO).
The TFIID complex is a key player in initiating RNA polymerase II (Pol II)-dependent transcription. TFIID recognizes and binds to promoters, whether they contain a TATA box or not, through its TBP (TATA-box-binding protein) subunit. This binding then triggers the assembly of the pre-initiation complex (PIC). TFIID comprises TBP and TBP-associated factors (TAFs), including TAF1, TAF2, TAF3, TAF4, TAF5, TAF6, TAF7, TAF8, TAF9, TAF10, TAF11, TAF12, and TAF13. TAF4 contributes to maintaining a connection between the TFIID and TFIIA complexes while they are bound to the promoter, together with TBP, during PIC assembly. It also enhances transcriptional activation by the AF-2S domain of retinoic acid, vitamin D3, and thyroid hormone.
TAF4 is also known as MRD73, TAF(II)130, TAF(II)135, TAF2C, TAF2C1, TAF4A, TAFII-130, TAFII-135, TAFII130, TAFII135.
