The TBP-associated factors (TAF) are proteins that associate with the

TATA-binding protein The TATA-binding protein (TBP) is a general transcription factor that binds specifically to a DNA sequence called the TATA box. This DNA sequence is found about 30 base pairs upstream of the transcription start site in some eukaryotic gene pr ...

in transcription initiation. It is a part of the

transcription Transcription refers to the process of converting sounds (voice, music etc.) into letters or musical notes, or producing a copy of something in another medium, including: Genetics * Transcription (biology), the copying of DNA into RNA, the fir ...

initiation factor Initiation factors are proteins that bind to the small subunit of the ribosome during the initiation of translation, a part of protein biosynthesis. Initiation factors can interact with repressors to slow down or prevent translation. They have the ...

TFIID Transcription factor II D (TFIID) is one of several general transcription factors that make up the RNA polymerase II preinitiation complex. RNA polymerase II holoenzyme is a form of eukaryotic RNA polymerase II that is recruited to the promoters o ...

multimeric

protein complex A protein complex or multiprotein complex is a group of two or more associated polypeptide chains. Protein complexes are distinct from multienzyme complexes, in which multiple catalytic domains are found in a single polypeptide chain. Protein c ...

. It also makes up many other factors, including SL1. They mediate the formation of the

transcription preinitiation complex The preinitiation complex (abbreviated PIC) is a complex of approximately 100 proteins that is necessary for the transcription of protein-coding genes in eukaryotes and archaea. The preinitiation complex positions RNA polymerase II at gene transc ...

, a step preceding transcription of DNA to

RNA Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...

RNA polymerase II RNA polymerase II (RNAP II and Pol II) is a multiprotein complex that transcribes DNA into precursors of messenger RNA (mRNA) and most small nuclear RNA (snRNA) and microRNA. It is one of the three RNAP enzymes found in the nucleus of eukaryoti ...

. TAFs have a signature N-terminal

histone In biology, histones are highly basic proteins abundant in lysine and arginine residues that are found in eukaryotic cell nuclei. They act as spools around which DNA winds to create structural units called nucleosomes. Nucleosomes in turn are wr ...

-like fold domain (HFD). This domain is implicated in the pairwise interaction among specific TAFs.

Function

TFIID

TFIID plays a central role in mediating promoter responses to various activators and

repressors In molecular genetics, a repressor is a DNA-binding protein, DNA- or RNA-binding protein that inhibits the Gene expression, expression of one or more genes by binding to the Operator (biology), operator or associated Silencer (DNA), silencers. ...

. It

bind BIND () is a suite of software for interacting with the Domain Name System (DNS). Its most prominent component, named (pronounced ''name-dee'': , short for ''name daemon''), performs both of the main DNS server roles, acting as an authoritative n ...

s tightly to TAFII-250 and directly

interact Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of children with intersex traits. The organizati ...

s with TAFII-40. TFIID is composed of TATA binding protein (TBP) and a number of TBP-associated factors (TAFS). TAF is part of the TFIID complex, and interacts with the following: * Specific transcriptional activators * Basal transcription factors * Other TAFIIs * Specific DNA sequences, for example the downstream promoter element or gene-specific core promoter sequence Due to such interactions, they contribute transcription activation and to promoter selectivity. Some pairs of TAF interact with each other to form "lobes" in TFIID. Pairs known or suggested to exist in TFIID include TAF6-TAF9, TAF4-TAF12, TAF11-13, TAF8-TAF10 and TAF3-TAF10.

SL1

Selective factor 1 Selective factor 1 (also known as SL1) is a transcription factor that binds to the promoter of genes and recruits a preinitiation complex to which RNA polymerase I will bind to and begin the transcription of ribosomal RNA (rRNA). Discovery SL1 ...

is composed of the

and three TAF (TATA box-binding protein-associated factor) subunits (

TAF1A TATA box-binding protein-associated factor RNA polymerase I subunit A is an enzyme that in humans is encoded by the ''TAF1A'' gene. Function Initiation of transcription by RNA polymerase I requires the formation of a complex composed of the TA ...

TAF1B TATA box-binding protein-associated factor RNA polymerase I subunit B is an enzyme that in humans is encoded by the ''TAF1B'' gene. Function Initiation of transcription by RNA polymerase I requires the formation of a complex composed of the TAT ...

, and

TAF1C TATA box-binding protein-associated factor RNA polymerase I subunit C is an enzyme that in humans is encoded by the ''TAF1C'' gene. Function Initiation of transcription by RNA polymerase I requires the formation of a complex composed of the TA ...

). These TAFs do not have a histone-like fold domain.

Other complexes

TAF is a part of SAGA (SPT-ADA-GCN5 acetylase) and related coactivation complexes. Such complexes acetylate

tails to activate genes. Human has three SAGA-like complexes:

PCAF P300/CBP-associated factor (PCAF), also known as K(lysine) acetyltransferase 2B (KAT2B), is a human gene and transcriptional coactivator associated with p53. Structure Several domains of PCAF can act independently or in unison to enable its funct ...

, TFTC (TBP-free TAF-containing complex), and STAGA ( SPT3-

TAF9 TAF9 RNA polymerase II, TATA box binding protein (TBP)-associated factor, 32kDa, also known as TAF9, is a protein that in humans is encoded by the ''TAF9'' gene. Function Initiation of transcription by RNA polymerase II requires the activities ...

- GCN5L acetylase). PCAF (GCN5) and KAT2A (GCN5L) are two human homologs of the yeast Gcn5. TAF8, TAF10, and SPT7L forms a small TAF complex called SMAT.

Structure

The N-terminal domain of TAF has a histone-like protein fold. It contains two short

alpha helices The alpha helix (α-helix) is a common motif in the secondary structure of proteins and is a right hand-helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O group of the amino acid located four residues ear ...

and a long central alpha helix.

Human genes

TAF1 Transcription initiation factor TFIID subunit 1, also known as transcription initiation factor TFIID 250 kDa subunit (TAFII-250) or TBP-associated factor 250 kDa (p250), is a protein that in humans is encoded by the ''TAF1'' gene. Function Init ...

(TAFII250) *

TAF2 Transcription initiation factor TFIID subunit 2 is a protein that in humans is encoded by the ''TAF2'' gene. Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coordinates these ...

(CIF150) *

TAF3 Transcription initiation factor TFIID subunit 3 is a protein that in humans is encoded by the ''TAF3'' gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." mea ...

(TAFII140) *

TAF4 Transcription initiation factor TFIID subunit 4 is a protein that in humans is encoded by the ''TAF4'' gene. Function Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coordi ...

(TAFII130/135) *

TAF4B Transcription initiation factor TFIID subunit 4B is a protein that in humans is encoded by the ''TAF4B'' gene. Function TATA-binding protein associated factors (TAFs) participate, with TATA binding protein (TBP; MIM 600075), in the formation of ...

(TAFII105) *

TAF5 Transcription initiation factor TFIID subunit 5 is a protein that in humans is encoded by the ''TAF5'' gene. Function Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coord ...

(TAFII100) *

TAF6 Transcription initiation factor TFIID subunit 6 is a protein that in humans is encoded by the ''TAF6'' gene. Function Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coordi ...

(TAFII70/80) **

TAF6L TAF6-like RNA polymerase II p300/CBP-associated factor-associated factor 65 kDa subunit 6L is an enzyme that in humans is encoded by the ''TAF6L'' gene. Function Initiation of transcription by RNA polymerase II requires the activities of more t ...

(PAF65A) *

TAF7 Transcription initiation factor TFIID subunit 7 also known as TAFII55 is a protein that in humans is encoded by the ''TAF7'' gene. Function The intronless gene for this transcription coactivator is located between the protocadherin beta and ga ...

(TAFII55) *

TAF8 Transcription initiation factor TFIID subunit 8 is a protein that in humans is encoded by the ''TAF8'' gene. This gene encodes one of several TATA-binding protein (TBP)-associated factors (TAFs), which are integral subunits of the general transc ...

(TAFII43) *

(TAFII31/32) *

TAF9B Transcription initiation factor TFIID subunit 9B is a protein that in humans is encoded by the ''TAF9B'' gene. Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coordinates the ...

(TAFII31L) *

TAF10 Transcription initiation factor TFIID subunit 10 is a protein that in humans is encoded by the ''TAF10'' gene. Function Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coo ...

(TAFII30) *

TAF11 Transcription initiation factor TFIID subunit 11 also known as TAFII28, is a protein that in humans is encoded by the ''TAF11'' gene. Function Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptid ...

(TAFII28) *

TAF12 Transcription initiation factor TFIID subunit 12 is a protein that in humans is encoded by the ''TAF12'' gene. Function Control of transcription by RNA polymerase II involves the basal transcription machinery, which is a collection of proteins ...

(TAFII20/15) *

TAF13 Transcription initiation factor TFIID subunit 13 is a protein that in humans is encoded by the ''TAF13'' gene. Function Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coo ...

(TAFII18) *

TAF15 TATA-binding protein-associated factor 2N is a protein that in humans is encoded by the ''TAF15'' gene. Function Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coordinates ...

(TAFII68)

Assorted signatures

TAF domains are spread out across many digital signatures:

References

{{InterPro content, IPR004823, IPR003923 Protein domains