InterPro domain: IPR037264

The TATA Binding Protein (TBP) Associated Factor 5 (TAF5) is one of several TAFs that bind TBP and are involved in forming Transcription Factor IID (TFIID) complex. TFIID plays an important role in the recognition of promoter DNA and assembly of the preinitiation complex. TFIID complex is composed of the TBP and at least 13 TAFs. In yeast and human cells, TAFs have been found as components of other complexes besides TFIID [ 1 ].

This region is an all-alpha domain associated with the WD40 helical bundle of the TAF5 subunit of transcription factor TFIID. The domain has distant structural similarity to RNA polymerase II CTD interacting factors. It contains several conserved clefts that are likely to be critical for TFIID complex assembly [ 2 ]. The TAF5 subunit is present twice in the TFIID complex and is critical for the function and assembly of the complex, and the NTD2 (second N-terminal domain) and N-terminal domain are crucial for homodimerisation [ 3 ]. TAF5 has a paralogue gene (TAF5L) which has a redundant function [ 4 ].

The N-terminal domain of TAF5 has a multihelical structure with a C-terminal beta-alpha(2)-beta motif, one central buried helix and parallel beta-ribbon.

1. TBP-associated factors (TAFIIs): multiple, selective transcriptional mediators in common complexes. Trends Biochem. Sci. 25, 59-63
2. Structural analysis and dimerization potential of the human TAF5 subunit of TFIID. Proc. Natl. Acad. Sci. U.S.A. 104, 1189-94
3. Crystal structure, biochemical and genetic characterization of yeast and E. cuniculi TAF(II)5 N-terminal domain: implications for TFIID assembly. J. Mol. Biol. 368, 1292-306
4. The TAF5L gene on chromosome 1q42 is associated with type 1 diabetes in Russian affected patients. Autoimmunity 38, 283-93