High impact information on Taf4

• Moreover, purified Sp1 selectively binds recombinant TAF110 in vitro [1].
• This triple complex supports Sp1 activation and reveals specific interactions between TAFII250, TBP and TAFII110 [2].
• Within the basal transcription factor complex TFIID, two specific targets, TAFII110 and TAFII60, served as coactivators to mediate transcriptional activation by these two enhancer binding proteins [3].
• Mutagenesis studies in combination with protein binding experiments and reconstituted transcription reactions identified two independent activation domains of BCD that target different coactivator subunits (TAFII110 and TAFII60) of the basal transcription factor IID (TFIID) [4].
• Consistent with this, interaction between RBP and TFIIA precludes interaction with dTAFII110 [5].

Biological context of Taf4

• The deduced amino acid sequence of TAF110 revealed the presence of several glutamine- and serine/threonine-rich regions reminiscent of the protein-protein interaction domains of the regulatory transcription factor Sp1 that are involved in transcription activation and multimerization [1].
• In vitro transcription reactions and protein binding assays implicate the TAFII110 and TAFII60 subunits of the TFIID complex in contributing to Dorsal-mediated activation [6].
• Biochemical analyses demonstrate that PI3K_68D has a novel substrate specificity in vitro, restricted to phosphatidylinositol and phosphatidylinositol 4-phosphate, and is unable to phosphorylate phosphatidylinositol (4,5)-bisphosphate, the implied in vivo substrate for p110 [7].

Associations of Taf4 with chemical compounds

• In both Drosophila cells and yeast, TAF110 specifically interacts with the glutamine-rich activation domains of Sp1 [1].
• The PI3K_68D cDNA encodes a protein of 210 kDa, which lacks sequences implicated in linking p110 PI 3-kinases to p85 adaptor proteins, but contains an amino-terminal proline-rich sequence, which could bind to SH3 domains, and a carboxy-terminal C2 domain [7].

Other interactions of Taf4

• Coimmunoprecipitation studies with anti-dTBP, anti-dTFIIA-L, and anti-TAF antibodies indicated a tight association of the endogenous dTFIIA and dTFIID [8].
• Strikingly, the structural interaction is tissue specific: nht did not interact with dTAF12 and dTAF4 did not interact with rye in a bacterial co-expression assay [9].
• This means that the interactions observed in vitro between Bcd and TAFII60 or TAFII110 aid transcriptional activation but are dispensable for normal development [10].

Analytical, diagnostic and therapeutic context of Taf4

• Molecular cloning and functional analysis of Drosophila TAF110 reveal properties expected of coactivators [1].

References