Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P20226 (TATA-binding protein)
 1,297 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have identified novel interactions between the human (h)TATA-binding protein-associated factor TAF(II)55 and the ligand-binding domains (LBDs) of the nuclear receptors for vitamin D(3) (VDR) and thyroid hormone (TRalpha). Following expression in Cos cells, hTAF(II)55 interacts with the VDR and TRalpha LBDs in a ligand-independent manner whereas no interactions with the retinoid X receptors (RXRs) or with other receptors were observed. Deletion mapping indicates that hTAF(II)55 interacts with a 40-amino-acid region spanning alpha-helices H3 to H5 of the VDR and TRalpha LBDs but not with the equivalent highly related region of RXRgamma. TAF(II)55 also interacts with chimeric receptors in which the H3-to-H5 region of RXRgamma has been replaced with that of the VDR or TRalpha. Furthermore, replacement of two single amino acids of the RXRgamma LBD with their VDR counterparts allows the RXRgamma LBD to interact with hTAF(II)55 while the corresponding double substitution allows a much stronger interaction. In transfection experiments, the single mutated RXRgamma LBDs activate transcription to fivefold higher levels than wild-type RXRgamma while the double mutation activates transcription to a level comparable to that observed with the VDR. There is therefore a correlation between the ability of the modified RXRs to interact with hTAF(II)55 and transactivation. These results strongly suggest that the TAF(II)55 interactions with the modified RXR LBDs modulate transcriptional activation.
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PMID:Human TAF(II)55 interacts with the vitamin D(3) and thyroid hormone receptors and with derivatives of the retinoid X receptor that have altered transactivation properties. 1040 38

Using coexpression in COS cells, we have identified novel interactions between the human TATA-binding protein-associated factor 28 (hTAF(II)28) component of transcription factor IID and the ligand binding domains (LBDs) of the nuclear receptors for vitamin D3 (VDR) and thyroid hormone (TRalpha). Interaction between hTAF(II)28 and the VDR and TR LBDs was ligand-reversible, whereas no interactions between hTAF(II)28 and the retinoid X receptors (RXRs) or other receptors were observed. TAF(II)28 interacted with two regions of the VDR, a 40-amino acid region spanning alpha-helices H3-H5 and alpha-helix H8. Interactions were also observed with the H3-H5 region of the TRalpha but not with the equivalent highly related region of the RXRgamma. Fine mapping using RXR derivatives in which single amino acids of the RXRgamma LBD have been replaced with their VDR counterparts shows that the determinants for interaction with hTAF(II)28 are located in alpha-helix H3 and are not identical to those previously identified for interactions with hTAF(II)55. We also describe a mutation in the H3-H5 region of the VDR LBD, which abolishes transactivation, and we show that interaction of hTAF(II)28 with this mutant is no longer ligand-reversible.
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PMID:The human transcription factor IID subunit human TATA-binding protein-associated factor 28 interacts in a ligand-reversible manner with the vitamin D(3) and thyroid hormone receptors. 1074 85