Transactivator of transcription

Console S, et al. Antennapedia and HIV transactivator of transcription (TAT) protein transduction domains promote endocytosis of high molecular weight cargo upon binding to cell surface glycosaminoglycans. J Biol Chem 2003 278 35109. 

Zhang L, Levi E, Majumder P, Yu Y, Aboukameel A, Du J, Xu H, Mohammad RM, Hatfield JS, Wali A, Adsay V, Majumdar APN, Rishi AK. Transactivator of transcription-tagged Cell Cycle and Apoptosis Regulatory Protein-1 peptides suppress growth of human breast cancer cells in vitro and in vivo. Mol Cancer Ther. 2007 6 1661-1672. 

A range of synthetic peptides has been proposed for the delivery of nanostructures bearing cargo molecules through the plasma membrane barrier. These are derived from sequences expressed on viruses, such as HIV transactivator of transcription (TAT) [32-36], for which internalization via a glycosaminoglycan (GAG)-mediated... 

The viral protein Rev may also play a role in HIV-1 latency. Expression of the viral Rev protein is essential for the nuclear export of genomic RNA as well as unspliced and/or singly spliced transcripts (Cullen 2003), which are ultimately translated into structural, regulatory, and enzymatic viral proteins. Retention of Rev and Tat (viral transactivator proteins) transcripts in the nucleus of resting CD4h- T cells from HAART patients (Lassen et al. 2006) might be involved in the maintenance of post-integration latency in these cells. Importantly, this phenomenon is non-existent in activated T cells. 

Ligand-bound corticosteroid receptors have been shown to interact to form heterodimers with other transcription factors, such as the jun protein. Such interactions are responsible for transactivation of the ds-regulatory sites known as AP-1 sites and for the glucocorticoid-mediated suppression of transcription, such as that seen in the pro-opiomelanocortin gene. A number of such specific protein interactions have been reported these interactions and their locations relative to other transcription factors transform a ubiquitous steroid hormone signal into a tissue-specific, graded cellular response. 

The transactivation domains only make their accessibility evident in the dimer bound to the HRE. It is very probable that, in this way, the spatial structure (tertiary) optimizes itself so that the contact surfaces between the receptor and the other cofactors of transcription are formed. 

Cai Y, Jin J, Tomomori-Sato C, Sato S, Sorokina 1, Parmely TJ, Conaway RC, Conaway JW (2003) Identification of new subunits of the multiprotein maimnalian TRRAP/TIP60-containing histone acetyltransferase complex. J Biol Chem 278 42733 2736 Cao X, Sudhof TC (2001) A transcriptionally [correction of transcriptively] active complex of APP with Fe65 and histone acetyltransferase Tip60. Science 293 115-120 Cao X, Sudhof TC (2004) Dissection of amyloid-beta precursor protein-dependent transcriptional transactivation. J Biol Chem 279 24601-24611... 

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