Transactivating factor

The expression of the ptx genes requires a transactivating factor, named BvgA. This transactivator is part of a two-component system composed of the sensor BvgS and the activator BvgA (for review, see Uhl and /Vliller, 1995). PTX is coordinately produced together with other 6. pertussis virulence factors. All known virulence factors are under the control of the same BvgA/S two-component system. 

The antiinflammatory effects of statins likely result from their ability to inhibit the formation of mevalonic acid. Downstream products of this molecule include not only the end product, cholesterol, but also several isoprenoid intermediates that covalently modify ( pre-nylate ) certain key intracellular signaling molecules. Statin treatment reduces leukocyte adhesion, accumulation of macrophages, MMPs, tissue factor, and other proinflammatory mediators. By acting on the MHC class II transactivator (CIITA), statins also interfere with antigen presentation and subsequent T-cell activation. Statin treatment can also limit platelet activation in some assays as well. All these results support the concept that in addition to their favorable effect on the lipid profile, statins can also exert an array of antiinflammatory and immunomodulatory actions. 

Chromatin remodeling, transcription factor modification by various enzyme activities, and the communication between the nuclear receptors and the basal transcription apparatus are accomplished by protein-protein interactions with one or more of a class of coregulator molecules. The number of these coregulator molecules now exceeds 100, not counting species variations and splice variants. The first of these to be described was the CREB-binding protein, CBP. CBP, through an amino terminal domain, binds to phosphorylated serine 137 of CREB and mediates transactivation in response to cAMP. It thus is described as a coactivator. CBP and... 

Other HIV proteins include regulator of viral expression (Rev), negative effectors (Nef), viral protein R (Vpr), viral protein U (Vpu), viral infectivity factor (Vif) and transactivator protein (Tat). These proteins are instrumental in viral mRNA expression, viral replication and transactivation, viral release and maturation, viral infection, and maintenance of viral transcript activation and expression, respectively (Tripathi and Agrawal 2007). 

Cabioglu N, Summy J, Miller C, et al. CXCL-12/stromal cell-derived factor-la transactivates HER2-neu in breast cancer cells by a novel pathway involving src kinase activation. Cancer Res 2005 65 6493-6497. 

Leserer, M., Gschwind, A., and Ullrich, A. 2000. Epidermal growth factor receptor signal transactivation. IUBMB Life 49(5), 405-430. 

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 participation of the nuclear receptors in the machinery of gene transcription takes place by means of specific domains of the molecule known as transactivators (abbreviation for transcription activators). These are made up of sequences of amino acids that interact by means of protein-protein contacts with other transcription factors. The artificial alteration of these sequences has as a consequence the inability of the hormone to induce gene expression (Beato et al. 1996 Klug et al. 1987 Lones et al. 1995). 

Filardo EJ (2002) Epidermal growth factor receptor (EGFR) transactivation by estrogen via the G-protein-coupled receptor, GPR30 a novel signaling pathway with potential significance for breast cancer. J Steroid Biochem Mol Biol 80 231... 

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