2 effects nuclear protein binding

Patiemo SR, Costa M. 1987. Effects of nickel(II) on nuclear protein binding to DNA in intact mammalian cells. Cancer Biochem Biophys 9 113-126. 

Triiodothyronine (3, 5,3-L-triiodothyronine, T3) is a thyroid hormone. It is producedby outer ring deiodination of thyroxine (T4) in peripheral tissues. The biologic activity of T3 is 3-8 times higher than that of T4. T3 is 99.7% protein-bound and is effective in its free non-protein-bound form. The half-life of triiodothyronine is about 19 h. The daily tur nover of T3 is 75%. Triiodothyronine acts via nuclear receptor binding with subsequent induction of protein synthesis. Effects of thyroid hormones are apparent in almost all organ systems. They include effects on the basal metabolic rate and the metabolisms of proteins, lipids and carbohydrates. 

The oncogene of the FBJ murine osteosarcoma virus (fos) codes for a related nuclear protein that participates in transcriptional regulation. In human fibroblasts the fos protein is mostly associated with c-jun. The fos-jun complex binds specifically to DNA. Since fos alone does not show specific DNA binding, it is believed that jun is responsible for this affinity. Although jun can form homodimers that bind to DNA, the heterodimers formed between fos and jun show a greater affinity. The heterodimers are also more effective in transcription activation therefore the heterodimer is probably the functionally relevant state of the jun and fos proteins. 

Matthyssee and Phillips (20) isolated two nuclear proteins, from tobacco cells, that bound specifically to 2,4-D. Receptor proteins for auxins, kinetins, and GA have been found (21). Sub-cellular fractions from bean leaves were recently shown to bind abscisic acid (22). Preliminary experiments (22) indicated that maximum ABA binding activity coincides with the activities of membrane-bound Mg -dependent, K+-stimulated ATPase and glucan synthetase. Table I of Biswas and Roy (21) lists hormone receptor proteins reported in plant tissue. For a protein to qualify as a receptor molecule, it should have a high stereo-specific binding capacity (Kd 10 6 to 10 SM) for its particular hormone. In com coleoptiles, both IAA and NAA are equally effective in inducing cell elongations fractions of plasma membrane and endoplasmic reticular membrane contain receptor proteins with Kd values of 10 M to 10 M for auxins (5, 18). When one considers procedural... 

Additional evidence for the cardioprotective role of estrogens is derived from cell models of simulated ischemia. Treatment with 17fS-estradiol enhanced cell survival after hypoxia-reoxygenation in cardiomyocytes from adult female rats. In addition, estrogens activated NF-kB and HSF1 and increased the expression of heat shock protein 72. Decoy-mediated blockade of nuclear HSF1 binding preserved the cardioprotective effect of 17 3-estradiol while transfection with NFkB decoy prevented the increase in heat shock protein 72 and abolished protection.10... 

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