Nuclear hormone receptor examples

An example of the complexity involved in the regulation of nuclear hormone receptors is shown in the case of the ER in the liver. Its synthesis is induced by estradiol, growth hormone, thyroid hormones, and glucocorticoids. 

Nuclear Hormone Receptors. Certain hormones interact directly with hormonal receptors that are located on the chromatin within the cell nucleus (see Fig. 28-2).3 Thyroid hormones (T3 and T4) are a primary example of hormones that bind directly to nuclear receptors.29 After binding, thyroid hormones invoke a series of changes similar to those caused by the steroid-cytosolic receptor complex that is, the nucleus begins to transcribe messenger RNA, which is ultimately translated into specific proteins. In the case of the thyroid hormones, these new proteins usually alter the cell s metabolism. Thyroid hormones are discussed in more detail in Chapter 31. 

The translocation of a nuclear hormone receptor to the nucleus is an early stage of receptor activation. A number of assay technologies can detect this nuclear translocation event. For example, using... 

The activation or inhibition of nuclear hormone receptors by synthetic androgens, with a readout (way) downstream of transcriptional regulation such as muscle growth or inhibition of sperm production (a highly educational example, isn t it). 

Here we will focus on current progress in structural analyses of nuclear hormone receptors, and how these proteins interact with their ligands, both natural and pharmaceutical. We will provide first a general overview of nuclear receptors and then using several nuclear receptors as examples, we will discuss the receptor-ligand specificity throughout the nuclear receptor... 

Figure 2 Nuclear hormone receptor structure and ligands, (a) The functional domains of nuclear hormone receptors. They act as either homodimers or heterodimers with a ligand binding domain and a DNA binding domain that are separated by a linker sequence, (b) The conformational change in helix 12 when ligand binding occurs (61, 62). All-trans retinoic acid is shown behind helix 12. (c) Examples of synthetic ligands for estrogen receptor (SERMs) and thyroid hormone receptor (Thyromimetics).

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