Elfpplflevf Edqev 410

figure 6-19 Schematic model of the structural domains of the thyroid receptor as determined via X-ray crystallographic techniques. The ligand binding domain of the thyroid receptor is composed of 255 amino acids which represent residues 156-410 in the intact thyroid receptor. This figure illustrates the 12 a-helices, designated Hi to Hi2 and the 4 /3-strands, designated S, to S4 which comprise the secondary structure. The amino acid residues at the beginning and at the end of each a-helix are indicated using the one-letter code (see Appendix E). The inset box provides the primary amino acid sequence of the thyroid c*i receptor ligand binding domain. The actual three-dimensional ribbon structure of the rat a! thyroid receptor ligand binding domain with a thyroid hormone agonist is shown on the front cover of this book; it begins with the red color for the a-helix, at the N-terminus and progresses down the colors of the visible spectrum to the royal blue color for a-helix]2 at the carboxy terminus. The hormone (purple) is depicted as a space-filling model. [This figure was modified with permission from Fig. 1 of Wagner, R. L., Apriletti, J. W., McGrath, M. E., West, B. L., Baxter, J. D., and Fletterick, R. J. (1995). A structural role for hormone in the thyroid hormone receptor. Nature 378, 690-697.]

the family of thyroid receptors. This family can utilize various thyroid receptor isoforms (Figure 6-17) as well as unliganded or liganded forms of homo- and hetero-dimers to achieve specificity with regard to the selection of the genes to be regulated.

Table 6-6 presents a selected summary of the many genes known to be either up-regulated or down-

regulated by thyroxine and the thyroid receptor. Careful inspection of the table will reveal the wide array of biological systems that are subject to the influence of thyroid hormonal status. Some selective examples include the following: intermediary metabolism enzymes (malic enzyme, phosphoenolpyruvate carboxy kinase, 6-phosphogluconate dehydrogenase), choles-

TABLE 6-5 Examples of Genes Up-Regulated or Down-Regulated by Thyroid Hormones"

Cure Tennis Elbow Without Surgery

Cure Tennis Elbow Without Surgery

Everything you wanted to know about. How To Cure Tennis Elbow. Are you an athlete who suffers from tennis elbow? Contrary to popular opinion, most people who suffer from tennis elbow do not even play tennis. They get this condition, which is a torn tendon in the elbow, from the strain of using the same motions with the arm, repeatedly. If you have tennis elbow, you understand how the pain can disrupt your day.

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