Thyroid Hormone Receptor Mutations in Cancer and Resistance to Thyroid Hormone: Perspective and Prognosis

Figure 1

Regulation of thyroid hormone synthesis and activity. TRH is produced in the hypothalamus (shown in pink) and stimulates the anterior pituitary (shown in green) to create TSH, which stimulates the follicular cells of the thyroid gland (purple) to produce T3 and T4. T3 and T4 circulate through the blood to the peripheral tissues (see box at right), where they are transported across the cell membrane into the cytoplasm by MCT8/MCT10 (green oval). T4 can be converted to T3 by deiodinase type 1 and deiodinase type 2 (DIO1/2, gray sphere). Both T3 and T4 can enter the nucleus and regulate TR activity. TR is shown here as a yellow sphere bound to DNA. On most sites, TRs can dimerize, either as homodimers or as heterodimers, with another nuclear receptor partner (NR, dark gray sphere).