FIG. 1.

Model of the TSHR. The TSHR first appears on the plasma membrane as an intact holoreceptor. This model shows the seven transmembrane domains and the large extracellular domain. The extracellular domain consists of the 10 leucine-rich repeats in the ectodomain, which is the major site of TSH binding, and the 50 amino acid cleaved region. Reproduced with permission from Rees Smith et al. www.hotthyroidology.com/editorial_175.html. LRD, Leucine rich domain; CD, cleavage domain; TMD, transmembrane domain.