Steroid hormones are able to penetrate the plasma membrane following which they bind to specific receptors inside the cell termed intracellular or nuclear receptors. If a cell line that normally were able to respond to the presence of a particular steroid hormone sustained a mutation in the ligandbinding domain of the receptor, which of the following processes would most likely be impaired?

Question

Quizplus · Accepted Answer

The mutation in the ligand-binding domain of the receptor would impair the receptor's ability to bind the steroid hormone, which in turn would affect the transcription of specific genes that are normally regulated by the hormone-receptor complex.  Steroid hormones are lipophilic and hence freely penetrate the plasma membrane of all cells. Within target cells, steroid hormones interact with specific receptors. These receptor proteins are composed of 2 domains: a hormone-binding domain and a DNA-binding domain. Following hormonereceptor interaction, the complex is activated and enters the nucleus. The DNA-binding domain of the receptor interacts with specific nucleotide sequences termed hormone response elements (HREs). The binding of steroid-receptor complexes to HREs results in an altered rate of transcription of the associated gene(s). The effects of steroid-receptor complexes on specific target genes can be either stimulatory or inhibitory with respect to the rate of transcription.

Steroid Hormones Are Able to Penetrate the Plasma Membrane Following