Essay On Nuclear Receptors

Nuclear receptors are a class of receptors that have the ability to bind ligands, steroid and thyroid hormones, in order to mediate the expression of specific genes in a cell***. There are two types of nuclear receptors in the family, type one and type two. Type one receptors require a ligand to be bound to the receptor so activation can be initiated** by a conformational change of the ligand, travel to the nucleus and associate to inverted repeat hormone response elements in DNA. Type two receptors mostly are kept in the nucleus of the cell that will be focused on and do not require a ligand to be bound to them in order to become activated. When type II receptors bind to direct DNA repeats, they do so as heterodimers of the specific dimer as well as with RXR, while type one receptors are homodimers binding to DNA’s inverted repeats.

All nuclear receptors have a distinctive feature in which classifies them separately to other receptors in the body. This distinctive feature is the nuclear receptors’ binding domains, of which there are two. The first binding domain is the zinc finger-based DNA binding domain which has a unique function in which it couples the hormone response

Steroid hormones are important biochemically for their ability to activate transcription in specific DNA binding sites. Steroid hormones are type I nuclear receptors, in that they require a ligand to be bound to them in order to be activated. Steroid hormones are released from the testes, ovaries and adrenal glands. An example of one is estrogen. Estrogen refers to a group of various hormones, including estradiol, estriol and estrone, of which their main role is of as a sexual and reproductive maturation hormone in females. Estrogen binds to the estrogen receptor to activate it. Like there are many hormones in the estrogen family, there are two types of nuclear estrogen receptors, estrogen receptor α (ERα) and estrogen receptor β