Hormone receptor

A hormone receptor is a receptor molecule that binds to a specific hormone. Receptors for peptide hormones tend to be cell surface receptors (built into the plasma membrane of cells, thus trans membrane), whereas receptors for steroid hormones are usually found within the cytoplasm (nuclear receptors). Upon hormone binding, the receptor can initiate multiple signaling pathways which ultimately lead to changes in the behavior of the target cells.

Classification

Receptors for water-soluble hormones

Water-soluble hormones include glycoproteins, catecholamines, and peptide hormones composed of polypeptides, e.g. thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone and insulin. These molecules are not lipid-soluble and therefore cannot diffuse through cell membranes. Consequently, receptors for peptide hormones are located on the plasma membrane.

The main two types of transmembrane receptor hormone receptor are the G-protein-coupled receptors and the enzyme-linked receptors. These receptors generally function via intracellular second messengers, including cyclic AMP (cAMP), cyclic GMP (cGMP), inositol 1,4,5-trisphosphate (IP3) and the calcium (Ca2+)-calmodulin system.

Receptors for lipid-soluble hormones

Steroid hormone receptors and related receptors are generally soluble proteins that function through gene activation. Their response elements are DNA sequences (promoters) that are bound by the complex of the steroid bound to its receptor. The receptors themselves are zinc-finger proteins.[1] These receptors include those for glucocorticoids (glucocorticoid receptors), estrogens (estrogen receptors), androgens (androgen receptors), thyroid hormone (T3) (thyroid hormone receptors), calcitriol (the active form of vitamin D) (calcitriol receptors), and the retinoids (vitamin A) (retinoid receptors).

List of hormone receptors

This list is incomplete; you can help by expanding it.

For some of these classes, in any given species (such as, for example, humans), there is a single molecule encoded by a single gene; in other cases, there are several molecules in the class.

References


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