The thyrotropin receptor (or TSH receptor) is a receptor (and associated protein) that responds to
thyroid-stimulating hormone
Thyroid-stimulating hormone (also known as thyrotropin, thyrotropic hormone, or abbreviated TSH) is a pituitary hormone that stimulates the thyroid gland to produce thyroxine (T4), and then triiodothyronine (T3) which stimulates the metabolism o ...
(also known as "thyrotropin") and stimulates the production of
thyroxine
File:Thyroid_system.svg, upright=1.5, The thyroid system of the thyroid hormones T3 and T4
rect 376 268 820 433 Thyroid-stimulating hormone
rect 411 200 849 266 Thyrotropin-releasing hormone
rect 297 168 502 200 Hypothalamus
rect 66 216 386 25 ...
(T4) and
triiodothyronine
Triiodothyronine, also known as T3, is a thyroid hormone. It affects almost every physiological process in the body, including growth and development, metabolism, body temperature, and heart rate.
Production of T3 and its prohormone thyroxine ...
(T3). The TSH receptor is a member of the
G protein-coupled receptor
G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptors, and G protein-linked receptors (GPLR), form a large group of evolutionarily-related p ...
superfamily of
integral membrane protein
An integral, or intrinsic, membrane protein (IMP) is a type of membrane protein that is permanently attached to the biological membrane. All ''transmembrane proteins'' are IMPs, but not all IMPs are transmembrane proteins. IMPs comprise a signif ...
s
and is coupled to the
Gs protein.
It is primarily found on the surface of the
thyroid epithelial cell
Thyroid follicular cells (also called thyroid epithelial cells or thyrocytes) are the major cell type in the thyroid gland, and are responsible for the production and secretion of the thyroid hormones thyroxine (T4) and triiodothyronine (T3). They ...
s, but also found on adipose tissue and fibroblasts. The latter explains the reason of the myxedema finding during Graves disease. In addition, it has also been found to be expressed in the anterior pituitary gland, hypothalamus and kidneys. Its presence in the anterior pituitary gland may be involved in mediating the paracrine signaling feedback inhibition of thyrotropin along the hypothalamus-pituitary-thyroid axis.
Function
Upon binding circulating TSH, a G-protein signal cascade activates adenylyl cyclase and intracellular levels of cAMP rise. cAMP activates all functional aspects of the thyroid cell, including iodine pumping;
thyroglobulin
Thyroglobulin (Tg) is a 660 kDa, dimeric glycoprotein produced by the follicular cells of the thyroid and used entirely within the thyroid gland. Tg is secreted and accumulated at hundreds of grams per litre in the extracellular compartment ...
synthesis, iodination, endocytosis, and proteolysis;
thyroid peroxidase
Thyroid peroxidase, also called thyroperoxidase (TPO) or iodide peroxidase, is an enzyme expressed mainly in the thyroid where it is secreted into colloid. Thyroid peroxidase oxidizes iodide ions to form iodine atoms for addition onto tyrosine r ...
activity; and hormone release. TSHR is involved in regulating seasonal reproduction in vertebrates.
See also
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Graves' disease
Graves' disease (german: Morbus Basedow), also known as toxic diffuse goiter, is an autoimmune disease that affects the thyroid. It frequently results in and is the most common cause of hyperthyroidism. It also often results in an enlarged thyro ...
References
Further reading
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External links
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SSFA-GPHR: Sequence Structure Function Analysis of Glycoprotein Hormone ReceptorsGRIS: Glycoprotein-hormone Receptor Information System*
{{Neuropeptide receptors
G protein-coupled receptors
Thyroid