Pendrin
Encyclopedia
Pendrin also known as sodium-independent chloride/iodide transporter is a protein
that in humans is encoded by the SLC26A4 gene
(solute carrier family 26, member 4).
Pendrin is found at the apical (luminal
) membrane of follicular cell
s in the thyroid gland
. It transports iodine from the cytoplasm to the follicle lumen. Its activity is necessary for production of thyroid hormone
.
Pendrin is also found in the cells of the inner ear, where its function is not well understood.
, the most common form of syndromic deafness, an autosomal-recessive disease. Pendred syndrome is also characterized by hypothyroidism
. SLC26A4 is highly homologous to the SLC26A3
gene; they have similar genomic structures and this gene is located 3' of the SLC26A3 gene. The encoded protein has homology to sulfate transporters.
Another little-understood role of pendrin is in airway hyperreactivity and inflammation
, as during asthma attacks and allergic reactions. Expression of pendrin in the lung increases in response to allergens and high concentrations of IL-13
, and overexpression of pendrin results in airway inflammation, hyperreactivity, and increased mucus production. These symptoms could result from pendrin's effects on ion concentration in the airway surface liquid, possibly causing the liquid to be less hydrated.
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
that in humans is encoded by the SLC26A4 gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
(solute carrier family 26, member 4).
Function
Pendrin is an ion exchanger found in the cortical collecting duct.Pendrin is found at the apical (luminal
Lumen (anatomy)
A lumen in biology is the inside space of a tubular structure, such as an artery or intestine...
) membrane of follicular cell
Thyroid epithelial cell
Thyroid epithelial cells are cells in the thyroid gland that are responsible for the production and secretion of thyroid hormones, that is, thyroxine and triiodothyronine .-Function:...
s in the thyroid gland
Thyroid
The thyroid gland or simply, the thyroid , in vertebrate anatomy, is one of the largest endocrine glands. The thyroid gland is found in the neck, below the thyroid cartilage...
. It transports iodine from the cytoplasm to the follicle lumen. Its activity is necessary for production of thyroid hormone
Thyroid hormone
The thyroid hormones, thyroxine and triiodothyronine , are tyrosine-based hormones produced by the thyroid gland primarily responsible for regulation of metabolism. An important component in the synthesis of thyroid hormones is iodine. The major form of thyroid hormone in the blood is thyroxine ,...
.
Pendrin is also found in the cells of the inner ear, where its function is not well understood.
Clinical significance
Mutations in this gene are associated with Pendred syndromePendred syndrome
Pendred syndrome or Pendred disease is a genetic disorder leading to congenital bilateral sensorineural hearing loss and goitre with occasional hypothyroidism . There is no specific treatment, other than supportive measures for the hearing loss and thyroid hormone supplementation in case of...
, the most common form of syndromic deafness, an autosomal-recessive disease. Pendred syndrome is also characterized by hypothyroidism
Hypothyroidism
Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or...
. SLC26A4 is highly homologous to the SLC26A3
SLC26A3
Solute carrier family 26, member 3, also known as SLC26A3, or DRA is a human gene.-Further reading:...
gene; they have similar genomic structures and this gene is located 3' of the SLC26A3 gene. The encoded protein has homology to sulfate transporters.
Another little-understood role of pendrin is in airway hyperreactivity and inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
, as during asthma attacks and allergic reactions. Expression of pendrin in the lung increases in response to allergens and high concentrations of IL-13
Interleukin 13
Interleukin 13 is a protein that in humans is encoded by the IL13 gene. IL-13 is cytokine secreted by many cell types, but especially T helper type 2 cells, that is a mediator of allergic inflammation and disease.-Functions:...
, and overexpression of pendrin results in airway inflammation, hyperreactivity, and increased mucus production. These symptoms could result from pendrin's effects on ion concentration in the airway surface liquid, possibly causing the liquid to be less hydrated.