Pendrin

Solute carrier family 26 (anion exchanger), member 4
Identifiers
Symbols	SLC26A4 ; DFNB4; EVA; PDS; TDH2B
External IDs	OMIM: 605646 MGI: 1346029 HomoloGene: 20132 GeneCards: SLC26A4 Gene
Gene ontology Molecular function • secondary active sulfate transmembrane transporter activity • chloride transmembrane transporter activity • iodide transmembrane transporter activity • sulfate transmembrane transporter activity Cellular component • integral component of membrane • apical plasma membrane • brush border membrane • extracellular exosome Biological process • regulation of pH • sensory perception of sound • sulfate transport • inorganic anion transport • iodide transport • regulation of protein localization • sulfate transmembrane transport • chloride transmembrane transport Sources: Amigo / QuickGO
RNA expression pattern
More reference expression data
Orthologs
Species	Human	Mouse
Entrez	5172	23985
Ensembl	ENSG00000091137	ENSMUSG00000020651
UniProt	O43511	Q9R155
RefSeq (mRNA)	NM_000441	NM_011867
RefSeq (protein)	NP_000432	NP_035997
Location (UCSC)	Chr 7: 107.66 – 107.72 Mb	Chr 12: 31.52 – 31.56 Mb
PubMed search	[1]	[2]

Pendrin, also known as sodium-independent chloride/iodide transporter, is an antiporter anion exchanger protein that in humans is encoded by the SLC26A4 gene (solute carrier family 26, member 4). Pendrin is similar to the Band 3 transport protein found in red blood cells. Pendrin is the protein which is mutated in Pendred syndrome, which is an autosomal recessive disorder characterized by sensorineural hearing loss, goiter and a partial organification problem detectable by a positive perchlorate test.

Pendrin is responsible for mediating the electroneutral exchange of chloride (Cl⁻) for bicarbonate (HCO₃⁻) across a plasma membrane in the chloride cells of freshwater fish.

By phylogenetic analysis, pendrin has been found to be a close relative of prestin present on the hair cells or organ of corti in the inner ear. Prestin is primarily an electromechanical transducer but pendrin is an ion transporter.

Pendrin is also thought to be responsible for mediating the electroneutral exchange of chloride (Cl⁻) for bicarbonate (HCO₃⁻) across a plasma membrane in the chloride cells of freshwater fish.

Function

Pendrin is an ion exchanger found in many types of cells in the body. For example it is found in the cortical collecting duct lining cells in the kidney.

Thyroid hormone synthesis, with Pendrin seen at center between the follicular colloid and the follicular cell.

Pendrin is found at the apical (luminal) membrane of follicular cells in the thyroid gland. It transports iodide 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.

Clinical significance

Mutations in this gene are associated with Pendred syndrome, 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.

External links

• GeneReviews/NCBI/NIH/UW entry on Pendred Syndrome/DFNB4
• Description at oto.wustl.edu
• SLC26A4 protein, human at the US National Library of Medicine Medical Subject Headings (MeSH)