solute carrier family 26 member 5 (SLC26A5, prestin, PRES)

Function

• motor protein
• converts auditory stimuli to length changes in outer hair cells
• mediates sound amplification in mammalian hearing organ
• prestin is a bidirectional voltage-to-force converter; it can operate at microsecond rates
• uses cytoplasmic anions as extrinsic voltage sensors, probably chloride & bicarbonate
• after binding to a site with millimolar affinity, these anions are translocated across the membrane in response to changes in transmembrane voltage
• they move towards the extracellular surface following hyperpolarization, & towards the cytoplasmic side in response to depolarization
• anion translocation triggers conformational changes in prestin that ultimately alter its surface area in the plane of the plasma membrane
• the area decreases when the anion is near the cytoplasmic face of the membrane (short state), & increases when the anion has crossed the membrane to the outer surface (long state)
• thus prestin acts as an incomplete transporter; it swings anions across the plasma membrane, but does not allow these anions to dissociate & escape to the extracellular space

Structure

• belongs to the SLC26A/sulP transporter (TC 2.A.53) family
• contains 1 STAS domain

Compartment

• cell membrane
• lateral wall of outer hair cells

Alternative splicing

named isoforms=4

Pathology

• defects in SLC26A5 are a cause of some forms of recessive non-syndromic deafness

Pharmacology

• salicylate, an inhibitor of outer hair cell motility, acts as competitive antagonist at the prestin anion-binding site (putative)

More general terms

• solute carrier family 26 (SLC26, SLC26A)
• transmembrane 12 protein
• glycoprotein

Database

• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:3756
• OMIM: https://mirror.omim.org/entry/604943
• UniProt: http://www.uniprot.org/uniprot/P58743.html