title: Hair cells, plasma membrane Ca²⁺ ATPase and deafness.
abstract: Hearing relies on the ability of the inner ear to convert sound waves into electrical signals. The main actors in this process are hair cells. Their stereocilia contain a number of specific proteins and a scaffold of actin molecules. They are organized in bundles by tip-link filaments composed of cadherin 23 and protocadherin 15. The bundle is deflected by sound waves leading to the opening of mechano-transduction channels and to the influx of K(+) and Ca(2+) into the stereocilia. Cadherin 23 and the plasma membrane calcium ATPase isoform 2 (PMCA2) are defective in human and murine cases of deafness. While the involvement of cadherin 23 in deafness/hearing could be expected due to its structural role in the tip-links, that of PMCA2 has been discovered only recently. This review will summarize the structural and functional characteristics of hair cells, focusing on the proteins whose mutations may lead to a deafness phenotype.
authors.affiliation: Venetian Institute of Molecular Medicine, Via G. Orus, 2, 35129 Padua, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Giacomello
authors.forename: Agnese
authors.initials: A
authors.lastname: De Mario
authors.forename: Simona
authors.initials: S
authors.lastname: Primerano
authors.forename: Marisa
authors.initials: M
authors.lastname: Brini
authors.forename: Ernesto
authors.initials: E
authors.lastname: Carafoli
mesh_terms: D000818:Animals; D000070585:Cadherin Related Proteins; D015820:Cadherins / Q000235:genetics* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism; D003638:Deafness / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D007758:Ear, Inner / Q000378:metabolism / Q000503:physiopathology; D006198:Hair Cells, Auditory / Q000378:metabolism* / Q000473:pathology; D006309:Hearing / Q000502:physiology; D006801:Humans; D040542:Mechanotransduction, Cellular; D051379:Mice; D009154:Mutation; D053499:Plasma Membrane Calcium-Transporting ATPases / Q000235:genetics* / Q000378:metabolism; D059547:Stereocilia / Q000378:metabolism / Q000473:pathology
chemical_list: C442480:CDH23 protein, human; D000070585:Cadherin Related Proteins; D015820:Cadherins; D053499:Plasma Membrane Calcium-Transporting ATPases; D002118:Calcium