Regulation of cellular calcium in vestibular supporting cells by otopetrin 1

Euysoo Kim, Krzysztof L. Hyrc, Judith Speck, Yunxia W. Lundberg, Felipe T. Salles, Bechara Kachar, Mark P. Goldberg, Mark E. Warchol, David M. Ornitz

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


Otopetrin 1 (OTOP1) is a multitransmembrane domain protein, which is essential for mineralization of otoconia, the calcium carbonate biominerals required for vestibular function, and the normal sensation of gravity. The mechanism driving mineralization of otoconia is poorly understood, but it has been proposed that supporting cells and a mechanism to maintain high concentrations of calcium are critical. Using Otop1 knockout mice and a utricular epithelial organ culture system, we show that OTOP1 is expressed at the apex of supporting cells and functions to increase cytosolic calcium in response to purinergic agonists, such as adenosine 5'-triphosphate (ATP). This is achieved by blocking mobilization of calcium from intracellular stores in an extracellular calciumdependent manner and by mediating influx of extracellular calcium. These data support a model in which OTOP1 acts as a sensor of the extracellular calcium concentration near supporting cells and responds to ATP in the endolymph to increase intracellular calcium levels during otoconia mineralization.

Original languageEnglish (US)
Pages (from-to)3439-3450
Number of pages12
JournalJournal of neurophysiology
Issue number6
StatePublished - Dec 2010

ASJC Scopus subject areas

  • General Neuroscience
  • Physiology


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