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Molecular identity and functional properties of a novel T-type Ca2+ channel cloned from the sensory epithelia of the mouse inner ear

journal contribution
posted on 2023-06-07, 23:47 authored by Liping Nie, Jun Zhu, Michael Anne Gratton, Amy Liao, Karen J Mu, Wolfgang Nonner, Guy Richardson, Ebenezer N Yamoah
The molecular identity of non-Ca(v)1.3 channels in auditory and vestibular hair cells has remained obscure, yet the evidence in support of their roles to promote diverse Ca2+ -dependent functions is indisputable. Recently, a transient Ca(v)3.1 current that serves as a functional signature for the development and regeneration of hair cells has been identified in the chicken basilar papilla. The Ca(v)3.1 current promotes spontaneous activity of the developing hair cell, which may be essential for synapse formation. Here, we have isolated and sequenced the full-length complementary DNA of a distinct isoform of Ca(v)3.1 in the mouse inner ear. The channel is derived from alternative splicing of exon14, exon25A, exon34, and exon35. Functional expression of the channel in Xenopus oocytes yielded Ca2+ currents, which have a permeation phenotype consistent with T-type channels. However, unlike most multiion channels, the T-type channel does not exhibit the anomalous mole fraction effect, possibly reflecting comparable permeation properties of divalent cations. The Ca(v)3.1 channel was expressed in sensory and nonsensory epithelia of the inner ear. Moreover, there are profound changes in the expression levels during development. The differential expression of the channel during development and the pharmacology of the inner ear Ca(v)3.1 channel may have contributed to the difficulties associated with identification of the non-Ca(v)1.3 currents.

History

Publication status

  • Published

Journal

Journal of Neurophysiology

ISSN

0022-3077

Publisher

American Psychological Association

Issue

4

Volume

100

Page range

2287-2299

Pages

13.0

Department affiliated with

  • Neuroscience Publications

Full text available

  • No

Peer reviewed?

  • Yes

Legacy Posted Date

2012-02-06

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