PMID:17050716

Citation	Phillips, KR, Tong, S, Goodyear, R, Richardson, GP and Cyr, JL (2006) Stereociliary myosin-1c receptors are sensitive to calcium chelation and absent from cadherin 23 mutant mice. J. Neurosci. 26:10777-88
Abstract	The identities of some of the constituents of the hair-cell transduction apparatus have been elucidated only recently. The molecular motor myosin-1c (Myo1c) functions in adaptation of the hair-cell response to sustained mechanical stimuli and is therefore an integral part of the transduction complex. Recent data indicate that Myo1c interacts in vitro with two other molecules proposed to be important for transduction: cadherin 23 (Cdh23), a candidate for the stereociliary tip link, and phosphatidylinositol 4,5-bisphosphate (PIP2), which is abundant in the membranes of hair-cell stereocilia. It is not known, however, whether these interactions occur in hair cells. Using an in situ binding assay on saccular hair cells, we demonstrated previously that Myo1c interacts with molecules at stereociliary tips, the site of transduction, through sequences contained within its calmodulin (CaM)-binding neck domain, which can bind up to four CaM molecules. In the current study, we identify the second CaM-binding IQ domain as a region of Myo1c that mediates CaM-sensitive binding to stereociliary tips and to PIP2 immobilized on a solid support. Binding of Myo1c to stereociliary tips of cochlear and vestibular hair cells is disrupted by treatments that break tip links. In addition, Myo1c does not bind to stereocilia from mice whose hair cells lack Cdh23 protein despite the presence of PIP2 in the stereociliary membranes. Collectively, our data suggest that Myo1c and Cdh23 interact at the tips of hair-cell stereocilia and that this interaction is modulated by CaM.
Links	PubMed Online version:10.1523/JNEUROSCI.1847-06.2006
Keywords	Animals; Cadherins/genetics; Cadherins/metabolism; Calcium/metabolism; Calmodulin/physiology; Cattle; Cells, Cultured; Chelating Agents/metabolism; Cilia/drug effects; Cilia/metabolism; Hair Cells, Auditory/drug effects; Hair Cells, Auditory/metabolism; Insects; Mice; Mice, Neurologic Mutants; Myosin Type I/deficiency; Myosin Type I/genetics; Myosin Type I/metabolism; Protein Binding; Rana catesbeiana
edit table

Annotations

Gene product	Qualifier	GO ID	GO term name	Evidence Code	with/from	Aspect	Notes	Status
edit table

References

See Help:References for how to manage references in GONUTS.