Lateral wall protein content mediates alterations in cochlear outer hair cell mechanics before and after hearing onset

Heather Jensen-Smith, Richard J. Hallworth

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Specialized outer hair cells (OHCs) housed within the mammalian cochlea exhibit active, nonlinear, mechanical responses to auditory stimulation termed electromotility. The extraordinary frequency resolution capacity of the cochlea requires an exquisitely equilibrated mechanical system of sensory and supporting cells. OHC electromotile length change, stiffness, and force generation are responsible for a 100-fold increase in hearing sensitivity by augmenting vibrational input to non-motile sensory inner hair cells. Characterization of OHC mechanics is crucial for understanding and ultimately preventing permanent functional deficits due to overstimulation or as a consequence of various cochlear pathologies. The OHCs' major structural assembly is a highly-specialized lateral wall. The lateral wall consists of three structures; a plasma membrane highly-enriched with the motor-protein prestin, an actin-spectrin cortical lattice, and one or more layers of subsurface cisternae. Technical difficulties in independently manipulating each lateral wall constituent have constrained previous attempts to analyze the determinants of OHCs' mechanical properties. Temporal separations in the accumulation of each lateral wall constituent during postnatal development permit associations between lateral wall structure and OHC mechanics. We compared developing and adult gerbil OHC axial stiffness using calibrated glass fibers. Alterations in each lateral wall component and OHC stiffness were correlated as a function of age. Reduced F-actin labeling was correlated with reduced OHC stiffness before hearing onset. Prestin incorporation into the PM was correlated with increased OHC stiffness at hearing onset. Our data indicate lateral wall F-actin and prestin are the primary determinants of OHC mechanical properties before and after hearing onset, respectively.

Original languageEnglish
Pages (from-to)705-717
Number of pages13
JournalCell Motility and the Cytoskeleton
Volume64
Issue number9
DOIs
StatePublished - Sep 2007

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Outer Auditory Hair Cells
Mechanics
Hearing
Proteins
Cochlea
Actins
Inner Auditory Hair Cells
Acoustic Stimulation
Spectrin
Gerbillinae

All Science Journal Classification (ASJC) codes

  • Cell Biology

Cite this

Lateral wall protein content mediates alterations in cochlear outer hair cell mechanics before and after hearing onset. / Jensen-Smith, Heather; Hallworth, Richard J.

In: Cell Motility and the Cytoskeleton, Vol. 64, No. 9, 09.2007, p. 705-717.

Research output: Contribution to journalArticle

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