Phosphatidylinositol-4,5-Bisphosphate Regulates Mechanotransduction and Adaptation in Hair Cells

Abstract

In the inner ear, hair cells detect not only sounds but also acceleration with their mechanotransduction apparatus. In this study, I demonstrate that transduction and adaptation require phosphatidylinositol-4,5-bisphosphate (PIP₂) for normal kinetics. PIP₂ has a striking distribution in hair cells, being excluded from the basal region of hair bundles and apical surfaces of bullfrog saccular hair cells. The depletion of PIP₂ by the inhibition of phosphatidylinositol 4-kinase or sequestration by an aminoglycoside reduces the rate of fast and slow adaptation, and also causes a loss in transduction currents, suggesting that PIP₂ plays an essential role in hair cell adaptation and transduction.