DOI: 10.5061/dryad.0vt4b8h5r
title: Data from: LHFPL5 is a key element to the gating spring of cochlear hair cells: comparison of mechanotransduction channel activation in presence or absence of LHFPL5

description: During auditory transduction, sound-evoked vibrations of the hair cell
 stereociliary bundles open mechanotransducer (MET) ion channels via tip
 links extending from one stereocilium to its neighbor. How tension in the
 tip link is delivered to the channel is not fully understood. 
 The MET channel comprises a pore-forming subunit, transmembrane
 channel-like protein (TMC1 or TMC2), aided by several accessory proteins,
 including LHFPL5 (lipoma HMGIC fusion partner-like 5). We investigated the
 role of LHFPL5 in transduction by comparing MET channel activation in
 outer hair cells of Lhfpl5-/- knockout mice with those in Lhfpl5+/-
 heterozygotes. The 10-90 percent working range of transduction in Tmc1+/+;
 Lhfpl5+/- was 52 nm, from which the single-channel gating force, Z was
 evaluated as 0.34 pN. However, in Tmc1+/+; Lhfpl5‑/- mice, the working
 range increased to 123 nm and Z more than halved to 0.13 pN, indicating
 reduced sensitivity. Tip link tension is thought to activate the channel
 via a gating spring, whose stiffness is inferred from the stiffness change
 on tip link destruction. The gating stiffness was ~40 percent of the total
 bundle stiffness in wild-type but was virtually abolished in Lhfpl5-/-,
 implicating LHFPL5 as a principal component of the gating
 spring.  The mutation Tmc1 p.D569N reduced the LHFPL5
 immunolabeling in the stereocilia and like Lhfpl5-/- doubled the MET
 working range but other deafness mutations had no effect on the dynamic
 range.  We conclude that tip-link tension is transmitted to the
 channel primarily via LHFPL5; residual activation without LHFPL5 may occur
 by direct interaction between PCDH15 and TMC1.
description: MET currents were recorded from outer hair cells (OHCs) in
 isolated organs of Corti of mice between P2 and P7. All whole cell
 recordings were performed at room temperature, ~23ºC.
 All data included in the published article are presented in an
 Excel file, giving all values obtained to construct the mean +/- 1 SD, for
 every recorded hair cell in all the different mouse genotypes used in the
 study. The Excel file is organized in 3 sheets,
 describing the MET current bundle displacement results, hair bundle
 stiffness data, and the hair bundle height measurements.
 Stereociliary bundles were stimulated with a fluid jet, and the
 bundle deflections calibrated by projecting the bundle image onto a pair
 of photodiodes and measuring the change in photocurrent. The Excel file
 gives all values obtained for the relationship between the MET current, I,
 and bundle displacement, X. The I-X relationship was fitted with a
 Boltzmann equation: I = I<sub>MAX</sub> /(1 +
 exp((X<sub>O </sub>-X)/X<sub>S</sub>), where
 I<sub>MAX </sub>is the maximum current, X<sub>O
 </sub>the half-saturating displacement and X<sub>S</sub>
 the slope factor.  The 10 to 90 percent working range of transduction (WR)
 is 4.4*X<sub>S.</sub> Hair bundle stiffness
 was determined by calibrating the force generated by the fluid jet against
 a flexible glass fiber of 1 mN/m and plotting against bundle displacement.
 The Excel file shows all hair bundle stiffness measurements used to
 construct our mean +/- SD, for all cells and mouse genotype used in the
 study. Bundle height measurement was performed on
 solitary outer hair cells and the hair bundle length was measured from the
 root to the tip of the longest stereocilia.
description: # Data from: LHFPL5 is a key element to the gating spring of cochlear hair
 cells: comparison of mechanotransduction channel activation properties in
 presence or absence of LHFPL5
 ## Description of the data
 and file structure Data are readable using Excel software. Data are
 presented in one single excel file: Lhfpl5_data.xlsx. Three sheets are
 present and related to the experimental topic: **IX Working Range** :
 Values summarized all data collected for all outer hair cells recordings,
 used in the published manuscript. WR stands for working range, Imx is the
 maximum mechanotransduction (MET) current and the age of the animal is
 given for each cell recorded. The different colors in the spreadsheet
 reflect the genotype of the mice recorded. All recording were performed on
 apical outer hair cells (OHC) **Stiffness:** Values summarized all data
 collected for all outer hair cells recordings used in our study. The
 different colors in the spreadsheet reflect the mice genotype. Hair bundle
 stiffness (KHB) was defined in control condition (no treatment) and after
 breaking the tip links (on the same cell). The deducted gating spring
 stiffness (K GS) was given. Age of the animal is given for each recorded
 cells. NA (not applicable) represents a lack of measurement or a loss of
 the recording. **Lipids experiments:** These data summarized the effect of
 lipid modulation on working range (WR) and MET max current (Imx).
 Measurements were performed at two times, before 5 minutes (control) and
 after the action of the drug (20-30 minutes). Each color represent a
 different lipid modulator. The concentration of each modulator is listed
 on the spreadsheet. Abbreviations: MβCD (methyl-β-cyclodextrin),
 Cholesterol (water-soluble cholesterol), DHA (Sodium docosahexanoic acid)
 **Bundle Height:** The bundle height was determined on isolated outer hair
 cells. Age and genotype of the animal are given for each measurement.