Temperature dependence of non-linear capacitance in human embryonic kidneycells transfected with prestin, the outer hair cell motor protein

The transmembrane motor protein prestin is thought to underlie outer hair c ell (OHC) motility. Prestin expressed in nonauditory cells confers OHC-like electrical characteristics to the cell membrane, including the generation of gating-like currents (or non-linear capacitance), whose voltage dependen ce is susceptible to membrane tension and initial voltage conditions. Here we report that prestin's voltage sensitivity is, like that of the native mo tor, markedly temperature dependent. Prestin-transfected HEK cells were who le-cell voltage clamped while temperature was varied from 10-35 degreesC. V -pkcm, the voltage at peak capacitance, reversibly and linearly shifted to depolarized levels with increasing temperatures, while peak capacitance als o increased, but with significant hysteresis upon recooling. Mathematical m odeling suggests that this increase may be due to a charged voltage sensor having a wider range of movement through or larger unit charge within the p lasma membrane at higher temperatures. (C) 2001 Elsevier Science Ireland Lt d. All rights reserved.