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

The transmembrane motor protein prestin is thought to underlie outer hair cell (OHC) motility. Prestin expressed in non-auditory cells confers OHC-like electrical characteristics to the cell membrane, including the generation of gating-like currents (or non-linear capacitance), whose voltage dependence is susceptible to membrane tension and initial voltage conditions. Here we report that prestin's voltage sensitivity is, like that of the native motor, markedly temperature dependent. Prestin-transfected HEK cells were whole-cell voltage clamped while temperature was varied from 10-35 degrees C. V(pkcm), the voltage at peak capacitance, reversibly and linearly shifted to depolarized levels with increasing temperatures, while peak capacitance also increased, but with significant hysteresis upon recooling. Mathematical modeling 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 plasma membrane at higher temperatures.