Turnover and Activity-Dependent Transcriptional Control of NompC (=TRPN1) in the <i>Drosophila</i> Ear

Abstract

Across their lives, biological sensors maintain a near-constant functional output despite a plethora of exogenous and endogenous perturbations. This sensory homeostasis is the product of multiple dynamic equilibria, the breakdown of which contributes to age-dependent sensory decline. The molecular mechanisms of homeostatic maintenance, however, are still poorly understood. The ears of vertebrates and insects are characterised by exquisite sensitivities but also marked functional vulnerabilities. Being under the permanent load of both thermal and acoustic noise, auditory transducer channels are prime examples for the homeostatic challenge. We show that (i) NompC-dependent mechanotransducers in the ear of the fruit fly Drosophila melanogaster undergo a continual turnover with estimated half-lives of ≈ 3h; (ii) a de novo synthesis of NompC can restore transducer function in the adult ears of congenitally deafened flies; (iii) key components of the auditory transduction chain, including NompC, are under activity-dependent transcriptional control, likely forming a transducer-operated gain control system.