<em>Drosophila Fatty Acid Transport Protein</em> Regulates Rhodopsin-1 Metabolism and Is Required for Photoreceptor Neuron Survival

<div><p>Tight regulation of the visual response is essential for photoreceptor function and survival. Visual response dysregulation often leads to photoreceptor cell degeneration, but the causes of such cell death are not well understood. In this study, we investigated a <em>fatty acid transport protein</em> (<em>fatp</em>) null mutation that caused adult-onset and progressive photoreceptor cell death. Consistent with <em>fatp</em> having a role in the retina, we showed that <em>fatp</em> is expressed in adult photoreceptors and accessory cells and that its re-expression in photoreceptors rescued photoreceptor viability in <em>fatp</em> mutants. The visual response in young <em>fatp</em>-mutant flies was abnormal with elevated electroretinogram amplitudes associated with high levels of Rhodopsin-1 (Rh1). Reducing Rh1 levels in <em>rh1</em> mutants or depriving flies of vitamin A rescued photoreceptor cell death in <em>fatp</em> mutant flies. Our results indicate that <em>fatp</em> promotes photoreceptor survival by regulating Rh1 abundance.</p>