Fig. 6. dRTN4IP1, a Drosophila ortholog of RTN4IP1, is required for CoQ biogenesis and mitochondrial function in Drosophila.
a, Scheme of experiments using Act-GAL4 (whole body) and Mef2-GAL4 (muscle) drivers in dRTN4IP1-knockdown (KD) flies and their phenotypes. b, Histograms of LC–PRM assay results and representative LC–PRM chromatograms of endogenous CoQ9, CoQ9H2, CoQ10 and CoQ10H2, which were all detected as a form of ammonium adduct (NH4+), in control and whole-body Dmel/CG17221-KD fruit fly larvae (n = 4 biological replicates). c, TEM images of the mitochondrial morphology of indirect flight muscle in muscle-specific dRTN4IP1-KD flies. Scale bars, 5 µm (upper) and 1 µm (lower). d, Climbing assay for muscle-specific dRTN4IP1-KD (left), control (middle) and CoQ2-treated flies of muscle-specific dRTN4IP-KD (right). In the negative geotaxis assay, flies climbing over 8 cm were counted over 10 s. For CoQ2 treatment, CoQ2-containing foods (50 μg g−1) were treated to 3–5-day male flies for 24 h (n = 6 biological replicates). e, Proposed model of the RTN4IP1–CoQ axis and its function in the mitochondria. Mean values are shown with error bars representing the standard deviation. Statistical significance was determined using a two-tailed Student’s t-test: *P < 0.05, **P < 0.01, ***P < 0.001. Source data can be found in the Source Data file.