Figure 1.

ATP concentration decreases in the cell body but not in the axon during aging

(A) A reduction in ATP concentration, caused by the inhibition of mitochondrial respiration by antimycin in adult fly brain neurons, was identified using ATeam. ATeam expression was driven by the pan-neuronal driver elav-GAL4. Quantification of the FRET signal (right panels) is shown (mean ± standard error [SE], n = 7–8; ∗p < 0.05, ∗∗∗p < 0.001; Student's t-test).

(B) Schematic representation of mitochondrial transport. The knockdown of milton, an adapter protein for mitochondrial transport, depleted mitochondria in the axon.

(C) Neuronal knockdown of milton reduced ATP concentration in Kenyon cells and lobe tips. Flies carrying the driver with control RNAi (elav/ATeam, control RNAi) were used as controls. Data are mean ± SE, n = 48–65; not significant (n.s.), p > 0.05, ∗∗∗p < 0.001; Student's t-test).

(D) The FRET efficiency of ATeam in Kenyon cells (A) and lobe tips (B) of the mushroom body of 5-, 30-, and 50-day-old flies (n = 12–49; n.s., p > 0.05, ∗∗∗p < 0.001; one-way analysis of variance (ANOVA), followed by Tukey's HSD multiple comparisons test). ATeam expression was driven in neurons by the pan-neuronal driver Elav-GAL4.