Figure 7. Changing periodicity of inhibition pulses reveals JNK pathway resonance.

(a,b) Cerebellar granule neuron cultures were transfected with NES-OptoJNKi and the c-Jun reporter system as Fig. 6c. Wells were illuminated (1.5 s pulses at 600 μJ cm⁻² s⁻¹ as before) with periodicity as indicated. (a) The maximal inhibition of the ΔMEKK1-evoked GAL4-cJun response was achieved at 7.5 and 180 s periodicities. Less inhibition occurred between 7.5 and 180 s and inhibition falls once again after 180 s. (b) Percentage inhibition compared with ΔMEKK1/no OptoJNKi/darkness was calculated from the experiments presented in Fig. 7a. Significance of differences from 7.5 s periodicity in the presence of NES-OptoJNKi are highlighted (n=8). (c,d) Cerebellar granule neuron cultures were transfected and illuminated as in Fig. 7a,b but with NLS-OptoJNKi in place of NES-OptoJNKi. (c) Inhibition of the ΔMEKK1-evoked GAL4-cJun response was observed at 7.5–30 s periodicity but inhibition was stronger with 60 s periodicity, and fell at longer periodicities. (d) Percentage inhibition compared with ΔMEKK1/no OptoJNKi/darkness was calculated from the experiments presented in Fig. 7c. Significance of differences from 7.5 s periodicity in the presence of NLS-OptoJNKi are highlighted (n=8). Mean±s.e.m. is indicated, ns indicates not significant, *P<0.05, **P<0.01, ***P<0.001. Statistical analysis was carried out by two-way ANOVA/Neuman–Keuls post-test (Supplementary Data 1).