Fig. 1: A large-scale screening identified proteasome inhibitors as CREB activators.
a Schematics of a compound screening in adult flies. Compounds were mixed in gum Arabic (GA) micelles and delivered to flies by U-GLAD (U-shaped GA liquid-assisted delivery) system. In brief, compound powder was grinded with gum Arabic and dissolved in chemical defined liquid food at 5 mg/ml. Drug containing liquid food was delivered to the flies through a U-shaped glass capillary by siphoning. Details refer to the main text and the method section. b Summary of compound screening results. A compound library contains 1853 FDA approved drug library and 215 natural products was screened. Classification of the positive hits (those with more than 5-fold increase of CRE-LUC) in the library were presented. c Proteasome inhibitors promote CREB activity in adult flies. Compounds were fed at 5 mg/ml for 24 h. One-way ANOVA analysis for statistics, ***P < 0.001. CRE-LUC activity was normalized with total protein content. d CREB expression was examined in fly intestine by anti-CREB staining. DAPI counterstains nuclei in blue. Arrowheads denotes typical CREB signals in ECs. Scale bar: 10 μm. e Intestinal CRE-LUC activity was examined when proteasome subunit prosβ5 was inhibited in enterocytes at 29 °C for 4 days. Student’s t-test performed for statistics. *P < 0.05. n = 15 for each condition. Genotype: NP1-Gal4ts, UAS-prosβ5RNAi. f Intestinal CRE-LUC activity induced by MLN2238 or β5RNAi is suppressed by CREBDN. Student’s t-test performed for statistics. *P < 0.05, **P < 0.01, n = 15 for each condition. Genotypes: NP1-Gal4ts; UAS-prosβ5RNAi and NP1-Gal4ts; UAS-CREBDN, UAS-prosβ5RNAi.
