RESEARCH ARTICLE A kinase-dependent feedforward loop affects CREBB stability and long term memory formation Pei-Tseng Lee1, Guang Lin1, Wen-Wen Lin1, Fengqiu Diao2, Benjamin H White2, Hugo J Bellen1,3,4,5,6* 1Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States; 2Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, United States; 3Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States; 4Program in Developmental Biology, Baylor College of Medicine, Houston, United States; 5Department of Neuroscience, Baylor College of Medicine, Houston, United States; 6Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, United States Abstract In Drosophila, long-term memory (LTM) requires the cAMP-dependent transcription factor CREBB, expressed in the mushroom bodies (MB) and phosphorylated by PKA. To identify other kinases required for memory formation, we integrated Trojan exons encoding T2A-GAL4 into genes encoding putative kinases and selected for genes expressed in MB. These lines were screened for learning/memory deficits using UAS-RNAi knockdown based on an olfactory aversive conditioning assay. We identified a novel, conserved kinase, Meng-Po (MP, CG11221, SBK1 in human), the loss of which severely affects 3 hr memory and 24 hr LTM, but not learning. Remarkably, memory is lost upon removal of the MP protein in adult MB but restored upon its *For correspondence: reintroduction. Overexpression of MP in MB significantly increases LTM in wild-type flies showing
[email protected] that MP is a limiting factor for LTM. We show that PKA phosphorylates MP and that both proteins synergize in a feedforward loop to control CREBB levels and LTM.