BLOCKING ENDOCYTOSIS IN DROSOPHILA'S CIRCADIAN PACEMAKER NEURONS INTERFERES WITH THE ENDOGENOUS CLOCK IN A PDF-DEPENDENT WAY

The neuropeptide pigment-dispersing factor (PDF) plays an essential role in the circadian clock of the fruit fly Drosophila melanogaster, but many details of PDF signaling in the clock network are still unknown. We tried to interfere with PDF signaling by blocking the GTPase Shibire in PDF neurons....

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Bibliographic Details
Published in:Chronobiology international 2009-10, Vol.26 (7), p.1307-1322
Main Authors: Wülbeck, Corinna, Grieshaber, Eva, Helfrich-Förster, Charlotte
Format: Article
Language:English
Subjects:
Animals
Animals, Genetically Modified
Brain - physiology
Circadian Rhythm - physiology
Drosophila
Drosophila melanogaster - genetics
Drosophila melanogaster - physiology
Drosophila Proteins - antagonists & inhibitors
Drosophila Proteins - genetics
Drosophila Proteins - physiology
Dynamin
Dynamins - antagonists & inhibitors
Dynamins - genetics
Dynamins - physiology
Endocytosis - physiology
Female
Genes, Insect
Male
Motor Activity
Mutation
Neurons - physiology
Neuropeptide signaling
Neuropeptides - physiology
Photoperiod
Pigment-dispersing factor
Receptors, G-Protein-Coupled - genetics
Receptors, G-Protein-Coupled - physiology
Shibire
Signal Transduction
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Summary:The neuropeptide pigment-dispersing factor (PDF) plays an essential role in the circadian clock of the fruit fly Drosophila melanogaster, but many details of PDF signaling in the clock network are still unknown. We tried to interfere with PDF signaling by blocking the GTPase Shibire in PDF neurons. Shibire is an ortholog of the mammalian Dynamins and is essential for endocytosis of clathrin-coated vesicles at the plasma membrane. Such endocytosis is used for neurotransmitter reuptake by presynaptic neurons, which is a prerequisite of synaptic vesicle recycling, and receptor-mediated endocytosis in the postsynaptic neuron, which leads to signal termination. By blocking Shibire function via overexpression of a dominant negative mutant form of Shibire in PDF neurons, we slowed down the behavioral rhythm by 3 h. This effect was absent in PDF receptor null mutants, indicating that we interfered with PDF receptor-mediated endocytosis. Because we obtained similar behavioral phenotypes by increasing the PDF level in regions close to PDF neurons, we conclude that blocking Shibire did prolong PDF signaling in the neurons that respond to PDF. Obviously, terminating the PDF signaling via receptor-mediated endocytosis is a crucial step in determining the period of behavioral rhythms. (Author correspondence: charlotte.foerster@biologie.uni-regensburg.de)
ISSN:0742-0528
1525-6073
DOI:10.3109/07420520903433315