title: Rapid activity-dependent modifications in synaptic structure and function require bidirectional Wnt signaling.
abstract: Activity-dependent modifications in synapse structure play a key role in synaptic development and plasticity, but the signaling mechanisms involved are poorly understood. We demonstrate that glutamatergic Drosophila neuromuscular junctions undergo rapid changes in synaptic structure and function in response to patterned stimulation. These changes, which depend on transcription and translation, include formation of motile presynaptic filopodia, elaboration of undifferentiated varicosities, and potentiation of spontaneous release frequency. Experiments indicate that a bidirectional Wnt/Wg signaling pathway underlies these changes. Evoked activity induces Wnt1/Wg release from synaptic boutons, which stimulates both a postsynaptic DFz2 nuclear import pathway as well as a presynaptic pathway involving GSK-3beta/Shaggy. Our findings suggest that bidirectional Wg signaling operates downstream of synaptic activity to induce modifications in synaptic structure and function. We propose that activation of the postsynaptic Wg pathway is required for the assembly of the postsynaptic apparatus, while activation of the presynaptic Wg pathway regulates cytoskeletal dynamics.
authors.affiliation: Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors.forename: Bulent
authors.initials: B
authors.lastname: Ataman
authors.forename: James
authors.initials: J
authors.lastname: Ashley
authors.forename: Michael
authors.initials: M
authors.lastname: Gorczyca
authors.forename: Preethi
authors.initials: P
authors.lastname: Ramachandran
authors.forename: Wernher
authors.initials: W
authors.lastname: Fouquet
authors.forename: Stephan J
authors.initials: SJ
authors.lastname: Sigrist
authors.forename: Vivian
authors.initials: V
authors.lastname: Budnik
mesh_terms: D000818:Animals; D004330:Drosophila; D029721:Drosophila Proteins / Q000737:chemistry / Q000502:physiology*; D009469:Neuromuscular Junction / Q000737:chemistry / Q000502:physiology; D017729:Presynaptic Terminals / Q000737:chemistry / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D013569:Synapses / Q000737:chemistry / Q000502:physiology*; D051153:Wnt Proteins / Q000737:chemistry / Q000502:physiology*
chemical_list: D029721:Drosophila Proteins; D051153:Wnt Proteins