Activity-dependent synaptic capture of transiting peptidergic vesicles.
Synapses require resources synthesized in the neuronal soma, but there are no known mechanisms to overcome delays associated with the synthesis and axonal transport of new proteins generated in response to activity, or to direct resources specifically to active synapses. Here, in vivo imaging of the Drosophila melanogaster neuromuscular junction reveals a cell-biological strategy that addresses these constraints. Peptidergic vesicles continually transit through resting terminals, but retrograde peptidergic vesicle flux is accessed following activity to rapidly boost neuropeptide content in synaptic boutons. The presence of excess transiting vesicles implies that synaptic neuropeptide stores are limited by the capture of peptidergic vesicles at the terminal, rather than by synthesis in the soma or delivery via the axon. Furthermore, activity-dependent capture from a pool of transiting vesicles provides a nerve terminal-based mechanism for directing distally and slowly generated resources quickly to active synapses. Finally, retrograde transport in the nerve terminal is regulated by activity.
Shakiryanova
Dinara
D
Department of Pharmacology, University of Pittburgh, Pittsburgh, Pennsylvania 15261, USA.
Tully
Arvonn
A
Levitan
Edwin S
ES
D000818:Animals; D001370:Axonal Transport / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D004331:Drosophila melanogaster; D004558:Electric Stimulation / Q000379:methods; D007700:Kinetics; D007814:Larva; D008855:Microscopy, Electron, Scanning / Q000379:methods; D009469:Neuromuscular Junction / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects / Q000648:ultrastructure; D009479:Neuropeptides / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D022142:Secretory Vesicles / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D013572:Synaptic Vesicles / Q000378:metabolism* / Q000648:ultrastructure; D013997:Time Factors
D009479:Neuropeptides; D011189:Potassium Chloride