A presynaptic role of microtubule-associated protein 1/Futsch in Drosophila: regulation of active zone number and neurotransmitter release.
Structural microtubule-associated proteins (MAPs), like MAP1, not only control the stability of microtubules, but also interact with postsynaptic proteins in the nervous system. Their presynaptic role has barely been studied. To tackle this question, we used the Drosophila model in which there is only one MAP1 homolog: Futsch, which is expressed at the larval neuromuscular junction, presynaptically only. We show that Futsch regulates neurotransmitter release and active zone density. Importantly, we provide evidence that this role of Futsch is not just the consequence of its microtubule-stabilizing function. Using high-resolution microscopy, we show that Futsch and microtubules are almost systematically present in close proximity to active zones, with Futsch being localized in-between microtubules and active zones. Using proximity ligation assays, we further demonstrate the proximity of Futsch, but not microtubules, to active zone components. Altogether our data are in favor of a model by which Futsch locally stabilizes active zones, by reinforcing their link with the underlying microtubule cytoskeleton.
Institut de Génomique Fonctionnelle, CNRS-UMR5203, INSERM-U661, Université Montpellier, Montpellier, Cedex 5, F-34094, France.
Simon
S
Lepicard
Institut de Génomique Fonctionnelle, CNRS-UMR5203, INSERM-U661, Université Montpellier, Montpellier, Cedex 5, F-34094, France.
Bénédicte
B
Franco
Institut de Génomique Fonctionnelle, CNRS-UMR5203, INSERM-U661, Université Montpellier, Montpellier, Cedex 5, F-34094, France.
Frédéric
F
de Bock
Institut de Génomique Fonctionnelle, CNRS-UMR5203, INSERM-U661, Université Montpellier, Montpellier, Cedex 5, F-34094, France Marie-Laure.Parmentier@igf.cnrs.fr.
Marie-Laure
ML
Parmentier
D000818:Animals; D030801:Animals, Genetically Modified; D001370:Axonal Transport / Q000235:genetics; D003599:Cytoskeleton / Q000235:genetics / Q000378:metabolism; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000235:genetics / Q000378:metabolism*; D009469:Neuromuscular Junction / Q000235:genetics / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology*
D029721:Drosophila Proteins; D008869:Microtubule-Associated Proteins; C409635:futsch protein, Drosophila; D018698:Glutamic Acid
active zone; microtubule-associated protein; microtubules; neuromuscular junction; synaptic release