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A03 - In vivo analysis of active zone assembly

Principal Investigators

Prof. Dr. Stephan Sigrist, FU Berlin

Dr. Astrid Petzoldt, FU Berlin

Synapses exocytose synaptic vesicles (SVs) at specialized membrane sites called active zones (AZs) covered by protein scaffolds, which control SV exocytosis. Bruchpilot (BRP) is a major scaffold building block in Drosophila. Our recent work suggests that DSyd-1 orchestrates the assembly of the BRP-scaffold via trans-synaptic DNrx-DNlg1 signaling (Figure 1). Here we combine Drosophila genetics with in vivo imaging and super-resolution light and electron microscopy to address the role of DSyd-1 and DNrx/DNlg1 in BRP-scaffold assembly. Novel factors involved in DSyd-1- and DNrx/DNlg1-mediated BRP-scaffold assembly shall be identified and the dynamics underlying BRP-scaffold assembly and turnover will be investigated.

Figure1: Model highlighting the role of Spn in controlling Nrx-1 synaptogenic activity in conjunction with Syd-1. The intracellular interaction of Nrx-1 (binding postsynaptic Nlg1 (dark blue)) with Syd-1, via a PDZ binding motif, marks the entry of a nascent synapse into an irreversible assembly stage. To keep this process in balance, Spn takes away fractions of Nrx-1, also via PDZ binding motif, to be stalled by Syd-1. Thus, Spn mediates the higher mobility of Nrx-1, ensuring the already stalled Nrx-1/Syd-1 complex will maturate (incorporation of BRP presynaptically and maturation of PSDs postsynaptically). In the absence of Spn, Nrx-1 is less mobile and, therefore, more efficiently dragged by Syd-1, resulting in many, but not fully matured synapses.


References:

  • Götz TWB, Puchkov D, Lysiuk V, Lützkendorf J, Nikonenko AG, Quentin C, Lehmann M, Sigrist SJ, Petzoldt AG. Rab2 regulates presynaptic precursor vesicle biogenesis at the trans-Golgi. J Cell Biol. 220(5):e202006040 (2021)

  • Vukoja A, Rey U, Petzoldt AG, Ott C, Vollweiter D, Quentin C, Puchkov D, Reynolds E, Lehmann M, Hohensee S, Rosa S, Lipowsky R, Sigrist SJ, Haucke V. Presynaptic Biogenesis Requires Axonal Transport of Lysosome-Related Vesicles. Neuron. 19;99(6):1216-1232.e7 (2018)

  • Lardong JA, Driller JH, Depner H, Weise C, Petzoldt A, Wahl MC, Sigrist SJ, Loll B. Structures of Drosophila melanogaster Rab2 and Rab3 bound to GMPPNP. Acta Crystallogr F Struct Biol Commun. 71(Pt 1):34-40 (2015)

  • Walter AM, Haucke V, Sigrist SJ. Neurotransmission: spontaneous and evoked release filing for divorce. Curr Biol. 24(5):R192-4 (2014)

  • Podufall J, Tian R, Knoche E, Puchkov D, Walter AM, Rosa S, Quentin C, Vukoja A, Jung N, Lampe A, Wichmann C, Böhme M, Depner H, Zhang YQ, Schmoranzer J, Sigrist SJ, Haucke V. A presynaptic role for the cytomatrix protein GIT in synaptic vesicle recycling. Cell Rep. 7(5):1417-1425 (2014)

  • Petzoldt AG, Lee YH, Khorramshahi O, Reynolds E, Plested AJ, Herzel H, Sigrist SJ. Gating characteristics control glutamate receptor distribution and trafficking in vivo. Curr Biol. 24(17):2059-65 (2014)

  • Owald D, Khorramshahi O, Gupta VK, Banovic D, Depner H, Fouquet W, Wichmann C, Mertel S, Eimer S, Reynolds E, Holt M, Aberle H, Sigrist SJ. Cooperation of Syd-1 with Neurexin synchronizes pre- with postsynaptic assembly. Nat Neurosci. 15(9):1219-26 (2012)

  • Haucke V, Neher E, Sigrist SJ. Protein scaffolds in the coupling of synaptic exocytosis and endocytosis. Nat Rev Neurosci. 12(3):127-38 (2011)

  • Liu KS, Siebert M, Mertel S, Knoche E, Wegener S, Wichmann C, Matkovic T, Muhammad K, Depner H, Mettke C, Bückers J, Hell SW, Müller M, Davis GW, Schmitz D, Sigrist SJ. RIM-binding protein, a central part of the active zone, is essential for neurotransmitter release. Science. 334(6062):1565-9 (2011)

  • Owald D, Fouquet W, Schmidt M, Wichmann C, Mertel S, Depner H, Christiansen F, Zube C, Quentin C, Körner J, Urlaub H, Mechtler K, Sigrist SJ. A Syd-1 homologue regulates pre- and postsynaptic maturation in Drosophila. J Cell Biol. 188(4):565-79 (2010)

  • Banovic D, Khorramshahi O, Owald D, Wichmann C, Riedt T, Fouquet W, Tian R, Sigrist SJ, Aberle H. Drosophila neuroligin 1 promotes growth and postsynaptic differentiation at glutamatergic neuromuscular junctions. Neuron. 66(5):724-38 (2010)

  • Owald D, Sigrist SJ. Assembling the presynaptic active zone. Curr Opin Neurobiol. 19(3):311-8 (2009)

  • Kittel RJ, Wichmann C, Rasse TM, Fouquet W, Schmidt M, Schmid A, Wagh DA, Pawlu C, Kellner RR, Willig KI, Hell SW, Buchner E, Heckmann M, Sigrist SJ. Bruchpilot promotes active zone assembly, Ca2+ channel clustering, and vesicle release. Science. 312(5776):1051-4 (2006)