Christine Quentin

Publications (2)25.8 Total impact

• Source

  Available from: Sara Mertel

  Article: A Syd-1 homologue regulates pre- and postsynaptic maturation in Drosophila.

  David Owald, Wernher Fouquet, Manuela Schmidt, Carolin Wichmann, Sara Mertel, Harald Depner, Frauke Christiansen, Christina Zube, Christine Quentin, Jorg Körner, Henning Urlaub, Karl Mechtler, Stephan J Sigrist
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  ABSTRACT: Active zones (AZs) are presynaptic membrane domains mediating synaptic vesicle fusion opposite postsynaptic densities (PSDs). At the Drosophila neuromuscular junction, the ELKS family member Bruchpilot (BRP) is essential for dense body formation and functional maturation of AZs. Using a proteomics approach, we identified Drosophila Syd-1 (DSyd-1) as a BRP binding partner. In vivo imaging shows that DSyd-1 arrives early at nascent AZs together with DLiprin-alpha, and both proteins localize to the AZ edge as the AZ matures. Mutants in dsyd-1 form smaller terminals with fewer release sites, and release less neurotransmitter. The remaining AZs are often large and misshapen, and ectopic, electron-dense accumulations of BRP form in boutons and axons. Furthermore, glutamate receptor content at PSDs increases because of excessive DGluRIIA accumulation. The AZ protein DSyd-1 is needed to properly localize DLiprin-alpha at AZs, and seems to control effective nucleation of newly forming AZs together with DLiprin-alpha. DSyd-1 also organizes trans-synaptic signaling to control maturation of PSD composition independently of DLiprin-alpha.
  The Journal of Cell Biology 02/2010; 188(4):565-79. · 10.26 Impact Factor
• Source

  Available from: Manfred Heckmann

  Article: Glutamate receptor dynamics organizing synapse formation in vivo.

  Tobias M Rasse, Wernher Fouquet, Andreas Schmid, Robert J Kittel, Sara Mertel, Carola B Sigrist, Manuela Schmidt, Asja Guzman, Carlos Merino, Gang Qin, Christine Quentin, Frank F Madeo, Manfred Heckmann, Stephan J Sigrist
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  ABSTRACT: Insight into how glutamatergic synapses form in vivo is important for understanding developmental and experience-triggered changes of excitatory circuits. Here, we imaged postsynaptic densities (PSDs) expressing a functional, GFP-tagged glutamate receptor subunit (GluR-IIA(GFP)) at neuromuscular junctions of Drosophila melanogaster larvae for several days in vivo. New PSDs, associated with functional and structural presynaptic markers, formed independently of existing synapses and grew continuously until reaching a stable size within hours. Both in vivo photoactivation and photobleaching experiments showed that extrasynaptic receptors derived from diffuse, cell-wide pools preferentially entered growing PSDs. After entering PSDs, receptors were largely immobilized. In comparison, other postsynaptic proteins tested (PSD-95, NCAM and PAK homologs) exchanged faster and with no apparent preference for growing synapses. We show here that new glutamatergic synapses form de novo and not by partitioning processes from existing synapses, suggesting that the site-specific entry of particular glutamate receptor complexes directly controls the assembly of individual PSDs.
  Nature Neuroscience 08/2005; 8(7):898-905. · 15.53 Impact Factor