Other transgenic strains were generated using standard techniques as detailed in the Supplemental

Experimental Procedures. Other methods are detailed in the Supplemental Experimental Procedures. This work was supported by the Howard Hughes Medical Institute, the National Institutes of Health NIH 5R01 NS048392, the National Major Basic Research Program of China (2011CB910503), and the National Natural Science Foundation of China (31070657 and 31190062). We thank the Caenorhabditis Genetics Center, the National Bioresource Project (Japan), G. Maro, P. Kurshan, and the laboratories of J. Bessereau, K. Kontani, S. Mitani, Y. Jin, M. Nachury, and S. Munro for strains and reagents. We also thank S. Shaham for help with the analysis of the whole-genome sequencing data, C. Gao and Y. Fu for technical assistance, and A. McAllister, M. Klassen, and P. Kushan for thoughtful comments on the manuscript. Y.E.W. and K.S. designed buy AC220 experiments and wrote the paper. C.I.M. built some transgenes for dynamic imaging. L.H. and W.F. performed the experiments in Figure 8. Y.E.W.

performed the other experiments and analyzed the data. “
“The differentiation of synaptic terminals encompasses a profound re-organization of the axonal cytoskeleton and presynaptic membrane organelles. Hallmarks of this morphogenetic process are the assembly of active zones, accumulation of synaptic vesicles in the terminal, and the docking learn more of a pool of vesicles medroxyprogesterone at the release sites. At mature synapses, a complex cytoplasmic network consisting of scaffolding and cytomatrix proteins orchestrates morphological and functional properties of release sites (Zhai and Bellen, 2004, Ziv and Garner, 2004, Arikkath and Reichardt, 2008, Shen and Scheiffele, 2010, Gundelfinger and Fejtova, 2012 and Südhof, 2012). The large ELKS, piccolo, and bassoon proteins represent major structural building blocks of the cytomatrix. Moreover, munc18, munc13, RIM,

and CAPS proteins are essential for the maintenance of a docked pool of synaptic vesicles (Weimer et al., 2003, Jockusch et al., 2007, Verhage and Sørensen, 2008, Siksou et al., 2009 and Han et al., 2011). Several trans-synaptic signaling systems have been implicated in instructing the presynaptic differentiation process, but the cytoplasmic mechanisms that relay such signals are only beginning to emerge ( Biederer and Stagi, 2008 and Johnson et al., 2009). In mammals, a Fer/Beta-catenin/beta-PIX signaling cascade modulates the overall abundance of synaptic vesicles in presynaptic terminals through organization of the actin cytoskeleton ( Sun and Bamji, 2011). However, molecular mechanisms that link cell surface receptors to cytoplasmic regulators of active zone morphogenesis, synaptic vesicle accumulation, and docking remain to be identified.