Np65-mediated synaptic ratio 1 Structure of excitatory synapses and GABA A receptor localization at inhibitory synapses are regulated by Neuroplastin-65 Rodrigo Herrera-Molina 1,2,7 , Isabella Sarto-Jackson 5 , Carolina Montenegro-Venegas 1 , Martin Heine 3 , Karl-Heinz Smalla 2,8 , Constanze I. Seidenbecher 1,8 , Philip W. Beesley 6 , Eckart D. Gundelfinger 1,8,9 , and Dirk Montag 4 From the 1 Department of Neurochemistry and Molecular Biology, the 2 Special Laboratory for Molecular Biology Techniques, the 3 Research Group Molecular Physiology, and the 4 Neurogenetics Special Laboratory of the Leibniz Institute for Neurobiology, 8 the Center of Behavioral Brain Sciences (CBBS), and 9 Faculty of Medicine, Otto von Guericke University, Magdeburg, Germany 5 the Center for Brain Research, Department of Biochemistry and Molecular Biology of the Nervous System, Medical University of Vienna, Vienna, Austria 6 the School of Biological Sciences, Royal Holloway University of London, Egham, UK 7 Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Chile *Running title: Np65-mediated synaptic ratio To whom correspondence should be addressed: PD Dr. Dirk Montag, Neurogenetics Special Laboratory, Leibniz Institute for Neurobiology, Brenneckestrasse 6, 39118 Magdeburg, Germany. Tel.: (+49) 391-6263-94241; Fax: (+49) 391-6263-94249; e-mail: montag@LIN-magdeburg.de Keywords: Synapses, GABA A receptors, Neurons, Cell adhesion, Synaptic plasticity, Neuroplastin, Synapse formation and maintenance, Cell adhesion molecule CAM, Ig-superfamily