PT - JOURNAL ARTICLE AU - Albert I. Chen AU - Cindy N. Nguyen AU - David R. Copenhagen AU - Sylvia Badurek AU - Liliana Minichiello AU - Barbara Ranscht AU - Louis F. Reichardt TI - TrkB (Tropomyosin-Related Kinase B) Controls the Assembly and Maintenance of GABAergic Synapses in the Cerebellar Cortex AID - 10.1523/JNEUROSCI.4991-10.2011 DP - 2011 Feb 23 TA - The Journal of Neuroscience PG - 2769--2780 VI - 31 IP - 8 4099 - http://www.jneurosci.org/content/31/8/2769.short 4100 - http://www.jneurosci.org/content/31/8/2769.full SO - J. Neurosci.2011 Feb 23; 31 AB - Inhibitory interneurons play a critical role in coordinating the activity of neural circuits. To explore the mechanisms that direct the organization of inhibitory circuits, we analyzed the involvement of tropomyosin-related kinase B (TrkB) in the assembly and maintenance of GABAergic inhibitory synapses between Golgi and granule cells in the mouse cerebellar cortex. We show that TrkB acts directly within each cell-type to regulate synaptic differentiation. TrkB is required not only for assembly, but also maintenance of these synapses and acts, primarily, by regulating the localization of synaptic constituents. Postsynaptically, TrkB controls the localization of a scaffolding protein, gephyrin, but acts at a step subsequent to the localization of a cell adhesion molecule, Neuroligin-2. Importantly, TrkB is required for the localization of an Ig superfamily cell adhesion molecule, Contactin-1, in Golgi and granule cells and the absence of Contactin-1 also results in deficits in inhibitory synaptic development. Thus, our findings demonstrate that TrkB controls the assembly and maintenance of GABAergic synapses and suggest that TrkB functions, in part, through promoting synaptic adhesion.