Control of Synaptic Specificity by Establishing a Relative Preference for Synaptic Partners

• DOI: 10.1016/j.neuron.2019.06.006
• Publication Date: 2019-07-09T14:37:52Z
• Authors: Chundi Xu; Emma Theisen; Ryan Maloney; Jing Peng; Ivan Santiago; Clarence Yapp; Zachary Werkhoven; Elijah Rumbaut; Bryan Shum; Dorota Tarnogorska; Jolanta Borycz; Liming Tan; Maximilien Courgeon; Tessa Griffin; Raina Levin; Ian A. Meinertzhagen; Benjamin de Bivort; Jan Drugowitsch; Matthew Y. Pecot
• Keywords: Animals, Genetically Modified; Neurons; 0301 basic medicine; 03 medical and health sciences; Drosophila melanogaster; Optic Lobe, Nonmammalian; Synapses; Animals; Drosophila Proteins; Immunoglobulins; Membrane Proteins; Protein Interaction Maps

The ability of neurons to identify correct synaptic partners is fundamental to the proper assembly and function of neural circuits. Relative to other steps in circuit formation such as axon guidance, our knowledge of how synaptic partner selection is regulated is severely limited. Drosophila Dpr and DIP immunoglobulin superfamily (IgSF) cell-surface proteins bind heterophilically and are expressed in a complementary manner between synaptic partners in the visual system. Here, we show that in the lamina, DIP mis-expression is sufficient to promote synapse formation with Dpr-expressing neurons and that disrupting DIP function results in ectopic synapse formation. These findings indicate that DIP proteins promote synapses to form between specific cell types and that in their absence, neurons synapse with alternative partners. We propose that neurons have the capacity to synapse with a broad range of cell types and that synaptic specificity is achieved by establishing a preference for specific partners.