Molecular basis of synaptic specificity by immunoglobulin superfamily receptors in Drosophila
Shouqiang Cheng,
James Ashley,
Justyna D Kurleto,
Meike Lobb-Rabe,
Yeonhee Jenny Park,
Robert A Carrillo,
Engin Özkan
Affiliations
Shouqiang Cheng
Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, United States
James Ashley
Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, United States
Justyna D Kurleto
Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, United States; Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
Meike Lobb-Rabe
Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, United States; Graduate Program in Cell and Molecular Biology, University of Chicago, Chicago, United States
Yeonhee Jenny Park
Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, United States
In stereotyped neuronal networks, synaptic connectivity is dictated by cell surface proteins, which assign unique identities to neurons, and physically mediate axon guidance and synapse targeting. We recently identified two groups of immunoglobulin superfamily proteins in Drosophila, Dprs and DIPs, as strong candidates for synapse targeting functions. Here, we uncover the molecular basis of specificity in Dpr–DIP mediated cellular adhesions and neuronal connectivity. First, we present five crystal structures of Dpr–DIP and DIP–DIP complexes, highlighting the evolutionary and structural origins of diversification in Dpr and DIP proteins and their interactions. We further show that structures can be used to rationally engineer receptors with novel specificities or modified affinities, which can be used to study specific circuits that require Dpr–DIP interactions to help establish connectivity. We investigate one pair, engineered Dpr10 and DIP-α, for function in the neuromuscular circuit in flies, and reveal roles for homophilic and heterophilic binding in wiring.