Abstract
Neurexins are neuron-specific cell surface molecules thought to localize to presynaptic membranes. Recent genetic studies using Drosophila melanogaster have implicated an essential role for a single Drosophila neurexin (dnrx) in the proper architecture, development and function of synapses in vivo. However, the precise mechanisms underlying these actions are not fully understood. To elucidate the molecular mechanism of Neurexin in vivo, we employed dnrx and caki mutant flies, combined with various methods, and analyzed the animals' locomotion, synaptic vesicle cycling and neurotransmission of neuromuscular junctions. We found that Dneurexin (DNRX) is important for locomotion through a genetic interaction with the scaffold protein, CAKI/CMG, the Drosophila homolog of vertebrate CASK. Similar to its mammalian counterparts, DNRX is essential for synaptic vesicle cycling, which plays critical roles in neurotransmission at neuromuscular junctions (NMJ). However, this interaction appears not to be required for the synaptic targeting of DNRX, but may instead be needed for proper synaptic function, possibly by regulating the synaptic vesicle cycling process.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Animals, Genetically Modified
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Calcium-Calmodulin-Dependent Protein Kinases / genetics*
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Calcium-Calmodulin-Dependent Protein Kinases / metabolism
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Cell Adhesion Molecules, Neuronal / genetics*
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Cell Adhesion Molecules, Neuronal / metabolism
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Cell Differentiation / genetics
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Drosophila Proteins / genetics*
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Drosophila Proteins / metabolism
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Drosophila melanogaster / cytology
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Drosophila melanogaster / genetics*
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Drosophila melanogaster / metabolism
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Endocytosis / genetics
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Gene Expression Regulation, Developmental / genetics*
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Larva / genetics
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Larva / growth & development
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Larva / metabolism
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Motor Activity / genetics
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Mutation / genetics
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Neuromuscular Junction / genetics*
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Neuromuscular Junction / growth & development
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Neuromuscular Junction / metabolism
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Protein Structure, Tertiary / genetics
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Protein Transport / genetics
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Synapses / genetics
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Synapses / metabolism
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Synapses / ultrastructure
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Synaptic Transmission / genetics*
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Synaptic Vesicles / genetics
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Synaptic Vesicles / metabolism
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Synaptic Vesicles / ultrastructure
Substances
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Cell Adhesion Molecules, Neuronal
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Drosophila Proteins
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Nrx protein, Drosophila
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CASK protein, Drosophila
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Calcium-Calmodulin-Dependent Protein Kinases