Abstract
Members of the semaphorin family of secreted and transmembrane proteins utilize plexins as neuronal receptors to signal repulsive axon guidance. It remains unknown how plexin proteins are directly linked to the regulation of cytoskeletal dynamics. Here, we show that Drosophila MICAL, a large, multidomain, cytosolic protein expressed in axons, interacts with the neuronal plexin A (PlexA) receptor and is required for Semaphorin 1a (Sema-1a)-PlexA-mediated repulsive axon guidance. In addition to containing several domains known to interact with cytoskeletal components, MICAL has a flavoprotein monooxygenase domain, the integrity of which is required for Sema-1a-PlexA repulsive axon guidance. Vertebrate orthologs of Drosophila MICAL are neuronally expressed and also interact with vertebrate plexins, and monooxygenase inhibitors abrogate semaphorin-mediated axonal repulsion. These results suggest a novel role for oxidoreductases in repulsive neuronal guidance.
MeSH terms
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Actins / metabolism
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Adaptor Proteins, Signal Transducing
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Amino Acid Sequence
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Animals
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Axons / enzymology
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Axons / metabolism*
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Binding Sites
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Blotting, Western
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Cell Adhesion Molecules / genetics
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Cell Adhesion Molecules / metabolism*
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Cell Adhesion Molecules, Neuronal / genetics
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Cell Adhesion Molecules, Neuronal / metabolism
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Conserved Sequence
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Cytoskeletal Proteins / antagonists & inhibitors
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Cytoskeletal Proteins / chemistry
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Cytoskeletal Proteins / genetics
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Cytoskeletal Proteins / metabolism*
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Cytoskeleton / metabolism
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Drosophila Proteins / genetics
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Drosophila Proteins / metabolism
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Drosophila melanogaster / enzymology*
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Drosophila melanogaster / genetics
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Flavin-Adenine Dinucleotide / metabolism
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Flavoproteins / antagonists & inhibitors
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Flavoproteins / chemistry
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Flavoproteins / genetics
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Flavoproteins / metabolism*
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Humans
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Intracellular Signaling Peptides and Proteins
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LIM Domain Proteins
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Microfilament Proteins
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Mixed Function Oxygenases
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Molecular Sequence Data
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Mutation
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Nerve Tissue Proteins / genetics
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Nerve Tissue Proteins / metabolism*
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Oxidoreductases / antagonists & inhibitors
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Oxidoreductases / chemistry
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Oxidoreductases / genetics
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Oxidoreductases / metabolism*
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Phenotype
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Protein Binding
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Protein Structure, Tertiary
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Semaphorins*
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Sequence Homology, Amino Acid
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Signal Transduction
Substances
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Actins
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Adaptor Proteins, Signal Transducing
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Cell Adhesion Molecules
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Cell Adhesion Molecules, Neuronal
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Cytoskeletal Proteins
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Drosophila Proteins
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Flavoproteins
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Intracellular Signaling Peptides and Proteins
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LIM Domain Proteins
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Microfilament Proteins
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Nerve Tissue Proteins
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Semaphorins
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plexin
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Flavin-Adenine Dinucleotide
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MICAL1 protein, human
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Mixed Function Oxygenases
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Oxidoreductases