Abstract
The primary cilium is required for Hedgehog signaling. So far, all known ciliogenic proteins regulate Hedgehog signaling through their role in ciliogenesis. Here we show that the mouse DZIP1 regulates Hedgehog signaling through two mechanisms. First, DZIP1 interacts with GLI3, a transcriptional regulator for Hedgehog signaling, and prevents GLI3 from entering the nucleus. Second, DZIP1 is required for ciliogenesis. We show that DZIP1 colocalizes and interacts with CEP164, a protein localizing at appendages of the mother centrioles, and IFT88, a component of the intraflagellar transport (IFT) machinery. Functionally, both CEP164 and Ninein appendage proteins fail to localize to ciliary appendages in Dzip1 mutant cells; IFT components are not recruited to the basal body of cilia. Importantly, the accumulation of GLI3 in the nucleus is independent of loss of primary cilia in Dzip1 mutant cells. Therefore, DZIP1 is the first known ciliogenic protein that regulates Hedgehog signaling through a dual mechanism and that biochemically links IFT machinery with Hedgehog pathway components.
Keywords:
Cilia; Hedgehog; Protein-Protein Interactions; Signaling; Transcription Factors.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Adaptor Proteins, Signal Transducing
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Animals
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Cell Line
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Cells, Cultured
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Centrioles / metabolism
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Centrosome / metabolism
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Cilia / genetics
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Cilia / metabolism
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Cilia / physiology*
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Cytoplasm / metabolism
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Cytoskeletal Proteins / genetics
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Cytoskeletal Proteins / metabolism
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Embryo, Mammalian / cytology
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Embryo, Mammalian / embryology
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Embryo, Mammalian / metabolism
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Fibroblasts / cytology
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Fibroblasts / metabolism
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HEK293 Cells
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Hedgehog Proteins / genetics
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Hedgehog Proteins / metabolism*
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Humans
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Immunoblotting
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Kruppel-Like Transcription Factors / genetics
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Kruppel-Like Transcription Factors / metabolism*
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Mice
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Microscopy, Fluorescence
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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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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism
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Protein Binding
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RNA Interference
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Signal Transduction / genetics
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Signal Transduction / physiology*
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Tumor Suppressor Proteins / genetics
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Tumor Suppressor Proteins / metabolism
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Zinc Finger Protein Gli3
Substances
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Adaptor Proteins, Signal Transducing
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Cytoskeletal Proteins
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DNA-Binding Proteins
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Dzip1 protein, mouse
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Gli3 protein, mouse
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Hedgehog Proteins
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Kruppel-Like Transcription Factors
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Nerve Tissue Proteins
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Nin protein, mouse
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Nuclear Proteins
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Tg737Rpw protein, mouse
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Tumor Suppressor Proteins
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Zinc Finger Protein Gli3