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Arl13b regulates Shh signaling from both inside and outside the cilium
The regulatory GTPase Arl13b localizes to primary cilia, where it regulates Sonic hedgehog (Shh) signaling. Missense mutations in ARL13B can cause the ciliopathy Joubert syndrome (JS), and the mouse null allele is embryonic lethal. We used mouse embryonic fibroblasts as a system to determine the eff...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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The American Society for Cell Biology
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5170560/ https://www.ncbi.nlm.nih.gov/pubmed/27682584 http://dx.doi.org/10.1091/mbc.E16-03-0189 |
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author | Mariani, Laura E. Bijlsma, Maarten F. Ivanova, Anna I. Suciu, Sarah K. Kahn, Richard A. Caspary, Tamara |
author_facet | Mariani, Laura E. Bijlsma, Maarten F. Ivanova, Anna I. Suciu, Sarah K. Kahn, Richard A. Caspary, Tamara |
author_sort | Mariani, Laura E. |
collection | PubMed |
description | The regulatory GTPase Arl13b localizes to primary cilia, where it regulates Sonic hedgehog (Shh) signaling. Missense mutations in ARL13B can cause the ciliopathy Joubert syndrome (JS), and the mouse null allele is embryonic lethal. We used mouse embryonic fibroblasts as a system to determine the effects of Arl13b mutations on Shh signaling. We tested seven different mutants—three JS-causing variants, two point mutants predicted to alter guanine nucleotide handling, one that disrupts cilia localization, and one that prevents palmitoylation and thus membrane binding—in assays of transcriptional and nontranscriptional Shh signaling. We found that mutations disrupting Arl13b’s palmitoylation site, cilia localization signal, or GTPase handling altered the Shh response in distinct assays of transcriptional or nontranscriptional signaling. In contrast, JS-causing mutations in Arl13b did not affect Shh signaling in these same assays, suggesting that these mutations result in more subtle defects, likely affecting only a subset of signaling outputs. Finally, we show that restricting Arl13b from cilia interferes with its ability to regulate Shh-stimulated chemotaxis, despite previous evidence that cilia themselves are not required for this nontranscriptional Shh response. This points to a more complex relationship between the ciliary and nonciliary roles of this regulatory GTPase than previously envisioned. |
format | Online Article Text |
id | pubmed-5170560 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | The American Society for Cell Biology |
record_format | MEDLINE/PubMed |
spelling | pubmed-51705602017-01-30 Arl13b regulates Shh signaling from both inside and outside the cilium Mariani, Laura E. Bijlsma, Maarten F. Ivanova, Anna I. Suciu, Sarah K. Kahn, Richard A. Caspary, Tamara Mol Biol Cell Articles The regulatory GTPase Arl13b localizes to primary cilia, where it regulates Sonic hedgehog (Shh) signaling. Missense mutations in ARL13B can cause the ciliopathy Joubert syndrome (JS), and the mouse null allele is embryonic lethal. We used mouse embryonic fibroblasts as a system to determine the effects of Arl13b mutations on Shh signaling. We tested seven different mutants—three JS-causing variants, two point mutants predicted to alter guanine nucleotide handling, one that disrupts cilia localization, and one that prevents palmitoylation and thus membrane binding—in assays of transcriptional and nontranscriptional Shh signaling. We found that mutations disrupting Arl13b’s palmitoylation site, cilia localization signal, or GTPase handling altered the Shh response in distinct assays of transcriptional or nontranscriptional signaling. In contrast, JS-causing mutations in Arl13b did not affect Shh signaling in these same assays, suggesting that these mutations result in more subtle defects, likely affecting only a subset of signaling outputs. Finally, we show that restricting Arl13b from cilia interferes with its ability to regulate Shh-stimulated chemotaxis, despite previous evidence that cilia themselves are not required for this nontranscriptional Shh response. This points to a more complex relationship between the ciliary and nonciliary roles of this regulatory GTPase than previously envisioned. The American Society for Cell Biology 2016-11-15 /pmc/articles/PMC5170560/ /pubmed/27682584 http://dx.doi.org/10.1091/mbc.E16-03-0189 Text en © 2016 Mariani et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0). “ASCB®,” “The American Society for Cell Biology®,” and “Molecular Biology of the Cell®” are registered trademarks of The American Society for Cell Biology. |
spellingShingle | Articles Mariani, Laura E. Bijlsma, Maarten F. Ivanova, Anna I. Suciu, Sarah K. Kahn, Richard A. Caspary, Tamara Arl13b regulates Shh signaling from both inside and outside the cilium |
title | Arl13b regulates Shh signaling from both inside and outside the cilium |
title_full | Arl13b regulates Shh signaling from both inside and outside the cilium |
title_fullStr | Arl13b regulates Shh signaling from both inside and outside the cilium |
title_full_unstemmed | Arl13b regulates Shh signaling from both inside and outside the cilium |
title_short | Arl13b regulates Shh signaling from both inside and outside the cilium |
title_sort | arl13b regulates shh signaling from both inside and outside the cilium |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5170560/ https://www.ncbi.nlm.nih.gov/pubmed/27682584 http://dx.doi.org/10.1091/mbc.E16-03-0189 |
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