title: INPP5E regulates phosphoinositide-dependent cilia transition zone function.
abstract: Human ciliopathies, including Joubert syndrome (JBTS), arise from cilia dysfunction. The inositol polyphosphate 5-phosphatase INPP5E localizes to cilia and is mutated in JBTS. Murine Inpp5e ablation is embryonically lethal and recapitulates JBTS, including neural tube defects and polydactyly; however, the underlying defects in cilia signaling and the function of INPP5E at cilia are still emerging. We report Inpp5e-/-embryos exhibit aberrant Hedgehog-dependent patterning with reduced Hedgehog signaling. Using mouse genetics, we show increasing Hedgehog signaling via Smoothened M2 expression rescues some Inpp5e-/-ciliopathy phenotypes and "normalizes" Hedgehog signaling. INPP5E's phosphoinositide substrates PI(4,5)P2and PI(3,4,5)P3accumulated at the transition zone (TZ) in Hedgehog-stimulated Inpp5e-/-cells, which was associated with reduced recruitment of TZ scaffolding proteins and reduced Smoothened levels at cilia. Expression of wild-type, but not 5-phosphatase-dead, INPP5E restored TZ molecular organization and Smoothened accumulation at cilia. Therefore, we identify INPP5E as an essential point of convergence between Hedgehog and phosphoinositide signaling at cilia that maintains TZ function and Hedgehog-dependent embryonic development.
authors.affiliation: Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Dyson
authors.affiliation: Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Sarah E
authors.identifier: http://orcid.org/0000-0002-5075-8851
authors.initials: SE
authors.lastname: Conduit
authors.affiliation: Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Sandra J
authors.identifier: http://orcid.org/0000-0002-9372-5232
authors.initials: SJ
authors.lastname: Feeney
authors.affiliation: Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Sandra
authors.identifier: http://orcid.org/0000-0002-3043-4411
authors.initials: S
authors.lastname: Hakim
authors.affiliation: Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Tia
authors.initials: T
authors.lastname: DiTommaso
authors.affiliation: Monash Micro Imaging, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Alex J
authors.identifier: http://orcid.org/0000-0002-6278-7211
authors.initials: AJ
authors.lastname: Fulcher
authors.affiliation: Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Absorn
authors.identifier: http://orcid.org/0000-0003-1896-437X
authors.initials: A
authors.lastname: Sriratana
authors.affiliation: Monash Micro Imaging, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Georg
authors.identifier: http://orcid.org/0000-0003-3596-2288
authors.initials: G
authors.lastname: Ramm
authors.affiliation: Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Kristy A
authors.initials: KA
authors.lastname: Horan
authors.affiliation: Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Rajendra
authors.initials: R
authors.lastname: Gurung
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia.
authors.forename: Carol
authors.identifier: http://orcid.org/0000-0002-7225-3803
authors.initials: C
authors.lastname: Wicking
authors.affiliation: Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia.|Development and Stem Cells Program, Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Ian
authors.identifier: http://orcid.org/0000-0002-1727-7829
authors.initials: I
authors.lastname: Smyth
authors.affiliation: Cancer Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia christina.mitchell@monash.edu.
authors.forename: Christina A
authors.identifier: http://orcid.org/0000-0001-9372-3192
authors.initials: CA
authors.lastname: Mitchell
mesh_terms: D000015:Abnormalities, Multiple / Q000201:enzymology* / Q000235:genetics; D000818:Animals; D002460:Cell Line; D002531:Cerebellum / Q000002:abnormalities* / Q000201:enzymology; D002923:Cilia / Q000201:enzymology*; D004195:Disease Models, Animal; D004622:Embryo, Mammalian / Q000201:enzymology*; D005124:Eye Abnormalities / Q000201:enzymology* / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D020022:Genetic Predisposition to Disease; D053823:Hedgehog Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D052177:Kidney Diseases, Cystic / Q000201:enzymology* / Q000235:genetics; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010641:Phenotype; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D012160:Retina / Q000002:abnormalities* / Q000201:enzymology; D055213:Retinal Pigment Epithelium / Q000201:enzymology*; D015290:Second Messenger Systems; D000072086:Smoothened Receptor / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D000075746:Zinc Finger Protein Gli2; D000099182:Phosphoinositide 5-Phosphatases
chemical_list: D053823:Hedgehog Proteins; D051741:Kruppel-Like Transcription Factors; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010744:Phosphoric Monoester Hydrolases; D000072086:Smoothened Receptor; D000075746:Zinc Finger Protein Gli2; D000099182:Phosphoinositide 5-Phosphatases; C000618551:Gli2 protein, mouse; C491022:Smo protein, mouse; C060974:phosphatidylinositol 3,4,5-triphosphate