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Yoshida S, Kawamura A, Aoki K, Wiriyasermkul P, Sugimoto S, Tomiyoshi J, Tajima A, Ishida Y, Katoh Y, Tsukada T, Tsuneoka Y, Yamada K, Nagamori S, Nakayama K, Yoshida K. Positive regulation of Hedgehog signaling via phosphorylation of GLI2/GLI3 by DYRK2 kinase. Proc Natl Acad Sci U S A 2024; 121:e2320070121. [PMID: 38968120 PMCID: PMC11252808 DOI: 10.1073/pnas.2320070121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 06/02/2024] [Indexed: 07/07/2024] Open
Abstract
Hedgehog (Hh) signaling, an evolutionarily conserved pathway, plays an essential role in development and tumorigenesis, making it a promising drug target. Multiple negative regulators are known to govern Hh signaling; however, how activated Smoothened (SMO) participates in the activation of downstream GLI2 and GLI3 remains unclear. Herein, we identified the ciliary kinase DYRK2 as a positive regulator of the GLI2 and GLI3 transcription factors for Hh signaling. Transcriptome and interactome analyses demonstrated that DYRK2 phosphorylates GLI2 and GLI3 on evolutionarily conserved serine residues at the ciliary base, in response to activation of the Hh pathway. This phosphorylation induces the dissociation of GLI2/GLI3 from suppressor, SUFU, and their translocation into the nucleus. Loss of Dyrk2 in mice causes skeletal malformation, but neural tube development remains normal. Notably, DYRK2-mediated phosphorylation orchestrates limb development by controlling cell proliferation. Taken together, the ciliary kinase DYRK2 governs the activation of Hh signaling through the regulation of two processes: phosphorylation of GLI2 and GLI3 downstream of SMO and cilia formation. Thus, our findings of a unique regulatory mechanism of Hh signaling expand understanding of the control of Hh-associated diseases.
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Affiliation(s)
- Saishu Yoshida
- Department of Biochemistry, The Jikei University School of Medicine, Tokyo105-8461, Japan
| | - Akira Kawamura
- Department of Biochemistry, The Jikei University School of Medicine, Tokyo105-8461, Japan
| | - Katsuhiko Aoki
- Radioisotope Research Facilities, The Jikei University School of Medicine, Tokyo105-8461, Japan
| | - Pattama Wiriyasermkul
- Center for Stable Isotope Medical Research, The Jikei University School of Medicine, Tokyo105-8461, Japan
- Department of Laboratory Medicine, The Jikei University School of Medicine, Tokyo105-8461, Japan
| | - Shinya Sugimoto
- Department of Bacteriology, The Jikei University School of Medicine, Tokyo105-8461, Japan
- Center for Biofilm Science and Technology, The Jikei University School of Medicine, Tokyo105-8461, Japan
- Laboratory of Amyloid Regulation, The Jikei University School of Medicine, Tokyo105-8461, Japan
| | - Junnosuke Tomiyoshi
- Department of Biochemistry, The Jikei University School of Medicine, Tokyo105-8461, Japan
| | - Ayasa Tajima
- Center for Stable Isotope Medical Research, The Jikei University School of Medicine, Tokyo105-8461, Japan
- Department of Molecular Biology, The Jikei University School of Medicine, Tokyo105-8461, Japan
| | - Yamato Ishida
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto606-8501, Japan
| | - Yohei Katoh
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto606-8501, Japan
| | - Takehiro Tsukada
- Department of Biomolecular Science, Toho University, Chiba274-8510, Japan
| | - Yousuke Tsuneoka
- Department of Anatomy, Faculty of Medicine, Toho University, Tokyo143-8540, Japan
| | - Kohji Yamada
- Department of Biochemistry, The Jikei University School of Medicine, Tokyo105-8461, Japan
| | - Shushi Nagamori
- Center for Stable Isotope Medical Research, The Jikei University School of Medicine, Tokyo105-8461, Japan
- Department of Laboratory Medicine, The Jikei University School of Medicine, Tokyo105-8461, Japan
| | - Kazuhisa Nakayama
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto606-8501, Japan
| | - Kiyotsugu Yoshida
- Department of Biochemistry, The Jikei University School of Medicine, Tokyo105-8461, Japan
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Yoshida S, Tsuneoka Y, Tsukada T, Nakakura T, Kawamura A, Kai W, Yoshida K. Primary Cilia are Required for Cell-Type Determination and Angiogenesis in Pituitary Development. Endocrinology 2024; 165:bqae085. [PMID: 39001875 DOI: 10.1210/endocr/bqae085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/26/2024] [Accepted: 07/11/2024] [Indexed: 07/15/2024]
Abstract
The functional maturation of the pituitary gland requires adequate cell differentiation and vascular network formation. Although spatiotemporal signaling and transcription factors are known to govern pituitary development, the involvement of primary cilia, nonmoving hair-like organelles, remains unclear. In this study, we uncovered the contribution of primary cilia to cell-type determination and vascular network formation during pituitary development. Homozygous knockout mice lacking a ciliary kinase, Dyrk2-/-, exhibit abnormalities in ciliary structure and pituitary hypoplasia, accompanied by varying degrees of failure in differentiation among all types of hormone-producing cells in the anterior lobe. Aberrations in cell differentiation in Dyrk2-/- mice arise from a decrease in the expression of crucial transcription factors, Lhx4, Lhx3, and Prop1, resulting from the inactivity of Hedgehog (Hh) signaling during the early stages of development. Furthermore, the loss of Dyrk2 results in vascular system abnormalities during the middle to late stages of development. Mechanistically, transcriptome analyses revealed the downregulation of vitronectin-integrin αvβ3-VEGFR2 signaling, essential for orchestrating vascular development. Collectively, our findings demonstrate that primary cilia play a pivotal role as critical regulators of cell survival, cell determination, and angiogenesis during pituitary gland development through the activation of Hh signaling. These findings expand our understanding of the potential link between pituitary dysfunction in human disorders and ciliopathies.
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Affiliation(s)
- Saishu Yoshida
- Department of Biochemistry, The Jikei University School of Medicine, Tokyo 105-8461, Japan
- Department of Biomolecular Science, Toho University, Chiba 274-8510, Japan
| | - Yousuke Tsuneoka
- Department of Anatomy, Faculty of Medicine, Toho University, Tokyo 143-8540, Japan
| | - Takehiro Tsukada
- Department of Biomolecular Science, Toho University, Chiba 274-8510, Japan
| | - Takashi Nakakura
- Department of Anatomy, Graduate School of Medicine, Teikyo University, Tokyo 173-8605, Japan
| | - Akira Kawamura
- Department of Biochemistry, The Jikei University School of Medicine, Tokyo 105-8461, Japan
| | - Wataru Kai
- Department of Biochemistry, The Jikei University School of Medicine, Tokyo 105-8461, Japan
| | - Kiyotsugu Yoshida
- Department of Biochemistry, The Jikei University School of Medicine, Tokyo 105-8461, Japan
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Kumar R, Francis V, Kulasekaran G, Khan M, Armstrong GAB, McPherson PS. A cell-based GEF assay reveals new substrates for DENN domains and a role for DENND2B in primary ciliogenesis. SCIENCE ADVANCES 2022; 8:eabk3088. [PMID: 35196081 PMCID: PMC8865772 DOI: 10.1126/sciadv.abk3088] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 12/30/2021] [Indexed: 06/14/2023]
Abstract
Primary cilia are sensory antennae crucial for cell and organism development, and defects in their biogenesis cause ciliopathies. Ciliogenesis involves membrane trafficking mediated by small guanosine triphosphatases (GTPases) including Rabs, molecular switches activated by guanine nucleotide exchange factors (GEFs). The largest family of Rab GEFs is the DENN domain-bearing proteins. Here, we screen all 60 Rabs against two major DENN domain families using a cellular GEF assay, uncovering 19 novel DENN/Rab pairs. The screen reveals Rab10 as a substrate for DENND2B, a protein previously implicated in cancer and severe mental retardation. Through activation of Rab10, DENND2B represses the formation of primary cilia. Through a second pathway, DENND2B functions as a GEF for RhoA to control the length of primary cilia. This work thus identifies an unexpected diversity in DENN domain-mediated activation of Rabs, a previously unidentified non-Rab substrate for a DENN domain, and a new regulatory protein in primary ciliogenesis.
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Kinnebrew M, Johnson KA, Radhakrishnan A, Rohatgi R. Measuring and Manipulating Membrane Cholesterol for the Study of Hedgehog Signaling. Methods Mol Biol 2022; 2374:73-87. [PMID: 34562244 PMCID: PMC8819901 DOI: 10.1007/978-1-0716-1701-4_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cholesterol is an abundant lipid in mammalian plasma membranes that regulates the reception of the Hedgehog (Hh) signal in target cells. In vertebrates, cell-surface organelles called primary cilia function as compartments for the propagation of Hh signals. Recent structural, biochemical, and cell-biological studies have led to the model that Patched-1 (PTCH1), the receptor for Hh ligands, uses its transporter-like activity to lower cholesterol accessibility in the membrane surrounding primary cilia. Cholesterol restriction at cilia may represent the long-sought-after mechanism by which PTCH1 inhibits Smoothened (SMO), a cholesterol-responsive transmembrane protein of the G protein-coupled receptor superfamily that transmits the Hh signal across the membrane.Protein probes based on microbial cholesterol-binding proteins revealed that PTCH1 controls only a subset of the total cholesterol molecules, a biochemically defined fraction called accessible cholesterol. The accessible cholesterol pool coexists (and exchanges) with a pool of sequestered cholesterol, which is bound to phospholipids like sphingomyelin. In this chapter, we describe how to measure the accessible and sequestered cholesterol pools in live cells with protein-based probes. We discuss how to purify and fluorescently label these probes for use in flow cytometry and microscopy-based measurements of the cholesterol pools. Additionally, we describe how to modulate accessible cholesterol levels to determine if this pool regulates Hh signaling (or any other cellular process of interest).
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Affiliation(s)
- Maia Kinnebrew
- Department of Medicine and Biochemistry, Stanford University School of Medicine, Stanford, CA, USA
| | - Kristen A Johnson
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Arun Radhakrishnan
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Rajat Rohatgi
- Department of Medicine and Biochemistry, Stanford University School of Medicine, Stanford, CA, USA.
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Inactivation of Hedgehog signal transduction in adult astrocytes results in region-specific blood-brain barrier defects. Proc Natl Acad Sci U S A 2021; 118:2017779118. [PMID: 34417306 DOI: 10.1073/pnas.2017779118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
In this study, we use molecular genetic approaches to clarify the role of the Hedgehog (Hh) pathway in regulating the blood-brain/spinal cord barrier (BBB) in the adult mouse central nervous system (CNS). Our work confirms and extends prior studies to demonstrate that astrocytes are the predominant cell type in the adult CNS that transduce Hh signaling, revealed by the expression of Gli1, a target gene of the canonical pathway that is activated in cells receiving Hh, and other key pathway transduction components. Gli1+ (Hh-responsive) astrocytes are distributed in specific regions of the CNS parenchyma, including layers 4/5/6 of the neocortex, hypothalamus, thalamus, and spinal cord, among others. Notably, although BBB properties in endothelial cells are normally regulated by both paracellular and transcellular mechanisms, conditional inactivation of Hh signaling in astrocytes results in transient, region-specific BBB defects that affect transcytosis but not paracellular diffusion. These findings stand in contrast to prior studies that implicated astrocytes as a source of Sonic hedgehog that limited extravasation via both mechanisms [J. I. Alvarez et al., Science 334, 1727-1731 (2011)]. Furthermore, using three distinct Cre driver lines as well as pharmacological approaches to inactivate Hh-pathway transduction globally in CNS astrocytes, we find that these specific BBB defects are only detected in the rostral hypothalamus and spinal cord but not the cortex or other regions where Gli1+ astrocytes are found. Together, our data show that Gli1+ Hh-responsive astrocytes have regionally distinct molecular and functional properties and that the pathway is required to maintain BBB properties in specific regions of the adult mammalian CNS.
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6
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Markiewicz Ł, Uśpieński T, Baran B, Niedziółka SM, Niewiadomski P. Xpo7 negatively regulates Hedgehog signaling by exporting Gli2 from the nucleus. Cell Signal 2021; 80:109907. [PMID: 33383157 DOI: 10.1016/j.cellsig.2020.109907] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 12/22/2020] [Accepted: 12/27/2020] [Indexed: 01/01/2023]
Abstract
Dynamic bidirectional transport between the nucleus and the cytoplasm is critical for the regulation of many transcription factors, whose levels inside the nucleus must be tightly controlled. Efficient shuttling across the nuclear membrane is especially crucial with regard to the Hedgehog (Hh) pathway, where the transcriptional signal depends on the fine balance between the amounts of Gli protein activator and repressor forms in the nucleus. The nuclear export machinery prevents the unchecked nuclear accumulation of Gli proteins, but the mechanistic insight into this process is limited. We show that the atypical exportin Xpo7 functions as a major nuclear export receptor that actively excludes Gli2 from the nucleus and controls the outcome of Hh signaling. We show that Xpo7 interacts with several domains of Gli2 and that this interaction is modulated by SuFu, a key negative regulator of Hh signaling. Our data pave the way for a more complete understanding of the nuclear shuttling of Gli proteins and the regulation of their transcriptional activity.
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Affiliation(s)
- Łukasz Markiewicz
- Laboratory of Molecular and Cellular Signaling, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Tomasz Uśpieński
- Laboratory of Molecular and Cellular Signaling, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Brygida Baran
- Laboratory of Molecular and Cellular Signaling, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Sylwia M Niedziółka
- Laboratory of Molecular and Cellular Signaling, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Paweł Niewiadomski
- Laboratory of Molecular and Cellular Signaling, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland.
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Yoshida S, Aoki K, Fujiwara K, Nakakura T, Kawamura A, Yamada K, Ono M, Yogosawa S, Yoshida K. The novel ciliogenesis regulator DYRK2 governs Hedgehog signaling during mouse embryogenesis. eLife 2020; 9:e57381. [PMID: 32758357 PMCID: PMC7410489 DOI: 10.7554/elife.57381] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 07/14/2020] [Indexed: 12/20/2022] Open
Abstract
Mammalian Hedgehog (Hh) signaling plays key roles in embryogenesis and uniquely requires primary cilia. Functional analyses of several ciliogenesis-related genes led to the discovery of the developmental diseases known as ciliopathies. Hence, identification of mammalian factors that regulate ciliogenesis can provide insight into the molecular mechanisms of embryogenesis and ciliopathy. Here, we demonstrate that DYRK2 acts as a novel mammalian ciliogenesis-related protein kinase. Loss of Dyrk2 in mice causes suppression of Hh signaling and results in skeletal abnormalities during in vivo embryogenesis. Deletion of Dyrk2 induces abnormal ciliary morphology and trafficking of Hh pathway components. Mechanistically, transcriptome analyses demonstrate down-regulation of Aurka and other disassembly genes following Dyrk2 deletion. Taken together, the present study demonstrates for the first time that DYRK2 controls ciliogenesis and is necessary for Hh signaling during mammalian development.
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Affiliation(s)
- Saishu Yoshida
- Department of Biochemistry, The Jikei University School of MedicineTokyoJapan
| | - Katsuhiko Aoki
- Department of Biochemistry, The Jikei University School of MedicineTokyoJapan
| | - Ken Fujiwara
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of MedicineTochigiJapan
| | - Takashi Nakakura
- Department of Anatomy, Graduate School of Medicine, Teikyo UniversityTokyoJapan
| | - Akira Kawamura
- Department of Biochemistry, The Jikei University School of MedicineTokyoJapan
| | - Kohji Yamada
- Department of Biochemistry, The Jikei University School of MedicineTokyoJapan
| | - Masaya Ono
- Department of Clinical Proteomics, National Cancer Center Research InstituteTokyoJapan
| | - Satomi Yogosawa
- Department of Biochemistry, The Jikei University School of MedicineTokyoJapan
| | - Kiyotsugu Yoshida
- Department of Biochemistry, The Jikei University School of MedicineTokyoJapan
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8
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Massa F, Tammaro R, Prado MA, Cesana M, Lee BH, Finley D, Franco B, Morleo M. The deubiquitinating enzyme Usp14 controls ciliogenesis and Hedgehog signaling. Hum Mol Genet 2020; 28:764-777. [PMID: 30388222 DOI: 10.1093/hmg/ddy380] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 10/11/2018] [Accepted: 10/16/2018] [Indexed: 12/20/2022] Open
Abstract
Primary cilia are hair-like organelles that play crucial roles in vertebrate development, organogenesis and when dysfunctional result in pleiotropic human genetic disorders called ciliopathies, characterized by overlapping phenotypes, such as renal and hepatic cysts, skeletal defects, retinal degeneration and central nervous system malformations. Primary cilia act as communication hubs to transfer extracellular signals into intracellular responses and are essential for Hedgehog (Hh) signal transduction in mammals. Despite the renewed interest in this ancient organelle of growing biomedical importance, the molecular mechanisms that trigger cilia formation, extension and ciliary signal transduction are still not fully understood. Here we provide, for the first time, evidence that the deubiquitinase ubiquitin-specific protease-14 (Usp14), a major regulator of the ubiquitin proteasome system (UPS), controls ciliogenesis, cilia elongation and Hh signal transduction. Moreover, we show that pharmacological inhibition of Usp14 positively affects Hh signal transduction in a model of autosomal dominant polycystic kidney disease. These findings provide new insight into the spectrum of action of UPS in cilia biology and may provide novel opportunities for therapeutic intervention in human conditions associated with ciliary dysfunction.
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Affiliation(s)
- Filomena Massa
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli, Naples, Italy
| | - Roberta Tammaro
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli, Naples, Italy
| | - Miguel A Prado
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Marcella Cesana
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli, Naples, Italy
| | - Byung-Hoon Lee
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA.,Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Korea
| | - Daniel Finley
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Brunella Franco
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli, Naples, Italy.,Medical Genetics, Department of Translational Medicine, University of Naples Federico II, Via Sergio Pansini 5, Naples, Italy
| | - Manuela Morleo
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli, Naples, Italy.,Medical Genetics, Department of Translational Medicine, University of Naples Federico II, Via Sergio Pansini 5, Naples, Italy
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9
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Dhekne HS, Yanatori I, Gomez RC, Tonelli F, Diez F, Schüle B, Steger M, Alessi DR, Pfeffer SR. A pathway for Parkinson's Disease LRRK2 kinase to block primary cilia and Sonic hedgehog signaling in the brain. eLife 2018; 7:40202. [PMID: 30398148 PMCID: PMC6219843 DOI: 10.7554/elife.40202] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 10/11/2018] [Indexed: 12/14/2022] Open
Abstract
Parkinson’s disease-associated LRRK2 kinase phosphorylates multiple Rab GTPases, including Rab8A and Rab10. We show here that LRRK2 kinase interferes with primary cilia formation in cultured cells, human LRRK2 G2019S iPS cells and in the cortex of LRRK2 R1441C mice. Rab10 phosphorylation strengthens its intrinsic ability to block ciliogenesis by enhancing binding to RILPL1. Importantly, the ability of LRRK2 to interfere with ciliogenesis requires both Rab10 and RILPL1 proteins. Pathogenic LRRK2 influences the ability of cells to respond to cilia-dependent, Hedgehog signaling as monitored by Gli1 transcriptional activation. Moreover, cholinergic neurons in the striatum of LRRK2 R1441C mice show decreased ciliation, which will decrease their ability to sense Sonic hedgehog in a neuro-protective circuit that supports dopaminergic neurons. These data reveal a molecular pathway for regulating cilia function that likely contributes to Parkinson’s disease-specific pathology. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
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Affiliation(s)
- Herschel S Dhekne
- Department of Biochemistry, Stanford University School of Medicine, Stanford, United States
| | - Izumi Yanatori
- Department of Biochemistry, Stanford University School of Medicine, Stanford, United States
| | - Rachel C Gomez
- Department of Biochemistry, Stanford University School of Medicine, Stanford, United States
| | - Francesca Tonelli
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Federico Diez
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Birgitt Schüle
- Parkinson's Institute and Clinical Center, California, United States
| | - Martin Steger
- Department of Proteomics and Signal Transduction, Max-Planck-Institute of Biochemistry, Martinsried, Germany
| | - Dario R Alessi
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Suzanne R Pfeffer
- Department of Biochemistry, Stanford University School of Medicine, Stanford, United States
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Rosengren T, Larsen LJ, Pedersen LB, Christensen ST, Møller LB. TSC1 and TSC2 regulate cilia length and canonical Hedgehog signaling via different mechanisms. Cell Mol Life Sci 2018; 75:2663-2680. [PMID: 29396625 PMCID: PMC6003990 DOI: 10.1007/s00018-018-2761-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 01/03/2018] [Accepted: 01/24/2018] [Indexed: 01/22/2023]
Abstract
Primary cilia are sensory organelles that coordinate multiple cellular signaling pathways, including Hedgehog (HH), Wingless/Int (WNT) and Transforming Growth Factor-β (TGF-β) signaling. Similarly, primary cilia have been implicated in regulation of mTOR signaling, in which Tuberous Sclerosis Complex proteins 1 and 2 (TSC1/2) negatively regulate protein synthesis by inactivating the mTOR complex 1 (mTORC1) at energy limiting states. Here we report that TSC1 and TSC2 regulate Smoothened (SMO)-dependent HH signaling in mouse embryonic fibroblasts (MEFs). Reduced SMO-dependent expression of Gli1 was demonstrated in both Tsc1-/- and Tsc2-/- cells, and we found that Tsc1 is required for TGF-β induced phosphorylation of SMAD2/3 and subsequent expression of the HH signaling effector and transcription factor GLI2. Hedgehog signaling was restored in Tsc1-/- cells after exogenous expression of Gli2, whereas rapamycin restored HH signaling in Tsc2-/- cells. Furthermore, we observed that Tsc1-/- MEFs display significantly elongated cilia, whereas cilia in Tsc2-/- MEFs were shorter than normal. The elongated cilium phenotype of Tsc1-/- MEFs is likely due to increased mTORC1-dependent autophagic flux observed in these cells, as both the autophagic flux and the cilia length phenotype was restored by rapamycin. In addition, ciliary length control in Tsc1-/- MEFs was also influenced by reduced expression of Gli2, which compromised expression of Wnt5a that normally promotes cilia disassembly. In summary, our results support distinct functions of Tsc1 and Tsc2 in cellular signaling as the two genes affect ciliary length control and HH signaling via different mechanisms.
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Affiliation(s)
- Thomas Rosengren
- Applied Human Molecular Genetics, Clinical Genetic Clinic, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Gl. Landevej 7, 2600, Glostrup, Denmark
| | - Lasse Jonsgaard Larsen
- Applied Human Molecular Genetics, Clinical Genetic Clinic, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Gl. Landevej 7, 2600, Glostrup, Denmark
| | - Lotte Bang Pedersen
- Department of Biology, The August Krogh Building, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen, Denmark
| | - Søren Tvorup Christensen
- Department of Biology, The August Krogh Building, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen, Denmark
| | - Lisbeth Birk Møller
- Applied Human Molecular Genetics, Clinical Genetic Clinic, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Gl. Landevej 7, 2600, Glostrup, Denmark.
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