1
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Jung JH, Lee H, Jeon J, Lee YJ, Nada H, Kim M, Lee H, Bhattarai D, Lee K, Ko HW. A novel indole derivative, 2-{3-[1-(benzylsulfonyl)piperidin-4-yl]-2-methyl-1H-indol-1-yl}-1-(pyrrolidin-1-yl)ethenone, suppresses hedgehog signaling and drug-resistant tumor growth. Arch Pharm (Weinheim) 2024:e2400218. [PMID: 38963677 DOI: 10.1002/ardp.202400218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 06/07/2024] [Accepted: 06/10/2024] [Indexed: 07/05/2024]
Abstract
The Hedgehog (Hh) signaling pathway plays important roles in various physiological functions. Several malignancies, such as basal cell carcinoma (BCC) and medulloblastoma (MB), have been linked to the aberrant activation of Hh signaling. Although therapeutic drugs have been developed to inhibit Hh pathway-dependent cancer growth, drug resistance remains a major obstacle in cancer treatment. Here, we show that the newly identified, 2-{3-[1-(benzylsulfonyl)-1,2,3,6-tetrahydropyridin-4-yl]-2-methyl-1H-indol-1-yl}-1-(pyrrolidin-1-yl)ethenone analog (LKD1214) exhibits comparable potency to vismodegib in suppressing the Hh pathway activation. LKD1214 represses Smoothened (SMO) activity by blocking its ciliary translocation. Interestingly, we also identified that it has a distinctive binding interface with SMO compared with other SMO-regulating chemicals. Notably, it maintains an inhibitory activity against the SmoD477H mutant, as observed in a patient with vismodegib-resistant BCC. Furthermore, LKD1214 inhibits tumor growth in the mouse model of MB. Collectively, these findings suggest that LKD1214 has the therapeutic potential to overcome drug-resistance in Hh-dependent cancers.
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Affiliation(s)
- Joo Hyun Jung
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
- College of Pharmacy, Dongguk University, Goyangsi, Gyeonggido, Korea
| | - Hwayoung Lee
- College of Pharmacy, Dongguk University, Goyangsi, Gyeonggido, Korea
| | - Jiyeon Jeon
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Yoon Ji Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
- College of Pharmacy, Dongguk University, Goyangsi, Gyeonggido, Korea
| | - Hossam Nada
- College of Pharmacy, Dongguk University, Goyangsi, Gyeonggido, Korea
| | - Minkyoung Kim
- College of Pharmacy, Dongguk University, Goyangsi, Gyeonggido, Korea
| | - Hankyu Lee
- College of Pharmacy, Dongguk University, Goyangsi, Gyeonggido, Korea
| | - Deepak Bhattarai
- College of Pharmacy, Dongguk University, Goyangsi, Gyeonggido, Korea
| | - Kyeong Lee
- College of Pharmacy, Dongguk University, Goyangsi, Gyeonggido, Korea
| | - Hyuk Wan Ko
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
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2
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Hilgendorf KI, Myers BR, Reiter JF. Emerging mechanistic understanding of cilia function in cellular signalling. Nat Rev Mol Cell Biol 2024; 25:555-573. [PMID: 38366037 PMCID: PMC11199107 DOI: 10.1038/s41580-023-00698-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2023] [Indexed: 02/18/2024]
Abstract
Primary cilia are solitary, immotile sensory organelles present on most cells in the body that participate broadly in human health, physiology and disease. Cilia generate a unique environment for signal transduction with tight control of protein, lipid and second messenger concentrations within a relatively small compartment, enabling reception, transmission and integration of biological information. In this Review, we discuss how cilia function as signalling hubs in cell-cell communication using three signalling pathways as examples: ciliary G-protein-coupled receptors (GPCRs), the Hedgehog (Hh) pathway and polycystin ion channels. We review how defects in these ciliary signalling pathways lead to a heterogeneous group of conditions known as 'ciliopathies', including metabolic syndromes, birth defects and polycystic kidney disease. Emerging understanding of these pathways' transduction mechanisms reveals common themes between these cilia-based signalling pathways that may apply to other pathways as well. These mechanistic insights reveal how cilia orchestrate normal and pathophysiological signalling outputs broadly throughout human biology.
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Affiliation(s)
- Keren I Hilgendorf
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA.
| | - Benjamin R Myers
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA.
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, UT, USA.
- Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, UT, USA.
| | - Jeremy F Reiter
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
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3
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Han S, Hu Y, Jia D, Lv Y, Liu M, Wang D, Chao J, Xia X, Wang Q, Liu P, Cai Y, Ren X. IFT27 regulates the long-term maintenance of photoreceptor outer segments in zebrafish. Gene 2024; 905:148237. [PMID: 38310983 DOI: 10.1016/j.gene.2024.148237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/22/2024] [Accepted: 01/30/2024] [Indexed: 02/06/2024]
Abstract
Approximately a quarter of Retinitis Pigmentosa (RP) is caused by mutations in transport-related genes in cilia. IFT27 (Intraflagellar Transport 27), a core component of the ciliary intraflagellar transport (IFT) system, has been implicated as a significant pathogenic gene in RP. The pathogenic mechanisms and subsequent pathology related to IFT27 mutations in RP are largely obscure. Here, we utilized TALEN technology to create an ift27 knockout (ift27-/-) zebrafish model. Electroretinography (ERG) detection showed impaired vision in this model. Histopathological examinations disclosed that ift27 mutations cause progressive degeneration of photoreceptors in zebrafish, and this degeneration was late-onset. Immunofluorescence labeling of outer segments showed that rods degenerated before cones, aligning with the conventional characterization of RP. In cultured human retinal pigment epithelial cells, we found that IFT27 was involved in maintaining ciliary morphology. Furthermore, decreased IFT27 expression resulted in the inhibition of the Hedgehog (Hh) signaling pathway, including decreased expression of key factors in the Hh pathway and abnormal localization of the ciliary mediator Gli2. In summary, we generated an ift27-/- zebrafish line with retinal degeneration which mimicked the symptoms of RP patients, highlighting IFT27's integral role in the long-term maintenance of cilia via the Hh signaling pathway. This work may furnish new insights into the treatment or delay of RP caused by IFT27 mutations.
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Affiliation(s)
- Shanshan Han
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, Hubei, China; College of Basic Medical Sciences, China Three Gorges University, Yichang 443002, Hubei, China.
| | - Yue Hu
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, Hubei, China; College of Basic Medical Sciences, China Three Gorges University, Yichang 443002, Hubei, China
| | - Danna Jia
- Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan, 030032, China
| | - Yuexia Lv
- Prenatal Diagnosis Center, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, China
| | - Mugen Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Decheng Wang
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, Hubei, China; College of Basic Medical Sciences, China Three Gorges University, Yichang 443002, Hubei, China
| | - Jin Chao
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, Hubei, China; College of Basic Medical Sciences, China Three Gorges University, Yichang 443002, Hubei, China
| | - Xuan Xia
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, Hubei, China; College of Basic Medical Sciences, China Three Gorges University, Yichang 443002, Hubei, China
| | - Qiong Wang
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, Hubei, China; College of Basic Medical Sciences, China Three Gorges University, Yichang 443002, Hubei, China
| | - Pei Liu
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, Hubei, China; College of Basic Medical Sciences, China Three Gorges University, Yichang 443002, Hubei, China
| | - Yu Cai
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, Hubei, China; College of Basic Medical Sciences, China Three Gorges University, Yichang 443002, Hubei, China
| | - Xiang Ren
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China.
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Mohd Rafiq N, Fujise K, Rosenfeld MS, Xu P, De Camilli P. Parkinsonism Sac domain mutation in Synaptojanin-1 affects ciliary properties in iPSC-derived dopaminergic neurons. Proc Natl Acad Sci U S A 2024; 121:e2318943121. [PMID: 38635628 PMCID: PMC11047088 DOI: 10.1073/pnas.2318943121] [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: 11/06/2023] [Accepted: 03/04/2024] [Indexed: 04/20/2024] Open
Abstract
Synaptojanin-1 (SJ1) is a major neuronal-enriched PI(4, 5)P2 4- and 5-phosphatase implicated in the shedding of endocytic factors during endocytosis. A mutation (R258Q) that impairs selectively its 4-phosphatase activity causes Parkinsonism in humans and neurological defects in mice (SJ1RQKI mice). Studies of these mice showed, besides an abnormal assembly state of endocytic factors at synapses, the presence of dystrophic nerve terminals selectively in a subset of nigro-striatal dopamine (DA)-ergic axons, suggesting a special lability of DA neurons to the impairment of SJ1 function. Here we have further investigated the impact of SJ1 on DA neurons using iPSC-derived SJ1 KO and SJ1RQKI DA neurons and their isogenic controls. In addition to the expected enhanced clustering of endocytic factors in nerve terminals, we observed in both SJ1 mutant neuronal lines increased cilia length. Further analysis of cilia of SJ1RQDA neurons revealed abnormal accumulation of the Ca2+ channel Cav1.3 and of ubiquitin chains, suggesting a defect in the clearing of ubiquitinated proteins at the ciliary base, where a focal concentration of SJ1 was observed. We suggest that SJ1 may contribute to the control of ciliary protein dynamics in DA neurons, with implications on cilia-mediated signaling.
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Affiliation(s)
- Nisha Mohd Rafiq
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT06510
- Department of Cell biology, Yale University School of Medicine, New Haven, CT06510
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT06510
- Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD20815
| | - Kenshiro Fujise
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT06510
- Department of Cell biology, Yale University School of Medicine, New Haven, CT06510
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT06510
- Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD20815
| | - Martin Shaun Rosenfeld
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT06510
- Department of Cell biology, Yale University School of Medicine, New Haven, CT06510
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT06510
- Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD20815
| | - Peng Xu
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT06510
- Department of Cell biology, Yale University School of Medicine, New Haven, CT06510
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT06510
- Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD20815
| | - Pietro De Camilli
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT06510
- Department of Cell biology, Yale University School of Medicine, New Haven, CT06510
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT06510
- Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD20815
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Walker MF, Zhang J, Steiner W, Ku PI, Zhu JF, Michaelson Z, Yen YC, Lee A, Long AB, Casey MJ, Poddar A, Nelson IB, Arveseth CD, Nagel F, Clough R, LaPotin S, Kwan KM, Schulz S, Stewart RA, Tesmer JJG, Caspary T, Subramanian R, Ge X, Myers BR. GRK2 Kinases in the Primary Cilium Initiate SMOOTHENED-PKA Signaling in the Hedgehog Cascade. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.10.540226. [PMID: 37214942 PMCID: PMC10197709 DOI: 10.1101/2023.05.10.540226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
During Hedgehog (Hh) signal transduction in development and disease, the atypical G protein-coupled receptor (GPCR) SMOOTHENED (SMO) communicates with GLI transcription factors by binding the protein kinase A catalytic subunit (PKA-C) and physically blocking its enzymatic activity. Here we show that GPCR kinase 2 (GRK2) orchestrates this process during endogenous Hh pathway activation in the vertebrate primary cilium. Upon SMO activation, GRK2 rapidly relocalizes from the ciliary base to the shaft, triggering SMO phosphorylation and PKA-C interaction. Reconstitution studies reveal that GRK2 phosphorylation enables active SMO to bind PKA-C directly. Lastly, the SMO-GRK2-PKA pathway underlies Hh signal transduction in a range of cellular and in vivo models. Thus, GRK2 phosphorylation of ciliary SMO, and the ensuing PKA-C binding and inactivation, are critical initiating events for the intracellular steps in Hh signaling. More broadly, our study suggests an expanded role for GRKs in enabling direct GPCR interactions with diverse intracellular effectors.
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6
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Luxmi R, King SM. Cilia Provide a Platform for the Generation, Regulated Secretion, and Reception of Peptidergic Signals. Cells 2024; 13:303. [PMID: 38391915 PMCID: PMC10886904 DOI: 10.3390/cells13040303] [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: 01/15/2024] [Revised: 01/31/2024] [Accepted: 02/02/2024] [Indexed: 02/24/2024] Open
Abstract
Cilia are microtubule-based cellular projections that act as motile, sensory, and secretory organelles. These structures receive information from the environment and transmit downstream signals to the cell body. Cilia also release vesicular ectosomes that bud from the ciliary membrane and carry an array of bioactive enzymes and peptide products. Peptidergic signals represent an ancient mode of intercellular communication, and in metazoans are involved in the maintenance of cellular homeostasis and various other physiological processes and responses. Numerous peptide receptors, subtilisin-like proteases, the peptide-amidating enzyme, and bioactive amidated peptide products have been localized to these organelles. In this review, we detail how cilia serve as specialized signaling organelles and act as a platform for the regulated processing and secretion of peptidergic signals. We especially focus on the processing and trafficking pathways by which a peptide precursor from the green alga Chlamydomonas reinhardtii is converted into an amidated bioactive product-a chemotactic modulator-and released from cilia in ectosomes. Biochemical dissection of this complex ciliary secretory pathway provides a paradigm for understanding cilia-based peptidergic signaling in mammals and other eukaryotes.
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Affiliation(s)
| | - Stephen M. King
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030-3305, USA;
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7
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Hoffmann F, Bolz S, Junger K, Klose F, Stehle IF, Ueffing M, Boldt K, Beyer T. Paralog-specific TTC30 regulation of Sonic hedgehog signaling. Front Mol Biosci 2023; 10:1268722. [PMID: 38074101 PMCID: PMC10701685 DOI: 10.3389/fmolb.2023.1268722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 11/09/2023] [Indexed: 02/12/2024] Open
Abstract
The intraflagellar transport (IFT) machinery is essential for cilia assembly, maintenance, and trans-localization of signaling proteins. The IFT machinery consists of two large multiprotein complexes, one of which is the IFT-B. TTC30A and TTC30B are integral components of this complex and were previously shown to have redundant functions in the context of IFT, preventing the disruption of IFT-B and, thus, having a severe ciliogenesis defect upon loss of one paralog. In this study, we re-analyzed the paralog-specific protein complexes and discovered a potential involvement of TTC30A or TTC30B in ciliary signaling. Specifically, we investigated a TTC30A-specific interaction with protein kinase A catalytic subunit α, a negative regulator of Sonic hedgehog (Shh) signaling. Defects in this ciliary signaling pathway are often correlated to synpolydactyly, which, intriguingly, is also linked to a rare TTC30 variant. For an in-depth analysis of this unique interaction and the influence on Shh, TTC30A or B single- and double-knockout hTERT-RPE1 were employed, as well as rescue cells harboring wildtype TTC30 or the corresponding mutation. We could show that mutant TTC30A inhibits the ciliary localization of Smoothened. This observed effect is independent of Patched1 but associated with a distinct phosphorylated PKA substrate accumulation upon treatment with forskolin. This rather prominent phenotype was attenuated in mutant TTC30B. Mass spectrometry analysis of wildtype versus mutated TTC30A or TTC30B uncovered differences in protein complex patterns and identified an impaired TTC30A-IFT57 interaction as the possible link leading to synpolydactyly. We could observe no impact on cilia assembly, leading to the hypothesis that a slight decrease in IFT-B binding can be compensated, but mild phenotypes, like synpolydactyly, can be induced by subtle signaling changes. Our systematic approach revealed the paralog-specific influence of TTC30A KO and mutated TTC30A on the activity of PRKACA and the uptake of Smoothened into the cilium, resulting in a downregulation of Shh. This downregulation, combined with interactome alterations, suggests a potential mechanism of how mutant TTC30A is linked to synpolydactyly.
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Affiliation(s)
- Felix Hoffmann
- Institute for Ophthalmic Research, Eberhard Karls University Tübingen, Tübingen, Germany
| | | | | | | | | | | | | | - Tina Beyer
- *Correspondence: Felix Hoffmann, ; Tina Beyer,
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8
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Gopalakrishnan J, Feistel K, Friedrich BM, Grapin‐Botton A, Jurisch‐Yaksi N, Mass E, Mick DU, Müller R, May‐Simera H, Schermer B, Schmidts M, Walentek P, Wachten D. Emerging principles of primary cilia dynamics in controlling tissue organization and function. EMBO J 2023; 42:e113891. [PMID: 37743763 PMCID: PMC10620770 DOI: 10.15252/embj.2023113891] [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: 02/27/2023] [Revised: 08/07/2023] [Accepted: 09/08/2023] [Indexed: 09/26/2023] Open
Abstract
Primary cilia project from the surface of most vertebrate cells and are key in sensing extracellular signals and locally transducing this information into a cellular response. Recent findings show that primary cilia are not merely static organelles with a distinct lipid and protein composition. Instead, the function of primary cilia relies on the dynamic composition of molecules within the cilium, the context-dependent sensing and processing of extracellular stimuli, and cycles of assembly and disassembly in a cell- and tissue-specific manner. Thereby, primary cilia dynamically integrate different cellular inputs and control cell fate and function during tissue development. Here, we review the recently emerging concept of primary cilia dynamics in tissue development, organization, remodeling, and function.
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Affiliation(s)
- Jay Gopalakrishnan
- Institute for Human Genetics, Heinrich‐Heine‐UniversitätUniversitätsklinikum DüsseldorfDüsseldorfGermany
| | - Kerstin Feistel
- Department of Zoology, Institute of BiologyUniversity of HohenheimStuttgartGermany
| | | | - Anne Grapin‐Botton
- Cluster of Excellence Physics of Life, TU DresdenDresdenGermany
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at The University Hospital Carl Gustav Carus and Faculty of Medicine of the TU DresdenDresdenGermany
| | - Nathalie Jurisch‐Yaksi
- Department of Clinical and Molecular MedicineNorwegian University of Science and TechnologyTrondheimNorway
| | - Elvira Mass
- Life and Medical Sciences Institute, Developmental Biology of the Immune SystemUniversity of BonnBonnGermany
| | - David U Mick
- Center for Molecular Signaling (PZMS), Center of Human and Molecular Biology (ZHMB)Saarland School of MedicineHomburgGermany
| | - Roman‐Ulrich Müller
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD), Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | - Helen May‐Simera
- Institute of Molecular PhysiologyJohannes Gutenberg‐UniversityMainzGermany
| | - Bernhard Schermer
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD), Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | - Miriam Schmidts
- Pediatric Genetics Division, Center for Pediatrics and Adolescent MedicineUniversity Hospital FreiburgFreiburgGermany
- CIBSS‐Centre for Integrative Biological Signalling StudiesUniversity of FreiburgFreiburgGermany
| | - Peter Walentek
- CIBSS‐Centre for Integrative Biological Signalling StudiesUniversity of FreiburgFreiburgGermany
- Renal Division, Internal Medicine IV, Medical CenterUniversity of FreiburgFreiburgGermany
| | - Dagmar Wachten
- Institute of Innate Immunity, Biophysical Imaging, Medical FacultyUniversity of BonnBonnGermany
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Shi P, Tian J, Mallinger JC, Ling D, Deleyrolle LP, McIntyre JC, Caspary T, Breunig JJ, Sarkisian MR. Increasing Ciliary ARL13B Expression Drives Active and Inhibitor-Resistant Smoothened and GLI into Glioma Primary Cilia. Cells 2023; 12:2354. [PMID: 37830570 PMCID: PMC10571910 DOI: 10.3390/cells12192354] [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: 07/19/2023] [Revised: 09/14/2023] [Accepted: 09/20/2023] [Indexed: 10/14/2023] Open
Abstract
ADP-ribosylation factor-like protein 13B (ARL13B), a regulatory GTPase and guanine exchange factor (GEF), enriches in primary cilia and promotes tumorigenesis in part by regulating Smoothened (SMO), GLI, and Sonic Hedgehog (SHH) signaling. Gliomas with increased ARL13B, SMO, and GLI2 expression are more aggressive, but the relationship to cilia is unclear. Previous studies have showed that increasing ARL13B in glioblastoma cells promoted ciliary SMO accumulation, independent of exogenous SHH addition. Here, we show that SMO accumulation is due to increased ciliary, but not extraciliary, ARL13B. Increasing ARL13B expression promotes the accumulation of both activated SMO and GLI2 in glioma cilia. ARL13B-driven increases in ciliary SMO and GLI2 are resistant to SMO inhibitors, GDC-0449, and cyclopamine. Surprisingly, ARL13B-induced changes in ciliary SMO/GLI2 did not correlate with canonical changes in downstream SHH pathway genes. However, glioma cell lines whose cilia overexpress WT but not guanine exchange factor-deficient ARL13B, display reduced INPP5e, a ciliary membrane component whose depletion may favor SMO/GLI2 enrichment. Glioma cells overexpressing ARL13B also display reduced ciliary intraflagellar transport 88 (IFT88), suggesting that altered retrograde transport could further promote SMO/GLI accumulation. Collectively, our data suggest that factors increasing ARL13B expression in glioma cells may promote both changes in ciliary membrane characteristics and IFT proteins, leading to the accumulation of drug-resistant SMO and GLI. The downstream targets and consequences of these ciliary changes require further investigation.
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Affiliation(s)
- Ping Shi
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL 32610, USA; (P.S.); (J.T.); (J.C.M.); (D.L.); (J.C.M.)
| | - Jia Tian
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL 32610, USA; (P.S.); (J.T.); (J.C.M.); (D.L.); (J.C.M.)
| | - Julianne C. Mallinger
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL 32610, USA; (P.S.); (J.T.); (J.C.M.); (D.L.); (J.C.M.)
| | - Dahao Ling
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL 32610, USA; (P.S.); (J.T.); (J.C.M.); (D.L.); (J.C.M.)
| | - Loic P. Deleyrolle
- Preston A. Wells Jr. Center for Brain Tumor Therapy, University of Florida College of Medicine, Gainesville, FL 32610, USA;
- Department of Neurosurgery, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Jeremy C. McIntyre
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL 32610, USA; (P.S.); (J.T.); (J.C.M.); (D.L.); (J.C.M.)
| | - Tamara Caspary
- Department of Human Genetics, Emory School of Medicine, Atlanta, GA 30322, USA;
| | - Joshua J. Breunig
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA;
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Matthew R. Sarkisian
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL 32610, USA; (P.S.); (J.T.); (J.C.M.); (D.L.); (J.C.M.)
- Preston A. Wells Jr. Center for Brain Tumor Therapy, University of Florida College of Medicine, Gainesville, FL 32610, USA;
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10
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Tian X, Zhao H, Zhou J. Organization, functions, and mechanisms of the BBSome in development, ciliopathies, and beyond. eLife 2023; 12:e87623. [PMID: 37466224 DOI: 10.7554/elife.87623] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 07/06/2023] [Indexed: 07/20/2023] Open
Abstract
The BBSome is an octameric protein complex that regulates ciliary transport and signaling. Mutations in BBSome subunits are closely associated with ciliary defects and lead to ciliopathies, notably Bardet-Biedl syndrome. Over the past few years, there has been significant progress in elucidating the molecular organization and functions of the BBSome complex. An improved understanding of BBSome-mediated biological events and molecular mechanisms is expected to help advance the development of diagnostic and therapeutic approaches for BBSome-related diseases. Here, we review the current literature on the structural assembly, transport regulation, and molecular functions of the BBSome, emphasizing its roles in cilium-related processes. We also provide perspectives on the pathological role of the BBSome in ciliopathies as well as how these can be exploited for therapeutic benefit.
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Affiliation(s)
- Xiaoyu Tian
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Huijie Zhao
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Jun Zhou
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
- State Key Laboratory of Medicinal Chemical Biology, Haihe Laboratory of Cell Ecosystem, College of Life Sciences, Nankai University, Tianjin, China
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11
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Mill P, Christensen ST, Pedersen LB. Primary cilia as dynamic and diverse signalling hubs in development and disease. Nat Rev Genet 2023; 24:421-441. [PMID: 37072495 PMCID: PMC7615029 DOI: 10.1038/s41576-023-00587-9] [Citation(s) in RCA: 61] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2023] [Indexed: 04/20/2023]
Abstract
Primary cilia, antenna-like sensory organelles protruding from the surface of most vertebrate cell types, are essential for regulating signalling pathways during development and adult homeostasis. Mutations in genes affecting cilia cause an overlapping spectrum of >30 human diseases and syndromes, the ciliopathies. Given the immense structural and functional diversity of the mammalian cilia repertoire, there is a growing disconnect between patient genotype and associated phenotypes, with variable severity and expressivity characteristic of the ciliopathies as a group. Recent technological developments are rapidly advancing our understanding of the complex mechanisms that control biogenesis and function of primary cilia across a range of cell types and are starting to tackle this diversity. Here, we examine the structural and functional diversity of primary cilia, their dynamic regulation in different cellular and developmental contexts and their disruption in disease.
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Affiliation(s)
- Pleasantine Mill
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, Scotland
| | | | - Lotte B Pedersen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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12
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Shinde SR, Mick DU, Aoki E, Rodrigues RB, Gygi SP, Nachury MV. The ancestral ESCRT protein TOM1L2 selects ubiquitinated cargoes for retrieval from cilia. Dev Cell 2023; 58:677-693.e9. [PMID: 37019113 PMCID: PMC10133032 DOI: 10.1016/j.devcel.2023.03.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/19/2022] [Accepted: 03/07/2023] [Indexed: 04/07/2023]
Abstract
Many G protein-coupled receptors (GPCRs) reside within cilia of mammalian cells and must undergo regulated exit from cilia for the appropriate transduction of signals such as hedgehog morphogens. Lysine 63-linked ubiquitin (UbK63) chains mark GPCRs for regulated removal from cilia, but the molecular basis of UbK63 recognition inside cilia remains elusive. Here, we show that the BBSome-the trafficking complex in charge of retrieving GPCRs from cilia-engages the ancestral endosomal sorting factor target of Myb1-like 2 (TOM1L2) to recognize UbK63 chains within cilia of human and mouse cells. TOM1L2 directly binds to UbK63 chains and the BBSome, and targeted disruption of the TOM1L2/BBSome interaction results in the accumulation of TOM1L2, ubiquitin, and the GPCRs SSTR3, Smoothened, and GPR161 inside cilia. Furthermore, the single-cell alga Chlamydomonas also requires its TOM1L2 ortholog in order to clear ubiquitinated proteins from cilia. We conclude that TOM1L2 broadly enables the retrieval of UbK63-tagged proteins by the ciliary trafficking machinery.
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Affiliation(s)
- Swapnil Rohidas Shinde
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - David U Mick
- Center of Human and Molecular Biology and Center for Molecular Signaling, Department of Medical Biochemistry and Molecular Biology, Saarland University School of Medicine, Homburg, Germany
| | - Erika Aoki
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Rachel B Rodrigues
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Maxence V Nachury
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, USA.
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13
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Chiuso F, Delle Donne R, Giamundo G, Rinaldi L, Borzacchiello D, Moraca F, Intartaglia D, Iannucci R, Senatore E, Lignitto L, Garbi C, Conflitti P, Catalanotti B, Conte I, Feliciello A. Ubiquitylation of BBSome is required for ciliary assembly and signaling. EMBO Rep 2023; 24:e55571. [PMID: 36744302 PMCID: PMC10074118 DOI: 10.15252/embr.202255571] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 12/27/2022] [Accepted: 01/17/2023] [Indexed: 02/07/2023] Open
Abstract
Bardet-Biedl syndrome (BBS) is a ciliopathy characterized by retinal degeneration, obesity, renal abnormalities, postaxial polydactyly, and developmental defects. Genes mutated in BBS encode for components and regulators of the BBSome, an octameric complex that controls the trafficking of cargos and receptors within the primary cilium. Although both structure and function of the BBSome have been extensively studied, the impact of ubiquitin signaling on BBSome is largely unknown. We identify the E3 ubiquitin ligase PJA2 as a novel resident of the ciliary compartment and regulator of the BBSome. Upon GPCR-cAMP stimulation, PJA2 ubiquitylates BBSome subunits. We demonstrate that ubiquitylation of BBS1 at lysine 143 increases the stability of the BBSome and promotes its binding to BBS3, an Arf-like GTPase protein controlling the targeting of the BBSome to the ciliary membrane. Downregulation of PJA2 or expression of a ubiquitylation-defective BBS1 mutant (BBS1K143R ) affects the trafficking of G-protein-coupled receptors (GPCRs) and Shh-dependent gene transcription. Expression of BBS1K143R in vivo impairs cilium formation, embryonic development, and photoreceptors' morphogenesis, thus recapitulating the BBS phenotype in the medaka fish model.
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Affiliation(s)
- Francesco Chiuso
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
| | - Rossella Delle Donne
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
| | - Giuliana Giamundo
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy.,Department of Biology, University of Naples Federico II, Naples, Italy
| | - Laura Rinaldi
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
| | - Domenica Borzacchiello
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
| | - Federica Moraca
- Department of Pharmacy, University of Naples "Federico II", Naples, Italy.,Net4Science srl, University "Magna Graecia" of Catanzaro, Catanzaro, Italy
| | | | - Rosa Iannucci
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
| | - Emanuela Senatore
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
| | - Luca Lignitto
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy.,Cancer Research Center of Marseille (CRCM), CNRS, Aix Marseille Univ, INSERM, Institut Paoli-Calmettes, Marseille, France
| | - Corrado Garbi
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
| | - Paolo Conflitti
- Faculty of Biomedical Sciences, Institute of Computational Science, Università della Svizzera Italiana (USI), Lugano, Switzerland
| | - Bruno Catalanotti
- Department of Pharmacy, University of Naples "Federico II", Naples, Italy
| | - Ivan Conte
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy.,Department of Biology, University of Naples Federico II, Naples, Italy
| | - Antonio Feliciello
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
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14
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Aslanyan MG, Doornbos C, Diwan GD, Anvarian Z, Beyer T, Junger K, van Beersum SEC, Russell RB, Ueffing M, Ludwig A, Boldt K, Pedersen LB, Roepman R. A targeted multi-proteomics approach generates a blueprint of the ciliary ubiquitinome. Front Cell Dev Biol 2023; 11:1113656. [PMID: 36776558 PMCID: PMC9908615 DOI: 10.3389/fcell.2023.1113656] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 01/17/2023] [Indexed: 01/27/2023] Open
Abstract
Establishment and maintenance of the primary cilium as a signaling-competent organelle requires a high degree of fine tuning, which is at least in part achieved by a variety of post-translational modifications. One such modification is ubiquitination. The small and highly conserved ubiquitin protein possesses a unique versatility in regulating protein function via its ability to build mono and polyubiquitin chains onto target proteins. We aimed to take an unbiased approach to generate a comprehensive blueprint of the ciliary ubiquitinome by deploying a multi-proteomics approach using both ciliary-targeted ubiquitin affinity proteomics, as well as ubiquitin-binding domain-based proximity labelling in two different mammalian cell lines. This resulted in the identification of several key proteins involved in signaling, cytoskeletal remodeling and membrane and protein trafficking. Interestingly, using two different approaches in IMCD3 and RPE1 cells, respectively, we uncovered several novel mechanisms that regulate cilia function. In our IMCD3 proximity labeling cell line model, we found a highly enriched group of ESCRT-dependent clathrin-mediated endocytosis-related proteins, suggesting an important and novel role for this pathway in the regulation of ciliary homeostasis and function. In contrast, in RPE1 cells we found that several structural components of caveolae (CAV1, CAVIN1, and EHD2) were highly enriched in our cilia affinity proteomics screen. Consistently, the presence of caveolae at the ciliary pocket and ubiquitination of CAV1 specifically, were found likely to play a role in the regulation of ciliary length in these cells. Cilia length measurements demonstrated increased ciliary length in RPE1 cells stably expressing a ubiquitination impaired CAV1 mutant protein. Furthermore, live cell imaging in the same cells revealed decreased CAV1 protein turnover at the cilium as the possible cause for this phenotype. In conclusion, we have generated a comprehensive list of cilia-specific proteins that are subject to regulation via ubiquitination which can serve to further our understanding of cilia biology in health and disease.
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Affiliation(s)
- Mariam G. Aslanyan
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Cenna Doornbos
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Gaurav D. Diwan
- BioQuant, Heidelberg University, Heidelberg, Germany,Biochemistry Center (BZH), Heidelberg University, Heidelberg, Germany
| | - Zeinab Anvarian
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Tina Beyer
- Institute for Ophthalmic Research, Eberhard Karl University of Tübingen, Tübingen, Germany
| | - Katrin Junger
- Institute for Ophthalmic Research, Eberhard Karl University of Tübingen, Tübingen, Germany
| | - Sylvia E. C. van Beersum
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Robert B. Russell
- BioQuant, Heidelberg University, Heidelberg, Germany,Biochemistry Center (BZH), Heidelberg University, Heidelberg, Germany
| | - Marius Ueffing
- Institute for Ophthalmic Research, Eberhard Karl University of Tübingen, Tübingen, Germany
| | - Alexander Ludwig
- School of Biological Sciences, NTU Institute of Structural Biology, Nanyang Technological University, Singapore City, Singapore
| | - Karsten Boldt
- Institute for Ophthalmic Research, Eberhard Karl University of Tübingen, Tübingen, Germany
| | - Lotte B. Pedersen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Ronald Roepman
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands,*Correspondence: Ronald Roepman,
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15
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Petriman NA, Loureiro-López M, Taschner M, Zacharia NK, Georgieva MM, Boegholm N, Wang J, Mourão A, Russell RB, Andersen JS, Lorentzen E. Biochemically validated structural model of the 15-subunit intraflagellar transport complex IFT-B. EMBO J 2022; 41:e112440. [PMID: 36354106 PMCID: PMC9753473 DOI: 10.15252/embj.2022112440] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/17/2022] [Accepted: 10/20/2022] [Indexed: 11/11/2022] Open
Abstract
Cilia are ubiquitous eukaryotic organelles impotant for cellular motility, signaling, and sensory reception. Cilium formation requires intraflagellar transport of structural and signaling components and involves 22 different proteins organized into intraflagellar transport (IFT) complexes IFT-A and IFT-B that are transported by molecular motors. The IFT-B complex constitutes the backbone of polymeric IFT trains carrying cargo between the cilium and the cell body. Currently, high-resolution structures are only available for smaller IFT-B subcomplexes leaving > 50% structurally uncharacterized. Here, we used Alphafold to structurally model the 15-subunit IFT-B complex. The model was validated using cross-linking/mass-spectrometry data on reconstituted IFT-B complexes, X-ray scattering in solution, diffraction from crystals as well as site-directed mutagenesis and protein-binding assays. The IFT-B structure reveals an elongated and highly flexible complex consistent with cryo-electron tomographic reconstructions of IFT trains. The IFT-B complex organizes into IFT-B1 and IFT-B2 parts with binding sites for ciliary cargo and the inactive IFT dynein motor, respectively. Interestingly, our results are consistent with two different binding sites for IFT81/74 on IFT88/70/52/46 suggesting the possibility of different structural architectures for the IFT-B1 complex. Our data present a structural framework to understand IFT-B complex assembly, function, and ciliopathy variants.
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Affiliation(s)
- Narcis A Petriman
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | - Marta Loureiro-López
- Department for Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Michael Taschner
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Nevin K Zacharia
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | | | - Niels Boegholm
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | - Jiaolong Wang
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | - André Mourão
- Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany
| | | | - Jens S Andersen
- Department for Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Esben Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
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16
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Abstract
The assembly and maintenance of most cilia and eukaryotic flagella depends on intraflagellar transport (IFT), the bidirectional movement of multi-megadalton IFT trains along the axonemal microtubules. These IFT trains function as carriers, moving ciliary proteins between the cell body and the organelle. Whereas tubulin, the principal protein of cilia, binds directly to IFT particle proteins, the transport of other ciliary proteins and complexes requires adapters that link them to the trains. Large axonemal substructures, such as radial spokes, outer dynein arms and inner dynein arms, assemble in the cell body before attaching to IFT trains, using the adapters ARMC2, ODA16 and IDA3, respectively. Ciliary import of several membrane proteins involves the putative adapter tubby-like protein 3 (TULP3), whereas membrane protein export involves the BBSome, an octameric complex that co-migrates with IFT particles. Thus, cells employ a variety of adapters, each of which is substoichiometric to the core IFT machinery, to expand the cargo range of the IFT trains. This Review summarizes the individual and shared features of the known cargo adapters and discusses their possible role in regulating the transport capacity of the IFT pathway.
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Affiliation(s)
- Karl Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
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17
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Zhou Z, Katoh Y, Nakayama K. CEP19-RABL2-IFT-B axis controls BBSome-mediated ciliary GPCR export. Mol Biol Cell 2022; 33:ar126. [PMID: 36074075 PMCID: PMC9634966 DOI: 10.1091/mbc.e22-05-0161] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The intraflagellar transport (IFT) machinery mediates the import and export of ciliary proteins across the ciliary gate, as well as bidirectional protein trafficking within cilia. In addition to ciliary anterograde protein trafficking, the IFT-B complex participates in the export of membrane proteins together with the BBSome, which consists of eight subunits encoded by the causative genes of Bardet-Biedl syndrome (BBS). The IFT25-IFT27/BBS19 dimer in the IFT-B complex constitutes its interface with the BBSome. We show here that IFT25-IFT27 and the RABL2 GTPase bind the IFT74/BBS22-IFT81 dimer of the IFT-B complex in a mutually exclusive manner. Cells expressing GTP-locked RABL2 [RABL2(Q80L)], but not wild-type RABL2, phenocopied IFT27-knockout cells, that is, they demonstrated BBS-associated ciliary defects, including accumulation of LZTFL1/BBS17 and the BBSome within cilia and the suppression of export of the ciliary GPCRs GPR161 and Smoothened. RABL2(Q80L) enters cilia in a manner dependent on the basal body protein CEP19, but its entry into cilia is not necessary for causing BBS-associated ciliary defects. These observations suggest that GTP-bound RABL2 is likely to be required for recruitment of the IFT-B complex to the ciliary base, where it is replaced with IFT25-IFT27.
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Affiliation(s)
| | - Yohei Katoh
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan,*Address correspondence to: Kazuhisa Nakayama (); Yohei Katoh ()
| | - Kazuhisa Nakayama
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan,*Address correspondence to: Kazuhisa Nakayama (); Yohei Katoh ()
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18
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Nicheperovich A, Townsend-Nicholson A. Towards Precision Oncology: The Role of Smoothened and Its Variants in Cancer. J Pers Med 2022; 12:jpm12101648. [PMID: 36294790 PMCID: PMC9605185 DOI: 10.3390/jpm12101648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 09/28/2022] [Accepted: 09/29/2022] [Indexed: 11/07/2022] Open
Abstract
The G protein-coupled receptor Smoothened (Smo) is a central signal transducer of the Hedgehog (Hh) pathway which has been linked to diverse forms of tumours. Stimulated by advancements in structural and functional characterisation, the Smo receptor has been recognised as an important therapeutic target in Hh-driven cancers, and several Smo inhibitors have now been approved for cancer therapy. This receptor is also known to be an oncoprotein itself and its gain-of-function variants have been associated with skin, brain, and liver cancers. According to the COSMIC database, oncogenic mutations of Smo have been identified in various other tumours, although their oncogenic effect remains unknown in these tissues. Drug resistance is a common challenge in cancer therapies targeting Smo, and data analysis shows that healthy individuals also harbour resistance mutations. Based on the importance of Smo in cancer progression and the high incidence of resistance towards Smo inhibitors, this review suggests that detection of Smo variants through tumour profiling could lead to increased precision and improved outcomes of anti-cancer treatments.
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19
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Abstract
Cilia sense and transduce sensory stimuli, homeostatic cues and developmental signals by orchestrating signaling reactions. Extracellular vesicles (EVs) that bud from the ciliary membrane have well-studied roles in the disposal of excess ciliary material, most dramatically exemplified by the shedding of micrometer-sized blocks by photoreceptors. Shedding of EVs by cilia also affords cells with a powerful means to shorten cilia. Finally, cilium-derived EVs may enable cell-cell communication in a variety of organisms, ranging from single-cell parasites and algae to nematodes and vertebrates. Mechanistic understanding of EV shedding by cilia is an active area of study, and future progress may open the door to testing the function of ciliary EV shedding in physiological contexts. In this Cell Science at a Glance and the accompanying poster, we discuss the molecular mechanisms that drive the shedding of ciliary material into the extracellular space, the consequences of shedding for the donor cell and the possible roles that ciliary EVs may have in cell non-autonomous contexts.
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Affiliation(s)
- Irene Ojeda Naharros
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143-3120, USA
| | - Maxence V. Nachury
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143-3120, USA
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20
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Jiang J. Hedgehog signaling mechanism and role in cancer. Semin Cancer Biol 2022; 85:107-122. [PMID: 33836254 PMCID: PMC8492792 DOI: 10.1016/j.semcancer.2021.04.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 03/25/2021] [Accepted: 04/02/2021] [Indexed: 12/12/2022]
Abstract
Cell-cell communication through evolutionarily conserved signaling pathways governs embryonic development and adult tissue homeostasis. Deregulation of these signaling pathways has been implicated in a wide range of human diseases including cancer. One such pathway is the Hedgehog (Hh) pathway, which was originally discovered in Drosophila and later found to play a fundamental role in human development and diseases. Abnormal Hh pathway activation is a major driver of basal cell carcinomas (BCC) and medulloblastoma. Hh exerts it biological influence through a largely conserved signal transduction pathway from the activation of the GPCR family transmembrane protein Smoothened (Smo) to the conversion of latent Zn-finger transcription factors Gli/Ci proteins from their repressor (GliR/CiR) to activator (GliA/CiA) forms. Studies from model organisms and human patients have provided deep insight into the Hh signal transduction mechanisms, revealed roles of Hh signaling in a wide range of human cancers, and suggested multiple strategies for targeting this pathway in cancer treatment.
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Affiliation(s)
- Jin Jiang
- Department of Molecular Biology and Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, 75390, USA.
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21
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Happ JT, Arveseth CD, Bruystens J, Bertinetti D, Nelson IB, Olivieri C, Zhang J, Hedeen DS, Zhu JF, Capener JL, Bröckel JW, Vu L, King CC, Ruiz-Perez VL, Ge X, Veglia G, Herberg FW, Taylor SS, Myers BR. A PKA inhibitor motif within SMOOTHENED controls Hedgehog signal transduction. Nat Struct Mol Biol 2022; 29:990-999. [PMID: 36202993 PMCID: PMC9696579 DOI: 10.1038/s41594-022-00838-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 08/22/2022] [Indexed: 02/03/2023]
Abstract
The Hedgehog (Hh) cascade is central to development, tissue homeostasis and cancer. A pivotal step in Hh signal transduction is the activation of glioma-associated (GLI) transcription factors by the atypical G protein-coupled receptor (GPCR) SMOOTHENED (SMO). How SMO activates GLI remains unclear. Here we show that SMO uses a decoy substrate sequence to physically block the active site of the cAMP-dependent protein kinase (PKA) catalytic subunit (PKA-C) and extinguish its enzymatic activity. As a result, GLI is released from phosphorylation-induced inhibition. Using a combination of in vitro, cellular and organismal models, we demonstrate that interfering with SMO-PKA pseudosubstrate interactions prevents Hh signal transduction. The mechanism uncovered echoes one used by the Wnt cascade, revealing an unexpected similarity in how these two essential developmental and cancer pathways signal intracellularly. More broadly, our findings define a mode of GPCR-PKA communication that may be harnessed by a range of membrane receptors and kinases.
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Affiliation(s)
- John T Happ
- Department of Oncological Sciences, Department of Biochemistry, and Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Corvin D Arveseth
- Department of Oncological Sciences, Department of Biochemistry, and Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, UT, USA
- Washington University School of Medicine, St. Louis, MO, USA
| | - Jessica Bruystens
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Daniela Bertinetti
- Institute for Biology, Department of Biochemistry, University of Kassel, Kassel, Germany
| | - Isaac B Nelson
- Department of Oncological Sciences, Department of Biochemistry, and Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Cristina Olivieri
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Jingyi Zhang
- Department of Molecular and Cell Biology, School of Natural Sciences, University of California, Merced, CA, USA
| | - Danielle S Hedeen
- Department of Oncological Sciences, Department of Biochemistry, and Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Ju-Fen Zhu
- Department of Oncological Sciences, Department of Biochemistry, and Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Jacob L Capener
- Department of Oncological Sciences, Department of Biochemistry, and Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, UT, USA
- Biological and Biomedical Sciences Program, University of North Carolina, Chapel Hill, NC, USA
| | - Jan W Bröckel
- Institute for Biology, Department of Biochemistry, University of Kassel, Kassel, Germany
| | - Lily Vu
- Department of Neurobiology, University of California, San Diego, La Jolla, CA, USA
| | - C C King
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Victor L Ruiz-Perez
- Instituto de Investigaciones Biomédicas 'Alberto Sols,' Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid, Madrid, Spain
- CIBER de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Xuecai Ge
- Department of Molecular and Cell Biology, School of Natural Sciences, University of California, Merced, CA, USA
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Friedrich W Herberg
- Institute for Biology, Department of Biochemistry, University of Kassel, Kassel, Germany
| | - Susan S Taylor
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA.
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA.
| | - Benjamin R Myers
- Department of Oncological Sciences, Department of Biochemistry, and Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, UT, USA.
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22
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Dai J, Zhang G, Alkhofash RA, Mekonnen B, Saravanan S, Xue B, Fan ZC, Betleja E, Cole DG, Liu P, Lechtreck K. Loss of ARL13 impedes BBSome-dependent cargo export from Chlamydomonas cilia. J Cell Biol 2022; 221:213429. [PMID: 36040375 PMCID: PMC9436004 DOI: 10.1083/jcb.202201050] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 05/12/2022] [Accepted: 07/11/2022] [Indexed: 12/25/2022] Open
Abstract
The GTPase Arl13b participates in ciliary protein transport, but its contribution to intraflagellar transport (IFT), the main motor-based protein shuttle of cilia, remains largely unknown. Chlamydomonas arl13 mutant cilia were characterized by both abnormal reduction and accumulation of select membrane-associated proteins. With respect to the latter, a similar set of proteins including phospholipase D (PLD) also accumulated in BBSome-deficient cilia. IFT and BBSome traffic were apparently normal in arl13. However, transport of PLD, which in control cells moves by BBSome-dependent IFT, was impaired in arl13, causing PLD to accumulate in cilia. ARL13 only rarely and transiently traveled by IFT, indicating that it is not a co-migrating adapter securing PLD to IFT trains. In conclusion, the loss of Chlamydomonas ARL13 impedes BBSome-dependent protein transport, resulting in overlapping biochemical defects in arl13 and bbs mutant cilia.
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Affiliation(s)
- Jin Dai
- Cellular Biology, University of Georgia, Athens, GA
| | - Gui Zhang
- Cellular Biology, University of Georgia, Athens, GA
| | | | | | | | - Bin Xue
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Zhen-Chuan Fan
- State Key Laboratory of Food Nutrition and Safety, Institute of Health Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | | | | | - Peiwei Liu
- College of Life Science, Shandong Normal University, Jinan, Shandong, China
| | - Karl Lechtreck
- Cellular Biology, University of Georgia, Athens, GA,Correspondence to Karl F. Lechtreck:
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23
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Lv B, Zhang XO, Pazour GJ. Arih2 regulates Hedgehog signaling through smoothened ubiquitylation and ER-associated degradation. J Cell Sci 2022; 135:jcs260299. [PMID: 35899529 PMCID: PMC9481925 DOI: 10.1242/jcs.260299] [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: 06/01/2022] [Accepted: 07/18/2022] [Indexed: 11/20/2022] Open
Abstract
During Hedgehog signaling, the ciliary levels of Ptch1 and Smo are regulated by the pathway. At the basal state, Ptch1 localizes to cilia and prevents the ciliary accumulation and activation of Smo. Upon binding a Hedgehog ligand, Ptch1 exits cilia, relieving inhibition of Smo. Smo then concentrates in cilia, becomes activated and activates downstream signaling. Loss of the ubiquitin E3 ligase Arih2 elevates basal Hedgehog signaling, elevates the cellular level of Smo and increases basal levels of ciliary Smo. Mice express two isoforms of Arih2 with Arih2α found primarily in the nucleus and Arih2β found on the cytoplasmic face of the endoplasmic reticulum (ER). Re-expression of ER-localized Arih2β but not nuclear-localized Arih2α rescues the Arih2 mutant phenotypes. When Arih2 is defective, protein aggregates accumulate in the ER and the unfolded protein response is activated. Arih2β appears to regulate the ER-associated degradation (ERAD) of Smo preventing excess and potentially misfolded Smo from reaching the cilium and interfering with pathway regulation.
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Affiliation(s)
- Bo Lv
- Program in Molecular Medicine, University of Massachusetts Medical School, Biotech II, Suite 213, 373 Plantation Street, Worcester, MA 01605, USA
| | - Xiao-Ou Zhang
- Shanghai Key Laboratory of Maternal and Fetal Medicine, Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China200092
| | - Gregory J. Pazour
- Program in Molecular Medicine, University of Massachusetts Medical School, Biotech II, Suite 213, 373 Plantation Street, Worcester, MA 01605, USA
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24
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Schembs L, Willems A, Hasenpusch-Theil K, Cooper JD, Whiting K, Burr K, Bøstrand SMK, Selvaraj BT, Chandran S, Theil T. The ciliary gene INPP5E confers dorsal telencephalic identity to human cortical organoids by negatively regulating Sonic hedgehog signaling. Cell Rep 2022; 39:110811. [PMID: 35584663 PMCID: PMC9620745 DOI: 10.1016/j.celrep.2022.110811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 02/07/2022] [Accepted: 04/20/2022] [Indexed: 12/02/2022] Open
Abstract
Defects in primary cilia, cellular antennas that control multiple intracellular signaling pathways, underlie several neurodevelopmental disorders, but it remains unknown how cilia control essential steps in human brain formation. Here, we show that cilia are present on the apical surface of radial glial cells in human fetal forebrain. Interfering with cilia signaling in human organoids by mutating the INPP5E gene leads to the formation of ventral telencephalic cell types instead of cortical progenitors and neurons. INPP5E mutant organoids also show increased Sonic hedgehog (SHH) signaling, and cyclopamine treatment partially rescues this ventralization. In addition, ciliary expression of SMO, GLI2, GPR161, and several intraflagellar transport (IFT) proteins is increased. Overall, these findings establish the importance of primary cilia for dorsal and ventral patterning in human corticogenesis, indicate a tissue-specific role of INPP5E as a negative regulator of SHH signaling, and have implications for the emerging roles of cilia in the pathogenesis of neurodevelopmental disorders.
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Affiliation(s)
- Leah Schembs
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Ariane Willems
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK; UK Dementia Research Institute at University of Edinburgh, University of Edinburgh, Edinburgh EH16 4SB, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, Edinburgh EH8 9XD, UK
| | - Kerstin Hasenpusch-Theil
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, Edinburgh EH8 9XD, UK
| | - James D Cooper
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK; UK Dementia Research Institute at University of Edinburgh, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Katie Whiting
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Karen Burr
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK; UK Dementia Research Institute at University of Edinburgh, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Sunniva M K Bøstrand
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Bhuvaneish T Selvaraj
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK; UK Dementia Research Institute at University of Edinburgh, University of Edinburgh, Edinburgh EH16 4SB, UK; Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Siddharthan Chandran
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK; UK Dementia Research Institute at University of Edinburgh, University of Edinburgh, Edinburgh EH16 4SB, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, Edinburgh EH8 9XD, UK; Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Thomas Theil
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, Edinburgh EH8 9XD, UK.
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25
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Senatore E, Iannucci R, Chiuso F, Delle Donne R, Rinaldi L, Feliciello A. Pathophysiology of Primary Cilia: Signaling and Proteostasis Regulation. Front Cell Dev Biol 2022; 10:833086. [PMID: 35646931 PMCID: PMC9130585 DOI: 10.3389/fcell.2022.833086] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 04/21/2022] [Indexed: 01/29/2023] Open
Abstract
Primary cilia are microtubule-based, non-motile sensory organelles present in most types of growth-arrested eukaryotic cells. They are transduction hubs that receive and transmit external signals to the cells in order to control growth, differentiation and development. Mutations of genes involved in the formation, maintenance or disassembly of ciliary structures cause a wide array of developmental genetic disorders, also known as ciliopathies. The primary cilium is formed during G1 in the cell cycle and disassembles at the G2/M transition. Following the completion of the cell division, the cilium reassembles in G1. This cycle is finely regulated at multiple levels. The ubiquitin-proteasome system (UPS) and the autophagy machinery, two main protein degradative systems in cells, play a fundamental role in cilium dynamics. Evidence indicate that UPS, autophagy and signaling pathways may act in synergy to control the ciliary homeostasis. However, the mechanisms involved and the links between these regulatory systems and cilium biogenesis, dynamics and signaling are not well defined yet. Here, we discuss the reciprocal regulation of signaling pathways and proteolytic machineries in the control of the assembly and disassembly of the primary cilium, and the impact of the derangement of these regulatory networks in human ciliopathies.
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26
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Lechtreck KF, Liu Y, Dai J, Alkhofash RA, Butler J, Alford L, Yang P. Chlamydomonas ARMC2/PF27 is an obligate cargo adapter for intraflagellar transport of radial spokes. eLife 2022; 11:74993. [PMID: 34982025 PMCID: PMC8789290 DOI: 10.7554/elife.74993] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 01/03/2022] [Indexed: 12/19/2022] Open
Abstract
Intraflagellar transport (IFT) carries proteins into flagella but how IFT trains interact with the large number of diverse proteins required to assemble flagella remains largely unknown. Here, we show that IFT of radial spokes in Chlamydomonas requires ARMC2/PF27, a conserved armadillo repeat protein associated with male infertility and reduced lung function. Chlamydomonas ARMC2 was highly enriched in growing flagella and tagged ARMC2 and the spoke protein RSP3 co-migrated on anterograde trains. In contrast, a cargo and an adapter of inner and outer dynein arms moved independently of ARMC2, indicating that unrelated cargoes distribute stochastically onto the IFT trains. After concomitant unloading at the flagellar tip, RSP3 attached to the axoneme whereas ARMC2 diffused back to the cell body. In armc2/pf27 mutants, IFT of radial spokes was abolished and the presence of radial spokes was limited to the proximal region of flagella. We conclude that ARMC2 is a cargo adapter required for IFT of radial spokes to ensure their assembly along flagella. ARMC2 belongs to a growing class of cargo-specific adapters that enable flagellar transport of preassembled axonemal substructures by IFT.
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Affiliation(s)
- Karl F Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, United States
| | - Yi Liu
- Department of Biological Sciences, Marquette University, Milwaukee, United States
| | - Jin Dai
- Department of Cellular Biology, University of Georgia, Athens, United States
| | - Rama A Alkhofash
- Department of Cellular Biology, University of Georgia, Athens, United States
| | - Jack Butler
- Department of Cellular Biology, University of Georgia, Athens, United States
| | - Lea Alford
- Division of Natural Sciences,, Oglethorpe University, Atlanta, United States
| | - Pinfen Yang
- Department of Biological Sciences, Marquette University, Milwaukee, United States
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27
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Jia J, Jiang J. Regulation of Smoothened Trafficking and Abundance in Hedgehog Signaling. Front Cell Dev Biol 2022; 10:847844. [PMID: 35321245 PMCID: PMC8936432 DOI: 10.3389/fcell.2022.847844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 02/23/2022] [Indexed: 12/02/2022] Open
Abstract
The GPCR-family protein Smoothened (Smo) is essential for Hedgehog (Hh) signal transduction in both insects and vertebrates. The regulation of subcellular localization and abundance of Smo is a critical step in Hh signaling. Recent studies have demonstrated that Smo is subjected to ubiquitination mediated by multiple E3 ubiquitin ligases, leading to Smo endocytosis and subsequent degradation through the proteasome- and lysosome-mediated pathways in Drosophila. Ubiquitination of Smo also promotes its ciliary exit in mammalian cells. Hh inhibits Smo ubiquitination by blocking E3 ligase recruitment and promoting Smo deubiquitination through the ubiquitin-specific protease 8 (USP8) in Drosophila. Inhibition of Smo ubiquitination by Hh promotes Smo cell surface accumulation in Drosophila and ciliary accumulation in mammalian cells. Interestingly, Hh also induces sumoylation of Smo in both Drosophila and mammalian cells, which promotes Smo cell surface/ciliary accumulation. This review focuses on how ubiquitination and sumoylation regulate Smo intracellular trafficking and abundance and how these processes are regulated by Hh.
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Affiliation(s)
- Jianhang Jia
- Department of Molecular and Cellular Biochemistry, Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Jin Jiang
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, United States
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28
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Abstract
The Hedgehog (Hh) family of secreted proteins governs embryonic development and adult tissue homeostasis by regulating the abundance, localization, and activity of the GPCR family protein Smoothened (Smo). Smo trafficking and subcellular accumulation are controlled by multiple posttranslational modifications (PTMs) including phosphorylation, ubiquitination, and sumoylation, which appears to be conserved from Drosophila to mammals. Smo ubiquitination is dynamically regulated by E3 ubiquitin ligases and deubiquitinases (dubs) and is opposed by Hh signaling. By contrast, Smo sumoylation is stimulated by Hh, which counteracts Smo ubiquitination by recruiting the dub USP8. We describe cell-base assays for Smo ubiquitination and its regulation by Hh and the E3 ligases in Drosophila. We also describe assays for Smo sumoylation in both Drosophila and mammalian cultured cells.
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Affiliation(s)
- Yuhong Han
- Department of Molecular Biology, UT Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - Jin Jiang
- Department of Molecular Biology, UT Southwestern Medical Center at Dallas, Dallas, TX, USA.
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29
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Chandra B, Tung ML, Hsu Y, Scheetz T, Sheffield VC. Retinal ciliopathies through the lens of Bardet-Biedl Syndrome: Past, present and future. Prog Retin Eye Res 2021; 89:101035. [PMID: 34929400 DOI: 10.1016/j.preteyeres.2021.101035] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 12/10/2021] [Accepted: 12/13/2021] [Indexed: 12/15/2022]
Abstract
The primary cilium is a highly specialized and evolutionary conserved organelle in eukaryotes that plays a significant role in cell signaling and trafficking. Over the past few decades tremendous progress has been made in understanding the physiology of cilia and the underlying pathomechanisms of various ciliopathies. Syndromic ciliopathies consist of a group of disorders caused by ciliary dysfunction or abnormal ciliogenesis. These disorders have multiorgan involvement in addition to retinal degeneration underscoring the ubiquitous distribution of primary cilia in different cell types. Genotype-phenotype correlation is often challenging due to the allelic heterogeneity and pleiotropy of these disorders. In this review, we discuss the clinical and genetic features of syndromic ciliopathies with a focus on Bardet-Biedl syndrome (BBS) as a representative disorder. We discuss the structure and function of primary cilia and their role in retinal photoreceptors. We describe the progress made thus far in understanding the functional and genetic characterization including expression quantitative trait locus (eQTL) analysis of BBS genes. In the future directions section, we discuss the emerging technologies, such as gene therapy, as well as anticipated challenges and their implications in therapeutic development for ciliopathies.
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Affiliation(s)
- Bharatendu Chandra
- Stead Family Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Moon Ley Tung
- Stead Family Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Ying Hsu
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, Iowa City, IA, USA
| | - Todd Scheetz
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, Iowa City, IA, USA
| | - Val C Sheffield
- Stead Family Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, Iowa City, IA, USA.
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30
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Zhang Q, Jiang J. Regulation of Hedgehog Signal Transduction by Ubiquitination and Deubiquitination. Int J Mol Sci 2021; 22:ijms222413338. [PMID: 34948134 PMCID: PMC8703657 DOI: 10.3390/ijms222413338] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/07/2021] [Accepted: 12/09/2021] [Indexed: 12/23/2022] Open
Abstract
The Hedgehog (Hh) family of secreted proteins governs embryonic development and adult tissue homeostasis in species ranging from insects to mammals. Deregulation of Hh pathway activity has been implicated in a wide range of human disorders, including congenital diseases and cancer. Hh exerts its biological influence through a conserved signaling pathway. Binding of Hh to its receptor Patched (Ptc), a twelve-span transmembrane protein, leads to activation of an atypical GPCR family protein and Hh signal transducer Smoothened (Smo), which then signals downstream to activate the latent Cubitus interruptus (Ci)/Gli family of transcription factors. Hh signal transduction is regulated by ubiquitination and deubiquitination at multiple steps along the pathway including regulation of Ptc, Smo and Ci/Gli proteins. Here we review the effect of ubiquitination and deubiquitination on the function of individual Hh pathway components, the E3 ubiquitin ligases and deubiquitinases involved, how ubiquitination and deubiquitination are regulated, and whether the underlying mechanisms are conserved from Drosophila to mammals.
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Affiliation(s)
- Qing Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, School of Medicine, Nanjing University, Nanjing 210061, China
- MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, School of Medicine, Nanjing University, Nanjing 210061, China
- Correspondence: (Q.Z.); (J.J.)
| | - Jin Jiang
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX 75390, USA
- Correspondence: (Q.Z.); (J.J.)
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31
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Zhou Z, Qiu H, Castro-Araya RF, Takei R, Nakayama K, Katoh Y. Impaired cooperation between IFT74/BBS22-IFT81 and IFT25-IFT27/BBS19 causes Bardet-Biedl syndrome. Hum Mol Genet 2021; 31:1681-1693. [PMID: 34888642 DOI: 10.1093/hmg/ddab354] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 11/19/2021] [Accepted: 12/06/2021] [Indexed: 02/03/2023] Open
Abstract
The IFT-B complex mediates ciliary anterograde protein trafficking and membrane protein export together with the BBSome. Bardet-Biedl syndrome (BBS) is caused by mutations in not only all BBSome subunits, but also in some IFT-B subunits, including IFT74/BBS22 and IFT27/BBS19, which form heterodimers with IFT81 and IFT25, respectively. We found that the IFT25-IFT27 dimer bind the C-terminal region of the IFT74-IFT81 dimer, and that the IFT25-IFT27-binding region encompasses the region deleted in the BBS variants of IFT74. In addition, we found that the missense BBS variants of IFT27 are impaired in IFT74-IFT81 binding, and are unable to rescue the BBS-like phenotypes of IFT27-knockout cells. Furthermore, the BBS variants of IFT74 rescued the ciliogenesis defect of IFT74-knockout cells, but the rescued cells demonstrated BBS-like abnormal phenotypes. Taken together, we conclude that the impaired interaction between IFT74-IFT81 and IFT25-IFT27 causes the BBS-associated ciliary defects.
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Affiliation(s)
- Zhuang Zhou
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Hantian Qiu
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Roiner-Francisco Castro-Araya
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Ryota Takei
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Kazuhisa Nakayama
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Yohei Katoh
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
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32
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Liu M, Su Y, Peng J, Zhu AJ. Protein modifications in Hedgehog signaling: Cross talk and feedback regulation confer divergent Hedgehog signaling activity. Bioessays 2021; 43:e2100153. [PMID: 34738654 DOI: 10.1002/bies.202100153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 10/06/2021] [Accepted: 10/12/2021] [Indexed: 12/12/2022]
Abstract
The complexity of the Hedgehog (Hh) signaling cascade has increased over the course of evolution; however, it does not suffice to accommodate the dynamic yet robust requirements of differential Hh signaling activity needed for embryonic development and adult homeostatic maintenance. One solution to solve this dilemma is to apply multiple forms of post-translational modifications (PTMs) to the core Hh signaling components, modulating their abundance, localization, and signaling activity. This review summarizes various forms of protein modifications utilized to regulate Hh signaling, with a special emphasis on crosstalk between different forms of PTMs and their feedback regulation by Hh signaling.
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Affiliation(s)
- Min Liu
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Ying Su
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Jingyu Peng
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, China
| | - Alan Jian Zhu
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
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33
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Qiu ZP, Hu A, Song BL. The 3-beta-hydroxysteroid-Delta(8), Delta(7)-isomerase EBP inhibits cholesterylation of Smoothened. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:159041. [PMID: 34450268 DOI: 10.1016/j.bbalip.2021.159041] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 08/14/2021] [Accepted: 08/19/2021] [Indexed: 12/21/2022]
Abstract
Hedgehog (Hh) pathway plays a central role in vertebrate embryonic development and carcinogenesis. The G-protein coupled receptor-like protein Smoothened (SMO) is one of the major members in Hh pathway. Covalent modification of cholesterol on the 95th asparagine (D95) of human SMO, which is regulated by Hh and PTCH1, is critical for SMO activation. However, it is not known whether SMO cholesterylation is regulated by other proteins. In this study, we identified Emopamil binding protein (EBP, also known as 3-beta-hydroxysteroid-Delta(8),Delta(7)-isomerase) as a SMO-interacting protein. Overexpression of EBP suppressed SMO cholesterylation and Hh pathway activity, whereas genetic disruption of EBP enhanced SMO cholesterylation and the downstream signaling. EBP-mediated inhibition of SMO cholesterylation was independent of its isomerase activity, but dependent on the C-terminus of EBP that was required for SMO binding. The X-linked dominant chondrodysplasia punctate 2 (CDPX2)-associated EBP mutants inhibited SMO cholesterylation too. Together, this study shows that EBP modulates SMO cholesterylation through direct binding and suggests a possible mechanism of CDPX2 pathogenesis.
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Affiliation(s)
- Zhi-Ping Qiu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Ao Hu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Bao-Liang Song
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China.
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34
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Cassioli C, Onnis A, Finetti F, Capitani N, Brunetti J, Compeer EB, Niederlova V, Stepanek O, Dustin ML, Baldari CT. The Bardet-Biedl syndrome complex component BBS1 controls T cell polarity during immune synapse assembly. J Cell Sci 2021; 134:jcs258462. [PMID: 34423835 PMCID: PMC7613584 DOI: 10.1242/jcs.258462] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 07/06/2021] [Indexed: 12/24/2022] Open
Abstract
Components of the intraflagellar transport (IFT) system that regulates the assembly of the primary cilium are co-opted by the non-ciliated T cell to orchestrate polarized endosome recycling and to sustain signaling during immune synapse formation. Here, we investigated the potential role of Bardet-Biedl syndrome 1 protein (BBS1), an essential core component of the BBS complex that cooperates with the IFT system in ciliary protein trafficking, in the assembly of the T cell synapse. We demonstrated that BBS1 allows for centrosome polarization towards the immune synapse. This function is achieved through the clearance of centrosomal F-actin and its positive regulator WASH1 (also known as WASHC1), a process that we demonstrated to be dependent on the proteasome. We show that BBS1 regulates this process by coupling the 19S proteasome regulatory subunit to the microtubule motor dynein for its transport to the centrosome. Our data identify the ciliopathy-related protein BBS1 as a new player in T cell synapse assembly that functions upstream of the IFT system to set the stage for polarized vesicular trafficking and sustained signaling. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Chiara Cassioli
- Department of Life Sciences, University of Siena, Siena, Italy
| | - Anna Onnis
- Department of Life Sciences, University of Siena, Siena, Italy
| | | | - Nagaja Capitani
- Department of Life Sciences, University of Siena, Siena, Italy
| | - Jlenia Brunetti
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Ewoud B Compeer
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
| | - Veronika Niederlova
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Ondrej Stepanek
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Michael L Dustin
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
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Wang J, Nikonorova IA, Silva M, Walsh JD, Tilton PE, Gu A, Akella JS, Barr MM. Sensory cilia act as a specialized venue for regulated extracellular vesicle biogenesis and signaling. Curr Biol 2021; 31:3943-3951.e3. [PMID: 34270950 DOI: 10.1016/j.cub.2021.06.040] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/30/2021] [Accepted: 06/14/2021] [Indexed: 02/07/2023]
Abstract
Ciliary extracellular vesicle (EV) shedding is evolutionarily conserved. In Chlamydomonas and C. elegans, ciliary EVs act as signaling devices.1-3 In cultured mammalian cells, ciliary EVs regulate ciliary disposal but also receptor abundance and signaling, ciliary length, and ciliary membrane dynamics.4-7 Mammalian cilia produce EVs from the tip and along the ciliary membrane.8,9 This study aimed to determine the functional significance of shedding at distinct locations and to explore ciliary EV biogenesis mechanisms. Using Airyscan super-resolution imaging in living C. elegans animals, we find that neuronal sensory cilia shed TRP polycystin-2 channel PKD-2::GFP-carrying EVs from two distinct sites: the ciliary tip and the ciliary base. Ciliary tip shedding requires distal ciliary enrichment of PKD-2 by the myristoylated coiled-coil protein CIL-7. Kinesin-3 KLP-6 and intraflagellar transport (IFT) kinesin-2 motors are also required for ciliary tip EV shedding. A big unanswered question in the EV field is how cells sort EV cargo. Here, we show that two EV cargoes- CIL-7 and PKD-2-localized and trafficked differently along cilia and were sorted to different environmentally released EVs. In response to mating partners, C. elegans males modulate EV cargo composition by increasing the ratio of PKD-2 to CIL-7 EVs. Overall, our study indicates that the cilium and its trafficking machinery act as a specialized venue for regulated EV biogenesis and signaling.
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Affiliation(s)
- Juan Wang
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA.
| | - Inna A Nikonorova
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Malan Silva
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Jonathon D Walsh
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Peter E Tilton
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Amanda Gu
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Jyothi S Akella
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Maureen M Barr
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA.
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Lv B, Stuck MW, Desai PB, Cabrera OA, Pazour GJ. E3 ubiquitin ligase Wwp1 regulates ciliary dynamics of the Hedgehog receptor Smoothened. J Cell Biol 2021; 220:212435. [PMID: 34161574 PMCID: PMC8236919 DOI: 10.1083/jcb.202010177] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 05/01/2021] [Accepted: 06/01/2021] [Indexed: 12/26/2022] Open
Abstract
The Hedgehog pathway, critical to vertebrate development, is organized in primary cilia. Activation of signaling causes the Hedgehog receptor Ptch1 to exit cilia, allowing a second receptor, Smo, to accumulate in cilia and activate the downstream steps of the pathway. Mechanisms regulating the dynamics of these receptors are unknown, but the ubiquitination of Smo regulates its interaction with the intraflagellar transport system to control ciliary levels. A focused screen of ubiquitin-related genes identified nine required for maintaining low ciliary Smo at the basal state. These included cytoplasmic E3s (Arih2, Mgrn1, and Maea), a ciliary localized E3 (Wwp1), a ciliary localized E2 (Ube2l3), a deubiquitinase (Bap1), and three adaptors (Kctd5, Skp1a, and Skp2). The ciliary E3, Wwp1, binds Ptch1 and localizes to cilia at the basal state. Activation of signaling removes both Ptch1 and Wwp1 from cilia, thus providing an elegant mechanism for Ptch1 to regulate ciliary Smo levels.
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Affiliation(s)
- Bo Lv
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Michael W Stuck
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Paurav B Desai
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Oscar A Cabrera
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Gregory J Pazour
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA
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Abstract
The intraflagellar transport (IFT) system is a remarkable molecular machine used by cells to assemble and maintain the cilium, a long organelle extending from eukaryotic cells that gives rise to motility, sensing and signaling. IFT plays a critical role in building the cilium by shuttling structural components and signaling receptors between the ciliary base and tip. To provide effective transport, IFT-A and IFT-B adaptor protein complexes assemble into highly repetitive polymers, called IFT trains, that are powered by the motors kinesin-2 and IFT-dynein to move bidirectionally along the microtubules. This dynamic system must be precisely regulated to shuttle different cargo proteins between the ciliary tip and base. In this Cell Science at a Glance article and the accompanying poster, we discuss the current structural and mechanistic understanding of IFT trains and how they function as macromolecular machines to assemble the structure of the cilium.
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Affiliation(s)
- Mareike A Jordan
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Gaia Pigino
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Pfotenhauerstraße 108, 01307 Dresden, Germany.,Human Technopole, Via Cristina Belgioioso 171, 20157 Milan, Italy
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38
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May EA, Sroka TJ, Mick DU. Phosphorylation and Ubiquitylation Regulate Protein Trafficking, Signaling, and the Biogenesis of Primary Cilia. Front Cell Dev Biol 2021; 9:664279. [PMID: 33912570 PMCID: PMC8075051 DOI: 10.3389/fcell.2021.664279] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/09/2021] [Indexed: 12/30/2022] Open
Abstract
The primary cilium is a solitary, microtubule-based membrane protrusion extending from the surface of quiescent cells that senses the cellular environment and triggers specific cellular responses. The functions of primary cilia require not only numerous different components but also their regulated interplay. The cilium performs highly dynamic processes, such as cell cycle-dependent assembly and disassembly as well as delivery, modification, and removal of signaling components to perceive and process external signals. On a molecular level, these processes often rely on a stringent control of key modulatory proteins, of which the activity, localization, and stability are regulated by post-translational modifications (PTMs). While an increasing number of PTMs on ciliary components are being revealed, our knowledge on the identity of the modifying enzymes and their modulation is still limited. Here, we highlight recent findings on cilia-specific phosphorylation and ubiquitylation events. Shedding new light onto the molecular mechanisms that regulate the sensitive equilibrium required to maintain and remodel primary cilia functions, we discuss their implications for cilia biogenesis, protein trafficking, and cilia signaling processes.
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Affiliation(s)
- Elena A May
- Center of Human and Molecular Biology (ZHMB), Saarland University School of Medicine, Homburg, Germany.,Center for Molecular Signaling (PZMS), Department of Medical Biochemistry and Molecular Biology, Saarland University School of Medicine, Homburg, Germany
| | - Tommy J Sroka
- Center of Human and Molecular Biology (ZHMB), Saarland University School of Medicine, Homburg, Germany.,Center for Molecular Signaling (PZMS), Department of Medical Biochemistry and Molecular Biology, Saarland University School of Medicine, Homburg, Germany
| | - David U Mick
- Center of Human and Molecular Biology (ZHMB), Saarland University School of Medicine, Homburg, Germany.,Center for Molecular Signaling (PZMS), Department of Medical Biochemistry and Molecular Biology, Saarland University School of Medicine, Homburg, Germany
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39
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Arveseth CD, Happ JT, Hedeen DS, Zhu JF, Capener JL, Klatt Shaw D, Deshpande I, Liang J, Xu J, Stubben SL, Nelson IB, Walker MF, Kawakami K, Inoue A, Krogan NJ, Grunwald DJ, Hüttenhain R, Manglik A, Myers BR. Smoothened transduces Hedgehog signals via activity-dependent sequestration of PKA catalytic subunits. PLoS Biol 2021; 19:e3001191. [PMID: 33886552 PMCID: PMC8096101 DOI: 10.1371/journal.pbio.3001191] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 05/04/2021] [Accepted: 03/16/2021] [Indexed: 12/13/2022] Open
Abstract
The Hedgehog (Hh) pathway is essential for organ development, homeostasis, and regeneration. Dysfunction of this cascade drives several cancers. To control expression of pathway target genes, the G protein-coupled receptor (GPCR) Smoothened (SMO) activates glioma-associated (GLI) transcription factors via an unknown mechanism. Here, we show that, rather than conforming to traditional GPCR signaling paradigms, SMO activates GLI by binding and sequestering protein kinase A (PKA) catalytic subunits at the membrane. This sequestration, triggered by GPCR kinase (GRK)-mediated phosphorylation of SMO intracellular domains, prevents PKA from phosphorylating soluble substrates, releasing GLI from PKA-mediated inhibition. Our work provides a mechanism directly linking Hh signal transduction at the membrane to GLI transcription in the nucleus. This process is more fundamentally similar between species than prevailing hypotheses suggest. The mechanism described here may apply broadly to other GPCR- and PKA-containing cascades in diverse areas of biology.
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Affiliation(s)
- Corvin D. Arveseth
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - John T. Happ
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Danielle S. Hedeen
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Ju-Fen Zhu
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Jacob L. Capener
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Dana Klatt Shaw
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Ishan Deshpande
- Department of Pharmaceutical Chemistry, Department of Anaesthesia and Perioperative Care, University of California, San Francisco, California, United States of America
| | - Jiahao Liang
- Department of Pharmaceutical Chemistry, Department of Anaesthesia and Perioperative Care, University of California, San Francisco, California, United States of America
| | - Jiewei Xu
- Department of Cellular and Molecular Pharmacology, Quantitative Biosciences Institute, University of California, San Francisco, California, United States of America
- J. David Gladstone Institutes, San Francisco, California, United States of America
| | - Sara L. Stubben
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Isaac B. Nelson
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Madison F. Walker
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Kouki Kawakami
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Nevan J. Krogan
- Department of Cellular and Molecular Pharmacology, Quantitative Biosciences Institute, University of California, San Francisco, California, United States of America
- J. David Gladstone Institutes, San Francisco, California, United States of America
| | - David J. Grunwald
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Ruth Hüttenhain
- Department of Cellular and Molecular Pharmacology, Quantitative Biosciences Institute, University of California, San Francisco, California, United States of America
- J. David Gladstone Institutes, San Francisco, California, United States of America
| | - Aashish Manglik
- Department of Pharmaceutical Chemistry, Department of Anaesthesia and Perioperative Care, University of California, San Francisco, California, United States of America
| | - Benjamin R. Myers
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
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40
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HTR6 and SSTR3 targeting to primary cilia. Biochem Soc Trans 2021; 49:79-91. [PMID: 33599752 DOI: 10.1042/bst20191005] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 12/25/2020] [Accepted: 01/20/2021] [Indexed: 12/30/2022]
Abstract
Primary cilia are hair-like projections of the cell membrane supported by an inner microtubule scaffold, the axoneme, which polymerizes out of a membrane-docked centriole at the ciliary base. By working as specialized signaling compartments, primary cilia provide an optimal environment for many G protein-coupled receptors (GPCRs) and their effectors to efficiently transmit their signals to the rest of the cell. For this to occur, however, all necessary receptors and signal transducers must first accumulate at the ciliary membrane. Serotonin receptor 6 (HTR6) and Somatostatin receptor 3 (SSTR3) are two GPCRs whose signaling in brain neuronal cilia affects cognition and is implicated in psychiatric, neurodegenerative, and oncologic diseases. Over a decade ago, the third intracellular loops (IC3s) of HTR6 and SSTR3 were shown to contain ciliary localization sequences (CLSs) that, when grafted onto non-ciliary GPCRs, could drive their ciliary accumulation. Nevertheless, these CLSs were dispensable for ciliary targeting of HTR6 and SSTR3, suggesting the presence of additional CLSs, which we have recently identified in their C-terminal tails. Herein, we review the discovery and mapping of these CLSs, as well as the state of the art regarding how these CLSs may orchestrate ciliary accumulation of these GPCRs by controlling when and where they interact with the ciliary entry and exit machinery via adaptors such as TULP3, RABL2 and the BBSome.
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41
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Barnes CL, Malhotra H, Calvert PD. Compartmentalization of Photoreceptor Sensory Cilia. Front Cell Dev Biol 2021; 9:636737. [PMID: 33614665 PMCID: PMC7889997 DOI: 10.3389/fcell.2021.636737] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/07/2021] [Indexed: 12/12/2022] Open
Abstract
Functional compartmentalization of cells is a universal strategy for segregating processes that require specific components, undergo regulation by modulating concentrations of those components, or that would be detrimental to other processes. Primary cilia are hair-like organelles that project from the apical plasma membranes of epithelial cells where they serve as exclusive compartments for sensing physical and chemical signals in the environment. As such, molecules involved in signal transduction are enriched within cilia and regulating their ciliary concentrations allows adaptation to the environmental stimuli. The highly efficient organization of primary cilia has been co-opted by major sensory neurons, olfactory cells and the photoreceptor neurons that underlie vision. The mechanisms underlying compartmentalization of cilia are an area of intense current research. Recent findings have revealed similarities and differences in molecular mechanisms of ciliary protein enrichment and its regulation among primary cilia and sensory cilia. Here we discuss the physiological demands on photoreceptors that have driven their evolution into neurons that rely on a highly specialized cilium for signaling changes in light intensity. We explore what is known and what is not known about how that specialization appears to have driven unique mechanisms for photoreceptor protein and membrane compartmentalization.
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Affiliation(s)
| | | | - Peter D. Calvert
- Department of Ophthalmology and Visual Sciences, Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY, United States
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42
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BBS Proteins Affect Ciliogenesis and Are Essential for Hedgehog Signaling, but Not for Formation of iPSC-Derived RPE-65 Expressing RPE-Like Cells. Int J Mol Sci 2021; 22:ijms22031345. [PMID: 33572860 PMCID: PMC7866284 DOI: 10.3390/ijms22031345] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/23/2021] [Accepted: 01/24/2021] [Indexed: 12/31/2022] Open
Abstract
Bardet-Biedl syndrome (BBS) is a ciliopathy characterized by retinal dystrophy, renal cysts, obesity and polydactyly. BBS genes have been implicated in ciliogenesis, hedgehog signaling and retinal pigment epithelium maturation. BBS1 and BBS5 are members of the BBSome, implicated in cilia transport of proteins, and BBS10 is a member of the chaperonin-complex, mediating BBSome assembly. In this study, involvement of BBS1, BBS5 and BBS10 in ciliogenesis and hedgehog signaling were investigated in BBS-defective patient fibroblasts as well as in RPE-hTERT cells following siRNA-mediated knockdown of the BBS genes. Furthermore, the ability of BBS1-defective induced pluripotent stem-cells (iPSCs) to differentiate into RPE cells was assessed. We report that cells lacking functional BBS5 or BBS10 have a reduced number of primary cilia, whereas cells lacking functional BBS1 display shorter primary cilia compared to wild-type cells. Hedgehog signaling was substantially impaired and Smoothened, a component of hedgehog signaling, was trapped inside the cilia of the BBS-defective cells, even in the absence of Smoothened agonist. Preliminary results demonstrated the ability of BBS1-defective iPSC to differentiate into RPE-65 expressing RPE-like cells. The BBS1-/--defective RPE-like cells were less pigmented, compared to RPE-like cells differentiated from control iPSCs, indicating an impact of BBS1 on RPE maturation.
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43
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Abstract
Recent work has resolved the established links between β-arrestin 2 and the BBSome in controlling ciliary GPCR localization by showing that β-arrestin 2 regulates the addition of K63-linked ubiquitin chains to tag proteins for removal from the cilia via the BBSome.
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Affiliation(s)
- Eduardo D Gigante
- Neuroscience Graduate Program, Emory University, Atlanta, GA 30322, USA; Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Tamara Caspary
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA.
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44
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Bosakova M, Abraham SP, Nita A, Hruba E, Buchtova M, Taylor SP, Duran I, Martin J, Svozilova K, Barta T, Varecha M, Balek L, Kohoutek J, Radaszkiewicz T, Pusapati GV, Bryja V, Rush ET, Thiffault I, Nickerson DA, Bamshad MJ, Rohatgi R, Cohn DH, Krakow D, Krejci P. Mutations in GRK2 cause Jeune syndrome by impairing Hedgehog and canonical Wnt signaling. EMBO Mol Med 2020; 12:e11739. [PMID: 33200460 PMCID: PMC7645380 DOI: 10.15252/emmm.201911739] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 09/08/2020] [Accepted: 09/15/2020] [Indexed: 12/15/2022] Open
Abstract
Mutations in genes affecting primary cilia cause ciliopathies, a diverse group of disorders often affecting skeletal development. This includes Jeune syndrome or asphyxiating thoracic dystrophy (ATD), an autosomal recessive skeletal disorder. Unraveling the responsible molecular pathology helps illuminate mechanisms responsible for functional primary cilia. We identified two families with ATD caused by loss-of-function mutations in the gene encoding adrenergic receptor kinase 1 (ADRBK1 or GRK2). GRK2 cells from an affected individual homozygous for the p.R158* mutation resulted in loss of GRK2, and disrupted chondrocyte growth and differentiation in the cartilage growth plate. GRK2 null cells displayed normal cilia morphology, yet loss of GRK2 compromised cilia-based signaling of Hedgehog (Hh) pathway. Canonical Wnt signaling was also impaired, manifested as a failure to respond to Wnt ligand due to impaired phosphorylation of the Wnt co-receptor LRP6. We have identified GRK2 as an essential regulator of skeletogenesis and demonstrate how both Hh and Wnt signaling mechanistically contribute to skeletal ciliopathies.
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Affiliation(s)
- Michaela Bosakova
- Department of BiologyFaculty of MedicineMasaryk UniversityBrnoCzech Republic
- International Clinical Research CenterSt. Anne's University HospitalBrnoCzech Republic
- Institute of Animal Physiology and Genetics of the CASBrnoCzech Republic
| | - Sara P Abraham
- Department of BiologyFaculty of MedicineMasaryk UniversityBrnoCzech Republic
| | - Alexandru Nita
- Department of BiologyFaculty of MedicineMasaryk UniversityBrnoCzech Republic
| | - Eva Hruba
- Institute of Animal Physiology and Genetics of the CASBrnoCzech Republic
| | - Marcela Buchtova
- Institute of Animal Physiology and Genetics of the CASBrnoCzech Republic
| | - S Paige Taylor
- Department of Orthopaedic SurgeryDavid Geffen School of Medicine at UCLALos AngelesCAUSA
| | - Ivan Duran
- Department of Orthopaedic SurgeryDavid Geffen School of Medicine at UCLALos AngelesCAUSA
| | - Jorge Martin
- Department of Orthopaedic SurgeryDavid Geffen School of Medicine at UCLALos AngelesCAUSA
| | - Katerina Svozilova
- Department of BiologyFaculty of MedicineMasaryk UniversityBrnoCzech Republic
- Institute of Animal Physiology and Genetics of the CASBrnoCzech Republic
| | - Tomas Barta
- Department of Histology and EmbryologyFaculty of MedicineMasaryk UniversityBrnoCzech Republic
| | - Miroslav Varecha
- Department of BiologyFaculty of MedicineMasaryk UniversityBrnoCzech Republic
| | - Lukas Balek
- Department of BiologyFaculty of MedicineMasaryk UniversityBrnoCzech Republic
| | | | - Tomasz Radaszkiewicz
- Institute of Experimental BiologyFaculty of ScienceMasaryk UniversityBrnoCzech Republic
| | - Ganesh V Pusapati
- Department of BiochemistryStanford UniversityPalo AltoCAUSA
- Department of MedicineStanford UniversityPalo AltoCAUSA
| | - Vitezslav Bryja
- Institute of Experimental BiologyFaculty of ScienceMasaryk UniversityBrnoCzech Republic
| | - Eric T Rush
- Children's Mercy Kansas City, Center for Pediatric Genomic MedicineKansas CityMOUSA
- Department of PediatricsUniversity of MissouriKansas CityMOUSA
| | - Isabelle Thiffault
- Children's Mercy Kansas City, Center for Pediatric Genomic MedicineKansas CityMOUSA
- Department of PediatricsUniversity of MissouriKansas CityMOUSA
| | | | - Michael J Bamshad
- Department of Genome SciencesUniversity of WashingtonSeattleWAUSA
- Department of PediatricsUniversity of WashingtonSeattleWAUSA
- Division of Genetic MedicineSeattle Children's HospitalSeattleWAUSA
| | | | - Rajat Rohatgi
- Department of BiochemistryStanford UniversityPalo AltoCAUSA
- Department of MedicineStanford UniversityPalo AltoCAUSA
| | - Daniel H Cohn
- Department of Orthopaedic SurgeryDavid Geffen School of Medicine at UCLALos AngelesCAUSA
- Department of Molecular Cell and Developmental BiologyUniversity of California at Los AngelesLos AngelesCAUSA
| | - Deborah Krakow
- Department of Orthopaedic SurgeryDavid Geffen School of Medicine at UCLALos AngelesCAUSA
- Department of Human GeneticsDavid Geffen School of Medicine at UCLALos AngelesCAUSA
- Department of Obstetrics and GynecologyDavid Geffen School of Medicine at UCLALos AngelesCAUSA
| | - Pavel Krejci
- Department of BiologyFaculty of MedicineMasaryk UniversityBrnoCzech Republic
- International Clinical Research CenterSt. Anne's University HospitalBrnoCzech Republic
- Institute of Animal Physiology and Genetics of the CASBrnoCzech Republic
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45
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Webb S, Mukhopadhyay AG, Roberts AJ. Intraflagellar transport trains and motors: Insights from structure. Semin Cell Dev Biol 2020; 107:82-90. [PMID: 32684327 PMCID: PMC7561706 DOI: 10.1016/j.semcdb.2020.05.021] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 05/19/2020] [Accepted: 05/26/2020] [Indexed: 11/17/2022]
Abstract
Intraflagellar transport (IFT) sculpts the proteome of cilia and flagella; the antenna-like organelles found on the surface of virtually all human cell types. By delivering proteins to the growing ciliary tip, recycling turnover products, and selectively transporting signalling molecules, IFT has critical roles in cilia biogenesis, quality control, and signal transduction. IFT involves long polymeric arrays, termed IFT trains, which move to and from the ciliary tip under the power of the microtubule-based motor proteins kinesin-II and dynein-2. Recent top-down and bottom-up structural biology approaches are converging on the molecular architecture of the IFT train machinery. Here we review these studies, with a focus on how kinesin-II and dynein-2 assemble, attach to IFT trains, and undergo precise regulation to mediate bidirectional transport.
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Affiliation(s)
- Stephanie Webb
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London, United Kingdom
| | - Aakash G Mukhopadhyay
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London, United Kingdom
| | - Anthony J Roberts
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London, United Kingdom.
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46
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Larsen LJ, Møller LB. Crosstalk of Hedgehog and mTORC1 Pathways. Cells 2020; 9:cells9102316. [PMID: 33081032 PMCID: PMC7603200 DOI: 10.3390/cells9102316] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 09/30/2020] [Accepted: 10/13/2020] [Indexed: 02/07/2023] Open
Abstract
Hedgehog (Hh) signaling and mTOR signaling, essential for embryonic development and cellular metabolism, are both coordinated by the primary cilium. Observations from cancer cells strongly indicate crosstalk between Hh and mTOR signaling. This hypothesis is supported by several studies: Evidence points to a TGFβ-mediated crosstalk; Increased PI3K/AKT/mTOR activity leads to increased Hh signaling through regulation of the GLI transcription factors; increased Hh signaling regulates mTORC1 activity positively by upregulating NKX2.2, leading to downregulation of negative mTOR regulators; GSK3 and AMPK are, as members of both signaling pathways, potentially important links between Hh and mTORC1 signaling; The kinase DYRK2 regulates Hh positively and mTORC1 signaling negatively. In contrast, both positive and negative regulation of Hh has been observed for DYRK1A and DYRK1B, which both regulate mTORC1 signaling positively. Based on crosstalk observed between cilia, Hh, and mTORC1, we suggest that the interaction between Hh and mTORC1 is more widespread than it appears from our current knowledge. Although many studies focusing on crosstalk have been carried out, contradictory observations appear and the interplay involving multiple partners is far from solved.
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Kong JH, Young CB, Pusapati GV, Patel CB, Ho S, Krishnan A, Lin JHI, Devine W, Moreau de Bellaing A, Athni TS, Aravind L, Gunn TM, Lo CW, Rohatgi R. A Membrane-Tethered Ubiquitination Pathway Regulates Hedgehog Signaling and Heart Development. Dev Cell 2020; 55:432-449.e12. [PMID: 32966817 PMCID: PMC7686252 DOI: 10.1016/j.devcel.2020.08.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/23/2020] [Accepted: 08/27/2020] [Indexed: 12/30/2022]
Abstract
The etiology of congenital heart defects (CHDs), which are among the most common human birth defects, is poorly understood because of its complex genetic architecture. Here, we show that two genes implicated in CHDs, Megf8 and Mgrn1, interact genetically and biochemically to regulate the strength of Hedgehog signaling in target cells. MEGF8, a transmembrane protein, and MGRN1, a RING superfamily E3 ligase, assemble to form a receptor-like ubiquitin ligase complex that catalyzes the ubiquitination and degradation of the Hedgehog pathway transducer Smoothened. Homozygous Megf8 and Mgrn1 mutations increased Smoothened abundance and elevated sensitivity to Hedgehog ligands. While mice heterozygous for loss-of-function Megf8 or Mgrn1 mutations were normal, double heterozygous embryos exhibited an incompletely penetrant syndrome of CHDs with heterotaxy. Thus, genetic interactions can arise from biochemical mechanisms that calibrate morphogen signaling strength, a conclusion broadly relevant for the many human diseases in which oligogenic inheritance is emerging as a mechanism for heritability.
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Affiliation(s)
- Jennifer H Kong
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Cullen B Young
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, USA
| | - Ganesh V Pusapati
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Chandni B Patel
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sebastian Ho
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, USA
| | - Arunkumar Krishnan
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Jiuann-Huey Ivy Lin
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, USA
| | - William Devine
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, USA
| | - Anne Moreau de Bellaing
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, USA; Department of Pediatric Cardiology, Necker-Sick Children Hospital and The University of Paris Descartes, Paris 75015, France
| | - Tejas S Athni
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - L Aravind
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Teresa M Gunn
- McLaughlin Research Institute, Great Falls, MT 59405, USA.
| | - Cecilia W Lo
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, USA.
| | - Rajat Rohatgi
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
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48
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Petriman NA, Lorentzen E. Structural insights into the architecture and assembly of eukaryotic flagella. MICROBIAL CELL (GRAZ, AUSTRIA) 2020; 7:289-299. [PMID: 33150161 PMCID: PMC7590530 DOI: 10.15698/mic2020.11.734] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/07/2020] [Accepted: 09/14/2020] [Indexed: 12/16/2022]
Abstract
Cilia and flagella are slender projections found on most eukaryotic cells including unicellular organisms such as Chlamydomonas, Trypanosoma and Tetrahymena, where they serve motility and signaling functions. The cilium is a large molecular machine consisting of hundreds of different proteins that are trafficked into the organelle to organize a repetitive microtubule-based axoneme. Several recent studies took advantage of improved cryo-EM methodology to unravel the high-resolution structures of ciliary complexes. These include the recently reported purification and structure determination of axonemal doublet microtubules from the green algae Chlamydomonas reinhardtii, which allows for the modeling of more than 30 associated protein factors to provide deep molecular insight into the architecture and repetitive nature of doublet microtubules. In addition, we will review several recent contributions that dissect the structure and function of ciliary trafficking complexes that ferry structural and signaling components between the cell body and the cilium organelle.
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Affiliation(s)
- Narcis-Adrian Petriman
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, DK-8000 Aarhus C, Denmark
| | - Esben Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, DK-8000 Aarhus C, Denmark
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