1
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Kulkarni PP, Ekhlak M, Dash D. Non-canonical non-genomic morphogen signaling in anucleate platelets: a critical determinant of prothrombotic function in circulation. Cell Commun Signal 2024; 22:13. [PMID: 38172855 PMCID: PMC10763172 DOI: 10.1186/s12964-023-01448-y] [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: 11/08/2023] [Accepted: 12/19/2023] [Indexed: 01/05/2024] Open
Abstract
Circulating platelets derived from bone marrow megakaryocytes play a central role in thrombosis and hemostasis. Despite being anucleate, platelets express several proteins known to have nuclear niche. These include transcription factors and steroid receptors whose non-genomic functions are being elucidated in platelets. Quite remarkably, components of some of the best-studied morphogen pathways, namely Notch, Sonic Hedgehog (Shh), and Wnt have also been described in recent years in platelets, which regulate platelet function in the context of thrombosis as well as influence their survival. Shh and Notch pathways in stimulated platelets establish feed-forward loops of autocrine/juxtacrine/paracrine non-canonical signaling that helps perpetuate thrombosis. On the other hand, non-canonical Wnt signaling is part of a negative feedback loop for restricting platelet activation and possibly limiting thrombus growth. The present review will provide an overview of these signaling pathways in general. We will then briefly discuss the non-genomic roles of transcription factors and steroid receptors in platelet activation. This will be followed by an elaborate description of morphogen signaling in platelets with a focus on their bearing on platelet activation leading to hemostasis and thrombosis as well as their potential for therapeutic targeting in thrombotic disorders.
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Affiliation(s)
- Paresh P Kulkarni
- Center for Advanced Research on Platelet Signaling and Thrombosis Biology, Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India.
| | - Mohammad Ekhlak
- Center for Advanced Research on Platelet Signaling and Thrombosis Biology, Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India
| | - Debabrata Dash
- Center for Advanced Research on Platelet Signaling and Thrombosis Biology, Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India.
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2
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Fan J, Tong G, Chen X, Li S, Yu Y, Zhu S, Zhu K, Hu Z, Dong Y, Chen R, Zhu J, Gong W, Hu Z, Zhou B, Chen Y, Jin L, Cong W. CK2 blockade alleviates liver fibrosis by suppressing activation of hepatic stellate cells via the Hedgehog pathway. Br J Pharmacol 2023; 180:44-61. [PMID: 36070072 DOI: 10.1111/bph.15945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 08/29/2022] [Accepted: 09/02/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND AND PURPOSE Liver fibrosis is a serious cause of morbidity and mortality worldwide characterized by accumulation of extracellular matrix produced by hepatic stellate cells (HSCs). The protein kinase CK2 is a pro-survival kinase overexpressed in human tumours. However, the biological role of CK2 in liver fibrosis is largely unknown. We aimed to investigate the mechanism by which CK2 promotes liver fibrosis. EXPERIMENTAL APPROACH In vitro, LX-2 cells were stimulated with transforming growth factor-β (TGF-β). HSCs were also isolated for research. In vivo, the adeno-associated virus AAV-sh-csnk2a1 was used to knockdown CK2α specifically in HSCs, and CX-4945 was used to pharmacologically inhibit the enzymatic activity of CK2 in murine models of fibrosis induced by carbon tetrachloride (CCl4 ) and a 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet. Histological and biochemical analyses were performed to study the involvement of CK2 in regulation of fibrogenic and fibrolytic factors as well as activation properties of HSCs. KEY RESULTS HSC-specific genetic invalidation of CK2α or pharmacological inhibition of CK2 protected mice treated with CCl4 or fed a DDC diet against liver fibrosis and HSC accumulation. Mechanistically, CK2α, which bound to Smoothened (SMO), was a positive regulator of the Hedgehog signal transduction pathway. CK2 prevented ubiquitination and proteasomal degradation of SMO, which was abolished by knockdown of CK2α or pharmacological inhibition of CK2. CONCLUSIONS AND IMPLICATIONS CK2 activation is critical to sustain the activated and fibrogenic phenotype of HSCs via SMO stabilization. Therefore, inactivation of CK2 by CX-4945 may be of therapeutic interest for liver fibrotic diseases.
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Affiliation(s)
- Junfu Fan
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Gaozan Tong
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xixi Chen
- Department of Pharmacy, Taizhou Central Hospital (Taizhou University Hospital), Taizhou, Zhejiang, China
| | - Santie Li
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Ying Yu
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Shunan Zhu
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Kunxuan Zhu
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zijing Hu
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yonggan Dong
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Rui Chen
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Junjie Zhu
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Wenjie Gong
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zhicheng Hu
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Bin Zhou
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yiming Chen
- Department of Hepatobiliary Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Litai Jin
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Weitao Cong
- School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
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3
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Platova S, Poliushkevich L, Kulakova M, Nesterenko M, Starunov V, Novikova E. Gotta Go Slow: Two Evolutionarily Distinct Annelids Retain a Common Hedgehog Pathway Composition, Outlining Its Pan-Bilaterian Core. Int J Mol Sci 2022; 23:ijms232214312. [PMID: 36430788 PMCID: PMC9695228 DOI: 10.3390/ijms232214312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/11/2022] [Accepted: 11/13/2022] [Indexed: 11/19/2022] Open
Abstract
Hedgehog signaling is one of the key regulators of morphogenesis, cell differentiation, and regeneration. While the Hh pathway is present in all bilaterians, it has mainly been studied in model animals such as Drosophila and vertebrates. Despite the conservatism of its core components, mechanisms of signal transduction and additional components vary in Ecdysozoa and Deuterostomia. Vertebrates have multiple copies of the pathway members, which complicates signaling implementation, whereas model ecdysozoans appear to have lost some components due to fast evolution rates. To shed light on the ancestral state of Hh signaling, models from the third clade, Spiralia, are needed. In our research, we analyzed the transcriptomes of two spiralian animals, errantial annelid Platynereis dumerilii (Nereididae) and sedentarian annelid Pygospio elegans (Spionidae). We found that both annelids express almost all Hh pathway components present in Drosophila and mouse. We performed a phylogenetic analysis of the core pathway components and built multiple sequence alignments of the additional key members. Our results imply that the Hh pathway compositions of both annelids share more similarities with vertebrates than with the fruit fly. Possessing an almost complete set of single-copy Hh pathway members, lophotrochozoan signaling composition may reflect the ancestral features of all three bilaterian branches.
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Affiliation(s)
- Sofia Platova
- Faculty of Biology, St. Petersburg State University, Saint Petersburg 199034, Russia
- Zoological Institute RAS, Saint Petersburg 199034, Russia
| | | | - Milana Kulakova
- Faculty of Biology, St. Petersburg State University, Saint Petersburg 199034, Russia
- Zoological Institute RAS, Saint Petersburg 199034, Russia
- Correspondence: (M.K.); (E.N.)
| | | | - Viktor Starunov
- Faculty of Biology, St. Petersburg State University, Saint Petersburg 199034, Russia
- Zoological Institute RAS, Saint Petersburg 199034, Russia
| | - Elena Novikova
- Faculty of Biology, St. Petersburg State University, Saint Petersburg 199034, Russia
- Zoological Institute RAS, Saint Petersburg 199034, Russia
- Correspondence: (M.K.); (E.N.)
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4
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Gonçalves Antunes M, Sanial M, Contremoulins V, Carvalho S, Plessis A, Becam I. High hedgehog signaling is transduced by a multikinase-dependent switch controlling the apico-basal distribution of the GPCR smoothened. eLife 2022; 11:79843. [PMID: 36083801 PMCID: PMC9462849 DOI: 10.7554/elife.79843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
The oncogenic G-protein-coupled receptor (GPCR) Smoothened (SMO) is a key transducer of the hedgehog (HH) morphogen, which plays an essential role in the patterning of epithelial structures. Here, we examine how HH controls SMO subcellular localization and activity in a polarized epithelium using the Drosophila wing imaginal disc as a model. We provide evidence that HH promotes the stabilization of SMO by switching its fate after endocytosis toward recycling. This effect involves the sequential and additive action of protein kinase A, casein kinase I, and the Fused (FU) kinase. Moreover, in the presence of very high levels of HH, the second effect of FU leads to the local enrichment of SMO in the most basal domain of the cell membrane. Together, these results link the morphogenetic effects of HH to the apico-basal distribution of SMO and provide a novel mechanism for the regulation of a GPCR.
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Affiliation(s)
| | | | | | | | - Anne Plessis
- Université Paris Cité, CNRS, Institut Jacques Monod
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5
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Chen X, Shi Z, Yang F, Zhou T, Xie S. Deciphering cilia and ciliopathies using proteomic approaches. FEBS J 2022; 290:2590-2603. [PMID: 35633520 DOI: 10.1111/febs.16538] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 04/21/2022] [Accepted: 05/19/2022] [Indexed: 12/01/2022]
Abstract
Cilia are microtubule-based organelles that protrude from the cell surface and play crucial roles in cellular signaling pathways and extracellular fluid movement. Defects in the ciliary structures and functions are implicated in a set of hereditary disorders, including polycystic kidney disease, nephronophthisis, and Bardet-Biedl syndrome, which are collectively termed as ciliopathies. The application of mass spectrometry-based proteomic approaches to explore ciliary components provides important clues for understanding their physiological and pathological roles. In this review, we focus primarily on proteomic studies involving the identification of proteins in motile cilia and primary cilia, proteomes in ciliopathies, and interactomes of ciliopathy proteins. Collectively, the integration of these data sets will be beneficial for the comprehensive understanding of ciliary structures and exploring potential biomarkers and therapeutic targets for ciliopathies.
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Affiliation(s)
- Xiying Chen
- The Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China.,Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhouyuanjing Shi
- Department of Gastroenterology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Feng Yang
- The Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China.,Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Tianhua Zhou
- Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
| | - Shanshan Xie
- The Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China.,Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China
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6
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He T, Fan Y, Wang Y, Liu M, Zhu AJ. Dissection of the microRNA Network Regulating Hedgehog Signaling in Drosophila. Front Cell Dev Biol 2022; 10:866491. [PMID: 35573695 PMCID: PMC9096565 DOI: 10.3389/fcell.2022.866491] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 04/08/2022] [Indexed: 11/13/2022] Open
Abstract
The evolutionarily conserved Hedgehog (Hh) signaling plays a critical role in embryogenesis and adult tissue homeostasis. Aberrant Hh signaling often leads to various forms of developmental anomalies and cancer. Since altered microRNA (miRNA) expression is associated with developmental defects and tumorigenesis, it is not surprising that several miRNAs have been found to regulate Hh signaling. However, these miRNAs are mainly identified through small-scale in vivo screening or in vitro assays. As miRNAs preferentially reduce target gene expression via the 3' untranslated region, we analyzed the effect of reduced expression of core components of the Hh signaling cascade on downstream signaling activity, and generated a transgenic Drosophila toolbox of in vivo miRNA sensors for core components of Hh signaling, including hh, patched (ptc), smoothened (smo), costal 2 (cos2), fused (fu), Suppressor of fused (Su(fu)), and cubitus interruptus (ci). With these tools in hand, we performed a genome-wide in vivo miRNA overexpression screen in the developing Drosophila wing imaginal disc. Of the twelve miRNAs identified, seven were not previously reported in the in vivo Hh regulatory network. Moreover, these miRNAs may act as general regulators of Hh signaling, as their overexpression disrupts Hh signaling-mediated cyst stem cell maintenance during spermatogenesis. To identify direct targets of these newly discovered miRNAs, we used the miRNA sensor toolbox to show that miR-10 and miR-958 directly target fu and smo, respectively, while the other five miRNAs act through yet-to-be-identified targets other than the seven core components of Hh signaling described above. Importantly, through loss-of-function analysis, we found that endogenous miR-10 and miR-958 target fu and smo, respectively, whereas deletion of the other five miRNAs leads to altered expression of Hh signaling components, suggesting that these seven newly discovered miRNAs regulate Hh signaling in vivo. Given the powerful effects of these miRNAs on Hh signaling, we believe that identifying their bona fide targets of the other five miRNAs will help reveal important new players in the Hh regulatory network.
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Affiliation(s)
- Tao He
- 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
| | - Yu Fan
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, China
| | - Yao Wang
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, China
| | - 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
| | - 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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7
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Phenotypical and genetical characterization of the Mad 1-2 allele during Drosophila wing development. Cells Dev 2021; 169:203761. [PMID: 34875394 DOI: 10.1016/j.cdev.2021.203761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 11/25/2021] [Accepted: 11/26/2021] [Indexed: 11/23/2022]
Abstract
Growth and patterning of Drosophila wing depends upon the sequential organizing activities of Hedgehog (Hh) and Decapentaplegic (Dpp) signaling pathways. The Hh signaling directly activates the expression of dpp through the transcription factor cubitus interruptus (Ci). Dpp itself functions as a long-range morphogen to promote cell proliferation and differentiation through an essential transcription factor encoded by Mad. Here we report that the Mad1-2 allele exhibits phenotypes distinct from classical Dpp pathway mutants in the developing wing. The activity of Dpp signaling is attenuated in Mad1-2 mutant cells. However, activation of Dpp signaling is found in a subset of cells surrounding homozygous Mad1-2 clones when the clones are located at the anterior compartment of wing disc. Further analysis reveals that Mad1-2 mutant cells display high level of Hh signaling activity and accumulate significant amount of Ci. Unexpectedly, whole genome resequencing identifies multiple mutations in the 3'UTR region of Pka-C1 genomic loci in the Mad1-2 stock. We provide genetic and molecular evidence that the Pka-C1 mutations carried by Mad1-2 likely underlies the observed Hh signaling defects. Therefore, the contribution of Pka-C1 mutation should be taken in consideration when analyzing Mad1-2 phenotypes. The isolation of independent Mad and Pka-C1 alleles from the Mad1-2 stock further supports our conclusions.
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8
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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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9
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Ostalé CM, Esteban N, López-Varea A, de Celis JF. Functional requirements of protein kinases and phosphatases in the development of the Drosophila melanogaster wing. G3-GENES GENOMES GENETICS 2021; 11:6380433. [PMID: 34599799 PMCID: PMC8664455 DOI: 10.1093/g3journal/jkab348] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 09/06/2021] [Indexed: 11/14/2022]
Abstract
Protein kinases and phosphatases constitute a large family of conserved enzymes that control a variety of biological processes by regulating the phosphorylation state of target proteins. They play fundamental regulatory roles during cell cycle progression and signaling, among other key aspects of multicellular development. The complement of protein kinases and phosphatases includes approximately 326 members in Drosophila, and they have been the subject of several functional screens searching for novel components of signaling pathways and regulators of cell division and survival. These approaches have been carried out mostly in cell cultures using RNA interference to evaluate the contribution of each protein in different functional assays, and have contributed significantly to assign specific roles to the corresponding genes. In this work we describe the results of an evaluation of the Drosophila complement of kinases and phosphatases using the wing as a system to identify their functional requirements in vivo. We also describe the results of several modifying screens aiming to identify among the set of protein kinases and phosphatases additional components or regulators of the activities of the Epidermal Growth Factor and Insulin receptors signaling pathways.
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Affiliation(s)
- Cristina M Ostalé
- Centro de Biología Molecular "Severo Ochoa", CSIC and Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Nuria Esteban
- Centro de Biología Molecular "Severo Ochoa", CSIC and Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Ana López-Varea
- Centro de Biología Molecular "Severo Ochoa", CSIC and Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Jose F de Celis
- Centro de Biología Molecular "Severo Ochoa", CSIC and Universidad Autónoma de Madrid, Madrid 28049, Spain
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10
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Abraham SP, Nita A, Krejci P, Bosakova M. Cilia kinases in skeletal development and homeostasis. Dev Dyn 2021; 251:577-608. [PMID: 34582081 DOI: 10.1002/dvdy.426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/22/2021] [Accepted: 09/22/2021] [Indexed: 11/08/2022] Open
Abstract
Primary cilia are dynamic compartments that regulate multiple aspects of cellular signaling. The production, maintenance, and function of cilia involve more than 1000 genes in mammals, and their mutations disrupt the ciliary signaling which manifests in a plethora of pathological conditions-the ciliopathies. Skeletal ciliopathies are genetic disorders affecting the development and homeostasis of the skeleton, and encompass a broad spectrum of pathologies ranging from isolated polydactyly to lethal syndromic dysplasias. The recent advances in forward genetics allowed for the identification of novel regulators of skeletogenesis, and revealed a growing list of ciliary proteins that are critical for signaling pathways implicated in bone physiology. Among these, a group of protein kinases involved in cilia assembly, maintenance, signaling, and disassembly has emerged. In this review, we summarize the functions of cilia kinases in skeletal development and disease, and discuss the available and upcoming treatment options.
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Affiliation(s)
- Sara P Abraham
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Alexandru Nita
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Pavel Krejci
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic.,Institute of Animal Physiology and Genetics of the CAS, Brno, Czech Republic.,International Clinical Research Center, St. Anne's University Hospital, Brno, Czech Republic
| | - Michaela Bosakova
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic.,Institute of Animal Physiology and Genetics of the CAS, Brno, Czech Republic.,International Clinical Research Center, St. Anne's University Hospital, Brno, Czech Republic
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11
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Mechanisms of Smoothened Regulation in Hedgehog Signaling. Cells 2021; 10:cells10082138. [PMID: 34440907 PMCID: PMC8391454 DOI: 10.3390/cells10082138] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/05/2021] [Accepted: 08/16/2021] [Indexed: 12/21/2022] Open
Abstract
The seven-transmembrane protein, Smoothened (SMO), has shown to be critical for the hedgehog (HH) signal transduction on the cell membrane (and the cilium in vertebrates). SMO is subjected to multiple types of post-translational regulations, including phosphorylation, ubiquitination, and sumoylation, which alter SMO intracellular trafficking and cell surface accumulation. Recently, SMO is also shown to be regulated by small molecules, such as oxysterol, cholesterol, and phospholipid. The activity of SMO must be very well balanced by these different mechanisms in vivo because the malfunction of SMO will not only cause developmental defects in early stages, but also induce cancers in late stages. Here, we discuss the activation and inactivation of SMO by different mechanisms to better understand how SMO is regulated by the graded HH signaling activity that eventually governs distinct development outcomes.
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12
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Nita A, Abraham SP, Krejci P, Bosakova M. Oncogenic FGFR Fusions Produce Centrosome and Cilia Defects by Ectopic Signaling. Cells 2021; 10:1445. [PMID: 34207779 PMCID: PMC8227969 DOI: 10.3390/cells10061445] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/27/2021] [Accepted: 06/07/2021] [Indexed: 12/12/2022] Open
Abstract
A single primary cilium projects from most vertebrate cells to guide cell fate decisions. A growing list of signaling molecules is found to function through cilia and control ciliogenesis, including the fibroblast growth factor receptors (FGFR). Aberrant FGFR activity produces abnormal cilia with deregulated signaling, which contributes to pathogenesis of the FGFR-mediated genetic disorders. FGFR lesions are also found in cancer, raising a possibility of cilia involvement in the neoplastic transformation and tumor progression. Here, we focus on FGFR gene fusions, and discuss the possible mechanisms by which they function as oncogenic drivers. We show that a substantial portion of the FGFR fusion partners are proteins associated with the centrosome cycle, including organization of the mitotic spindle and ciliogenesis. The functions of centrosome proteins are often lost with the gene fusion, leading to haploinsufficiency that induces cilia loss and deregulated cell division. We speculate that this complements the ectopic FGFR activity and drives the FGFR fusion cancers.
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Affiliation(s)
- Alexandru Nita
- Department of Biology, Faculty of Medicine, Masaryk University, 62500 Brno, Czech Republic; (A.N.); (S.P.A.); (P.K.)
| | - Sara P. Abraham
- Department of Biology, Faculty of Medicine, Masaryk University, 62500 Brno, Czech Republic; (A.N.); (S.P.A.); (P.K.)
| | - Pavel Krejci
- Department of Biology, Faculty of Medicine, Masaryk University, 62500 Brno, Czech Republic; (A.N.); (S.P.A.); (P.K.)
- Institute of Animal Physiology and Genetics of the CAS, 60200 Brno, Czech Republic
- International Clinical Research Center, St. Anne’s University Hospital, 65691 Brno, Czech Republic
| | - Michaela Bosakova
- Department of Biology, Faculty of Medicine, Masaryk University, 62500 Brno, Czech Republic; (A.N.); (S.P.A.); (P.K.)
- Institute of Animal Physiology and Genetics of the CAS, 60200 Brno, Czech Republic
- International Clinical Research Center, St. Anne’s University Hospital, 65691 Brno, Czech Republic
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13
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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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14
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Liu M, Liu A, Wang J, Zhang Y, Li Y, Su Y, Zhu AJ. Competition between two phosphatases fine-tunes Hedgehog signaling. J Cell Biol 2020; 220:211641. [PMID: 33373452 PMCID: PMC7774589 DOI: 10.1083/jcb.202010078] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/26/2020] [Accepted: 12/02/2020] [Indexed: 12/29/2022] Open
Abstract
Hedgehog (Hh) signaling is essential for embryonic development and adult homeostasis. How its signaling activity is fine-tuned in response to fluctuated Hh gradient is less known. Here, we identify protein phosphatase V (PpV), the catalytic subunit of protein phosphatase 6, as a homeostatic regulator of Hh signaling. PpV is genetically upstream of widerborst (wdb), which encodes a regulatory subunit of PP2A that modulates high-level Hh signaling. We show that PpV negatively regulates Wdb stability independent of phosphatase activity of PpV, by competing with the catalytic subunit of PP2A for Wdb association, leading to Wdb ubiquitination and subsequent proteasomal degradation. Thus, regulated Wdb stability, maintained through competition between two closely related phosphatases, ensures graded Hh signaling. Interestingly, PpV expression is regulated by Hh signaling. Therefore, PpV functions as a Hh activity sensor that regulates Wdb-mediated PP2A activity through feedback mechanisms to maintain Hh signaling homeostasis.
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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
| | - Aiguo 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
| | - Jie Wang
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, China
| | - Yansong Zhang
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, China
| | - Yajuan Li
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, China
| | - Ying Su
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China,Correspondence to Ying Su:
| | - 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,Alan Jian Zhu:
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15
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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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16
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Protein phosphatase 4 promotes Hedgehog signaling through dephosphorylation of Suppressor of fused. Cell Death Dis 2020; 11:686. [PMID: 32826873 PMCID: PMC7442787 DOI: 10.1038/s41419-020-02843-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 07/29/2020] [Accepted: 07/30/2020] [Indexed: 01/04/2023]
Abstract
Reversible phosphorylation of Suppressor of fused (Sufu) is essential for Sonic Hedgehog (Shh) signal transduction. Sufu is stabilized under dual phosphorylation of protein kinase A (PKA) and glycogen synthase kinase 3β (GSK3β). Its phosphorylation is reduced with the activation of Shh signaling. However, the phosphatase in this reversible phosphorylation has not been found. Taking advantage of a proteomic approach, we identified Protein phosphatase 4 regulatory subunit 2 (Ppp4r2), an interacting protein of Sufu. Shh signaling promotes the interaction of these two proteins in the nucleus, and Ppp4 also promotes dephosphorylation of Sufu, leading to its degradation and enhancing the Gli1 transcriptional activity. Finally, Ppp4-mediated dephosphorylation of Sufu promotes proliferation of medulloblastoma tumor cells, and expression of Ppp4 is positively correlated with up-regulation of Shh pathway target genes in the Shh-subtype medulloblastoma, underscoring the important role of this regulation in Shh signaling.
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17
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Mo D, Chen Y, Jiang N, Shen J, Zhang J. Investigation of Isoform Specific Functions of the V-ATPase a Subunit During Drosophila Wing Development. Front Genet 2020; 11:723. [PMID: 32754202 PMCID: PMC7365883 DOI: 10.3389/fgene.2020.00723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 06/15/2020] [Indexed: 12/12/2022] Open
Abstract
The vacuolar ATPases (V-ATPases) are ATP-dependent proton pumps that play vital roles in eukaryotic cells. Insect V-ATPases are required in nearly all epithelial tissues to regulate a multiplicity of processes including receptor-mediated endocytosis, protein degradation, fluid secretion, and neurotransmission. Composed of fourteen different subunits, several V-ATPase subunits exist in distinct isoforms to perform cell type specific functions. The 100 kD a subunit (Vha100) of V-ATPases are encoded by a family of five genes in Drosophila, but their assignments are not fully understood. Here we report an experimental survey of the Vha100 gene family during Drosophila wing development. A combination of CRISPR-Cas9 mutagenesis, somatic clonal analysis and in vivo RNAi assays is used to characterize the requirement of Vha100 isoforms, and mutants of Vha100-2, Vha100-3, Vha100-4, and Vha100-5 genes were generated. We show that Vha100-3 and Vha100-5 are dispensable for fly development, while Vha100-1 is not critically required in the wing. As for the other two isoforms, we find that Vha100-2 regulates wing cuticle maturation, while Vha100-4 is the single isoform involved in developmental patterning. More specifically, Vha100-4 is required for proper activation of the Wingless signaling pathway during fly wing development. Interestingly, we also find a specific genetic interaction between Vha100-1 and Vha100-4 during wing development. Our results revealed the distinct roles of Vha100 isoforms during insect wing development, providing a rationale for understanding the diverse roles of V-ATPases.
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Affiliation(s)
- Dongqing Mo
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Yao Chen
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Na Jiang
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Jie Shen
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Junzheng Zhang
- Department of Entomology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
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18
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Bruzzone L, Argüelles C, Sanial M, Miled S, Alvisi G, Gonçalves-Antunes M, Qasrawi F, Holmgren RA, Smibert CA, Lipshitz HD, Boccaccio GL, Plessis A, Bécam I. Regulation of the RNA-binding protein Smaug by the GPCR Smoothened via the kinase Fused. EMBO Rep 2020; 21:e48425. [PMID: 32383557 DOI: 10.15252/embr.201948425] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 03/17/2020] [Accepted: 04/14/2020] [Indexed: 12/13/2022] Open
Abstract
From fly to mammals, the Smaug/Samd4 family of prion-like RNA-binding proteins control gene expression by destabilizing and/or repressing the translation of numerous target transcripts. However, the regulation of its activity remains poorly understood. We show that Smaug's protein levels and mRNA repressive activity are downregulated by Hedgehog signaling in tissue culture cells. These effects rely on the interaction of Smaug with the G-protein coupled receptor Smoothened, which promotes the phosphorylation of Smaug by recruiting the kinase Fused. The activation of Fused and its binding to Smaug are sufficient to suppress its ability to form cytosolic bodies and to antagonize its negative effects on endogenous targets. Importantly, we demonstrate in vivo that HH reduces the levels of smaug mRNA and increases the level of several mRNAs downregulated by Smaug. Finally, we show that Smaug acts as a positive regulator of Hedgehog signaling during wing morphogenesis. These data constitute the first evidence for a post-translational regulation of Smaug and reveal that the fate of several mRNAs bound to Smaug is modulated by a major signaling pathway.
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Affiliation(s)
- Lucia Bruzzone
- CNRS, Institut Jacques Monod, Université de Paris, Paris, France
| | | | - Matthieu Sanial
- CNRS, Institut Jacques Monod, Université de Paris, Paris, France
| | - Samia Miled
- CNRS, Institut Jacques Monod, Université de Paris, Paris, France
| | - Giorgia Alvisi
- CNRS, Institut Jacques Monod, Université de Paris, Paris, France
| | | | - Fairouz Qasrawi
- CNRS, Institut Jacques Monod, Université de Paris, Paris, France
| | - Robert A Holmgren
- Department of Mol. Biosci., Northwestern University, Evanston, IL, USA
| | - Craig A Smibert
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Howard D Lipshitz
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Graciela L Boccaccio
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas Buenos Aires-Consejo Nacional de Investigaciones Científicas y Tecnológicas, Facultad de Ciencias Exactas y Naturales, University of Buenos Aires, Buenos Aires, Argentina
| | - Anne Plessis
- CNRS, Institut Jacques Monod, Université de Paris, Paris, France
| | - Isabelle Bécam
- CNRS, Institut Jacques Monod, Université de Paris, Paris, France
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19
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Abstract
Signaling pathways that mediate cell-cell communication are essential for collective cell behaviors in multicellular systems. The hedgehog (HH) pathway, first discovered and elucidated in Drosophila, is one of these iconic signaling systems that plays many roles during embryogenesis and in adults; abnormal HH signaling can lead to birth defects and cancer. We review recent structural and biochemical studies that have advanced our understanding of the vertebrate HH pathway, focusing on the mechanisms by which the HH signal is received by patched on target cells, transduced across the cell membrane by smoothened, and transmitted to the nucleus by GLI proteins to influence gene-expression programs.
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Affiliation(s)
- Jennifer H Kong
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Christian Siebold
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Rajat Rohatgi
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
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20
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Ahaley SS. Synaptojanin regulates Hedgehog signalling by modulating phosphatidylinositol 4-phosphate levels. J Biosci 2018; 43:867-876. [PMID: 30541947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In Hedgehog (Hh) signalling, Hh ligand concentration gradient is effectively translated into a spatially distinct transcriptional program to give precisely controlled context dependent developmental outcomes. In the absence of Hh, the receptor Patched (Ptc) inhibits the signal transducer Smoothened (Smo) by maintaining low phosphatidylinositol 4-phosphate (PI(4)P) levels. Binding of Hh to its receptor Ptc promotes PI(4)P production, which in turn activates Smo. Using wingdiscs of Drosophila melanogaster, this study shows that Synaptojanin (Synj), a dual phosphatase, modulates PI(4)P levels and affects Smo activation, and thereby functions as an additional regulatory step in the Hh pathway. Reducing the levels of Synj in the wing-discs caused enhancement of a Hh dominant gain-of-function Moonrat phenotype in the adult wings. Synj downregulation augmented Hh signalling, which was associated with elevated PI(4)P levels and Smo activation. Synj did not control the absolute pathway activity but rather fine-tuned the response since its downregulation increased expression of decapentaplegic (dpp), a low-threshold target of the pathway while the high-threshold targets remained unaffected. This is the first report that identifies Synj as a negative regulator of Hh signalling, implying its importance and an additional regulatory step in Hh signal transduction.
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Affiliation(s)
- Shital Sarah Ahaley
- Biology Department, Indian Institute of Science Education and Research, Pune 411 008, India,
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21
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Cheng Y, Chen D. Fruit fly research in China. J Genet Genomics 2018; 45:583-592. [PMID: 30455037 DOI: 10.1016/j.jgg.2018.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 09/21/2018] [Accepted: 09/29/2018] [Indexed: 11/19/2022]
Abstract
Served as a model organism over a century, fruit fly has significantly pushed forward the development of global scientific research, including in China. The high similarity in genomic features between fruit fly and human enables this tiny insect to benefit the biomedical studies of human diseases. In the past decades, Chinese biologists have used fruit fly to make numerous achievements on understanding the fundamental questions in many diverse areas of biology. Here, we review some of the recent fruit fly studies in China, and mainly focus on those studies in the fields of stem cell biology, cancer therapy and regeneration medicine, neurological disorders and epigenetics.
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Affiliation(s)
- Ying Cheng
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Dahua Chen
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
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22
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Liu A. Proteostasis in the Hedgehog signaling pathway. Semin Cell Dev Biol 2018; 93:153-163. [PMID: 31429406 DOI: 10.1016/j.semcdb.2018.10.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/11/2018] [Accepted: 10/22/2018] [Indexed: 12/29/2022]
Abstract
The Hedgehog (Hh) signaling pathway is crucial for the development of vertebrate and invertebrate animals alike. Hh ligand binds its receptor Patched (Ptc), allowing the activation of the obligate signal transducer Smoothened (Smo). The levels and localizations of both Ptc and Smo are regulated by ubiquitination, and Smo is under additional regulation by phosphorylation and SUMOylation. Downstream of Smo, the Ci/Gli family of transcription factors regulates the transcriptional responses to Hh. Phosphorylation, ubiquitination and SUMOylation are important for the stability and localization of Ci/Gli proteins and Hh signaling output. Finally, Suppressor of Fused directly regulates Ci/Gli proteins and itself is under proteolytic regulation that is critical for normal Hh signaling.
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Affiliation(s)
- Aimin Liu
- Department of Biology, Eberly College of Science, Huck Institute of Life Sciences, The Pennsylvania State University, University Park, PA, 16802, United States.
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23
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A genetic mosaic screen identifies genes modulating Notch signaling in Drosophila. PLoS One 2018; 13:e0203781. [PMID: 30235233 PMCID: PMC6147428 DOI: 10.1371/journal.pone.0203781] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 08/27/2018] [Indexed: 01/08/2023] Open
Abstract
Notch signaling is conserved in most multicellular organisms and plays critical roles during animal development. The core components and major signal transduction mechanism of Notch signaling have been extensively studied. However, our understanding of how Notch signaling activity is regulated in diverse developmental processes still remains incomplete. Here, we report a genetic mosaic screen in Drosophila melanogaster that leads to identification of Notch signali ng modulators during wing development. We discovered a group of genes required for the formation of the fly wing margin, a developmental process that is strictly dependent on the balanced Notch signaling activity. These genes encode transcription factors, protein phosphatases, vacuolar ATPases and factors required for RNA transport, stability, and translation. Our data support the view that Notch signaling is controlled through a wide range of molecular processes. These results also provide foundations for further study by showing that Me31B and Wdr62 function as two novel modulators of Notch signaling activity.
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24
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Synaptojanin regulates Hedgehog signalling by modulating phosphatidylinositol 4-phosphate levels. J Biosci 2018. [DOI: 10.1007/s12038-018-9799-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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25
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PpV, acting via the JNK pathway, represses apoptosis during normal development of Drosophila wing. Apoptosis 2018; 23:554-562. [DOI: 10.1007/s10495-018-1479-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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26
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Zhao L, Wang L, Chi C, Lan W, Su Y. The emerging roles of phosphatases in Hedgehog pathway. Cell Commun Signal 2017; 15:35. [PMID: 28931407 PMCID: PMC5607574 DOI: 10.1186/s12964-017-0191-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 09/14/2017] [Indexed: 01/12/2023] Open
Abstract
Hedgehog signaling is evolutionarily conserved and plays a pivotal role in cell fate determination, embryonic development, and tissue renewal. As aberrant Hedgehog signaling is tightly associated with a broad range of human diseases, its activities must be precisely controlled. It has been known that several core components of Hedgehog pathway undergo reversible phosphorylations mediated by protein kinases and phosphatases, which acts as an effective regulatory mechanism to modulate Hedgehog signal activities. In contrast to kinases that have been extensively studied in these phosphorylation events, phosphatases were thought to function in an unspecific manner, thus obtained much less emphasis in the past. However, in recent years, increasing evidence has implicated that phosphatases play crucial and specific roles in the context of developmental signaling, including Hedgehog signaling. In this review, we present a summary of current progress on phosphatase studies in Hedgehog pathway, emphasizing the multiple employments of protein serine/threonine phosphatases during the transduction of morphogenic Hedgehog signal in both Drosophila and vertebrate systems, all of which provide insights into the importance of phosphatases in the specific regulation of Hedgehog signaling.
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Affiliation(s)
- Long Zhao
- Cardiovascular Research Center, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, 02129, USA
| | - Liguo Wang
- Institute of Evolution & Marine Biodiversity, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Chunli Chi
- Institute of Evolution & Marine Biodiversity, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Wenwen Lan
- Institute of Evolution & Marine Biodiversity, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Ying Su
- Institute of Evolution & Marine Biodiversity, College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China.
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27
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Lu J, Wang D, Shen J. Hedgehog signalling is required for cell survival in Drosophila wing pouch cells. Sci Rep 2017; 7:11317. [PMID: 28900135 PMCID: PMC5595820 DOI: 10.1038/s41598-017-10550-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 08/10/2017] [Indexed: 11/09/2022] Open
Abstract
An appropriate balance between cell survival and cell death is essential for correct pattern formation in the animal tissues and organs. Previous studies have shown that the short-range signalling molecule Hedgehog (Hh) is required for cell proliferation and pattern formation in the Drosophila central wing discs. Signal transduction by one of the Hh targets, the morphogen Decapentaplegic (Dpp), is required for not only cell proliferation, but also cell survival in the pouch cells. However, Hh function in cell survival and cell death has not been revealed. Here, we found that loss of Hh signal activity induces considerable Caspase-dependent cell death in the wing pouch cells, and this process was independent of both Dpp signalling and Jun-N-terminal kinase (JNK) signalling. Loss of Hh induced activation of the pro-apoptotic gene hid and inhibition of diap1. Therefore, we identified an important role of Hh signalling in cell survival during Drosophila wing development.
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Affiliation(s)
- Juan Lu
- Department of Entomology, MOA Key Laboratory for monitoring and green management of crop pests, China Agricultural University, 100193, Beijing, China
| | - Dan Wang
- Department of Entomology, MOA Key Laboratory for monitoring and green management of crop pests, China Agricultural University, 100193, Beijing, China
| | - Jie Shen
- Department of Entomology, MOA Key Laboratory for monitoring and green management of crop pests, China Agricultural University, 100193, Beijing, China.
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28
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Du J, Zhang J, He T, Li Y, Su Y, Tie F, Liu M, Harte PJ, Zhu AJ. Stuxnet Facilitates the Degradation of Polycomb Protein during Development. Dev Cell 2017; 37:507-19. [PMID: 27326929 DOI: 10.1016/j.devcel.2016.05.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 04/29/2016] [Accepted: 05/18/2016] [Indexed: 10/21/2022]
Abstract
Polycomb-group (PcG) proteins function to ensure correct deployment of developmental programs by epigenetically repressing target gene expression. Despite the importance, few studies have been focused on the regulation of PcG activity itself. Here, we report a Drosophila gene, stuxnet (stx), that controls Pc protein stability. We find that heightened stx activity leads to homeotic transformation, reduced Pc activity, and de-repression of PcG targets. Conversely, stx mutants, which can be rescued by decreased Pc expression, display developmental defects resembling hyperactivation of Pc. Our biochemical analyses provide a mechanistic basis for the interaction between stx and Pc; Stx facilitates Pc degradation in the proteasome, independent of ubiquitin modification. Furthermore, this mode of regulation is conserved in vertebrates. Mouse stx promotes degradation of Cbx4, an orthologous Pc protein, in vertebrate cells and induces homeotic transformation in Drosophila. Our results highlight an evolutionarily conserved mechanism of regulated protein degradation on PcG homeostasis and epigenetic activity.
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Affiliation(s)
- Juan Du
- State Key Laboratory of Membrane Biology, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Junzheng Zhang
- State Key Laboratory of Membrane Biology, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Tao He
- State Key Laboratory of Membrane Biology, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China
| | - Yajuan Li
- State Key Laboratory of Membrane Biology, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China
| | - Ying Su
- State Key Laboratory of Membrane Biology, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China
| | - Feng Tie
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Min Liu
- State Key Laboratory of Membrane Biology, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Peter J Harte
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Alan Jian Zhu
- State Key Laboratory of Membrane Biology, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China.
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29
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Liu M, Li Y, Liu A, Li R, Su Y, Du J, Li C, Zhu AJ. The exon junction complex regulates the splicing of cell polarity gene dlg1 to control Wingless signaling in development. eLife 2016; 5. [PMID: 27536874 PMCID: PMC5008907 DOI: 10.7554/elife.17200] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Accepted: 08/14/2016] [Indexed: 12/22/2022] Open
Abstract
Wingless (Wg)/Wnt signaling is conserved in all metazoan animals and plays critical roles in development. The Wg/Wnt morphogen reception is essential for signal activation, whose activity is mediated through the receptor complex and a scaffold protein Dishevelled (Dsh). We report here that the exon junction complex (EJC) activity is indispensable for Wg signaling by maintaining an appropriate level of Dsh protein for Wg ligand reception in Drosophila. Transcriptome analyses in Drosophila wing imaginal discs indicate that the EJC controls the splicing of the cell polarity gene discs large 1 (dlg1), whose coding protein directly interacts with Dsh. Genetic and biochemical experiments demonstrate that Dlg1 protein acts independently from its role in cell polarity to protect Dsh protein from lysosomal degradation. More importantly, human orthologous Dlg protein is sufficient to promote Dvl protein stabilization and Wnt signaling activity, thus revealing a conserved regulatory mechanism of Wg/Wnt signaling by Dlg and EJC. DOI:http://dx.doi.org/10.7554/eLife.17200.001 Animal development involves different signaling pathways that coordinate complex behaviors of the cells, such as changes in cell number or cell shape. One such pathway involves a protein called Wingless/Wnt, which controls cell fate and growth and is also involved in tumor formation in humans. In recent decades, scientists have made a lot of progress in understanding how this signaling pathway operates. However, it is not well understood how the Wingless/Wnt signaling pathway interacts with other regulatory networks during development. Now, Liu, Li et al. unveil a new regulatory network that controls the Wingless/Wnt pathway in fruit flies and in mammalian cells grown in the laboratory. The experiments show that an RNA binding protein family named the Exon Junction Complex positively regulates a protein called Dishevelled, which serves as a hub in the Wingless/Wnt pathway. The Exon Junction Complex keeps the amount of Dishevelled protein in check via an interaction with another protein referred to as Discs large. Further experiments indicated that Discs large binds to and protects Dishevelled from being degraded inside the cell. Liu et al.'s findings highlight a new control mechanism for the Wingless/Wnt signaling pathway. In the future, the findings may also aid the development of new approaches to prevent or treat birth defects and cancer. DOI:http://dx.doi.org/10.7554/eLife.17200.002
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Affiliation(s)
- Min Liu
- State Key Laboratory of Membrane Biology and Minstry of Education Key Laboratory of Cell Proliferation and Differentiation, Peking University, Beijing, China.,School of Life Sciences, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisplinary Studies, Peking University, Beijing, China
| | - Yajuan Li
- State Key Laboratory of Membrane Biology and Minstry of Education Key Laboratory of Cell Proliferation and Differentiation, Peking University, Beijing, China.,School of Life Sciences, Peking University, Beijing, China
| | - Aiguo Liu
- State Key Laboratory of Membrane Biology and Minstry of Education Key Laboratory of Cell Proliferation and Differentiation, Peking University, Beijing, China.,School of Life Sciences, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisplinary Studies, Peking University, Beijing, China
| | - Ruifeng Li
- School of Life Sciences, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisplinary Studies, Peking University, Beijing, China.,Center for Bioinformatics, Peking University, Beijing, China.,Center for Statistical Science, Peking University, Beijing, China
| | - Ying Su
- School of Life Sciences, Peking University, Beijing, China
| | - Juan Du
- State Key Laboratory of Membrane Biology and Minstry of Education Key Laboratory of Cell Proliferation and Differentiation, Peking University, Beijing, China.,School of Life Sciences, Peking University, Beijing, China
| | - Cheng Li
- School of Life Sciences, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisplinary Studies, Peking University, Beijing, China.,Center for Bioinformatics, Peking University, Beijing, China.,Center for Statistical Science, Peking University, Beijing, China
| | - Alan Jian Zhu
- State Key Laboratory of Membrane Biology and Minstry of Education Key Laboratory of Cell Proliferation and Differentiation, Peking University, Beijing, China.,School of Life Sciences, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisplinary Studies, Peking University, Beijing, China
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30
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Klebanow LR, Peshel EC, Schuster AT, De K, Sarvepalli K, Lemieux ME, Lenoir JJ, Moore AW, McDonald JA, Longworth MS. Drosophila Condensin II subunit Chromosome-associated protein D3 regulates cell fate determination through non-cell-autonomous signaling. Development 2016; 143:2791-802. [PMID: 27317808 PMCID: PMC5004906 DOI: 10.1242/dev.133686] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 06/03/2016] [Indexed: 12/19/2022]
Abstract
The pattern of the Drosophila melanogaster adult wing is heavily influenced by the expression of proteins that dictate cell fate decisions between intervein and vein during development. dSRF (Blistered) expression in specific regions of the larval wing disc promotes intervein cell fate, whereas EGFR activity promotes vein cell fate. Here, we report that the chromatin-organizing protein CAP-D3 acts to dampen dSRF levels at the anterior/posterior boundary in the larval wing disc, promoting differentiation of cells into the anterior crossvein. CAP-D3 represses KNOT expression in cells immediately adjacent to the anterior/posterior boundary, thus blocking KNOT-mediated repression of EGFR activity and preventing cell death. Maintenance of EGFR activity in these cells depresses dSRF levels in the neighboring anterior crossvein progenitor cells, allowing them to differentiate into vein cells. These findings uncover a novel transcriptional regulatory network influencing Drosophila wing vein development, and are the first to identify a Condensin II subunit as an important regulator of EGFR activity and cell fate determination in vivo.
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Affiliation(s)
- Lindsey R Klebanow
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | - Emanuela C Peshel
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | - Andrew T Schuster
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | - Kuntal De
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | - Kavitha Sarvepalli
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | | | - Jessica J Lenoir
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA Department of Molecular Biosciences, Northwestern University, Evanston, IL 60201, USA
| | - Adrian W Moore
- Disease Mechanism Research Core, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | | | - Michelle S Longworth
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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31
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Ramsbottom SA, Pownall ME, Roelink H, Conway SJ. Regulation of Hedgehog Signalling Inside and Outside the Cell. J Dev Biol 2016; 4:23. [PMID: 27547735 PMCID: PMC4990124 DOI: 10.3390/jdb4030023] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The hedgehog (Hh) signalling pathway is conserved throughout metazoans and plays an important regulatory role in both embryonic development and adult homeostasis. Many levels of regulation exist that control the release, reception, and interpretation of the hedgehog signal. The fatty nature of the Shh ligand means that it tends to associate tightly with the cell membrane, and yet it is known to act as a morphogen that diffuses to elicit pattern formation. Heparan sulfate proteoglycans (HSPGs) play a major role in the regulation of Hh distribution outside the cell. Inside the cell, the primary cilium provides an important hub for processing the Hh signal in vertebrates. This review will summarise the current understanding of how the Hh pathway is regulated from ligand production, release, and diffusion, through to signal reception and intracellular transduction.
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Affiliation(s)
- Simon A. Ramsbottom
- Institute of Genetic Medicine, International Centre for Life, Newcastle University, NE1 3BZ Newcastle upon Tyne, UK
- Correspondence: ; Tel.: +44-(0)191-241-8612
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32
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Abstract
The Hedgehog (Hh) signalling pathway is one of the key regulators of metazoan development. Hh proteins have been shown to play roles in many developmental processes and have become paradigms for classical morphogens. Dysfunction of the Hh pathway underlies a number of human developmental abnormalities and diseases, making it an important therapeutic target. Interest in Hh signalling thus extends across many fields, from evo-devo to cancer research and regenerative medicine. Here, and in the accompanying poster, we provide an outline of the current understanding of Hh signalling mechanisms, highlighting the similarities and differences between species.
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Affiliation(s)
- Raymond Teck Ho Lee
- Developmental and Biomedical Genetics Laboratory, Institute of Molecular and Cell Biology, Agency of Science, Technology and Research (A* STAR), Singapore, 138673 Singapore
| | - Zhonghua Zhao
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 636921 Singapore
| | - Philip W Ingham
- Developmental and Biomedical Genetics Laboratory, Institute of Molecular and Cell Biology, Agency of Science, Technology and Research (A* STAR), Singapore, 138673 Singapore Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 636921 Singapore Department of Medicine, Imperial College London, London SW7 2AZ, UK
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33
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Abstract
The Hedgehog (Hh) signaling pathway play critical roles in embryonic development and adult tissue homeostasis. A critical step in Hh signal transduction is how Hh receptor Patched (Ptc) inhibits the atypical G protein-coupled receptor Smoothened (Smo) in the absence of Hh and how this inhibition is release by Hh stimulation. It is unlikely that Ptc inhibits Smo by direct interaction. Here we discuss how Hh regulates the phosphorylation and ubiquitination of Smo, leading to cell surface and ciliary accumulation of Smo in Drosophila and vertebrate cells, respectively. In addition, we discuss how PI(4)P phospholipid acts in between Ptc and Smo to regulate Smo phosphorylation and activation in response to Hh stimulation.
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Affiliation(s)
- Kai Jiang
- Markey Cancer Center, Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Jianhang Jia
- Markey Cancer Center, Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY 40536, USA
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34
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Swarup S, Pradhan-Sundd T, Verheyen EM. Genome-wide identification of phospho-regulators of Wnt signaling in Drosophila. Development 2015; 142:1502-15. [DOI: 10.1242/dev.116715] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Evolutionarily conserved intercellular signaling pathways regulate embryonic development and adult tissue homeostasis in metazoans. The precise control of the state and amplitude of signaling pathways is achieved in part through the kinase- and phosphatase-mediated reversible phosphorylation of proteins. In this study, we performed a genome-wide in vivo RNAi screen for kinases and phosphatases that regulate the Wnt pathway under physiological conditions in the Drosophila wing disc. Our analyses have identified 54 high-confidence kinases and phosphatases capable of modulating the Wnt pathway, including 22 novel regulators. These candidates were also assayed for a role in the Notch pathway, and numerous phospho-regulators were identified. Additionally, each regulator of the Wnt pathway was evaluated in the wing disc for its ability to affect the mechanistically similar Hedgehog pathway. We identified 29 dual regulators that have the same effect on the Wnt and Hedgehog pathways. As proof of principle, we established that Cdc37 and Gilgamesh/CK1γ inhibit and promote signaling, respectively, by functioning at analogous levels of these pathways in both Drosophila and mammalian cells. The Wnt and Hedgehog pathways function in tandem in multiple developmental contexts, and the identification of several shared phospho-regulators serve as potential nodes of control under conditions of aberrant signaling and disease.
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Affiliation(s)
- Sharan Swarup
- Simon Fraser University, Department of Molecular Biology and Biochemistry, Burnaby V5A1S6, British Columbia, Canada
| | - Tirthadipa Pradhan-Sundd
- Simon Fraser University, Department of Molecular Biology and Biochemistry, Burnaby V5A1S6, British Columbia, Canada
| | - Esther M. Verheyen
- Simon Fraser University, Department of Molecular Biology and Biochemistry, Burnaby V5A1S6, British Columbia, Canada
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35
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Hoffmeister M, Prelle C, Küchler P, Kovacevic I, Moser M, Müller-Esterl W, Oess S. The ubiquitin E3 ligase NOSIP modulates protein phosphatase 2A activity in craniofacial development. PLoS One 2014; 9:e116150. [PMID: 25546391 PMCID: PMC4278855 DOI: 10.1371/journal.pone.0116150] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 12/05/2014] [Indexed: 02/05/2023] Open
Abstract
Holoprosencephaly is a common developmental disorder in humans characterised by incomplete brain hemisphere separation and midface anomalies. The etiology of holoprosencephaly is heterogeneous with environmental and genetic causes, but for a majority of holoprosencephaly cases the genes associated with the pathogenesis could not be identified so far. Here we report the generation of knockout mice for the ubiquitin E3 ligase NOSIP. The loss of NOSIP in mice causes holoprosencephaly and facial anomalies including cleft lip/palate, cyclopia and facial midline clefting. By a mass spectrometry based protein interaction screen we identified NOSIP as a novel interaction partner of protein phosphatase PP2A. NOSIP mediates the monoubiquitination of the PP2A catalytic subunit and the loss of NOSIP results in an increase in PP2A activity in craniofacial tissue in NOSIP knockout mice. We conclude, that NOSIP is a critical modulator of brain and craniofacial development in mice and a candidate gene for holoprosencephaly in humans.
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Affiliation(s)
- Meike Hoffmeister
- Institute for Biochemistry II, Goethe University Frankfurt Medical School, Frankfurt/Main, Germany
| | - Carola Prelle
- Institute for Biochemistry II, Goethe University Frankfurt Medical School, Frankfurt/Main, Germany
| | - Philipp Küchler
- Institute for Biochemistry II, Goethe University Frankfurt Medical School, Frankfurt/Main, Germany
| | - Igor Kovacevic
- Institute for Biochemistry II, Goethe University Frankfurt Medical School, Frankfurt/Main, Germany
| | - Markus Moser
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Werner Müller-Esterl
- Institute for Biochemistry II, Goethe University Frankfurt Medical School, Frankfurt/Main, Germany
| | - Stefanie Oess
- Institute for Biochemistry II, Goethe University Frankfurt Medical School, Frankfurt/Main, Germany
- * E-mail:
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36
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Liu YC, Couzens AL, Deshwar AR, B McBroom-Cerajewski LD, Zhang X, Puviindran V, Scott IC, Gingras AC, Hui CC, Angers S. The PPFIA1-PP2A protein complex promotes trafficking of Kif7 to the ciliary tip and Hedgehog signaling. Sci Signal 2014; 7:ra117. [PMID: 25492966 DOI: 10.1126/scisignal.2005608] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The primary cilium is required for Hedgehog (Hh) signaling in vertebrates. Hh leads to ciliary accumulation and activation of the transmembrane protein Smoothened (Smo) and affects the localization of several pathway components, including the Gli family of transcriptional regulators, within different regions of primary cilia. Genetic analysis indicates that the kinesin protein Kif7 both promotes and inhibits mouse Hh signaling. Using mass spectrometry, we identified liprin-α1 (PPFIA1) and the protein phosphatase PP2A as Kif7-interacting proteins, and we showed that they were important for the trafficking of Kif7 and Gli proteins to the tips of cilia and for the transcriptional output of Hh signaling. Our results suggested that PPFIA1 functioned with PP2A to promote the dephosphorylation of Kif7, triggering Kif7 localization to the tips of primary cilia and promoting Gli transcriptional activity.
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Affiliation(s)
- Yulu C Liu
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Amber L Couzens
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Ashish R Deshwar
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | | | - Xiaoyun Zhang
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Vijitha Puviindran
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Ian C Scott
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada. Program in Developmental and Stem Cell Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada. Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Chi-Chung Hui
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada. Program in Developmental and Stem Cell Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Stephane Angers
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada. Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
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37
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Ranieri N, Thérond PP, Ruel L. Switch of PKA substrates from Cubitus interruptus to Smoothened in the Hedgehog signalosome complex. Nat Commun 2014; 5:5034. [PMID: 25289679 DOI: 10.1038/ncomms6034] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 08/20/2014] [Indexed: 12/20/2022] Open
Abstract
Hedgehog (Hh) signalling is crucial for developmental patterning and tissue homeostasis. In Drosophila, Hh signalling is mediated by a bifunctional transcriptional mediator, called Cubitus interruptus (Ci). Protein Kinase A (PKA)-dependent phosphorylation of the serpentine protein Smoothened (Smo) leads to Ci activation, whereas PKA-dependent phosphorylation of Ci leads to the formation of Ci repressor form. The mechanism that switches PKA from an activator to a repressor is not known. Here we show that Hh signalling activation causes PKA to switch its substrates from Ci to Smo within the Hh signalling complex (HSC). In particular, Hh signalling increases the level of Smo, which then outcompetes Ci for association with PKA and causes a switch in PKA substrate recognition. We propose a new model in which the PKA is constitutively present and active within the HSC, and in which the relative levels of Ci and Smo within the HSC determine differential activation and cellular response to Hh signalling.
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Affiliation(s)
- Nadia Ranieri
- Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK
| | - Pascal P Thérond
- 1] University Nice Sophia Antipolis, iBV, UMR 7277, 06100 Nice, France [2] CNRS, iBV, UMR 7277, Parc Valrose, 06100 Nice, France [3] INSERM, iBV, U10891, 06100 Nice, France
| | - Laurent Ruel
- 1] University Nice Sophia Antipolis, iBV, UMR 7277, 06100 Nice, France [2] CNRS, iBV, UMR 7277, Parc Valrose, 06100 Nice, France [3] INSERM, iBV, U10891, 06100 Nice, France
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38
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Huang Y, McNeil GP, Jackson FR. Translational regulation of the DOUBLETIME/CKIδ/ε kinase by LARK contributes to circadian period modulation. PLoS Genet 2014; 10:e1004536. [PMID: 25211129 PMCID: PMC4161311 DOI: 10.1371/journal.pgen.1004536] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 06/12/2014] [Indexed: 12/02/2022] Open
Abstract
The Drosophila homolog of Casein Kinase I δ/ε, DOUBLETIME (DBT), is required for Wnt, Hedgehog, Fat and Hippo signaling as well as circadian clock function. Extensive studies have established a critical role of DBT in circadian period determination. However, how DBT expression is regulated remains largely unexplored. In this study, we show that translation of dbt transcripts are directly regulated by a rhythmic RNA-binding protein (RBP) called LARK (known as RBM4 in mammals). LARK promotes translation of specific alternative dbt transcripts in clock cells, in particular the dbt-RC transcript. Translation of dbt-RC exhibits circadian changes under free-running conditions, indicative of clock regulation. Translation of a newly identified transcript, dbt-RE, is induced by light in a LARK-dependent manner and oscillates under light/dark conditions. Altered LARK abundance affects circadian period length, and this phenotype can be modified by different dbt alleles. Increased LARK delays nuclear degradation of the PERIOD (PER) clock protein at the beginning of subjective day, consistent with the known role of DBT in PER dynamics. Taken together, these data support the idea that LARK influences circadian period and perhaps responses of the clock to light via the regulated translation of DBT. Our study is the first to investigate translational control of the DBT kinase, revealing its regulation by LARK and a novel role of this RBP in Drosophila circadian period modulation. The CKI family of serine/threonine kinase regulates diverse cellular processes, through binding to and phosphorylation of a variety of protein substrates. In mammals, mutations in two members of the family, CKIε and CKIδ were found to affect circadian period length, causing phenotypes such as altered circadian period in rodents and the Familial Advanced Sleep Phase Syndrome (FASPS) in human. The Drosophila CKI δ/ε homolog DOUBLETIME (DBT) is known to have important roles in development and circadian clock function. Despite extensive studies of DBT function, little is known about how its expression is regulated. In a previous genome-wide study, we identified dbt mRNAs as potential targets of the LARK RBP. Here we describe a detailed study of the regulation of DBT expression by LARK. We found that LARK binds to and regulates translation of dbt mRNA, promoting expression of a smaller isoform; we suggest this regulatory mechanism contributes to circadian period determination. In addition, we have identified a dbt mRNA that exhibits light-induced changes in translational status, in a LARK-dependent manner. Our study is the first to analyze the translational regulation of DBT, setting the stage for similar studies in other contexts and model systems.
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Affiliation(s)
- Yanmei Huang
- Department of Neuroscience, Sackler School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Gerard P McNeil
- Department of Biology, York College, Jamaica, New York, New York, United States of America
| | - F Rob Jackson
- Department of Neuroscience, Sackler School of Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, United States of America
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39
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Maier D, Cheng S, Faubert D, Hipfner DR. A broadly conserved g-protein-coupled receptor kinase phosphorylation mechanism controls Drosophila smoothened activity. PLoS Genet 2014; 10:e1004399. [PMID: 25009998 PMCID: PMC4091690 DOI: 10.1371/journal.pgen.1004399] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 04/08/2014] [Indexed: 01/20/2023] Open
Abstract
Hedgehog (Hh) signaling is essential for normal growth, patterning, and homeostasis of many tissues in diverse organisms, and is misregulated in a variety of diseases including cancer. Cytoplasmic Hedgehog signaling is activated by multisite phosphorylation of the seven-pass transmembrane protein Smoothened (Smo) in its cytoplasmic C-terminus. Aside from a short membrane-proximal stretch, the sequence of the C-terminus is highly divergent in different phyla, and the evidence suggests that the precise mechanism of Smo activation and transduction of the signal to downstream effectors also differs. To clarify the conserved role of G-protein-coupled receptor kinases (GRKs) in Smo regulation, we mapped four clusters of phosphorylation sites in the membrane-proximal C-terminus of Drosophila Smo that are phosphorylated by Gprk2, one of the two fly GRKs. Phosphorylation at these sites enhances Smo dimerization and increases but is not essential for Smo activity. Three of these clusters overlap with regulatory phosphorylation sites in mouse Smo and are highly conserved throughout the bilaterian lineages, suggesting that they serve a common function. Consistent with this, we find that a C-terminally truncated form of Drosophila Smo consisting of just the highly conserved core, including Gprk2 regulatory sites, can recruit the downstream effector Costal-2 and activate target gene expression, in a Gprk2-dependent manner. These results indicate that GRK phosphorylation in the membrane proximal C-terminus is an evolutionarily ancient mechanism of Smo regulation, and point to a higher degree of similarity in the regulation and signaling mechanisms of bilaterian Smo proteins than has previously been recognized.
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Affiliation(s)
- Dominic Maier
- Institut de recherches cliniques de Montréal (IRCM), Montreal, Quebec, Canada
- Department of Anatomy & Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Shuofei Cheng
- Institut de recherches cliniques de Montréal (IRCM), Montreal, Quebec, Canada
- Department of Anatomy & Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Denis Faubert
- Institut de recherches cliniques de Montréal (IRCM), Montreal, Quebec, Canada
- Proteomics Core Facility, IRCM, Montreal, Quebec, Canada
| | - David R. Hipfner
- Institut de recherches cliniques de Montréal (IRCM), Montreal, Quebec, Canada
- Department of Anatomy & Cell Biology, McGill University, Montreal, Quebec, Canada
- Department of Medicine, Université de Montréal, Montreal, Quebec, Canada
- * E-mail:
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40
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Li S, Ma G, Wang B, Jiang J. Hedgehog induces formation of PKA-Smoothened complexes to promote Smoothened phosphorylation and pathway activation. Sci Signal 2014; 7:ra62. [PMID: 24985345 PMCID: PMC4621970 DOI: 10.1126/scisignal.2005414] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Hedgehog (Hh) is a secreted glycoprotein that binds its receptor Patched to activate the G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptor-like protein Smoothened (Smo). In Drosophila, protein kinase A (PKA) phosphorylates and activates Smo in cells stimulated with Hh. In unstimulated cells, PKA phosphorylates and inhibits the transcription factor Cubitus interruptus (Ci). We found that in cells exposed to Hh, the catalytic subunit of PKA (PKAc) bound to the juxtamembrane region of the carboxyl terminus of Smo. PKA-mediated phosphorylation of Smo further enhanced its association with PKAc to form stable kinase-substrate complexes that promoted the PKA-mediated transphosphorylation of Smo dimers. We identified multiple basic residues in the carboxyl terminus of Smo that were required for interaction with PKAc, Smo phosphorylation, and Hh pathway activation. Hh induced a switch from the association of PKAc with a cytosolic complex of Ci and the kinesin-like protein Costal2 (Cos2) to a membrane-bound Smo-Cos2 complex. Thus, our study uncovers a previously uncharacterized mechanism for regulation of PKA activity and demonstrates that the signal-regulated formation of kinase-substrate complexes plays a central role in Hh signal transduction.
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Affiliation(s)
- Shuang Li
- Department of Developmental Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Guoqiang Ma
- Department of Developmental Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Bing Wang
- Department of Developmental Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Jin Jiang
- Department of Developmental Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA. Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA.
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Zhang J, Du J, Lei C, Liu M, Zhu AJ. Ubpy controls the stability of the ESCRT-0 subunit Hrs in development. Development 2014; 141:1473-9. [PMID: 24574010 DOI: 10.1242/dev.099564] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Ubiquitylated developmental membrane signaling proteins are often internalized for endocytic trafficking, through which endosomal sorting complexes required for transport (ESCRT) act sequentially to deliver internalized cargos to lysosomes. The ESCRT function in endocytic sorting is well established; however, it is not fully understood how the sorting machinery itself is regulated. Here, we show that Ubiquitin isopeptidase Y (Ubpy) plays a conserved role in vivo in the homeostasis of an essential ESCRT-0 complex component Hrs. We find that, in the absence of Drosophila Ubpy, multiple membrane proteins that are essential components of important signaling pathways accumulate in enlarged, aberrant endosomes. We further demonstrate that this phenotype results from endocytic pathway defects. We provide evidence that Ubpy interacts with and deubiquitylates Hrs. In Ubpy-null cells, Hrs becomes ubiquitylated and degraded in lysosomes, thus disrupting the integrity of ESCRT sorting machinery. Lastly, we find that signaling proteins are enriched in enlarged endosomes when Hrs activity is abolished. Together, our data support a model in which Ubpy plays a dual role in both cargo deubiquitylation and the ESCRT-0 stability during development.
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Affiliation(s)
- Junzheng Zhang
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, Peking-Tsinghua Center for Life Sciences, College of Life Sciences, Peking University, Beijing 100871, China
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42
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Spratt SJ. A computation using mutually exclusive processing is sufficient to identify specific Hedgehog signaling components. Front Genet 2014; 4:284. [PMID: 24391661 PMCID: PMC3867666 DOI: 10.3389/fgene.2013.00284] [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: 07/20/2013] [Accepted: 11/26/2013] [Indexed: 11/13/2022] Open
Abstract
A system of more than one part can be deciphered by observing differences between the parts. A simple way to do this is by recording something absolute displaying a trait in one part and not in another: in other words, mutually exclusive computation. Conditional directed expression in vivo offers processing in more than one part of the system giving increased computation power for biological systems analysis. Here, I report the consideration of these aspects in the development of an in vivo screening assay that appears sufficient to identify components specific to a system.
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Affiliation(s)
- Spencer J Spratt
- Okinawa Institute of Science and Technology Graduate University Okinawa, Japan ; Department of Frontier Bioscience, Hosei University Koganei, Tokyo, Japan
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43
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Briscoe J, Thérond PP. The mechanisms of Hedgehog signalling and its roles in development and disease. Nat Rev Mol Cell Biol 2013; 14:416-29. [DOI: 10.1038/nrm3598] [Citation(s) in RCA: 1212] [Impact Index Per Article: 110.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Geisbrecht ER, Sawant K, Su Y, Liu ZC, Silver DL, Burtscher A, Wang X, Zhu AJ, McDonald JA. Genetic interaction screens identify a role for hedgehog signaling in Drosophila border cell migration. Dev Dyn 2013; 242:414-31. [PMID: 23335293 DOI: 10.1002/dvdy.23926] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 12/22/2012] [Accepted: 12/28/2012] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Cell motility is essential for embryonic development and physiological processes such as the immune response, but also contributes to pathological conditions such as tumor progression and inflammation. However, our understanding of the mechanisms underlying migratory processes is incomplete. Drosophila border cells provide a powerful genetic model to identify the roles of genes that contribute to cell migration. RESULTS Members of the Hedgehog signaling pathway were uncovered in two independent screens for interactions with the small GTPase Rac and the polarity protein Par-1 in border cell migration. Consistent with a role in migration, multiple Hh signaling components were enriched in the migratory border cells. Interference with Hh signaling by several different methods resulted in incomplete cell migration. Moreover, the polarized distribution of E-Cadherin and a marker of tyrosine kinase activity were altered when Hh signaling was disrupted. Conservation of Hh-Rac and Hh-Par-1 signaling was illustrated in the wing, in which Hh-dependent phenotypes were enhanced by loss of Rac or par-1. CONCLUSIONS We identified a pathway by which Hh signaling connects to Rac and Par-1 in cell migration. These results further highlight the importance of modifier screens in the identification of new genes that function in developmental pathways.
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Affiliation(s)
- Erika R Geisbrecht
- Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, Missouri 64110, USA
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Kupinski AP, Raabe I, Michel M, Ail D, Brusch L, Weidemann T, Bökel C. Phosphorylation of the Smo tail is controlled by membrane localization and is dispensable for clustering. J Cell Sci 2013; 126:4684-97. [DOI: 10.1242/jcs.128926] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The Hedgehog (Hh) signalling cascade is highly conserved and involved in development and disease throughout evolution. Nevertheless, in comparison with other pathways our mechanistic understanding of Hh signal transduction is remarkably incomplete. In the absence of ligand, the Hh receptor Patched (Ptc) represses the key signal transducer Smoothened (Smo) through an unknown mechanism. Hh binding to Ptc alleviates this repression, causing Smo redistribution to the plasma membrane, phosphorylation and opening of the Smo cytoplasmic tail, and Smo oligomerization. However, the order and interdependence of these events is as yet poorly understood. We have mathematically modelled and simulated Smo activation for two alternative modes of pathway activation, with Ptc primarily affecting either Smo localization or phosphorylation. Visualizing Smo activation through a novel, fluorescence based reporter allowed us to test these competing models. Here we show that Smo localization to the plasma membrane is sufficient for phosphorylation of the cytoplasmic tail in the presence of Ptc. Using fluorescence cross-correlation spectroscopy (FCCS) we furthermore demonstrate that inactivation of Ptc by Hh induces Smo clustering irrespective of Smo phosphorylation. Our observations therefore support a model of Hh signal transduction whereby Smo subcellular localization and not phosphorylation is the primary target of Ptc function.
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46
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A targeted in vivo RNAi screen reveals deubiquitinases as new regulators of Notch signaling. G3-GENES GENOMES GENETICS 2012; 2:1563-75. [PMID: 23275879 PMCID: PMC3516478 DOI: 10.1534/g3.112.003780] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 09/27/2012] [Indexed: 01/11/2023]
Abstract
Notch signaling is highly conserved in all metazoan animals and plays critical roles in cell fate specification, cell proliferation, apoptosis, and stem cell maintenance. Although core components of the Notch signaling cascade have been identified, many gaps in the understanding of the Notch signaling pathway remain to be filled. One form of posttranslational regulation, which is controlled by the ubiquitin-proteasome system, is known to modulate Notch signaling. The ubiquitination pathway is a highly coordinated process in which the ubiquitin moiety is either conjugated to or removed from target proteins by opposing E3 ubiquitin ligases and deubiquitinases (DUBs). Several E3 ubiquitin ligases have been implicated in ubiquitin conjugation to the receptors and the ligands of the Notch signaling cascade. In contrast, little is known about a direct role of DUBs in Notch signaling in vivo. Here, we report an in vivo RNA interference screen in Drosophila melanogaster targeting all 45 DUBs that we annotated in the fly genome. We show that at least four DUBs function specifically in the formation of the fly wing margin and/or the specification of the scutellar sensory organ precursors, two processes that are strictly dependent on the balanced Notch signaling activity. Furthermore, we provide genetic evidence suggesting that these DUBs are necessary to positively modulate Notch signaling activity. Our study reveals a conserved molecular mechanism by which protein deubiquitination process contributes to the complex posttranslational regulation of Notch signaling in vivo.
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Abstract
Hedgehog (Hh) proteins regulate the development of a wide range of metazoan embryonic and adult structures, and disruption of Hh signaling pathways results in various human diseases. Here, we provide a comprehensive review of the signaling pathways regulated by Hh, consolidating data from a diverse array of organisms in a variety of scientific disciplines. Similar to the elucidation of many other signaling pathways, our knowledge of Hh signaling developed in a sequential manner centered on its earliest discoveries. Thus, our knowledge of Hh signaling has for the most part focused on elucidating the mechanism by which Hh regulates the Gli family of transcription factors, the so-called "canonical" Hh signaling pathway. However, in the past few years, numerous studies have shown that Hh proteins can also signal through Gli-independent mechanisms collectively referred to as "noncanonical" signaling pathways. Noncanonical Hh signaling is itself subdivided into two distinct signaling modules: (i) those not requiring Smoothened (Smo) and (ii) those downstream of Smo that do not require Gli transcription factors. Thus, Hh signaling is now proposed to occur through a variety of distinct context-dependent signaling modules that have the ability to crosstalk with one another to form an interacting, dynamic Hh signaling network.
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Affiliation(s)
- David J Robbins
- Molecular Oncology Program, Department of Surgery, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
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Tran PV, Lachke SA, Stottmann RW. Toward a systems-level understanding of the Hedgehog signaling pathway: defining the complex, robust, and fragile. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2012; 5:83-100. [PMID: 23060005 DOI: 10.1002/wsbm.1193] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The Hedgehog (Hh) signaling pathway plays a fundamental role in development and tissue homeostasis, governing cell proliferation and differentiation, as well as cell fate. Hh signaling is mediated by an intricate network of proteins that have positive and negative roles that work in concert to fine-tune signaling output. Using feedback loops, redundancy and subcellular compartmentalization, the temporal and spatial dynamics of Hh signaling have evolved to be complex and robust. Yet developmental defects and cancers that arise from perturbation of the Hh pathway reflect specific pathway fragilities. Importantly, these fragile nodes and edges present opportunities for the design of targeted therapies. Despite these significant advances, unconnected molecular links within the Hh pathway still remain, many of which revolve around the dependence of Hh signaling on the primary cilium, an antenna-like sensory organelle. A systems-level understanding of Hh signaling and of ciliary biology will comprehensively define all nodes and edges of the Hh signaling network and will help identify precise therapeutic targets.
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Affiliation(s)
- Pamela V Tran
- Department of Anatomy and Cell Biology, The Kidney Institute, University of Kansas Medical Center, Kansas City, KS, USA.
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Wang Y, Arvanites AC, Davidow L, Blanchard J, Lam K, Yoo JW, Coy S, Rubin LL, McMahon AP. Selective identification of hedgehog pathway antagonists by direct analysis of smoothened ciliary translocation. ACS Chem Biol 2012; 7:1040-8. [PMID: 22554036 DOI: 10.1021/cb300028a] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Hedgehog (Hh) signaling promotes tumorigenesis. The accumulation of the membrane protein Smoothened (Smo) within the primary cilium (PC) is a key event in Hh signal transduction, and many pharmacological inhibitors identified to date target Smo's actions. Smo ciliary translocation is inhibited by some pathway antagonists, while others promote ciliary accumulation, an outcome that can lead to a hypersensitive state on renewal of Hh signaling. To identify novel inhibitory compounds acting on the critical mechanistic transition of Smo accumulation, we established a high content screen to directly analyze Smo ciliary translocation. Screening thousands of compounds from annotated libraries of approved drugs and other agents, we identified several new classes of compounds that block Sonic hedgehog-driven Smo localization within the PC. Selective analysis was conducted on two classes of Smo antagonists. One of these, DY131, appears to inhibit Smo signaling through a common binding site shared by previously reported Smo agonists and antagonists. Antagonism by this class of compound is competed by high doses of Smo-binding agonists such as SAG and impaired by a mutation that generates a ligand-independent, oncogenic form of Smo (SmoM2). In contrast, a second antagonist of Smo accumulation within the PC, SMANT, was less sensitive to SAG-mediated competition and inhibited SmoM2 at concentrations similar to those that inhibit wild-type Smo. Our observations identify important differences among Hh antagonists and the potential for development of novel therapeutic approaches against mutant forms of Smo that are resistant to current therapeutic strategies.
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Affiliation(s)
- Yu Wang
- Department
of Stem Cell and Regenerative Biology, ‡Department of Molecular and Cellular
Biology, §Harvard Stem Cell Institute, ∥Department of Chemistry and Chemical Biology, and ⊥Harvard College, Harvard University, Cambridge, Massachusetts
02138, United States
| | - Anthony C. Arvanites
- Department
of Stem Cell and Regenerative Biology, ‡Department of Molecular and Cellular
Biology, §Harvard Stem Cell Institute, ∥Department of Chemistry and Chemical Biology, and ⊥Harvard College, Harvard University, Cambridge, Massachusetts
02138, United States
| | - Lance Davidow
- Department
of Stem Cell and Regenerative Biology, ‡Department of Molecular and Cellular
Biology, §Harvard Stem Cell Institute, ∥Department of Chemistry and Chemical Biology, and ⊥Harvard College, Harvard University, Cambridge, Massachusetts
02138, United States
| | - Joel Blanchard
- Department
of Stem Cell and Regenerative Biology, ‡Department of Molecular and Cellular
Biology, §Harvard Stem Cell Institute, ∥Department of Chemistry and Chemical Biology, and ⊥Harvard College, Harvard University, Cambridge, Massachusetts
02138, United States
| | - Kelvin Lam
- Department
of Stem Cell and Regenerative Biology, ‡Department of Molecular and Cellular
Biology, §Harvard Stem Cell Institute, ∥Department of Chemistry and Chemical Biology, and ⊥Harvard College, Harvard University, Cambridge, Massachusetts
02138, United States
| | - Jin Woo Yoo
- Department
of Stem Cell and Regenerative Biology, ‡Department of Molecular and Cellular
Biology, §Harvard Stem Cell Institute, ∥Department of Chemistry and Chemical Biology, and ⊥Harvard College, Harvard University, Cambridge, Massachusetts
02138, United States
| | - Shannon Coy
- Department
of Stem Cell and Regenerative Biology, ‡Department of Molecular and Cellular
Biology, §Harvard Stem Cell Institute, ∥Department of Chemistry and Chemical Biology, and ⊥Harvard College, Harvard University, Cambridge, Massachusetts
02138, United States
| | - Lee L. Rubin
- Department
of Stem Cell and Regenerative Biology, ‡Department of Molecular and Cellular
Biology, §Harvard Stem Cell Institute, ∥Department of Chemistry and Chemical Biology, and ⊥Harvard College, Harvard University, Cambridge, Massachusetts
02138, United States
| | - Andrew P. McMahon
- Department
of Stem Cell and Regenerative Biology, ‡Department of Molecular and Cellular
Biology, §Harvard Stem Cell Institute, ∥Department of Chemistry and Chemical Biology, and ⊥Harvard College, Harvard University, Cambridge, Massachusetts
02138, United States
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50
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Wang N, Leung HT, Mazalouskas MD, Watkins GR, Gomez RJ, Wadzinski BE. Essential roles of the Tap42-regulated protein phosphatase 2A (PP2A) family in wing imaginal disc development of Drosophila melanogaster. PLoS One 2012; 7:e38569. [PMID: 22701670 PMCID: PMC3368869 DOI: 10.1371/journal.pone.0038569] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 05/07/2012] [Indexed: 11/18/2022] Open
Abstract
Protein ser/thr phosphatase 2A family members (PP2A, PP4, and PP6) are implicated in the control of numerous biological processes, but our understanding of the in vivo function and regulation of these enzymes is limited. In this study, we investigated the role of Tap42, a common regulatory subunit for all three PP2A family members, in the development of Drosophila melanogaster wing imaginal discs. RNAi-mediated silencing of Tap42 using the binary Gal4/UAS system and two disc drivers, pnr- and ap-Gal4, not only decreased survival rates but also hampered the development of wing discs, resulting in a remarkable thorax cleft and defective wings in adults. Silencing of Tap42 also altered multiple signaling pathways (HH, JNK and DPP) and triggered apoptosis in wing imaginal discs. The Tap42RNAi-induced defects were the direct result of loss of regulation of Drosophila PP2A family members (MTS, PP4, and PPV), as enforced expression of wild type Tap42, but not a phosphatase binding defective Tap42 mutant, rescued fly survivorship and defects. The experimental platform described herein identifies crucial roles for Tap42•phosphatase complexes in governing imaginal disc and fly development.
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Affiliation(s)
- Ning Wang
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Hung-Tat Leung
- Department of Biological Sciences, Grambling State University, Grambling, Louisiana, United States of America
| | - Matthew D. Mazalouskas
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Guy R. Watkins
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Rey J. Gomez
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Brian E. Wadzinski
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- * E-mail:
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