1
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Baran B, Derua R, Janssens V, Niewiadomski P. PP2A phosphatase regulatory subunit PPP2R3C is a new positive regulator of the hedgehog signaling pathway. Cell Signal 2024; 123:111352. [PMID: 39173855 DOI: 10.1016/j.cellsig.2024.111352] [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: 02/25/2024] [Revised: 08/16/2024] [Accepted: 08/17/2024] [Indexed: 08/24/2024]
Abstract
Cellular signaling pathways rely on posttranslational modifications (PTMs) to finely regulate protein functions, particularly transcription factors. The Hedgehog (Hh) signaling cascade, crucial for embryonic development and tissue homeostasis, is susceptible to aberrations that lead to developmental anomalies and various cancers. At the core of Hh signaling are Gli proteins, whose dynamic balance between activator (GliA) and repressor (GliR) states shapes cellular outcomes. Phosphorylation, orchestrated by multiple kinases, is pivotal in regulating Gli activity. While kinases in this context have been extensively studied, the role of protein phosphatases, particularly Protein Phosphatase 2A (PP2A), remains less explored. This study unveils a novel role for the B″gamma subunit of PP2A, PPP2R3C, in Hh signaling regulation. PPP2R3C interacts with Gli proteins, and its disruption reduces Hedgehog pathway activity as measured by reduced expression of Gli1/2 and Hh target genes upon Hh signaling activation, and reduced growth of a Hh signaling-dependent medulloblastoma cell line. Moreover, we establish an antagonistic connection between PPP2R3C and MEKK1 kinase in Gli protein phosphorylation, underscoring the intricate interplay between kinases and phosphatases in Hh signaling pathway. This study sheds light on the previously understudied role of protein phosphatases in Hh signaling and provides insights into their significance in cellular regulation.
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Affiliation(s)
- Brygida Baran
- Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland; Faculty of Biology, University of Warsaw, 02-089 Warsaw, Poland.
| | - Rita Derua
- Laboratory of Protein Phosphorylation & Proteomics, Department of Cellular & Molecular Medicine, University of Leuven (KU Leuven), B-3000 Leuven, Belgium
| | - Veerle Janssens
- Laboratory of Protein Phosphorylation & Proteomics, Department of Cellular & Molecular Medicine, University of Leuven (KU Leuven), B-3000 Leuven, Belgium
| | - Paweł Niewiadomski
- Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland.
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2
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Hwang H, Chen S, Ma M, Divyanshi, Fan HC, Borwick E, Böke E, Mei W, Yang J. Solubility phase transition of maternal RNAs during vertebrate oocyte-to-embryo transition. Dev Cell 2023; 58:2776-2788.e5. [PMID: 37922909 PMCID: PMC10841985 DOI: 10.1016/j.devcel.2023.10.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 07/01/2023] [Accepted: 10/11/2023] [Indexed: 11/07/2023]
Abstract
The oocyte-to-embryo transition (OET) is regulated by maternal products stored in the oocyte cytoplasm, independent of transcription. How maternal products are precisely remodeled to dictate the OET remains largely unclear. In this work, we discover the dynamic solubility phase transition of maternal RNAs during Xenopus OET. We have identified 863 maternal transcripts that transition from a soluble state to a detergent-insoluble one after oocyte maturation. These RNAs are enriched in the animal hemisphere, and many of them encode key cell cycle regulators. In contrast, 165 transcripts, including nearly all Xenopus germline RNAs and some vegetally localized somatic RNAs, undergo an insoluble-to-soluble phase transition. This phenomenon is conserved in zebrafish. Our results demonstrate that the phase transition of germline RNAs influences their susceptibility to RNA degradation machinery and is mediated by the remodeling of germ plasm. This work thus identifies important remodeling mechanisms that act on RNAs to control vertebrate OET.
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Affiliation(s)
- Hyojeong Hwang
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, IL 61802, USA
| | - Sijie Chen
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, IL 61802, USA
| | - Meng Ma
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, IL 61802, USA
| | - Divyanshi
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, IL 61801, USA
| | - Hao-Chun Fan
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, IL 61802, USA
| | - Elizabeth Borwick
- School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, IL 61801, USA
| | - Elvan Böke
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Wenyan Mei
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, IL 61802, USA
| | - Jing Yang
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, IL 61802, USA
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, IL 61801, USA
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3
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Peris I, Romero-Murillo S, Vicente C, Narla G, Odero MD. Regulation and role of the PP2A-B56 holoenzyme family in cancer. Biochim Biophys Acta Rev Cancer 2023; 1878:188953. [PMID: 37437699 DOI: 10.1016/j.bbcan.2023.188953] [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: 05/14/2023] [Revised: 07/07/2023] [Accepted: 07/08/2023] [Indexed: 07/14/2023]
Abstract
Protein phosphatase 2A (PP2A) inactivation is common in cancer, leading to sustained activation of pro-survival and growth-promoting pathways. PP2A consists of a scaffolding A-subunit, a catalytic C-subunit, and a regulatory B-subunit. The functional complexity of PP2A holoenzymes arises mainly through the vast repertoire of regulatory B-subunits, which determine both their substrate specificity and their subcellular localization. Therefore, a major challenge for developing more effective therapeutic strategies for cancer is to identify the specific PP2A complexes to be targeted. Of note, the development of small molecules specifically directed at PP2A-B56α has opened new therapeutic avenues in both solid and hematological tumors. Here, we focus on the B56/PR61 family of PP2A regulatory subunits, which have a central role in directing PP2A tumor suppressor activity. We provide an overview of the mechanisms controlling the formation and regulation of these complexes, the pathways they control, and the mechanisms underlying their deregulation in cancer.
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Affiliation(s)
- Irene Peris
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain; Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain; Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain.
| | - Silvia Romero-Murillo
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain; Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain
| | - Carmen Vicente
- Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain; Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Goutham Narla
- Division of Genetic Medicine, Department of Internal Medicine, The University of Michigan Medical School, Ann Arbor, MI, USA
| | - Maria D Odero
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain; Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain; Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain; CIBERONC, Instituto de Salud Carlos III, Madrid, Spain.
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4
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Hwang H, Chen S, Ma M, Divyanshi, Fan HC, Borwick E, Böke E, Mei W, Yang J. Phase transition of maternal RNAs during vertebrate oocyte-to-embryo transition. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.11.540463. [PMID: 37214813 PMCID: PMC10197690 DOI: 10.1101/2023.05.11.540463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The oocyte-to-embryo transition (OET) is regulated by maternal products stored in the oocyte cytoplasm, independent of transcription. How maternal products are precisely remodeled to dictate the OET remains an open question. In this work, we discover the dynamic phase transition of maternal RNAs during Xenopus OET. We have identified 863 maternal transcripts that transition from a soluble state to a detergent-insoluble one after oocyte maturation. These RNAs are enriched in the animal hemisphere and many of them encode key cell cycle regulators. In contrast, 165 transcripts, including nearly all Xenopus germline RNAs and some vegetally localized somatic RNAs, undergo an insoluble-to-soluble phase transition. This phenomenon is conserved in zebrafish. Our results demonstrate that the phase transition of germline RNAs influences their susceptibility to RNA degradation machinery and is mediated by the remodeling of germ plasm. This work thus uncovers novel remodeling mechanisms that act on RNAs to regulate vertebrate OET.
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Affiliation(s)
- Hyojeong Hwang
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, IL 61802, USA
| | - Sijie Chen
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, IL 61802, USA
| | - Meng Ma
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, IL 61802, USA
| | - Divyanshi
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, IL 61801, USA
| | - Hao-Chun Fan
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, IL 61802, USA
| | - Elizabeth Borwick
- School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, IL 61801, USA
| | - Elvan Böke
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Wenyan Mei
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, IL 61802, USA
| | - Jing Yang
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, IL 61802, USA
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, IL 61801, USA
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5
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Diacou R, Nandigrami P, Fiser A, Liu W, Ashery-Padan R, Cvekl A. Cell fate decisions, transcription factors and signaling during early retinal development. Prog Retin Eye Res 2022; 91:101093. [PMID: 35817658 PMCID: PMC9669153 DOI: 10.1016/j.preteyeres.2022.101093] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 06/02/2022] [Accepted: 06/03/2022] [Indexed: 12/30/2022]
Abstract
The development of the vertebrate eyes is a complex process starting from anterior-posterior and dorso-ventral patterning of the anterior neural tube, resulting in the formation of the eye field. Symmetrical separation of the eye field at the anterior neural plate is followed by two symmetrical evaginations to generate a pair of optic vesicles. Next, reciprocal invagination of the optic vesicles with surface ectoderm-derived lens placodes generates double-layered optic cups. The inner and outer layers of the optic cups develop into the neural retina and retinal pigment epithelium (RPE), respectively. In vitro produced retinal tissues, called retinal organoids, are formed from human pluripotent stem cells, mimicking major steps of retinal differentiation in vivo. This review article summarizes recent progress in our understanding of early eye development, focusing on the formation the eye field, optic vesicles, and early optic cups. Recent single-cell transcriptomic studies are integrated with classical in vivo genetic and functional studies to uncover a range of cellular mechanisms underlying early eye development. The functions of signal transduction pathways and lineage-specific DNA-binding transcription factors are dissected to explain cell-specific regulatory mechanisms underlying cell fate determination during early eye development. The functions of homeodomain (HD) transcription factors Otx2, Pax6, Lhx2, Six3 and Six6, which are required for early eye development, are discussed in detail. Comprehensive understanding of the mechanisms of early eye development provides insight into the molecular and cellular basis of developmental ocular anomalies, such as optic cup coloboma. Lastly, modeling human development and inherited retinal diseases using stem cell-derived retinal organoids generates opportunities to discover novel therapies for retinal diseases.
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Affiliation(s)
- Raven Diacou
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Prithviraj Nandigrami
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Andras Fiser
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Wei Liu
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Ruth Ashery-Padan
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Ales Cvekl
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
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6
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Paganos P, Ullrich-Lüter E, Caccavale F, Zakrzewski A, Voronov D, Fournon-Berodia I, Cocurullo M, Lüter C, Arnone MI. A New Model Organism to Investigate Extraocular Photoreception: Opsin and Retinal Gene Expression in the Sea Urchin Paracentrotus lividus. Cells 2022; 11:2636. [PMID: 36078045 PMCID: PMC9454927 DOI: 10.3390/cells11172636] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/17/2022] [Accepted: 08/18/2022] [Indexed: 11/16/2022] Open
Abstract
Molecular research on the evolution of extraocular photoreception has drawn attention to photosensitive animals lacking proper eye organs. Outside of vertebrates, little is known about this type of sensory system in any other deuterostome. In this study, we investigate such an extraocular photoreceptor cell (PRC) system in developmental stages of the sea urchin Paracentrotus lividus. We provide a general overview of the cell type families present at the mature rudiment stage using single-cell transcriptomics, while emphasizing the PRCs complexity. We show that three neuronal and one muscle-like PRC type families express retinal genes prior to metamorphosis. Two of the three neuronal PRC type families express a rhabdomeric opsin as well as an echinoderm-specific opsin (echinopsin), and their genetic wiring includes sea urchin orthologs of key retinal genes such as hlf, pp2ab56e, barh, otx, ac/sc, brn3, six1/2, pax6, six3, neuroD, irxA, isl and ato. Using qPCR, in situ hybridization, and immunohistochemical analysis, we found that the expressed retinal gene composition becomes more complex from mature rudiment to juvenile stage. The majority of retinal genes are expressed dominantly in the animals' podia, and in addition to the genes already expressed in the mature rudiment, the juvenile podia express a ciliary opsin, another echinopsin, and two Go-opsins. The expression of a core of vertebrate retinal gene orthologs indicates that sea urchins have an evolutionarily conserved gene regulatory toolkit that controls photoreceptor specification and function, and that their podia are photosensory organs.
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Affiliation(s)
- Periklis Paganos
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy
| | - Esther Ullrich-Lüter
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, 10115 Berlin, Germany
| | - Filomena Caccavale
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy
| | - Anne Zakrzewski
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, 10115 Berlin, Germany
| | - Danila Voronov
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy
| | - Inés Fournon-Berodia
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy
| | - Maria Cocurullo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy
| | - Carsten Lüter
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, 10115 Berlin, Germany
| | - Maria Ina Arnone
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy
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7
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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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Sandal P, Jong CJ, Merrill RA, Song J, Strack S. Protein phosphatase 2A - structure, function and role in neurodevelopmental disorders. J Cell Sci 2021; 134:270819. [PMID: 34228795 DOI: 10.1242/jcs.248187] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Neurodevelopmental disorders (NDDs), including intellectual disability (ID), autism and schizophrenia, have high socioeconomic impact, yet poorly understood etiologies. A recent surge of large-scale genome or exome sequencing studies has identified a multitude of mostly de novo mutations in subunits of the protein phosphatase 2A (PP2A) holoenzyme that are strongly associated with NDDs. PP2A is responsible for at least 50% of total Ser/Thr dephosphorylation in most cell types and is predominantly found as trimeric holoenzymes composed of catalytic (C), scaffolding (A) and variable regulatory (B) subunits. PP2A can exist in nearly 100 different subunit combinations in mammalian cells, dictating distinct localizations, substrates and regulatory mechanisms. PP2A is well established as a regulator of cell division, growth, and differentiation, and the roles of PP2A in cancer and various neurodegenerative disorders, such as Alzheimer's disease, have been reviewed in detail. This Review summarizes and discusses recent reports on NDDs associated with mutations of PP2A subunits and PP2A-associated proteins. We also discuss the potential impact of these mutations on the structure and function of the PP2A holoenzymes and the etiology of NDDs.
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Affiliation(s)
- Priyanka Sandal
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Chian Ju Jong
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Ronald A Merrill
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Jianing Song
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Stefan Strack
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
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9
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Optogenetic Control of the Canonical Wnt Signaling Pathway During Xenopus laevis Embryonic Development. J Mol Biol 2021; 433:167050. [PMID: 34019868 DOI: 10.1016/j.jmb.2021.167050] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 12/21/2022]
Abstract
Optogenetics uses light-inducible protein-protein interactions to precisely control the timing, localization, and intensity of signaling activity. The precise spatial and temporal resolution of this emerging technology has proven extremely attractive to the study of embryonic development, a program faithfully replicated to form the same organism from a single cell. We have previously performed a comparative study for optogenetic activation of receptor tyrosine kinases, where we found that the cytoplasm-to-membrane translocation-based optogenetic systems outperform the membrane-anchored dimerization systems in activating the receptor tyrosine kinase signaling in live Xenopus embryos. Here, we determine if this engineering strategy can be generalized to other signaling pathways involving membrane-bound receptors. As a proof of concept, we demonstrate that the cytoplasm-to-membrane translocation of the low-density lipoprotein receptor-related protein-6 (LRP6), a membrane-bound coreceptor for the canonical Wnt pathway, triggers Wnt activity. Optogenetic activation of LRP6 leads to axis duplication in developing Xenopus embryos, indicating that the cytoplasm-to-membrane translocation of the membrane-bound receptor could be a generalizable strategy for the construction of optogenetic systems.
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Chichagova V, Hilgen G, Ghareeb A, Georgiou M, Carter M, Sernagor E, Lako M, Armstrong L. Human iPSC differentiation to retinal organoids in response to IGF1 and BMP4 activation is line- and method-dependent. Stem Cells 2019; 38:195-201. [PMID: 31721366 PMCID: PMC7383896 DOI: 10.1002/stem.3116] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 10/09/2019] [Indexed: 12/13/2022]
Abstract
Induced pluripotent stem cell (iPSC)‐derived retinal organoids provide a platform to study human retinogenesis, disease modeling, and compound screening. Although retinal organoids may represent tissue structures with greater physiological relevance to the in vivo human retina, their generation is not without limitations. Various protocols have been developed to enable development of organoids with all major retinal cell types; however, variability across iPSC lines is often reported. Modulating signaling pathways important for eye formation, such as those involving bone morphogenetic protein 4 (BMP4) and insulin‐like growth factor 1 (IGF1), is a common approach used for the generation of retinal tissue in vitro. We used three human iPSC lines to generate retinal organoids by activating either BMP4 or IGF1 signaling and assessed differentiation efficiency by monitoring morphological changes, gene and protein expression, and function. Our results showed that the ability of iPSC to give rise to retinal organoids in response to IGF1 and BMP4 activation was line‐ and method‐dependent. This demonstrates that careful consideration is needed when choosing a differentiation approach, which would also depend on overall project aims.
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Affiliation(s)
| | - Gerrit Hilgen
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Ali Ghareeb
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Maria Georgiou
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Madeleine Carter
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Evelyne Sernagor
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Majlinda Lako
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Lyle Armstrong
- Newcells Biotech Ltd, Newcastle upon Tyne, UK.,Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
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11
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Hwang H, Jin Z, Krishnamurthy VV, Saha A, Klein PS, Garcia B, Mei W, King ML, Zhang K, Yang J. Novel functions of the ubiquitin-independent proteasome system in regulating Xenopus germline development. Development 2019; 146:dev172700. [PMID: 30910828 PMCID: PMC6503979 DOI: 10.1242/dev.172700] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 03/20/2019] [Indexed: 01/22/2023]
Abstract
In most species, early germline development occurs in the absence of transcription with germline determinants subject to complex translational and post-translational regulations. Here, we report for the first time that early germline development is influenced by dynamic regulation of the proteasome system, previously thought to be ubiquitously expressed and to serve 'housekeeping' roles in controlling protein homeostasis. We show that proteasomes are present in a gradient with the highest levels in the animal hemisphere and extending into the vegetal hemisphere of Xenopus oocytes. This distribution changes dramatically during the oocyte-to-embryo transition, with proteasomes becoming enriched in and restricted to the animal hemisphere and therefore separated from vegetally localized germline determinants. We identify Dead-end1 (Dnd1), a master regulator of vertebrate germline development, as a novel substrate of the ubiquitin-independent proteasomes. In the oocyte, ubiquitin-independent proteasomal degradation acts together with translational repression to prevent premature accumulation of Dnd1 protein. In the embryo, artificially increasing ubiquitin-independent proteasomal degradation in the vegetal pole interferes with germline development. Our work thus reveals novel inhibitory functions and spatial regulation of the ubiquitin-independent proteasome during vertebrate germline development.
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Affiliation(s)
- Hyojeong Hwang
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, 3411 Veterinary Medicine Basic Sciences Building, Urbana, IL 61802, USA
| | - Zhigang Jin
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, 3411 Veterinary Medicine Basic Sciences Building, Urbana, IL 61802, USA
- College of Chemistry and Life Sciences, Zhejiang Normal University, 688 Yingbin Road, Jinhua, Zhejiang 321004, China
| | - Vishnu Vardhan Krishnamurthy
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S Mathews, 314B Roger Adams Laboratory, Urbana, IL 61801, USA
| | - Anumita Saha
- Epigenetics Institute, Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA 19104, USA
| | - Peter S Klein
- Department of Medicine (Hematology-Oncology), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Benjamin Garcia
- Epigenetics Institute, Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, 3400 Civic Center Blvd, Philadelphia, PA 19104, USA
| | - Wenyan Mei
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, 3411 Veterinary Medicine Basic Sciences Building, Urbana, IL 61802, USA
| | - Mary Lou King
- Department of Cell Biology, University of Miami Miller School of Medicine, 1011 NW 15th St, Miami, FL 33136, USA
| | - Kai Zhang
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S Mathews, 314B Roger Adams Laboratory, Urbana, IL 61801, USA
| | - Jing Yang
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, 3411 Veterinary Medicine Basic Sciences Building, Urbana, IL 61802, USA
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12
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Momplaisir N, Turgeon A, Flaws J, Yang J. The Effect of an Environmentally Relevant Phthalate Mixture on Primordial Germ Cells of Xenopus laevis Embryos. MICROPUBLICATION BIOLOGY 2018; 2018. [PMID: 32550375 PMCID: PMC7255810 DOI: 10.17912/micropub.biology.000080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - Aurora Turgeon
- University of Illinois at Urbana-Champaign, Urbana-Champaign, IL, 61802
| | - Jodi Flaws
- University of Illinois at Urbana-Champaign, Urbana-Champaign, IL, 61802
| | - Jing Yang
- University of Illinois at Urbana-Champaign, Urbana-Champaign, IL, 61802
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13
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Cerrizuela S, Vega-López GA, Palacio MB, Tríbulo C, Aybar MJ. Gli2 is required for the induction and migration of Xenopus laevis neural crest. Mech Dev 2018; 154:219-239. [PMID: 30086335 DOI: 10.1016/j.mod.2018.07.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 07/09/2018] [Accepted: 07/26/2018] [Indexed: 01/22/2023]
Abstract
The neural crest (NC) is a multipotent migratory embryonic population that is formed during late gastrulation and gives rise to a wide array of derivatives, including cells from the peripheral nervous system (PNS), the craniofacial bones and cartilages, peripheral glial cells, and melanocyte cells, among others. In this work we analyzed the role of the Hedgehog signaling pathway effector gli2 in Xenopus NC. We provide evidence that the gli2 gene is expressed in the prospective, premigratory and migratory NC. The use of a specific morpholino against gli2 and the pharmacological specific inhibitor GANT61 in different experimental approaches allowed us to determine that gli2 is required for the induction and specification of NC cells as a transcriptional activator. Moreover, gli2 also acts by reducing apoptosis in the NC without affecting its cell proliferation status. We also demonstrated that gli2 is required cell-autonomously for NC migration, and for the formation of NC derivatives such as the craniofacial cartilages, melanocytes and the cranial ganglia. Altogether, our results showed that gli2 is a key transcriptional activator to accomplish the proper specification and development of Xenopus NC cells.
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Affiliation(s)
- Santiago Cerrizuela
- Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT), San Miguel de Tucumán, Argentina.
| | - Guillermo A Vega-López
- Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT), San Miguel de Tucumán, Argentina; Instituto de Biología "Dr. Francisco D. Barbieri", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Miguel de Tucumán, Argentina.
| | - María Belén Palacio
- Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT), San Miguel de Tucumán, Argentina
| | - Celeste Tríbulo
- Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT), San Miguel de Tucumán, Argentina; Instituto de Biología "Dr. Francisco D. Barbieri", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Miguel de Tucumán, Argentina.
| | - Manuel J Aybar
- Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT), San Miguel de Tucumán, Argentina; Instituto de Biología "Dr. Francisco D. Barbieri", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Miguel de Tucumán, Argentina.
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14
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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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15
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Krishnamurthy VV, Khamo JS, Mei W, Turgeon AJ, Ashraf HM, Mondal P, Patel DB, Risner N, Cho EE, Yang J, Zhang K. Reversible optogenetic control of kinase activity during differentiation and embryonic development. Development 2016; 143:4085-4094. [PMID: 27697903 DOI: 10.1242/dev.140889] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 09/19/2016] [Indexed: 12/16/2022]
Abstract
A limited number of signaling pathways are repeatedly used to regulate a wide variety of processes during development and differentiation. The lack of tools to manipulate signaling pathways dynamically in space and time has been a major technical challenge for biologists. Optogenetic techniques, which utilize light to control protein functions in a reversible fashion, hold promise for modulating intracellular signaling networks with high spatial and temporal resolution. Applications of optogenetics in multicellular organisms, however, have not been widely reported. Here, we create an optimized bicistronic optogenetic system using Arabidopsis thaliana cryptochrome 2 (CRY2) protein and the N-terminal domain of cryptochrome-interacting basic-helix-loop-helix (CIBN). In a proof-of-principle study, we develop an optogenetic Raf kinase that allows reversible light-controlled activation of the Raf/MEK/ERK signaling cascade. In PC12 cells, this system significantly improves light-induced cell differentiation compared with co-transfection. When applied to Xenopus embryos, this system enables blue light-dependent reversible Raf activation at any desired developmental stage in specific cell lineages. Our system offers a powerful optogenetic tool suitable for manipulation of signaling pathways with high spatial and temporal resolution in a wide range of experimental settings.
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Affiliation(s)
- Vishnu V Krishnamurthy
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - John S Khamo
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Wenyan Mei
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
| | - Aurora J Turgeon
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
| | - Humza M Ashraf
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Payel Mondal
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Dil B Patel
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Noah Risner
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Ellen E Cho
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Jing Yang
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
| | - Kai Zhang
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA .,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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16
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Jin Z, Schwend T, Fu J, Bao Z, Liang J, Zhao H, Mei W, Yang J. Members of the Rusc protein family interact with Sufu and inhibit vertebrate Hedgehog signaling. Development 2016; 143:3944-3955. [PMID: 27633991 DOI: 10.1242/dev.138917] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 09/01/2016] [Indexed: 12/20/2022]
Abstract
Hedgehog (Hh) signaling is fundamentally important for development and adult tissue homeostasis. It is well established that in vertebrates Sufu directly binds and inhibits Gli proteins, the downstream mediators of Hh signaling. However, it is unclear how the inhibitory function of Sufu towards Gli is regulated. Here we report that the Rusc family of proteins, the biological functions of which are poorly understood, form a heterotrimeric complex with Sufu and Gli. Upon Hh signaling, Rusc is displaced from this complex, followed by dissociation of Gli from Sufu. In mammalian fibroblast cells, knockdown of Rusc2 potentiates Hh signaling by accelerating signaling-induced dissociation of the Sufu-Gli protein complexes. In Xenopus embryos, knockdown of Rusc1 or overexpression of a dominant-negative Rusc enhances Hh signaling during eye development, leading to severe eye defects. Our study thus uncovers a novel regulatory mechanism controlling the response of cells to Hh signaling in vertebrates.
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Affiliation(s)
- Zhigang Jin
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, 2001 S Lincoln Avenue, Urbana, IL 61802, USA
| | - Tyler Schwend
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, 2001 S Lincoln Avenue, Urbana, IL 61802, USA
| | - Jia Fu
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, 2001 S Lincoln Avenue, Urbana, IL 61802, USA
| | - Zehua Bao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA
| | - Jing Liang
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA
| | - Wenyan Mei
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, 2001 S Lincoln Avenue, Urbana, IL 61802, USA
| | - Jing Yang
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, 2001 S Lincoln Avenue, Urbana, IL 61802, USA
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17
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Arriazu E, Pippa R, Odero MD. Protein Phosphatase 2A as a Therapeutic Target in Acute Myeloid Leukemia. Front Oncol 2016; 6:78. [PMID: 27092295 PMCID: PMC4822158 DOI: 10.3389/fonc.2016.00078] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 03/21/2016] [Indexed: 12/31/2022] Open
Abstract
Acute myeloid leukemia (AML) is a heterogeneous malignant disorder of hematopoietic progenitor cells in which several genetic and epigenetic aberrations have been described. Despite progressive advances in our understanding of the molecular biology of this disease, the outcome for most patients is poor. It is, therefore, necessary to develop more effective treatment strategies. Genetic aberrations affecting kinases have been widely studied in AML; however, the role of phosphatases remains underexplored. Inactivation of the tumor-suppressor protein phosphatase 2A (PP2A) is frequent in AML patients, making it a promising target for therapy. There are several PP2A inactivating mechanisms reported in this disease. Deregulation or specific post-translational modifications of PP2A subunits have been identified as a cause of PP2A malfunction, which lead to deregulation of proliferation or apoptosis pathways, depending on the subunit affected. Likewise, overexpression of either SET or cancerous inhibitor of protein phosphatase 2A, endogenous inhibitors of PP2A, is a recurrent event in AML that impairs PP2A activity, contributing to leukemogenesis progression. Interestingly, the anticancer activity of several PP2A-activating drugs (PADs) depends on interaction/sequestration of SET. Preclinical studies show that pharmacological restoration of PP2A activity by PADs effectively antagonizes leukemogenesis, and that these drugs have synergistic cytotoxic effects with conventional chemotherapy and kinase inhibitors, opening new possibilities for personalized treatment in AML patients, especially in cases with SET-dependent inactivation of PP2A. Here, we review the role of PP2A as a druggable tumor suppressor in AML.
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Affiliation(s)
- Elena Arriazu
- Hematology/Oncology Program, Center for Applied Medical Research (CIMA), University of Navarra , Pamplona , Spain
| | - Raffaella Pippa
- Centre for Gene Regulation and Expression, University of Dundee , Dundee , UK
| | - María D Odero
- Hematology/Oncology Program, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain; Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain; Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
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18
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Luehders K, Sasai N, Davaapil H, Kurosawa-Yoshida M, Hiura H, Brah T, Ohnuma SI. The small leucine-rich repeat secreted protein Asporin induces eyes in Xenopus embryos through the IGF signalling pathway. Development 2016; 142:3351-61. [PMID: 26443635 DOI: 10.1242/dev.124438] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Small leucine-rich repeat proteoglycan (SLRP) family proteins play important roles in a number of biological events. Here, we demonstrate that the SLRP family member Asporin (ASPN) plays a crucial role in the early stages of eye development in Xenopus embryos. During embryogenesis, ASPN is broadly expressed in the neuroectoderm of the embryo. Overexpression of ASPN causes the induction of ectopic eyes. By contrast, blocking ASPN function with a morpholino oligonucleotide (ASPN-MO) inhibits eye formation, indicating that ASPN is an essential factor for eye development. Detailed molecular analyses revealed that ASPN interacts with insulin growth factor receptor (IGFR) and is essential for activating the IGF receptor-mediated intracellular signalling pathway. Moreover, ASPN perturbed the Wnt, BMP and Activin signalling pathways, suggesting that ASPN thereby creates a favourable environment in which the IGF signal can dominate. ASPN is thus a novel secreted molecule essential for eye induction through the coordination of multiple signalling pathways.
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Affiliation(s)
- Kristin Luehders
- Ocular Biology and Therapeutic unit (ORBIT), Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Noriaki Sasai
- Ocular Biology and Therapeutic unit (ORBIT), Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK Developmental Biomedical Science, Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), 8916-5, Takayama-cho, Ikoma 630-0192, Japan
| | - Hongorzul Davaapil
- Ocular Biology and Therapeutic unit (ORBIT), Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Maiko Kurosawa-Yoshida
- Department of Oncology, The Hutchison/MRC Research Centre, University of Cambridge, Hills Road, Cambridge CB2 2XZ, UK
| | - Hitoshi Hiura
- Ocular Biology and Therapeutic unit (ORBIT), Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Tara Brah
- Ocular Biology and Therapeutic unit (ORBIT), Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Shin-ichi Ohnuma
- Ocular Biology and Therapeutic unit (ORBIT), Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK Department of Oncology, The Hutchison/MRC Research Centre, University of Cambridge, Hills Road, Cambridge CB2 2XZ, UK
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19
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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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20
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Qureshi O, Cho H, Choudhary M, Seeling JM. A Nonsynonymous/Synonymous Substitution Analysis of the B56 Gene Family Aids in Understanding B56 Isoform Diversity. PLoS One 2015; 10:e0145529. [PMID: 26692027 PMCID: PMC4687035 DOI: 10.1371/journal.pone.0145529] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 12/04/2015] [Indexed: 11/18/2022] Open
Abstract
Gene duplication leads to the formation of gene families, wherein purifying or neutral selection maintains the original gene function, while diversifying selection confers new functions onto duplicated genes. The B56 gene family is highly conserved; it is encoded by one gene in protists and fungi, and five genes in vertebrates. B56 regulates protein phosphatase 2A (PP2A), an abundant heterotrimeric serine/threonine phosphatase that functions as a tumor suppressor and consists of a scaffolding “A” and catalytic “C” subunit heterodimer bound to a regulatory “B” subunit. Individual regulatory B56 subunits confer disparate functions onto PP2A in various cell-cell signaling pathways. B56 proteins share a conserved central core domain, but have divergent N- and C-termini which play a role in isoform specificity. We carried out a nonsynonymous/synonymous substitution analysis to better understand the divergence of vertebrate B56 genes. When five B56 paralogs from ten vertebrate species were analyzed, the gene family displayed purifying selection; stronger purifying selection was revealed when individual B56 isoforms were analyzed separately. The B56 core experienced stronger purifying selection than the N- and C-termini, which correlates with the presence of several contacts between the core and the AC heterodimer. Indeed, the majority of the contact points that we analyzed between B56 and the AC heterodimer experienced strong purifying selection. B56 subfamilies showed distinct patterns of selection in their N- and C-termini. The C-terminus of the B56-1 subfamily and the N-terminus of the B56-2 subfamily exhibited strong purifying selection, suggesting that these termini carry out subfamily-specific functions, while the opposite termini exhibited diversifying selection and likely carry out isoform-specific functions. We also found reduced synonymous substitutions at the N- and C-termini when grouping B56 genes by species but not by isoform, suggesting species-specific codon bias may have a role in regulating B56 gene expression.
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Affiliation(s)
- Osama Qureshi
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX, United States of America
| | - Hyuk Cho
- Department of Computer Science, Sam Houston State University, Huntsville, TX, United States of America
| | - Madhusudan Choudhary
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX, United States of America
| | - Joni M Seeling
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX, United States of America
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21
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Zhou S, Flamier A, Abdouh M, Tétreault N, Barabino A, Wadhwa S, Bernier G. Differentiation of human embryonic stem cells into cone photoreceptors through simultaneous inhibition of BMP, TGFβ and Wnt signaling. Development 2015; 142:3294-306. [DOI: 10.1242/dev.125385] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cone photoreceptors are required for color discrimination and high-resolution central vision and are lost in macular degenerations, cone and cone/rod dystrophies. Cone transplantation could represent a therapeutic solution. However, an abundant source of human cones remains difficult to obtain. Work performed in model organisms suggests that anterior neural cell fate is induced ‘by default' if BMP, TGFβ and Wnt activities are blocked, and that photoreceptor genesis operates through an S-cone default pathway. We report here that Coco (Dand5), a member of the Cerberus gene family, is expressed in the developing and adult mouse retina. Upon exposure to recombinant COCO, human embryonic stem cells (hESCs) differentiated into S-cone photoreceptors, developed an inner segment-like protrusion, and could degrade cGMP when exposed to light. Addition of thyroid hormone resulted in a transition from a unique S-cone population toward a mixed M/S-cone population. When cultured at confluence for a prolonged period of time, COCO-exposed hESCs spontaneously developed into a cellular sheet composed of polarized cone photoreceptors. COCO showed dose-dependent and synergistic activity with IGF1 at blocking BMP/TGFβ/Wnt signaling, while its cone-inducing activity was blocked in a dose-dependent manner by exposure to BMP, TGFβ or Wnt-related proteins. Our work thus provides a unique platform to produce human cones for developmental, biochemical and therapeutic studies and supports the hypothesis that photoreceptor differentiation operates through an S-cone default pathway during human retinal development.
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Affiliation(s)
- Shufeng Zhou
- Stem Cell and Developmental Biology Laboratory, Maisonneuve-Rosemont Hospital, 5415 Boul. l'Assomption, Montréal, Canada H1T 2M4
| | - Anthony Flamier
- Stem Cell and Developmental Biology Laboratory, Maisonneuve-Rosemont Hospital, 5415 Boul. l'Assomption, Montréal, Canada H1T 2M4
| | - Mohamed Abdouh
- Stem Cell and Developmental Biology Laboratory, Maisonneuve-Rosemont Hospital, 5415 Boul. l'Assomption, Montréal, Canada H1T 2M4
| | - Nicolas Tétreault
- Stem Cell and Developmental Biology Laboratory, Maisonneuve-Rosemont Hospital, 5415 Boul. l'Assomption, Montréal, Canada H1T 2M4
| | - Andrea Barabino
- Stem Cell and Developmental Biology Laboratory, Maisonneuve-Rosemont Hospital, 5415 Boul. l'Assomption, Montréal, Canada H1T 2M4
| | - Shashi Wadhwa
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Gilbert Bernier
- Stem Cell and Developmental Biology Laboratory, Maisonneuve-Rosemont Hospital, 5415 Boul. l'Assomption, Montréal, Canada H1T 2M4
- Department of Neuroscience, University of Montréal, Montréal H3T 1J4, Canada
- Department of Ophthalmology, University of Montréal, Montréal H3T 1J4, Canada
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22
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Insulin-like factor regulates neural induction through an IGF1 receptor-independent mechanism. Sci Rep 2015; 5:11603. [PMID: 26112133 PMCID: PMC4481404 DOI: 10.1038/srep11603] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 05/29/2015] [Indexed: 01/15/2023] Open
Abstract
Insulin receptor (IR) and insulin-like growth factor-1 receptor (IGF1R) signalling is required for normal embryonic growth and development. Previous reports indicated that the IGF/IGF1R/MAPK pathway contributes to neural induction and the IGF/IGF1R/PI3K/Akt pathway to eye development. Here, we report the isolation of insulin3 encoding a novel insulin-like ligand involved in neural induction. Insulin3 has a similar structure to pro-insulin and mature IGF ligands, but cannot activate the IGF1 receptor. However, similar to IGFs, Insulin3 induced the gene expression of an anterior neural marker, otx2, and enlarged anterior head structures by inhibiting Wnt signalling. Insulin3 are predominantly localised to the endoplasmic reticulum when otx2 is induced by insulin3. Insulin3 reduced extracellular Wnts and cell surface localised Lrp6. These results suggest that Insulin3 is a novel cell-autonomous inhibitor of Wnt signalling. This study provides the first evidence that an insulin-like factor regulates neural induction through an IGF1R-independent mechanism.
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23
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Sommer LM, Cho H, Choudhary M, Seeling JM. Evolutionary Analysis of the B56 Gene Family of PP2A Regulatory Subunits. Int J Mol Sci 2015; 16:10134-57. [PMID: 25950761 PMCID: PMC4463637 DOI: 10.3390/ijms160510134] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 04/22/2015] [Accepted: 04/24/2015] [Indexed: 02/08/2023] Open
Abstract
Protein phosphatase 2A (PP2A) is an abundant serine/threonine phosphatase that functions as a tumor suppressor in numerous cell-cell signaling pathways, including Wnt, myc, and ras. The B56 subunit of PP2A regulates its activity, and is encoded by five genes in humans. B56 proteins share a central core domain, but have divergent amino- and carboxy-termini, which are thought to provide isoform specificity. We performed phylogenetic analyses to better understand the evolution of the B56 gene family. We found that B56 was present as a single gene in eukaryotes prior to the divergence of animals, fungi, protists, and plants, and that B56 gene duplication prior to the divergence of protostomes and deuterostomes led to the origin of two B56 subfamilies, B56αβε and B56γδ. Further duplications led to three B56αβε genes and two B56γδ in vertebrates. Several nonvertebrate B56 gene names are based on distinct vertebrate isoform names, and would best be renamed. B56 subfamily genes lack significant divergence within primitive chordates, but each became distinct in complex vertebrates. Two vertebrate lineages have undergone B56 gene loss, Xenopus and Aves. In Xenopus, B56δ function may be compensated for by an alternatively spliced transcript, B56δ/γ, encoding a B56δ-like amino-terminal region and a B56γ core.
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Affiliation(s)
- Lauren M Sommer
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX 77341, USA.
| | - Hyuk Cho
- Department of Computer Science, Sam Houston State University, Huntsville, TX 77341, USA.
| | - Madhusudan Choudhary
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX 77341, USA.
| | - Joni M Seeling
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX 77341, USA.
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24
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Li X, Nan A, Xiao Y, Chen Y, Lai Y. PP2A-B56ϵ complex is involved in dephosphorylation of γ-H2AX in the repair process of CPT-induced DNA double-strand breaks. Toxicology 2015; 331:57-65. [PMID: 25772433 DOI: 10.1016/j.tox.2015.03.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 02/25/2015] [Accepted: 03/11/2015] [Indexed: 10/23/2022]
Abstract
Phosphorylation of histone H2AX (γ-H2AX) in response to DNA double-strand breaks (DSBs) should be eliminated from the sites of DNA damage to fulfill the DNA repair and release cells from the growth arrest. Previous study showed that protein phosphatase 2A (PP2A) interact with γ-H2AX that lead to the dephosphorylation of γ-H2AX. Here, we examined the effects of suppression of PP2A regulatory subunits on dephosphorylation of γ-H2AX in human embryonic kidney epithelial cells (HEK) treated by topoisomerase I inhibitor camptothecin (CPT). We found that cells with suppression of B55α or B56ϵ were more sensitive to DNA damage agents. Suppression of B56ϵ led to persistence of γ-H2AX, resulting in prolonged DSBs repair and increased chromatin instability measured by comet assay. In addition, the deficiency of B56ϵ impaired the cell cycle regulation and the DNA repair pathway of homologous recombination (HR). Notably, we detected that PP2A B56ϵ subunit was involved directly in dephosphorylation of γ-H2AX and translocated from cytoplasm to nucleus upon the treatment of CPT. Our findings demonstrate that PP2A holoenzyme containing B56ϵ is responsible for the dephosphorylation of γ-H2AX and regulation of DNA repair of DSBs induced by CPT.
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Affiliation(s)
- Xiuying Li
- Institute for Chemical Carcinogenesis, Guangzhou Medical University, Guangzhou 510182, China; College of Pharmacy, Jinan University, Guangzhou 510632, China
| | - Anuo Nan
- Institute for Chemical Carcinogenesis, Guangzhou Medical University, Guangzhou 510182, China
| | - Ying Xiao
- College of Pharmacy, Jinan University, Guangzhou 510632, China
| | - Yongzhong Chen
- Institute for Chemical Carcinogenesis, Guangzhou Medical University, Guangzhou 510182, China
| | - Yandong Lai
- Institute for Chemical Carcinogenesis, Guangzhou Medical University, Guangzhou 510182, China.
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25
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Jin Z, Chung JW, Mei W, Strack S, He C, Lau GW, Yang J. Regulation of nuclear-cytoplasmic shuttling and function of Family with sequence similarity 13, member A (Fam13a), by B56-containing PP2As and Akt. Mol Biol Cell 2015; 26:1160-73. [PMID: 25609086 PMCID: PMC4357514 DOI: 10.1091/mbc.e14-08-1276] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Recent genome-wide association studies reveal that the FAM13A gene is associated with human lung function and a variety of lung diseases, including chronic obstructive pulmonary disease, asthma, lung cancer, and pulmonary fibrosis. The biological functions of Fam13a, however, have not been studied. In an effort to identify novel substrates of B56-containing PP2As, we found that B56-containing PP2As and Akt act antagonistically to control reversible phosphorylation of Fam13a on Ser-322. We show that Ser-322 phosphorylation acts as a molecular switch to control the subcellular distribution of Fam13a. Fam13a shuttles between the nucleus and cytoplasm. When Ser-322 is phosphorylated by Akt, the binding between Fam13a and 14-3-3 is enhanced, leading to cytoplasmic sequestration of Fam13a. B56-containing PP2As dephosphorylate phospho-Ser-322 and promote nuclear localization of Fam13a. We generated Fam13a-knockout mice. Fam13a-mutant mice are viable and healthy, indicating that Fam13a is dispensable for embryonic development and physiological functions in adult animals. Intriguingly, Fam13a has the ability to activate the Wnt pathway. Although Wnt signaling remains largely normal in Fam13a-knockout lungs, depletion of Fam13a in human lung cancer cells causes an obvious reduction in Wnt signaling activity. Our work provides important clues to elucidating the mechanism by which Fam13a may contribute to human lung diseases.
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Affiliation(s)
- Zhigang Jin
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802
| | - Jin Wei Chung
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802
| | - Wenyan Mei
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802
| | - Stefan Strack
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA 52242
| | - Chunyan He
- Department of Epidemiology, Richard M. Fairbanks School of Public Health, Indiana University, Indianapolis, IN 46202
| | - Gee W Lau
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802
| | - Jing Yang
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802
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26
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Liu X, Liu Q, Fan Y, Wang S, Liu X, Zhu L, Liu M, Tang H. Downregulation of PPP2R5E expression by miR-23a suppresses apoptosis to facilitate the growth of gastric cancer cells. FEBS Lett 2014; 588:3160-9. [DOI: 10.1016/j.febslet.2014.05.068] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/22/2014] [Accepted: 05/22/2014] [Indexed: 01/29/2023]
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27
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Schwend T, Jin Z, Jiang K, Mitchell BJ, Jia J, Yang J. Stabilization of speckle-type POZ protein (Spop) by Daz interacting protein 1 (Dzip1) is essential for Gli turnover and the proper output of Hedgehog signaling. J Biol Chem 2013; 288:32809-32820. [PMID: 24072710 DOI: 10.1074/jbc.m113.512962] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The Hedgehog (Hh) pathway is essential for embryonic development and adult tissue homeostasis. The Gli/Cubitus interruptus (Ci) family of transcription factors acts at the downstream end of the pathway to mediate Hh signaling. Both Hh-dependent and -independent Gli regulatory mechanisms are important for the output of Hh signaling. Daz interacting protein 1 (Dzip1) has bipartite positive and negative functions in the Hh pathway. The positive Hh regulatory function appears to be attributed to a requirement for Dzip1 during ciliogenesis. The mechanism by which Dzip1 inhibits Hh signaling, however, remains largely unclear. We recently found that Dzip1 is required for Gli turnover, which may account for its inhibitory function in Hh signaling. Here, we report that Dzip1 regulates Gli/Ci turnover by preventing degradation of speckle-type POZ protein (Spop), a protein that promotes proteasome-dependent turnover of Gli proteins. We provide evidence that Dzip1 regulates the stability of Spop independent of its function in ciliogenesis. Partial knockdown of Dzip1 to levels insufficient for perturbing ciliogenesis, sensitized Xenopus embryos to Hh signaling, leading to phenotypes that resemble activation of Hh signaling. Importantly, overexpression of Spop was able to restore proper Gli protein turnover and rescue phenotypes in Dzip1-depleted embryos. Consistently, depletion of Dzip1 in Drosophila S2 cells destabilized Hh-induced BTB protein (HIB), the Drosophila homolog of Spop, and increased the level of Ci. Thus, Dzip1-dependent stabilization of Spop/HIB is evolutionarily conserved and essential for proper regulation of Gli/Ci proteins in the Hh pathway.
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Affiliation(s)
- Tyler Schwend
- From the Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802
| | - Zhigang Jin
- From the Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802
| | - Kai Jiang
- Markey Cancer Center, Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536-0509
| | - Brian J Mitchell
- Department of Cell and Molecular Biology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60611
| | - Jianhang Jia
- Markey Cancer Center, Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536-0509
| | - Jing Yang
- From the Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802,.
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28
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Cristóbal I, Cirauqui C, Castello-Cros R, Garcia-Orti L, Calasanz MJ, Odero MD. Downregulation of PPP2R5E is a common event in acute myeloid leukemia that affects the oncogenic potential of leukemic cells. Haematologica 2013; 98:e103-4. [PMID: 23812941 DOI: 10.3324/haematol.2013.084731] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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29
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Xu Y, Xu C, Kato A, Tempel W, Abreu JG, Bian C, Hu Y, Hu D, Zhao B, Cerovina T, Diao J, Wu F, He HH, Cui Q, Clark E, Ma C, Barbara A, Veenstra GJC, Xu G, Kaiser UB, Liu XS, Sugrue SP, He X, Min J, Kato Y, Shi YG. Tet3 CXXC domain and dioxygenase activity cooperatively regulate key genes for Xenopus eye and neural development. Cell 2012; 151:1200-13. [PMID: 23217707 PMCID: PMC3705565 DOI: 10.1016/j.cell.2012.11.014] [Citation(s) in RCA: 190] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 09/19/2012] [Accepted: 11/09/2012] [Indexed: 11/26/2022]
Abstract
Ten-Eleven Translocation (Tet) family of dioxygenases dynamically regulates DNA methylation and has been implicated in cell lineage differentiation and oncogenesis. Yet their functions and mechanisms of action in gene regulation and embryonic development are largely unknown. Here, we report that Xenopus Tet3 plays an essential role in early eye and neural development by directly regulating a set of key developmental genes. Tet3 is an active 5mC hydroxylase regulating the 5mC/5hmC status at target gene promoters. Biochemical and structural studies further demonstrate that the Tet3 CXXC domain is critical for specific Tet3 targeting. Finally, we show that the enzymatic activity and CXXC domain are both crucial for Tet3's biological function. Together, these findings define Tet3 as a transcription regulator and reveal a molecular mechanism by which the 5mC hydroxylase and DNA binding activities of Tet3 cooperate to control target gene expression and embryonic development.
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Affiliation(s)
- Yufei Xu
- Division of Endocrinology, Diabetes and Hypertension, Departments of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Chao Xu
- Structural Genomics Consortium and Department of Physiology, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Akiko Kato
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL 32306, USA
| | - Wolfram Tempel
- Structural Genomics Consortium and Department of Physiology, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Jose Garcia Abreu
- F.M. Kirby Neurobiology Center, Children’s Hospital Boston, Harvard Medical School, Boston, MA 02115, USA
| | - Chuanbing Bian
- Structural Genomics Consortium and Department of Physiology, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Yeguang Hu
- Division of Endocrinology, Diabetes and Hypertension, Departments of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Di Hu
- Division of Endocrinology, Diabetes and Hypertension, Departments of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Laboratory of Epigenetics, Institutes of Biomedical Science, Fudan University, Shanghai 200032, P.R. China
| | - Bin Zhao
- Laboratory of Epigenetics, Institutes of Biomedical Science, Fudan University, Shanghai 200032, P.R. China
| | - Tanja Cerovina
- Structural Genomics Consortium and Department of Physiology, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Jianbo Diao
- Laboratory of Epigenetics, Institutes of Biomedical Science, Fudan University, Shanghai 200032, P.R. China
| | - Feizhen Wu
- Laboratory of Epigenetics, Institutes of Biomedical Science, Fudan University, Shanghai 200032, P.R. China
| | - Housheng Hansen He
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute and Harvard School of Public Health, Boston, MA 02115, USA
| | - Qingyan Cui
- The State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, P.R. China
| | - Erin Clark
- Division of Endocrinology, Diabetes and Hypertension, Departments of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Chun Ma
- Division of Endocrinology, Diabetes and Hypertension, Departments of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Laboratory of Epigenetics, Institutes of Biomedical Science, Fudan University, Shanghai 200032, P.R. China
| | - Andrew Barbara
- Division of Endocrinology, Diabetes and Hypertension, Departments of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Gert Jan C. Veenstra
- Radboud University Nijmegen, Nijmegen Center for Molecular Life Sciences, Nijmegen 6500 HB, The Netherlands
| | - Guoliang Xu
- The State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, P.R. China
| | - Ursula B. Kaiser
- Division of Endocrinology, Diabetes and Hypertension, Departments of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - X. Shirley Liu
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute and Harvard School of Public Health, Boston, MA 02115, USA
- Center for Functional Cancer Epigenetics, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Stephen P. Sugrue
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL 32610, USA
| | - Xi He
- F.M. Kirby Neurobiology Center, Children’s Hospital Boston, Harvard Medical School, Boston, MA 02115, USA
| | - Jinrong Min
- Structural Genomics Consortium and Department of Physiology, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Yoichi Kato
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL 32306, USA
| | - Yujiang Geno Shi
- Division of Endocrinology, Diabetes and Hypertension, Departments of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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30
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WIP1 phosphatase modulates the Hedgehog signaling by enhancing GLI1 function. Oncogene 2012; 32:4737-47. [PMID: 23146903 DOI: 10.1038/onc.2012.502] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 09/10/2012] [Accepted: 09/18/2012] [Indexed: 02/06/2023]
Abstract
The Hedgehog-GLI (HH-GLI) signaling plays a critical role in controlling growth and tissue patterning during embryogenesis and is implicated in a variety of human malignancies, including those of the skin. Phosphorylation events have been shown to regulate the activity of the GLI transcription factors, the final effectors of the HH-GLI signaling pathway. Here, we show that WIP1 (or PPM1D), an oncogenic phosphatase amplified/overexpressed in several types of human cancer, is a positive modulator of the HH signaling. Mechanistically, WIP1 enhances the function of GLI1 by increasing its transcriptional activity, nuclear localization and protein stability, but not of GLI2 nor GLI3. We also find that WIP1 and GLI1 are in a complex. Modulation of the transcriptional activity of GLI1 by WIP1 depends on the latter's phosphatase activity and, remarkably, does not require p53, a known WIP1 target. Functionally, we find that WIP1 is required for melanoma and breast cancer cell proliferation and self-renewal in vitro and melanoma xenograft growth induced by activation of the HH signaling. Pharmacological blockade of the HH pathway with the SMOOTHENED antagonist cyclopamine acts synergistically with inhibition of WIP1 in reducing growth of melanoma and breast cancer cells in vitro. Overall, our data uncover a role for WIP1 in modulating the activity of GLI1 and in sustaining cancer cell growth and cancer stem cell self-renewal induced by activation of the HH pathway. These findings open a novel therapeutic approach for human melanomas and, possibly, other cancer types expressing WIP1 and with activated HH pathway.
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Abstract
The study of posttranslational regulation of proteins has occupied biochemists for well over a half century. Understanding balanced phosphorylation and dephosphorylation of the proteins may be the key to meeting some of the most pressing scientific challenges. A detailed examination of the phosphorylation of many components in the Hedgehog (Hh) pathway leads to a better understanding of the Hh signaling mechanisms. This chapter describes the precise phosphorylation that evolves during the phosphorylation/dephosphorylation of players in the Hh signaling cascade, including the signal transducer Smoothened and the transcription factor Ci/Gli.
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Affiliation(s)
- Jianhang Jia
- Department of Molecular and Cellular Biochemistry, Markey Cancer Center, University of Kentucky College of Medicine, Lexington, Kentucky, USA
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32
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Jin Z, Mei W, Strack S, Jia J, Yang J. The antagonistic action of B56-containing protein phosphatase 2As and casein kinase 2 controls the phosphorylation and Gli turnover function of Daz interacting protein 1. J Biol Chem 2011; 286:36171-9. [PMID: 21878643 DOI: 10.1074/jbc.m111.274761] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The Hedgehog (Hh) pathway is evolutionarily conserved and plays critical roles during embryonic development and adult tissue homeostasis. Defective Hh signaling has been linked to a wide range of birth defects and cancers. Hh family proteins regulate the expression of their downstream target genes through the control of proteolytic processing and the transcriptional activation function of Gli transcription factors. Although Hh-dependent regulation of Gli has been studied extensively, other Gli regulatory mechanisms remain relatively unappreciated. Here we report our identification of a novel signaling cascade that controls the stability of Gli proteins. This cascade consists of Daz interacting protein 1 (Dzip1), casein kinase 2 (CK2), and B56 containing protein phosphatase 2As (PP2As). We provide evidence that Dzip1 is involved in a novel Gli turnover pathway. We show that CK2 directly phosphorylates Dzip1 at four serine residues, Ser-664/665/706/714. B56-containing PP2As, through binding to a domain located between amino acid residue 474 and 550 of Dzip1, dephosphorylate Dzip1 on these CK2 sites. Our mutagenesis analysis further demonstrates that the unphosphorylatable form of Dzip1 is more potent in promoting Gli turnover. Consistently, we found that the stability of Gli proteins was decreased upon CK2 inhibition and increased by inhibition of B56-containing PP2As. Thus, reversible phosphorylation of Dzip1, which is controlled by the antagonistic action of CK2 and B56-containing PP2As, has an important impact on the stability of Gli transcription factors and Hh signaling.
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Affiliation(s)
- Zhigang Jin
- The Research Institute at Nationwide Children's Hospital, Department of Pediatrics, the Ohio State University, Columbus, Ohio 43205, USA
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33
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Bugner V, Aurhammer T, Kühl M. Xenopus laevis insulin receptor substrate IRS-1 is important for eye development. Dev Dyn 2011; 240:1705-15. [DOI: 10.1002/dvdy.22659] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/22/2011] [Indexed: 12/30/2022] Open
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Mainwaring LA, Kenney AM. Divergent functions for eIF4E and S6 kinase by sonic hedgehog mitogenic signaling in the developing cerebellum. Oncogene 2011; 30:1784-97. [PMID: 21339731 DOI: 10.1038/onc.2010.564] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cerebellar development entails rapid peri-natal proliferation of cerebellar granule neuron precursors (CGNPs), proposed cells-of-origin for certain medulloblastomas. CGNPs require insulin-like growth factor (IGF) for survival and sonic hedgehog (Shh)-implicated in medulloblastoma-for proliferation. The IGF-responsive kinase mammalian target of rapamycin (mTOR) drives proliferation-associated protein synthesis. We asked whether Shh signaling regulates mTOR targets to promote CGNP proliferation despite constitutive IGF signaling under proliferative and differentiation-promoting conditions. Surprisingly, Shh promoted eukaryotic initiation factor 4E (eIF4E) expression, but inhibited S6 kinase (S6K). In vivo, S6K activity specifically marked the CGNP population transitioning from proliferation-competent to post-mitotic. Indeed, eIF4E was required for CGNP proliferation, while S6K activation drove cell cycle exit. Protein phosphatase 2A (PP2A) inhibition rescued S6K activity. Moreover, Shh upregulated the PP2A B56γ subunit, which targets S6K for inactivation and was required for CGNP proliferation. These findings reveal unique developmental functions for eIF4E and S6 kinase wherein their activity is specifically uncoupled by mitogenic Shh signaling.
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Affiliation(s)
- L A Mainwaring
- Biochemistry, Cell, and Molecular Biology Program, Weill Medical College of Cornell University, New York, NY, USA
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35
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Kim JW, Jang SM, Kim CH, An JH, Kang EJ, Choi KH. Neural retina leucine-zipper regulates the expression of Ppp2r5c, the regulatory subunit of protein phosphatase 2A, in photoreceptor development. FEBS J 2010; 277:5051-60. [DOI: 10.1111/j.1742-4658.2010.07910.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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36
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Yang J, Phiel C. Functions of B56-containing PP2As in major developmental and cancer signaling pathways. Life Sci 2010; 87:659-66. [PMID: 20934435 DOI: 10.1016/j.lfs.2010.10.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 09/08/2010] [Accepted: 09/23/2010] [Indexed: 12/20/2022]
Abstract
Members of the B'/B56/PR61 family regulatory subunits of PP2A determine the subcellular localization, substrate specificity, and catalytic activity of PP2A in a wide range of biological processes. Here, we summarize the structure and intracellular localization of B56-containing PP2As and review functions of B56-containing PP2As in several major developmental/cancer signaling pathways.
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Affiliation(s)
- Jing Yang
- The Research Institute at Nationwide Children's Hospital, Department of Pediatrics, the Ohio State University, 700 Children's Dr., Columbus, OH, 43205, United States.
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37
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Jin Z, Wallace L, Harper SQ, Yang J. PP2A:B56{epsilon}, a substrate of caspase-3, regulates p53-dependent and p53-independent apoptosis during development. J Biol Chem 2010; 285:34493-502. [PMID: 20807766 DOI: 10.1074/jbc.m110.169581] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Protein phosphatase 2A (PP2A) is one of the most abundantly expressed serine/threonine protein phosphatases. A large body of evidence suggests that PP2A is a tumor suppressor and plays critical roles in regulating apoptosis. PP2A is a heterotrimeric protein complex. Its substrate specificity, localization, and activity are regulated by regulatory subunits of PP2A. A recent study has demonstrated that single nucleotide polymorphism in B56ε (PPP2R5E), a B56 family regulatory subunit of PP2A, is associated with human soft tissue sarcoma. This raises the possibility that B56ε is involved in tumorigenesis and plays important roles in regulating apoptosis. However, this hypothesis has not been tested experimentally. Our previous studies revealed that B56ε regulates a number of developmental signaling pathways during early embryonic patterning. Here we report novel functions of B56ε in regulating apoptosis. We provide evidence that B56ε has both anti- and pro-apoptotic functions. B56ε suppresses p53-independent apoptosis during neural development, but triggers p53-dependent apoptosis. Mechanistically, B56ε regulates the p53-dependent apoptotic pathway solely through controlling the stability of p53 protein. In addition to its function in regulating apoptosis, we show that B56ε undergoes proteolytic cleavage. The cleavage of B56ε is mediated by caspase-3 and occurs on the carboxyl side of an evolutionarily conserved N-terminal "DKXD" motif. These results demonstrate that B56ε, a substrate of caspase-3, is an essential regulator of apoptosis. So far, we have identified an alternative translation isoform and a caspase cleavage product of B56ε. The significance of post-transcriptional regulation of B56ε is discussed.
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Affiliation(s)
- Zhigang Jin
- Department of Pediatrics, Research Institute at Nationwide Children's Hospital, Ohio State University, Columbus, Ohio 43205, USA
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38
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Ma HL, Peng YL, Gong L, Liu WB, Sun S, Liu J, Zheng CB, Fu H, Yuan D, Zhao J, Chen PC, Xie SS, Zeng XM, Xiao YM, Liu Y, Li DWC. The goldfish SG2NA gene encodes two alpha-type regulatory subunits for PP-2A and displays distinct developmental expression pattern. GENE REGULATION AND SYSTEMS BIOLOGY 2009; 3:115-29. [PMID: 19838339 PMCID: PMC2758282 DOI: 10.4137/grsb.s2764] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
SG2NA is a member of the striatin protein family. In human and mouse, the SG2NA gene encodes two major protein isoforms: SG2NA alpha and SG2NA beta. The functions of these proteins, except for acting as the regulatory subunits for PP-2A, remain largely unknown. To explore the possible functions of SG2NA in lower vertebrates, we have isolated two SG2NA cDNAs from goldfish, Carassius auratus. Our results reveal that the first cDNA contains an ORF of 2118 bp encoding a deduced protein with 705 amino acids, and the second one 2148 bp coding for a deduced protein of 715 amino acids. Comparative analysis reveals that both isoforms belong to the alpha-type, and are named SG2NA alpha and SG2NA alpha(+). RT-PCR and western blot analysis reveal that the SG2NA gene is differentially expressed in 9 tissues examined. During goldfish development, while the SG2NA mRNAs remain relatively constant in the first 3 stages and then become decreased and fluctuated from gastrula to larval hatching, the SG2NA proteins are fluctuated, displaying a peak every 3 to 4 stages. Each later peak is higher than the earlier one and the protein expression level becomes maximal at hatching stage. Together, our results reveal that SG2NA may play an important role during goldfish development and also in homeostasis of most adult tissues.
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Affiliation(s)
- Hai-Li Ma
- Key Laboratory of Protein Chemistry and Developmental Biology of Education Ministry of China, College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China
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A GLI1-p53 inhibitory loop controls neural stem cell and tumour cell numbers. EMBO J 2009; 28:663-76. [PMID: 19214186 PMCID: PMC2647769 DOI: 10.1038/emboj.2009.16] [Citation(s) in RCA: 191] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Accepted: 01/09/2009] [Indexed: 01/05/2023] Open
Abstract
How cell numbers are determined is not understood. Hedgehog-Gli activity is involved in precursor cell proliferation and stem cell self-renewal, and its deregulation sustains the growth of many human tumours. However, it is not known whether GLI1, the final mediator of Hh signals, controls stem cell numbers, and how its activity is restricted to curtail tumourigenesis. Here we have altered the levels of GLI1 and p53, the major tumour suppressor, in multiple systems. We show that GLI1 expression in Nestin+ neural progenitors increases precursor and clonogenic stem cell numbers in vivo and in vitro. In contrast, p53 inhibits GLI1-driven neural stem cell self-renewal, tumour growth and proliferation. Mechanistically, p53 inhibits the activity, nuclear localisation and levels of GLI1 and in turn, GLI1 represses p53, establishing an inhibitory loop. We also find that p53 regulates the phosphorylation of a novel N' truncated putative activator isoform of GLI1 in human cells. The balance of GLI1 and p53 functions, thus, determines cell numbers, and prevalence of p53 restricts GLI1-driven stem cell expansion and tumourigenesis.
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40
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hnRNP I inhibits Notch signaling and regulates intestinal epithelial homeostasis in the zebrafish. PLoS Genet 2009; 5:e1000363. [PMID: 19197356 PMCID: PMC2629577 DOI: 10.1371/journal.pgen.1000363] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Accepted: 12/31/2008] [Indexed: 01/27/2023] Open
Abstract
Regulated intestinal stem cell proliferation and differentiation are required for normal intestinal homeostasis and repair after injury. The Notch signaling pathway plays fundamental roles in the intestinal epithelium. Despite the fact that Notch signaling maintains intestinal stem cells in a proliferative state and promotes absorptive cell differentiation in most species, it remains largely unclear how Notch signaling itself is precisely controlled during intestinal homeostasis. We characterized the intestinal phenotypes of brom bones, a zebrafish mutant carrying a nonsense mutation in hnRNP I. We found that the brom bones mutant displays a number of intestinal defects, including compromised secretory goblet cell differentiation, hyperproliferation, and enhanced apoptosis. These phenotypes are accompanied by a markedly elevated Notch signaling activity in the intestinal epithelium. When overexpressed, hnRNP I destabilizes the Notch intracellular domain (NICD) and inhibits Notch signaling. This activity of hnRNP I is conserved from zebrafish to human. In addition, our biochemistry experiments demonstrate that the effect of hnRNP I on NICD turnover requires the C-terminal portion of the RAM domain of NICD. Our results demonstrate that hnRNP I is an evolutionarily conserved Notch inhibitor and plays an essential role in intestinal homeostasis.
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Jin Z, Shi J, Saraf A, Mei W, Zhu GZ, Strack S, Yang J. The 48-kDa alternative translation isoform of PP2A:B56epsilon is required for Wnt signaling during midbrain-hindbrain boundary formation. J Biol Chem 2009; 284:7190-200. [PMID: 19129191 DOI: 10.1074/jbc.m807907200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Alternative translation is an underappreciated post-transcriptional regulation mechanism. Although only a small number of genes are found to be alternatively translated, most genes undergoing alternative translation play important roles in tumorigenesis and development. Protein phosphatase 2A (PP2A) is involved in many cellular events during tumorigenesis and development. The specificity, localization, and activity of PP2A are regulated by B regulatory subunits. B56epsilon, a member of the B56 regulatory subunit family, is involved in multiple signaling pathways and regulates a number of developmental processes. Here we report that B56epsilon is alternatively translated, leading to the production of a full-length form and a shorter isoform that lacks the N-terminal 76 amino acid residues of the full-length form. Alternative translation of B56epsilon occurs through a cap-dependent mechanism. We provide evidence that the shorter isoform is required for Wnt signaling and regulates the midbrain/hindbrain boundary formation during Xenopus embryonic development. This demonstrates that the shorter isoform of B56epsilon has important biological functions. Furthermore, we show that the N-terminal sequence of B56epsilon, which is not present in the shorter isoform, contains a nuclear localization signal, whereas the C terminus of B56epsilon contains a nuclear export signal. The shorter isoform, which lacks the N-terminal nuclear localization signal, is restricted to the cytoplasm. In contrast, the full-length form can be localized to the nucleus in a cell type-specific manner. The finding that B56epsilon is alternatively translated adds a new level of regulation to PP2A holoenzymes.
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Affiliation(s)
- Zhigang Jin
- Center for Cell and Development Biology, the Research Institute at Nationwide Children's Hospital, Department of Pediatrics, Ohio State University, Columbus, Ohio 43205, USA
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Jia H, Liu Y, Yan W, Jia J. PP4 and PP2A regulate Hedgehog signaling by controlling Smo and Ci phosphorylation. Development 2008; 136:307-16. [PMID: 19088085 DOI: 10.1242/dev.030015] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The seven-transmembrane protein Smoothened (Smo) and Zn-finger transcription factor Ci/Gli are crucial components in Hedgehog (Hh) signal transduction that mediates a variety of processes in animal development. In Drosophila, multiple kinases have been identified to regulate Hh signaling by phosphorylating Smo and Ci; however, the phosphatase(s) involved remain obscured. Using an in vivo RNAi screen, we identified PP4 and PP2A as phosphatases that influence Hh signaling by regulating Smo and Ci, respectively. RNAi knockdown of PP4, but not of PP2A, elevates Smo phosphorylation and accumulation, leading to increased Hh signaling activity. Deletion of a PP4-interaction domain (amino acids 626-678) in Smo promotes Smo phosphorylation and signaling activity. We further find that PP4 regulates the Hh-induced Smo cell-surface accumulation. Mechanistically, we show that Hh downregulates Smo-PP4 interaction that is mediated by Cos2. We also provide evidence that PP2A is a Ci phosphatase. Inactivating PP2A regulatory subunit (Wdb) by RNAi or by loss-of-function mutation downregulates, whereas overexpressing regulatory subunit upregulates, the level and thus signaling activity of full-length Ci. Furthermore, we find that Wdb counteracts kinases to prevent Ci phosphorylation. Finally, we have obtained evidence that Wdb attenuates Ci processing probably by dephosphorylating Ci. Taken together, our results suggest that PP4 and PP2A are two phosphatases that act at different positions of the Hh signaling cascade.
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Affiliation(s)
- Hongge Jia
- Sealy Center for Cancer Cell Biology, Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
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Zebrafish olfactomedin 1 regulates retinal axon elongation in vivo and is a modulator of Wnt signaling pathway. J Neurosci 2008; 28:7900-10. [PMID: 18667622 DOI: 10.1523/jneurosci.0617-08.2008] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Olfactomedin 1 (Olfm1) is a secreted glycoprotein belonging to a family of olfactomedin domain-containing proteins. It is involved in the regulation of neural crest production in chicken and promotes neuronal differentiation in Xenopus. Here, we investigate the functions of Olfm1 in zebrafish eye development. Overexpression of full-length Olfm1, and especially its BMY form lacking the olfactomedin domain, increased the thickness of the optic nerve and produced a more extended projection field in the optic tectum compared with control embryos. In contrast, injection of olfm1-morpholino oligonucleotide (Olfm1-MO) reduced the eye size, inhibited optic nerve extension, and increased the number of apoptotic cells in the retinal ganglion cell and inner nuclear layers. Overexpression of full-length Olfm1 increased the lateral separation of the expression domains of eye-field markers, rx3 and six3. The Olfm1-MO had the opposite effect. These data suggest that zebrafish Olfm1 may play roles in the early eye determination, differentiation, optic nerve extension, and branching of the retinal ganglion cell axon terminals, with the N-terminal region of Olfm1 being critical for these effects. Injection of RNA encoding WIF-1, a secreted inhibitor of Wnt signaling, caused changes in the expression pattern of rx3 similar to those observed after Olfm1-MO injection. Simultaneous overexpression of WIF-1 and Olfm1 abolished the WIF-1 effect. Physical interaction of WIF-1 and Olfm1 was demonstrated by coimmunoprecipitation experiments. We concluded that Olfm1 serves as a modulator of Wnt signaling.
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