1
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Tian J, Pu M, Chen B, Wang G, Li C, Zhang X, Yu Y, Wang Z, Kong Z. Verticillium dahliae Asp1 regulates the transition from vegetative growth to asexual reproduction by modulating microtubule dynamic organization. Environ Microbiol 2023; 25:738-750. [PMID: 36537236 DOI: 10.1111/1462-2920.16320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022]
Abstract
Verticillium dahliae is a devastating pathogenic fungus that causes severe vascular wilts in more than 400 dicotyledonous plants. The conidiation of V. dahliae in plant vascular tissues is the key strategy for its adaptation to the nutrient-poor environment and is required for its pathogenicity. However, it remains unclear about the regulatory mechanism of conidium production of V. dahliae in vascular tissues. Here, we found that VdAsp1, encoding an inositol polyphosphate kinase, is indispensable for the pathogenicity of V. dahliae. Loss of VdAsp1 function does not affect the invasion of the host, but it impairs the colonization and proliferation in vascular tissues. The ΔVdAsp1 mutant shows defective initiation of conidiophore formation and reduced expression of genes associated with the central developmental pathway. By live-cell imaging, we observed that some of ΔVdAsp1 mutant hyphae are swollen, and microtubule arrangements at the apical region of these hyphae are disorganized. These results indicate that VdAsp1 regulates the transition from vegetative growth to asexual reproduction by modulating microtubule dynamic organization, which is essential for V. dahliae to colonize and proliferate in vascular tissues. These findings provided a potential new direction in the control of vascular wilt pathogen by targeting conidium production in vascular tissues.
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Affiliation(s)
- Juan Tian
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Mengli Pu
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, China
| | - Bin Chen
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Guangda Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Chunli Li
- Public Technology Service Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xiaxia Zhang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yanjun Yu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Zhi Wang
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, China
| | - Zhaosheng Kong
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- Shanxi Key Laboratory of Minor Crops Germplasm Innovation and Molecular Breeding, Academy of Agronomy, Shanxi Agricultural University, Taiyuan, China
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2
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Qi J, Cheng W, Gao Z, Chen Y, Shipton ML, Furkert D, Chin AC, Riley AM, Fiedler D, Potter BVL, Fu C. Itraconazole inhibits endothelial cell migration by disrupting inositol pyrophosphate-dependent focal adhesion dynamics and cytoskeletal remodeling. Biomed Pharmacother 2023; 161:114449. [PMID: 36857911 PMCID: PMC7614367 DOI: 10.1016/j.biopha.2023.114449] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 02/21/2023] [Accepted: 02/23/2023] [Indexed: 03/03/2023] Open
Abstract
The antifungal drug itraconazole has been repurposed to anti-angiogenic agent, but the mechanisms of action have been elusive. Here we report that itraconazole disrupts focal adhesion dynamics and cytoskeletal remodeling, which requires 5-diphosphoinositol 1,2,3,4,6-pentakisphosphate (5-InsP7). We find that inositol hexakisphosphate kinase 1 (IP6K1) binds Arp2 and generates 5-InsP7 to recruit coronin, a negative regulator of the Arp2/3 complex. IP6K1 also produces focal adhesion-enriched 5-InsP7, which binds focal adhesion kinase (FAK) at the FERM domain to promote its dimerization and phosphorylation. Itraconazole treatment elicits displacement of IP6K1/5-InsP7, thus augments 5-InsP7-mediated inhibition of Arp2/3 complex and reduces 5-InsP7-mediated FAK dimerization. Itraconazole-treated cells display reduced focal adhesion dynamics and actin cytoskeleton remodeling. Accordingly, itraconazole severely disrupts cell motility, an essential component of angiogenesis. These results demonstrate critical roles of IP6K1-generated 5-InsP7 in regulating focal adhesion dynamics and actin cytoskeleton remodeling and reveal functional mechanisms by which itraconazole inhibits cell motility.
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Affiliation(s)
- Ji Qi
- The province and ministry co-sponsored collaborative innovation center for medical epigenetics, Tianjin Key Laboratory of Metabolic Diseases, Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin 300070, China
| | - Weiwei Cheng
- Institute for Developmental and Regenerative Cardiovascular Medicine, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Zhe Gao
- School of Integrative Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China
| | - Yuanyuan Chen
- Institute for Developmental and Regenerative Cardiovascular Medicine, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Megan L Shipton
- Medicinal Chemistry & Drug Discovery, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - David Furkert
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Alfred C Chin
- Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY, USA
| | - Andrew M Riley
- Medicinal Chemistry & Drug Discovery, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Dorothea Fiedler
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Barry V L Potter
- Medicinal Chemistry & Drug Discovery, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Chenglai Fu
- The province and ministry co-sponsored collaborative innovation center for medical epigenetics, Tianjin Key Laboratory of Metabolic Diseases, Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin 300070, China; Institute for Developmental and Regenerative Cardiovascular Medicine, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China.
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3
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Kuenzel NA, Alcázar-Román AR, Saiardi A, Bartsch SM, Daunaraviciute S, Fiedler D, Fleig U. Inositol Pyrophosphate-Controlled Kinetochore Architecture and Mitotic Entry in S. pombe. J Fungi (Basel) 2022; 8:933. [PMID: 36135658 PMCID: PMC9506091 DOI: 10.3390/jof8090933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/26/2022] [Accepted: 08/30/2022] [Indexed: 11/16/2022] Open
Abstract
Inositol pyrophosphates (IPPs) comprise a specific class of signaling molecules that regulate central biological processes in eukaryotes. The conserved Vip1/PPIP5K family controls intracellular IP8 levels, the highest phosphorylated form of IPPs present in yeasts, as it has both inositol kinase and pyrophosphatase activities. Previous studies have shown that the fission yeast S. pombe Vip1/PPIP5K family member Asp1 impacts chromosome transmission fidelity via the modulation of spindle function. We now demonstrate that an IP8 analogue is targeted by endogenous Asp1 and that cellular IP8 is subject to cell cycle control. Mitotic entry requires Asp1 kinase function and IP8 levels are increased at the G2/M transition. In addition, the kinetochore, the conductor of chromosome segregation that is assembled on chromosomes is modulated by IP8. Members of the yeast CCAN kinetochore-subcomplex such as Mal2/CENP-O localize to the kinetochore depending on the intracellular IP8-level: higher than wild-type IP8 levels reduce Mal2 kinetochore targeting, while a reduction in IP8 has the opposite effect. As our perturbations of the inositol polyphosphate and IPP pathways demonstrate that kinetochore architecture depends solely on IP8 and not on other IPPs, we conclude that chromosome transmission fidelity is controlled by IP8 via an interplay between entry into mitosis, kinetochore architecture, and spindle dynamics.
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Affiliation(s)
- Natascha Andrea Kuenzel
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Abel R. Alcázar-Román
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Adolfo Saiardi
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, Gower St., London WC1E 6BT, UK
| | - Simon M. Bartsch
- Leibniz Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin, Germany
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Sarune Daunaraviciute
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Dorothea Fiedler
- Leibniz Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin, Germany
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Ursula Fleig
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, Universitätsstrasse 1, 40225 Düsseldorf, Germany
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4
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Rosenbach H, Walla E, Cutsail GE, Birrell JA, Pascual-Ortiz M, DeBeer S, Fleig U, Span I. The Asp1 pyrophosphatase from S. pombe hosts a [2Fe-2S] 2+ cluster in vivo. J Biol Inorg Chem 2021; 26:93-108. [PMID: 33544225 PMCID: PMC8038993 DOI: 10.1007/s00775-020-01840-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 11/29/2020] [Indexed: 11/25/2022]
Abstract
The Schizosaccharomyces pombe Asp1 protein is a bifunctional kinase/pyrophosphatase that belongs to the highly conserved eukaryotic diphosphoinositol pentakisphosphate kinase PPIP5K/Vip1 family. The N-terminal Asp1 kinase domain generates specific high-energy inositol pyrophosphate (IPP) molecules, which are hydrolyzed by the C-terminal Asp1 pyrophosphatase domain (Asp1365-920). Thus, Asp1 activities regulate the intracellular level of a specific class of IPP molecules, which control a wide number of biological processes ranging from cell morphogenesis to chromosome transmission. Recently, it was shown that chemical reconstitution of Asp1371-920 leads to the formation of a [2Fe-2S] cluster; however, the biological relevance of the cofactor remained under debate. In this study, we provide evidence for the presence of the Fe-S cluster in Asp1365-920 inside the cell. However, we show that the Fe-S cluster does not influence Asp1 pyrophosphatase activity in vitro or in vivo. Characterization of the as-isolated protein by electronic absorption spectroscopy, mass spectrometry, and X-ray absorption spectroscopy is consistent with the presence of a [2Fe-2S]2+ cluster in the enzyme. Furthermore, we have identified the cysteine ligands of the cluster. Overall, our work reveals that Asp1 contains an Fe-S cluster in vivo that is not involved in its pyrophosphatase activity.
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Affiliation(s)
- Hannah Rosenbach
- Institut Für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Eva Walla
- Lehrstuhl Für Funktionelle Genomforschung Der Mikroorganismen, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - George E Cutsail
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470, Mülheim an der Ruhr, Germany
| | - James A Birrell
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Marina Pascual-Ortiz
- Department of Biomedical Sciences, Faculty of Health Sciences, Universidad Cardenal Herrera, CEU Universities, 46113, Valencia, Spain
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Ursula Fleig
- Lehrstuhl Für Funktionelle Genomforschung Der Mikroorganismen, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany.
| | - Ingrid Span
- Institut Für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany.
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5
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Vip1 is a kinase and pyrophosphatase switch that regulates inositol diphosphate signaling. Proc Natl Acad Sci U S A 2020; 117:9356-9364. [PMID: 32303658 PMCID: PMC7196807 DOI: 10.1073/pnas.1908875117] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Inositol diphosphates (PP-IPs), also known as inositol pyrophosphates, are high-energy cellular signaling codes involved in nutrient and regulatory responses. We report that the evolutionarily conserved gene product, Vip1, possesses autonomous kinase and pyrophosphatase domains capable of synthesis and destruction of D-1 PP-IPs. Our studies provide atomic-resolution structures of the PP-IP products and unequivocally define that the Vip1 gene product is a highly selective 1-kinase and 1-pyrophosphatase enzyme whose activities arise through distinct active sites. Kinetic analyses of kinase and pyrophosphatase parameters are consistent with Vip1 evolving to modulate levels of 1-IP7 and 1,5-IP8 Individual perturbations in kinase and pyrophosphatase activities in cells result in differential effects on vacuolar morphology and osmotic responses. Analogous to the dual-functional key energy metabolism regulator, phosphofructokinase 2, Vip1 is a kinase and pyrophosphatase switch whose 1-PP-IP products play an important role in a cellular adaptation.
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6
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Lev S, Li C, Desmarini D, Sorrell TC, Saiardi A, Djordjevic JT. Fungal Kinases With a Sweet Tooth: Pleiotropic Roles of Their Phosphorylated Inositol Sugar Products in the Pathogenicity of Cryptococcus neoformans Present Novel Drug Targeting Opportunities. Front Cell Infect Microbiol 2019; 9:248. [PMID: 31380293 PMCID: PMC6660261 DOI: 10.3389/fcimb.2019.00248] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/26/2019] [Indexed: 12/17/2022] Open
Abstract
Invasive fungal pathogens cause more than 300 million serious human infections and 1.6 million deaths per year. A clearer understanding of the mechanisms by which these fungi cause disease is needed to identify novel targets for urgently needed therapies. Kinases are key components of the signaling and metabolic circuitry of eukaryotic cells, which include fungi, and kinase inhibition is currently being exploited for the treatment of human diseases. Inhibiting evolutionarily divergent kinases in fungal pathogens is a promising avenue for antifungal drug development. One such group of kinases is the phospholipase C1-dependent inositol polyphosphate kinases (IPKs), which act sequentially to transfer a phosphoryl group to a pre-phosphorylated inositol sugar (IP). This review focuses on the roles of fungal IPKs and their IP products in fungal pathogenicity, as determined predominantly from studies performed in the model fungal pathogen Cryptococcus neoformans, and compares them to what is known in non-pathogenic model fungi and mammalian cells to highlight potential drug targeting opportunities.
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Affiliation(s)
- Sophie Lev
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Cecilia Li
- Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Centre for Infectious Diseases and Microbiology-Public Health, NSW Health Pathology, Westmead Hospital, Sydney, NSW, Australia
| | - Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Tania C Sorrell
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Adolfo Saiardi
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Julianne T Djordjevic
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
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7
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Nair VS, Gu C, Janoshazi AK, Jessen HJ, Wang H, Shears SB. Inositol Pyrophosphate Synthesis by Diphosphoinositol Pentakisphosphate Kinase-1 is Regulated by Phosphatidylinositol(4,5)bisphosphate. Biosci Rep 2018; 38:BSR20171549. [PMID: 29459425 PMCID: PMC5857911 DOI: 10.1042/bsr20171549] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 02/14/2018] [Accepted: 02/17/2018] [Indexed: 11/17/2022] Open
Abstract
5-diphosphoinositol tetrakisphosphate (5-InsP7) and bisdiphosphoinositol tetrakisphosphate (InsP8) are 'energetic' inositol pyrophosphate signaling molecules that regulate bioenergetic homeostasis. Inositol pyrophosphate levels are regulated by diphosphoinositol pentakisphosphate kinases (PPIP5Ks); these are large modular proteins that host a kinase domain (which phosphorylates 5-InsP7 to InsP8), a phosphatase domain that catalyzes the reverse reaction, and a polyphosphoinositide-binding domain (PBD). Here, we describe new interactions between these three domains in the context of full-length human PPIP5K1. We determine that InsP7 kinase activity is dominant when PPIP5K1 is expressed in intact cells; in contrast, we found that InsP8 phosphatase activity prevails when the enzyme is isolated from its cellular environment. We approach a reconciliation of this disparity by showing that cellular InsP8 phosphatase activity is inhibited by C8-PtdIns(4,5)P2 (IC50 approx. 40 ìM). We recapitulate this phosphatase inhibition with natural PtdIns(4,5)P2 that was incorporated into large unilamellar vesicles. Additionally, PtdIns(4,5)P2 increases net InsP7 kinase activity 5-fold. We oftlinedemonstrate that PtdIns(4,5)P2 is not itself a phosphatase substrate; its inhibition of InsP8 phosphatase activity results from an unusual, functional overlap between the phosphatase domain and the PBD. Finally, we discuss the significance of PtdIns(4,5)P2 as a novel regulator of PPIP5K1, in relation to compartmentalization of InsP7/InsP8 signaling in vivo.
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Affiliation(s)
- Vasudha S Nair
- NIEHS, Research Triangle Park, North Carolina, United States
| | - Chunfang Gu
- NIEHS, Research Triangle Park, North Carolina, United States
| | | | | | - Huanchen Wang
- NIEHS, Research Triangle Park, North Carolina, United States
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Asp1 Bifunctional Activity Modulates Spindle Function via Controlling Cellular Inositol Pyrophosphate Levels in Schizosaccharomyces pombe. Mol Cell Biol 2018; 38:MCB.00047-18. [PMID: 29440310 DOI: 10.1128/mcb.00047-18] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 02/01/2018] [Indexed: 11/20/2022] Open
Abstract
The generation of two daughter cells with the same genetic information requires error-free chromosome segregation during mitosis. Chromosome transmission fidelity is dependent on spindle structure/function, which requires Asp1 in the fission yeast Schizosaccharomyces pombe Asp1 belongs to the diphosphoinositol pentakisphosphate kinase (PPIP5K)/Vip1 family which generates high-energy inositol pyrophosphate (IPP) molecules. Here, we show that Asp1 is a bifunctional enzyme in vivo: Asp1 kinase generates specific IPPs which are the substrates of the Asp1 pyrophosphatase. Intracellular levels of these IPPs directly correlate with microtubule stability: pyrophosphatase loss-of-function mutants raised Asp1-made IPP levels 2-fold, thus increasing microtubule stability, while overexpression of the pyrophosphatase decreased microtubule stability. Absence of Asp1-generated IPPs resulted in an aberrant, increased spindle association of the S. pombe kinesin-5 family member Cut7, which led to spindle collapse. Thus, chromosome transmission is controlled via intracellular IPP levels. Intriguingly, identification of the mitochondrion-associated Met10 protein as the first pyrophosphatase inhibitor revealed that IPPs also regulate mitochondrial distribution.
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9
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Shah A, Ganguli S, Sen J, Bhandari R. Inositol Pyrophosphates: Energetic, Omnipresent and Versatile Signalling Molecules. J Indian Inst Sci 2017; 97:23-40. [PMID: 32214696 PMCID: PMC7081659 DOI: 10.1007/s41745-016-0011-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 11/16/2016] [Indexed: 12/21/2022]
Abstract
Inositol pyrophosphates (PP-IPs) are a class of energy-rich signalling molecules found in all eukaryotic cells. These are derivatives of inositol that contain one or more diphosphate (or pyrophosphate) groups in addition to monophosphates. The more abundant and best studied PP-IPs are diphosphoinositol pentakisphosphate (IP7) and bis-diphosphoinositol tetrakisphosphate (IP8). These molecules can influence protein function by two mechanisms: binding and pyrophosphorylation. The former involves the specific interaction of a particular inositol pyrophosphate with a binding site on a protein, while the latter is a unique attribute of inositol pyrophosphates, wherein the β-phosphate moiety is transferred from a PP-IP to a pre-phosphorylated serine residue in a protein to generate pyrophosphoserine. Both these events can result in changes in the target protein’s activity, localisation or its interaction with other partners. As a consequence of their ubiquitous presence in all eukaryotic organisms and all cell types examined till date, and their ability to modify protein function, PP-IPs have been found to participate in a wide range of metabolic, developmental, and signalling pathways. This review highlights
many of the known functions of PP-IPs in the context of their temporal and spatial distribution in eukaryotic cells.
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Affiliation(s)
- Akruti Shah
- Laboratory of Cell Signalling, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana India
- Graduate Studies, Manipal University, Manipal, Karnataka India
| | - Shubhra Ganguli
- Laboratory of Cell Signalling, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana India
- Graduate Studies, Manipal University, Manipal, Karnataka India
| | - Jayraj Sen
- Laboratory of Cell Signalling, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana India
- Graduate Studies, Manipal University, Manipal, Karnataka India
| | - Rashna Bhandari
- Laboratory of Cell Signalling, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana India
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10
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Inositol Pyrophosphate Kinase Asp1 Modulates Chromosome Segregation Fidelity and Spindle Function in Schizosaccharomyces pombe. Mol Cell Biol 2016; 36:3128-3140. [PMID: 27697865 DOI: 10.1128/mcb.00330-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 09/29/2016] [Indexed: 01/08/2023] Open
Abstract
Chromosome transmission fidelity during mitosis is of critical importance for the fitness of an organism, as mistakes will lead to aneuploidy, which has a causative role in numerous severe diseases. Proper segregation of chromosomes depends on interdependent processes at the microtubule-kinetochore interface and the spindle assembly checkpoint. Here we report the discovery of a new element essential for chromosome transmission fidelity that implicates inositol pyrophosphates (IPPs) as playing a key role in this process. The protein is Asp1, the Schizosaccharomyces pombe member of the highly conserved Vip1 family. Vip1 enzymes are bifunctional: they consist of an IPP-generating kinase domain and a pyrophosphatase domain that uses such IPPs as substrates. We show that Asp1 kinase function is required for bipolar spindle formation. The absence of Asp1-generated IPPs resulted in errors in sister chromatid biorientation, a prolonged checkpoint-controlled delay of anaphase onset, and chromosome missegregation. Remarkably, expression of Asp1 variants that generated higher-than-wild-type levels of IPPs led to a faster-than-wild-type entry into anaphase A without an increase in chromosome missegregation. In fact, the chromosome transmission fidelity of a nonessential chromosome was enhanced with increased cellular IPPs. Thus, we identified an element that optimized the wild-type chromosome transmission process.
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11
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PPIP5K1 interacts with the exocyst complex through a C-terminal intrinsically disordered domain and regulates cell motility. Cell Signal 2016; 28:401-411. [PMID: 26854614 DOI: 10.1016/j.cellsig.2016.02.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 02/01/2016] [Accepted: 02/02/2016] [Indexed: 11/24/2022]
Abstract
Cellular signaling involves coordinated regulation of many events. Scaffolding proteins are crucial regulators of cellular signaling, because they are able to affect numerous events by coordinating specific interactions among multiple protein partners in the same pathway. Scaffolding proteins often contain intrinsically disordered regions (IDR) that facilitate the formation and function of distinct protein complexes. We show that PPIP5K1 contains an unusually long and evolutionarily conserved IDR. To investigate the biological role(s) of this domain, we identified interacting proteins using affinity purification coupled with mass spectrometry. Here, we report that PPIP5K1 is associated with a network of proteins that regulate vesicle-mediated transport. We further identified exocyst complex component 1 as a direct interactor with the IDR of PPIP5K1. Additionally, we report that knockdown of PPIP5K1 decreases motility of HeLa cells in a wound-healing assay. These results suggest that PPIP5K1 might play an important role in regulating function of exocyst complex in establishing cellular polarity and directional migration of cells.
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12
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Wang H, Nair VS, Holland AA, Capolicchio S, Jessen HJ, Johnson MK, Shears SB. Asp1 from Schizosaccharomyces pombe binds a [2Fe-2S](2+) cluster which inhibits inositol pyrophosphate 1-phosphatase activity. Biochemistry 2015; 54:6462-74. [PMID: 26422458 DOI: 10.1021/acs.biochem.5b00532] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Iron-sulfur (Fe-S) clusters are widely distributed protein cofactors that are vital to cellular biochemistry and the maintenance of bioenergetic homeostasis, but to our knowledge, they have never been identified in any phosphatase. Here, we describe an iron-sulfur cluster in Asp1, a dual-function kinase/phosphatase that regulates cell morphogenesis in Schizosaccharomyces pombe. Full-length Asp1, and its phosphatase domain (Asp1(371-920)), were each heterologously expressed in Escherichia coli. The phosphatase activity is exquisitely specific: it hydrolyzes the 1-diphosphate from just two members of the inositol pyrophosphate (PP-InsP) signaling family, namely, 1-InsP7 and 1,5-InsP8. We demonstrate that Asp1 does not hydrolyze either InsP6, 2-InsP7, 3-InsP7, 4-InsP7, 5-InsP7, 6-InsP7, or 3,5-InsP8. We also recorded 1-phosphatase activity in a human homologue of Asp1, hPPIP5K1, which was heterologously expressed in Drosophila S3 cells with a biotinylated N-terminal tag, and then isolated from cell lysates with avidin beads. Purified, recombinant Asp1(371-920) contained iron and acid-labile sulfide, but the stoichiometry (0.8 atoms of each per protein molecule) indicates incomplete iron-sulfur cluster assembly. We reconstituted the Fe-S cluster in vitro under anaerobic conditions, which increased the stoichiometry to approximately 2 atoms of iron and acid-labile sulfide per Asp1 molecule. The presence of a [2Fe-2S](2+) cluster in Asp1(371-920) was demonstrated by UV-visible absorption, resonance Raman spectroscopy, and electron paramagnetic resonance spectroscopy. We determined that this [2Fe-2S](2+) cluster is unlikely to participate in redox chemistry, since it rapidly degraded upon reduction by dithionite. Biochemical and mutagenic studies demonstrated that the [2Fe-2S](2+) cluster substantially inhibits the phosphatase activity of Asp1, thereby increasing its net kinase activity.
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Affiliation(s)
- Huanchen Wang
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health , 101 T. W. Alexander Drive, Research Triangle Park, North Carolina 27709, United States
| | - Vasudha S Nair
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health , 101 T. W. Alexander Drive, Research Triangle Park, North Carolina 27709, United States
| | - Ashley A Holland
- Department of Chemistry and Center for Metalloenzyme Studies, University of Georgia , Athens, Georgia 30602, United States
| | - Samanta Capolicchio
- Department of Chemistry, University of Zurich (UZH) , Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Henning J Jessen
- Department of Chemistry, University of Zurich (UZH) , Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Michael K Johnson
- Department of Chemistry and Center for Metalloenzyme Studies, University of Georgia , Athens, Georgia 30602, United States
| | - Stephen B Shears
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health , 101 T. W. Alexander Drive, Research Triangle Park, North Carolina 27709, United States
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Fungal Inositol Pyrophosphate IP7 Is Crucial for Metabolic Adaptation to the Host Environment and Pathogenicity. mBio 2015; 6:e00531-15. [PMID: 26037119 PMCID: PMC4453010 DOI: 10.1128/mbio.00531-15] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Inositol pyrophosphates (PP-IPs) comprising inositol, phosphate, and pyrophosphate (PP) are essential for multiple functions in eukaryotes. Their role in fungal pathogens has never been addressed. Cryptococcus neoformans is a model pathogenic fungus causing life-threatening meningoencephalitis. We investigate the cryptococcal kinases responsible for the production of PP-IPs (IP7/IP8) and the hierarchy of PP-IP importance in pathogenicity. Using gene deletion and inositol polyphosphate profiling, we identified Kcs1 as the major IP6 kinase (producing IP7) and Asp1 as an IP7 kinase (producing IP8). We show that Kcs1-derived IP7 is the most crucial PP-IP for cryptococcal drug susceptibility and the production of virulence determinants. In particular, Kcs1 kinase activity is essential for cryptococcal infection of mouse lungs, as reduced fungal burdens were observed in the absence of Kcs1 or when Kcs1 was catalytically inactive. Transcriptome and carbon source utilization analysis suggested that compromised growth of the KCS1 deletion strain (Δkcs1 mutant) in the low-glucose environment of the host lung is due to its inability to utilize alternative carbon sources. Despite this metabolic defect, the Δkcs1 mutant established persistent, low-level asymptomatic pulmonary infection but failed to elicit a strong immune response in vivo and in vitro and was not readily phagocytosed by primary or immortalized monocytes. Reduced recognition of the Δkcs1 cells by monocytes correlated with reduced exposure of mannoproteins on the Δkcs1 mutant cell surface. We conclude that IP7 is essential for fungal metabolic adaptation to the host environment, immune recognition, and pathogenicity. Cryptococcus neoformans is responsible for 1 million cases of AIDS-associated meningitis and ~600,000 deaths annually. Understanding cellular pathways responsible for pathogenicity might have an impact on new drug development. We characterized the inositol polyphosphate kinases Kcs1 and Asp1, which are predicted to catalyze the production of inositol pyrophosphates containing one or two diphosphate moieties (PP-IPs). Using gene deletion analysis and inositol polyphosphate profiling, we confirmed that Kcs1 and Asp1 are major IP6 and IP7 kinases, respectively. Kcs1-derived IP7, but not Asp1-derived IP8, is crucial for pathogenicity. Global expression profiling and carbon source utilization testing suggest that IP7-deficient cryptococci cannot adapt their metabolism to allow growth in the glucose-poor environment of the host lung, and consequently, fungal burdens are significantly reduced. Persistent asymptomatic Δkcs1 mutant infection correlated with decreased mannoprotein exposure on the Δkcs1 mutant surface and reduced phagocytosis. We conclude that IP7 is crucial for the metabolic adaptation of C. neoformans to the host environment and for pathogenicity.
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Pöhlmann J, Risse C, Seidel C, Pohlmann T, Jakopec V, Walla E, Ramrath P, Takeshita N, Baumann S, Feldbrügge M, Fischer R, Fleig U. The Vip1 inositol polyphosphate kinase family regulates polarized growth and modulates the microtubule cytoskeleton in fungi. PLoS Genet 2014; 10:e1004586. [PMID: 25254656 PMCID: PMC4177672 DOI: 10.1371/journal.pgen.1004586] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 07/08/2014] [Indexed: 11/19/2022] Open
Abstract
Microtubules (MTs) are pivotal for numerous eukaryotic processes ranging from cellular morphogenesis, chromosome segregation to intracellular transport. Execution of these tasks requires intricate regulation of MT dynamics. Here, we identify a new regulator of the Schizosaccharomyces pombe MT cytoskeleton: Asp1, a member of the highly conserved Vip1 inositol polyphosphate kinase family. Inositol pyrophosphates generated by Asp1 modulate MT dynamic parameters independent of the central +TIP EB1 and in a dose-dependent and cellular-context-dependent manner. Importantly, our analysis of the in vitro kinase activities of various S. pombe Asp1 variants demonstrated that the C-terminal phosphatase-like domain of the dual domain Vip1 protein negatively affects the inositol pyrophosphate output of the N-terminal kinase domain. These data suggest that the former domain has phosphatase activity. Remarkably, Vip1 regulation of the MT cytoskeleton is a conserved feature, as Vip1-like proteins of the filamentous ascomycete Aspergillus nidulans and the distantly related pathogenic basidiomycete Ustilago maydis also affect the MT cytoskeleton in these organisms. Consistent with the role of interphase MTs in growth zone selection/maintenance, all 3 fungal systems show aspects of aberrant cell morphogenesis. Thus, for the first time we have identified a conserved biological process for inositol pyrophosphates.
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Affiliation(s)
- Jennifer Pöhlmann
- Lehrstuhl für funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Carmen Risse
- Lehrstuhl für funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Constanze Seidel
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute for Applied Biosciences, Dept. of Microbiology, Karlsruhe, Germany
| | - Thomas Pohlmann
- Institut für Mikrobiologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Visnja Jakopec
- Lehrstuhl für funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Eva Walla
- Lehrstuhl für funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Pascal Ramrath
- Lehrstuhl für funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Norio Takeshita
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute for Applied Biosciences, Dept. of Microbiology, Karlsruhe, Germany
- University of Tsukuba, Faculty of Life and Environmental Sciences, Ibaraki, Tsukuba, Japan
| | - Sebastian Baumann
- Institut für Mikrobiologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Michael Feldbrügge
- Institut für Mikrobiologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Reinhard Fischer
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute for Applied Biosciences, Dept. of Microbiology, Karlsruhe, Germany
| | - Ursula Fleig
- Lehrstuhl für funktionelle Genomforschung der Mikroorganismen, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
- * E-mail:
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15
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Duressa D, Anchieta A, Chen D, Klimes A, Garcia-Pedrajas MD, Dobinson KF, Klosterman SJ. RNA-seq analyses of gene expression in the microsclerotia of Verticillium dahliae. BMC Genomics 2013; 14:607. [PMID: 24015849 PMCID: PMC3852263 DOI: 10.1186/1471-2164-14-607] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 09/04/2013] [Indexed: 11/10/2022] Open
Abstract
Background The soilborne fungus, Verticillium dahliae, causes Verticillium wilt disease in plants. Verticillium wilt is difficult to control since V. dahliae is capable of persisting in the soil for 10 to 15 years as melanized microsclerotia, rendering crop rotation strategies for disease control ineffective. Microsclerotia of V. dahliae overwinter and germinate to produce infectious hyphae that give rise to primary infections. Consequently, microsclerotia formation, maintenance, and germination are critically important processes in the disease cycle of V. dahliae. Results To shed additional light on the molecular processes that contribute to microsclerotia biogenesis and melanin synthesis in V. dahliae, three replicate RNA-seq libraries were prepared from 10 day-old microsclerotia (MS)-producing cultures of V. dahliae, strain VdLs.17 (average = 52.23 million reads), and those not producing microsclerotia (NoMS, average = 50.58 million reads). Analyses of these libraries for differential gene expression revealed over 200 differentially expressed genes, including up-regulation of melanogenesis-associated genes tetrahydroxynaphthalene reductase (344-fold increase) and scytalone dehydratase (231-fold increase), and additional genes located in a 48.8 kilobase melanin biosynthetic gene cluster of strain VdLs.17. Nearly 50% of the genes identified as differentially expressed in the MS library encode hypothetical proteins. Additional comparative analyses of gene expression in V. dahliae, under growth conditions that promote or preclude microsclerotial development, were conducted using a microarray approach with RNA derived from V. dahliae strain Dvd-T5, and from the amicrosclerotial vdh1 strain. Differential expression of selected genes observed by RNA-seq or microarray analysis was confirmed using RT-qPCR or Northern hybridizations. Conclusion Collectively, the data acquired from these investigations provide additional insight into gene expression and molecular processes that occur during MS biogenesis and maturation in V. dahliae. The identified gene products could therefore potentially represent new targets for disease control through prevention of survival structure development.
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Affiliation(s)
- Dechassa Duressa
- United States Department of Agriculture - Agricultural Research Service, Salinas, CA, USA.
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Inositol phosphate kinase Vip1p interacts with histone chaperone Asf1p in Saccharomyces cerevisiae. Mol Biol Rep 2011; 39:4989-96. [PMID: 22160571 DOI: 10.1007/s11033-011-1295-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Accepted: 11/30/2011] [Indexed: 12/25/2022]
Abstract
Histone eviction and deposition are critical steps in many nuclear processes. The histone H3/H4 chaperone Asf1p is highly conserved and is involved in DNA replication, DNA repair, and transcription. To identify the factors concerned with anti-silencing function 1 (ASF1), we purified Asf1p-associated factors from the yeast Saccharomyces cerevisiae by a GST pull-down experiment, and mass spectrometry analysis was performed. Several factors are specifically associated with Asf1p, including Vip1p. VIP1 is conserved from yeast to humans and encodes inositol hexakisphoshate and inositol heptakisphosphate kinase. Vip1p interacted with Asf1p as a dimer or in a complex with another protein(s). Deletion of VIP1 did not affect the interaction between Asf1p and other Asf1p-associated factors. An in vitro GST pull-down assay indicated a direct interaction between Asf1p and Vip1p, and the interaction between the two factors in vivo was detected by an immunoprecipitation experiment. Furthermore, genetic experiments revealed that VIP1 disruption increased sensitivity to 6-azauracil (6-AU), but not to DNA-damaging reagents in wild-type and ASF1-deleted strains. It is thought that 6-AU decreases nucleotide levels and reduces transcription elongation. These observations suggest that the association of Asf1p and Vip1p may be implicated in transcription elongation.
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17
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Asp1, a conserved 1/3 inositol polyphosphate kinase, regulates the dimorphic switch in Schizosaccharomyces pombe. Mol Cell Biol 2010; 30:4535-47. [PMID: 20624911 DOI: 10.1128/mcb.00472-10] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The ability to undergo dramatic morphological changes in response to extrinsic cues is conserved in fungi. We have used the model yeast Schizosaccharomyces pombe to determine which intracellular signal regulates the dimorphic switch from the single-cell yeast form to the filamentous invasive growth form. The S. pombe Asp1 protein, a member of the conserved Vip1 1/3 inositol polyphosphate kinase family, is a key regulator of the morphological switch via the cAMP protein kinase A (PKA) pathway. Lack of a functional Asp1 kinase domain abolishes invasive growth which is monopolar, while an increase in Asp1-generated inositol pyrophosphates (PP) increases the cellular response. Remarkably, the Asp1 kinase activity encoded by the N-terminal part of the protein is regulated negatively by the C-terminal domain of Asp1, which has homology to acid histidine phosphatases. Thus, the fine tuning of the cellular response to environmental cues is modulated by the same protein. As the Saccharomyces cerevisiae Asp1 ortholog is also required for the dimorphic switch in this yeast, we propose that Vip1 family members have a general role in regulating fungal dimorphism.
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18
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Monserrate JP, York JD. Inositol phosphate synthesis and the nuclear processes they affect. Curr Opin Cell Biol 2010; 22:365-73. [DOI: 10.1016/j.ceb.2010.03.006] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 03/03/2010] [Accepted: 03/04/2010] [Indexed: 01/30/2023]
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19
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Tsui MM, York JD. Roles of inositol phosphates and inositol pyrophosphates in development, cell signaling and nuclear processes. ACTA ACUST UNITED AC 2009; 50:324-37. [PMID: 20006638 DOI: 10.1016/j.advenzreg.2009.12.002] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Marco M Tsui
- Department of Pharmacology and Cancer Biology, Howard Hughes Medical Institute, Duke University Medical Center, Box 3813, Durham, NC 27710, USA
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20
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Reconstruction of signaling networks regulating fungal morphogenesis by transcriptomics. EUKARYOTIC CELL 2009; 8:1677-91. [PMID: 19749177 DOI: 10.1128/ec.00050-09] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Coordinated control of hyphal elongation and branching is essential for sustaining mycelial growth of filamentous fungi. In order to study the molecular machinery ensuring polarity control in the industrial fungus Aspergillus niger, we took advantage of the temperature-sensitive (ts) apical-branching ramosa-1 mutant. We show here that this strain serves as an excellent model system to study critical steps of polar growth control during mycelial development and report for the first time a transcriptomic fingerprint of apical branching for a filamentous fungus. This fingerprint indicates that several signal transduction pathways, including TORC2, phospholipid, calcium, and cell wall integrity signaling, concertedly act to control apical branching. We furthermore identified the genetic locus affected in the ramosa-1 mutant by complementation of the ts phenotype. Sequence analyses demonstrated that a single amino acid exchange in the RmsA protein is responsible for induced apical branching of the ramosa-1 mutant. Deletion experiments showed that the corresponding rmsA gene is essential for the growth of A. niger, and complementation analyses with Saccharomyces cerevisiae evidenced that RmsA serves as a functional equivalent of the TORC2 component Avo1p. TORC2 signaling is required for actin polarization and cell wall integrity in S. cerevisiae. Congruently, our microscopic investigations showed that polarized actin organization and chitin deposition are disturbed in the ramosa-1 mutant. The integration of the transcriptomic, genetic, and phenotypic data obtained in this study allowed us to reconstruct a model for cellular events involved in apical branching.
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21
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Dual functions for the Schizosaccharomyces pombe inositol kinase Ipk1 in nuclear mRNA export and polarized cell growth. EUKARYOTIC CELL 2008; 8:134-46. [PMID: 19047361 DOI: 10.1128/ec.00279-08] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The inositol 1,3,4,5,6-pentakisphosphate (IP(5)) 2-kinase (Ipk1) catalyzes the production of inositol hexakisphosphate (IP(6)) in eukaryotic cells. Previous studies have shown that IP(6) is required for efficient nuclear mRNA export in the budding yeast Saccharomyces cerevisiae. Here, we report the first functional analysis of ipk1(+) in Schizosaccharomyces pombe. S. pombe Ipk1 (SpIpk1) is unique among Ipk1 orthologues in that it harbors a novel amino (N)-terminal domain with coiled-coil structural motifs similar to those of BAR (Bin-amphiphysin-Rvs) domain proteins. Mutants with ipk1(+) deleted (ipk1Delta) had mRNA export defects as well as pleiotropic defects in polarized growth, cell morphology, endocytosis, and cell separation. The SpIpk1 catalytic carboxy-terminal domain was required to rescue these defects, and the mRNA export block was genetically linked to SpDbp5 function and, likely, IP(6) production. However, the overexpression of the N-terminal domain alone also inhibited these functions in wild-type cells. This revealed a distinct noncatalytic function for the N-terminal domain. To test for connections with other inositol polyphosphates, we also analyzed whether the loss of asp1(+) function, encoding an IP(6) kinase downstream of Ipk1, had an effect on ipk1Delta cells. The asp1Delta mutant alone did not block mRNA export, and its cell morphology, polarized growth, and endocytosis defects were less severe than those of ipk1Delta cells. Moreover, ipk1Delta asp1Delta double mutants had altered inositol polyphosphate levels distinct from those of the ipk1Delta mutant. This suggested novel roles for asp1(+) upstream of ipk1(+). We propose that IP(6) production is a key signaling linchpin for regulating multiple essential cellular processes.
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22
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Miklos I, Szilagyi Z, Watt S, Zilahi E, Batta G, Antunovics Z, Enczi K, Bähler J, Sipiczki M. Genomic expression patterns in cell separation mutants of Schizosaccharomyces pombe defective in the genes sep10 ( + ) and sep15 ( + ) coding for the Mediator subunits Med31 and Med8. Mol Genet Genomics 2007; 279:225-38. [PMID: 17922236 DOI: 10.1007/s00438-007-0296-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Accepted: 09/19/2007] [Indexed: 11/26/2022]
Abstract
Cell division is controlled by a complex network involving regulated transcription of genes and postranslational modification of proteins. The aim of this study is to demonstrate that the Mediator complex, a general regulator of transcription, is involved in the regulation of the second phase (cell separation) of cell division of the fission yeast Schizosaccharomyces pombe. In previous studies we have found that the fission yeast cell separation genes sep10 ( + ) and sep15 ( + ) code for proteins (Med31 and Med8) associated with the Mediator complex. Here, we show by genome-wide gene expression profiling of mutants defective in these genes that both Med8 and Med31 control large, partially overlapping sets of genes scattered over the entire genome and involved in diverse biological functions. Six cell separation genes controlled by the transcription factors Sep1 and Ace2 are among the target genes. Since neither sep1 ( + ) nor ace2 ( + ) is affected in the mutant cells, we propose that the Med8 and Med31 proteins act as coactivators of the Sep1-Ace2-dependent cell separation genes. The results also indicate that the subunits of Mediator may contribute to the coordination of cellular processes by fine-tuning of the expression of larger sets of genes.
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Affiliation(s)
- Ida Miklos
- Department of Genetics and Applied Microbiology, University of Debrecen, Debrecen, Hungary
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Fridy PC, Otto JC, Dollins DE, York JD. Cloning and characterization of two human VIP1-like inositol hexakisphosphate and diphosphoinositol pentakisphosphate kinases. J Biol Chem 2007; 282:30754-62. [PMID: 17690096 DOI: 10.1074/jbc.m704656200] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Eukaryotes possess numerous inositol phosphate (IP) and diphosphoinositol phosphate (PP-IPs or inositol pyrophosphates) species that act as chemical codes important for intracellular signaling pathways. Production of IP and PP-IP molecules occurs through several classes of evolutionarily conserved inositol phosphate kinases. Here we report the characterization of a human inositol hexakisphosphate (IP6) and diphosphoinositol pentakisphosphate (PP-IP5 or IP7) kinase with similarity to the yeast enzyme Vip1, a recently identified IP6/IP7 kinase (Mulugu, S., Bai, W., Fridy, P. C., Bastidas, R. J., Otto, J. C., Dollins, D. E., Haystead, T. A., Ribeiro, A. A., and York, J. D. (2007) Science 316, 106-109). Recombinant human VIP1 exhibits in vitro IP6 and IP7 kinase activities and restores IP7 synthesis when expressed in mutant yeast. Expression of human VIP1 in HEK293T cells engineered to produce high levels of IP7 results in dramatic increases in bisdiphosphoinositol tetrakisphosphate (PP2-IP4 or IP8). Northern blot analysis indicates that human VIP1 is expressed in a variety of tissues and is enriched in skeletal muscle, heart, and brain. The subcellular distribution of tagged human VIP1 is indicative of a cytoplasmic non-membrane localization pattern. We also characterized human and mouse VIP2, an additional gene product with nearly 90% similarity to VIP1 in the kinase domain, and observed both IP6 and IP7 kinase activities. Our data demonstrate that human VIP1 and VIP2 function as IP6 and IP7 kinases that act along with the IP6K/Kcs1-class of kinases to convert IP6 to IP8 in mammalian cells, a process that has been found to occur in response to various stimuli and signaling events.
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Affiliation(s)
- Peter C Fridy
- Department of Pharmacology, Duke University Medical Center, Durham, North Carolina, 27710, USA
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Mulugu S, Bai W, Fridy PC, Bastidas RJ, Otto JC, Dollins DE, Haystead TA, Ribeiro AA, York JD. A conserved family of enzymes that phosphorylate inositol hexakisphosphate. Science 2007; 316:106-9. [PMID: 17412958 DOI: 10.1126/science.1139099] [Citation(s) in RCA: 196] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Inositol pyrophosphates are a diverse group of high-energy signaling molecules whose cellular roles remain an active area of study. We report a previously uncharacterized class of inositol pyrophosphate synthase and find it is identical to yeast Vip1 and Asp1 proteins, regulators of actin-related protein-2/3 (ARP 2/3) complexes. Vip1 and Asp1 acted as enzymes that encode inositol hexakisphosphate (IP6) and inositol heptakisphosphate (IP7) kinase activities. Alterations in kinase activity led to defects in cell growth, morphology, and interactions with ARP complex members. The functionality of Asp1 and Vip1 may provide cells with increased signaling capacity through metabolism of IP6.
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Affiliation(s)
- Sashidhar Mulugu
- Howard Hughes Medical Institute, Department of Pharmacology and Cancer Biology, Duke University Medical Center, DUMC 3813, Durham, NC 27710, USA
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Gachet Y, Hyams JS. Endocytosis in fission yeast is spatially associated with the actin cytoskeleton during polarised cell growth and cytokinesis. J Cell Sci 2005; 118:4231-42. [PMID: 16141239 DOI: 10.1242/jcs.02530] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the fission yeast, Schizosaccharomyces pombe, uptake of the fluorescent styryl dye FM4-64 via the endocytic pathway to the vacuole was localised to the poles of growing, interphase cells and to the cell equator during cell division, regions of cell wall deposition that are rich in actin. When the pattern of growth or the plane of cytokinesis was altered, the relationship between the actin cytoskeleton and the site of endocytosis was maintained. Transfer of the label to the vacuolar membrane was dependent upon the Rab GTPase Ypt7 and, hence, vesicle fusion. Endocytic vesicles transiently colocalised with actin patches and endocytosis was inhibited in mutants that affected actin patch integrity and by the actin inhibitor latrunculin A. Concentrations of latrunculin that removed actin cables but left patches unaffected had no effect on endocytosis at the poles, but abolished endocytosis at the cell equator. Equatorial, but not polar, endocytosis was also inhibited in cells lacking the formin For3 (which have selectively destabilised actin cables), in mutants of the exocyst complex and in cells treated with brefeldin A. Differential effects on endocytosis at the cell poles and equator were also observed in the actin mutant cps8 and the Arp2/3 complex mutant arp2. The redirection of endocytosis from the cell poles to the cell equator in M phase coincided with the anaphase separation of sister chromatids and was abolished in the septation initiation network (SIN) mutants cdc7, sid1 and sid2, demonstrating that the spatial reorganisation of the endocytic pathway in the S. pombe cell cycle requires a functional SIN pathway. We conclude that endocytosis in fission yeast has two distinct components, both of which are actin-based, but which are mechanistically distinct, as well as being spatially and temporally separated in the S. pombe cell cycle.
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Affiliation(s)
- Yannick Gachet
- Department of Biology, University College London, Gower Street, London WC1E 6BT, UK
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Weeks ME, Sinclair J, Jacob RJ, Saxton MJ, Kirby S, Jones J, Waterfield MD, Cramer R, Timms JF. Stress-induced changes in theSchizosaccharomyces pombe proteome using two-dimensional difference gel electrophoresis, mass spectrometry and a novel integrated robotics platform. Proteomics 2005; 5:1669-85. [PMID: 15789347 DOI: 10.1002/pmic.200401241] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Robotic and manual methods have been used to obtain identification of significantly changing proteins regulated when Schizosaccharomyces pombe is exposed to oxidative stress. Differently treated S. pombe cells were lysed, labelled with CyDye and analysed by two-dimensional difference gel electrophoresis. Gel images analysed off-line, using the DeCyder image analysis software [GE Healthcare, Amersham, UK] allowed selection of significantly regulated proteins. Proteins displaying differential expression were excised robotically for manual digestion and identified by matrix-assisted laser desorption/ionisation - mass spectrometry (MALDI-MS). Additionally the same set of proteins displaying differential expression were automatically cut and digested using a prototype robotic platform. Automated MALDI-MS, peak label assignment and database searching were utilised to identify as many proteins as possible. The results achieved by the robotic system were compared to manual methods. The identification of all significantly altered proteins provides an annotated peroxide stress-related proteome that can be used as a base resource against which other stress-induced proteomic changes can be compared.
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Affiliation(s)
- Mark E Weeks
- Ludwig Institute for Cancer Research, Gower Street, London, UK.
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Avidan N, Tamary H, Dgany O, Cattan D, Pariente A, Thulliez M, Borot N, Moati L, Barthelme A, Shalmon L, Krasnov T, Ben-Asher E, Olender T, Khen M, Yaniv I, Zaizov R, Shalev H, Delaunay J, Fellous M, Lancet D, Beckmann JS. CATSPER2, a human autosomal nonsyndromic male infertility gene. Eur J Hum Genet 2003; 11:497-502. [PMID: 12825070 DOI: 10.1038/sj.ejhg.5200991] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
In the course of positional cloning of the Congenital Dyserythropoietic Anemia type I (CDAI) [MIM 224120] gene on 15q15.1-15.3, we examined a family of French origin, in which the propositus suffered from asthenoteratozoospermia and nonsyndromic deafness in addition to CDAI. Two of his brothers had a similar phenotype. All three siblings were homozygous carriers of the CDA1 mutation as well as of a distally located approximately 70 kb deletion of the proximal copy of a 106 kb tandem repeat on chromosome 15q15. These repeats encode four genes whose distal copies may be considered pseudogenes. Lack of functional stereocilin and CATSPER2 (a voltage-gate cation channel expressed specifically in spermatozoa) may explain the observed deafness and male infertility phenotypes. To the best of our knowledge, the involvement of CATSPER2 in asthenoteratozoospermia is the first description of a human autosomal gene defect associated with nonsyndromic male infertility.
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Affiliation(s)
- Nili Avidan
- Department of Molecular Genetics, The Crown Human Genome Center, The Weizmann Institute of Science, Rehovot 76100, Israel
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Routhier EL, Burn TC, Abbaszade I, Summers M, Albright CF, Prendergast GC. Human BIN3 complements the F-actin localization defects caused by loss of Hob3p, the fission yeast homolog of Rvs161p. J Biol Chem 2001; 276:21670-7. [PMID: 11274158 DOI: 10.1074/jbc.m101096200] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The BAR adaptor proteins encoded by the RVS167 and RVS161 genes from Saccharomyces cerevisiae form a complex that regulates actin, endocytosis, and viability following starvation or osmotic stress. In this study, we identified a human homolog of RVS161, termed BIN3 (bridging integrator-3), and a Schizosaccharomyces pombe homolog of RVS161, termed hob3+ (homolog of Bin3). In human tissues, the BIN3 gene was expressed ubiquitously except for brain. S. pombe cells lacking Hob3p were often multinucleate and characterized by increased amounts of calcofluor-stained material and mislocalized F-actin. For example, while wild-type cells localized F-actin to cell ends during interphase, hob3Delta mutants had F-actin patches distributed randomly around the cell. In addition, medial F-actin rings were rarely found in hob3Delta mutants. Notably, in contrast to S. cerevisiae rvs161Delta mutants, hob3Delta mutants showed no measurable defects in endocytosis or response to osmotic stress, yet hob3+ complemented the osmosensitivity of a rvs161Delta mutant. BIN3 failed to rescue the osmosensitivity of rvs161Delta, but the actin localization defects of hob3Delta mutants were completely rescued by BIN3 and partially rescued by RVS161. These findings suggest that hob3+ and BIN3 regulate F-actin localization, like RVS161, but that other roles for this gene have diverged somewhat during evolution.
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Affiliation(s)
- E L Routhier
- Cancer Research Group, DuPont Pharmaceuticals Company, Glenolden Laboratory, Glenolden, Pennsylvania 19036, USA
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