1
|
Stochaj U. Yeast profilin mutants inhibit classical nuclear import and alter the balance between actin and tubulin levels. Biochem Cell Biol 2024; 102:206-212. [PMID: 38048555 DOI: 10.1139/bcb-2023-0223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2023] Open
Abstract
Profilin is a small protein that controls actin polymerization in yeast and higher eukaryotes. In addition, profilin has emerged as a multifunctional protein that contributes to other processes in multicellular organisms. This study focuses on profilin (Pfy1) in the budding yeast Saccharomyces cerevisiae. The primary sequences of yeast Pfy1 and its metazoan orthologs diverge vastly. However, structural elements of profilin are conserved among different species. To date, the full spectrum of Pfy1 functions has yet to be defined. The current work explores the possible involvement of yeast profilin in nuclear protein import. To this end, a panel of well-characterized yeast profilin mutants was evaluated. The experiments demonstrate that yeast profilin (i) regulates nuclear protein import, (ii) determines the subcellular localization of essential nuclear transport factors, and (iii) controls the relative abundance of actin and tubulin. Together, these results define yeast profilin as a moonlighting protein that engages in multiple essential cellular activities.
Collapse
Affiliation(s)
- Ursula Stochaj
- Department of Physiology, McGill University, Montreal, QC H3G 1Y6, Canada
- Quantitative Life Sciences Program, McGill University, Montreal, QC H3G 1Y6, Canada
| |
Collapse
|
2
|
Asakawa H, Yang HJ, Hiraoka Y, Haraguchi T. Virtual Nuclear Envelope Breakdown and Its Regulators in Fission Yeast Meiosis. Front Cell Dev Biol 2016; 4:5. [PMID: 26870731 PMCID: PMC4735346 DOI: 10.3389/fcell.2016.00005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 01/15/2016] [Indexed: 11/24/2022] Open
Abstract
Ran, a small GTPase, is required for the spindle formation and nuclear envelope (NE) formation. After NE breakdown (NEBD) during mitosis in metazoan cells, the Ran-GTP gradient across the NE is lost and Ran-GTP becomes concentrated around chromatin, thus affecting the stability of microtubules and promoting the assembly of spindle microtubules and segregation of chromosomes. Mitosis in which chromosomes are segregated subsequent to NEBD is called “open mitosis.” In contrast, many fungi undergo a process termed “closed mitosis” in which chromosome segregation and spindle formation occur without NEBD. Although the fission yeast Schizosaccharomyces pombe undergoes a closed mitosis, it exhibits a short period during meiosis (anaphase of the second meiosis; called “anaphase II”) when nuclear and cytoplasmic proteins are mixed in the presence of intact NE and nuclear pore complexes (NPC). This “virtual” nuclear envelope breakdown (vNEBD) involves changes in the localization of RanGAP1, an activator of Ran-GTP hydrolysis. Recently, Nup132, a component of the structural core Nup107-160 subcomplex of the NPC, has been shown to be involved in the maintenance of the nuclear cytoplasmic barrier in yeast meiosis. In this review, we highlight the possible roles of RanGAP1 and Nup132 in vNEBD and discuss the biological significance of vNEBD in S. pombe meiosis.
Collapse
Affiliation(s)
- Haruhiko Asakawa
- Graduate School of Frontier Biosciences, Osaka University Suita, Japan
| | - Hui-Ju Yang
- Graduate School of Frontier Biosciences, Osaka University Suita, Japan
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka UniversitySuita, Japan; Cell Biology Group, Advanced ICT Research Institute Kobe, National Institute of Information and Communications TechnologyKobe, Japan; Graduate School of Science, Department of Biology, Osaka UniversityToyonaka, Japan
| | - Tokuko Haraguchi
- Graduate School of Frontier Biosciences, Osaka UniversitySuita, Japan; Cell Biology Group, Advanced ICT Research Institute Kobe, National Institute of Information and Communications TechnologyKobe, Japan; Graduate School of Science, Department of Biology, Osaka UniversityToyonaka, Japan
| |
Collapse
|
3
|
Ohtsu M, Shibata Y, Ojika M, Tamura K, Hara-Nishimura I, Mori H, Kawakita K, Takemoto D. Nucleoporin 75 is involved in the ethylene-mediated production of phytoalexin for the resistance of Nicotiana benthamiana to Phytophthora infestans. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:1318-30. [PMID: 25122483 DOI: 10.1094/mpmi-06-14-0181-r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Mature Nicotiana benthamiana shows stable resistance to the oomycete pathogen Phytophthora infestans. Induction of phytoalexin (capsidiol) production is essential for the resistance, which is upregulated via a mitogen-activated protein kinase (MAPK) cascade (NbMEK2-WIPK/SIPK) followed by ethylene signaling. In this study, NbNup75 (encodes a nuclear pore protein Nucleoporin75) was identified as an essential gene for resistance of N. benthamiana to P. infestans. In NbNup75-silenced plants, initial events of elicitor-induced responses such as phosphorylation of MAPK and expression of defense-related genes were not affected, whereas induction of later defense responses such as capsidiol production and cell death induction was suppressed or delayed. Ethylene production induced by either INF1 or NbMEK2 was reduced in NbNup75-silenced plants, whereas the expression of NbEAS (a gene for capsidiol biosynthesis) induced by ethylene was not affected, indicating that Nup75 is required for the induction of ethylene production but not for ethylene signaling. Given that nuclear accumulation of polyA RNA was increased in NbNup75-silenced plants, efficient export of mRNA from nuclei via nuclear pores would be important for the timely upregulation of defense responses. Collectively, Nup75 is involved in the induction of a later stage of defense responses, including the ethylene-mediated production of phytoalexin for the resistance of N. benthamiana to P. infestans.
Collapse
|
4
|
Wiedner SD, Burnum KE, Pederson LM, Anderson LN, Fortuin S, Chauvigné-Hines LM, Shukla AK, Ansong C, Panisko EA, Smith RD, Wright AT. Multiplexed activity-based protein profiling of the human pathogen Aspergillus fumigatus reveals large functional changes upon exposure to human serum. J Biol Chem 2012; 287:33447-59. [PMID: 22865858 PMCID: PMC3460446 DOI: 10.1074/jbc.m112.394106] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 07/27/2012] [Indexed: 11/06/2022] Open
Abstract
Environmental adaptability is critical for survival of the fungal human pathogen Aspergillus fumigatus in the immunocompromised host lung. We hypothesized that exposure of the fungal pathogen to human serum would lead to significant alterations to the organism's physiology, including metabolic activity and stress response. Shifts in functional pathway and corresponding enzyme reactivity of A. fumigatus upon exposure to the human host may represent much needed prognostic indicators of fungal infection. To address this, we employed a multiplexed activity-based protein profiling (ABPP) approach coupled to quantitative mass spectrometry-based proteomics to measure broad enzyme reactivity of the fungus cultured with and without human serum. ABPP showed a shift from aerobic respiration to ethanol fermentation and utilization over time in the presence of human serum, which was not observed in serum-free culture. Our approach provides direct insight into this pathogen's ability to survive, adapt, and proliferate. Additionally, our multiplexed ABPP approach captured a broad swath of enzyme reactivity and functional pathways and provides a method for rapid assessment of the A. fumigatus response to external stimuli.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | - Ellen A. Panisko
- the Chemical and Biological Processes Development Group, Pacific Northwest National Laboratory, Richland, Washington 99352
| | | | | |
Collapse
|
5
|
González-Aguilera C, Askjaer P. Dissecting the NUP107 complex: multiple components and even more functions. Nucleus 2012; 3:340-8. [PMID: 22713280 DOI: 10.4161/nucl.21135] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The Nuclear Pore Complex (NPC) is a fascinating structure whose functional relevance and complexity attract significant interest. Within the NPC, several different subcomplexes interact with each other to form a highly conserved and stable structure. One of these subcomplexes is the NUP107 complex, constituted by 7-9 members. A wide variety of functions have been ascribed to the NUP107 complex, ranging from NPC assembly to mRNA export to cell differentiation. Recently, genetic dissection of the NUP107 complex has provided novel insight to the assembly of the complex and has, moreover, revealed an unexpected connection with the mitotic spindle assembly checkpoint protein MAD1.
Collapse
Affiliation(s)
- Cristina González-Aguilera
- Centro Andaluz de Biología del Desarrollo (CABD), Consejo Superior de Investigaciones Científicas, Universidad Pablo de Olavide, Seville, Spain
| | | |
Collapse
|
6
|
Sarma NJ, Buford TD, Haley T, Barbara-Haley K, Santangelo GM, Willis KA. The nuclear pore complex mediates binding of the Mig1 repressor to target promoters. PLoS One 2011; 6:e27117. [PMID: 22110603 PMCID: PMC3215702 DOI: 10.1371/journal.pone.0027117] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 10/11/2011] [Indexed: 12/22/2022] Open
Abstract
All eukaryotic cells alter their transcriptional program in response to the sugar glucose. In Saccharomyces cerevisiae, the best-studied downstream effector of this response is the glucose-regulated repressor Mig1. We show here that nuclear pore complexes also contribute to glucose-regulated gene expression. NPCs participate in glucose-responsive repression by physically interacting with Mig1 and mediating its function independently of nucleocytoplasmic transport. Surprisingly, despite its abundant presence in the nucleus of glucose-grown nup120Δ or nup133Δ cells, Mig1 has lost its ability to interact with target promoters. The glucose repression defect in the absence of these nuclear pore components therefore appears to result from the failure of Mig1 to access its consensus recognition sites in genomic DNA. We propose that the NPC contributes to both repression and activation at the level of transcription.
Collapse
Affiliation(s)
- Nayan J. Sarma
- Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi, United States of America
| | - Thomas D. Buford
- Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi, United States of America
| | - Terry Haley
- Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi, United States of America
| | - Kellie Barbara-Haley
- Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi, United States of America
| | - George M. Santangelo
- Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi, United States of America
| | - Kristine A. Willis
- Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi, United States of America
| |
Collapse
|
7
|
Liu Z, Matsuoka S, Enoki A, Yamamoto T, Furukawa K, Yamasaki Y, Nishida Y, Sugiyama S. Negative modulation of bone morphogenetic protein signaling by Dullard during wing vein formation in Drosophila. Dev Growth Differ 2011; 53:822-41. [PMID: 21790556 DOI: 10.1111/j.1440-169x.2011.01289.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Studies in Xenopus have shown that the C-terminal domain phosphatase-like domain (CPD) phosphatase Dullard is essential for proper neural development via inhibition of bone morphogenetic protein (BMP) signaling receptors. In contrast, the orthologous budding yeast Nem1 and human Dullard have been shown to dephosphorylate the phosphatidate phosphatases yeast Smp2/Pah1 and human Lipin, and the relationship between phospholipid metabolism and BMP signaling remain unsolved. Here we report evidence that the Dullard-Lipin phosphatase cascade in Drosophila can regulate BMP signaling, most likely by affecting the function of the nuclear envelope. Manipulating expression levels of either the Drosophila Dullard gene, d-dullard (ddd) or the Lipin gene, DmLpin affected wing vein formation in a manner suggesting a negative effect on BMP signaling. Furthermore, both genes exhibit genetic interaction with BMP signaling pathway components, and can affect the levels of phosphorylated-Mothers against dpp (p-Mad). Although changing ddd expression levels did not have an obvious effect on overall nuclear envelope morphology as has been shown for yeast nem1, the nuclear import machinery components Importin-β and RanGAP were mislocalized and membrane lipid staining was altered in cells overexpressing ddd. Considering the known genetic interaction between Nup84 complex nucleoporins and nem1 in yeast, and the recently reported requirement for components from the orthologous nucleoporin complex in the nuclear translocation of Drosophila Mad (Chen & Xu 2010), it is likely that the role of Drosophila Dullard in regulating membrane lipid homeostasis is conserved and is critical for normal BMP signaling.
Collapse
Affiliation(s)
- Ziguang Liu
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Japan
| | | | | | | | | | | | | | | |
Collapse
|
8
|
Whittle JRR, Schwartz TU. Architectural nucleoporins Nup157/170 and Nup133 are structurally related and descend from a second ancestral element. J Biol Chem 2009; 284:28442-28452. [PMID: 19674973 PMCID: PMC2788893 DOI: 10.1074/jbc.m109.023580] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Revised: 08/03/2009] [Indexed: 11/06/2022] Open
Abstract
The nuclear pore complex (NPC) constitutes one of the largest protein assemblies in the eukaryotic cell and forms the exclusive gateway to the nucleus. The stable, approximately 15-20-MDa scaffold ring of the NPC is built from two multiprotein complexes arranged around a central 8-fold axis. Here we present crystal structures of two large architectural units, yNup170(979-1502) and hNup107(658-925) x hNup133(517-1156), each a constituent of one of the two multiprotein complexes. Conservation of domain arrangement and of tertiary structure suggests that Nup157/170 and Nup133 derived from a common ancestor. Together with the previously established ancestral coatomer element (ACE1), these two elements constitute the major alpha-helical building blocks of the NPC scaffold and define its branched, lattice-like architecture, similar to vesicle coats like COPII. We hypothesize that the extant NPC evolved early during eukaryotic evolution from a rudimentary structure composed of several identical copies of a few ancestral elements, later diversified and specified by gene duplication.
Collapse
Affiliation(s)
- James R R Whittle
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Thomas U Schwartz
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139.
| |
Collapse
|
9
|
Kim KY, Shin YK, Kang KC, Yoo JS, Kim JH, Paik YK. Proteomic profiling of yeast- and hyphal-specific responses of Candida albicans to the antifungal agent, HWY-289. Proteomics Clin Appl 2009; 3:452-61. [PMID: 21136971 DOI: 10.1002/prca.200800081] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Virulence of Candida albicans is attributable to its unique dimorphic transition from nonpathogenic yeast cells to pathogenic hyphal cells. We previously discovered a novel antifungal agent, known as HWY-289. To characterize the mechanism underlying HWY-289 antifungal activity, we performed 2-DE to identify proteins that were differentially expressed during yeast-to-hyphal transition and in response to HWY-289. Twenty-four differentially expressed protein spots were identified in HWY-289-treated yeast. Most differentially expressed proteins were involved in carbohydrate-derived energy metabolism, cellular detoxification, and antioxidant defenses. Two proteins were involved in cell cycle regulation and DNA processing, and both were downregulated by HWY-289, suggesting that this agent might promote cell death by weakening cellular defense systems. HWY-289 inhibited yeast-to-hyphal transition in a dose-dependent manner. 2-DE analysis of hyphae uncovered several proteins that were induced during yeast-to-hyphal transition. Of these, aconitase and phosphatidylinositol transfer protein were downregulated by HWY-289, suggesting that they mediate the antifungal effects of HWY-289. Finally, RT-PCR analysis revealed that HWY-289 induced expression of three RAS-related genes (CcCST20, CaHST7, and CaCPH1) in yeast cells, but suppressed their expression in hyphae. Thus, the antifungal action of HWY-289 may be attributable to its ability to disrupt prohyphal RAS signaling.
Collapse
Affiliation(s)
- Ki-Young Kim
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei Proteome Research Center and Biomedical Proteome Research Center, Yonsei University, Sudaemoon-ku, Seoul, Korea; Current address: Department of Biochemistry and Molecular Biology, Johns Hopkins University, 615 N. Wolfe Street, Room W8118, Baltimore, MD 21205, USA
| | | | | | | | | | | |
Collapse
|
10
|
Biotinoyl domain of human acetyl-CoA carboxylase: Structural insights into the carboxyl transfer mechanism. Proteins 2008; 72:613-24. [DOI: 10.1002/prot.21952] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
11
|
Tehlivets O, Scheuringer K, Kohlwein SD. Fatty acid synthesis and elongation in yeast. Biochim Biophys Acta Mol Cell Biol Lipids 2007; 1771:255-70. [PMID: 16950653 DOI: 10.1016/j.bbalip.2006.07.004] [Citation(s) in RCA: 298] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2006] [Revised: 07/14/2006] [Accepted: 07/17/2006] [Indexed: 12/30/2022]
Abstract
Fatty acids are essential compounds in the cell. Since the yeast Saccharomyces cerevisiae does not feed typically on fatty acids, cellular function and growth relies on endogenous synthesis. Since all cellular organelles are involved in--or dependent on--fatty acid synthesis, multiple levels of control may exist to ensure proper fatty acid composition and homeostasis. In this review, we summarize what is currently known about enzymes involved in cellular fatty acid synthesis and elongation, and discuss potential links between fatty acid metabolism, physiology and cellular regulation.
Collapse
Affiliation(s)
- Oksana Tehlivets
- Institute of Molecular Biosciences, University of Graz, A8010 Graz, Austria
| | | | | |
Collapse
|
12
|
Quan X, Tsoulos P, Kuritzky A, Zhang R, Stochaj U. The carrier Msn5p/Kap142p promotes nuclear export of the hsp70 Ssa4p and relocates in response to stress. Mol Microbiol 2006; 62:592-609. [PMID: 17020589 DOI: 10.1111/j.1365-2958.2006.05395.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cytoplasmic hsp70s like yeast Ssa4p shuttle between nucleus and cytoplasm under normal growth conditions but accumulate in nuclei upon stress. This nuclear accumulation is only transient, and Ssa4p relocates to the cytoplasm when cells recover. We show here that Ssa4p nuclear export is independent of Xpol/Crm1 and identify the importin-beta family member Msn5p/Kap142p as the exporter for Ssa4p. In growing cells and in vitro, Msn5p and Ssa4p generate genuine export complexes that require Ran/Gsp1p-GTP. Furthermore, nucleoporin Nup82p, which plays a role in Msn5p-mediated transport, is necessary for efficient export of Ssa4p. In living cells, stress not only regulates Ssa4p localization, but also controls the distribution of Msn5p. Msn5p is concentrated in nuclei of unstressed cells, but appears in the cytoplasm upon exposure to ethanol, heat, starvation or severe oxidative stress. In addition, growth on non-fermentable carbon sources relocates a portion of Msn5p to the cytoplasm and leads to a partial nuclear accumulation of Ssa4p. Taken together, growth and stress conditions that localize the transporter Msn5p to the cytoplasm also induce the nuclear accumulation of its cargo Ssa4p.
Collapse
Affiliation(s)
- XinXin Quan
- Department of Physiology, McGill University, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada
| | | | | | | | | |
Collapse
|
13
|
Kanamori N, Madsen LH, Radutoiu S, Frantescu M, Quistgaard EMH, Miwa H, Downie JA, James EK, Felle HH, Haaning LL, Jensen TH, Sato S, Nakamura Y, Tabata S, Sandal N, Stougaard J. A nucleoporin is required for induction of Ca2+ spiking in legume nodule development and essential for rhizobial and fungal symbiosis. Proc Natl Acad Sci U S A 2006; 103:359-64. [PMID: 16407163 PMCID: PMC1326171 DOI: 10.1073/pnas.0508883103] [Citation(s) in RCA: 301] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nuclear-cytoplasmic partitioning and traffic between cytoplasmic and nuclear compartments are fundamental processes in eukaryotic cells. Nuclear pore complexes mediate transport of proteins, RNAs and ribonucleoprotein particles in and out of the nucleus. Here we present positional cloning of a plant nucleoporin gene, Nup133, essential for a symbiotic signal transduction pathway shared by Rhizobium bacteria and mycorrhizal fungi. Mutation of Nup133 results in a temperature sensitive nodulation deficient phenotype and absence of mycorrhizal colonization. Root nodules developing with reduced frequency at permissive temperatures are ineffective and electron microscopy show that Rhizobium bacteria are not released from infection threads. Measurement of ion fluxes using a calcium-sensitive dye show that Nup133 is required for the Ca2+ spiking normally detectable within minutes after application of purified rhizobial Nod-factor signal molecules to root hairs. Localization of NUP133 in the nuclear envelope of root cells and root hair cells shown with enhanced yellow fluorescent protein fusion proteins suggests a novel role for NUP133 nucleoporins in a rapid nuclear-cytoplasmic communication after host-plant recognition of symbiotic microbes. Our results identify a component of an intriguing signal process requiring interaction at the cell plasma membrane and at intracellular nuclear and plastid organelle-membranes to induce a second messenger.
Collapse
Affiliation(s)
- Norihito Kanamori
- Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10 and C.F. Møllers Vej Bldg 130, 8000 Aarhus C, Denmark
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Loeillet S, Palancade B, Cartron M, Thierry A, Richard GF, Dujon B, Doye V, Nicolas A. Genetic network interactions among replication, repair and nuclear pore deficiencies in yeast. DNA Repair (Amst) 2005; 4:459-68. [PMID: 15725626 DOI: 10.1016/j.dnarep.2004.11.010] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2004] [Accepted: 11/25/2004] [Indexed: 10/25/2022]
Abstract
The yeast RAD27 gene encodes a functional homolog of the mammalian FEN1 protein, a structure-specific endo/exonuclease which plays an important role in DNA replication and repair. Previous genetic interaction studies, including a synthetic genetic array (SGA) analysis, showed that the survival of rad27Delta cells requires several DNA metabolic processes, in particular those mediated by all members of the Rad52-dependent recombinational repair pathway. Here, we report the results of our SGA analysis of the collection of non-essential yeast genes against the rad27Delta mutation, which resulted in the identification of a novel synthetic lethal interaction conferred by mutations affecting the Nup84 nuclear pore subcomplex (nup133Delta, nup120Delta and nup84Delta). Additional screens showed that all Rad52 group genes are required for the survival of the nup133Delta and nup120Delta mutants, which are defective in nuclear pore distribution and mRNA export, but not of the nup133DeltaN mutant, which is solely defective in pore distribution. This requirement for the DNA double-strand break (DSB) repair pathway is consistent with the observation that, like rad27Delta, the nup133Delta, nup120Delta and nup84Delta mutants are sensitive to methyl methanesulfonate (MMS). Furthermore, nup133Delta cells exhibit an increased number of spontaneous DNA repair foci containing Rad52. Altogether, these data suggest that the pathological interactions between the rad27Delta and specific nupDelta mutations result from the accumulation of unrepaired DNA damages.
Collapse
Affiliation(s)
- Sophie Loeillet
- Institut Curie, Section de Recherche, UMR144 Centre National de la Recherche Scientifique, Génétique Moléculaire de la Recombinaison, 26 rue d'Ulm, 75248 Paris Cedex 05, France
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Baï SW, Rouquette J, Umeda M, Faigle W, Loew D, Sazer S, Doye V. The fission yeast Nup107-120 complex functionally interacts with the small GTPase Ran/Spi1 and is required for mRNA export, nuclear pore distribution, and proper cell division. Mol Cell Biol 2004; 24:6379-92. [PMID: 15226438 PMCID: PMC434257 DOI: 10.1128/mcb.24.14.6379-6392.2004] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have characterized Schizosaccharomyces pombe open reading frames encoding potential orthologues of constituents of the evolutionarily conserved Saccharomyces cerevisiae Nup84 vertebrate Nup107-160 nuclear pore subcomplex, namely Nup133a, Nup133b, Nup120, Nup107, Nup85, and Seh1. In spite of rather weak sequence conservation, in vivo analyses demonstrated that these S. pombe proteins are localized at the nuclear envelope. Biochemical data confirmed the organization of these nucleoporins within conserved complexes. Although examination of the S. cerevisiae and S. pombe deletion mutants revealed different viability phenotypes, functional studies indicated that the involvement of this complex in nuclear pore distribution and mRNA export has been conserved between these highly divergent yeasts. Unexpectedly, microscopic analyses of some of the S. pombe mutants revealed cell division defects at the restrictive temperature (abnormal septa and mitotic spindles and chromosome missegregation) that were reminiscent of defects occurring in several S. pombe GTPase Ran (Ran(Sp))/Spi1 cycle mutants. Furthermore, deletion of nup120 moderately altered the nuclear location of Ran(Sp)/Spi1, whereas overexpression of a nonfunctional Ran(Sp)/Spi1-GFP allele was specifically toxic in the Deltanup120 and Deltanup133b mutant strains, indicating a functional and genetic link between constituents of the S. pombe Nup107-120 complex and of the Ran(Sp)/Spi1 pathway.
Collapse
|
16
|
Quan X, Rassadi R, Rabie B, Matusiewicz N, Stochaj U. Regulated nuclear accumulation of the yeast hsp70 Ssa4p in ethanol-stressed cells is mediated by the N-terminal domain, requires the nuclear carrier Nmd5p and protein kinase C. FASEB J 2004; 18:899-901. [PMID: 15001563 DOI: 10.1096/fj.03-0947fje] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cytoplasmic proteins of the hsp70/hsc70 family redistribute in cells that have been exposed to stress. As such, the hsp70 Ssa4p of the budding yeast S. cerevisiae accumulates in nuclei when cells are treated with ethanol, whereas classical nuclear import is inhibited under these conditions. The N-terminal domain of Ssa4p, which is lacking a classical NLS, mediates nuclear accumulation upon ethanol exposure. Concentration of the Ssa4p N-terminal segment in nuclei is reversible, as the protein relocates to the cytoplasm when cells recover. Mutant analysis demonstrates that the small GTPase Gsp1p and GTPase-modulating factors are required to accumulate Ssa4p in nuclei upon ethanol stress. Moreover, we have identified the importin-beta family member Nmd5p as the nuclear carrier for Ssa4p. Ethanol treatment significantly increases the formation of import complexes containing Nmd5p and the N-terminal Ssa4p domain. Likewise, docking of the carrier Nmd5p at the nuclear pore is enhanced by ethanol. Furthermore, we show that the stressed-induced nuclear accumulation of Ssa4p depends on signaling through protein kinase C and requires sensors of the cell integrity pathway.
Collapse
Affiliation(s)
- Xinxin Quan
- Physiology Department, McGill University, Montreal, PQ, Canada
| | | | | | | | | |
Collapse
|