1
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Félix-Pérez T, Mora-García M, Rebolloso-Gómez Y, DelaGarza-Varela A, Castro-Velázquez G, Peña-Gómez SG, Riego-Ruiz L, Sánchez-Olea R, Calera MR. Translation initiation factor eIF1A rescues hygromycin B sensitivity caused by deleting the carboxy-terminal tail in the GPN-loop GTPase Npa3. FEBS J 2024; 291:2191-2208. [PMID: 38431777 DOI: 10.1111/febs.17106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 12/20/2023] [Accepted: 02/20/2024] [Indexed: 03/05/2024]
Abstract
The essential yeast protein GPN-loop GTPase 1 (Npa3) plays a critical role in RNA polymerase II (RNAPII) assembly and subsequent nuclear import. We previously identified a synthetic lethal interaction between a mutant lacking the carboxy-terminal 106-amino acid tail of Npa3 (npa3ΔC) and a bud27Δ mutant. As the prefoldin-like Bud27 protein participates in ribosome biogenesis and translation, we hypothesized that Npa3 may also regulate these biological processes. We investigated this proposal by using Saccharomyces cerevisiae strains episomally expressing either wild-type Npa3 or hypomorphic mutants (Npa3ΔC, Npa3K16R, and Npa3G70A). The Npa3ΔC mutant fully supports RNAPII nuclear localization and activity. However, the Npa3K16R and Npa3G70A mutants only partially mediate RNAPII nuclear targeting and exhibit a higher reduction in Npa3 function. Cell proliferation in these strains displayed an increased sensitivity to protein synthesis inhibitors hygromycin B and geneticin/G418 (npa3G70A > npa3K16R > npa3ΔC > NPA3 cells) but not to transcriptional elongation inhibitors 6-azauracil, mycophenolic acid or 1,10-phenanthroline. In all three mutant strains, the increase in sensitivity to both aminoglycoside antibiotics was totally rescued by expressing NPA3. Protein synthesis, visualized by quantifying puromycin incorporation into nascent-polypeptide chains, was markedly more sensitive to hygromycin B inhibition in npa3ΔC, npa3K16R, and npa3G70A than NPA3 cells. Notably, high-copy expression of the TIF11 gene, that encodes the eukaryotic translation initiation factor 1A (eIF1A) protein, completely suppressed both phenotypes (of reduced basal cell growth and increased sensitivity to hygromycin B) in npa3ΔC cells but not npa3K16R or npa3G70A cells. We conclude that Npa3 plays a critical RNAPII-independent and previously unrecognized role in translation initiation.
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Affiliation(s)
- Tania Félix-Pérez
- Instituto de Física, Universidad Autónoma de San Luis Potosí, Mexico
| | | | | | | | | | | | - Lina Riego-Ruiz
- División de Biología Molecular, IPICYT, San Luis Potosí, Mexico
| | | | - Mónica R Calera
- Instituto de Física, Universidad Autónoma de San Luis Potosí, Mexico
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2
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Peña-Gómez SG, Cristóbal-Mondragón GR, Vega-Palomo CR, Mora-García M, Félix-Pérez T, Rebolloso-Gómez Y, Calera MR, Sánchez-Olea R. Nucleocytoplasmic shuttling of the GPN-loop GTPase Gpn3 is regulated by serum and cell density in MCF-12A mammary cells. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119685. [PMID: 38342311 DOI: 10.1016/j.bbamcr.2024.119685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 01/07/2024] [Accepted: 02/01/2024] [Indexed: 02/13/2024]
Abstract
The best-known function of the essential GPN-loop GTPase Gpn3 is to contribute to RNA polymerase II assembly, a prerequisite for its nuclear targeting. Although this process occurs in the cytoplasm, we have previously shown that Gpn3 enters the cell nucleus before being polyubiquitinated. Here, we show that inhibiting Crm1-mediated nuclear export with leptomycin B, or the proteasome with MG132, caused the nuclear accumulation of recombinant and endogenous Gpn3 in MCF-12A cells. When added simultaneously, leptomycin B and MG132 had an additive effect. Analysis of Gpn3 primary sequence revealed the presence of at least five nuclear export sequence (NES) motifs, with some having a higher exposure to the solvent in the GTP-bound than GDP-bound state in a Gpn3 structural model. Inactivation of any of these NESes led to some degree of Gpn3 nuclear accumulation, although mutating NES1 or NES3 had the more robust effect. MCF-12A cells expressing exclusively a NES-deficient version of Gpn3R-Flag proliferated slower than cells expressing Gpn3R-Flag wt, indicating that nuclear export is important for Gpn3 function. Next, we searched for physiological conditions regulating Gpn3 nucleocytoplasmic shuttling. Interestingly, whereas Gpn3R-Flag was both nuclear and cytoplasmic in low-density growing MCF-12A cells, it was exclusively cytoplasmic in high-density areas. Furthermore, Gpn3R-Flag was cytoplasmic, mostly perinuclear, in sparse but starved MCF-12A cells, and serum-stimulation caused a rapid, although transient, Gpn3R-Flag nuclear accumulation. We conclude that Gpn3 nucleocytoplasmic shuttling is regulated by cell density and growth factors, and propose that Gpn3 has an unknown nuclear function positively linked to cell growth and/or proliferation.
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Affiliation(s)
- Sonia G Peña-Gómez
- Instituto de Física, Universidad Autónoma de San Luis Potosí, SLP, México
| | | | | | - Martín Mora-García
- Instituto de Física, Universidad Autónoma de San Luis Potosí, SLP, México
| | - Tania Félix-Pérez
- Instituto de Física, Universidad Autónoma de San Luis Potosí, SLP, México
| | | | - Mónica R Calera
- Instituto de Física, Universidad Autónoma de San Luis Potosí, SLP, México.
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3
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Korf L, Ye X, Vogt MS, Steinchen W, Watad M, van der Does C, Tourte M, Sivabalasarma S, Albers SV, Essen LO. Archaeal GPN-loop GTPases involve a lock-switch-rock mechanism for GTP hydrolysis. mBio 2023; 14:e0085923. [PMID: 37962382 PMCID: PMC10746158 DOI: 10.1128/mbio.00859-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 10/05/2023] [Indexed: 11/15/2023] Open
Abstract
IMPORTANCE GPN-loop GTPases have been found to be crucial for eukaryotic RNA polymerase II assembly and nuclear trafficking. Despite their ubiquitous occurrence in eukaryotes and archaea, the mechanism by which these GTPases mediate their function is unknown. Our study on an archaeal representative from Sulfolobus acidocaldarius showed that these dimeric GTPases undergo large-scale conformational changes upon GTP hydrolysis, which can be summarized as a lock-switch-rock mechanism. The observed requirement of SaGPN for motility appears to be due to its large footprint on the archaeal proteome.
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Affiliation(s)
- Lukas Korf
- Department of Chemistry, Philipps University, Marburg, Germany
| | - Xing Ye
- University of Freiburg, Institute of Biology, Molecular Biology of Archaea, Freiburg, Germany
| | - Marian S. Vogt
- Department of Chemistry, Philipps University, Marburg, Germany
| | - Wieland Steinchen
- Department of Chemistry, Philipps University, Marburg, Germany
- Center for Synthetic Microbiology (SYNMIKRO), Karl-von-Frisch-Strasse, Marburg, Germany
| | - Mohamed Watad
- Department of Chemistry, Philipps University, Marburg, Germany
| | - Chris van der Does
- University of Freiburg, Institute of Biology, Molecular Biology of Archaea, Freiburg, Germany
| | - Maxime Tourte
- University of Freiburg, Institute of Biology, Molecular Biology of Archaea, Freiburg, Germany
| | - Shamphavi Sivabalasarma
- University of Freiburg, Institute of Biology, Molecular Biology of Archaea, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
| | - Sonja-Verena Albers
- University of Freiburg, Institute of Biology, Molecular Biology of Archaea, Freiburg, Germany
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4
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Pinard M, Dastpeyman S, Poitras C, Bernard G, Gauthier MS, Coulombe B. Riluzole partially restores RNA polymerase III complex assembly in cells expressing the leukodystrophy-causative variant POLR3B R103H. Mol Brain 2022; 15:98. [PMID: 36451185 PMCID: PMC9710144 DOI: 10.1186/s13041-022-00974-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 10/16/2022] [Indexed: 12/12/2022] Open
Abstract
The mechanism of assembly of RNA polymerase III (Pol III), the 17-subunit enzyme that synthesizes tRNAs, 5 S rRNA, and other small-nuclear (sn) RNAs in eukaryotes, is not clearly understood. The recent discovery of the HSP90 co-chaperone PAQosome (Particle for Arrangement of Quaternary structure) revealed a function for this machinery in the biogenesis of nuclear RNA polymerases. However, the connection between Pol III subunits and the PAQosome during the assembly process remains unexplored. Here, we report the development of a mass spectrometry-based assay that allows the characterization of Pol III assembly. This assay was used to dissect the stages of Pol III assembly, to start defining the function of the PAQosome in this process, to dissect the assembly defects driven by the leukodystrophy-causative R103H substitution in POLR3B, and to discover that riluzole, an FDA-approved drug for alleviation of ALS symptoms, partly corrects these assembly defects. Together, these results shed new light on the mechanism and regulation of human nuclear Pol III biogenesis.
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Affiliation(s)
- Maxime Pinard
- grid.511547.30000 0001 2106 1695Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec Canada
| | - Samaneh Dastpeyman
- grid.511547.30000 0001 2106 1695Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec Canada
| | - Christian Poitras
- grid.511547.30000 0001 2106 1695Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec Canada
| | - Geneviève Bernard
- grid.63984.300000 0000 9064 4811Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, Canada ,grid.14709.3b0000 0004 1936 8649Department of Neurology and Neurosurgery, McGill University, Montreal, Canada ,grid.14709.3b0000 0004 1936 8649Department of Human Genetics, McGill University, Montreal, Canada ,grid.14709.3b0000 0004 1936 8649Department of Pediatrics, McGill University, Montreal, Canada ,grid.63984.300000 0000 9064 4811Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Canada
| | - Marie-Soleil Gauthier
- grid.511547.30000 0001 2106 1695Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec Canada
| | - Benoit Coulombe
- grid.511547.30000 0001 2106 1695Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec Canada ,grid.14848.310000 0001 2292 3357Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec Canada
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5
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Ma L, Wang L, Gao M, Zhang X, Zhao X, Xie D, Zhang J, Wang Z, Hou L, Zeng F. Rtr1 is required for Rpb1-Rpb2 assembly of RNAPII and prevents their cytoplasmic clump formation. FASEB J 2022; 36:e22585. [PMID: 36190433 DOI: 10.1096/fj.202200698rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 09/03/2022] [Accepted: 09/20/2022] [Indexed: 11/11/2022]
Abstract
RNA polymerase II (RNAPII) is an essential machinery for catalyzing mRNA synthesis and controlling cell fate in eukaryotes. Although the structure and function of RNAPII have been relatively defined, the molecular mechanism of its assembly process is not clear. The identification and functional analysis of assembly factors will provide new understanding to transcription regulation. In this study, we identify that RTR1, a known transcription regulator, is a new multicopy genetic suppressor of mutants of assembly factors Gpn3, Gpn2, and Rba50. We demonstrate that Rtr1 is directly required to assemble the two largest subunits of RNAPII by coordinating with Gpn3 and Npa3. Deletion of RTR1 leads to cytoplasmic clumping of RNAPII subunit and multiple copies of RTR1 can inhibit the formation of cytoplasmic clump of RNAPII subunit in gpn3-9 mutant, indicating a new layer function of Rtr1 in checking proper assembly of RNAPII. In addition, we find that disrupted activity of Rtr1 phosphatase does not trigger the formation of cytoplasmic clump of RNAPII subunit in a catalytically inactive mutant of RTR1. Based on these results, we conclude that Rtr1 cooperates with Gpn3 and Npa3 to assemble RNAPII core.
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Affiliation(s)
- Lujie Ma
- State Key Laboratory of North China Crop Improvement and Regulation, Baoding, China.,College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Le Wang
- College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Mengdi Gao
- College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Xinjie Zhang
- College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Xiangdong Zhao
- College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Debao Xie
- College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Jing Zhang
- College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Zhen Wang
- State Key Laboratory of North China Crop Improvement and Regulation, Baoding, China.,College of Science & Technology, Hebei Agricultural University, Cangzhou, China
| | - Lifeng Hou
- College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Fanli Zeng
- State Key Laboratory of North China Crop Improvement and Regulation, Baoding, China.,College of Life Sciences, Hebei Agricultural University, Baoding, China
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6
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Wolff DW, Bianchi-Smiraglia A, Nikiforov MA. Compartmentalization and regulation of GTP in control of cellular phenotypes. Trends Mol Med 2022; 28:758-769. [PMID: 35718686 PMCID: PMC9420775 DOI: 10.1016/j.molmed.2022.05.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 10/18/2022]
Abstract
Genetic or pharmacological inhibition of enzymes involved in GTP biosynthesis has substantial biological effects, underlining the need to better understand the function of GTP levels in regulation of cellular processes and the significance of targeting GTP biosynthesis enzymes for therapeutic intervention. Our current understanding of spatiotemporal regulation of GTP metabolism and its role in physiological and pathological cellular processes is far from complete. Novel methodologies such as genetically encoded sensors of free GTP offered insights into intracellular distribution and function of GTP molecules. In the current Review, we provide analysis of recent discoveries in the field of GTP metabolism and evaluate the key enzymes as molecular targets.
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Affiliation(s)
- David W Wolff
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC 27708, USA.
| | - Anna Bianchi-Smiraglia
- Department of Cell Stress Biology, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14203, USA
| | - Mikhail A Nikiforov
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC 27708, USA; Department of Pathology, Duke University School of Medicine, Durham, NC 27710, USA.
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7
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Development of a Methodology to Adapt an Equilibrium Buffer/Wash Applied to the Purification of hGPN2 Protein Expressed in Escherichia coli Using an IMAC Immobilized Metal Affinity Chromatography System. SEPARATIONS 2022. [DOI: 10.3390/separations9070164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022] Open
Abstract
Protein purification is a complex and non-standardized process; the fact that proteins have different structural types making it difficult to create a standard methodology to obtain them in a pure, soluble, and homogeneous form. The present study shows the selective development of a buffer suitable for proteins of interest that allows high concentrations of hGPN2 protein to be obtained with low polydispersion and high homogeneity and purity. By taking the different reagents used in the construction of different buffers as a basis and performing purifications using different additives in different concentrations to determine the optimal amounts, the developed process helps to minimize the bonds, maintain solubility, release the proteins present in inclusion bodies, and provide an adequate environment for obtaining high concentrations of pure protein. GPN proteins are of unknown function, have not been purified in high concentrations, and have been found as part of the RNA polymerase assembly; if they are not expressed, the cell dies, and overexpression of certain GPN proteins has been linked to decreased survival in patients with invasive ductal carcinoma breast cancer types ER+ and HER2+. The results of the present study show that the use of the buffer developed for recombinant hGPN2 protein expressed in Escherichia coli could be manipulated in order to isolate the protein in a totally pure form and without the use of protease inhibitor tablets. The resulting homogeneity and low polydispersion was corroborated by studies carried out using dynamic dispersion analysis. Thanks to these properties, it can be used for crystallography or structural genomics studies.
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8
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Synthetic negative genome screen of the GPN-loop GTPase NPA3 in Saccharomyces cerevisiae. Curr Genet 2022; 68:343-360. [PMID: 35660944 DOI: 10.1007/s00294-022-01243-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 04/21/2022] [Accepted: 04/30/2022] [Indexed: 11/03/2022]
Abstract
The GPN-loop GTPase Npa3 is encoded by an essential gene in the yeast Saccharomyces cerevisiae. Npa3 plays a critical role in the assembly and nuclear accumulation of RNA polymerase II (RNAPII), a function that may explain its essentiality. Genetic interactions describe the extent to which a mutation in a particular gene affects a specific phenotype when co-occurring with an alteration in a second gene. Discovering synthetic negative genetic interactions has long been used as a tool to delineate the functional relatedness between pairs of genes participating in common or compensatory biological pathways. Previously, our group showed that nuclear targeting and transcriptional activity of RNAPII were unaffected in cells expressing exclusively a C-terminal truncated mutant version of Npa3 (npa3∆C) lacking the last 106 residues naturally absent from the single GPN protein in Archaea, but universally conserved in all Npa3 orthologs of eukaryotes. To gain insight into novel cellular functions for Npa3, we performed here a genome-wide Synthetic Genetic Array (SGA) study coupled to bulk fluorescence monitoring to identify negative genetic interactions of NPA3 by crossing an npa3∆C strain with a 4,389 nonessential gene-deletion collection. This genetic screen revealed previously unknown synthetic negative interactions between NPA3 and 15 genes. Our results revealed that the Npa3 C-terminal tail extension regulates the participation of this essential GTPase in previously unknown biological processes related to mitochondrial homeostasis and ribosome biogenesis.
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9
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Npa3-Gpn3 cooperate to assemble RNA polymerase II and prevent clump of its subunits in the cytoplasm. Int J Biol Macromol 2022; 206:837-848. [PMID: 35314265 DOI: 10.1016/j.ijbiomac.2022.03.081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/11/2022] [Accepted: 03/13/2022] [Indexed: 01/16/2023]
Abstract
RNA polymerase II (RNAPII) is an essential machinery in eukaryotes that catalyzes mRNA synthesis and controls cell fate. Although the structure and function of RNAPII are relatively well defined, the molecular mechanism of its assembly process is poorly understood. Three members of GPN-loop GTPase family Npa3/Gpn1, Gpn2, and Gpn3 participate in the biogenesis of RNAPII with non-redundant roles. In this study, we demonstrate that Gpn3 and Npa3 directly participate in the assembly of the two largest subunits during biogenesis of RNAPII. When Gpn3 is defective, assembly of RNAPII is disrupted, leading to cytoplasmic foci of RNAPII subunits. Long-term assembly factor defects will lead to the accumulation of different kind of newly synthesized RNAPII subunits in the cytoplasm to form foci, and this can be prevented by recovery of the defective assembly factor. Cytoplasmic foci of RNAPII subunits in mutants of these assembly factors reveals a new cellular rescue response named the 'RNAPII assembly stress response'.
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10
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Leg length and bristle density, both necessary for water surface locomotion, are genetically correlated in water striders. Proc Natl Acad Sci U S A 2022; 119:2119210119. [PMID: 35193982 PMCID: PMC8892508 DOI: 10.1073/pnas.2119210119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2022] [Indexed: 11/18/2022] Open
Abstract
Access to hitherto unexploited ecological opportunities is associated with phenotypic evolution and often results in significant lineage diversification. Yet our understanding of the mechanisms underlying such adaptive traits remains limited. Water striders have been able to exploit the water-air interface, primarily facilitated by changes in the density of hydrophobic bristles and a significant increase in leg length. These two traits are functionally correlated and are both necessary for generating efficient locomotion on the water surface. Whether bristle density and leg length have any cellular or developmental genetic mechanisms in common is unknown. Here, we combine comparative genomics and transcriptomics with functional RNA interference assays to examine the developmental genetic and cellular mechanisms underlying the patterning of the bristles and the legs in Gerris buenoi and Mesovelia mulsanti, two species of water striders. We found that two duplication events in the genes beadex and taxi led to a functional expansion of the paralogs, which affected bristle density and leg length. We also identified genes for which no function in bristle development has been previously described in other insects. Interestingly, most of these genes play a dual role in regulating bristle development and leg length. In addition, these genes play a role in regulating cell division. This result suggests that cell division may be a common mechanism through which these genes can simultaneously regulate leg length and bristle density. We propose that pleiotropy, through which gene function affects the development of multiple traits, may play a prominent role in facilitating access to unexploited ecological opportunities and species diversification.
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11
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Wing CE, Fung HYJ, Chook YM. Karyopherin-mediated nucleocytoplasmic transport. Nat Rev Mol Cell Biol 2022; 23:307-328. [PMID: 35058649 PMCID: PMC10101760 DOI: 10.1038/s41580-021-00446-7] [Citation(s) in RCA: 117] [Impact Index Per Article: 58.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2021] [Indexed: 12/25/2022]
Abstract
Efficient and regulated nucleocytoplasmic trafficking of macromolecules to the correct subcellular compartment is critical for proper functions of the eukaryotic cell. The majority of the macromolecular traffic across the nuclear pores is mediated by the Karyopherin-β (or Kap) family of nuclear transport receptors. Work over more than two decades has shed considerable light on how the different Kap family members bring their respective cargoes into the nucleus or the cytoplasm in efficient and highly regulated manners. In this Review, we overview the main features and established functions of Kap family members, describe how Kaps recognize their cargoes and discuss the different ways in which these Kap-cargo interactions can be regulated, highlighting new findings and open questions. We also describe current knowledge of the import and export of the components of three large gene expression machines - the core replisome, RNA polymerase II and the ribosome - pointing out the questions that persist about how such large macromolecular complexes are trafficked to serve their function in a designated subcellular location.
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12
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Garrido-Godino AI, Gutiérrez-Santiago F, Navarro F. Biogenesis of RNA Polymerases in Yeast. Front Mol Biosci 2021; 8:669300. [PMID: 34026841 PMCID: PMC8136413 DOI: 10.3389/fmolb.2021.669300] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 03/31/2021] [Indexed: 01/25/2023] Open
Abstract
Eukaryotic RNA polymerases (RNA pols) transcriptional processes have been extensively investigated, and the structural analysis of eukaryotic RNA pols has been explored. However, the global assembly and biogenesis of these heteromultimeric complexes have been narrowly studied. Despite nuclear transcription being carried out by three RNA polymerases in eukaryotes (five in plants) with specificity in the synthesis of different RNA types, the biogenesis process has been proposed to be similar, at least for RNA pol II, to that of bacteria, which contains only one RNA pol. The formation of three different interacting subassembly complexes to conform the complete enzyme in the cytoplasm, prior to its nuclear import, has been assumed. In Saccharomyces cerevisiae, recent studies have examined in depth the biogenesis of RNA polymerases by characterizing some elements involved in the assembly of these multisubunit complexes, some of which are conserved in humans. This study reviews the latest studies governing the mechanisms and proteins described as being involved in the biogenesis of RNA polymerases in yeast.
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Affiliation(s)
- Ana I Garrido-Godino
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Jaén, Spain
| | | | - Francisco Navarro
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Jaén, Spain.,Centro de Estudios Avanzados en Aceite de Oliva y Olivar, Universidad de Jaén, Jaén, Spain
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13
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Chen L, Zhao M, Wu Z, Chen S, Rojo E, Luo J, Li P, Zhao L, Chen Y, Deng J, Cheng B, He K, Gou X, Li J, Hou S. RNA polymerase II associated proteins regulate stomatal development through direct interaction with stomatal transcription factors in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2021; 230:171-189. [PMID: 33058210 DOI: 10.1111/nph.17004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 10/05/2020] [Indexed: 05/27/2023]
Abstract
RNA polymerase II (Pol II) associated proteins (RPAPs) have been ascribed diverse functions at the cellular level; however, their roles in developmental processes in yeasts, animals and plants are very poorly understood. Through screening for interactors of NRPB3, which encodes the third largest subunit of Pol II, we identified RIMA, the orthologue of mammalian RPAP2. A combination of genetic and biochemical assays revealed the role of RIMA and other RPAPs in stomatal development in Arabidopsis thaliana. We show that RIMA is involved in nuclear import of NRPB3 and other Pol II subunits, and is essential for restraining division and for establishing cell identity in the stomatal cell lineage. Moreover, plant RPAPs IYO/RPAP1 and QQT1/RPAP4, which interact with RIMA, are also crucial for stomatal development. Importantly, RIMA and QQT1 bind physically to stomatal transcription factors SPEECHLESS, MUTE, FAMA and SCREAMs. The RIMA-QQT1-IYO complex could work together with key stomatal transcription factors and Pol II to drive cell fate transitions in the stomatal cell lineage. Direct interactions with stomatal transcription factors provide a novel mechanism by which RPAP proteins may control differentiation of cell types and tissues in eukaryotes.
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Affiliation(s)
- Liang Chen
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Mingfeng Zhao
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Zhongliang Wu
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Sicheng Chen
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Enrique Rojo
- Centro Nacional de Biotecnología-CSIC, Cantoblanco, Madrid, E-28049, Spain
| | - Jiangwei Luo
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Ping Li
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Lulu Zhao
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Yan Chen
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Jianming Deng
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Bo Cheng
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Kai He
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Xiaoping Gou
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Jia Li
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Suiwen Hou
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
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14
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Huang F, Huffman KE, Wang Z, Wang X, Li K, Cai F, Yang C, Cai L, Shih TS, Zacharias LG, Chung A, Yang Q, Chalishazar MD, Ireland AS, Stewart CA, Cargill K, Girard L, Liu Y, Ni M, Xu J, Wu X, Zhu H, Drapkin B, Byers LA, Oliver TG, Gazdar AF, Minna JD, DeBerardinis RJ. Guanosine triphosphate links MYC-dependent metabolic and ribosome programs in small-cell lung cancer. J Clin Invest 2021; 131:139929. [PMID: 33079728 PMCID: PMC7773395 DOI: 10.1172/jci139929] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 10/15/2020] [Indexed: 12/21/2022] Open
Abstract
MYC stimulates both metabolism and protein synthesis, but how cells coordinate these complementary programs is unknown. Previous work reported that, in a subset of small-cell lung cancer (SCLC) cell lines, MYC activates guanosine triphosphate (GTP) synthesis and results in sensitivity to inhibitors of the GTP synthesis enzyme inosine monophosphate dehydrogenase (IMPDH). Here, we demonstrated that primary MYChi human SCLC tumors also contained abundant guanosine nucleotides. We also found that elevated MYC in SCLCs with acquired chemoresistance rendered these otherwise recalcitrant tumors dependent on IMPDH. Unexpectedly, our data indicated that IMPDH linked the metabolic and protein synthesis outputs of oncogenic MYC. Coexpression analysis placed IMPDH within the MYC-driven ribosome program, and GTP depletion prevented RNA polymerase I (Pol I) from localizing to ribosomal DNA. Furthermore, the GTPases GPN1 and GPN3 were upregulated by MYC and directed Pol I to ribosomal DNA. Constitutively GTP-bound GPN1/3 mutants mitigated the effect of GTP depletion on Pol I, protecting chemoresistant SCLC cells from IMPDH inhibition. GTP therefore functioned as a metabolic gate tethering MYC-dependent ribosome biogenesis to nucleotide sufficiency through GPN1 and GPN3. IMPDH dependence is a targetable vulnerability in chemoresistant MYChi SCLC.
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Affiliation(s)
- Fang Huang
- Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Children’s Medical Center Research Institute
| | - Kenneth E. Huffman
- Hamon Center for Therapeutic Oncology Research, Departments of Internal Medicine and Pharmacology, and Simmons Comprehensive Cancer Center
| | - Zixi Wang
- Children’s Medical Center Research Institute
| | - Xun Wang
- Children’s Medical Center Research Institute
| | - Kailong Li
- Children’s Medical Center Research Institute
| | - Feng Cai
- Children’s Medical Center Research Institute
| | | | - Ling Cai
- Children’s Medical Center Research Institute
- Department of Population and Data Sciences, and
| | | | | | | | - Qian Yang
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Milind D. Chalishazar
- Department of Oncological Sciences, University of Utah, Huntsman Cancer Institute, Salt Lake City, Utah, USA
| | - Abbie S. Ireland
- Department of Oncological Sciences, University of Utah, Huntsman Cancer Institute, Salt Lake City, Utah, USA
| | - C. Allison Stewart
- Department of Thoracic/Head and Neck Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Kasey Cargill
- Department of Thoracic/Head and Neck Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Luc Girard
- Hamon Center for Therapeutic Oncology Research, Departments of Internal Medicine and Pharmacology, and Simmons Comprehensive Cancer Center
| | - Yi Liu
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Min Ni
- Children’s Medical Center Research Institute
| | - Jian Xu
- Children’s Medical Center Research Institute
| | - Xudong Wu
- Department of Cell Biology, Tianjin Medical University, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Key Laboratory of Medical Epigenetics, Tianjin, China
| | - Hao Zhu
- Children’s Medical Center Research Institute
| | - Benjamin Drapkin
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Lauren A. Byers
- Department of Thoracic/Head and Neck Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Trudy G. Oliver
- Department of Oncological Sciences, University of Utah, Huntsman Cancer Institute, Salt Lake City, Utah, USA
| | - Adi F. Gazdar
- Hamon Center for Therapeutic Oncology Research, Departments of Internal Medicine and Pharmacology, and Simmons Comprehensive Cancer Center
| | - John D. Minna
- Hamon Center for Therapeutic Oncology Research, Departments of Internal Medicine and Pharmacology, and Simmons Comprehensive Cancer Center
| | - Ralph J. DeBerardinis
- Children’s Medical Center Research Institute
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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15
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Bandini G, Agop-Nersesian C, van der Wel H, Mandalasi M, Kim HW, West CM, Samuelson J. The nucleocytosolic O-fucosyltransferase SPINDLY affects protein expression and virulence in Toxoplasma gondii. J Biol Chem 2021; 296:100039. [PMID: 33158988 PMCID: PMC7949088 DOI: 10.1074/jbc.ra120.015883] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 10/23/2020] [Accepted: 11/06/2020] [Indexed: 12/12/2022] Open
Abstract
Once considered unusual, nucleocytoplasmic glycosylation is now recognized as a conserved feature of eukaryotes. While in animals, O-GlcNAc transferase (OGT) modifies thousands of intracellular proteins, the human pathogen Toxoplasma gondii transfers a different sugar, fucose, to proteins involved in transcription, mRNA processing, and signaling. Knockout experiments showed that TgSPY, an ortholog of plant SPINDLY and paralog of host OGT, is required for nuclear O-fucosylation. Here we verify that TgSPY is the nucleocytoplasmic O-fucosyltransferase (OFT) by 1) complementation with TgSPY-MYC3, 2) its functional dependence on amino acids critical for OGT activity, and 3) its ability to O-fucosylate itself and a model substrate and to specifically hydrolyze GDP-Fuc. While many of the endogenous proteins modified by O-Fuc are important for tachyzoite fitness, O-fucosylation by TgSPY is not essential. Growth of Δspy tachyzoites in fibroblasts is modestly affected, despite marked reductions in the levels of ectopically expressed proteins normally modified with O-fucose. Intact TgSPY-MYC3 localizes to the nucleus and cytoplasm, whereas catalytic mutants often displayed reduced abundance. Δspy tachyzoites of a luciferase-expressing type II strain exhibited infection kinetics in mice similar to wild-type but increased persistence in the chronic brain phase, potentially due to an imbalance of regulatory protein levels. The modest changes in parasite fitness in vitro and in mice, despite profound effects on reporter protein accumulation, and the characteristic punctate localization of O-fucosylated proteins suggest that TgSPY controls the levels of proteins to be held in reserve for response to novel stresses.
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Affiliation(s)
- Giulia Bandini
- Department of Molecular and Cell Biology, Boston University Henry Goldman School of Dental Medicine, Boston, Massachusetts, USA.
| | - Carolina Agop-Nersesian
- Department of Molecular and Cell Biology, Boston University Henry Goldman School of Dental Medicine, Boston, Massachusetts, USA
| | - Hanke van der Wel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Msano Mandalasi
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Hyun W Kim
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Christopher M West
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - John Samuelson
- Department of Molecular and Cell Biology, Boston University Henry Goldman School of Dental Medicine, Boston, Massachusetts, USA
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16
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Liu X, Xie D, Hua Y, Zeng P, Ma L, Zeng F. Npa3 interacts with Gpn3 and assembly factor Rba50 for RNA polymerase II biogenesis. FASEB J 2020; 34:15547-15558. [PMID: 32985767 DOI: 10.1096/fj.202001523r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 09/01/2020] [Accepted: 09/15/2020] [Indexed: 12/12/2022]
Abstract
RNA polymerase II is one of the most vital macromolecular complexes in eukaryotes and the assembly of such complete enzyme requires many factors. Three members of GPN-loop GTPase family Npa3/Gpn1, Gpn2, and Gpn3 participate in the biogenesis of RNA polymerase II with nonredundant roles. We show here that rapid degradation of each GPN protein in yeast leads to cytoplasmic accumulation of Rpb1 and defects in the assembly of RNA polymerase II, suggesting conserved functions of GPN paralogs for RNA polymerase II biogenesis as in humans. Taking advantage of a multicopy genetic screening, we identified GPN3 and assembly factor RBA50 among others as strong suppressors of npa3ts mutants. We further demonstrated that Npa3 interacts with Gpn3 and Rba50, similarly human Gpn1 physically interacts with Gpn3 and RPAP1 (human analog of Rba50). Moreover, a mutual dependency of protein levels of Npa3 and Gpn3 was also clearly presented in yeast using an auxin-inducible degron (AID) system. Interestingly, Rpb2, the second largest subunit of RNA polymerase II was determined to be the subunit that interacts with both Gpn1 and Rba50, indicating a close association of Npa3 and Rba50 in Rpb2 subcomplex assembly. Based on these results, we conclude that Npa3 interacts with Gpn3 and Rba50, for RNA polymerase II biogenesis. We therefore propose that multiple factors may coordinate through conserved regulatory mechanisms in the assembly of RNA polymerase complex.
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Affiliation(s)
- Xueqin Liu
- College of Life Sciences, Hebei Agricultural University, Baoding, China.,State Key Laboratory of North China Crop Improvement and Regulation, Baoding, China
| | - Debao Xie
- College of Life Sciences, Hebei Agricultural University, Baoding, China.,State Key Laboratory of North China Crop Improvement and Regulation, Baoding, China
| | - Yu Hua
- Peking-Tsinghua Center for Life Sciences, The National Laboratory of Protein and Plant Gene Research, The College of Life Sciences, Peking University, Beijing, China
| | - Pei Zeng
- College of Life Sciences, Hebei Agricultural University, Baoding, China.,State Key Laboratory of North China Crop Improvement and Regulation, Baoding, China
| | - Lujie Ma
- College of Life Sciences, Hebei Agricultural University, Baoding, China.,State Key Laboratory of North China Crop Improvement and Regulation, Baoding, China
| | - Fanli Zeng
- College of Life Sciences, Hebei Agricultural University, Baoding, China.,State Key Laboratory of North China Crop Improvement and Regulation, Baoding, China.,Peking-Tsinghua Center for Life Sciences, The National Laboratory of Protein and Plant Gene Research, The College of Life Sciences, Peking University, Beijing, China
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17
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Ye X, Vogt MS, van der Does C, Bildl W, Schulte U, Essen LO, Albers SV. The Phosphatase PP2A Interacts With ArnA and ArnB to Regulate the Oligomeric State and the Stability of the ArnA/B Complex. Front Microbiol 2020; 11:1849. [PMID: 32973695 PMCID: PMC7472852 DOI: 10.3389/fmicb.2020.01849] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/15/2020] [Indexed: 12/30/2022] Open
Abstract
In the crenarchaeon Sulfolobus acidocaldarius, the archaellum, a type-IV pilus like motility structure, is synthesized in response to nutrient starvation. Synthesis of components of the archaellum is controlled by the archaellum regulatory network (arn). Protein phosphorylation plays an important role in this regulatory network since the deletion of several genes encoding protein kinases and the phosphatase PP2A affected cell motility. Several proteins in the archaellum regulatory network can be phosphorylated, however, details of how phosphorylation levels of different components affect archaellum synthesis are still unknown. To identify proteins interacting with the S. acidocaldarius phosphatases PTP and PP2A, co-immunoprecipitation assays coupled to mass spectrometry analysis were performed. Thirty minutes after growth in nutrient starvation medium, especially a conserved putative ATP/GTP binding protein (Saci_1281), a universal stress protein (Saci_0887) and the archaellum regulators ArnA and ArnB were identified as highly abundant interaction proteins of PP2A. The interaction between ArnA, ArnB, and PP2A was further studied. Previous studies showed that the Forkhead-associated domain containing ArnA interacts with von Willebrand type A domain containing ArnB, and that both proteins could be phosphorylated by the kinase ArnC in vitro. The ArnA/B heterodimer was reconstituted from the purified proteins. In complex with ArnA, phosphorylation of ArnB by the ArnC kinase was strongly stimulated and resulted in formation of (ArnA/B)2 and higher oligomeric complexes, while association and dephosphorylation by PP2A resulted in dissociation of these ArnA/B complexes.
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Affiliation(s)
- Xing Ye
- Molecular Biology of Archaea, Institute of Biology II, University of Freiburg, Freiburg, Germany
| | | | - Chris van der Does
- Molecular Biology of Archaea, Institute of Biology II, University of Freiburg, Freiburg, Germany
| | - Wolfgang Bildl
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Uwe Schulte
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Center for Biological Signaling Studies(BIOSS), Freiburg, Germany.,Center for Integrative Signaling Studies (CIBSS), Freiburg, Germany
| | - Lars-Oliver Essen
- Department of Chemistry, Philipps University Marburg, Marburg, Germany.,Loewe Center for Synthetic Microbiology, Marburg, Germany
| | - Sonja-Verena Albers
- Molecular Biology of Archaea, Institute of Biology II, University of Freiburg, Freiburg, Germany.,Center for Biological Signaling Studies(BIOSS), Freiburg, Germany
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18
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Lara-Chacón B, Guerrero-Rodríguez SL, Ramírez-Hernández KJ, Robledo-Rivera AY, Velazquez MAV, Sánchez-Olea R, Calera MR. Gpn3 Is Essential for Cell Proliferation of Breast Cancer Cells Independent of Their Malignancy Degree. Technol Cancer Res Treat 2020; 18:1533033819870823. [PMID: 31431135 PMCID: PMC6704425 DOI: 10.1177/1533033819870823] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Successful therapies for patients with breast cancer often lose their initial effectiveness. Thus, identifying new molecular targets is a constant goal in the fight against breast cancer. Gpn3 is a protein required for RNA polymerase II nuclear targeting in both yeast and human cells. We investigated here the effect of suppressing Gpn3 expression on cell proliferation in a progression series of isogenic cell lines derived from the nontumorigenic MCF-10A breast cells that recapitulate different stages of breast carcinogenesis. Gpn3 protein levels were comparable in all malignant derivatives of the nontumorigenic MCF-10A cells. shRNA-mediated inhibition of Gpn3 expression markedly decreased cell proliferation in all MCF-10A sublines. A fraction of the largest RNA polymerase II subunit Rpb1 was retained in the cytoplasm, but most Rpb1 remained nuclear after suppressing Gpn3 in all cell lines studied. Long-term proliferation experiments in cells with suppressed Gpn3 expression resulted in the eventual loss of all isogenic cell lines but MCF-10CA1d.cl1. In MCF-10CA1d.cl1 cells, Gpn3 knockdown reduced the proliferation of breast cancer stem cells as evaluated by mammosphere assays. After the identification that Gpn3 plays a key role in cell proliferation in mammary epithelial cells independent of the degree of transformation, we also analyzed the importance of Gpn3 in other human breast cancer cell lines from different subtypes. Gpn3 was also required for cell proliferation and nuclear translocation of RNA polymerase II in such cellular models. Altogether, our results show that Gpn3 is essential for breast cancer cell proliferation regardless of the transformation level, indicating that Gpn3 could be considered a molecular target for the development of new antiproliferative therapies. Importantly, our analysis of public data revealed that Gpn3 overexpression was associated with a significant decrease in overall survival in patients with estrogen receptor-positive and Human epidermal growth factor receptor 2 (HER2+) breast cancer, supporting our proposal that targeting Gpn3 could potentially benefit patients with breast cancer.
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Affiliation(s)
- Bárbara Lara-Chacón
- 1 Instituto de Fisica Manuel Sandoval Vallarta, Universidad Autonoma de San Luis Potos, San Luis Potosi, Mexico
| | | | - Karla J Ramírez-Hernández
- 1 Instituto de Fisica Manuel Sandoval Vallarta, Universidad Autonoma de San Luis Potos, San Luis Potosi, Mexico
| | | | - Marco Antonio Velasco Velazquez
- 2 Departamento de Farmacología y Unidad Periférica de Investigación en Biomedicina Traslacional, México city, México.,3 Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Roberto Sánchez-Olea
- 1 Instituto de Fisica Manuel Sandoval Vallarta, Universidad Autonoma de San Luis Potos, San Luis Potosi, Mexico
| | - Mónica Raquel Calera
- 1 Instituto de Fisica Manuel Sandoval Vallarta, Universidad Autonoma de San Luis Potos, San Luis Potosi, Mexico
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19
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Contreras R, Kallemi P, González-García MP, Lazarova A, Sánchez-Serrano JJ, Sanmartín M, Rojo E. Identification of Domains and Factors Involved in MINIYO Nuclear Import. FRONTIERS IN PLANT SCIENCE 2019; 10:1044. [PMID: 31552063 PMCID: PMC6748027 DOI: 10.3389/fpls.2019.01044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 07/29/2019] [Indexed: 05/28/2023]
Abstract
The transition of stem cells from self-renewal into differentiation is tightly regulated to assure proper development of the organism. Arabidopsis MINIYO (IYO) and its mammalian orthologue RNA polymerase II associated protein 1 (RPAP1) are essential factors for initiating stem cell differentiation in plants and animals. Moreover, there is evidence suggesting that the translocation of IYO and RPAP1 from the cytosol into the nucleus functions as a molecular switch to initiate this cell fate transition. Identifying the determinants of IYO subcellular localization would allow testing if, indeed, nuclear IYO migration triggers cell differentiation and could provide tools to control this crucial developmental transition. Through transient and stable expression assays in Nicotiana benthamiana and Arabidopsis thaliana, we demonstrate that IYO contains two nuclear localization signals (NLSs), located at the N- and C-terminus of the protein, which mediate the interaction with the NLS-receptor IMPA4 and the import of the protein into the nucleus. Interestingly, IYO also interacts with GPN GTPases, which are involved in selective nuclear import of RNA polymerase II. This interaction is prevented when the G1 motif in GPN1 is mutated, suggesting that IYO binds specifically to the nucleotide-bound form of GPN1. In contrast, deleting the NLSs in IYO does not prevent the interaction with GPN1, but it interferes with import of GPN1 into the nucleus, indicating that IYO and GPN1 are co-transported as a complex that requires the IYO NLSs for import. This work unveils key domains and factors involved in IYO nuclear import, which may prove instrumental to determine how IYO and RPAP1 control stem cell differentiation.
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Affiliation(s)
| | | | | | | | | | | | - Enrique Rojo
- *Correspondence: Maite Sanmartín, , ; Enrique Rojo,
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20
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Cristóbal-Mondragón GR, Lara-Chacón B, Santiago Á, De-la-Rosa V, González-González R, Muñiz-Luna JA, Ladrón-de-Guevara E, Romero-Romero S, Rangel-Yescas GE, Fernández Velasco DA, Islas LD, Pastor N, Sánchez-Olea R, Calera MR. FRET-based analysis and molecular modeling of the human GPN-loop GTPases 1 and 3 heterodimer unveils a dominant-negative protein complex. FEBS J 2019; 286:4797-4818. [PMID: 31298811 DOI: 10.1111/febs.14996] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 05/08/2019] [Accepted: 07/09/2019] [Indexed: 01/09/2023]
Abstract
GPN-loop GTPases 1 and 3 are required for RNA polymerase II (RNAPII) nuclear import. Gpn1 and Gpn3 display some sequence similarity, physically associate, and their protein expression levels are mutually dependent in human cells. We performed here Fluorescence Resonance Energy Transfer (FRET), molecular modeling, and cell biology experiments to understand, and eventually disrupt, human Gpn1-Gpn3 interaction in live HEK293-AD cells. Transiently expressed EYFP-Gpn1 and Gpn3-CFP generated a strong FRET signal, indicative of a very close proximity, in the cytoplasm of HEK293-AD cells. Molecular modeling of the human Gpn1-Gpn3 heterodimer based on the crystallographic structure of Npa3, the Saccharomyces cerevisiae Gpn1 ortholog, revealed that human Gpn1 and Gpn3 associate through a large interaction surface formed by internal α-helix 7, insertion 2, and the GPN-loop from each protein. In site-directed mutagenesis experiments of interface residues, we identified the W132D and M227D EYFP-Gpn1 mutants as defective to produce a FRET signal when coexpressed with Gpn3-CFP. Simultaneous but not individual expression of Gpn1 and Gpn3, with either or both proteins fused to EYFP, retained RNAPII in the cytoplasm and markedly inhibited global transcription in HEK293-AD cells. Interestingly, the W132D and M227D Gpn1 mutants that showed an impaired ability to interact with Gpn3 by FRET were also unable to delocalize RNAPII in this assay, indicating that an intact Gpn1-Gpn3 interaction is required to display the dominant-negative effect on endogenous Gpn1/Gpn3 function we described here. Altogether, our results suggest that a Gpn1-Gpn3 strong interaction is critical for their cellular function.
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Affiliation(s)
| | - Bárbara Lara-Chacón
- Instituto de Física, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP, México
| | - Ángel Santiago
- Centro de Investigación en Dinámica Celular-IICBA, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mor, México
| | - Víctor De-la-Rosa
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Coyoacán, CDMX, México
| | | | - Julio A Muñiz-Luna
- Instituto de Física, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP, México
| | - Ernesto Ladrón-de-Guevara
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Coyoacán, CDMX, México
| | - Sergio Romero-Romero
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Facultad de Medicina, Universidad Nacional Autónoma de México, Coyoacán, CDMX, México
| | - Gisela E Rangel-Yescas
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Coyoacán, CDMX, México
| | - Daniel Alejandro Fernández Velasco
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Facultad de Medicina, Universidad Nacional Autónoma de México, Coyoacán, CDMX, México
| | - León D Islas
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Coyoacán, CDMX, México
| | - Nina Pastor
- Centro de Investigación en Dinámica Celular-IICBA, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mor, México
| | - Roberto Sánchez-Olea
- Instituto de Física, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP, México
| | - Mónica R Calera
- Instituto de Física, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP, México
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21
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Burriss KH, Mosley AL. Methods review: Mass spectrometry analysis of RNAPII complexes. Methods 2019; 159-160:105-114. [PMID: 30902665 DOI: 10.1016/j.ymeth.2019.03.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/04/2019] [Accepted: 03/17/2019] [Indexed: 12/20/2022] Open
Abstract
RNA Polymerase II (RNAPII) is responsible for transcribing multiple RNA species throughout eukaryotes. A variety of protein-protein interactions occur throughout the transcription cycle for coordinated regulation of transcription initiation, elongation, and/or termination. Taking a proteomics approach to study RNAPII transcription thereby offers a comprehensive view of both RNAPII biology and the variety of proteins that regulate the process itself. This review will focus on how mass spectrometry (MS) methods have expanded understanding of RNAPII and its transcription-regulatory interaction partners. The application of affinity purification mass spectrometry has led to the discovery of a number of novel groups of proteins that regulate an array of RNAPII biology ranging from nuclear import to regulation of phosphorylation state. Additionally, a number of methods have been developed using mass spectrometry to measure protein subunit stoichiometry within and across protein complexes and to perform various types of architectural analysis using structural proteomics approaches. The key methods that we will focus on related to RNAPII mass spectrometry analyses include: affinity purification mass spectrometry, protein post-translational modification analysis, crosslinking mass spectrometry, and native mass spectrometry.
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Affiliation(s)
- Katlyn Hughes Burriss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46402, United States
| | - Amber L Mosley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46402, United States; Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46402, United States.
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22
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Basu S, Finke A, Vera L, Wang M, Olieric V. Making routine native SAD a reality: lessons from beamline X06DA at the Swiss Light Source. Acta Crystallogr D Struct Biol 2019; 75:262-271. [PMID: 30950397 PMCID: PMC6450063 DOI: 10.1107/s2059798319003103] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 03/01/2019] [Indexed: 01/19/2023] Open
Abstract
Native single-wavelength anomalous dispersion (SAD) is the most attractive de novo phasing method in macromolecular crystallography, as it directly utilizes intrinsic anomalous scattering from native crystals. However, the success of such an experiment depends on accurate measurements of the reflection intensities and therefore on careful data-collection protocols. Here, the low-dose, multiple-orientation data-collection protocol for native SAD phasing developed at beamline X06DA (PXIII) at the Swiss Light Source is reviewed, and its usage over the last four years on conventional crystals (>50 µm) is reported. Being experimentally very simple and fast, this method has gained popularity and has delivered 45 de novo structures to date (13 of which have been published). Native SAD is currently the primary choice for experimental phasing among X06DA users. The method can address challenging cases: here, native SAD phasing performed on a streptavidin-biotin crystal with P21 symmetry and a low Bijvoet ratio of 0.6% is highlighted. The use of intrinsic anomalous signals as sequence markers for model building and the assignment of ions is also briefly described.
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Affiliation(s)
- Shibom Basu
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - Aaron Finke
- MacCHESS, Cornell University, Ithaca, New York, USA
| | - Laura Vera
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - Meitian Wang
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - Vincent Olieric
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
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Gpn2 and Rba50 Directly Participate in the Assembly of the Rpb3 Subcomplex in the Biogenesis of RNA Polymerase II. Mol Cell Biol 2018; 38:MCB.00091-18. [PMID: 29661922 DOI: 10.1128/mcb.00091-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 04/08/2018] [Indexed: 01/12/2023] Open
Abstract
RNA polymerase II (RNAPII) is one of the central enzymes in cell growth and organizational development. It is a large macromolecular complex consisting of 12 subunits. Relative to the clear definition of RNAPII structure and biological function, the molecular mechanism of how RNAPII is assembled is poorly understood, and thus the key assembly factors acting for the assembly of RNAPII remain elusive. In this study, we identified two factors, Gpn2 and Rba50, that directly participate in the assembly of RNAPII. Gpn2 and Rba50 were demonstrated to interact with Rpb12 and Rpb3, respectively. An interaction between Gpn2 and Rba50 was also demonstrated. When Gpn2 and Rba50 are functionally defective, the assembly of the Rpb3 subcomplex is disrupted, leading to defects in the assembly of RNAPII. Based on these results, we conclude that Gpn2 and Rba50 directly participate in the assembly of the Rpb3 subcomplex and subsequently the biogenesis of RNAPII.
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Li Y, Yuan Y, Fang X, Lu X, Lian B, Zhao G, Qi Y. A Role for MINIYO and QUATRE-QUART2 in the Assembly of RNA Polymerases II, IV, and V in Arabidopsis. THE PLANT CELL 2018; 30:466-480. [PMID: 29352065 PMCID: PMC5868690 DOI: 10.1105/tpc.17.00380] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 01/09/2018] [Accepted: 01/17/2018] [Indexed: 05/15/2023]
Abstract
RNA polymerases IV and V (Pol IV and Pol V) are required for the generation of noncoding RNAs in RNA-directed DNA methylation (RdDM). Their subunit compositions resemble that of Pol II. The mechanism and accessory factors involved in their assembly remain largely unknown. In this study, we identified mutant alleles of MINIYO (IYO), QUATRE-QUART2 (QQT2), and NUCLEAR RNA POLYMERASE B11/D11/E11 (NRPB/D/E11) that cause defects in RdDM in Arabidopsis thaliana We found that Pol IV-dependent small interfering RNAs and Pol V-dependent transcripts were greatly reduced in the mutants. NRPE1, the largest subunit of Pol V, failed to associate with other Pol V subunits in the iyo and qqt2 mutants, suggesting the involvement of IYO and QQT2 in Pol V assembly. In addition, we found that IYO and QQT2 were mutually dependent for their association with the NRPE3 subassembly prior to the assembly of Pol V holoenzyme. Finally, we show that IYO and QQT2 are similarly required for the assembly of Pol II and Pol IV. Our findings reveal IYO and QQT2 as cofactors for the assembly of Pol II, Pol IV, and Pol V and provide mechanistic insights into how RNA polymerases are assembled in plants.
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Affiliation(s)
- Yaoxi Li
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Graduate Program, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
- National Institute of Biological Sciences, Beijing 102206, China
| | - Yuxiang Yuan
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, Tsinghua University, Beijing 100084, China
| | - Xiaofeng Fang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiuli Lu
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Bi Lian
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Gaozhan Zhao
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Yijun Qi
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Graduate Program, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
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Muñoz A, Mangano S, González-García MP, Contreras R, Sauer M, De Rybel B, Weijers D, Sánchez-Serrano JJ, Sanmartín M, Rojo E. RIMA-Dependent Nuclear Accumulation of IYO Triggers Auxin-Irreversible Cell Differentiation in Arabidopsis. THE PLANT CELL 2017; 29:575-588. [PMID: 28223441 PMCID: PMC5385956 DOI: 10.1105/tpc.16.00791] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 12/28/2016] [Accepted: 02/14/2017] [Indexed: 05/09/2023]
Abstract
The transcriptional regulator MINIYO (IYO) is essential and rate-limiting for initiating cell differentiation in Arabidopsis thaliana Moreover, IYO moves from the cytosol into the nucleus in cells at the meristem periphery, possibly triggering their differentiation. However, the genetic mechanisms controlling IYO nuclear accumulation were unknown, and the evidence that increased nuclear IYO levels trigger differentiation remained correlative. Searching for IYO interactors, we identified RPAP2 IYO Mate (RIMA), a homolog of yeast and human proteins linked to nuclear import of selective cargo. Knockdown of RIMA causes delayed onset of cell differentiation, phenocopying the effects of IYO knockdown at the transcriptomic and developmental levels. Moreover, differentiation is completely blocked when IYO and RIMA activities are simultaneously reduced and is synergistically accelerated when IYO and RIMA are concurrently overexpressed, confirming their functional interaction. Indeed, RIMA knockdown reduces the nuclear levels of IYO and prevents its prodifferentiation activity, supporting the conclusion that RIMA-dependent nuclear IYO accumulation triggers cell differentiation in Arabidopsis. Importantly, by analyzing the effect of the IYO/RIMA pathway on xylem pole pericycle cells, we provide compelling evidence reinforcing the view that the capacity for de novo organogenesis and regeneration from mature plant tissues can reside in stem cell reservoirs.
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Affiliation(s)
- Alfonso Muñoz
- Centro Nacional de Biotecnología-CSIC, Cantoblanco, E-28049 Madrid, Spain
| | - Silvina Mangano
- Centro Nacional de Biotecnología-CSIC, Cantoblanco, E-28049 Madrid, Spain
| | | | - Ramón Contreras
- Centro Nacional de Biotecnología-CSIC, Cantoblanco, E-28049 Madrid, Spain
| | - Michael Sauer
- Centro Nacional de Biotecnología-CSIC, Cantoblanco, E-28049 Madrid, Spain
| | - Bert De Rybel
- Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, The Netherlands
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, The Netherlands
| | | | - Maite Sanmartín
- Centro Nacional de Biotecnología-CSIC, Cantoblanco, E-28049 Madrid, Spain
| | - Enrique Rojo
- Centro Nacional de Biotecnología-CSIC, Cantoblanco, E-28049 Madrid, Spain
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26
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Human Gpn1 purified from bacteria binds guanine nucleotides and hydrolyzes GTP as a protein dimer stabilized by its C-terminal tail. Protein Expr Purif 2017; 132:85-96. [PMID: 28153773 DOI: 10.1016/j.pep.2017.01.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 12/23/2016] [Accepted: 01/25/2017] [Indexed: 12/20/2022]
Abstract
The essential GTPase Gpn1 mediates RNA polymerase II nuclear targeting and controls microtubule dynamics in yeast and human cells by molecular mechanisms still under investigation. Here, we purified human HisGpn1 expressed as a recombinant protein in bacteria E. coli BL-21 (DE3). Affinity purified HisGpn1 eluted from a size exclusion column as a protein dimer, a state conserved after removing the hexa-histidine tail and confirmed by separating HisGpn1 in native gels, and in dynamic light scattering experiments. Human HisGpn1 purity was higher than 95%, molecularly monodisperse and could be concentrated to more than 10 mg/mL without aggregating. Circular dichroism spectra showed that human HisGpn1 was properly folded and displayed a secondary structure rich in alpha helices. HisGpn1 effectively bound GDP and the non-hydrolyzable GTP analogue GMPPCP, and hydrolyzed GTP. We next tested the importance of the C-terminal tail, present in eukaryotic Gpn1 but not in the ancestral archaeal Gpn protein, on HisGpn1 dimer formation. C-terminal deleted human HisGpn1 (HisGpn1ΔC) was also purified as a protein dimer, indicating that the N-terminal GTPase domain contains the interaction surface needed for dimer formation. In contrast to HisGpn1, however, HisGpn1ΔC dimer spontaneously dissociated into monomers. In conclusion, we have developed a method to purify properly folded and functionally active human HisGpn1 from bacteria, and showed that the C-terminal tail, universally conserved in all eukaryotic Gpn1 orthologues, stabilizes the GTPase domain-mediated Gpn1 protein dimer. The availability of recombinant human Gpn1 will open new research avenues to unveil the molecular and pharmacological properties of this essential GTPase.
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27
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Guerrero-Serrano G, Castanedo L, Cristóbal-Mondragón GR, Montalvo-Arredondo J, Riego-Ruíz L, DeLuna A, De Las Peñas A, Castaño I, Calera MR, Sánchez-Olea R. Npa3/ScGpn1 carboxy-terminal tail is dispensable for cell viability and RNA polymerase II nuclear targeting but critical for microtubule stability and function. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:451-462. [PMID: 27965115 DOI: 10.1016/j.bbamcr.2016.12.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 12/03/2016] [Accepted: 12/09/2016] [Indexed: 10/20/2022]
Abstract
Genetic deletion of the essential GTPase Gpn1 or replacement of the endogenous gene by partial loss of function mutants in yeast is associated with multiple cellular phenotypes, including in all cases a marked cytoplasmic retention of RNA polymerase II (RNAPII). Global inhibition of RNAPII-mediated transcription due to malfunction of Gpn1 precludes the identification and study of other cellular function(s) for this GTPase. In contrast to the single Gpn protein present in Archaea, eukaryotic Gpn1 possesses an extension of approximately 100 amino acids at the C-terminal end of the GTPase domain. To determine the importance of this C-terminal extension in Saccharomyces cerevisiae Gpn1, we generated yeast strains expressing either C-terminal truncated (gpn1ΔC) or full-length ScGpn1. We found that ScGpn1ΔC was retained in the cell nucleus, an event physiologically relevant as gpn1ΔC cells contained a higher nuclear fraction of the RNAPII CTD phosphatase Rtr1. gpn1ΔC cells displayed an increased size, a delay in mitosis exit, and an increased sensitivity to the microtubule polymerization inhibitor benomyl at the cell proliferation level and two cellular events that depend on microtubule function: RNAPII nuclear targeting and vacuole integrity. These phenotypes were not caused by inhibition of RNAPII, as in gpn1ΔC cells RNAPII nuclear targeting and transcriptional activity were unaffected. These data, combined with our description here of a genetic interaction between GPN1 and BIK1, a microtubule plus-end tracking protein with a mitotic function, strongly suggest that the ScGpn1 C-terminal tail plays a critical role in microtubule dynamics and mitotic progression in an RNAPII-independent manner.
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Affiliation(s)
- Gehenna Guerrero-Serrano
- Instituto de Física, Universidad Autónoma de San Luis Potosí, Manuel Nava 6, Zona Univesitaria, C.P. 78290, San Luis Potosí, San Luis Potosí, Mexico
| | - Leonardo Castanedo
- Instituto de Física, Universidad Autónoma de San Luis Potosí, Manuel Nava 6, Zona Univesitaria, C.P. 78290, San Luis Potosí, San Luis Potosí, Mexico
| | - Gema R Cristóbal-Mondragón
- Instituto de Física, Universidad Autónoma de San Luis Potosí, Manuel Nava 6, Zona Univesitaria, C.P. 78290, San Luis Potosí, San Luis Potosí, Mexico
| | - Javier Montalvo-Arredondo
- IPICYT, División de Biología Molecular, Camino a la Presa San José 2055, C.P. 78216, San Luis Potosí, San Luis Potosí, Mexico
| | - Lina Riego-Ruíz
- IPICYT, División de Biología Molecular, Camino a la Presa San José 2055, C.P. 78216, San Luis Potosí, San Luis Potosí, Mexico
| | - Alexander DeLuna
- LANGEBIO: Laboratorio Nacional de Genomica para la Biodiversidad, Km 9.6 Libramiento Norte Carretera León, C.P. 36821 Irapuato, Guanajuato, Mexico
| | - Alejandro De Las Peñas
- IPICYT, División de Biología Molecular, Camino a la Presa San José 2055, C.P. 78216, San Luis Potosí, San Luis Potosí, Mexico
| | - Irene Castaño
- IPICYT, División de Biología Molecular, Camino a la Presa San José 2055, C.P. 78216, San Luis Potosí, San Luis Potosí, Mexico
| | - Mónica R Calera
- Instituto de Física, Universidad Autónoma de San Luis Potosí, Manuel Nava 6, Zona Univesitaria, C.P. 78290, San Luis Potosí, San Luis Potosí, Mexico.
| | - Roberto Sánchez-Olea
- Instituto de Física, Universidad Autónoma de San Luis Potosí, Manuel Nava 6, Zona Univesitaria, C.P. 78290, San Luis Potosí, San Luis Potosí, Mexico.
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