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Naeem ul Hassan M, Zainal Z, Ismail I. Plant kelch containing F-box proteins: structure, evolution and functions. RSC Adv 2015. [DOI: 10.1039/c5ra01875g] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Kelch repeat containing F-box proteins; a review on the progress of the research on these plant specific signalling proteins.
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Affiliation(s)
- M. Naeem ul Hassan
- School of Bioscience and Biotechnology
- Faculty of Science and Technology
- University Kebangsaan Malaysia
- Bangi, 43600
- Malaysia
| | - Zamri Zainal
- School of Bioscience and Biotechnology
- Faculty of Science and Technology
- University Kebangsaan Malaysia
- Bangi, 43600
- Malaysia
| | - Ismanizan Ismail
- School of Bioscience and Biotechnology
- Faculty of Science and Technology
- University Kebangsaan Malaysia
- Bangi, 43600
- Malaysia
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Hirano T, Murata T, Hayashi T. Physiological significance of recombination-activating gene 1 in neuronal death, especially optic neuropathy. FEBS J 2014; 282:129-41. [PMID: 25312244 DOI: 10.1111/febs.13109] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 08/28/2014] [Accepted: 10/10/2014] [Indexed: 12/20/2022]
Abstract
Although the transcription factor nuclear factor-κB (NF-κB) is known to regulate cell death and survival, its precise role in cell death within the central nervous system remains unknown. We previously reported that mice with a homozygous deficiency for NF-κBp50 spontaneously develop optic neuropathy. The aim of the present study was to demonstrate the expression and activation of the proapoptotic factor(s) that mediate optic neuropathy in p50-deficient mice. Recombination-activating gene (Rag) 1 is known to activate the recombination of immunoglobulin V(D)J. In this study, experiments with genetically engineered mice revealed the involvement of Rag1 expression in apoptosis of Brn3a-positive retinal ganglion cells, and also demonstrated the specific effect of p50 deficiency on the activation of Rag1 gene transcription. Furthermore, genetic analysis of murine neuronal stem-like cells clarified the biological significance of Rag1 in N-methyl-D-aspartate-induced neuronal apoptosis. We also detected the apoptosis-regulating factors Bax and cleaved caspase 3, 8 and 9 in HEK293 cells transfected-molecule of Rag1, and a human histological examination revealed the expression of Rag1 in retinal ganglion cells. The results of the present study indicate that Rag1 plays a role in optic neuropathy as a proapoptotic candidate in p50-deficient mice. This finding may lead to new therapeutic targets in optic neuropathy.
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Affiliation(s)
- Takao Hirano
- Department of Ophthalmology, Shinshu University Graduate School of Medicine, Matsumoto, Nagano, Japan; Department of Immunology and Infectious Disease, Shinshu University Graduate School of Medicine, Matsumoto, Nagano, Japan
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Female-dependent impaired fear memory of adult rats induced by maternal separation, and screening of possible related genes in the hippocampal CA1. Behav Brain Res 2014; 267:111-8. [DOI: 10.1016/j.bbr.2014.03.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 03/14/2014] [Accepted: 03/15/2014] [Indexed: 12/29/2022]
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Abstract
An essential link between the kidney and blood pressure control has long been known. Here, we review evidence supporting the premise that an impaired capacity of the kidney to excrete sodium in response to elevated blood pressure is a major contributor to hypertension, irrespective of the initiating cause. In this regard, recent work suggests that novel pathways controlling key sodium transporters in kidney epithelia have a critical impact on hypertension pathogenesis, supporting a model in which impaired renal sodium excretion is a final common pathway through which vascular, neural, and inflammatory responses raise blood pressure. We also address recent findings calling into question long-standing notions regarding the relationship between sodium intake and changes in body fluid volume. Expanded understanding of the role of the kidney as both a cause and target of hypertension highlights key aspects of pathophysiology and may lead to identification of new strategies for prevention and treatment.
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Insights in cullin 3/WNK4 and its relationship to blood pressure regulation and electrolyte homeostasis. Cell Signal 2014; 26:1166-72. [DOI: 10.1016/j.cellsig.2014.01.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 01/31/2014] [Indexed: 11/18/2022]
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Perissinotti PP, Ethington EG, Cribbs L, Koob MD, Martin J, Piedras-Rentería ES. Down-regulation of endogenous KLHL1 decreases voltage-gated calcium current density. Cell Calcium 2014; 55:269-80. [PMID: 24703904 DOI: 10.1016/j.ceca.2014.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Revised: 03/04/2014] [Accepted: 03/09/2014] [Indexed: 10/25/2022]
Abstract
The actin-binding protein Kelch-like 1 (KLHL1) can modulate voltage-gated calcium channels in vitro. KLHL1 interacts with actin and with the pore-forming subunits of Cav2.1 and CaV3.2 calcium channels, resulting in up-regulation of P/Q and T-type current density. Here we tested whether endogenous KLHL1 modulates voltage gated calcium currents in cultured hippocampal neurons by down-regulating the expression of KLHL1 via adenoviral delivery of shRNA targeted against KLHL1 (shKLHL1). Control adenoviruses did not affect any of the neuronal properties measured, yet down-regulation of KLHL1 resulted in HVA current densities ~68% smaller and LVA current densities 44% smaller than uninfected controls, with a concomitant reduction in α(1A) and α(1H) protein levels. Biophysical analysis and western blot experiments suggest Ca(V)3.1 and 3.3 currents are also present in shKLHL1-infected neurons. Synapsin I levels, miniature postsynaptic current frequency, and excitatory and inhibitory synapse number were reduced in KLHL1 knockdown. This study corroborates the physiological role of KLHL1 as a calcium channel modulator and demonstrates a novel, presynaptic role.
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Affiliation(s)
- Paula P Perissinotti
- Cell and Molecular Physiology Department, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA
| | - Elizabeth G Ethington
- Cell and Molecular Physiology Department, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA
| | - Leanne Cribbs
- Office of Research Services, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA
| | - Michael D Koob
- Institute for Translational Neuroscience, Department of Lab Medicine & Pathology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jody Martin
- Cell and Molecular Physiology Department, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA; Neuroscience Institute, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA
| | - Erika S Piedras-Rentería
- Cell and Molecular Physiology Department, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA; Neuroscience Institute, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA.
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57
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Uchida S, Sohara E, Rai T, Sasaki S. Regulation of with-no-lysine kinase signaling by Kelch-like proteins. Biol Cell 2014; 106:45-56. [PMID: 24313290 PMCID: PMC4162998 DOI: 10.1111/boc.201300069] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Accepted: 12/03/2013] [Indexed: 12/17/2022]
Abstract
In 2001, with-no-lysine (WNK) kinases were identified as the genes responsible for the human hereditary hypertensive disease pseudohypoaldosteronism type II (PHAII). It took a further 6 years to clarify that WNK kinases participate in a signaling cascade with oxidative stress-responsive gene 1 (OSR1), Ste20-related proline-alanine-rich kinase (SPAK), and thiazide-sensitive NaCl cotransporter (NCC) in the kidney and the constitutive activation of this signaling cascade is the molecular basis of PHAII. Since this discovery, the WNK-OSR1/SPAK-NCC signaling cascade has been shown to be involved not only in PHAII but also in the regulation of blood pressure under normal and pathogenic conditions, such as hyperinsulinemia. However, the molecular mechanisms of WNK kinase regulation by dietary and hormonal factors and by PHAII-causing mutations remain poorly understood. In 2012, two additional genes responsible for PHAII, Kelch-like 3 (KLHL3) and Cullin3, were identified. At the time of their discovery, the molecular mechanisms underlying the interaction between these genes and their involvement in PHAII were unknown. Here we review the pathophysiological roles of the WNK signaling cascade clarified to date and introduce a new mechanism of WNK kinase regulation by KLHL3 and Cullin3, which provides insight on previously unknown mechanisms of WNK kinase regulation.
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Affiliation(s)
- Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
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Ariey F, Witkowski B, Amaratunga C, Beghain J, Langlois AC, Khim N, Kim S, Duru V, Bouchier C, Ma L, Lim P, Leang R, Duong S, Sreng S, Suon S, Chuor CM, Bout DM, Ménard S, Rogers WO, Genton B, Fandeur T, Miotto O, Ringwald P, Le Bras J, Berry A, Barale JC, Fairhurst RM, Benoit-Vical F, Mercereau-Puijalon O, Ménard D. A molecular marker of artemisinin-resistant Plasmodium falciparum malaria. Nature 2014; 505:50-5. [PMID: 24352242 PMCID: PMC5007947 DOI: 10.1038/nature12876] [Citation(s) in RCA: 1419] [Impact Index Per Article: 141.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 11/12/2013] [Indexed: 12/24/2022]
Abstract
Plasmodium falciparum resistance to artemisinin derivatives in southeast Asia threatens malaria control and elimination activities worldwide. To monitor the spread of artemisinin resistance, a molecular marker is urgently needed. Here, using whole-genome sequencing of an artemisinin-resistant parasite line from Africa and clinical parasite isolates from Cambodia, we associate mutations in the PF3D7_1343700 kelch propeller domain ('K13-propeller') with artemisinin resistance in vitro and in vivo. Mutant K13-propeller alleles cluster in Cambodian provinces where resistance is prevalent, and the increasing frequency of a dominant mutant K13-propeller allele correlates with the recent spread of resistance in western Cambodia. Strong correlations between the presence of a mutant allele, in vitro parasite survival rates and in vivo parasite clearance rates indicate that K13-propeller mutations are important determinants of artemisinin resistance. K13-propeller polymorphism constitutes a useful molecular marker for large-scale surveillance efforts to contain artemisinin resistance in the Greater Mekong Subregion and prevent its global spread.
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Affiliation(s)
- Frédéric Ariey
- 1] Institut Pasteur, Parasite Molecular Immunology Unit, 75724 Paris Cedex 15, France [2] Centre National de la Recherche Scientifique, Unité de Recherche Associée 2581, 75724 Paris Cedex 15, France [3] Institut Pasteur, Genetics and Genomics of Insect Vectors Unit, 75724 Paris Cedex 15, France (F.A.); Institut Pasteur, Functional Genetics of Infectious Diseases Unit, 75724 Paris Cedex 15, France (J.B.); Centre de Physiopathologie de Toulouse-Purpan, Institut National de la Santé et de la Recherche Médicale UMR1043, Centre National de la Recherche Scientifique UMR5282, Université Toulouse III, 31024 Toulouse Cedex 3, France Institut Pasteur, Unité de Biologie et Génétique du Paludisme, Team Malaria Targets and Drug Development, 75724 Paris Cedex 15, France (J.-C.B.)
| | - Benoit Witkowski
- Institut Pasteur du Cambodge, Malaria Molecular Epidemiology Unit, Phnom Penh, Cambodia
| | - Chanaki Amaratunga
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Johann Beghain
- 1] Institut Pasteur, Parasite Molecular Immunology Unit, 75724 Paris Cedex 15, France [2] Centre National de la Recherche Scientifique, Unité de Recherche Associée 2581, 75724 Paris Cedex 15, France [3] Institut Pasteur, Genetics and Genomics of Insect Vectors Unit, 75724 Paris Cedex 15, France (F.A.); Institut Pasteur, Functional Genetics of Infectious Diseases Unit, 75724 Paris Cedex 15, France (J.B.); Centre de Physiopathologie de Toulouse-Purpan, Institut National de la Santé et de la Recherche Médicale UMR1043, Centre National de la Recherche Scientifique UMR5282, Université Toulouse III, 31024 Toulouse Cedex 3, France Institut Pasteur, Unité de Biologie et Génétique du Paludisme, Team Malaria Targets and Drug Development, 75724 Paris Cedex 15, France (J.-C.B.)
| | - Anne-Claire Langlois
- 1] Institut Pasteur, Parasite Molecular Immunology Unit, 75724 Paris Cedex 15, France [2] Centre National de la Recherche Scientifique, Unité de Recherche Associée 2581, 75724 Paris Cedex 15, France
| | - Nimol Khim
- Institut Pasteur du Cambodge, Malaria Molecular Epidemiology Unit, Phnom Penh, Cambodia
| | - Saorin Kim
- Institut Pasteur du Cambodge, Malaria Molecular Epidemiology Unit, Phnom Penh, Cambodia
| | - Valentine Duru
- Institut Pasteur du Cambodge, Malaria Molecular Epidemiology Unit, Phnom Penh, Cambodia
| | - Christiane Bouchier
- Institut Pasteur, Plate-forme Génomique, Département Génomes et Génétique, 75724 Paris Cedex 15, France
| | - Laurence Ma
- Institut Pasteur, Plate-forme Génomique, Département Génomes et Génétique, 75724 Paris Cedex 15, France
| | - Pharath Lim
- 1] Institut Pasteur du Cambodge, Malaria Molecular Epidemiology Unit, Phnom Penh, Cambodia [2] Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA [3] National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Rithea Leang
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Socheat Duong
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Sokunthea Sreng
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Seila Suon
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Char Meng Chuor
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Denis Mey Bout
- SSA WHO, Drug Monitoring in Cambodia, National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Sandie Ménard
- 1] Service de Parasitologie et Mycologie, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse Cedex 9, France [2] Institut Pasteur, Genetics and Genomics of Insect Vectors Unit, 75724 Paris Cedex 15, France (F.A.); Institut Pasteur, Functional Genetics of Infectious Diseases Unit, 75724 Paris Cedex 15, France (J.B.); Centre de Physiopathologie de Toulouse-Purpan, Institut National de la Santé et de la Recherche Médicale UMR1043, Centre National de la Recherche Scientifique UMR5282, Université Toulouse III, 31024 Toulouse Cedex 3, France Institut Pasteur, Unité de Biologie et Génétique du Paludisme, Team Malaria Targets and Drug Development, 75724 Paris Cedex 15, France (J.-C.B.)
| | | | - Blaise Genton
- Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland
| | - Thierry Fandeur
- 1] Institut Pasteur, Parasite Molecular Immunology Unit, 75724 Paris Cedex 15, France [2] Institut Pasteur du Cambodge, Malaria Molecular Epidemiology Unit, Phnom Penh, Cambodia
| | - Olivo Miotto
- 1] MRC Centre for Genomics and Global Health, University of Oxford, Oxford OX3 7BN, UK [2] Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok 10400, Thailand [3] Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Pascal Ringwald
- Global Malaria Program, World Health Organization, 1211 Geneva, Switzerland
| | - Jacques Le Bras
- Centre National de Référence du Paludisme, CHU Bichat-Claude Bernard, APHP, PRES Sorbonne Paris Cité, 75018 Paris, France
| | - Antoine Berry
- 1] Service de Parasitologie et Mycologie, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse Cedex 9, France [2] Institut Pasteur, Genetics and Genomics of Insect Vectors Unit, 75724 Paris Cedex 15, France (F.A.); Institut Pasteur, Functional Genetics of Infectious Diseases Unit, 75724 Paris Cedex 15, France (J.B.); Centre de Physiopathologie de Toulouse-Purpan, Institut National de la Santé et de la Recherche Médicale UMR1043, Centre National de la Recherche Scientifique UMR5282, Université Toulouse III, 31024 Toulouse Cedex 3, France Institut Pasteur, Unité de Biologie et Génétique du Paludisme, Team Malaria Targets and Drug Development, 75724 Paris Cedex 15, France (J.-C.B.)
| | - Jean-Christophe Barale
- 1] Institut Pasteur, Parasite Molecular Immunology Unit, 75724 Paris Cedex 15, France [2] Centre National de la Recherche Scientifique, Unité de Recherche Associée 2581, 75724 Paris Cedex 15, France [3] Institut Pasteur, Genetics and Genomics of Insect Vectors Unit, 75724 Paris Cedex 15, France (F.A.); Institut Pasteur, Functional Genetics of Infectious Diseases Unit, 75724 Paris Cedex 15, France (J.B.); Centre de Physiopathologie de Toulouse-Purpan, Institut National de la Santé et de la Recherche Médicale UMR1043, Centre National de la Recherche Scientifique UMR5282, Université Toulouse III, 31024 Toulouse Cedex 3, France Institut Pasteur, Unité de Biologie et Génétique du Paludisme, Team Malaria Targets and Drug Development, 75724 Paris Cedex 15, France (J.-C.B.)
| | - Rick M Fairhurst
- 1] Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA [2]
| | - Françoise Benoit-Vical
- 1] Centre National de la Recherche Scientifique, Laboratoire de Chimie de Coordination UPR8241, 31077 Toulouse Cedex 4, France [2] Université de Toulouse, UPS, Institut National Polytechnique de Toulouse, 31077 Toulouse Cedex 4, France [3]
| | - Odile Mercereau-Puijalon
- 1] Institut Pasteur, Parasite Molecular Immunology Unit, 75724 Paris Cedex 15, France [2] Centre National de la Recherche Scientifique, Unité de Recherche Associée 2581, 75724 Paris Cedex 15, France [3]
| | - Didier Ménard
- 1] Institut Pasteur du Cambodge, Malaria Molecular Epidemiology Unit, Phnom Penh, Cambodia [2]
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Brandt W, Backenköhler A, Schulze E, Plock A, Herberg T, Roese E, Wittstock U. Molecular models and mutational analyses of plant specifier proteins suggest active site residues and reaction mechanism. PLANT MOLECULAR BIOLOGY 2014; 84:173-88. [PMID: 23999604 DOI: 10.1007/s11103-013-0126-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 08/27/2013] [Indexed: 05/08/2023]
Abstract
As components of the glucosinolate-myrosinase system, specifier proteins contribute to the diversity of chemical defenses that have evolved in plants of the Brassicales order as a protection against herbivores and pathogens. Glucosinolates are thioglucosides that are stored separately from their hydrolytic enzymes, myrosinases, in plant tissue. Upon tissue disruption, glucosinolates are hydrolyzed by myrosinases yielding instable aglucones that rearrange to form defensive isothiocyanates. In the presence of specifier proteins, other products, namely simple nitriles, epithionitriles and organic thiocyanates, can be formed instead of isothiocyanates depending on the glucosinolate side chain structure and the type of specifier protein. The biochemical role of specifier proteins is largely unresolved. We have used two thiocyanate-forming proteins and one epithiospecifier protein with different substrate/product specificities to develop molecular models that, in conjunction with mutational analyses, allow us to propose an active site and docking arrangements with glucosinolate aglucones that may explain some of the differences in specifier protein specificities. Furthermore, quantum-mechanical calculations support a reaction mechanism for benzylthiocyanate formation including a catalytic role of the TFP involved. These results may serve as a basis for further theoretical and experimental investigations of the mechanisms of glucosinolate breakdown that will also help to better understand the evolution of specifier proteins from ancestral proteins with functions outside glucosinolate metabolism.
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Affiliation(s)
- Wolfgang Brandt
- Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120, Halle (Saale), Germany
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Chen Y, Xu Y, Luo W, Li W, Chen N, Zhang D, Chong K. The F-box protein OsFBK12 targets OsSAMS1 for degradation and affects pleiotropic phenotypes, including leaf senescence, in rice. PLANT PHYSIOLOGY 2013; 163:1673-85. [PMID: 24144792 PMCID: PMC3850201 DOI: 10.1104/pp.113.224527] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 10/16/2013] [Indexed: 05/18/2023]
Abstract
Leaf senescence is related to the grain-filling rate and grain weight in cereals. Many components involved in senescence regulation at either the genetic or physiological level are known. However, less is known about molecular regulation mechanisms. Here, we report that OsFBK12 (an F-box protein containing a Kelch repeat motif) interacts with S-ADENOSYL-l-METHIONINE SYNTHETASE1 (SAMS1) to regulate leaf senescence and seed size as well as grain number in rice (Oryza sativa). Yeast two-hybrid, pull-down, and bimolecular fluorescence complementation assays indicate that OsFBK12 interacts with Oryza sativa S-PHASE KINASE-ASSOCIATED PROTEIN1-LIKE PROTEIN and with OsSAMS1. Biochemical and physiological data showed that OsFBK12 targets OsSAMS1 for degradation. OsFBK12-RNA interference lines and OsSAMS1 overexpression lines showed increased ethylene levels, while OsFBK12-OX lines and OsSAMS1-RNA interference plants exhibited decreased ethylene. Phenotypically, overexpression of OsFBK12 led to a delay in leaf senescence and germination and increased seed size, whereas knockdown lines of either OsFBK12 or OsSAMS1 promoted the senescence program. Our results suggest that OsFBK12 is involved in the 26S proteasome pathway by interacting with Oryza sativa S-PHASE KINASE-ASSOCIATED PROTEIN1-LIKE PROTEIN and that it targets the substrate OsSAMS1 for degradation, triggering changes in ethylene levels for the regulation of leaf senescence and grain size. These data have potential applications in the molecular breeding of rice.
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Bowlin KM, Embree LJ, Garry MG, Garry DJ, Shi X. Kbtbd5 is regulated by MyoD and restricted to the myogenic lineage. Differentiation 2013; 86:184-91. [DOI: 10.1016/j.diff.2013.08.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 08/04/2013] [Accepted: 08/29/2013] [Indexed: 12/15/2022]
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Mutations in KLHL40 are a frequent cause of severe autosomal-recessive nemaline myopathy. Am J Hum Genet 2013; 93:6-18. [PMID: 23746549 DOI: 10.1016/j.ajhg.2013.05.004] [Citation(s) in RCA: 152] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 04/25/2013] [Accepted: 05/03/2013] [Indexed: 11/22/2022] Open
Abstract
Nemaline myopathy (NEM) is a common congenital myopathy. At the very severe end of the NEM clinical spectrum are genetically unresolved cases of autosomal-recessive fetal akinesia sequence. We studied a multinational cohort of 143 severe-NEM-affected families lacking genetic diagnosis. We performed whole-exome sequencing of six families and targeted gene sequencing of additional families. We identified 19 mutations in KLHL40 (kelch-like family member 40) in 28 apparently unrelated NEM kindreds of various ethnicities. Accounting for up to 28% of the tested individuals in the Japanese cohort, KLHL40 mutations were found to be the most common cause of this severe form of NEM. Clinical features of affected individuals were severe and distinctive and included fetal akinesia or hypokinesia and contractures, fractures, respiratory failure, and swallowing difficulties at birth. Molecular modeling suggested that the missense substitutions would destabilize the protein. Protein studies showed that KLHL40 is a striated-muscle-specific protein that is absent in KLHL40-associated NEM skeletal muscle. In zebrafish, klhl40a and klhl40b expression is largely confined to the myotome and skeletal muscle, and knockdown of these isoforms results in disruption of muscle structure and loss of movement. We identified KLHL40 mutations as a frequent cause of severe autosomal-recessive NEM and showed that it plays a key role in muscle development and function. Screening of KLHL40 should be a priority in individuals who are affected by autosomal-recessive NEM and who present with prenatal symptoms and/or contractures and in all Japanese individuals with severe NEM.
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Takahashi D, Mori T, Wakabayashi M, Mori Y, Susa K, Zeniya M, Sohara E, Rai T, Sasaki S, Uchida S. KLHL2 interacts with and ubiquitinates WNK kinases. Biochem Biophys Res Commun 2013; 437:457-62. [PMID: 23838290 DOI: 10.1016/j.bbrc.2013.06.104] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 06/27/2013] [Indexed: 01/29/2023]
Abstract
Mutations in the WNK1 and WNK4 genes result in an inherited hypertensive disease, pseudohypoaldosteronism type II (PHAII). Recently, the KLHL3 and Cullin3 genes were also identified as responsible genes for PHAII. Although we have reported that WNK4 is a substrate for the KLHL3-Cullin3 E3 ligase complex, it is not clear whether all of the WNK isoforms are regulated only by KLHL3. To explore the interaction of WNKs and other Kelch-like proteins, we focused on KLHL2 (Mayven), a human homolog of Drosophila Kelch that shares the highest similarity with KLHL3. We found that KLHL2, as well as KLHL3, was co-immunoprecipitated with all four WNK isoforms. The direct interaction of KLHL2 with WNKs was confirmed on fluorescence correlation spectroscopy. Co-expression of KLHL2 and Cullin3 decreased the abundance of WNK1, WNK3 and WNK4 within HEK293T cells, and a significant increase of WNK4 ubiquitination by KLHL2 and Cullin3 was observed both in HEK293T cells and in an in vitro ubiquitination assay. These results suggest that KLHL2-Cullin3 also functions as an E3-ligase for WNK isoforms within the body.
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Affiliation(s)
- Daiei Takahashi
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Japan
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Kelch-like 3 and Cullin 3 regulate electrolyte homeostasis via ubiquitination and degradation of WNK4. Proc Natl Acad Sci U S A 2013; 110:7838-43. [PMID: 23576762 DOI: 10.1073/pnas.1304592110] [Citation(s) in RCA: 180] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Pseudohypoaldosteronism type II (PHAII) is a rare Mendelian syndrome featuring hypertension and hyperkalemia resulting from constitutive renal salt reabsorption and impaired K(+) secretion. Recently, mutations in Kelch-like 3 (KLHL3) and Cullin 3 (CUL3), components of an E3 ubiquitin ligase complex, were found to cause PHAII, suggesting that loss of this complex's ability to target specific substrates for ubiquitination leads to PHAII. By MS and coimmunoprecipitation, we show that KLHL3 normally binds to WNK1 and WNK4, members of WNK (with no lysine) kinase family that have previously been found mutated in PHAII. We show that this binding leads to ubiquitination, including polyubiquitination, of at least 15 specific sites in WNK4, resulting in reduced WNK4 levels. Dominant disease-causing mutations in KLHL3 and WNK4 both impair WNK4 binding, ubiquitination, and degradation. WNK4 normally induces clearance of the renal outer medullary K(+) channel (ROMK) from the cell surface. We show that WT but not mutant KLHL3 inhibits WNK4-induced reduction of ROMK level. We show that PHAII-causing mutations in WNK4 lead to a marked increase in WNK4 protein levels in the kidney in vivo. These findings demonstrate that CUL3-RING (really interesting new gene) ligases that contain KLHL3 target ubiquitination of WNK4 and thereby regulate WNK4 levels, which in turn regulate levels of ROMK. These findings reveal a specific role of CUL3 and KLHL3 in electrolyte homeostasis and provide a molecular explanation for the effects of disease-causing mutations in both KLHL3 and WNK4.
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66
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Canning P, Cooper CDO, Krojer T, Murray JW, Pike ACW, Chaikuad A, Keates T, Thangaratnarajah C, Hojzan V, Marsden BD, Gileadi O, Knapp S, von Delft F, Bullock AN. Structural basis for Cul3 protein assembly with the BTB-Kelch family of E3 ubiquitin ligases. J Biol Chem 2013; 288:7803-7814. [PMID: 23349464 PMCID: PMC3597819 DOI: 10.1074/jbc.m112.437996] [Citation(s) in RCA: 206] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Cullin-RING ligases are multisubunit E3 ubiquitin ligases that recruit substrate-specific adaptors to catalyze protein ubiquitylation. Cul3-based Cullin-RING ligases are uniquely associated with BTB adaptors that incorporate homodimerization, Cul3 assembly, and substrate recognition into a single multidomain protein, of which the best known are BTB-BACK-Kelch domain proteins, including KEAP1. Cul3 assembly requires a BTB protein “3-box” motif, analogous to the F-box and SOCS box motifs of other Cullin-based E3s. To define the molecular basis for this assembly and the overall architecture of the E3, we determined the crystal structures of the BTB-BACK domains of KLHL11 both alone and in complex with Cul3, along with the Kelch domain structures of KLHL2 (Mayven), KLHL7, KLHL12, and KBTBD5. We show that Cul3 interaction is dependent on a unique N-terminal extension sequence that packs against the 3-box in a hydrophobic groove centrally located between the BTB and BACK domains. Deletion of this N-terminal region results in a 30-fold loss in affinity. The presented data offer a model for the quaternary assembly of this E3 class that supports the bivalent capture of Nrf2 and reveals potential new sites for E3 inhibitor design.
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Affiliation(s)
- Peter Canning
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | | | - Tobias Krojer
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - James W Murray
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Ashley C W Pike
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Apirat Chaikuad
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Tracy Keates
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | | | - Viktorija Hojzan
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Brian D Marsden
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Opher Gileadi
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Stefan Knapp
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Frank von Delft
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Alex N Bullock
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom.
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67
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Liman R, Facey PD, van Keulen G, Dyson PJ, Del Sol R. A laterally acquired galactose oxidase-like gene is required for aerial development during osmotic stress in Streptomyces coelicolor. PLoS One 2013; 8:e54112. [PMID: 23326581 PMCID: PMC3543389 DOI: 10.1371/journal.pone.0054112] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 12/10/2012] [Indexed: 12/25/2022] Open
Abstract
Phylogenetic reconstruction revealed that most Actinobacterial orthologs of S. coelicolor SCO2837, encoding a metal-dependent galactose oxidase-like protein, are found within Streptomyces and were probably acquired by horizontal gene transfer from fungi. Disruption of SCO2837 (glxA) caused a conditional bld phenotype that could not be reversed by extracellular complementation. Studies aimed at characterising the regulation of expression of glxA showed that it is not a target for other bld genes. We provide evidence that glxA is required for osmotic adaptation, although independently from the known osmotic stress response element SigB. glxA has been predicted to be part of an operon with the transcription unit comprising the upstream cslA gene and glxA. However, both phenotypic and expression studies indicate that it is also expressed from an independent promoter region internal to cslA. GlxA displays an in situ localisation pattern similar to that one observed for CslA at hyphal tips, but localisation of the former is independent of the latter. The functional role of GlxA in relation to CslA is discussed.
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Affiliation(s)
- Recep Liman
- Faculty of Science, Department of Genetics, Usak University, Usak, Turkey
| | - Paul D. Facey
- Institute of Life Science, College of Medicine, Swansea University, Singleton Park, Swansea, United Kingdom
| | - Geertje van Keulen
- Institute of Life Science, College of Medicine, Swansea University, Singleton Park, Swansea, United Kingdom
| | - Paul J. Dyson
- Institute of Life Science, College of Medicine, Swansea University, Singleton Park, Swansea, United Kingdom
| | - Ricardo Del Sol
- Institute of Life Science, College of Medicine, Swansea University, Singleton Park, Swansea, United Kingdom
- * E-mail:
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68
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Feiner N, Murakami Y, Breithut L, Mazan S, Meyer A, Kuraku S. Saltatory evolution of the ectodermal neural cortex gene family at the vertebrate origin. Genome Biol Evol 2013; 5:1485-502. [PMID: 23843192 PMCID: PMC3762194 DOI: 10.1093/gbe/evt104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/04/2013] [Indexed: 02/06/2023] Open
Abstract
The ectodermal neural cortex (ENC) gene family, whose members are implicated in neurogenesis, is part of the kelch repeat superfamily. To date, ENC genes have been identified only in osteichthyans, although other kelch repeat-containing genes are prevalent throughout bilaterians. The lack of elaborate molecular phylogenetic analysis with exhaustive taxon sampling has obscured the possible link of the establishment of this gene family with vertebrate novelties. In this study, we identified ENC homologs in diverse vertebrates by means of database mining and polymerase chain reaction screens. Our analysis revealed that the ENC3 ortholog was lost in the basal eutherian lineage through single-gene deletion and that the triplication between ENC1, -2, and -3 occurred early in vertebrate evolution. Including our original data on the catshark and the zebrafish, our comparison revealed high conservation of the pleiotropic expression pattern of ENC1 and shuffling of expression domains between ENC1, -2, and -3. Compared with many other gene families including developmental key regulators, the ENC gene family is unique in that conventional molecular phylogenetic inference could identify no obvious invertebrate ortholog. This suggests a composite nature of the vertebrate-specific gene repertoire, consisting not only of de novo genes introduced at the vertebrate origin but also of long-standing genes with no apparent invertebrate orthologs. Some of the latter, including the ENC gene family, may be too rapidly evolving to provide sufficient phylogenetic signals marking orthology to their invertebrate counterparts. Such gene families that experienced saltatory evolution likely remain to be explored and might also have contributed to phenotypic evolution of vertebrates.
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Affiliation(s)
- Nathalie Feiner
- Chair for Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Germany
- International Max-Planck Research School (IMPRS) for Organismal Biology, University of Konstanz, Germany
| | - Yasunori Murakami
- Department of Biology, Faculty of Science, Ehime University, Matsuyama, Japan
| | - Lisa Breithut
- Chair for Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Germany
| | - Sylvie Mazan
- Développement et Evolution des Vertébrés, UMR7150 CNRS and Université Paris 6, Station Biologique, Roscoff, France
| | - Axel Meyer
- Chair for Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Germany
- International Max-Planck Research School (IMPRS) for Organismal Biology, University of Konstanz, Germany
| | - Shigehiro Kuraku
- Chair for Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Germany
- International Max-Planck Research School (IMPRS) for Organismal Biology, University of Konstanz, Germany
- Present address: Genome Resource and Analysis Unit, RIKEN Center for Developmental Biology, Chuo-ku, Kobe, Japan
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69
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Oberg EA, Nifoussi SK, Gingras AC, Strack S. Selective proteasomal degradation of the B'β subunit of protein phosphatase 2A by the E3 ubiquitin ligase adaptor Kelch-like 15. J Biol Chem 2012; 287:43378-89. [PMID: 23135275 DOI: 10.1074/jbc.m112.420281] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Protein phosphatase 2A (PP2A), a ubiquitous and pleiotropic regulator of intracellular signaling, is composed of a core dimer (AC) bound to a variable (B) regulatory subunit. PP2A is an enzyme family of dozens of heterotrimers with different subcellular locations and cellular substrates dictated by the B subunit. B'β is a brain-specific PP2A regulatory subunit that mediates dephosphorylation of Ca(2+)/calmodulin-dependent protein kinase II and tyrosine hydroxylase. Unbiased proteomic screens for B'β interactors identified Cullin3 (Cul3), a scaffolding component of E3 ubiquitin ligase complexes, and the previously uncharacterized Kelch-like 15 (KLHL15). KLHL15 is one of ∼40 Kelch-like proteins, many of which have been identified as adaptors for the recruitment of substrates to Cul3-based E3 ubiquitin ligases. Here, we report that KLHL15-Cul3 specifically targets B'β to promote turnover of the PP2A subunit by ubiquitylation and proteasomal degradation. Comparison of KLHL15 and B'β tissue expression profiles suggests that the E3 ligase adaptor contributes to selective expression of the PP2A/B'β holoenzyme in the brain. We mapped KLHL15 residues critical for homodimerization as well as interaction with Cul3 and B'β. Explaining PP2A subunit selectivity, the divergent N terminus of B'β was found necessary and sufficient for KLHL15-mediated degradation, with Tyr-52 having an obligatory role. Although KLHL15 can interact with the PP2A/B'β heterotrimer, it only degrades B'β, thus promoting exchange with other regulatory subunits. E3 ligase adaptor-mediated control of PP2A holoenzyme composition thereby adds another layer of regulation to cellular dephosphorylation events.
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Affiliation(s)
- Elizabeth A Oberg
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, USA
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70
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Sekine Y, Hatanaka R, Watanabe T, Sono N, Iemura SI, Natsume T, Kuranaga E, Miura M, Takeda K, Ichijo H. The Kelch repeat protein KLHDC10 regulates oxidative stress-induced ASK1 activation by suppressing PP5. Mol Cell 2012; 48:692-704. [PMID: 23102700 DOI: 10.1016/j.molcel.2012.09.018] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Revised: 07/25/2012] [Accepted: 09/11/2012] [Indexed: 11/26/2022]
Abstract
Reactive oxygen species (ROS)-induced activation of Apoptosis signal-regulating kinase 1 (ASK1) plays crucial roles in oxidative stress-mediated cell death through the activation of the JNK and p38 MAPK pathways. However, the regulatory mechanism of ASK1 in the oxidative stress response remains to be elucidated. Here, we identified the kelch repeat protein, Slim, as an activator of ASK1 through a Drosophila misexpression screen. We also performed a proteomics screen and revealed that Kelch domain containing 10 (KLHDC10), a mammalian ortholog of Slim, interacted with Protein phosphatase 5 (PP5), which has been shown to inactivate ASK1 in response to ROS. KLHDC10 bound to the phosphatase domain of PP5 and suppressed its phosphatase activity. Moreover, KLHDC10 was required for H(2)O(2)-induced sustained activation of ASK1 and cell death in Neuro2A cells. These findings suggest that Slim/KLHDC10 is an activator of ASK1, contributing to oxidative stress-induced cell death through the suppression of PP5.
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Affiliation(s)
- Yusuke Sekine
- Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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71
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Krem MM, Luo P, Ing BI, Horwitz MS. The kelch protein KLHDC8B guards against mitotic errors, centrosomal amplification, and chromosomal instability. J Biol Chem 2012; 287:39083-93. [PMID: 22988245 DOI: 10.1074/jbc.m112.390088] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The malignant cell in classical Hodgkin lymphoma (HL) is the binucleated giant Reed-Sternberg cell. Chromosomal instability and mitotic errors may contribute to HL pathogenesis; one potential mitotic regulator is the kelch protein KLHDC8B, which localizes to the midbody, is expressed during mitosis, and is mutated in a subset of familial and sporadic HL. We report that disrupting KLHDC8B function in HeLa cells, B lymphoblasts, and fibroblasts leads to significant increases in multinucleation, multipolar mitoses, failed abscission, asymmetric segregation of daughter nuclei, formation of anucleated daughter cells, centrosomal amplification, and aneuploidy. We recapitulated the major pathologic features of the Reed-Sternberg cell and concluded that KLHDC8B is essential for mitotic integrity and maintenance of chromosomal stability. The significant impact of KLHDC8B implicates the central roles of mitotic regulation and chromosomal segregation in the pathogenesis of HL and provides a novel molecular mechanism for chromosomal instability in HL.
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Affiliation(s)
- Maxwell M Krem
- Department of Pathology and the Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, Washington 98109, USA.
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72
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Choe KP, Leung CK, Miyamoto MM. Unique structure and regulation of the nematode detoxification gene regulator, SKN-1: implications to understanding and controlling drug resistance. Drug Metab Rev 2012; 44:209-23. [PMID: 22656429 PMCID: PMC3398467 DOI: 10.3109/03602532.2012.684799] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Nematodes parasitize an alarming number of people and agricultural animals globally and cause debilitating morbidity and mortality. Anthelmintics have been the primary tools used to control parasitic nematodes for the past several decades, but drug resistance is becoming a major obstacle. Xenobiotic detoxification pathways defend against drugs and other foreign chemicals in diverse organisms, and evidence is accumulating that they play a role in mediating resistance to anthelmintics in nematodes. Related antioxidation pathways may also provide filarial parasites with protection against host free-radical-mediated immune responses. Upstream regulatory pathways have received almost no attention in nematode parasites, despite their potential to coregulate multiple detoxification and antioxidation genes. The nuclear eurythroid 2-related factor 2 (NRF2) transcription factor mediates inducible detoxification and antioxidation defenses in mammals, and recent studies have demonstrated that it promotes multidrug resistance in some human tumors. Recent studies in the free-living model nematode, Caenorhabditis elegans, have defined the homologous transcription factor, SKN-1, as a master regulator of detoxification and antioxidation genes. Despite similar functions, SKN-1 and NRF2 have important differences in structure and regulatory pathways. Protein alignment and phylogenetic analyses indicate that these differences are shared among many nematodes, making SKN-1 a candidate for specifically targeting nematode detoxification and antioxidation.
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Affiliation(s)
- Keith P Choe
- Department of Biology, University of Florida, Gainesville, FL 32611, USA.
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73
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Sambuughin N, Swietnicki W, Techtmann S, Matrosova V, Wallace T, Goldfarb L, Maynard E. KBTBD13 interacts with Cullin 3 to form a functional ubiquitin ligase. Biochem Biophys Res Commun 2012; 421:743-9. [PMID: 22542517 DOI: 10.1016/j.bbrc.2012.04.074] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 04/13/2012] [Indexed: 12/18/2022]
Abstract
Autosomal dominant mutations in BTB and Kelch domain containing 13 protein (KBTBD13) are associated with a new type of Nemaline Myopathy (NEM). NEM is a genetically heterogeneous group of muscle disorders. Mutations causing phenotypically distinct NEM variants have previously been identified in components of muscle thin filament. KBTBD13 is a muscle specific protein composed of an N terminal BTB domain and a C terminal Kelch-repeat domain. The function of this newly identified protein in muscle remained unknown. In this study, we show that KBTBD13 interacts with Cullin 3 (Cul3) and the BTB domain mediates this interaction. Using ubiquitination assays, we determined that KBTBD13 participates in the formation of a Cul3 based RING ubiquitin ligase (Cul3-RL) capable of ubiquitin conjugation. Confocal microscopy of transiently expressed KBTBD13 revealed its co-localization with ubiquitin. Taken together, our results demonstrate that KBTBD13 is a putative substrate adaptor for Cul3-RL that functions as a muscle specific ubiquitin ligase, and thereby implicate the ubiquitin proteasome pathway in the pathogenesis of KBTBD13-associated NEM.
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Affiliation(s)
- Nyamkhishig Sambuughin
- Department of Anesthesiology, Uniformed Services University, 4301 Jones Bridge Rd., Bethesda, MD 20814, USA.
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74
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Mutations in kelch-like 3 and cullin 3 cause hypertension and electrolyte abnormalities. Nature 2012; 482:98-102. [PMID: 22266938 PMCID: PMC3278668 DOI: 10.1038/nature10814] [Citation(s) in RCA: 462] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2011] [Accepted: 12/22/2011] [Indexed: 01/12/2023]
Abstract
Hypertension affects one billion people and is a principal reversible risk factor for cardiovascular disease. Pseudohypoaldosteronism type II (PHAII), a rare Mendelian syndrome featuring hypertension, hyperkalaemia and metabolic acidosis, has revealed previously unrecognized physiology orchestrating the balance between renal salt reabsorption and K(+) and H(+) excretion. Here we used exome sequencing to identify mutations in kelch-like 3 (KLHL3) or cullin 3 (CUL3) in PHAII patients from 41 unrelated families. KLHL3 mutations are either recessive or dominant, whereas CUL3 mutations are dominant and predominantly de novo. CUL3 and BTB-domain-containing kelch proteins such as KLHL3 are components of cullin-RING E3 ligase complexes that ubiquitinate substrates bound to kelch propeller domains. Dominant KLHL3 mutations are clustered in short segments within the kelch propeller and BTB domains implicated in substrate and cullin binding, respectively. Diverse CUL3 mutations all result in skipping of exon 9, producing an in-frame deletion. Because dominant KLHL3 and CUL3 mutations both phenocopy recessive loss-of-function KLHL3 mutations, they may abrogate ubiquitination of KLHL3 substrates. Disease features are reversed by thiazide diuretics, which inhibit the Na-Cl cotransporter in the distal nephron of the kidney; KLHL3 and CUL3 are expressed in this location, suggesting a mechanistic link between KLHL3 and CUL3 mutations, increased Na-Cl reabsorption, and disease pathogenesis. These findings demonstrate the utility of exome sequencing in disease gene identification despite the combined complexities of locus heterogeneity, mixed models of transmission and frequent de novo mutation, and establish a fundamental role for KLHL3 and CUL3 in blood pressure, K(+) and pH homeostasis.
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75
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Hermosa R, Botella L, Keck E, Jiménez JÁ, Montero-Barrientos M, Arbona V, Gómez-Cadenas A, Monte E, Nicolás C. The overexpression in Arabidopsis thaliana of a Trichoderma harzianum gene that modulates glucosidase activity, and enhances tolerance to salt and osmotic stresses. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:1295-1302. [PMID: 21466906 DOI: 10.1016/j.jplph.2011.01.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 12/21/2010] [Accepted: 01/10/2011] [Indexed: 05/30/2023]
Abstract
Using the TrichoEST database, generated in a previous functional genomics project from the beneficial filamentous fungus Trichoderma harzianum, a gene named Thkel1, which codes for a putative kelch-repeat protein, was isolated and characterized. Silencing of this gene in T. harzianum leads to a reduction of glucosidase activity and mycelial growth under abiotic stress conditions. Expression of this gene in Arabidopsis enhances plant tolerance to salt and osmotic stresses, accompanied by an increase in glucosidase activity and a reduction of abscisic acid levels compared to those observed in wild-type plants. Data presented throughout this article suggest the high value of T. harzianum as a source of genes able to facilitate the achievement of producing plants resistant to abiotic stresses without alteration of their phenotype.
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Affiliation(s)
- Rosa Hermosa
- Departamento de Microbiología y Genética, Centro Hispano-Luso de Investigaciones Agrarias (CIALE), Facultad de Farmacia, Universidad de Salamanca, C/Río Duero 12, Campus de Villamayor, 37185 Salamanca, Spain
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76
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Timms AE, Horwitz MS. KLHDC8B in Hodgkin lymphoma and possibly twinning. Commun Integr Biol 2011; 3:154-8. [PMID: 20585509 DOI: 10.4161/cib.3.2.10479] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Accepted: 10/29/2009] [Indexed: 11/19/2022] Open
Abstract
A key feature of Hodgkin lymphoma is that the malignant cells are binucleated, as a consequence of failed cytokinesis. We recently ascertained a family in which multiple cases of Hodgkin lymphoma had occurred among individuals who inherited a balanced chromosomal translocation. We cloned the translocation breakpoints and found that it disrupted a previously uncharacterized gene, KLHDC8B, encoding a Kelch family protein whose deficiency impairs cytokinesis and leads to binucleated cells. In other families we found a rare single nucleotide polymorphism affecting mitotic translation of KLHDC8B that was associated with and linked to Hodgkin lymphoma. Interestingly, the index family demonstrated an unusual frequency of twins, and there is a previously reported association between Hodgkin lymphoma and twins. Here we review the unusual genetic features of Hodgkin lymphoma, including gender concordance among siblings, and genetically test the hypothesis that KLHDC8B may participate in twinning by disrupting cytokinesis through impediment of polar body separation from oocytes.
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Affiliation(s)
- Andrew E Timms
- Department of Pathology; Institute for Stem Cell & Regenerative Medicine; University of Washington; Seattle, WA USA
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77
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Jia Y, Gu H, Wang X, Chen Q, Shi S, Zhang J, Ma L, Zhang H, Ma H. Molecular cloning and characterization of an F-box family gene CarF-box1 from chickpea (Cicer arietinum L.). Mol Biol Rep 2011; 39:2337-45. [PMID: 21667242 DOI: 10.1007/s11033-011-0984-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 05/28/2011] [Indexed: 11/30/2022]
Abstract
F-box protein family has been found to play important roles in plant development and abiotic stress responses via the ubiquitin pathway. In this study, an F-box gene CarF-box1 (for Cicer arietinum F-box gene 1, Genbank accession no. GU247510) was isolated based on a cDNA library constructed with chickpea seedling leaves treated by polyethylene glycol. CarF-box1 encoded a putative protein with 345 amino acids and contained no intron within genomic DNA sequence. CarF-box1 is a KFB-type F-box protein, having a conserved F-box domain in the N-terminus and a Kelch repeat domain in the C-terminus. CarF-box1 was localized in the nucleus. CarF-box1 exhibited organ-specific expression and showed different expression patterns during seed development and germination processes, especially strongly expressed in the blooming flowers. In the leaves, CarF-box1 could be significantly induced by drought stress and slightly induced by IAA treatment, while in the roots, CarF-box1 could be strongly induced by drought, salinity and methyl jasmonate stresses. Our results suggest that CarF-box1 encodes an F-box protein and may be involved in various plant developmental processes and abiotic stress responses.
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Affiliation(s)
- Yuying Jia
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
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78
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Park SK, Jeon YM, Son BS, Youn HS, Lee MY. Proteomic analysis of the differentially expressed proteins by airborne nanoparticles. J Appl Toxicol 2011; 31:463-70. [PMID: 21491466 DOI: 10.1002/jat.1658] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Accepted: 12/23/2010] [Indexed: 12/12/2022]
Abstract
Airborne nanoparticles with thermodynamic diameters less than 56 nm (PM(0.056)) were collected using a Moudi cascade impactor, and the differentially expressed proteins upon exposure to the airborne nanoparticles were identified in human bronchial epithelial cells. More than 600 protein spots were detected on the two-dimensional gel, and the identified 13 of these proteins showed notable changes. Nine were up-regulated and four were down-regulated following treatment with the airborne nanoparticles. Notably, malignant transformation-associated multiple forms of keratins, epigenetic regulation-related MBD1-containing chromatin associated factor 2, epithelial malignancy-related vimentin and exocytosis-related annexin A2 were changed upon exposure to airborne nanoparticle PM(0.056).
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Affiliation(s)
- Seul Ki Park
- Department of Medical Biotechnology, SoonChunHyang University, Asan, Chungnam, 336-600, Republic of Korea
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79
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McGowan PO, Hope TA, Meck WH, Kelsoe G, Williams CL. Impaired social recognition memory in recombination activating gene 1-deficient mice. Brain Res 2011; 1383:187-95. [PMID: 21354115 DOI: 10.1016/j.brainres.2011.02.054] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Revised: 02/14/2011] [Accepted: 02/15/2011] [Indexed: 10/18/2022]
Abstract
The recombination activating genes (RAGs) encode two enzymes that play key roles in the adaptive immune system. RAG1 and RAG2 mediate VDJ recombination, a process necessary for the maturation of B- and T-cells. Interestingly, RAG1 is also expressed in the brain, particularly in areas of high neural density such as the hippocampus, although its function is unknown. We tested evidence that RAG1 plays a role in brain function using a social recognition memory task, an assessment of the acquisition and retention of conspecific identity. In a first experiment, we found that RAG1-deficient mice show impaired social recognition memory compared to mice wildtype for the RAG1 allele. In a second experiment, by breeding to homogenize background genotype, we found that RAG1-deficient mice show impaired social recognition memory relative to heterozygous or RAG2-deficient littermates. Because RAG1 and RAG2 null mice are both immunodeficient, the results suggest that the memory impairment is not an indirect effect of immunological dysfunction. RAG1-deficient mice show normal habituation to non-socially derived odors and habituation to an open-field, indicating that the observed effect is not likely a result of a general deficit in habituation to novelty. These data trace the origin of the impairment in social recognition memory in RAG1-deficient mice to the RAG1 gene locus and implicate RAG1 in memory formation.
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Affiliation(s)
- Patrick O McGowan
- Department of Psychology and Neuroscience, Duke University, Durham, NC 27708, USA.
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80
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Schumann N, Navarro-Quezada A, Ullrich K, Kuhl C, Quint M. Molecular evolution and selection patterns of plant F-box proteins with C-terminal kelch repeats. PLANT PHYSIOLOGY 2011; 155:835-50. [PMID: 21119043 PMCID: PMC3032470 DOI: 10.1104/pp.110.166579] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The F-box protein superfamily represents one of the largest families in the plant kingdom. F-box proteins phylogenetically organize into numerous subfamilies characterized by their carboxyl (C)-terminal protein-protein interaction domain. Among the largest F-box protein subfamilies in plant genomes are those with C-terminal kelch repeats. In this study, we analyzed the phylogeny and evolution of F-box kelch proteins/genes (FBKs) in seven completely sequenced land plant genomes including a bryophyte, a lycophyte, monocots, and eudicots. While absent in prokaryotes, F-box kelch proteins are widespread in eukaryotes. Nonplant eukaryotes usually contain only a single FBK gene. In land plant genomes, however, FBKs expanded dramatically. Arabidopsis thaliana, for example, contains at least 103 F-box genes with well-conserved C-terminal kelch repeats. The construction of a phylogenetic tree based on the full-length amino acid sequences of the FBKs that we identified in the seven species enabled us to classify FBK genes into unstable/stable/superstable categories. In contrast to superstable genes, which are conserved across all seven species, kelch domains of unstable genes, which are defined as lineage specific, showed strong signatures of positive selection, indicating adaptational potential. We found evidence for conserved protein features such as binding affinities toward A. thaliana SKP1-like adaptor proteins and subcellular localization among closely related FBKs. Pseudogenization seems to occur only rarely, but differential transcriptional regulation of close relatives may result in subfunctionalization.
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81
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Sambuughin N, Yau KS, Olivé M, Duff RM, Bayarsaikhan M, Lu S, Gonzalez-Mera L, Sivadorai P, Nowak KJ, Ravenscroft G, Mastaglia FL, North KN, Ilkovski B, Kremer H, Lammens M, van Engelen BGM, Fabian V, Lamont P, Davis MR, Laing NG, Goldfarb LG. Dominant mutations in KBTBD13, a member of the BTB/Kelch family, cause nemaline myopathy with cores. Am J Hum Genet 2010; 87:842-7. [PMID: 21109227 DOI: 10.1016/j.ajhg.2010.10.020] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 10/09/2010] [Accepted: 10/20/2010] [Indexed: 12/11/2022] Open
Abstract
We identified a member of the BTB/Kelch protein family that is mutated in nemaline myopathy type 6 (NEM6), an autosomal-dominant neuromuscular disorder characterized by the presence of nemaline rods and core lesions in the skeletal myofibers. Analysis of affected families allowed narrowing of the candidate region on chromosome 15q22.31, and mutation screening led to the identification of a previously uncharacterized gene, KBTBD13, coding for a hypothetical protein and containing missense mutations that perfectly cosegregate with nemaline myopathy in the studied families. KBTBD13 contains a BTB/POZ domain and five Kelch repeats and is expressed primarily in skeletal and cardiac muscle. The identified disease-associated mutations, C.742C>A (p.Arg248Ser), c.1170G>C (p.Lys390Asn), and c.1222C>T (p.Arg408Cys), located in conserved domains of Kelch repeats, are predicted to disrupt the molecule's beta-propeller blades. Previously identified BTB/POZ/Kelch-domain-containing proteins have been implicated in a broad variety of biological processes, including cytoskeleton modulation, regulation of gene transcription, ubiquitination, and myofibril assembly. The functional role of KBTBD13 in skeletal muscle and the pathogenesis of NEM6 are subjects for further studies.
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82
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Mantzouranis L, Bagattini R, Souza GM. KeaA, a Dictyostelium Kelch-domain protein that regulates the response to stress and development. BMC DEVELOPMENTAL BIOLOGY 2010; 10:79. [PMID: 20670432 PMCID: PMC2920877 DOI: 10.1186/1471-213x-10-79] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Accepted: 07/29/2010] [Indexed: 11/25/2022]
Abstract
Background The protein kinase YakA is responsible for the growth arrest and induction of developmental processes that occur upon starvation of Dictyostelium cells. yakA- cells are aggregation deficient, have a faster cell cycle and are hypersensitive to oxidative and nitrosoative stress. With the aim of isolating members of the YakA pathway, suppressors of the death induced by nitrosoative stress in the yakA- cells were identified. One of the suppressor mutations occurred in keaA, a gene identical to DG1106 and similar to Keap1 from mice and the Kelch protein from Drosophila, among others that contain Kelch domains. Results A mutation in keaA suppresses the hypersensitivity to oxidative and nitrosoative stresses but not the faster growth phenotype of yakA- cells. The growth profile of keaA deficient cells indicates that this gene is necessary for growth. keaA deficient cells are more resistant to nitrosoative and oxidative stress and keaA is necessary for the production and detection of cAMP. A morphological analysis of keaA deficient cells during multicellular development indicated that, although the mutant is not absolutely deficient in aggregation, cells do not efficiently participate in the process. Gene expression analysis using cDNA microarrays of wild-type and keaA deficient cells indicated a role for KeaA in the regulation of the cell cycle and pre-starvation responses. Conclusions KeaA is required for cAMP signaling following stress. Our studies indicate a role for kelch proteins in the signaling that regulates the cell cycle and development in response to changes in the environmental conditions.
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Affiliation(s)
- Luciana Mantzouranis
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 05508-000 São Paulo, Brasil.
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83
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Hu J, Yuan W, Tang M, Wang Y, Fan X, Mo X, Li Y, Ying Z, Wan Y, Ocorr K, Bodmer R, Deng Y, Wu X. KBTBD7, a novel human BTB-kelch protein, activates transcriptional activities of SRE and AP-1. BMB Rep 2010; 43:17-22. [PMID: 20132730 DOI: 10.5483/bmbrep.2010.43.1.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this study, a novel member of BTB-kelch proteins, named KBTBD7, was cloned from a human embryonic heart cDNA library. The cDNA of KBTBD7 is 3,008 bp long and encodes a protein product of 684 amino acids (77.2 kD). This protein is highly conserved in evolution across different species. Western blot analysis indicates that a 77 kD protein specific for KBTBD7 is wildly expressed in all embryonic tissues examined. In COS-7 cells, KBTBD7 proteins are localized to the cytoplasm. KBTBD7 is a transcription activator when fused to GAL4 DNA-binding domain. Deletion analysis indicates that the BTB domain and kelch repeat motif are main regions for transcriptional activation. Overexpression of KBTBD7 in MCF-7 cells activates the transcriptional activities of activator protein-1 (AP-1) and serum response element (SRE), which can be relieved by siRNA. These results suggest that KBTBD7 proteins may act as a new transcriptional activator in mitogen-activated protein kinase (MAPK) signaling. [BMB reports 2010; 43(1): 17-22].
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Affiliation(s)
- Junjian Hu
- The Center For Heart Development, Key Lab of MOE for Development Biology and Protein Chemistry, College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, Peoples' Republic of China
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84
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Lee HL, Essani K. Differential susceptibility of human cancer cell lines to wild-type tanapoxvirus infection. Open Virol J 2010; 4:1-6. [PMID: 20461227 PMCID: PMC2866450 DOI: 10.2174/1874357901004010001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2009] [Revised: 02/10/2010] [Accepted: 02/23/2010] [Indexed: 11/24/2022] Open
Abstract
Tanapoxvirus (TPV) is a member of the genus Yatapoxvirus in the family Poxviridae and is endemic to equatorial Africa. This disease is restricted to human and non-human primates, producing a mild febrile illness characterized by a single or more rarely additional pock-like lesions on the extremities. While there are several studies elucidating the replication cycle and host range of TPV, there is currently no standardized investigation comparing the ability of TPV to successfully replicate in a variety of tumor cell lines. This study examined the cytopathic effect and calculated the efficiency of TPV replication in vitro using 14 different human cancer cell lines. TPV replicates efficiently in some human tumor cells, and is restricted in others when measured by viral titer at 7 days post infection. Results described here clearly demonstrate that TPV replication in one glioblastoma cell line (U-373), and one colorectal cancer cell line (HCT-116) is more productive than in owl monkey kidney cells (OMK). Replication in two renal cancer cell lines (ACHN and Caki-1) is also increased when compared to OMK. TPV infection produced the greatest change in cellular morphology in U-373 cells, and to a much lesser degree in the breast cancer cell lines T-47D and MCF-7, and in the ovarian cancer line SK-OV3. Negligible change was noted in glioblastoma line U-87, breast cancer line MDA-MB-435, osteosarcoma line HOS, melanoma line SK-MEL5, colorectal cancer line COLO205, and prostate cancer line PC3. The cell lines least permissive to TPV replication were the glioblastoma (U-87) and melanoma (SK-MEL5) cell lines.
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Affiliation(s)
- Hui Lin Lee
- Laboratory of Virology, Department of Biological Sciences, Western Michigan University, Kalamazoo, MI 49008, USA
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85
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Krem MM, Salipante SJ, Horwitz MS. Mutations in a gene encoding a midbody protein in binucleated Reed-Sternberg cells of Hodgkin lymphoma. Cell Cycle 2010; 9:670-5. [PMID: 20107318 DOI: 10.4161/cc.9.4.10780] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Classical Hodgkin lymphoma (cHL) is a cancer in which malignant "Reed-Sternberg" cells comprise just a fraction of the bulk of the tumor and are characteristically binucleated. We recently identified a novel gene, KLHDC8B, which appears responsible for some familial cases of cHL. KLHDC8B encodes a midbody kelch protein expressed during cytokinesis. Deficiency of KLHDC8B leads to binucleated cells, implicating its involvement in Reed-Sternberg cell formation. Interestingly, other cancer genes, such as BRCA1 and BRCA2, also encode proteins locating to the midbody during cytokinesis, even though their participation in other pathways has received greater attention. Midbody components may be an overlooked source of tumor suppressor genes.
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Affiliation(s)
- Maxwell M Krem
- Medical Oncology Program, Institute for Stem Cell & Regenerative Medicine, University of Washington, Seattle, WA, USA
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86
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Chaikam V, Karlson DT. Comparison of structure, function and regulation of plant cold shock domain proteins to bacterial and animal cold shock domain proteins. BMB Rep 2010; 43:1-8. [DOI: 10.5483/bmbrep.2010.43.1.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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87
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Sakaguchi A, Miyaji T, Tsuji G, Kubo Y. A Kelch repeat protein, Cokel1p, associates with microtubules and is involved in appressorium development in Colletotrichum orbiculare. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:103-111. [PMID: 19958143 DOI: 10.1094/mpmi-23-1-0103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Kelch repeat proteins are conserved in diverse organisms and some are known to mediate fundamental cellular functions. We isolated the gene CoKEL1, encoding a novel kelch repeat protein, from Colletotrichum orbiculare. Analysis of a cokel1 mutant indicated that CoKEL1 is involved in proper appressorium development and cell wall synthesis. Appressoria produced by cokel1 disruption mutants showed irregular shape and impairment of turgor generation and the mutant appressoria rarely penetrated to form infection hyphae in host epidermal cells. Accordingly, cokel1 mutants had reduced pathogenicity on host leaves compared with the wild type. Furthermore, the cokel1 mutant was more sensitive to cell-wall-degrading enzymes and showed altered labeling with the cell wall stain Calcofluor white. Cokel1p was localized on cortical and spindle microtubules in vegetative hyphae. These results suggest that Cokel1p is a microtubule-associated protein involved in infection-related morphogenesis and pathogenicity. This is the first report that a kelch repeat protein is required for the pathogenicity of a fungal plant pathogen.
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Affiliation(s)
- Ayumu Sakaguchi
- Laboratory of Plant Pathology, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto 606-8522, Japan
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88
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Kaspar JW, Niture SK, Jaiswal AK. Nrf2:INrf2 (Keap1) signaling in oxidative stress. Free Radic Biol Med 2009; 47:1304-9. [PMID: 19666107 PMCID: PMC2763938 DOI: 10.1016/j.freeradbiomed.2009.07.035] [Citation(s) in RCA: 1227] [Impact Index Per Article: 81.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 07/30/2009] [Accepted: 07/31/2009] [Indexed: 12/14/2022]
Abstract
Nrf2:INrf2 (Keap1) are cellular sensors of chemical- and radiation-induced oxidative and electrophilic stress. Nrf2 is a nuclear transcription factor that controls the expression and coordinated induction of a battery of defensive genes encoding detoxifying enzymes and antioxidant proteins. This is a mechanism of critical importance for cellular protection and cell survival. Nrf2 is retained in the cytoplasm by an inhibitor, INrf2 which functions as an adapter for Cul3/Rbx1-mediated degradation of Nrf2. In response to oxidative/electrophilic stress, Nrf2 is switched on and then off by distinct early and delayed mechanisms. Oxidative/electrophilic modification of INrf2 cysteine 151 and/or protein kinase C phosphorylation of Nrf2 serine 40 results in the escape or release of Nrf2 from INrf2. Nrf2 is stabilized and translocates to the nucleus, forms heterodimers with unknown proteins, and binds the antioxidant response element, which leads to coordinated activation of gene expression. It takes less than 15 min from the time of exposure to switch on nuclear import of Nrf2. This is followed by activation of a delayed mechanism that controls the switching off of Nrf2 activation of gene expression. GSK3beta phosphorylates Fyn at an unknown threonine residue(s), leading to the nuclear localization of Fyn. Fyn phosphorylates Nrf2 tyrosine 568, resulting in the nuclear export of Nrf2, binding with INrf2, and degradation of Nrf2. The switching on and off of Nrf2 protects cells against free radical damage, prevents apoptosis, and promotes cell survival.
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89
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Gray CH, McGarry LC, Spence HJ, Riboldi-Tunnicliffe A, Ozanne BW. Novel beta-propeller of the BTB-Kelch protein Krp1 provides a binding site for Lasp-1 that is necessary for pseudopodial extension. J Biol Chem 2009; 284:30498-507. [PMID: 19726686 PMCID: PMC2781604 DOI: 10.1074/jbc.m109.023259] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 08/19/2009] [Indexed: 11/06/2022] Open
Abstract
Kelch-related protein 1 (Krp1) is up-regulated in oncogene-transformed fibroblasts. The Kelch repeats interact directly with the actin-binding protein Lasp-1 in membrane ruffles at the tips of pseudopodia, where both proteins are necessary for pseudopodial elongation. Herein, we investigate the molecular basis for this interaction. Probing an array of overlapping decapeptides of Rattus norvegicus (Rat) Krp1 with recombinant Lasp-1 revealed two binding sites; one ((317)YDPMENECYLT(327)) precedes the first of five Kelch repeats, and the other ((563)TEVNDIWKYEDD(574)) is in the last of the five Kelch repeats. Mutational analysis established that both binding sites are necessary for Krp1-Lasp-1 interaction in vitro and function in vivo. The crystal structure of the C-terminal domain of rat Krp1 (amino acids 289-606) reveals that both binding sites are brought into close proximity by the formation of a novel six-bladed beta-propeller, where the first blade is not formed by a Kelch repeat.
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Affiliation(s)
- Christopher H Gray
- Invasion and Metastasis Laboratory, Beatson Institute for Cancer Research, Garscube Estate, Glasgow G61 1BD, Scotland, United Kingdom.
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90
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Mutations in a gene encoding a midbody kelch protein in familial and sporadic classical Hodgkin lymphoma lead to binucleated cells. Proc Natl Acad Sci U S A 2009; 106:14920-5. [PMID: 19706467 DOI: 10.1073/pnas.0904231106] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Classical Hodgkin lymphoma (cHL) is a malignancy of B-cell origin in which the neoplastic cells, known as "Reed-Sternberg" (RS) cells, are characteristically binucleated. Here we describe a family where multiple individuals developing cHL have inherited a reciprocal translocation between chromosomes 2 and 3. The translocation disrupts KLHDC8B, an uncharacterized gene from a region (3p21.31) previously implicated in lymphoma and related malignancies, resulting in its loss of expression. We tested KLHDC8B as a candidate gene for cHL and found that a 5'-UTR polymorphism responsible for decreasing its translational expression is associated with cHL in probands from other families with cHL and segregates with disease in those pedigrees. In one of three informative sporadic cases of cHL, we detected loss of heterozygosity (LOH) for KLHDC8B in RS cells, but not reactive T lymphocytes, purified from a malignant lymph node. KLHDC8B encodes a protein predicted to contain seven kelch repeat domains. KLHDC8B is expressed during mitosis, where it localizes to the midbody structure connecting cells about to separate during cytokinesis, and it is degraded after cell division. Depletion of KLHDC8B through RNA interference leads to an increase in binucleated cells, implicating its reduced expression in the formation of cHL's signature RS cell.
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91
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Abstract
Nrf2:INrf2 (Keap1) are cellular sensors of chemical- and radiation-induced oxidative and electrophilic stress. Nrf2 is a nuclear transcription factor that controls the expression and coordinated induction of a battery of defensive genes encoding detoxifying enzymes and antioxidant proteins. This is a mechanism of critical importance for cellular protection and cell survival. Nrf2 is retained in the cytoplasm by an inhibitor, INrf2 which functions as an adapter for Cul3/Rbx1-mediated degradation of Nrf2. In response to oxidative/electrophilic stress, Nrf2 is switched on and then off by distinct early and delayed mechanisms. Oxidative/electrophilic modification of INrf2 cysteine 151 and/or protein kinase C phosphorylation of Nrf2 serine 40 results in the escape or release of Nrf2 from INrf2. Nrf2 is stabilized and translocates to the nucleus, forms heterodimers with unknown proteins, and binds the antioxidant response element, which leads to coordinated activation of gene expression. It takes less than 15 min from the time of exposure to switch on nuclear import of Nrf2. This is followed by activation of a delayed mechanism that controls the switching off of Nrf2 activation of gene expression. GSK3beta phosphorylates Fyn at an unknown threonine residue(s), leading to the nuclear localization of Fyn. Fyn phosphorylates Nrf2 tyrosine 568, resulting in the nuclear export of Nrf2, binding with INrf2, and degradation of Nrf2. The switching on and off of Nrf2 protects cells against free radical damage, prevents apoptosis, and promotes cell survival.
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92
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Giles LM, Li L, Chin LS. Printor, a novel torsinA-interacting protein implicated in dystonia pathogenesis. J Biol Chem 2009; 284:21765-75. [PMID: 19535332 DOI: 10.1074/jbc.m109.004838] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Early onset generalized dystonia (DYT1) is an autosomal dominant neurological disorder caused by deletion of a single glutamate residue (torsinA DeltaE) in the C-terminal region of the AAA(+) (ATPases associated with a variety of cellular activities) protein torsinA. The pathogenic mechanism by which torsinA DeltaE mutation leads to dystonia remains unknown. Here we report the identification and characterization of a 628-amino acid novel protein, printor, that interacts with torsinA. Printor co-distributes with torsinA in multiple brain regions and co-localizes with torsinA in the endoplasmic reticulum. Interestingly, printor selectively binds to the ATP-free form but not to the ATP-bound form of torsinA, supporting a role for printor as a cofactor rather than a substrate of torsinA. The interaction of printor with torsinA is completely abolished by the dystonia-associated torsinA DeltaE mutation. Our findings suggest that printor is a new component of the DYT1 pathogenic pathway and provide a potential molecular target for therapeutic intervention in dystonia.
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Affiliation(s)
- Lisa M Giles
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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93
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Ectodermal-neural cortex 1 down-regulates Nrf2 at the translational level. PLoS One 2009; 4:e5492. [PMID: 19424503 PMCID: PMC2675063 DOI: 10.1371/journal.pone.0005492] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Accepted: 04/16/2009] [Indexed: 12/30/2022] Open
Abstract
The transcription factor Nrf2 is the master regulator of a cellular defense mechanism against environmental insults. The Nrf2-mediated antioxidant response is accomplished by the transcription of a battery of genes that encode phase II detoxifying enzymes, xenobiotic transporters, and antioxidants. Coordinated expression of these genes is critical in protecting cells from toxic and carcinogenic insults and in maintaining cellular redox homeostasis. Activation of the Nrf2 pathway is primarily controlled by Kelch-like ECH-associated protein 1 (Keap1), which is a molecular switch that turns on or off the Nrf2 signaling pathway according to intracellular redox conditions. Here we report our finding of a novel Nrf2 suppressor ectodermal-neural cortex 1 (ENC1), which is a BTB-Kelch protein and belongs to the same family as Keap1. Transient expression of ENC1 reduced steady-state levels of Nrf2 and its downstream gene expression. Although ENC1 interacted with Keap1 indirectly, the ENC1-mediated down-regulation of Nrf2 was independent of Keap1. The negative effect of ENC1 on Nrf2 was not due to a change in the stability of Nrf2 because neither proteasomal nor lysosomal inhibitors had any effects. Overexpression of ENC1 did not result in a change in the level of Nrf2 mRNA, rather, it caused a decrease in the rate of Nrf2 protein synthesis. These results demonstrate that ENC1 functions as a negative regulator of Nrf2 through suppressing Nrf2 protein translation, which adds another level of complexity in controlling the Nrf2 signaling pathway.
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94
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Suzuki Y, Noma A, Suzuki T, Ishitani R, Nureki O. Structural basis of tRNA modification with CO2 fixation and methylation by wybutosine synthesizing enzyme TYW4. Nucleic Acids Res 2009; 37:2910-25. [PMID: 19287006 PMCID: PMC2685095 DOI: 10.1093/nar/gkp158] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Wybutosine (yW), one of the most complicated modified nucleosides, is found in the anticodon loop of eukaryotic phenylalanine tRNA. This hypermodified nucleoside ensures correct codon recognition by stabilizing codon-anticodon pairings during the decoding process in the ribosome. TYW4 is an S-adenosylmethionine (SAM)-dependent enzyme that catalyzes the final step of yW biosynthesis, methylation and methoxycarbonylation. However, the structural basis for the catalytic mechanism by TYW4, and especially that for the methoxycarbonylation, have remained elusive. Here we report the apo and cofactor-bound crystal structures of yeast TYW4. The structures revealed that the C-terminal domain folds into a beta-propeller structure, forming part of the binding pocket for the target nucleoside. A comparison of the apo, SAM-bound, and S-adenosylhomocysteine-bound structures of TYW4 revealed a drastic structural change upon cofactor binding, which may sequester solvent from the catalytic site during the reaction and facilitate product release after the reaction. In conjunction with the functional analysis, our results suggest that TYW4 catalyzes both methylation and methoxycarbonylation at a single catalytic site, and in the latter reaction, the methoxycarbonyl group is formed through the fixation of carbon dioxide.
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Affiliation(s)
- Yoko Suzuki
- Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama-shi, Kanagawa, Japan
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95
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Abstract
Protein phosphorylation appears to be a universal mechanism of protein regulation. Genomics has provided the means to compile inventories of protein phosphatases across a wide selection of organisms and this has supplied insights into the evolution of this group of enzymes. Protein phosphatases evolved independently several times yielding the groups we observe today. Starting from a core catalytic domain, phosphatases evolved by a series of gene duplication events and by adopting the use of regulatory subunits and/or fusion with novel functional modules or domains. Recent analyses also suggest that the serine/threonine specific enzymes are more ancient than the PTPs (protein tyrosine phosphatases). It is likely that the latter played a key role at the onset of metazoan evolution in conjunction with the tremendous expansion of tyrosine kinases and PTPs at this point. In the present review, we discuss the evolution of the PTPs, the serine/threonine specific PPP (phosphoprotein phosphatase) and PPM (metallo-dependent protein phosphatase) families and the more recently discovered phosphatases that utilize an aspartate-based catalytic mechanism. We will also highlight examples of convergent evolution and several phosphatases which are unique to plants.
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96
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Laezza F, Wilding TJ, Sequeira S, Craig AM, Huettner JE. The BTB/kelch protein, KRIP6, modulates the interaction of PICK1 with GluR6 kainate receptors. Neuropharmacology 2008; 55:1131-9. [PMID: 18692513 PMCID: PMC2685165 DOI: 10.1016/j.neuropharm.2008.07.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 06/21/2008] [Accepted: 07/07/2008] [Indexed: 11/18/2022]
Abstract
Neuronal proteins of the BTB/kelch and PDZ domain families interact with different regions of the cytoplasmic C-terminal domain of the GluR6 kainate receptor subunit. The BTB/kelch protein KRIP6 binds within a 58 amino acid segment of GluR6 proximal to the plasma membrane. In contrast, PDZ domain proteins, such as PICK1 and PSD95, interact with the last 4 residues of the GluR6 C-terminus. KRIP6 reduces peak currents mediated by recombinant GluR6 receptors and by native kainate receptors in neurons, whereas PICK1 stabilizes kainate receptors at synapses. Thus, protein-protein interactions at the C-terminal domain of GluR6 are important for regulating kainate receptor physiology. Here, we show by co-clustering and co-immunoprecipitation that KRIP6 interacts with PICK1 in heterologous cells. In addition, we demonstrate a novel modulation of GluR6 receptors by PICK1 resulting in increased peak current and relative desensitization of GluR6-mediated currents, phenotypes opposite to those produced by KRIP6. Importantly, these effects cancel out when KRIP6 and PICK1 are co-expressed together with GluR6. KRIP6 and PICK1 strongly co-cluster and co-immunoprecipitate regardless of the presence of GluR6. Immunofluorescence analysis reveals that GluR6 can either join the KRIP6-PICK1 clusters or remain separate; however, co-expression of KRIP6 reduces the fraction of PICK1 that co-immunoprecipitates with GluR6. Taken together, these results indicate that, in addition to a previously demonstrated direct interaction with the GluR6 C-terminal domain, KRIP6 regulates kainate receptors by inhibiting PICK1 modulation via competition or a mutual blocking effect.
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Affiliation(s)
- Fernanda Laezza
- Department of Cell Biology and Physiology, Washington University, St Louis, MO 63110, USA.
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97
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Genini S, Delputte PL, Malinverni R, Cecere M, Stella A, Nauwynck HJ, Giuffra E. Genome-wide transcriptional response of primary alveolar macrophages following infection with porcine reproductive and respiratory syndrome virus. J Gen Virol 2008; 89:2550-2564. [PMID: 18796724 PMCID: PMC2885007 DOI: 10.1099/vir.0.2008/003244-0] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Porcine reproductive and respiratory syndrome is a major cause of economic loss for the swine industry worldwide. Porcine reproductive and respiratory syndrome virus (PRRSV) triggers weak and atypical innate immune responses, but key genes and mechanisms by which the virus interferes with the host innate immunity have not yet been elucidated. In this study, genes that control the response of the main target of PRRSV, porcine alveolar macrophages (PAMs), were profiled in vitro with a time-course experiment spanning the first round of virus replication. PAMs were obtained from six piglets and challenged with the Lelystad PRRSV strain, and gene expression was investigated using Affymetrix microarrays and real-time PCR. Of the 1409 differentially expressed transcripts identified by analysis of variance, two, five, 25, 16 and 100 differed from controls by a minimum of 1.5-fold at 1, 3, 6, 9 and 12 h post-infection (p.i.), respectively. A PRRSV infection effect was detectable between 3 and 6 h p.i., and was characterized by a consistent downregulation of gene expression, followed by the start of the host innate immune response at 9 h p.i. The expression of beta interferon 1 (IFN-β), but not of IFN-α, was strongly upregulated, whilst few genes commonly expressed in response to viral infections and/or induced by interferons were found to be differentially expressed. A predominance of anti-apoptotic transcripts (e.g. interleukin-10), a shift towards a T-helper cell type 2 response and a weak upregulation of tumour necrosis factor-α expression were observed within 12 h p.i., reinforcing the hypotheses that PRRSV has developed sophisticated mechanisms to escape the host defence.
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Affiliation(s)
- Sem Genini
- Parco Tecnologico Padano - CERSA, Via A. Einstein, 26900 Lodi, Italy
| | - Peter L Delputte
- Department of Virology, Parasitology, and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | | | - Maria Cecere
- Parco Tecnologico Padano - CERSA, Via A. Einstein, 26900 Lodi, Italy
| | - Alessandra Stella
- Parco Tecnologico Padano - CERSA, Via A. Einstein, 26900 Lodi, Italy
| | - Hans J Nauwynck
- Department of Virology, Parasitology, and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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98
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Phylogenetic, structural and functional relationships between WD- and Kelch-repeat proteins. Subcell Biochem 2008; 48:6-19. [PMID: 18925367 DOI: 10.1007/978-0-387-09595-0_2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The beta-propeller domain is a widespread protein organizational motif. Typically, beta-propeller proteins are encoded by repeated sequences where each repeat unit corresponds to a twisted beta-sheet structural motif; these beta-sheets are arranged in a circle around a central axis to generate the beta-propeller structure. Two superfamilies of beta-propeller proteins, the WD-repeat and Kelch-repeat families, exhibit similarities not only in structure, but, remarkably, also in the types of molecular functions they perform. While it is unlikely that WD and Kelch repeats evolved from a common ancestor, their evolution into diverse families of similar function may reflect the evolutionary advantages of the stable core beta-propeller fold. In this chapter, we examine the relationships between these two widespread protein families, emphasizing recently published work relating to the structure and function of both Kelch and WD-repeat proteins.
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99
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Valiyaveettil M, Bentley AA, Gursahaney P, Hussien R, Chakravarti R, Kureishy N, Prag S, Adams JC. Novel role of the muskelin-RanBP9 complex as a nucleocytoplasmic mediator of cell morphology regulation. J Cell Biol 2008; 182:727-39. [PMID: 18710924 PMCID: PMC2518711 DOI: 10.1083/jcb.200801133] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Accepted: 07/23/2008] [Indexed: 12/22/2022] Open
Abstract
The evolutionarily conserved kelch-repeat protein muskelin was identified as an intracellular mediator of cell spreading. We discovered that its morphological activity is controlled by association with RanBP9/RanBPM, a protein involved in transmembrane signaling and a conserved intracellular protein complex. By subcellular fractionation, endogenous muskelin is present in both the nucleus and the cytosol. Muskelin subcellular localization is coregulated by its C terminus, which provides a cytoplasmic restraint and also controls the interaction of muskelin with RanBP9, and its atypical lissencephaly-1 homology motif, which has a nuclear localization activity which is regulated by the status of the C terminus. Transient or stable short interfering RNA-based knockdown of muskelin resulted in protrusive cell morphologies with enlarged cell perimeters. Morphology was specifically restored by complementary DNAs encoding forms of muskelin with full activity of the C terminus for cytoplasmic localization and RanBP9 binding. Knockdown of RanBP9 resulted in equivalent morphological alterations. These novel findings identify a role for muskelin-RanBP9 complex in pathways that integrate cell morphology regulation and nucleocytoplasmic communication.
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Affiliation(s)
- Manojkumar Valiyaveettil
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
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100
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Krp1 (Sarcosin) promotes lateral fusion of myofibril assembly intermediates in cultured mouse cardiomyocytes. Exp Cell Res 2008; 314:1177-91. [PMID: 18178185 DOI: 10.1016/j.yexcr.2007.12.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 12/07/2007] [Accepted: 12/07/2007] [Indexed: 11/23/2022]
Abstract
Krp1, also called sarcosin, is a cardiac and skeletal muscle kelch repeat protein hypothesized to promote the assembly of myofibrils, the contractile organelles of striated muscles, through interaction with N-RAP and actin. To elucidate its role, endogenous Krp1 was studied in primary embryonic mouse cardiomyocytes. While immunofluorescence showed punctate Krp1 distribution throughout the cell, detergent extraction revealed a significant pool of Krp1 associated with cytoskeletal elements. Reduction of Krp1 expression with siRNA resulted in specific inhibition of myofibril accumulation with no effect on cell spreading. Immunostaining analysis and electron microscopy revealed that cardiomyocytes lacking Krp1 contained sarcomeric proteins with longitudinal periodicities similar to mature myofibrils, but fibrils remained thin and separated. These thin myofibrils were degraded by a scission mechanism distinct from the myofibril disassembly pathway observed during cell division in the developing heart. The data are consistent with a model in which Krp1 promotes lateral fusion of adjacent thin fibrils into mature, wide myofibrils and contribute insight into mechanisms of myofibrillogenesis and disassembly.
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