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Zhang J, Chen J, Wang L, Zhao S, Wang W, Li J, Liu B, Qi X, Zheng H, Lu M. An essential role for Arabidopsis Trs33 in cell growth and organization in plant apical meristems. Plant Cell Rep 2020; 39:381-391. [PMID: 31828377 DOI: 10.1007/s00299-019-02497-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 12/02/2019] [Indexed: 06/10/2023]
Abstract
Trafficking protein particle (TRAPP) complexes subunit gene AtTrs33 plays an important role in keeping apical meristematic activity and dominance in Arabidopsis. TRAPP complexes, composed of multimeric subunits, are guanine-nucleotide exchange factors for certain Rab GTPases and are believed to be involved in the regulation of membrane trafficking, but the cases in Arabidopsis are largely unknown. Trs33, recently proposed to be a component of TRAPP IV, is non-essential in yeast cells. A single copy of Trs33 gene, AtTrs33, was identified in Arabidopsis. GUS activity assay indicated that AtTrs33 was ubiquitously expressed. Based on a T-DNA insertion line, we found that loss-of-function of AtTrs33 is lethal for apical growth. Knock-down or knock-in of AtTrs33 affects apical meristematic growth and fertility, which indicates that AtTrs33 plays an important role in keeping apical meristematic activity and dominance in Arabidopsis. Analysis of auxin responses and PIN1/2 localization indicate that impaired apical meristematic activity and dominance were caused by altered auxin responses through non-polarized PIN1 localization. The present study reported that AtTrs33 plays an essential role in Arabidopsis cell growth and organization, which is different with its homologue in yeast. These findings provide new insights into the functional divergence of TRAPP subunits.
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Affiliation(s)
- Jin Zhang
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100 091, China
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Jun Chen
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100 091, China
- Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, QC, H3A 1B1, Canada
| | - Lijuan Wang
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100 091, China
| | - Shutang Zhao
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100 091, China
| | - Weina Wang
- Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, QC, H3A 1B1, Canada
| | - Jianbo Li
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100 091, China
| | - Bobin Liu
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100 091, China
| | - Xingyun Qi
- Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, QC, H3A 1B1, Canada
| | - Huanquan Zheng
- Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, QC, H3A 1B1, Canada.
| | - Mengzhu Lu
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100 091, China.
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hanzhou, Zhejiang, 311300, China.
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Sacher M, Shahrzad N, Kamel H, Milev MP. TRAPPopathies: An emerging set of disorders linked to variations in the genes encoding transport protein particle (TRAPP)-associated proteins. Traffic 2018; 20:5-26. [PMID: 30152084 DOI: 10.1111/tra.12615] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 08/23/2018] [Accepted: 08/26/2018] [Indexed: 02/06/2023]
Abstract
The movement of proteins between cellular compartments requires the orchestrated actions of many factors including Rab family GTPases, Soluble NSF Attachment protein REceptors (SNAREs) and so-called tethering factors. One such tethering factor is called TRAnsport Protein Particle (TRAPP), and in humans, TRAPP proteins are distributed into two related complexes called TRAPP II and III. Although thought to act as a single unit within the complex, in the past few years it has become evident that some TRAPP proteins function independently of the complex. Consistent with this, variations in the genes encoding these proteins result in a spectrum of human diseases with diverse, but partially overlapping, phenotypes. This contrasts with other tethering factors such as COG, where variations in the genes that encode its subunits all result in an identical phenotype. In this review, we present an up-to-date summary of all the known disease-related variations of genes encoding TRAPP-associated proteins and the disorders linked to these variations which we now call TRAPPopathies.
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Affiliation(s)
- Michael Sacher
- Department of Biology, Concordia University, Montreal, Quebec, Canada.,Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Nassim Shahrzad
- Department of Medicine, University of California, San Francisco, California
| | - Hiba Kamel
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Miroslav P Milev
- Department of Biology, Concordia University, Montreal, Quebec, Canada
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Liu CC, Ho PC, Lee IT, Chen YA, Chu CH, Teng CC, Wu SN, Sze CI, Chiang MF, Chang NS. WWOX Phosphorylation, Signaling, and Role in Neurodegeneration. Front Neurosci 2018; 12:563. [PMID: 30158849 PMCID: PMC6104168 DOI: 10.3389/fnins.2018.00563] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 07/26/2018] [Indexed: 12/21/2022] Open
Abstract
Homozygous null mutation of tumor suppressor WWOX/Wwox gene leads to severe neural diseases, metabolic disorders and early death in the newborns of humans, mice and rats. WWOX is frequently downregulated in the hippocampi of patients with Alzheimer’s disease (AD). In vitro analysis revealed that knockdown of WWOX protein in neuroblastoma cells results in aggregation of TRAPPC6AΔ, TIAF1, amyloid β, and Tau in a sequential manner. Indeed, TRAPPC6AΔ and TIAF1, but not tau and amyloid β, aggregates are present in the brains of healthy mid-aged individuals. It is reasonable to assume that very slow activation of a protein aggregation cascade starts sequentially with TRAPPC6AΔ and TIAF1 aggregation at mid-ages, then caspase activation and APP de-phosphorylation and degradation, and final accumulation of amyloid β and Tau aggregates in the brains at greater than 70 years old. WWOX binds Tau-hyperphosphorylating enzymes (e.g., GSK-3β) and blocks their functions, thereby supporting neuronal survival and differentiation. As a neuronal protective hormone, 17β-estradiol (E2) binds WWOX at an NSYK motif in the C-terminal SDR (short-chain alcohol dehydrogenase/reductase) domain. In this review, we discuss how WWOX and E2 block protein aggregation during neurodegeneration, and how a 31-amino-acid zinc finger-like Zfra peptide restores memory loss in mice.
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Affiliation(s)
- Chan-Chuan Liu
- Department of Cell Biology and Anatomy, National Cheng Kung University College of Medicine, Tainan, Taiwan.,Institute of Basic Medical Sciences, National Cheng Kung University College of Medicine, Tainan, Taiwan
| | - Pei-Chuan Ho
- Institute of Molecular Medicine, National Cheng Kung University College of Medicine, Tainan, Taiwan
| | - I-Ting Lee
- Institute of Molecular Medicine, National Cheng Kung University College of Medicine, Tainan, Taiwan
| | - Yu-An Chen
- Graduate Institute of Medical Genomics and Proteomics, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chun-Hsien Chu
- Institute of Molecular Medicine, National Cheng Kung University College of Medicine, Tainan, Taiwan
| | - Chih-Chuan Teng
- Department of Nursing, Chronic Diseases and Health Promotion Research Center, Chang Gung University of Science and Technology, Chiayi, Taiwan
| | - Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University College of Medicine, Tainan, Taiwan
| | - Chun-I Sze
- Department of Cell Biology and Anatomy, National Cheng Kung University College of Medicine, Tainan, Taiwan.,Institute of Basic Medical Sciences, National Cheng Kung University College of Medicine, Tainan, Taiwan
| | - Ming-Fu Chiang
- Department of Neurosurgery, Mackay Memorial Hospital, Mackay Medicine, Nursing and Management College, Graduate Institute of Injury Prevention and Control, Taipei Medical University, Taipei, Taiwan
| | - Nan-Shan Chang
- Institute of Basic Medical Sciences, National Cheng Kung University College of Medicine, Tainan, Taiwan.,Institute of Molecular Medicine, National Cheng Kung University College of Medicine, Tainan, Taiwan.,Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, New York, NY, United States.,Graduate Institute of Biomedical Sciences, College of Medicine, China Medical University, Taichung, Taiwan
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Marques DA, Jones FC, Di Palma F, Kingsley DM, Reimchen TE. Experimental evidence for rapid genomic adaptation to a new niche in an adaptive radiation. Nat Ecol Evol 2018; 2:1128-1138. [PMID: 29942074 PMCID: PMC6519129 DOI: 10.1038/s41559-018-0581-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 05/17/2018] [Indexed: 12/20/2022]
Abstract
A substantial part of biodiversity is thought to have arisen from adaptive radiations in which one lineage rapidly diversified into multiple lineages adapted to many different niches. However, selection and drift reduce genetic variation during adaptation to new niches and may thus prevent or slow down further niche shifts. We tested whether rapid adaptation is still possible from a highly derived ecotype in the adaptive radiation of threespine stickleback on the Haida Gwaii archipelago, Western Canada. In a 19-years selection experiment, we let giant stickleback from a large blackwater lake evolve in a small clearwater pond without vertebrate predators. 56 whole genomes from the experiment and 26 natural populations revealed that adaptive genomic change was rapid in many small genomic regions and encompassed 75% of the adaptive genomic change between 12,000 years old ecotypes. Adaptive genomic change was as fast as phenotypic change in defence and trophic morphology and both were largely parallel between the short-term selection experiment and long-term natural adaptive radiation. Our results show that functionally relevant standing genetic variation can persist in derived adaptive radiation members, allowing adaptive radiations to unfold very rapidly.
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Affiliation(s)
- David A Marques
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada. .,Aquatic Ecology & Evolution, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland. .,Department of Fish Ecology and Evolution, Eawag: Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland.
| | - Felicity C Jones
- Department of Developmental Biology, HHMI and Stanford University School of Medicine, Stanford, CA, USA.,Friedrich Miescher Laboratory of the Max Planck Society, Tübingen, Germany
| | - Federica Di Palma
- Earlham Institute, Norwich Research Park, Norwich, UK.,Department of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - David M Kingsley
- Department of Developmental Biology, HHMI and Stanford University School of Medicine, Stanford, CA, USA
| | - Thomas E Reimchen
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
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Mohamoud HS, Ahmed S, Jelani M, Alrayes N, Childs K, Vadgama N, Almramhi MM, Al-Aama JY, Goodbourn S, Nasir J. A missense mutation in TRAPPC6A leads to build-up of the protein, in patients with a neurodevelopmental syndrome and dysmorphic features. Sci Rep 2018; 8:2053. [PMID: 29391579 DOI: 10.1038/s41598-018-20658-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 01/19/2018] [Indexed: 11/24/2022] Open
Abstract
Childhood onset clinical syndromes involving intellectual disability and dysmorphic features, such as polydactyly, suggest common developmental pathways link seemingly unrelated phenotypes. We identified a consanguineous family of Saudi origin with varying complex features including intellectual disability, speech delay, facial dysmorphism and polydactyly. Combining, microarray based comparative genomic hybridisation (CGH) to identify regions of homozygosity, with exome sequencing, led to the identification of homozygous mutations in five candidate genes (RSPH6A, ANKK1, AMOTL1, ALKBH8, TRAPPC6A), all of which appear to be pathogenic as predicted by Proven, SIFT and PolyPhen2 and segregate perfectly with the disease phenotype. We therefore looked for differences in expression levels of each protein in HEK293 cells, expressing either the wild-type or mutant full-length cDNA construct. Unexpectedly, wild-type TRAPPC6A appeared to be unstable, but addition of the proteasome inhibitor MG132 stabilised its expression. Mutations have previously been reported in several members of the TRAPP complex of proteins, including TRAPPC2, TRAPPC9 and TRAPPC11, resulting in disorders involving skeletal abnormalities, intellectual disability, speech impairment and developmental delay. TRAPPC6A joins a growing list of proteins belonging to the TRAPP complex, implicated in clinical syndromes with neurodevelopmental abnormalities.
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Ramírez-Peinado S, Ignashkova TI, van Raam BJ, Baumann J, Sennott EL, Gendarme M, Lindemann RK, Starnbach MN, Reiling JH. TRAPPC13 modulates autophagy and the response to Golgi stress. J Cell Sci 2017; 130:2251-2265. [PMID: 28536105 DOI: 10.1242/jcs.199521] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 05/22/2017] [Indexed: 01/05/2023] Open
Abstract
Tether complexes play important roles in endocytic and exocytic trafficking of lipids and proteins. In yeast, the multisubunit transport protein particle (TRAPP) tether regulates endoplasmic reticulum (ER)-to-Golgi and intra-Golgi transport and is also implicated in autophagy. In addition, the TRAPP complex acts as a guanine nucleotide exchange factor (GEF) for Ypt1, which is homologous to human Rab1a and Rab1b. Here, we show that human TRAPPC13 and other TRAPP subunits are critically involved in the survival response to several Golgi-disrupting agents. Loss of TRAPPC13 partially preserves the secretory pathway and viability in response to brefeldin A, in a manner that is dependent on ARF1 and the large GEF GBF1, and concomitant with reduced caspase activation and ER stress marker induction. TRAPPC13 depletion reduces Rab1a and Rab1b activity, impairs autophagy and leads to increased infectivity to the pathogenic bacterium Shigella flexneri in response to brefeldin A. Thus, our results lend support for the existence of a mammalian TRAPPIII complex containing TRAPPC13, which is important for autophagic flux under certain stress conditions.
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Affiliation(s)
- Silvia Ramírez-Peinado
- Metabolism and Signaling in Cancer, BioMed X Innovation Center, Im Neuenheimer Feld 583, Heidelberg 69120, Germany
| | - Tatiana I Ignashkova
- Metabolism and Signaling in Cancer, BioMed X Innovation Center, Im Neuenheimer Feld 583, Heidelberg 69120, Germany
| | - Bram J van Raam
- Metabolism and Signaling in Cancer, BioMed X Innovation Center, Im Neuenheimer Feld 583, Heidelberg 69120, Germany
| | - Jan Baumann
- Metabolism and Signaling in Cancer, BioMed X Innovation Center, Im Neuenheimer Feld 583, Heidelberg 69120, Germany
| | - Erica L Sennott
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Mathieu Gendarme
- Metabolism and Signaling in Cancer, BioMed X Innovation Center, Im Neuenheimer Feld 583, Heidelberg 69120, Germany
| | - Ralph K Lindemann
- Merck Serono TA Oncology, Merck KGaA, Frankfurter Str. 250, Darmstadt D-64293, Germany
| | - Michael N Starnbach
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Jan H Reiling
- Metabolism and Signaling in Cancer, BioMed X Innovation Center, Im Neuenheimer Feld 583, Heidelberg 69120, Germany
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7
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Bourgeois YXC, Delahaie B, Gautier M, Lhuillier E, Malé PJG, Bertrand JAM, Cornuault J, Wakamatsu K, Bouchez O, Mould C, Bruxaux J, Holota H, Milá B, Thébaud C. A novel locus on chromosome 1 underlies the evolution of a melanic plumage polymorphism in a wild songbird. R Soc Open Sci 2017; 4:160805. [PMID: 28386436 PMCID: PMC5367300 DOI: 10.1098/rsos.160805] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 01/12/2017] [Indexed: 06/07/2023]
Abstract
Understanding the mechanisms responsible for phenotypic diversification within and among species ultimately rests with linking naturally occurring mutations to functionally and ecologically significant traits. Colour polymorphisms are of great interest in this context because discrete colour patterns within a population are often controlled by just a few genes in a common environment. We investigated how and why phenotypic diversity arose and persists in the Zosterops borbonicus white-eye of Reunion (Mascarene archipelago), a colour polymorphic songbird in which all highland populations contain individuals belonging to either a brown or a grey plumage morph. Using extensive phenotypic and genomic data, we demonstrate that this melanin-based colour polymorphism is controlled by a single locus on chromosome 1 with two large-effect alleles, which was not previously described as affecting hair or feather colour. Differences between colour morphs appear to rely upon complex cis-regulatory variation that either prevents the synthesis of pheomelanin in grey feathers, or increases its production in brown ones. We used coalescent analyses to show that, from a 'brown' ancestral population, the dominant 'grey' allele spread quickly once it arose from a new mutation. Since colour morphs are always found in mixture, this implies that the selected allele does not go to fixation, but instead reaches an intermediate frequency, as would be expected under balancing selection.
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Affiliation(s)
- Yann X. C. Bourgeois
- Laboratoire Évolution et Diversité Biologique, UMR5174 CNRS, Université Paul Sabatier – ENFA, 31062 Toulouse Cedex 9, France
| | - Boris Delahaie
- Laboratoire Évolution et Diversité Biologique, UMR5174 CNRS, Université Paul Sabatier – ENFA, 31062 Toulouse Cedex 9, France
| | - Mathieu Gautier
- INRA, UMR 1062 CBGP (INRA, IRD, Cirad, Montpellier SupAgro), Campus de Baillarguet, 34988 Montferrier-sur-Lez, France
| | - Emeline Lhuillier
- INRA, GeT-PlaGe, Genotoul, 24 chemin de Borde Rouge, Auzeville, CS 52627, 31326 Castanet-Tolosan, France
- INRA, UAR1209, 24 chemin de Borde Rouge, Auzeville, CS 52627, 31326 Castanet-Tolosan, France
| | - Pierre-Jean G. Malé
- Laboratoire Évolution et Diversité Biologique, UMR5174 CNRS, Université Paul Sabatier – ENFA, 31062 Toulouse Cedex 9, France
| | - Joris A. M. Bertrand
- Laboratoire Évolution et Diversité Biologique, UMR5174 CNRS, Université Paul Sabatier – ENFA, 31062 Toulouse Cedex 9, France
| | - Josselin Cornuault
- Laboratoire Évolution et Diversité Biologique, UMR5174 CNRS, Université Paul Sabatier – ENFA, 31062 Toulouse Cedex 9, France
| | - Kazumasa Wakamatsu
- Department of Chemistry, Fujita Health University, School of Health Sciences, Toyoake Aichi 470-1192, Japan
| | - Olivier Bouchez
- INRA, GeT-PlaGe, Genotoul, 24 chemin de Borde Rouge, Auzeville, CS 52627, 31326 Castanet-Tolosan, France
- GenPhySE, Université de Toulouse, INRA, INPT, INP-ENVT, 24 chemin de Borde Rouge, Auzeville, CS 52627, 31326 Castanet-Tolosan, France
| | - Claire Mould
- Laboratoire Évolution et Diversité Biologique, UMR5174 CNRS, Université Paul Sabatier – ENFA, 31062 Toulouse Cedex 9, France
| | - Jade Bruxaux
- Laboratoire Évolution et Diversité Biologique, UMR5174 CNRS, Université Paul Sabatier – ENFA, 31062 Toulouse Cedex 9, France
| | - Hélène Holota
- Laboratoire Évolution et Diversité Biologique, UMR5174 CNRS, Université Paul Sabatier – ENFA, 31062 Toulouse Cedex 9, France
| | - Borja Milá
- National Museum of Natural Sciences, Spanish National Research Council (CSIC), 28006 Madrid, Spain
| | - Christophe Thébaud
- Laboratoire Évolution et Diversité Biologique, UMR5174 CNRS, Université Paul Sabatier – ENFA, 31062 Toulouse Cedex 9, France
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Zhu P, Liang L, Shao X, Luo W, Jiang S, Zhao Q, Sun N, Zhao Y, Li J, Wang J, Zhou Y, Zhang J, Wang G, Jiang L, Chen H, Li C. Host Cellular Protein TRAPPC6AΔ Interacts with Influenza A Virus M2 Protein and Regulates Viral Propagation by Modulating M2 Trafficking. J Virol 2017; 91:e01757-16. [PMID: 27795429 DOI: 10.1128/JVI.01757-16] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 09/30/2016] [Indexed: 12/30/2022] Open
Abstract
Influenza A virus (IAV) matrix protein 2 (M2) plays multiple roles in the early and late phases of viral infection. Once synthesized, M2 is translocated to the endoplasmic reticulum (ER), travels to the Golgi apparatus, and is sorted at the trans-Golgi network (TGN) for transport to the apical plasma membrane, where it functions in virus budding. We hypothesized that M2 trafficking along with its secretory pathway must be finely regulated, and host factors could be involved in this process. However, no studies examining the role of host factors in M2 posttranslational transport have been reported. Here, we used a yeast two-hybrid (Y2H) system to screen for host proteins that interact with the M2 protein and identified transport protein particle complex 6A (TRAPPC6A) as a potential binding partner. We found that both TRAPPC6A and its N-terminal internal-deletion isoform, TRAPPC6A delta (TRAPPC6AΔ), interact with M2. Truncation and mutation analyses showed that the highly conserved leucine residue at position 96 of M2 is critical for mediating this interaction. The role of TRAPPC6AΔ in the viral life cycle was investigated by the knockdown of endogenous TRAPPC6AΔ with small interfering RNA (siRNA) and by generating a recombinant virus that was unable to interact with TRAPPC6A/TRAPPC6AΔ. The results indicated that TRAPPC6AΔ, through its interaction with M2, slows M2 trafficking to the apical plasma membrane, favors viral replication in vitro, and positively modulates virus virulence in mice. IMPORTANCE The influenza A virus M2 protein regulates the trafficking of not only other proteins but also itself along the secretory pathway. However, the host factors involved in the regulation of the posttranslational transport of M2 are largely unknown. In this study, we identified TRAPPC6A and its N-terminal internal-deletion isoform, TRAPPC6AΔ, as interacting partners of M2. We found that the leucine (L) residue at position 96 of M2 is critical for mediating this interaction, which leads us to propose that the high level of conservation of 96L is a consequence of M2 adaptation to its interacting host factor TRAPPC6A/TRAPPC6AΔ. Importantly, we discovered that TRAPPC6AΔ can positively regulate viral replication in vitro by modulating M2 trafficking to the plasma membrane.
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Aso Y, Nakamura K, Kimura N, Takemaru M, Arakawa R, Fujiki M, Hirano T, Kumamoto T, Matsubara E. Induction of Genes Expressed in Endothelial Cells of the Corpus Callosum in the Chronic Cerebral Hypoperfusion Rat Model. Pathobiology 2016; 84:25-37. [PMID: 27458816 DOI: 10.1159/000446876] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/17/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Cerebrovascular white matter lesions (WMLs) are associated with cognitive impairment in patients with subcortical vascular dementia. We performed a comprehensive gene expression analysis to elucidate genes associated with WML development in a chronic cerebral hypoperfusion rat model. METHODS Brains of rats with bilateral carotid ligation (2VO, n = 10) and sham-operated rats (n = 5-10/group) were removed on days 1, 7, or 28 after surgery. Total RNA isolated from the corpus callosum was evaluated by microarray analysis and quantitative reverse transcription-polymerase chain reaction. RESULTS On days 7 and 28, WMLs exhibited histologic changes. On day 7, 16 genes were differentially expressed between groups. mRNA levels of Ptprb, Kcnj8, Crispld2, Bcl6b, and Gja5 were differentially expressed in 2VO rats on day 7, but then returned to normal, whereas mRNA levels of Vwf and Trappc6a were upregulated after day 7. Immunohistochemistry showed that GJA5 and vWF were detected in endothelial cells, KCNJ8 in endothelial cells and astrocytes, CRISPLD2 in neurons and astrocytes, and TRAPPC6A in neurons. CONCLUSION Our findings indicate novel genes that may be associated with WML development in the chronic cerebral hypoperfusion rat model, and suggest an important role of neurovascular dysfunction in the pathophysiology.
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Affiliation(s)
- Yasuhiro Aso
- Department of Neurology, Faculty of Medicine, Oita University, Oita, Japan
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Chang JY, Lee MH, Lin SR, Yang LY, Sun HS, Sze CI, Hong Q, Lin YS, Chou YT, Hsu LJ, Jan MS, Gong CX, Chang NS. Trafficking protein particle complex 6A delta (TRAPPC6AΔ) is an extracellular plaque-forming protein in the brain. Oncotarget 2016; 6:3578-89. [PMID: 25650666 PMCID: PMC4414138 DOI: 10.18632/oncotarget.2876] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 12/08/2014] [Indexed: 11/25/2022] Open
Abstract
Tumor suppressor WWOX is involved in the progression of cancer and neurodegeneration. Here, we examined whether protein aggregation occurs in the brain of nondemented, middle-aged humans and whether this is associated with WWOX downregulation. We isolated an N-terminal internal deletion isoform, TPC6AΔ, derived from alternative splicing of the TRAPPC6A (TPC6A) gene transcript. TPC6AΔ proteins are present as aggregates or plaques in the extracellular matrix of the brain such as in the cortex. Filter retardation assays revealed that aggregate formation of TPC6AΔ occurs preceding Aβ generation in the hippocampi of middle-aged postmortem normal humans. In a Wwox gene knockout mouse model, we showed the plaques of pT181-Tau and TPC6AΔ in the cortex and hippocampus in 3-week-old mice, suggesting a role of WWOX in limiting TPC6AΔ aggregation. To support this hypothesis, in vitro analysis revealed that TGF-β1 induces dissociation of the ectopic complex of TPC6AΔ and WWOX in cells, and then TPC6AΔ undergoes Ser35 phosphorylation-dependent polymerization and induces caspase 3 activation and Aβ production. Similarly, knockdown of WWOX by siRNA resulted in dramatic aggregation of TPC6AΔ. Together, when WWOX is downregulated, TPC6AΔ is phosphorylated at Ser35 and becomes aggregated for causing caspase activation that leads to Tau aggregation and Aβ formation.
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Affiliation(s)
- Jean-Yun Chang
- Institute of Molecular Medicine, National Cheng Kung University Medical College, Tainan, Taiwan, ROC
| | - Ming-Hui Lee
- Institute of Molecular Medicine, National Cheng Kung University Medical College, Tainan, Taiwan, ROC
| | - Sing-Ru Lin
- Institute of Molecular Medicine, National Cheng Kung University Medical College, Tainan, Taiwan, ROC
| | - Li-Yi Yang
- Institute of Molecular Medicine, National Cheng Kung University Medical College, Tainan, Taiwan, ROC
| | - H Sunny Sun
- Institute of Molecular Medicine, National Cheng Kung University Medical College, Tainan, Taiwan, ROC
| | - Chun-I Sze
- Departments of Anatomy and Cell Biology, National Cheng Kung University Medical College, Tainan, Taiwan, ROC
| | - Qunying Hong
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, ROC
| | - Yee-Shin Lin
- Department of Microbiology and Immunology, National Cheng Kung University Medical College, Tainan, Taiwan, ROC.,Center for Infectious Disease and Signaling Research, National Cheng Kung University Medical College, Tainan, Taiwan, ROC
| | - Ying-Tsen Chou
- Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan, Taiwan, ROC
| | - Li-Jin Hsu
- Department of Microbiology and Immunology, National Cheng Kung University Medical College, Tainan, Taiwan, ROC.,Center for Infectious Disease and Signaling Research, National Cheng Kung University Medical College, Tainan, Taiwan, ROC.,Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University Medical College, Tainan, Taiwan, ROC
| | - Ming-Shiou Jan
- Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Cheng-Xin Gong
- Institute of Microbiology and Immunology, Chung Shan Medical University, Taichung, Taiwan, ROC
| | - Nan-Shan Chang
- Institute of Molecular Medicine, National Cheng Kung University Medical College, Tainan, Taiwan, ROC.,Center for Infectious Disease and Signaling Research, National Cheng Kung University Medical College, Tainan, Taiwan, ROC.,Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan, Taiwan, ROC.,Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, Taiwan, ROC.,Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
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11
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Chang JY, Chang NS. WWOX dysfunction induces sequential aggregation of TRAPPC6AΔ, TIAF1, tau and amyloid β, and causes apoptosis. Cell Death Discov 2015; 1:15003. [PMID: 27551439 DOI: 10.1038/cddiscovery.2015.3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 06/05/2015] [Indexed: 12/21/2022] Open
Abstract
Aggregated vesicle-trafficking protein isoform TRAPPC6AΔ (TPC6AΔ) has a critical role in causing caspase activation, tau aggregation and Aβ generation in the brains of nondemented middle-aged humans, patients with Alzheimer’s disease (AD) and 3-week-old Wwox gene knockout mice. WWOX blocks neurodegeneration via interactions with tau and tau-phosphorylating enzymes. WWOX deficiency leads to epilepsy, mental retardation and early death. Here, we demonstrated that TGF-β1 induces shuttling of endogenous wild-type TPC6A and TPC6AΔ in between nucleoli and mitochondria (~40–60 min per round trip), and WWOX reduces the shuttling time by 50%. TGF-β1 initially maximizes the binding of TPC6AΔ to the C-terminal tail of WWOX, followed by dissociation. TPC6AΔ then undergoes aggregation, together with TIAF1 (TGF-β1-induced antiapoptotic factor), in the mitochondria to induce apoptosis. An additional rescue scenario is that TGF-β1 induces Tyr33 phosphorylation and unfolding of WWOX and its the N-terminal WW domain slowly binds TPC6AΔ to block aggregation and apoptosis. Similarly, loss of WWOX induces TPC6AΔ polymerization first, then aggregation of TIAF1, amyloid β and tau, and subsequent cell death, suggesting that a cascade of protein aggregation leads to neurodegeneration.
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12
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Abstract
Membrane trafficking depends on transport vesicles and carriers docking and fusing with the target organelle for the delivery of cargo. Membrane tethers and small guanosine triphosphatases (GTPases) mediate the docking of transport vesicles/carriers to enhance the efficiency of the subsequent SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor)-mediated fusion event with the target membrane bilayer. Different classes of membrane tethers and their specific intracellular location throughout the endomembrane system are now well defined. Recent biochemical and structural studies have led to a deeper understanding of the mechanism by which membrane tethers mediate docking of membrane carriers as well as an appreciation of the role of tethers in coordinating the correct SNARE complex and in regulating the organization of membrane compartments. This review will summarize the properties and roles of membrane tethers of both secretory and endocytic systems.
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Affiliation(s)
- Pei Zhi Cheryl Chia
- National Institute of Dental and Craniofacial Research, National Institutes of Health30 Convent Drive, Bethesda, MD 20892-4340USA
| | - Paul A. Gleeson
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute30 Flemington Road, The University of Melbourne, Victoria 3010Australia
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13
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Hudson NJ, Baker ML, Hart NS, Wynne JW, Gu Q, Huang Z, Zhang G, Ingham AB, Wang L, Reverter A. Sensory rewiring in an echolocator: genome-wide modification of retinogenic and auditory genes in the bat Myotis davidii. G3 (Bethesda) 2014; 4:1825-35. [PMID: 25096539 DOI: 10.1534/g3.114.011262] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Bats comprise 20% of all mammalian species and display a number of characteristics, including true flight, echolocation, and a heightened ability to resist viral load that uniquely position this group for comparative genomic studies. Here we searched for evidence of genomic variation consistent with sensory rewiring through bat evolution. We focused on two species with divergent sensory preferences. Myotis davidii is a bat species that echolocates and possesses dim- but not daylight-adapted vision whereas the black flying fox (Pteropus alecto) has highly developed day vision but does not echolocate. Using the naked mole rat as a reference, we found five functional genes (CYP1A2, RBP3, GUCY2F, CRYBB1, and GRK7) encoding visual proteins that have degenerated into pseudogenes in M. davidii but not P. alecto. In a second approach genome-wide codon usage bias (CUB) was compared between the two bat species. This CUB ranking systematically enriched for vision-related (CLN8, RD3, IKZF1, LAMC3, CRX, SOX8, VAX2, HPS1, RHO, PRPH2, and SOX9) and hearing-related (TPRN, TMIE, SLC52A3, OTOF, WFS1, SOD1, TBX18, MAP1A, OTOS, GPX1, and USH1G) machinery in M. davidii but not P. alecto. All vision and hearing genes selectively enriched in M. davidii for which orthologs could be identified also were more biased in the echolocating M. lucifugus than the nonecholocating P. vampyrus. We suggest that the existence of codon bias in vision- and hearing-related genes in a species that has evolved echolocation implies CUB is part of evolution’s toolkit to rewire sensory systems. We propose that the two genetic changes (pseudogene formation and CUB) collectively paint a picture of that incorporates a combination of destruction and gain-of-function. Together, they help explain how natural selection has reduced physiological costs associated with the development of a smaller eye poorly adapted to day vision but that also contribute to enhanced dim light vision and the hearing adaptations consonant with echolocation.
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14
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Brunet S, Sacher M. In Sickness and in Health: The Role of TRAPP and Associated Proteins in Disease. Traffic 2014; 15:803-18. [PMID: 24917561 DOI: 10.1111/tra.12183] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 06/06/2014] [Accepted: 06/06/2014] [Indexed: 12/12/2022]
Affiliation(s)
- Stephanie Brunet
- Department of Biology; Concordia University; 7141 Sherbrooke Street West, SP-457.01 Montreal QC H4B 1R6 Canada
| | - Michael Sacher
- Department of Biology; Concordia University; 7141 Sherbrooke Street West, SP-457.01 Montreal QC H4B 1R6 Canada
- Department of Anatomy and Cell Biology; McGill University; 845 Sherbrooke Street West Montreal QC H3A 0G4 Canada
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15
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Abstract
Vertebrate pigment cells in the eye and skin are useful models for cell types that use specialized endosomal trafficking pathways to partition cargo proteins to unique lysosome-related organelles such as melanosomes. This review describes current models of protein trafficking required for melanosome biogenesis in mammalian melanocytes.
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Affiliation(s)
- Anand Sitaram
- Cell and Molecular Biology Graduate Group, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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16
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Ishida M, Ohbayashi N, Maruta Y, Ebata Y, Fukuda M. Functional involvement of Rab1A in microtubule-dependent anterograde melanosome transport in melanocytes. J Cell Sci 2012; 125:5177-87. [PMID: 22854043 DOI: 10.1242/jcs.109314] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Melanosomes are transported to the cell periphery of melanocytes by coordination between bidirectional microtubule-dependent movements and unidirectional actin-dependent movement. Although both the mechanism of the actin-dependent melanosome transport and the mechanism of the microtubule-dependent retrograde melanosome transport in mammalian skin melanocytes have already been determined, almost nothing is known about the mechanism of the microtubule-dependent anterograde melanosome transport. Small GTPase Rab proteins are common regulators of membrane traffic in all eukaryotes, and in this study we performed genome-wide screening for Rab proteins that are involved in anterograde melanosome transport by expressing 60 different constitutive active (and negative) mutants, and succeeded in identifying Rab1A, originally described as a Golgi-resident Rab, as a prime candidate. Endogenous Rab1A protein was found to be localized to mature melanosomes in melanocytes, and its functional ablation either by siRNA-mediated knockdown or by overexpression of a cytosolic form of Rab1A-GTPase-activating protein/TBC1D20 induced perinuclear melanosome aggregation. The results of time-lapse imaging further revealed that long-range anterograde melanosome movements were specifically suppressed in Rab1A-deficient melanocytes, whereas retrograde melanosome transport occurred normally. Taken together, these findings indicate that Rab1A is the first crucial component of the anterograde melanosome transport machinery to be identified in mammalian skin melanocytes.
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Affiliation(s)
- Morié Ishida
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan
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17
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Yu S, Liang Y. A trapper keeper for TRAPP, its structures and functions. Cell Mol Life Sci 2012; 69:3933-44. [PMID: 22669257 DOI: 10.1007/s00018-012-1024-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 04/20/2012] [Accepted: 05/02/2012] [Indexed: 12/22/2022]
Abstract
During biosynthesis many membrane and secreted proteins are transported from the endoplasmic reticulum, through the Golgi and on to the plasma membrane in small transport vesicles. These transport vesicles have to undergo budding, movement, tethering, docking, and fusion at each organelle of the biosynthetic pathway. The transport protein particle (TRAPP) complex was initially identified as the tethering factor for endoplasmic reticulum (ER)-derived COPII vesicles, but the functions of TRAPP may extend to other areas of biology. Three forms of TRAPP complexes have been discovered to date, and recent advances in research have provided new insights on the structures and functions of TRAPP. Here we provide a comprehensive review of the recent findings in TRAPP biology.
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Barrowman J, Bhandari D, Reinisch K, Ferro-Novick S. TRAPP complexes in membrane traffic: convergence through a common Rab. Nat Rev Mol Cell Biol 2010; 11:759-63. [PMID: 20966969 DOI: 10.1038/nrm2999] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Transport protein particle (TRAPP; also known as trafficking protein particle), a multimeric guanine nucleotide-exchange factor for the yeast GTPase Ypt1 and its mammalian homologue, RAB1, regulates multiple membrane trafficking pathways. TRAPP complexes exist in three forms, each of which activates Ypt1 or RAB1 through a common core of subunits and regulates complex localization through distinct subunits. Whereas TRAPPI and TRAPPII tether coated vesicles during endoplasmic reticulum to Golgi and intra-Golgi traffic, respectively, TRAPPIII has recently been shown to be required for autophagy. These advances illustrate how the TRAPP complexes link Ypt1 and RAB1 activation to distinct membrane-tethering events.
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Xu X, Kedlaya R, Higuchi H, Ikeda S, Justice MJ, Setaluri V, Ikeda A. Mutation in archain 1, a subunit of COPI coatomer complex, causes diluted coat color and Purkinje cell degeneration. PLoS Genet 2010; 6:e1000956. [PMID: 20502676 PMCID: PMC2873907 DOI: 10.1371/journal.pgen.1000956] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Accepted: 04/19/2010] [Indexed: 11/18/2022] Open
Abstract
Intracellular trafficking is critical for delivering molecules and organelles to their proper destinations to carry out normal cellular functions. Disruption of intracellular trafficking has been implicated in the pathogenesis of various neurodegenerative disorders. In addition, a number of genes involved in vesicle/organelle trafficking are also essential for pigmentation, and loss of those genes is often associated with mouse coat-color dilution and human hypopigmentary disorders. Hence, we postulated that screening for mouse mutants with both neurological defects and coat-color dilution will help identify additional factors associated with intracellular trafficking in neuronal cells. In this study, we characterized a mouse mutant with a unique N-ethyl-N-nitrosourea (ENU)-induced mutation, named nur17. nur17 mutant mice exhibit both coat-color dilution and ataxia due to Purkinje cell degeneration in the cerebellum. By positional cloning, we identified that the nur17 mouse carries a T-to-C missense mutation in archain 1 (Arcn1) gene which encodes the delta subunit of the coat protein I (COPI) complex required for intracellular trafficking. Consistent with this function, we found that intracellular trafficking is disrupted in nur17 melanocytes. Moreover, the nur17 mutation leads to common characteristics of neurodegenerative disorders such as abnormal protein accumulation, ER stress, and neurofibrillary tangles. Our study documents for the first time the physiological consequences of the impairment of the ARCN1 function in the whole animal and demonstrates a direct association between ARCN1 and neurodegeneration.
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Affiliation(s)
- Xinjie Xu
- Department of Medical Genetics, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Rajendra Kedlaya
- Department of Dermatology, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Hitoshi Higuchi
- Department of Medical Genetics, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Sakae Ikeda
- Department of Medical Genetics, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Monica J. Justice
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Vijayasaradhi Setaluri
- Department of Dermatology, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Akihiro Ikeda
- Department of Medical Genetics, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
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20
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Choi M, Chan C, Chan D, Luk K, Cheah K, Tanner J. Biochemical consequences of sedlin mutations that cause spondyloepiphyseal dysplasia tarda. Biochem J 2009; 423:233-42. [DOI: 10.1042/bj20090541] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
SEDT (spondyloepiphyseal dysplasia tarda) is a late-onset X-linked recessive skeletal dysplasia caused by mutations in the gene SEDL coding for sedlin. In the present paper, we investigated four missense mutations observed in SEDT and compare biochemical and cellular characteristics relative to the wild-type protein to address the mechanism of disease and to gain insight into the function of the sedlin protein. In situ hybridization and immunohistochemical experiments in mouse growth plates revealed sedlin to be predominantly expressed in proliferating and hypertrophic chondrocytes. Cell culture studies showed that the wild-type protein localized predominantly in the vicinity of the nucleus and the Golgi, with further localization around the cytoplasm, whereas mutation resulted in mislocalization. The D47Y mutant was expressed similarly to the wild-type, but the S73L, F83S and V130D mutants showed particularly low levels of expression that were rescued in the presence of the proteasome inhibitor MG132 (benzyloxycarbonyl-leucylleucylleucinal). Furthermore, whereas the D47Y mutant folded similarly and had similar stability to the wild-type sedlin as shown by CD and fluorescence, the S73L, F83S and V130D mutants all misfolded during expression. Two independent assays showed that the D47Y mutation resulted in an increased affinity for the transport protein particle component Bet3 compared with the wild-type sedlin. Our results suggest that the sedlin mutations S73L, F83S and V130D cause SEDT by sedlin misfolding, whereas the D47Y mutation may influence normal TRAPP (transport protein particle) dynamics.
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21
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Abstract
TRAPP is a multi-subunit complex that acts as a Ypt/Rab activator at the Golgi apparatus. TRAPP exists in two forms: TRAPP I is comprised of five essential and conserved subunits and TRAPP II contains two additional essential and conserved subunits, Trs120 and Trs130. Previously, we have shown that Trs65, a nonessential fungi-specific TRAPP subunit, plays a role in TRAPP II assembly. TRS33 encodes another nonessential but conserved TRAPP subunit whose function is not known. Here, we show that one of these two subunits, nonessential individually, is required for TRAPP II assembly. Trs33 and Trs65 share sequence, intracellular localization and interaction similarities. Specifically, Trs33 interacts genetically with both Trs120 and Trs130 and physically with Trs120. In addition, trs33 mutant cells contain lower levels of TRAPP II and exhibit aberrant localization of the Golgi Ypts. Together, our results indicate that in yeast, TRAPP II assembly is an essential process that can be accomplished by either of two related TRAPP subunits. Moreover, because humans express two Trs33 homologues, we propose that the requirement of Trs33 for TRAPP II assembly is conserved from yeast to humans.
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Affiliation(s)
- Andrei A Tokarev
- Department of Biological Sciences, Laboratory for Molecular Biology, University of Illinois at Chicago, Molecular Biology Research Building, 900 South Ashland Avenue Chicago, IL 60607, USA
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Kümmel D, Oeckinghaus A, Wang C, Krappmann D, Heinemann U. Distinct isocomplexes of the TRAPP trafficking factor coexist inside human cells. FEBS Lett 2008; 582:3729-33. [DOI: 10.1016/j.febslet.2008.09.056] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 09/15/2008] [Accepted: 09/25/2008] [Indexed: 11/22/2022]
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23
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Abstract
Vesicle‐mediated transport is a process carried out by virtually every cell and is required for the proper targeting and secretion of proteins. As such, there are numerous players involved to ensure that the proteins are properly localized. Overall, transport requires vesicle budding, recognition of the vesicle by the target membrane and fusion of the vesicle with the target membrane resulting in delivery of its contents. The initial interaction between the vesicle and the target membrane has been referred to as tethering. Because this is the first contact between the two membranes, tethering is critical to ensuring that specificity is achieved. It is therefore not surprising that there are numerous ‘tethering factors’ involved ranging from multisubunit complexes, coiled‐coil proteins and Rab guanosine triphosphatases. Of the multisubunit tethering complexes, one of the best studied at the molecular level is the evolutionarily conserved TRAPP complex. There are two forms of this complex: TRAPP I and TRAPP II. In yeast, these complexes function in a number of processes including endoplasmic reticulum‐to‐Golgi transport (TRAPP I) and an ill‐defined step at the trans Golgi (TRAPP II). Because the complex was first reported in 1998 (1), there has been a decade of studies that have clarified some aspects of its function but have also raised further questions. In this review, we will discuss recent advances in our understanding of yeast and mammalian TRAPP at the structural and functional levels and its role in disease while trying to resolve some apparent discrepancies and highlighting areas for future study.
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Affiliation(s)
- Michael Sacher
- Department of Biology, Concordia University, Montreal, QC, Canada.
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