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Wang M, Wu N, Wang H, Liu C, Chen Q, Xu T, Chen Y, Zhao Y, Ma Z. Overproduction of mycotoxin biosynthetic enzymes triggers Fusarium toxisome-shaped structure formation via endoplasmic reticulum remodeling. PLoS Pathog 2024; 20:e1011913. [PMID: 38166144 PMCID: PMC10786393 DOI: 10.1371/journal.ppat.1011913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 01/12/2024] [Accepted: 12/19/2023] [Indexed: 01/04/2024] Open
Abstract
Mycotoxin deoxynivalenol (DON) produced by the Fusarium graminearum complex is highly toxic to animal and human health. During DON synthesis, the endoplasmic reticulum (ER) of F. graminearum is intensively reorganized, from thin reticular structure to thickened spherical and crescent structure, which was referred to as "DON toxisome". However, the underlying mechanism of how the ER is reorganized into toxisome remains unknown. In this study, we discovered that overproduction of ER-localized DON biosynthetic enzyme Tri4 or Tri1, or intrinsic ER-resident membrane proteins FgHmr1 and FgCnx was sufficient to induce toxisome-shaped structure (TSS) formation under non-toxin-inducing conditions. Moreover, heterologous overexpression of Tri1 and Tri4 proteins in non-DON-producing fungi F. oxysporum f. sp. lycopersici and F. fujikuroi also led to TSS formation. In addition, we found that the high osmolarity glycerol (HOG), but not the unfolded protein response (UPR) signaling pathway was involved in the assembly of ER into TSS. By using toxisome as a biomarker, we screened and identified a novel chemical which exhibited high inhibitory activity against toxisome formation and DON biosynthesis, and inhibited Fusarium growth species-specifically. Taken together, this study demonstrated that the essence of ER remodeling into toxisome structure is a response to the overproduction of ER-localized DON biosynthetic enzymes, providing a novel pathway for management of mycotoxin contamination.
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Affiliation(s)
- Minhui Wang
- State Key Laboratory of Rice Biology, Key Laboratory of Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, People’s Republic of China
| | - Ningjie Wu
- Zhejiang Research Institute of Chemical Industry, Hangzhou, People’s Republic of China
| | - Huiyuan Wang
- State Key Laboratory of Rice Biology, Key Laboratory of Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, People’s Republic of China
| | - Chang Liu
- State Key Laboratory of Rice Biology, Key Laboratory of Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, People’s Republic of China
| | - Qiaowan Chen
- State Key Laboratory of Rice Biology, Key Laboratory of Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, People’s Republic of China
| | - Tianming Xu
- Zhejiang Research Institute of Chemical Industry, Hangzhou, People’s Republic of China
| | - Yun Chen
- State Key Laboratory of Rice Biology, Key Laboratory of Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, People’s Republic of China
| | - Youfu Zhao
- Irrigated Agriculture Research and Extension Center, Department of Plant Pathology, Washington State University, Prosser, Washington, United States of America
| | - Zhonghua Ma
- State Key Laboratory of Rice Biology, Key Laboratory of Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, People’s Republic of China
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2
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Aboufares El Alaoui A, Buhl E, Galizia S, Hodge JJL, de Vivo L, Bellesi M. Increased interaction between endoplasmic reticulum and mitochondria following sleep deprivation. BMC Biol 2023; 21:1. [PMID: 36600217 PMCID: PMC9814192 DOI: 10.1186/s12915-022-01498-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 12/07/2022] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Prolonged cellular activity may overload cell function, leading to high rates of protein synthesis and accumulation of misfolded or unassembled proteins, which cause endoplasmic reticulum (ER) stress and activate the unfolded protein response (UPR) to re-establish normal protein homeostasis. Previous molecular work has demonstrated that sleep deprivation (SD) leads to ER stress in neurons, with a number of ER-specific proteins being upregulated to maintain optimal cellular proteostasis. It is still not clear which cellular processes activated by sleep deprivation lead to ER- stress, but increased cellular metabolism, higher request for protein synthesis, and over production of oxygen radicals have been proposed as potential contributing factors. Here, we investigate the transcriptional and ultrastructural ER and mitochondrial modifications induced by sleep loss. RESULTS We used gene expression analysis in mouse forebrains to show that SD was associated with significant transcriptional modifications of genes involved in ER stress but also in ER-mitochondria interaction, calcium homeostasis, and mitochondrial respiratory activity. Using electron microscopy, we also showed that SD was associated with a general increase in the density of ER cisternae in pyramidal neurons of the motor cortex. Moreover, ER cisternae established new contact sites with mitochondria, the so-called mitochondria associated membranes (MAMs), important hubs for molecule shuttling, such as calcium and lipids, and for the modulation of ATP production and redox state. Finally, we demonstrated that Drosophila male mutant flies (elav > linker), in which the number of MAMs had been genetically increased, showed a reduction in the amount and consolidation of sleep without alterations in the homeostatic sleep response to SD. CONCLUSIONS We provide evidence that sleep loss induces ER stress characterized by increased crosstalk between ER and mitochondria. MAMs formation associated with SD could represent a key phenomenon for the modulation of multiple cellular processes that ensure appropriate responses to increased cell metabolism. In addition, MAMs establishment may play a role in the regulation of sleep under baseline conditions.
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Affiliation(s)
- Amina Aboufares El Alaoui
- grid.7010.60000 0001 1017 3210Department of Experimental and Clinical Medicine, Marche Polytechnic University, Ancona, Italy ,grid.5602.10000 0000 9745 6549School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Edgar Buhl
- grid.5337.20000 0004 1936 7603School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Sabrina Galizia
- grid.5337.20000 0004 1936 7603School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - James J. L. Hodge
- grid.5337.20000 0004 1936 7603School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Luisa de Vivo
- grid.5337.20000 0004 1936 7603School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK ,grid.5602.10000 0000 9745 6549School of Pharmacy, University of Camerino, Camerino, Italy
| | - Michele Bellesi
- grid.5602.10000 0000 9745 6549School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy ,grid.5337.20000 0004 1936 7603School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
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3
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Endoplasmic Reticulum Stress Underlies Nanosilver-Induced Neurotoxicity in Immature Rat Brain. Int J Mol Sci 2022; 23:ijms232113013. [PMID: 36361797 PMCID: PMC9655133 DOI: 10.3390/ijms232113013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 10/23/2022] [Accepted: 10/24/2022] [Indexed: 12/03/2022] Open
Abstract
The growing production of silver nanoparticles (AgNPs), and their widespread use in medical and consumer products, poses a potential threat to the environment and raises questions about biosafety. Immature organisms are particularly susceptible to various insults during development. The biological characteristics of immature organisms are different from those of adults, and dictate the consequences of exposure to various toxic substances, including AgNPs. Nanoparticles are highly reactive and can easily cross the blood–brain barrier (BBB) to accumulate in brain tissues. It is therefore important to investigate the molecular mechanisms of AgNP-induced neurotoxicity in the developing brain. Immature 2-week-old rats were exposed to a low dose of AgNPs (0.2 mg/kg b.w.) over a long period. Subsequently, brain tissues of the animals were subjected to ultrastructural and molecular analyses to determine endoplasmic reticulum (ER) stress. Ultrastructural markers of ER stress, such as pathological alterations in the ER and elongated forms of mitochondria accompanied by autophagy structures, were confirmed to be present in AgNP-exposed rat brain. Evidence for induction of ER stress in neurons was also provided by molecular markers. Upregulation of genes related to the ER-stress-induced unfolded protein response (UPR) pathway, such as GRP78, PERK, and CHOP ATF-6, was observed at the transcriptional and translational levels. The results show that prolonged exposure of immature rats to a low dose of AgNPs during the developmental period leads to induction of ER stress in the neurons of the developing brain. Simultaneously, in response to AgNP-induced ER stress, neurons promote protective mechanisms that partially compensate for ER stress by regulating the biodynamic processes of mitochondria and autophagy.
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4
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Pittari D, Dalla Torre M, Borini E, Hummel B, Sawarkar R, Semino C, van Anken E, Panina-Bordignon P, Sitia R, Anelli T. CREB3L1 and CREB3L2 control Golgi remodelling during decidualization of endometrial stromal cells. Front Cell Dev Biol 2022; 10:986997. [PMID: 36313580 PMCID: PMC9608648 DOI: 10.3389/fcell.2022.986997] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Upon progesterone stimulation, Endometrial Stromal Cells (EnSCs) undergo a differentiation program into secretory cells (decidualization) to release in abundance factors crucial for embryo implantation. We previously demonstrated that decidualization requires massive reshaping of the secretory pathway and, in particular, of the Golgi complex. To decipher the underlying mechanisms, we performed a time-course transcriptomic analysis of in vitro decidualizing EnSC. Pathway analysis shows that Gene Ontology terms associated with vesicular trafficking and early secretory pathway compartments are the most represented among those enriched for upregulated genes. Among these, we identified a cluster of co-regulated genes that share CREB3L1 and CREB3L2 binding elements in their promoter regions. Indeed, both CREB3L1 and CREB3L2 transcription factors are up-regulated during decidualization. Simultaneous downregulation of CREB3L1 and CREB3L2 impairs Golgi enlargement, and causes dramatic changes in decidualizing EnSC, including Golgi fragmentation, collagen accumulation in dilated Endoplasmic Reticulum cisternae, and overall decreased protein secretion. Thus, both CREB3L1 and CREB3L2 are required for Golgi reshaping and efficient protein secretion, and, as such, for successful decidualization.
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Affiliation(s)
- Daniele Pittari
- Faculty of Medicine, Vita-Salute San Raffaele University, Milan, Italy
| | - Marco Dalla Torre
- Faculty of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Elena Borini
- Faculty of Medicine, Vita-Salute San Raffaele University, Milan, Italy
| | - Barbara Hummel
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Ritwick Sawarkar
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
- Medical Research Council (MRC), University of Cambridge, Cambridge, United Kingdom
| | - Claudia Semino
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Eelco van Anken
- Faculty of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Paola Panina-Bordignon
- Faculty of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Neuroscience, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Roberto Sitia
- Faculty of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Tiziana Anelli
- Faculty of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
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5
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Tirincsi A, Sicking M, Hadzibeganovic D, Haßdenteufel S, Lang S. The Molecular Biodiversity of Protein Targeting and Protein Transport Related to the Endoplasmic Reticulum. Int J Mol Sci 2021; 23:143. [PMID: 35008565 PMCID: PMC8745461 DOI: 10.3390/ijms23010143] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/19/2021] [Accepted: 12/20/2021] [Indexed: 12/15/2022] Open
Abstract
Looking at the variety of the thousands of different polypeptides that have been focused on in the research on the endoplasmic reticulum from the last five decades taught us one humble lesson: no one size fits all. Cells use an impressive array of components to enable the safe transport of protein cargo from the cytosolic ribosomes to the endoplasmic reticulum. Safety during the transit is warranted by the interplay of cytosolic chaperones, membrane receptors, and protein translocases that together form functional networks and serve as protein targeting and translocation routes. While two targeting routes to the endoplasmic reticulum, SRP (signal recognition particle) and GET (guided entry of tail-anchored proteins), prefer targeting determinants at the N- and C-terminus of the cargo polypeptide, respectively, the recently discovered SND (SRP-independent) route seems to preferentially cater for cargos with non-generic targeting signals that are less hydrophobic or more distant from the termini. With an emphasis on targeting routes and protein translocases, we will discuss those functional networks that drive efficient protein topogenesis and shed light on their redundant and dynamic nature in health and disease.
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Affiliation(s)
- Andrea Tirincsi
- Department of Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany; (A.T.); (M.S.); (D.H.)
| | - Mark Sicking
- Department of Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany; (A.T.); (M.S.); (D.H.)
| | - Drazena Hadzibeganovic
- Department of Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany; (A.T.); (M.S.); (D.H.)
| | - Sarah Haßdenteufel
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sven Lang
- Department of Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg, Germany; (A.T.); (M.S.); (D.H.)
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6
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Anelli T, Dalla Torre M, Borini E, Mangini E, Ulisse A, Semino C, Sitia R, Panina-Bordignon P. Profound architectural and functional readjustments of the secretory pathway in decidualization of endometrial stromal cells. Traffic 2021; 23:4-20. [PMID: 34651407 DOI: 10.1111/tra.12822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 07/10/2021] [Accepted: 10/07/2021] [Indexed: 12/19/2022]
Abstract
Certain cell types must expand their exocytic pathway to guarantee efficiency and fidelity of protein secretion. A spectacular case is offered by decidualizing human endometrial stromal cells (EnSCs). In the midluteal phase of the menstrual cycle, progesterone stimulation induces proliferating EnSCs to differentiate into professional secretors releasing proteins essential for efficient blastocyst implantation. Here, we describe the architectural rearrangements of the secretory pathway of a human EnSC line (TERT-immortalized human endometrial stromal cells (T-HESC)). As in primary cells, decidualization entails proliferation arrest and the coordinated expansion of the entire secretory pathway without detectable activation of unfolded protein response (UPR) pathways. Decidualization proceeds also in the absence of ascorbic acid, an essential cofactor for collagen biogenesis, despite also the secretion of some proteins whose folding does not depend on vitamin C is impaired. However, even in these conditions, no overt UPR induction can be detected. Morphometric analyses reveal that the exocytic pathway does not increase relatively to the volume of the cell. Thus, differently from other cell types, abundant production is guaranteed by a coordinated increase of the cell size following arrest of proliferation.
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Affiliation(s)
- Tiziana Anelli
- Faculty of Medicine, San Raffaele Vita-Salute University, Milan, Italy.,Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Marco Dalla Torre
- Faculty of Medicine, San Raffaele Vita-Salute University, Milan, Italy
| | - Elena Borini
- Faculty of Medicine, San Raffaele Vita-Salute University, Milan, Italy
| | - Elisabetta Mangini
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Adele Ulisse
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Claudia Semino
- Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Roberto Sitia
- Faculty of Medicine, San Raffaele Vita-Salute University, Milan, Italy.,Division of Genetics and Cell Biology, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Paola Panina-Bordignon
- Faculty of Medicine, San Raffaele Vita-Salute University, Milan, Italy.,Division of Neuroscience, IRCCS Ospedale San Raffaele, Milan, Italy
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7
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Pick T, Beck A, Gamayun I, Schwarz Y, Schirra C, Jung M, Krause E, Niemeyer BA, Zimmermann R, Lang S, Anken EV, Cavalié A. Remodelling of Ca 2+ homeostasis is linked to enlarged endoplasmic reticulum in secretory cells. Cell Calcium 2021; 99:102473. [PMID: 34560367 DOI: 10.1016/j.ceca.2021.102473] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 08/27/2021] [Accepted: 09/08/2021] [Indexed: 11/30/2022]
Abstract
The endoplasmic reticulum (ER) is extensively remodelled during the development of professional secretory cells to cope with high protein production. Since ER is the principal Ca2+ store in the cell, we characterised the Ca2+ homeostasis in NALM-6 and RPMI 8226 cells, which are commonly used as human pre-B and antibody secreting plasma cell models, respectively. Expression levels of Sec61 translocons and the corresponding Sec61-mediated Ca2+ leak from ER, Ca2+ storage capacity and store-operated Ca2+ entry were significantly enlarged in the secretory RPMI 8226 cell line. Using an immunoglobulin M heavy chain producing HeLa cell model, we found that the enlarged Ca2+ storage capacity and Ca2+ leak from ER are linked to ER expansion. Our data delineates a developmental remodelling of Ca2+ homeostasis in professional secretory cells in which a high Sec61-mediated Ca2+ leak and, thus, a high Ca2+ turnover in the ER is backed up by enhanced store-operated Ca2+ entry.
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Affiliation(s)
- Tillman Pick
- Experimental and Clinical Pharmacology and Toxicology, Pre-clinical Center for Molecular Signalling (PZMS), Saarland University, 66421 Homburg, Germany.
| | - Andreas Beck
- Experimental and Clinical Pharmacology and Toxicology, Pre-clinical Center for Molecular Signalling (PZMS), Saarland University, 66421 Homburg, Germany
| | - Igor Gamayun
- Experimental and Clinical Pharmacology and Toxicology, Pre-clinical Center for Molecular Signalling (PZMS), Saarland University, 66421 Homburg, Germany
| | - Yvonne Schwarz
- Molecular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, 66421 Homburg, Germany
| | - Claudia Schirra
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, 66421 Homburg, Germany
| | - Martin Jung
- Medical Biochemistry and Molecular Biology, Pre-clinical Centre for Molecular Signalling (PZMS), Saarland University, 66421 Homburg, Germany
| | - Elmar Krause
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, 66421 Homburg, Germany
| | - Barbara A Niemeyer
- Molecular Biophysics, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, 66421 Homburg, Germany
| | - Richard Zimmermann
- Medical Biochemistry and Molecular Biology, Pre-clinical Centre for Molecular Signalling (PZMS), Saarland University, 66421 Homburg, Germany
| | - Sven Lang
- Medical Biochemistry and Molecular Biology, Pre-clinical Centre for Molecular Signalling (PZMS), Saarland University, 66421 Homburg, Germany
| | - Eelco van Anken
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute and Università Vita-Salute San Raffaele, Milan, Italy
| | - Adolfo Cavalié
- Experimental and Clinical Pharmacology and Toxicology, Pre-clinical Center for Molecular Signalling (PZMS), Saarland University, 66421 Homburg, Germany.
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8
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Chen HK, Rosset SL, Wang LH, Chen CS. The characteristics of host lipid body biogenesis during coral-dinoflagellate endosymbiosis. PeerJ 2021; 9:e11652. [PMID: 34221732 PMCID: PMC8234918 DOI: 10.7717/peerj.11652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 05/31/2021] [Indexed: 11/25/2022] Open
Abstract
Intracellular lipid body (LB) biogenesis depends on the symbiosis between coral hosts and their Symbiodinaceae. Therefore, understanding the mechanism(s) behind LB biosynthesis in corals can portentially elucide the drivers of cellular regulation during endosymbiosis. This study assessed LB formation in the gastrodermal tissue layer of the hermatypic coral Euphyllia glabrescens. Diel rhythmicity in LB size and distribution was observed; solar irradiation onset at sunrise initiated an increase in LB formation, which continued throughout the day and peaked after sunset at 18:00. The LBs migrated from the area near the mesoglea to the gastrodermal cell border near the coelenteron. Micro-LB biogenesis occurred in the endoplasmic reticulum (ER) of the host gastrodermal cells. A transcriptomic analysis of genes related to lipogenesis indicated that binding immunoglobulin protein (BiP) plays a key role in metabolic signaling pathways. The diel rhythmicity of LB biogenesis was correlated with ER-localized BiP expression. BiP expression peaked during the period with the largest increase in LB formation, thereby indicating that the chaperoning reaction of abnormal protein folding inside the host ER is likely involved in LB biosynthesis. These findings suggest that the host ER, central to LB formation, potentially facilitates the regulation of endosymbiosis between coral hosts and Symbiodiniaceae.
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Affiliation(s)
- Hung-Kai Chen
- National Museum of Marine Biology and Aquarium, Pingtung, Taiwan
| | - Sabrina L Rosset
- National Museum of Marine Biology and Aquarium, Pingtung, Taiwan
| | - Li-Hsueh Wang
- National Museum of Marine Biology and Aquarium, Pingtung, Taiwan.,Graduate Institute of Marine Biology, National Dong-Hwa University, Pingtung, Taiwan
| | - Chii-Shiarng Chen
- National Museum of Marine Biology and Aquarium, Pingtung, Taiwan.,Graduate Institute of Marine Biology, National Dong-Hwa University, Pingtung, Taiwan.,Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, Taiwan
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9
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Brown AI, Koslover EF. Design principles for the glycoprotein quality control pathway. PLoS Comput Biol 2021; 17:e1008654. [PMID: 33524026 PMCID: PMC7877790 DOI: 10.1371/journal.pcbi.1008654] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 02/11/2021] [Accepted: 12/21/2020] [Indexed: 01/11/2023] Open
Abstract
Newly-translated glycoproteins in the endoplasmic reticulum (ER) often undergo cycles of chaperone binding and release in order to assist in folding. Quality control is required to distinguish between proteins that have completed native folding, those that have yet to fold, and those that have misfolded. Using quantitative modeling, we explore how the design of the quality-control pathway modulates its efficiency. Our results show that an energy-consuming cyclic quality-control process, similar to the observed physiological system, outperforms alternative designs. The kinetic parameters that optimize the performance of this system drastically change with protein production levels, while remaining relatively insensitive to the protein folding rate. Adjusting only the degradation rate, while fixing other parameters, allows the pathway to adapt across a range of protein production levels, aligning with in vivo measurements that implicate the release of degradation-associated enzymes as a rapid-response system for perturbations in protein homeostasis. The quantitative models developed here elucidate design principles for effective glycoprotein quality control in the ER, improving our mechanistic understanding of a system crucial to maintaining cellular health. We explore the architecture and limitations of the quality-control pathway responsible for efficient folding of secretory proteins. Newly-synthesized proteins are tagged by the attachment of a ‘glycan’ sugar chain which facilitates their binding to a chaperone that assists protein folding. Removal of a specific sugar group on the glycan ends the interaction with the chaperone, and not-yet-folded proteins can be re-tagged for another round of chaperone binding. A degradation pathway acts in parallel with the folding cycle, to remove those proteins that have remained unfolded for a sufficiently long time. We develop and solve a mathematical model of this quality-control system, showing that the cyclical design found in living cells is uniquely able to maximize folded protein throughput while avoiding accumulation of unfolded proteins. Although this physiological model provides the best performance, its parameters must be adjusted to perform optimally under different protein production loads, and any single fixed set of parameters leads to poor performance when production rate is altered. We find that a single adjustable parameter, the protein degradation rate, is sufficient to allow optimal performance across a range of conditions. Interestingly, observations of living cells suggest that the degradation speed is indeed rapidly adjusted.
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Affiliation(s)
- Aidan I. Brown
- Department of Physics, University of California, San Diego, San Diego, California, United States of America
| | - Elena F. Koslover
- Department of Physics, University of California, San Diego, San Diego, California, United States of America
- * E-mail:
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10
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Aw R, De Wachter C, Laukens B, De Rycke R, De Bruyne M, Bell D, Callewaert N, Polizzi KM. Knockout of RSN1, TVP18 or CSC1-2 causes perturbation of Golgi cisternae in Pichia pastoris. Traffic 2020; 22:48-63. [PMID: 33263222 DOI: 10.1111/tra.12773] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 11/25/2020] [Accepted: 11/30/2020] [Indexed: 11/29/2022]
Abstract
The structural organization of the Golgi stacks in mammalian cells is intrinsically linked to function, including glycosylation, but the role of morphology is less clear in lower eukaryotes. Here we investigated the link between the structural organization of the Golgi and secretory pathway function using Pichia pastoris as a model system. To unstack the Golgi cisternae, we disrupted 18 genes encoding proteins in the secretory pathway without loss of viability. Using biosensors, confocal microscopy and transmission electron microscopy we identified three strains with irreversible perturbations in the stacking of the Golgi cisternae, all of which had disruption in genes that encode proteins with annotated function as or homology to calcium/calcium permeable ion channels. Despite this, no variation in the secretory pathway for ER size, whole cell glycomics or recombinant protein glycans was observed. Our investigations showed the robust nature of the secretory pathway in P. pastoris and suggest that Ca2+ concentration, homeostasis or signalling may play a significant role for Golgi stacking in this organism and should be investigated in other organisms.
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Affiliation(s)
- Rochelle Aw
- Department of Chemical Engineering, Imperial College London, London, UK.,Imperial College Centre for Synthetic Biology, Imperial College London, London, United Kingdom
| | - Charlot De Wachter
- VIB-UGent, Center for Medical Biotechnology, Ghent, Belgium.,Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Bram Laukens
- VIB-UGent, Center for Medical Biotechnology, Ghent, Belgium.,Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Riet De Rycke
- Department of Biomedical Molecular Biology and Expertise Centre for Transmission Electron Microscopy, Ghent University, Ghent, Belgium.,VIB Center for Inflammation Research and BioImaging Core, Ghent, Belgium
| | - Michiel De Bruyne
- Department of Biomedical Molecular Biology and Expertise Centre for Transmission Electron Microscopy, Ghent University, Ghent, Belgium.,VIB Center for Inflammation Research and BioImaging Core, Ghent, Belgium
| | - David Bell
- Section for Structural Biology, Department of Medicine, Imperial College London, London, United Kingdom.,London Biofoundry, Imperial College London, London, United Kingdom
| | - Nico Callewaert
- VIB-UGent, Center for Medical Biotechnology, Ghent, Belgium.,Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Karen M Polizzi
- Department of Chemical Engineering, Imperial College London, London, UK.,Imperial College Centre for Synthetic Biology, Imperial College London, London, United Kingdom
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11
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Nomura Y, Sylvester CF, Nguyen LO, Kandeel M, Hirata Y, Mungrue IN, Oh-Hashi K. Characterization of the 5'-flanking region of the human and mouse CHAC1 genes. Biochem Biophys Rep 2020; 24:100834. [PMID: 33102815 PMCID: PMC7573368 DOI: 10.1016/j.bbrep.2020.100834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 10/09/2020] [Indexed: 11/29/2022] Open
Abstract
The Unfolded Protein Response pathway is a conserved signaling mechanism having important roles in cellular physiology and is perturbed accompanying disease. We previously identified the novel UPR target gene CHAC1, a direct target of ATF4, downstream of PERK-EIF2A and activated by the UPR pathway. CHAC1 enzyme directs catalysis of γ-linked glutamate bonds within specific molecular targets. CHAC1 is the first enzyme characterized that can catalyze intracellular glutathione degradation in eukaryotes, having implications for regulation of oxidative stress. DDIT3 (CHOP) is a terminal UPR transcription factor, regulated by ATF4 and an output promoting cell death signaling. Herein we examine the relationship of CHOP controlling CHAC1 transcription in humans and mice. We note parallel induction of CHOP and CHAC1 in human cells after agonist induced UPR. Expanding upon previous reports, we define transcriptional induction of CHAC1 in humans and mice driven by ATF4 through a synergistic relationship with conserved ATF/CRE and CARE DNA sequences of the CHAC1 promoter. Using this system, we also tested effects of CHOP on CHAC1 transcription, and binding at the CHAC1 ATF/CRE using IM-EMSA. These data indicate a novel inhibitory effect of CHOP on CHAC1 transcription, which was ablated in the absence of the ATF/CRE control element. While direct binding of ATF4 to CHAC1 promoter sequences was confirmed, binding of CHOP to the CHAC1 ATF/CRE was not evident at baseline or after UPR induction. These data reveal CHAC1 as a novel CHOP inhibited target gene, acting through an upstream ATF/CRE motif via an indirect mechanism.
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Affiliation(s)
- Yuki Nomura
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
| | - Charity F Sylvester
- Department of Pharmacology and Experimental Therapeutics, LSU Health Sciences Center, 1901, Perdido St, New Orleans, LA, USA
| | - Lisa O Nguyen
- Department of Pharmacology and Experimental Therapeutics, LSU Health Sciences Center, 1901, Perdido St, New Orleans, LA, USA
| | - Mahmoud Kandeel
- Department of Physiology, Biochemistry and Pharmacology, Faculty of Veterinary Medicine, King Faisal University, Hofuf, Alahsa, 31982, Saudi Arabia.,Department of Pharmacology, Faculty of Veterinary Medicine, Kafrelsheikh University, Kafrelsheikh, Egypt
| | - Yoko Hirata
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.,Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
| | - Imran N Mungrue
- Department of Pharmacology and Experimental Therapeutics, LSU Health Sciences Center, 1901, Perdido St, New Orleans, LA, USA
| | - Kentaro Oh-Hashi
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.,Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
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12
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Mouton SN, Thaller DJ, Crane MM, Rempel IL, Terpstra OT, Steen A, Kaeberlein M, Lusk CP, Boersma AJ, Veenhoff LM. A physicochemical perspective of aging from single-cell analysis of pH, macromolecular and organellar crowding in yeast. eLife 2020; 9:e54707. [PMID: 32990592 PMCID: PMC7556870 DOI: 10.7554/elife.54707] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 09/28/2020] [Indexed: 01/03/2023] Open
Abstract
Cellular aging is a multifactorial process that is characterized by a decline in homeostatic capacity, best described at the molecular level. Physicochemical properties such as pH and macromolecular crowding are essential to all molecular processes in cells and require maintenance. Whether a drift in physicochemical properties contributes to the overall decline of homeostasis in aging is not known. Here, we show that the cytosol of yeast cells acidifies modestly in early aging and sharply after senescence. Using a macromolecular crowding sensor optimized for long-term FRET measurements, we show that crowding is rather stable and that the stability of crowding is a stronger predictor for lifespan than the absolute crowding levels. Additionally, in aged cells, we observe drastic changes in organellar volume, leading to crowding on the micrometer scale, which we term organellar crowding. Our measurements provide an initial framework of physicochemical parameters of replicatively aged yeast cells.
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Affiliation(s)
- Sara N Mouton
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center GroningenGroningenNetherlands
| | - David J Thaller
- Department of Cell Biology, Yale School of MedicineNew HavenUnited States
| | - Matthew M Crane
- Department of Pathology, School of Medicine, University of WashingtonSeattleUnited States
| | - Irina L Rempel
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center GroningenGroningenNetherlands
| | - Owen T Terpstra
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center GroningenGroningenNetherlands
| | - Anton Steen
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center GroningenGroningenNetherlands
| | - Matt Kaeberlein
- Department of Pathology, School of Medicine, University of WashingtonSeattleUnited States
| | - C Patrick Lusk
- Department of Cell Biology, Yale School of MedicineNew HavenUnited States
| | | | - Liesbeth M Veenhoff
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center GroningenGroningenNetherlands
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13
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Yamanaka T, Nishiyama R, Shimogori T, Nukina N. Proteomics-Based Approach Identifies Altered ER Domain Properties by ALS-Linked VAPB Mutation. Sci Rep 2020; 10:7610. [PMID: 32376919 PMCID: PMC7203144 DOI: 10.1038/s41598-020-64517-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Accepted: 04/17/2020] [Indexed: 12/13/2022] Open
Abstract
An ER transmembrane protein, vesicle-associated membrane protein-associated protein B (VAPB), binds to several organelle-resident membrane proteins to mediate ER-organelle tethering. Mutation in amyotrophic lateral sclerosis (ALS) induces protein misfolding and aggregation, leading to ER disorganization. Gain or loss of function is suggested for VAPB mutation, however comprehensive study focusing on VAPB-ER domain has yet been performed. We here conducted proteomic characterization of the ER containing VAPB and its ALS-linked P56S mutant. For this purpose, we first optimized the proteomics of different ER domains immuno-isolated from cultured cells, and identified ER sheet- and tubule-specific proteomes. By using these as references, we found that VAPB-ER proteome had intermediate ER domain properties but its tubular property was specifically decreased by its mutation. Biochemical, immunofluorescence and proximity ligation assays suggested this was mediated by delocalization of VAPB from ER tubules. The VAPB-ER proteomics further suggested reduced incorporation of multiple proteins located in different organelles, which was confirmed by proximity ligation assay. Taken together, our proteomics-based approach indicates altered ER domain properties and impaired ER-organelle tethering by VAPB mutation.
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Affiliation(s)
- Tomoyuki Yamanaka
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, Kyoto, Japan.
| | - Risa Nishiyama
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, Kyoto, Japan
| | - Tomomi Shimogori
- Molecular Mechanisms of Brain Development, RIKEN Center for Brain Science, Saitama, 351-0198, Japan
| | - Nobuyuki Nukina
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, Kyoto, Japan.
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14
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Nicotine exposure potentiates lung tumorigenesis by perturbing cellular surveillance. Br J Cancer 2020; 122:904-911. [PMID: 32001831 PMCID: PMC7078213 DOI: 10.1038/s41416-020-0730-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 01/08/2020] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Nicotine is a major tobacco component and found at circulating concentrations in smokers' bloodstreams. Although considered a non-carcinogenic substance, nicotine rapidly defuses to tissues after being inhaled, inviting effects on cellular physiology, particularly in the lung. Widespread increased use of nicotine-based e-cigarettes, especially in younger adults, creates an urgent need for improved understanding of nicotine's potential to impact human health. METHODS Biological and biochemistry methods were used to interrogate the potential for nicotine to weaken the genetic integrity of murine and human-lung epithelial cells. RESULTS We demonstrate that nicotine potentiates the growth of the lung epithelial cells in a dose-response fashion. Nicotine elicits an acute increase in reactive oxygen species (ROS), which persists at moderately high levels throughout the duration of nicotine exposure. The aberrant increases in ROS appear to induce ER stress and UPR activation, as reflected by BIP upregulation and PERK phosphorylation. Furthermore, prolonged nicotine exposure interferes with p53 function triggered by sodium arsenite. Unless p53 is suppressed, persistent nicotine exposure does not induce colony formation by lung epithelial cells in soft agar. CONCLUSION The data suggest that nicotine treatment, by perturbing intracellular redox state and altering p53 function, can create a pro-tumorigenic environment in lung epithelium. The results suggest caution in using nicotine replacement therapies and e-cigarettes.
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15
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Dong C, Tu W, He M, Fu J, Kobayashi A, Konishi T, Shao C. Role of Endoplasmic Reticulum and Mitochondrion in Proton Microbeam Radiation-Induced Bystander Effect. Radiat Res 2019; 193:63-72. [PMID: 31714866 DOI: 10.1667/rr15469.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
It is well known that mitochondria and the endoplasmic reticulum (ER) play important roles in radiation response, but their functions in radiation-induced bystander effect (RIBE) are largely unclear. In this study, we found that when a small portion of cells in a population of human lung fibroblast MRC-5 cells were precisely irradiated through either the nuclei or cytoplasm with counted microbeam protons, the yield of micronuclei (MN) and the levels of intracellular reactive oxygen species (ROS) in nonirradiated cells neighboring irradiated cells were significantly increased. Mito/ER-tracker staining demonstrated that the mitochondria were clearly activated after nuclear irradiation and ER mass approached a higher level after cytoplasmic irradiation. Moreover, the radiation-induced ROS was diminished by rotenone, an inhibitor of mitochondria activation, but it was not influenced by siRNA interference of BiP, an ER regulation protein. While for nuclear irradiation, rotenone-enhanced radiation-induced ER expression, and BiP siRNA eliminated radiation-induced activation of mitochondria, these phenomena were not observed for cytoplasmic irradiation. Bystander MN was reduced by rotenone but enhanced by BiP siRNA. When the cells were treated with both rotenone and BiP siRNA, the MN yield was reduced for nuclear irradiation but was enhanced for cytoplasmic irradiation. Our results suggest that the organelles of mitochondria and ER have different roles in RIBE with respect to nuclear and cytoplasmic irradiation, and the function of ER is a prerequisite for mitochondrial activation.
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Affiliation(s)
- Chen Dong
- Institute of Radiation Medicine, Fudan University, Shanghai 200032, China
| | - Wenzhi Tu
- The Comprehensive Cancer Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201620, China
| | - Mingyuan He
- Institute of Radiation Medicine, Fudan University, Shanghai 200032, China
| | - Jiamei Fu
- Institute of Radiation Medicine, Fudan University, Shanghai 200032, China
| | - Alisa Kobayashi
- Department of Accelerator and Medical Physics, National Institute of Radiological Sciences
| | - Teruaki Konishi
- Department of Single Cell Radiation Biology Group, Institute for Quantum Life Science, National Institutes for Quantum and Radiological Science and Technology, Inage, Chiba 263-8555, Japan
| | - Chunlin Shao
- Institute of Radiation Medicine, Fudan University, Shanghai 200032, China
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16
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Sicari D, Delaunay‐Moisan A, Combettes L, Chevet E, Igbaria A. A guide to assessing endoplasmic reticulum homeostasis and stress in mammalian systems. FEBS J 2019; 287:27-42. [DOI: 10.1111/febs.15107] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/10/2019] [Accepted: 10/23/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Daria Sicari
- Inserm U1242 University of Rennes France
- Centre de lutte contre le cancer Eugène Marquis Rennes France
| | - Agnès Delaunay‐Moisan
- Institute for Integrative Biology of the Cell (I2BC) CEA‐Saclay CNRS ISVJC/SBIGEM Laboratoire Stress Oxydant et Cancer Université Paris‐Saclay Gif‐sur‐Yvette France
| | - Laurent Combettes
- UMRS1174 Université Paris Sud Orsay France
- UMRS1174 Institut National de la Santé et de la Recherche Médicale (Inserm) Orsay France
| | - Eric Chevet
- Inserm U1242 University of Rennes France
- Centre de lutte contre le cancer Eugène Marquis Rennes France
| | - Aeid Igbaria
- Inserm U1242 University of Rennes France
- Centre de lutte contre le cancer Eugène Marquis Rennes France
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17
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Luchetti F, Crinelli R, Nasoni MG, Cesarini E, Canonico B, Guidi L, Zerbinati C, Magnani M, Papa S, Iuliano L. Secosterol-B affects endoplasmic reticulum structure in endothelial cells. J Steroid Biochem Mol Biol 2019; 190:234-241. [PMID: 30991093 DOI: 10.1016/j.jsbmb.2019.04.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/09/2019] [Accepted: 04/11/2019] [Indexed: 11/22/2022]
Abstract
Oxysterols, oxidized derivatives of cholesterol found in LDL and atherosclerotic plaques, trigger several biological responses involved in the initiation and progression of atherosclerosis. Endothelial dysfunction, which occurs when vascular homeostasis is altered, plays a key role in the pathogenesis of several metabolic diseases. The contribution of endoplasmic reticulum (ER) stress to endothelial disfunction is a relatively recent area of investigation. There is a well-established link between LDL oxidation and ER stress but the role played by specific products of lipid oxidation into this interaction is still to be defined. The present study shows that secosterol-B (SEC-B), 3β-hydroxy-5β-hydroxy-B-norcholestane-6βcarboxaldehyde, a cholesterol autoxidation product recently identified in the atherosclerotic plaque, is able to induce ER stress in HUVEC cells, as revealed by significant expansion and change of structure. At low doses, i.e. 1 and 5 μM, cells try to cope with this stress by activating autophagy and the ubiquitin proteasome system in the attempt to restore ER function. However, at higher doses, i.e. 20 μM, cell apoptosis occurs in a pathway that involves early phosphorylation of eIF2α and NF-kB activation, suggesting that the adaptive program fails and the cell activates the apoptotic program. These findings provide additional insight about the role of oxysterols in endothelial dysfunction and its potential involvement in atherosclerotic pathophysiology.
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Affiliation(s)
- Francesca Luchetti
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy.
| | - Rita Crinelli
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Maria Gemma Nasoni
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Erica Cesarini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Barbara Canonico
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Loretta Guidi
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Chiara Zerbinati
- Department of Medico-Surgical Sciences and Biotechnology, Sapienza University of Rome, Italy
| | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Stefano Papa
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Luigi Iuliano
- Department of Medico-Surgical Sciences and Biotechnology, Sapienza University of Rome, Italy
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18
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Jevtić P, Schibler AC, Wesley CC, Pegoraro G, Misteli T, Levy DL. The nucleoporin ELYS regulates nuclear size by controlling NPC number and nuclear import capacity. EMBO Rep 2019; 20:embr.201847283. [PMID: 31085625 DOI: 10.15252/embr.201847283] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 04/09/2019] [Accepted: 04/11/2019] [Indexed: 12/13/2022] Open
Abstract
How intracellular organelles acquire their characteristic sizes is a fundamental question in cell biology. Given stereotypical changes in nuclear size in cancer, it is important to understand the mechanisms that control nuclear size in human cells. Using a high-throughput imaging RNAi screen, we identify and mechanistically characterize ELYS, a nucleoporin required for post-mitotic nuclear pore complex (NPC) assembly, as a determinant of nuclear size in mammalian cells. ELYS knockdown results in small nuclei, reduced nuclear lamin B2 localization, lower NPC density, and decreased nuclear import. Increasing nuclear import by importin α overexpression rescues nuclear size and lamin B2 import, while inhibiting importin α/β-mediated nuclear import decreases nuclear size. Conversely, ELYS overexpression increases nuclear size, enriches nuclear lamin B2 at the nuclear periphery, and elevates NPC density and nuclear import. Consistent with these observations, knockdown or inhibition of exportin 1 increases nuclear size. Thus, we identify ELYS as a novel positive effector of mammalian nuclear size and propose that nuclear size is sensitive to NPC density and nuclear import capacity.
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Affiliation(s)
- Predrag Jevtić
- Department of Molecular Biology, University of Wyoming, Laramie, WY, USA
| | | | - Chase C Wesley
- Department of Molecular Biology, University of Wyoming, Laramie, WY, USA
| | - Gianluca Pegoraro
- High Throughput Imaging Facility (HiTIF), National Cancer Institute, NIH, Bethesda, MD, USA
| | - Tom Misteli
- National Cancer Institute, NIH, Bethesda, MD, USA
| | - Daniel L Levy
- Department of Molecular Biology, University of Wyoming, Laramie, WY, USA
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19
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Korchynska S, Lutz MI, Borók E, Pammer J, Cinquina V, Fedirko N, Irving AJ, Mackie K, Harkany T, Keimpema E. GPR55 controls functional differentiation of self-renewing epithelial progenitors for salivation. JCI Insight 2019; 4:122947. [PMID: 30830860 PMCID: PMC6478415 DOI: 10.1172/jci.insight.122947] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 01/11/2019] [Indexed: 12/17/2022] Open
Abstract
GPR55, a lipid-sensing receptor, is implicated in cell cycle control, malignant cell mobilization, and tissue invasion in cancer. However, a physiological role for GPR55 is virtually unknown for any tissue type. Here, we localize GPR55 to self-renewing ductal epithelial cells and their terminally differentiated progeny in both human and mouse salivary glands. Moreover, we find GPR55 expression downregulated in salivary gland mucoepidermoid carcinomas and GPR55 reinstatement by antitumor irradiation, suggesting that GPR55 controls renegade proliferation. Indeed, GPR55 antagonism increases cell proliferation and function determination in quasiphysiological systems. In addition, Gpr55-/- mice present ~50% enlarged submandibular glands with many more granulated ducts, as well as disordered endoplasmic reticuli and with glycoprotein content. Next, we hypothesized that GPR55 could also modulate salivation and glycoprotein content by entraining differentiated excretory progeny. Accordingly, GPR55 activation facilitated glycoprotein release by itself, inducing low-amplitude Ca2+ oscillations, as well as enhancing acetylcholine-induced Ca2+ responses. Topical application of GPR55 agonists, which are ineffective in Gpr55-/- mice, into adult rodent submandibular glands increased salivation and saliva glycoprotein content. Overall, we propose that GPR55 signaling in epithelial cells ensures both the life-long renewal of ductal cells and the continuous availability of saliva and glycoproteins for oral health and food intake.
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Affiliation(s)
| | | | - Erzsébet Borók
- Department of Molecular Neurosciences, Center for Brain Research
- Department of Cognitive Neurobiology, Centre for Brain Research, and
| | - Johannes Pammer
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | | | - Nataliya Fedirko
- Department of Human and Animal Physiology, Biological Faculty, Ivan Franko National University of Lviv, Lviv, Ukraine
| | - Andrew J. Irving
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin, Ireland
| | - Ken Mackie
- Gill Center for Biomolecular Sciences, Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, USA
| | - Tibor Harkany
- Department of Molecular Neurosciences, Center for Brain Research
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Erik Keimpema
- Department of Molecular Neurosciences, Center for Brain Research
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20
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Stacchiotti A, Favero G, Lavazza A, Garcia-Gomez R, Monsalve M, Rezzani R. Perspective: Mitochondria-ER Contacts in Metabolic Cellular Stress Assessed by Microscopy. Cells 2018; 8:cells8010005. [PMID: 30577576 PMCID: PMC6356439 DOI: 10.3390/cells8010005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 12/17/2018] [Accepted: 12/19/2018] [Indexed: 01/07/2023] Open
Abstract
The interplay of mitochondria with the endoplasmic reticulum and their connections, called mitochondria-ER contacts (MERCs) or mitochondria-associated ER membranes (MAMs), are crucial hubs in cellular stress. These sites are essential for the passage of calcium ions, reactive oxygen species delivery, the sorting of lipids in whole-body metabolism. In this perspective article, we focus on microscopic evidences of the pivotal role of MERCs/MAMs and their changes in metabolic diseases, like obesity, diabetes, and neurodegeneration.
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Affiliation(s)
- Alessandra Stacchiotti
- Anatomy and Physiopathology Division, Department of Clinical and Experimental Sciences, University of Brescia, Viale Europa 11, 25123 Brescia, Italy.
- Interdipartimental University Center of Research "Adaptation and Regeneration of Tissues and Organs-(ARTO)", University of Brescia, 25123 Brescia, Italy.
- ANZAC Research Institute, Concord Hospital, NSW 2139 Sydney, Australia.
| | - Gaia Favero
- Anatomy and Physiopathology Division, Department of Clinical and Experimental Sciences, University of Brescia, Viale Europa 11, 25123 Brescia, Italy.
| | - Antonio Lavazza
- Istituto Zooprofilattico Sperimentale della Lombardia ed Emilia Romagna-IZSLER, 25124 Brescia, Italy.
| | - Raquel Garcia-Gomez
- Instituto de Investigaciones Biomedicas "Alberto Sols" (CSIC-UAM), 28029 Madrid, Spain.
| | - Maria Monsalve
- Instituto de Investigaciones Biomedicas "Alberto Sols" (CSIC-UAM), 28029 Madrid, Spain.
| | - Rita Rezzani
- Anatomy and Physiopathology Division, Department of Clinical and Experimental Sciences, University of Brescia, Viale Europa 11, 25123 Brescia, Italy.
- Interdipartimental University Center of Research "Adaptation and Regeneration of Tissues and Organs-(ARTO)", University of Brescia, 25123 Brescia, Italy.
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21
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Ooi CP, Smith TK, Gluenz E, Wand NV, Vaughan S, Rudenko G. Blocking variant surface glycoprotein synthesis alters endoplasmic reticulum exit sites/Golgi homeostasis in Trypanosoma brucei. Traffic 2018; 19:391-405. [PMID: 29533496 PMCID: PMC6001540 DOI: 10.1111/tra.12561] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 03/08/2018] [Accepted: 03/08/2018] [Indexed: 12/31/2022]
Abstract
The predominant secretory cargo of bloodstream form Trypanosoma brucei is variant surface glycoprotein (VSG), comprising ~10% total protein and forming a dense protective layer. Blocking VSG translation using Morpholino oligonucleotides triggered a precise pre‐cytokinesis arrest. We investigated the effect of blocking VSG synthesis on the secretory pathway. The number of Golgi decreased, particularly in post‐mitotic cells, from 3.5 ± 0.6 to 2.0 ± 0.04 per cell. Similarly, the number of endoplasmic reticulum exit sites (ERES) in post‐mitotic cells dropped from 3.9 ± 0.6 to 2.7 ± 0.1 eight hours after blocking VSG synthesis. The secretory pathway was still functional in these stalled cells, as monitored using Cathepsin L. Rates of phospholipid and glycosylphosphatidylinositol‐anchor biosynthesis remained relatively unaffected, except for the level of sphingomyelin which increased. However, both endoplasmic reticulum and Golgi morphology became distorted, with the Golgi cisternae becoming significantly dilated, particularly at the trans‐face. Membrane accumulation in these structures is possibly caused by reduced budding of nascent vesicles due to the drastic reduction in the total amount of secretory cargo, that is, VSG. These data argue that the total flux of secretory cargo impacts upon the biogenesis and maintenance of secretory structures and organelles in T. brucei, including the ERES and Golgi.
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Affiliation(s)
- Cher-Pheng Ooi
- Department of Life Sciences, Imperial College London, London, UK
| | - Terry K Smith
- BSRC, School of Biology, University of St. Andrews, St. Andrews, UK
| | - Eva Gluenz
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | | | - Sue Vaughan
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
| | - Gloria Rudenko
- Department of Life Sciences, Imperial College London, London, UK
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22
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Abstract
The endoplasmic reticulum (ER) is a morphologically dynamic organelle containing different membrane subdomains with distinct cellular functions. Numerous observations have revealed that ER stress response induced by disturbed ER homeostasis is linked to various neurological/neurodegenerative disorders. In contrast, recent findings unveil that ER structural derangements are linked to the progression of several neurological diseases. The derangements involve two distinct, and likely opposing pathways. One is dysfunction of ER dynamics machinery, leading to disruption of ER network organization. Another one is facilitation of pre-existing machinery, leading to generation of markedly-ordered de novo membranous structure. Restoring the ER network can be the effective way toward the cure of ER-deranged neurological disorders.
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Affiliation(s)
- Tomoyuki Yamanaka
- Laboratory of Structural Neuropathology, Graduate School of Brain Science, Doshisha University, Kyoto, Japan
| | - Nobuyuki Nukina
- Laboratory of Structural Neuropathology, Graduate School of Brain Science, Doshisha University, Kyoto, Japan
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23
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Abstract
The endoplasmic reticulum (ER) is the largest membrane-bound organelle in cells, and its size needs to be carefully controlled. Downsizing the ER by autophagy is now shown to involve Sec62, a protein that also helps to build up the organelle. This link suggests a molecular switch for ER size control.
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24
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Boenisch MJ, Broz KL, Purvine SO, Chrisler WB, Nicora CD, Connolly LR, Freitag M, Baker SE, Kistler HC. Structural reorganization of the fungal endoplasmic reticulum upon induction of mycotoxin biosynthesis. Sci Rep 2017; 7:44296. [PMID: 28287158 PMCID: PMC5347122 DOI: 10.1038/srep44296] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 02/06/2017] [Indexed: 12/29/2022] Open
Abstract
Compartmentalization of metabolic pathways to particular organelles is a hallmark of eukaryotic cells. Knowledge of the development of organelles and attendant pathways under different metabolic states has been advanced by live cell imaging and organelle specific analysis. Nevertheless, relatively few studies have addressed the cellular localization of pathways for synthesis of fungal secondary metabolites, despite their importance as bioactive compounds with significance to medicine and agriculture. When triggered to produce sesquiterpene (trichothecene) mycotoxins, the endoplasmic reticulum (ER) of the phytopathogenic fungus Fusarium graminearum is reorganized both in vitro and in planta. Trichothecene biosynthetic enzymes accumulate in organized smooth ER with pronounced expansion at perinuclear- and peripheral positions. Fluorescence tagged trichothecene biosynthetic proteins co-localize with the modified ER as confirmed by co-fluorescence and co-purification with known ER proteins. We hypothesize that changes to the fungal ER represent a conserved process in specialized eukaryotic cells such as in mammalian hepatocytes and B-cells.
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Affiliation(s)
| | | | | | | | | | - Lanelle Reine Connolly
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
| | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
| | | | - Harold Corby Kistler
- USDA ARS Cereal Disease Laboratory, St. Paul, MN 55108, USA.,Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, USA
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25
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KOGA D, BOCHIMOTO H, KUSUMI S, USHIKI T, WATANABE T. <b>Changes in the three-dimensional ultrastructure of membranous organelles in male rat pituitary gonadotropes after castration</b>. Biomed Res 2017; 38:1-18. [DOI: 10.2220/biomedres.38.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Daisuke KOGA
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical University
- Division of Microscopic Anatomy and Bio-imaging, Department of Cellular Function, Niigata University Graduate School of Medical and Dental Sciences
| | - Hiroki BOCHIMOTO
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical University
| | - Satoshi KUSUMI
- Division of Morphological Sciences, Kagoshima University Graduate School of Medical and Dental Sciences
| | - Tatsuo USHIKI
- Division of Microscopic Anatomy and Bio-imaging, Department of Cellular Function, Niigata University Graduate School of Medical and Dental Sciences
| | - Tsuyoshi WATANABE
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical University
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26
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Ganapathy S, Li P, Fagman J, Yu T, Lafontant J, Zhang G, Chen C. Low doses of arsenic, via perturbing p53, promotes tumorigenesis. Toxicol Appl Pharmacol 2016; 306:98-104. [DOI: 10.1016/j.taap.2016.07.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 07/12/2016] [Accepted: 07/13/2016] [Indexed: 11/27/2022]
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27
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de Ruijter JC, Koskela EV, Frey AD. Enhancing antibody folding and secretion by tailoring the Saccharomyces cerevisiae endoplasmic reticulum. Microb Cell Fact 2016; 15:87. [PMID: 27216259 PMCID: PMC4878073 DOI: 10.1186/s12934-016-0488-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 05/11/2016] [Indexed: 01/20/2023] Open
Abstract
Background The yeast Saccharomyces cerevisiae provides intriguing possibilities for synthetic biology and bioprocess applications, but its use is still constrained by cellular characteristics that limit the product yields. Considering the production of advanced biopharmaceuticals, a major hindrance lies in the yeast endoplasmic reticulum (ER), as it is not equipped for efficient and large scale folding of complex proteins, such as human antibodies. Results Following the example of professional secretory cells, we show that inducing an ER expansion in yeast by deleting the lipid-regulator gene OPI1 can improve the secretion capacity of full-length antibodies up to fourfold. Based on wild-type and ER-enlarged yeast strains, we conducted a screening of a folding factor overexpression library to identify proteins and their expression levels that enhance the secretion of antibodies. Out of six genes tested, addition of the peptidyl-prolyl isomerase CPR5 provided the most beneficial effect on specific product yield while PDI1, ERO1, KAR2, LHS1 and SIL1 had a mild or even negative effect to antibody secretion efficiency. Combining genes for ER enhancement did not induce any significant additional effect compared to addition of just one element. By combining the Δopi1 strain, with the enlarged ER, with CPR5 overexpression, we were able to boost the specific antibody product yield by a factor of 10 relative to the non-engineered strain. Conclusions Engineering protein folding in vivo is a major task for biopharmaceuticals production in yeast and needs to be optimized at several levels. By rational strain design and high-throughput screening applications we were able to increase the specific secreted antibody yields of S. cerevisiae up to 10-fold, providing a promising strain for further process optimization and platform development for antibody production. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0488-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jorg C de Ruijter
- Department of Biotechnology and Chemical Technology, Aalto University, Kemistintie 1, 02150, Espoo, Finland
| | - Essi V Koskela
- Department of Biotechnology and Chemical Technology, Aalto University, Kemistintie 1, 02150, Espoo, Finland
| | - Alexander D Frey
- Department of Biotechnology and Chemical Technology, Aalto University, Kemistintie 1, 02150, Espoo, Finland.
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28
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Abstract
Magnetotactic bacteria produce chains of membrane-bound organelles that direct the biomineralization of magnetic nanoparticles. These magnetosome compartments are a model for studying the biogenesis and subcellular organization of bacterial organelles. Previous studies have suggested that discrete gene products build and assemble magnetosomes in a stepwise fashion. Here, using an inducible system, we show that the stages of magnetosome formation are highly dynamic and interconnected. During de novo formation, magnetosomes first organize into discontinuous chain fragments that are subsequently connected by the bacterial actin-like protein MamK. We also find that magnetosome membranes are not uniform in size and can grow in a biomineralization-dependent manner. In the absence of biomineralization, magnetosome membranes stall at a diameter of ~50 nm. Those that have initiated biomineralization then expand to significantly larger sizes and accommodate mature magnetic particles. We speculate that such a biomineralization-dependent checkpoint for membrane growth establishes the appropriate conditions within the magnetosome to ensure successful nucleation and growth of magnetic particles. Magnetotactic bacteria make magnetic nanoparticles inside membrane-bound organelles called magnetosomes; however, it is unclear how the magnetosome membrane controls the biomineralization that occurs within this bacterial organelle. We placed magnetosome formation under inducible control in Magnetospirillum magneticum AMB-1 and used electron cryo-tomography to capture magnetosomes in their near-native state as they form de novo. An inducible system provided the key evidence that magnetosome membranes grow continuously unless they have not properly initiated biomineralization. Our finding that the size of a bacterial organelle impacts its biochemical function is a fundamental advance that impacts our perception of organelle formation and can inform future attempts aimed at creating designer magnetic particles.
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29
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Xu Z, Chikka MR, Xia H, Ready DF. Ire1 supports normal ER differentiation in developing Drosophila photoreceptors. J Cell Sci 2016; 129:921-9. [PMID: 26787744 PMCID: PMC4813318 DOI: 10.1242/jcs.180406] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 01/12/2016] [Indexed: 01/09/2023] Open
Abstract
The endoplasmic reticulum (ER) serves virtually all aspects of cell physiology and, by pathways that are incompletely understood, is dynamically remodeled to meet changing cell needs. Inositol-requiring enzyme 1 (Ire1), a conserved core protein of the unfolded protein response (UPR), participates in ER remodeling and is particularly required during the differentiation of cells devoted to intense secretory activity, so-called 'professional' secretory cells. Here, we characterize the role of Ire1 in ER differentiation in the developing Drosophila compound eye photoreceptors (R cells). As part of normal development, R cells take a turn as professional secretory cells with a massive secretory effort that builds the photosensitive membrane organelle, the rhabdomere. We find rough ER sheets proliferate as rhabdomere biogenesis culminates, and Ire1 is required for normal ER differentiation. Ire1 is active early in R cell development and is required in anticipation of peak biosynthesis. Without Ire1, the amount of rough ER sheets is strongly reduced and the extensive cortical ER network at the rhabdomere base, the subrhabdomere cisterna (SRC), fails. Instead, ER proliferates in persistent and ribosome-poor tubular tangles. A phase of Ire1 activity early in R cell development thus shapes dynamic ER.
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Affiliation(s)
- Zuyuan Xu
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | | | - Hongai Xia
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Donald F Ready
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
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30
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Feng J, Gong D, Fu X, Wu TT, Wang J, Chang J, Zhou J, Lu G, Wang Y, Sun R. M1 of Murine Gamma-Herpesvirus 68 Induces Endoplasmic Reticulum Chaperone Production. Sci Rep 2015; 5:17228. [PMID: 26615759 PMCID: PMC4663489 DOI: 10.1038/srep17228] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 10/27/2015] [Indexed: 12/11/2022] Open
Abstract
Viruses rely on host chaperone network to support their infection. In particular, the endoplasmic reticulum (ER) resident chaperones play key roles in synthesizing and processing viral proteins. Influx of a large amount of foreign proteins exhausts the folding capacity in ER and triggers the unfolded protein response (UPR). A fully-executed UPR comprises signaling pathways that induce ER folding chaperones, increase protein degradation, block new protein synthesis and may eventually activate apoptosis, presenting both opportunities and threats to the virus. Here, we define a role of the MHV-68M1 gene in differential modulation of UPR pathways to enhance ER chaperone production. Ectopic expression of M1 markedly induces ER chaperone genes and expansion of ER. The M1 protein accumulates in ER during infection and this localization is indispensable for its function, suggesting M1 acts from the ER. We found that M1 protein selectively induces the chaperon-producing pathways (IRE1, ATF6) while, interestingly, sparing the translation-blocking arm (PERK). We identified, for the first time, a viral factor capable of selectively intervening the initiation of ER stress signaling to induce chaperon production. This finding provides a unique opportunity of using viral protein as a tool to define the activation mechanisms of individual UPR pathways.
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Affiliation(s)
- Jiaying Feng
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California 90095.,Zhejiang University, Hangzhou, People's Republic of China
| | - Danyang Gong
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California 90095
| | - Xudong Fu
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California 90095.,Zhejiang University, Hangzhou, People's Republic of China
| | - Ting-Ting Wu
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California 90095
| | - Jane Wang
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California 90095
| | - Jennifer Chang
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California 90095
| | - Jingting Zhou
- Zhejiang University, Hangzhou, People's Republic of China.,Department of Anesthesiology, University of California, Los Angeles, California 90095
| | - Gang Lu
- Department of Anesthesiology, University of California, Los Angeles, California 90095
| | - Yibin Wang
- Department of Anesthesiology, University of California, Los Angeles, California 90095
| | - Ren Sun
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California 90095.,Zhejiang University, Hangzhou, People's Republic of China
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31
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Kikuchi H, Kuribayashi F, Mimuro H, Imajoh-Ohmi S, Nakayama M, Takami Y, Nishitoh H, Nakayama T. Lack of GCN5 remarkably enhances the resistance against prolonged endoplasmic reticulum stress-induced apoptosis through up-regulation of Bcl-2 gene expression. Biochem Biophys Res Commun 2015; 463:870-5. [PMID: 26086109 DOI: 10.1016/j.bbrc.2015.06.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 06/04/2015] [Indexed: 12/20/2022]
Abstract
The endoplasmic reticulum (ER), a complex membrane structure, has important roles in all eukaryotic cells. Catastrophe of its functions would lead to ER stress that causes various diseases such as cancer, neurodegenerative diseases, diabetes and so on. Prolonged ER stress could trigger apoptosis via activation of various signal transduction pathways. To investigate physiological roles of histone acetyltransferase GCN5 in regulation of ER stress, we analyzed responses of homozygous GCN5-deficient DT40 mutants, ΔGCN5, against ER stress. GCN5-deficiency in DT40 caused drastic resistance against apoptosis induced by pharmacological ER stress agents (thapsigargin and tunicamycin). Pharmaceutical analysis using specific Bcl-2 inhibitors showed that the drastic resistance against prolonged ER stress-induced apoptosis is, in part, due to up-regulation of Bcl-2 gene expression in ΔGCN5. These data revealed that GCN5 is involved in regulation of prolonged ER stress-induced apoptosis through controlling Bcl-2 gene expression.
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Affiliation(s)
- Hidehiko Kikuchi
- Section of Biochemistry and Molecular Biology, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200, Kihara, Kiyotake, Miyazaki 889-1692, Japan; Division of Bacteriology, Department of Infectious Diseases Control, International Research Center for Infectious Diseases, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
| | - Futoshi Kuribayashi
- Division of Bacteriology, Department of Infectious Diseases Control, International Research Center for Infectious Diseases, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan; Department of Biochemistry, Kawasaki Medical School, 577, Matsushima, Kurashiki, Okayama 701-0192, Japan
| | - Hitomi Mimuro
- Division of Bacteriology, Department of Infectious Diseases Control, International Research Center for Infectious Diseases, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Shinobu Imajoh-Ohmi
- Laboratory Center for Proteomics Research, Graduate School of Frontier Sciences, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Masami Nakayama
- Section of Biochemistry and Molecular Biology, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200, Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Yasunari Takami
- Section of Biochemistry and Molecular Biology, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200, Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Hideki Nishitoh
- Section of Biochemistry and Molecular Biology, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200, Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Tatsuo Nakayama
- Section of Biochemistry and Molecular Biology, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200, Kihara, Kiyotake, Miyazaki 889-1692, Japan
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32
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Li J, Chen Z, Gao LY, Colorni A, Ucko M, Fang S, Du SJ. A transgenic zebrafish model for monitoring xbp1 splicing and endoplasmic reticulum stress in vivo. Mech Dev 2015; 137:33-44. [PMID: 25892297 DOI: 10.1016/j.mod.2015.04.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 04/07/2015] [Accepted: 04/08/2015] [Indexed: 12/26/2022]
Abstract
Accumulation of misfolded or unfolded proteins in the endoplasmic reticulum (ER) triggers ER stress that initiates unfolded protein response (UPR). XBP1 is a transcription factor that mediates one of the key signaling pathways of UPR to cope with ER stress through regulating gene expression. Activation of XBP1 involves an unconventional mRNA splicing catalyzed by IRE1 endonuclease that removes an internal 26 nucleotides from xbp1 mRNA transcripts in the cytoplasm. Researchers have taken advantage of this unique activation mechanism to monitor XBP1 activation, thereby UPR, in cell culture and transgenic models. Here we report a Tg(ef1α:xbp1δ-gfp) transgenic zebrafish line to monitor XBP1 activation using GFP as a reporter especially in zebrafish oocytes and developing embryos. The Tg(ef1α:xbp1δ-gfp) transgene was constructed using part of the zebrafish xbp1 cDNA containing the splicing element. ER stress induced splicing results in the cDNA encoding a GFP-tagged partial XBP1 without the transactivation activation domain (XBP1Δ-GFP). The results showed that xbp1 transcripts mainly exist as the spliced active isoform in unfertilized oocytes and zebrafish embryos prior to zygotic gene activation at 3 hours post fertilization. A strong GFP expression was observed in unfertilized oocytes, eyes, brain and skeletal muscle in addition to a weak expression in the hatching gland. Incubation of transgenic zebrafish embryos with (dithiothreitol) DTT significantly induced XBP1Δ-GFP expression. Collectively, these studies unveil the presence of maternal xbp1 splicing in zebrafish oocytes, fertilized eggs and early stage embryos. The Tg(ef1α:xbp1δ-gfp) transgenic zebrafish provides a useful model for in vivo monitoring xbp1 splicing during development and under ER stress conditions.
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Affiliation(s)
- Junling Li
- Institute of Marine and Environmental Technology, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Shandong Medicinal and Biotechnology Center, Shandong Academy of Medical Sciences, Jinan 250062, Shandong Province, China
| | - Zhiliang Chen
- Institute of Marine and Environmental Technology, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Lian-Yong Gao
- Department of cell Biology and Molecular genetics, University of Maryland, College Park, MD 20742, USA
| | - Angelo Colorni
- Israel Oceanographic and Limnological Research, National Center for Mariculture, Eilat 88112, Israel
| | - Michal Ucko
- Israel Oceanographic and Limnological Research, National Center for Mariculture, Eilat 88112, Israel
| | - Shengyun Fang
- Center for Biomedical Engineering and Technology, Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Shao Jun Du
- Institute of Marine and Environmental Technology, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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33
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Georgieva M, Staneva D, Uzunova K, Efremov T, Balashev K, Harata M, Miloshev G. The linker histone in Saccharomyces cerevisiae interacts with actin-related protein 4 and both regulate chromatin structure and cellular morphology. Int J Biochem Cell Biol 2015; 59:182-92. [DOI: 10.1016/j.biocel.2014.12.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 12/15/2014] [Indexed: 11/28/2022]
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34
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Goodwin EC, Motamedi N, Lipovsky A, Fernández-Busnadiego R, DiMaio D. Expression of DNAJB12 or DNAJB14 causes coordinate invasion of the nucleus by membranes associated with a novel nuclear pore structure. PLoS One 2014; 9:e94322. [PMID: 24732912 PMCID: PMC3986390 DOI: 10.1371/journal.pone.0094322] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 03/15/2014] [Indexed: 11/18/2022] Open
Abstract
DNAJB12 and DNAJB14 are transmembrane proteins in the endoplasmic reticulum (ER) that serve as co-chaperones for Hsc70/Hsp70 heat shock proteins. We demonstrate that over-expression of DNAJB12 or DNAJB14 causes the formation of elaborate membranous structures within cell nuclei, which we designate DJANGOS for DNAJ-associated nuclear globular structures. DJANGOS contain DNAJB12, DNAJB14, Hsc70 and markers of the ER lumen and ER and nuclear membranes. Strikingly, they are evenly distributed underneath the nuclear envelope and are of uniform size in any one nucleus. DJANGOS are composed primarily of single-walled membrane tubes and sheets that connect to the nuclear envelope via a unique configuration of membranes, in which the nuclear pore complex appears anchored exclusively to the outer nuclear membrane, allowing both the inner and outer nuclear membranes to flow past the circumference of the nuclear pore complex into the nucleus. DJANGOS break down rapidly during cell division and reform synchronously in the daughter cell nuclei, demonstrating that they are dynamic structures that undergo coordinate formation and dissolution. Genetic studies showed that the chaperone activity of DNAJ/Hsc70 is required for the formation of DJANGOS. Further analysis of these structures will provide insight into nuclear pore formation and function, activities of molecular chaperones, and mechanisms that maintain membrane identity.
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Affiliation(s)
- Edward C. Goodwin
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Nasim Motamedi
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Alex Lipovsky
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, United States of America
| | | | - Daniel DiMaio
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, United States of America
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics & Biochemistry, Yale School of Medicine, New Haven, Connecticut, United States of America
- Yale Cancer Center, New Haven, Connecticut, United States of America
- * E-mail:
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35
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McManaman JL. Lipid transport in the lactating mammary gland. J Mammary Gland Biol Neoplasia 2014; 19:35-42. [PMID: 24567110 PMCID: PMC4413448 DOI: 10.1007/s10911-014-9318-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 02/04/2014] [Indexed: 12/11/2022] Open
Abstract
Mammalian cells depend on phospholipid (PL) and fatty acid (FA) transport to maintain membrane structure and organization, and to fuel and regulate cellular functions. In mammary glands of lactating animals, copious milk secretion, including large quantities of lipid in some species, requires adaptation and integration of PL and FA synthesis and transport processes to meet secretion demands. At present few details exist about how these processes are regulated within the mammary gland. However, recent advances in our understanding of the structural and molecular biology of membrane systems and cellular lipid trafficking provide insights into the mechanisms underlying the regulation and integration of PL and FA transport processes the lactating mammary gland. This review discusses the PL and FA transport processes required to maintain the structural integrity and organization of the mammary gland and support its secretory functions within the context of current molecular and cellular models of their regulation.
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Affiliation(s)
- James L McManaman
- Division of Basic Reproductive Sciences, University of Colorado School of Medicine, Mail Stop 8613, 12700 E. 19th Ave., Aurora, CO, 80045, USA,
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36
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NF-Y inactivation causes atypical neurodegeneration characterized by ubiquitin and p62 accumulation and endoplasmic reticulum disorganization. Nat Commun 2014; 5:3354. [PMID: 24566496 DOI: 10.1038/ncomms4354] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 01/30/2014] [Indexed: 12/23/2022] Open
Abstract
Nuclear transcription factor-Y (NF-Y), a key regulator of cell-cycle progression, often loses its activity during differentiation into nonproliferative cells. In contrast, NF-Y is still active in mature, differentiated neurons, although its neuronal significance remains obscure. Here we show that conditional deletion of the subunit NF-YA in postmitotic mouse neurons induces progressive neurodegeneration with distinctive ubiquitin/p62 pathology; these proteins are not incorporated into filamentous inclusion but co-accumulated with insoluble membrane proteins broadly on endoplasmic reticulum (ER). The degeneration also accompanies drastic ER disorganization, that is, an aberrant increase in ribosome-free ER in the perinuclear region, without inducing ER stress response. We further perform chromatin immunoprecipitation and identify several NF-Y physiological targets including Grp94 potentially involved in ER disorganization. We propose that NF-Y is involved in a unique regulation mechanism of ER organization in mature neurons and its disruption causes previously undescribed novel neuropathology accompanying abnormal ubiquitin/p62 accumulation.
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37
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Fossati M, Borgese N, Colombo SF, Francolini M. Visualization of endoplasmic reticulum subdomains in cultured cells. J Vis Exp 2014:e50985. [PMID: 24637314 DOI: 10.3791/50985] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The lipids and proteins in eukaryotic cells are continuously exchanged between cell compartments, although these retain their distinctive composition and functions despite the intense interorganelle molecular traffic. The techniques described in this paper are powerful means of studying protein and lipid mobility and trafficking in vivo and in their physiological environment. Fluorescence recovery after photobleaching (FRAP) and fluorescence loss in photobleaching (FLIP) are widely used live-cell imaging techniques for studying intracellular trafficking through the exo-endocytic pathway, the continuity between organelles or subcompartments, the formation of protein complexes, and protein localization in lipid microdomains, all of which can be observed under physiological and pathological conditions. The limitations of these approaches are mainly due to the use of fluorescent fusion proteins, and their potential drawbacks include artifactual over-expression in cells and the possibility of differences in the folding and localization of tagged and native proteins. Finally, as the limit of resolution of optical microscopy (about 200 nm) does not allow investigation of the fine structure of the ER or the specific subcompartments that can originate in cells under stress (i.e. hypoxia, drug administration, the over-expression of transmembrane ER resident proteins) or under pathological conditions, we combine live-cell imaging of cultured transfected cells with ultrastructural analyses based on transmission electron microscopy.
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Affiliation(s)
- Matteo Fossati
- Fondazione Filarete; Department of Biotechnology and Translational Medicine, University of Milan; Neuroscience Institute, National Research Council (CNR)
| | - Nica Borgese
- Department of Biotechnology and Translational Medicine, University of Milan; Neuroscience Institute, National Research Council (CNR); Department of Health Science, "Magna Graecia" University of Catanzaro
| | - Sara Francesca Colombo
- Department of Biotechnology and Translational Medicine, University of Milan; Neuroscience Institute, National Research Council (CNR)
| | - Maura Francolini
- Fondazione Filarete; Department of Biotechnology and Translational Medicine, University of Milan;
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SERCA2 dysfunction in Darier disease causes endoplasmic reticulum stress and impaired cell-to-cell adhesion strength: rescue by Miglustat. J Invest Dermatol 2014; 134:1961-1970. [PMID: 24390139 DOI: 10.1038/jid.2014.8] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 10/31/2013] [Accepted: 12/09/2013] [Indexed: 12/17/2022]
Abstract
Darier disease (DD) is a severe dominant genetic skin disorder characterized by the loss of cell-to-cell adhesion and abnormal keratinization. The defective gene, ATP2A2, encodes sarco/endoplasmic reticulum (ER) Ca2+ -ATPase isoform 2 (SERCA2), a Ca2+ -ATPase pump of the ER. Here we show that Darier keratinocytes (DKs) display biochemical and morphological hallmarks of constitutive ER stress with increased sensitivity to ER stressors. Desmosome and adherens junctions (AJs) displayed features of immature adhesion complexes: expression of desmosomal cadherins (desmoglein 3 (Dsg3) and desmocollin 3 (Dsc3)) and desmoplakin was impaired at the plasma membrane, as well as E-cadherin, β-, α-, and p120-catenin staining. Dsg3, Dsc3, and E-cadherin showed perinuclear staining and co-immunostaining with ER markers, indicative of ER retention. Consistent with these abnormalities, intercellular adhesion strength was reduced as shown by a dispase mechanical dissociation assay. Exposure of normal keratinocytes to the SERCA2 inhibitor thapsigargin recapitulated these abnormalities, supporting the role of loss of SERCA2 function in impaired desmosome and AJ formation. Remarkably, treatment of DKs with the orphan drug Miglustat, a pharmacological chaperone, restored mature AJ and desmosome formation, and improved adhesion strength. These results point to an important contribution of ER stress in DD pathogenesis and provide the basis for future clinical evaluation of Miglustat in Darier patients.
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39
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Teng CY, Chang SL, van Oers MM, Wu TY. Enhanced protein secretion from insect cells by co-expression of the chaperone calreticulin and translation initiation factor eIF4E. Mol Biotechnol 2013; 54:68-78. [PMID: 22555850 DOI: 10.1007/s12033-012-9545-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Host protein synthesis is shut down in the lytic baculovirus expression vector system (BEVS). This also affects host proteins involved in routing secretory proteins through the endoplasmic reticulum (ER)-Golgi system. It has been demonstrated that a secretory alkaline phosphatase-EGFP fusion protein (SEFP) can act as a traceable and sensitive secretory reporter protein in BEVS. In this study, a chaperone, calreticulin (CALR), and the translation initiation factor eIF4E were co-expressed with SEFP using a bicistronic baculovirus expression vector. We observed that the intracellular distribution of SEFP in cells co-expressing CALR was different from co-expressing eIF4E. The increased green fluorescence emitted by cells co-expressing CALR had a good correlation with the abundance of intracellular SEFP protein and an unconventional ER expansion. Cells co-expressing eIF4E, on the other hand, showed an increase in extracellular SEAP activity compared to the control. Utilization of these baculovirus expression constructs containing either eIF4E or CALR offers a significant advantage for producing secreted proteins for various biotechnological and therapeutic applications.
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Affiliation(s)
- Chao-Yi Teng
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan
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40
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Teng CY, Chang SL, Tsai MF, Wu TY. Α-synuclein and β-synuclein enhance secretion protein production in baculovirus expression vector system. Appl Microbiol Biotechnol 2013; 97:3875-84. [PMID: 23314197 DOI: 10.1007/s00253-012-4679-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 12/20/2012] [Accepted: 12/22/2012] [Indexed: 11/26/2022]
Abstract
The baculovirus expression vector system (BEVS) is widely used as a tool for expressing of recombinant proteins in insect cells or larvae. However, the expression level of secretion pathway proteins is often lower than that of cytosolic and nucleus proteins. Thus, we attempted to improve production of secreted proteins by using a secretory alkaline phosphatase-EGFP fusion protein (SEFP)-based bi-cistronic baculovirus vector to identify chaperones that have potential on boosting secreted protein production. As co-expressed SEFP with a chaperone, calreticulin (CALR), it was found that the secreted SEFP enzyme activity can be boosted up to twofold. This result demonstrated the SEFP-based bi-cistronic approach can be used to identify the genes that can enhance secretion protein production in BEVS. Thus, the chaperone activity of α-synuclein (α-syn) and β-synuclein (β-syn) was evaluated in cells co-expressed with SEFP and compared that with CALR by analyzing localization, alkaline phosphatase enzyme activity, and mRNA expression levels of SEFP. Our results showed that SEFP enzyme activity from cells co-expressed with both synuclein proteins can be enhanced up to 2.3-fold and this increment was better than that caused by CALR. Moreover, this enhancement might arise from the transcription enhancement or higher RNA stability. By this novel approach, we provided evidences that α- and β-syn can enhance secretion proteins production in BEVS.
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Affiliation(s)
- Chao-Yi Teng
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan
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41
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Zhu G, Ye R, Jung DY, Barron E, Friedline RH, Benoit VM, Hinton DR, Kim JK, Lee AS. GRP78 plays an essential role in adipogenesis and postnatal growth in mice. FASEB J 2012. [PMID: 23180827 DOI: 10.1096/fj.12-213330] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
To investigate the role of GRP78 in adipogenesis and metabolic homeostasis, we knocked down GRP78 in mouse embryonic fibroblasts and 3T3-L1 preadipocytes induced to undergo differentiation into adipocytes. We also created an adipose Grp78-knockout mouse utilizing the aP2 (fatty acid binding protein 4) promoter-driven Cre-recombinase. Adipogenesis was monitored by molecular markers and histology. Tissues were analyzed by micro-CT and electron microscopy. Glucose homeostasis and cytokine analysis were performed. Our results indicate that GRP78 is essential for adipocyte differentiation in vitro. aP2-cre-mediated GRP78 deletion leads to lipoatrophy with ∼90% reduction in gonadal and subcutaneous white adipose tissue and brown adipose tissue, severe growth retardation, and bone defects. Despite severe abnormality in adipose mass and function, adipose Grp78-knockout mice showed normal plasma triglyceride levels, and plasma glucose and insulin levels were reduced by 40-60% compared to wild-type mice, suggesting enhanced insulin sensitivity. The endoplasmic reticulum is grossly expanded in the residual mutant white adipose tissue. Thus, these studies establish that GRP78 is required for adipocyte differentiation, glucose homeostasis, and balanced secretion of adipokines. Unexpectedly, the phenotypes and metabolic parameters of the mutant mice, which showed early postnatal mortality, are uniquely distinct from previously characterized lipodystrophic mouse models.
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Affiliation(s)
- Genyuan Zhu
- Department of Biochemistry and Molecular Biology, USC Norris Comprehensive Cancer Center, 1441 Eastlake Ave., Rm. 5308, Los Angeles, CA 90089-9176, USA
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42
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Abstract
Cells have developed ways to sense and control the size of their organelles. Size-sensing mechanisms range from direct measurements provided by dedicated reporters to indirect functional readouts, and they are used to modify organelle size under both normal and stress conditions. Organelle size can also be controlled in the absence of an identifiable size sensor. Studies on flagella have dissected principles of size sensing and control, and it will be exciting to see how these principles apply to other organelles.
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Affiliation(s)
- Yee-Hung M Chan
- Department of Biochemistry and Biophysics, UCSF Center for Systems and Synthetic Biology, University of California, San Francisco, San Francisco, CA 94158, USA.
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Guo J, Zhu T, Chen L, Nishioka T, Tsuji T, Xiao ZXJ, Chen CY. Differential sensitization of different prostate cancer cells to apoptosis. Genes Cancer 2011; 1:836-46. [PMID: 21132068 DOI: 10.1177/1947601910381645] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Revised: 07/02/2010] [Accepted: 07/20/2010] [Indexed: 11/17/2022] Open
Abstract
Although protein kinase C (PKC) plays an important role in sensitizing prostate cancer cells to apoptosis, and suppression of PKC is able to trigger an apoptotic crisis in cells harboring oncogenic ras, little is known about whether dyregulation of Ras effectors in prostate cancer cells, together with loss of PKC, is synthetically lethal. The current study aims at investigating whether prostate cancer cells with aberrant Ras effector signaling are sensitive to treatment with HMG (a PKC inhibitor) for the induction of apoptosis. We show that prostate cancer DU145 cells expressing a high level of JNK1 become susceptible to apoptosis after treatment with HMG, in which caspase 8 is activated and cytochrome c is released to the cytosol. In contrast, the addition of HMG sensitizes LNCaP or PC3 prostate cancer cells harboring an active Akt to apoptosis, in which ROS is upregulated to induce the UPR and GADD153 expression. The concurrent activation of JNK1 and Akt has an additive effect on apoptosis following PKC suppression. Thus, the data identify Akt and JNK1 as potential targets in prostate cancer cells for PKC inhibition-induced apoptosis.
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Affiliation(s)
- Jinjin Guo
- Department of Radiation Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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Chen J, Stefano G, Brandizzi F, Zheng H. Arabidopsis RHD3 mediates the generation of the tubular ER network and is required for Golgi distribution and motility in plant cells. J Cell Sci 2011; 124:2241-52. [PMID: 21652628 DOI: 10.1242/jcs.084624] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
In plant cells, the endoplasmic reticulum (ER) and Golgi apparatus form a unique system in which single Golgi stacks are motile and in close association with the underlying ER tubules. Arabidopsis has three RHD3 (ROOT HAIR DEFECTIVE 3) isoforms that are analogous to the mammalian atlastin GTPases involved in shaping ER tubules. We used live-cell imaging, genetic complementation, split ubiquitin assays and western blot analyses in Arabidopsis and tobacco to show that RHD3 mediates the generation of the tubular ER network and is required for the distribution and motility of Golgi stacks in root and leaf epidermal cells. We established that RHD3 forms homotypic interactions at ER punctae. In addition, the activity of RHD3 on the tubular ER is specifically correlated with the cellular distribution and motility of Golgi stacks because ER to Golgi as well as Golgi to plasma membrane transport was not affected by RHD3 mutations in the conserved GDP/GTP motifs. We found a possible partial redundancy within the RHD3 isoforms in Arabidopsis. However, yeast Sey1p, a functional atlastin homologue, and RHD3 are not interchangeable in complementing the respective loss-of-function mutants, suggesting that the molecular mechanisms controlling ER tubular morphology might not be entirely conserved among eukaryotic lineages.
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Affiliation(s)
- Jun Chen
- Developmental Biology Research Initiatives, Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, QC H3A1B1, Canada
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Shull GE, Miller ML, Prasad V. Secretory pathway stress responses as possible mechanisms of disease involving Golgi Ca2+ pump dysfunction. Biofactors 2011; 37:150-8. [PMID: 21674634 PMCID: PMC3338190 DOI: 10.1002/biof.141] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 12/15/2010] [Indexed: 01/15/2023]
Abstract
In mammalian tissues, uptake of Ca(2+) and Mn(2+) by Golgi membranes is mediated by the secretory pathway Ca(2+) -ATPases, SPCA1 and SPCA2, encoded by the ATP2C1 and ATP2C2 genes. Loss of one copy of the ATP2C1 gene, which causes SPCA1 haploinsufficiency, leads to squamous cell tumors of keratinized epithelia in mice and to Hailey-Hailey disease, an acantholytic skin disease, in humans. Although the disease phenotypes resulting from SPCA1 haploinsufficiency in mice and humans are quite different, each species-specific phenotype is remarkably similar to those arising as a result of null mutations in one copy of the ATP2A2 gene, encoding SERCA2, the endoplasmic reticulum (ER) Ca(2+) pump. SERCA2 haploinsufficiency, like SPCA1 haploinsufficiency, causes squamous cell tumors in mice and Darier's disease, also an acantholytic skin disease, in humans. The phenotypic similarities between SPCA1 and SERCA2 haploinsufficiency in the two species, and the general functions of the two pumps in consecutive compartments of the secretory pathway, suggest that the underlying disease mechanisms are similar. In this review, we discuss evidence supporting the view that chronic Golgi stress and/or ER stress resulting from Ca(2+) pump haploinsufficiencies leads to activation of cellular stress responses in keratinocytes, with the predominance of proapoptotic pathways (although not necessarily apoptosis itself) leading to acantholytic skin disease in humans and the predominance of prosurvival pathways leading to tumors in mice.
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Affiliation(s)
- Gary E Shull
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, College of Medicine, OH, USA.
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46
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Abstract
Biomembranes are traditionally viewed as flat phospholipid-bilayer sheets delineating the cell boundaries and dividing the cell into multiple subcellular organelles with specialized functions. However, biological membranes may also fold up into three-dimensional nanoperiodic arrangements, termed cubic membranes. This type of geometry is mathematically well described and extensively studied in lipidic cubic phase systems. This chapter will (1) summarize similarities and dissimilarities between cubic membranes and cubic phases; (2) provide an update on the experimental data describing the role of lipids, proteins and electrostatic charges on the biogenesis of cubic membranes; and (3) discuss their potential function in intracellular macromolecular transport and as optical filters, as well as potential practical applications such as gene delivery vehicles.
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Affiliation(s)
- Zakaria A Almsherqi
- Cubic Membrane Laboratory, Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Felix Margadant
- Cubic Membrane Laboratory, Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Yuru Deng
- Cubic Membrane Laboratory, Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Manandhar SP, Hildebrandt ER, Jacobsen WH, Santangelo GM, Schmidt WK. Chemical inhibition of CaaX protease activity disrupts yeast Ras localization. Yeast 2010; 27:327-43. [PMID: 20162532 DOI: 10.1002/yea.1756] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Proteins possessing a C-terminal CaaX motif, such as the Ras GTPases, undergo extensive post-translational modification that includes attachment of an isoprenoid lipid, proteolytic processing and carboxylmethylation. Inhibition of the enzymes involved in these processes is considered a cancer-therapeutic strategy. We previously identified nine in vitro inhibitors of the yeast CaaX protease Rce1p in a chemical library screen (Manandhar et al., 2007). Here, we demonstrate that these agents disrupt the normal plasma membrane distribution of yeast GFP-Ras reporters in a manner that pharmacologically phenocopies effects observed upon genetic loss of CaaX protease function. Consistent with Rce1p being the in vivo target of the inhibitors, we observe that compound-induced delocalization is suppressed by increasing the gene dosage of RCE1. Moreover, we observe that Rce1p biochemical activity associated with inhibitor-treated cells is inversely correlated with compound dose. Genetic loss of CaaX proteolysis results in mistargeting of GFP-Ras2p to subcellular foci that are positive for the endoplasmic reticulum marker Sec63p. Pharmacological inhibition of CaaX protease activity also delocalizes GFP-Ras2p to foci, but these foci are not as strongly positive for Sec63p. Lastly, we demonstrate that heterologously expressed human Rce1p can mediate proper targeting of yeast Ras and that its activity can also be perturbed by some of the above inhibitors. Together, these results indicate that disrupting the proteolytic modification of Ras GTPases impacts their in vivo trafficking.
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Affiliation(s)
- Surya P Manandhar
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
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48
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Chan YHM, Marshall WF. Scaling properties of cell and organelle size. Organogenesis 2010; 6:88-96. [PMID: 20885855 PMCID: PMC2901812 DOI: 10.4161/org.6.2.11464] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Accepted: 02/08/2010] [Indexed: 11/19/2022] Open
Abstract
How size is controlled is a fundamental question in biology. In this review, we discuss the use of scaling relationships-for example, power-laws of the form y∝x(α)-to provide a framework for comparison and interpretation of size measurements. Such analysis can illustrate the biological and physical principles underlying observed trends, as has been proposed for the allometric dependence of metabolic rate or limb structure on organism mass. Techniques for measuring size at smaller length-scales continue to improve, leading to more data on the control of size in cells and organelles. Size scaling of these structures is expected to influence growth patterns, functional capacity and intracellular transport. Furthermore, organelles such as the nucleus, mitochondria and endoplasmic reticulum show widely varying morphologies that affect their scaling properties. We provide brief summaries of these issues for individual organelles, and conclude with a discussion on how to apply this concept to better understand the mechanisms of size control in the cellular environment.
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Affiliation(s)
- Yee-Hung M Chan
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.
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49
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Intracellular Ca2+ storage in health and disease: a dynamic equilibrium. Cell Calcium 2010; 47:297-314. [PMID: 20189643 DOI: 10.1016/j.ceca.2010.02.001] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 01/31/2010] [Accepted: 02/01/2010] [Indexed: 12/17/2022]
Abstract
Homeostatic control of the endoplasmic reticulum (ER) both as the site for protein handling (synthesis, folding, trafficking, disaggregation and degradation) and as a Ca2+ store is of crucial importance for correct functioning of the cell. Disturbance of the homeostatic control mechanisms leads to a vast array of severe pathologies. The Ca2+ content of the ER is a dynamic equilibrium between active uptake via Ca2+ pumps and Ca2+ release by a number of highly regulated Ca2+-release channels. Regulation of the Ca2+-release channels is very complex and several mechanisms are still poorly understood or controversial. There is increasing evidence that a number of unrelated proteins, either by themselves or in association with other Ca2+ channels, can provide additional Ca2+-leak pathways. The ER is a dynamic organelle and changes in its size and components have been described, either as a result of (de)differentiation processes affecting the secretory capacity of cells, or as a result of adaptation mechanisms to diverse stress conditions such as the unfolded protein response and autophagy. In this review we want to give an overview of the current knowledge of the (short-term) regulatory mechanisms that affect Ca2+-release and Ca2+-leak pathways and of the (long-term) adaptations in ER size and capacity. Understanding of the consequences of these mechanisms for cellular Ca2+ signaling could provide a huge therapeutic potential.
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50
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Christis C, Fullaondo A, Schildknegt D, Mkrtchian S, Heck AJR, Braakman I. Regulated increase in folding capacity prevents unfolded protein stress in the ER. J Cell Sci 2010; 123:787-94. [PMID: 20144991 DOI: 10.1242/jcs.041111] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Stimulation of thyrocytes with thyroid stimulating hormone (TSH) leads to a morphological change and a massive increase in thyroglobulin (Tg) production. Although Tg is a demanding client of the endoplasmic reticulum (ER), its increase did not result in significant accumulation of unfolded protein in the ER. Instead, ER chaperones and folding enzymes reached maximum synthesis rates immediately after TSH stimulation, before significant upregulation of Tg synthesis. The resulting increase in folding capacity before client protein production prevented cellular unfolded-protein stress, confirmed by the silence of the most conserved branch of the unfolded protein response. Thyrocytes set an example of physiological adaptation of cells to a future potentially stress-causing situation, which suggests a general strategy for both non-secretory and specialized secretory cells.
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Affiliation(s)
- Chantal Christis
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Utrecht University, The Netherlands
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