1
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Merta H, Isogai T, Paul B, Danuser G, Henne WM. Spatial proteomics of ER tubules reveals CLMN, an ER-actin tether at focal adhesions that promotes cell migration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.24.577043. [PMID: 38328045 PMCID: PMC10849733 DOI: 10.1101/2024.01.24.577043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
The endoplasmic reticulum (ER) is structurally and functionally diverse, yet how its functions are organized within morphological subdomains is incompletely understood. Utilizing TurboID-based proximity labeling and CRISPR knock-in technologies, here we map the proteomic landscape of the human ER and nuclear envelope. Spatial proteomics reveals enrichments of proteins into ER tubules, sheets, and nuclear envelope. We uncover an ER-enriched actin-binding protein, Calmin (CLMN), and define it as an ER-actin tether that localizes to focal adhesions adjacent to ER tubules. CLMN depletion perturbs focal adhesion disassembly, actin dynamics, and cell movement. Mechanistically, CLMN-depleted cells also exhibit defects in calcium signaling near ER-actin interfaces, suggesting CLMN promotes calcium signaling near adhesions to facilitate their disassembly. Collectively, we map the sub-organelle proteome landscape of the ER, identify CLMN as an ER-actin tether, and describe a non-canonical mechanism by which ER tubules engage actin to regulate cell migration.
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Affiliation(s)
- Holly Merta
- Department of Cell Biology, UT Southwestern Medical Center, Dallas TX 75390
| | - Tadamoto Isogai
- Lyda Hill Department of Bioinformatics and Cecil H. and Ida Green Center for Systems Biology, UT Southwestern Medical Center, Dallas TX 75390
| | - Blessy Paul
- Department of Cell Biology, UT Southwestern Medical Center, Dallas TX 75390
| | - Gaudenz Danuser
- Department of Cell Biology, UT Southwestern Medical Center, Dallas TX 75390
- Lyda Hill Department of Bioinformatics and Cecil H. and Ida Green Center for Systems Biology, UT Southwestern Medical Center, Dallas TX 75390
| | - W Mike Henne
- Department of Cell Biology, UT Southwestern Medical Center, Dallas TX 75390
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2
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Gruber L, Jobst M, Kiss E, Karasová M, Englinger B, Berger W, Del Favero G. Intracellular remodeling associated with endoplasmic reticulum stress modifies biomechanical compliance of bladder cells. Cell Commun Signal 2023; 21:307. [PMID: 37904178 PMCID: PMC10614373 DOI: 10.1186/s12964-023-01295-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 08/23/2023] [Indexed: 11/01/2023] Open
Abstract
Bladder cells face a challenging biophysical environment: mechanical cues originating from urine flow and regular contraction to enable the filling voiding of the organ. To ensure functional adaption, bladder cells rely on high biomechanical compliance, nevertheless aging or chronic pathological conditions can modify this plasticity. Obviously the cytoskeletal network plays an essential role, however the contribution of other, closely entangled, intracellular organelles is currently underappreciated. The endoplasmic reticulum (ER) lies at a crucial crossroads, connected to both nucleus and cytoskeleton. Yet, its role in the maintenance of cell mechanical stability is less investigated. To start exploring these aspects, T24 bladder cancer cells were treated with the ER stress inducers brefeldin A (10-40nM BFA, 24 h) and thapsigargin (0.1-100nM TG, 24 h). Without impairment of cell motility and viability, BFA and TG triggered a significant subcellular redistribution of the ER; this was associated with a rearrangement of actin cytoskeleton. Additional inhibition of actin polymerization with cytochalasin D (100nM CytD) contributed to the spread of the ER toward cell periphery, and was accompanied by an increase of cellular stiffness (Young´s modulus) in the cytoplasmic compartment. Shrinking of the ER toward the nucleus (100nM TG, 2 h) was related to an increased stiffness in the nuclear and perinuclear areas. A similar short-term response profile was observed also in normal human primary bladder fibroblasts. In sum, the ER and its subcellular rearrangement seem to contribute to the mechanical properties of bladder cells opening new perspectives in the study of the related stress signaling cascades. Video Abstract.
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Affiliation(s)
- Livia Gruber
- Department of Food Chemistry and Toxicology, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, Vienna, 1090, Austria
| | - Maximilian Jobst
- Department of Food Chemistry and Toxicology, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, Vienna, 1090, Austria
- Core Facility Multimodal Imaging, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, Vienna, 1090, Austria
- University of Vienna, Vienna Doctoral School in Chemistry (DoSChem), Währinger Str. 42, Vienna, 1090, Austria
| | - Endre Kiss
- Core Facility Multimodal Imaging, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, Vienna, 1090, Austria
| | - Martina Karasová
- Department of Food Chemistry and Toxicology, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, Vienna, 1090, Austria
- Core Facility Multimodal Imaging, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, Vienna, 1090, Austria
| | - Bernhard Englinger
- Department of Urology, Comprehensive Cancer Center, Medical University of Vienna, Vienna, 1090, Austria
- Center for Cancer Research and Comprehensive Cancer Center, Medical University Vienna, Vienna, 1090, Austria
| | - Walter Berger
- Center for Cancer Research and Comprehensive Cancer Center, Medical University Vienna, Vienna, 1090, Austria
| | - Giorgia Del Favero
- Department of Food Chemistry and Toxicology, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, Vienna, 1090, Austria.
- Core Facility Multimodal Imaging, University of Vienna Faculty of Chemistry, Währinger Str. 38-40, Vienna, 1090, Austria.
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3
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Pedersen RT, Snoberger A, Pyrpassopoulos S, Safer D, Drubin DG, Ostap EM. Endocytic myosin-1 is a force-insensitive, power-generating motor. J Cell Biol 2023; 222:e202303095. [PMID: 37549220 PMCID: PMC10406613 DOI: 10.1083/jcb.202303095] [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: 03/23/2023] [Revised: 05/17/2023] [Accepted: 07/24/2023] [Indexed: 08/09/2023] Open
Abstract
Myosins are required for clathrin-mediated endocytosis, but their precise molecular roles in this process are not known. This is, in part, because the biophysical properties of the relevant motors have not been investigated. Myosins have diverse mechanochemical activities, ranging from powerful contractility against mechanical loads to force-sensitive anchoring. To better understand the essential molecular contribution of myosin to endocytosis, we studied the in vitro force-dependent kinetics of the Saccharomyces cerevisiae endocytic type I myosin called Myo5, a motor whose role in clathrin-mediated endocytosis has been meticulously studied in vivo. We report that Myo5 is a low-duty-ratio motor that is activated ∼10-fold by phosphorylation and that its working stroke and actin-detachment kinetics are relatively force-insensitive. Strikingly, the in vitro mechanochemistry of Myo5 is more like that of cardiac myosin than that of slow anchoring myosin-1s found on endosomal membranes. We, therefore, propose that Myo5 generates power to augment actin assembly-based forces during endocytosis in cells.
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Affiliation(s)
- Ross T.A. Pedersen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Aaron Snoberger
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Serapion Pyrpassopoulos
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Daniel Safer
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David G. Drubin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - E. Michael Ostap
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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4
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Pedersen RTA, Snoberger A, Pyrpassopoulos S, Safer D, Drubin DG, Ostap EM. Endocytic myosin-1 is a force-insensitive, power-generating motor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.21.533689. [PMID: 36993306 PMCID: PMC10055380 DOI: 10.1101/2023.03.21.533689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Myosins are required for clathrin-mediated endocytosis, but their precise molecular roles in this process are not known. This is, in part, because the biophysical properties of the relevant motors have not been investigated. Myosins have diverse mechanochemical activities, ranging from powerful contractility against mechanical loads to force-sensitive anchoring. To better understand the essential molecular contribution of myosin to endocytosis, we studied the in vitro force-dependent kinetics of the Saccharomyces cerevisiae endocytic type I myosin called Myo5, a motor whose role in clathrin-mediated endocytosis has been meticulously studied in vivo. We report that Myo5 is a low-duty-ratio motor that is activated ∼10-fold by phosphorylation, and that its working stroke and actin-detachment kinetics are relatively force-insensitive. Strikingly, the in vitro mechanochemistry of Myo5 is more like that of cardiac myosin than like that of slow anchoring myosin-1s found on endosomal membranes. We therefore propose that Myo5 generates power to augment actin assembly-based forces during endocytosis in cells. Summary Pedersen, Snoberger et al. measure the force-sensitivity of the yeast endocytic the myosin-1 called Myo5 and find that it is more likely to generate power than to serve as a force-sensitive anchor in cells. Implications for Myo5's role in clathrin-mediated endocytosis are discussed.
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Affiliation(s)
- Ross TA Pedersen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
- Present address: Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218
- Equal Contribution
| | - Aaron Snoberger
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Equal Contribution
| | - Serapion Pyrpassopoulos
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Daniel Safer
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - David G Drubin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - E Michael Ostap
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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5
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Zhao G, Liu S, Arun S, Renda F, Khodjakov A, Pellman D. A tubule-sheet continuum model for the mechanism of nuclear envelope assembly. Dev Cell 2023; 58:847-865.e10. [PMID: 37098350 PMCID: PMC10205699 DOI: 10.1016/j.devcel.2023.04.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 01/25/2023] [Accepted: 04/01/2023] [Indexed: 04/27/2023]
Abstract
Nuclear envelope (NE) assembly defects cause chromosome fragmentation, cancer, and aging. However, major questions about the mechanism of NE assembly and its relationship to nuclear pathology are unresolved. In particular, how cells efficiently assemble the NE starting from vastly different, cell type-specific endoplasmic reticulum (ER) morphologies is unclear. Here, we identify a NE assembly mechanism, "membrane infiltration," that defines one end of a continuum with another NE assembly mechanism, "lateral sheet expansion," in human cells. Membrane infiltration involves the recruitment of ER tubules or small sheets to the chromatin surface by mitotic actin filaments. Lateral sheet expansion involves actin-independent envelopment of peripheral chromatin by large ER sheets that then extend over chromatin within the spindle. We propose a "tubule-sheet continuum" model that explains the efficient NE assembly from any starting ER morphology, the cell type-specific patterns of nuclear pore complex (NPC) assembly, and the obligatory NPC assembly defect of micronuclei.
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Affiliation(s)
- Gengjing Zhao
- Howard Hughes Medical Institute, Chevy Chase, MD, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA; Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Shiwei Liu
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Sanjana Arun
- Howard Hughes Medical Institute, Chevy Chase, MD, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA; Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Fioranna Renda
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Alexey Khodjakov
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - David Pellman
- Howard Hughes Medical Institute, Chevy Chase, MD, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA; Department of Cell Biology, Harvard Medical School, Boston, MA, USA.
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6
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Arruda AP, Parlakgül G. Endoplasmic Reticulum Architecture and Inter-Organelle Communication in Metabolic Health and Disease. Cold Spring Harb Perspect Biol 2023; 15:cshperspect.a041261. [PMID: 35940911 PMCID: PMC9899651 DOI: 10.1101/cshperspect.a041261] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The endoplasmic reticulum (ER) is a key organelle involved in the regulation of lipid and glucose metabolism, proteostasis, Ca2+ signaling, and detoxification. The structural organization of the ER is very dynamic and complex, with distinct subdomains such as the nuclear envelope and the peripheral ER organized into ER sheets and tubules. ER also forms physical contact sites with all other cellular organelles and with the plasma membrane. Both form and function of the ER are highly adaptive, with a potent capacity to respond to transient changes in environmental cues such as nutritional fluctuations. However, under obesity-induced chronic stress, the ER fails to adapt, leading to ER dysfunction and the development of metabolic pathologies such as insulin resistance and fatty liver disease. Here, we discuss how the remodeling of ER structure and contact sites with other organelles results in diversification of metabolic function and how perturbations to this structural flexibility by chronic overnutrition contribute to ER dysfunction and metabolic pathologies in obesity.
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Affiliation(s)
- Ana Paula Arruda
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, California 94720, USA.,Chan Zuckerberg Biohub, San Francisco, California 94158, USA
| | - Güneş Parlakgül
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, California 94720, USA.,Sabri Ülker Center for Metabolic Research and Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA
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7
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Rizo T, Gebhardt L, Riedlberger J, Eberhardt E, Fester L, Alansary D, Winkler J, Turan S, Arnold P, Niemeyer BA, Fischer MJM, Winner B. Store-operated calcium entry is reduced in spastin-linked hereditary spastic paraplegia. Brain 2022; 145:3131-3146. [PMID: 36103408 PMCID: PMC9473359 DOI: 10.1093/brain/awac122] [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: 01/12/2021] [Revised: 03/17/2022] [Accepted: 03/22/2022] [Indexed: 01/04/2023] Open
Abstract
Pathogenic variants in SPAST, the gene coding for spastin, are the single most common cause of hereditary spastic paraplegia, a progressive motor neuron disease. Spastin regulates key cellular functions, including microtubule-severing and endoplasmic reticulum-morphogenesis. However, it remains unclear how alterations in these cellular functions due to SPAST pathogenic variants result in motor neuron dysfunction. Since spastin influences both microtubule network and endoplasmic reticulum structure, we hypothesized that spastin is necessary for the regulation of Ca2+ homeostasis via store-operated calcium entry. Here, we show that the lack of spastin enlarges the endoplasmic reticulum and reduces store-operated calcium entry. In addition, elevated levels of different spastin variants induced clustering of STIM1 within the endoplasmic reticulum, altered the transport of STIM1 to the plasma membrane and reduced store-operated calcium entry, which could be rescued by exogenous expression of STIM1. Importantly, store-operated calcium entry was strongly reduced in induced pluripotent stem cell-derived neurons from hereditary spastic paraplegia patients with pathogenic variants in SPAST resulting in spastin haploinsufficiency. These neurons developed axonal swellings in response to lack of spastin. We were able to rescue both store-operated calcium entry and axonal swellings in SPAST patient neurons by restoring spastin levels, using CRISPR/Cas9 to correct the pathogenic variants in SPAST. These findings demonstrate that proper amounts of spastin are a key regulatory component for store-operated calcium entry mediated Ca2+ homeostasis and suggest store-operated calcium entry as a disease relevant mechanism of spastin-linked motor neuron disease.
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Affiliation(s)
- Tania Rizo
- Department of Stem Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Lisa Gebhardt
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Julia Riedlberger
- Department of Stem Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Esther Eberhardt
- Present address: Department of Anesthesiology, RWTH Aachen University, 52074 Aachen, Germany
| | - Lars Fester
- Institute of Anatomy and Cell Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Dalia Alansary
- Molecular Biophysics, University of Saarland, Center for Integrative Physiology and Molecular Medicine, 66421 Homburg/Saar, Germany
| | - Jürgen Winkler
- Department of Molecular Neurology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany,Center of Rare Diseases Erlangen (ZSEER), Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Soeren Turan
- Institute of Biochemistry (Emil-Fischer-Center), Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Philipp Arnold
- Institute of Anatomy, Functional and Clinical Anatomy, Friedrich-Alexander-University Erlangen-Nürnberg, 91054 Erlangen, Germany
| | | | | | - Beate Winner
- Correspondence to: Beate Winner Department of Stem Cell Biology Friedrich-Alexander University Erlangen-Nürnberg Glückstraße 6 91054 Erlangen, Germany E-mail:
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8
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Pernier J, Schauer K. Does the Actin Network Architecture Leverage Myosin-I Functions? BIOLOGY 2022; 11:biology11070989. [PMID: 36101369 PMCID: PMC9311500 DOI: 10.3390/biology11070989] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/24/2022] [Accepted: 06/26/2022] [Indexed: 11/16/2022]
Abstract
The actin cytoskeleton plays crucial roles in cell morphogenesis and functions. The main partners of cortical actin are molecular motors of the myosin superfamily. Although our understanding of myosin functions is heavily based on myosin-II and its ability to dimerize, the largest and most ancient class is represented by myosin-I. Class 1 myosins are monomeric, actin-based motors that regulate a wide spectrum of functions, and whose dysregulation mediates multiple human diseases. We highlight the current challenges in identifying the “pantograph” for myosin-I motors: we need to reveal how conformational changes of myosin-I motors lead to diverse cellular as well as multicellular phenotypes. We review several mechanisms for scaling, and focus on the (re-) emerging function of class 1 myosins to remodel the actin network architecture, a higher-order dynamic scaffold that has potential to leverage molecular myosin-I functions. Undoubtfully, understanding the molecular functions of myosin-I motors will reveal unexpected stories about its big partner, the dynamic actin cytoskeleton.
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Affiliation(s)
- Julien Pernier
- Institute for Integrative Biology of the Cell (I2BC), Centre National de la Recherche Scientifique (CNRS), Commissariat à L’Énergie Atomique et aux Énergies Alternatives (CEA), Université Paris-Saclay, 91198 Gif-sur-Yvette, France;
| | - Kristine Schauer
- Tumor Cell Dynamics Unit, Inserm U1279, Gustave Roussy Institute, Université Paris-Saclay, 94800 Villejuif, France
- Correspondence:
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9
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Selçuk E, Kırımtay K, Temizci B, Akarsu Ş, Everest E, Baslo MB, Demirkıran M, Yapıcı Z, Karabay A. MYO1H is a novel candidate gene for autosomal dominant pure hereditary spastic paraplegia. Mol Genet Genomics 2022; 297:1141-1150. [PMID: 35704118 DOI: 10.1007/s00438-022-01910-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 05/23/2022] [Indexed: 11/25/2022]
Abstract
In this study, we aimed to determine the genetic basis of a Turkish family related to hereditary spastic paraplegia (HSP) by exome sequencing. HSP is a progressive neurodegenerative disorder and displays genetic and clinical heterogeneity. The major symptoms are muscle weakness and spasticity, especially in the lower extremities. We studied seven affected and seven unaffected family members, as well as a clinically undetermined member, to identify the disease-causing gene. Exome sequencing was performed for four affected and two unaffected individuals. The variants were firstly filtered for HSP-associated genes, and we found a common variant in the ZFYVE27 gene, which has been previously implied for association with HSP. Due to the incompletely penetrant segregation pattern of the ZFYVE27 variant, revealed by Sanger sequencing, with the disease in this family, filtering was re-performed according to the mode of inheritance and allelic frequencies. The resulting 14 rare variants were further evaluated in terms of their cellular functions, and three candidate variants in ATAD3C, VPS16, and MYO1H genes were selected as possible causative variants, which were analyzed for their familial segregation. ATAD3C and VPS16 variants were eliminated due to incomplete penetrance. Eventually, the MYO1H variant NM_001101421.3:c.2972_2974del (p.Glu992del, rs372231088) was found as the possible disease-causing deletion for HSP in this family. This is the first study reporting the possible role of a MYO1H variant in HSP pathogenesis. Further studies on the cellular roles of Myo1h protein are needed to validate the causality of MYO1H gene at the onset of HSP.
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Affiliation(s)
- Ece Selçuk
- Molecular Biology, Genetics-Biotechnology, Graduate School of Science, Engineering and Technology, Istanbul Technical University, 34469, Istanbul, Turkey
- Department of Molecular Biology and Genetics, Istanbul Medeniyet University, Istanbul, 34700, Turkey
| | - Koray Kırımtay
- Molecular Biology, Genetics-Biotechnology, Graduate School of Science, Engineering and Technology, Istanbul Technical University, 34469, Istanbul, Turkey
| | - Benan Temizci
- Molecular Biology, Genetics-Biotechnology, Graduate School of Science, Engineering and Technology, Istanbul Technical University, 34469, Istanbul, Turkey
- Department of Molecular Biology and Genetics, Istanbul Technical University, Istanbul, 34469, Turkey
| | - Şeyma Akarsu
- Molecular Biology, Genetics-Biotechnology, Graduate School of Science, Engineering and Technology, Istanbul Technical University, 34469, Istanbul, Turkey
- Department of Molecular Biology and Genetics, Istanbul Technical University, Istanbul, 34469, Turkey
| | - Elif Everest
- Molecular Biology, Genetics-Biotechnology, Graduate School of Science, Engineering and Technology, Istanbul Technical University, 34469, Istanbul, Turkey
- Department of Molecular Biology and Genetics, Istanbul Technical University, Istanbul, 34469, Turkey
| | - Mehmet Barış Baslo
- Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, 34093, Istanbul, Turkey
| | - Meltem Demirkıran
- Department of Neurology, Faculty of Medicine, Çukurova University, 01330, Adana, Turkey
| | - Zuhal Yapıcı
- Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, 34093, Istanbul, Turkey
| | - Arzu Karabay
- Molecular Biology, Genetics-Biotechnology, Graduate School of Science, Engineering and Technology, Istanbul Technical University, 34469, Istanbul, Turkey.
- Department of Molecular Biology and Genetics, Istanbul Technical University, Istanbul, 34469, Turkey.
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10
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Lastun VL, Levet C, Freeman M. The mammalian rhomboid protein RHBDL4 protects against endoplasmic reticulum stress by regulating the morphology and distribution of ER sheets. J Biol Chem 2022; 298:101935. [PMID: 35436469 PMCID: PMC9136127 DOI: 10.1016/j.jbc.2022.101935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 03/24/2022] [Accepted: 03/28/2022] [Indexed: 11/16/2022] Open
Abstract
In metazoans, the architecture of the endoplasmic reticulum (ER) differs between cell types and undergoes major changes throughout the cell cycle and according to physiological needs. Although much is known about how the different ER morphologies are generated and maintained, especially ER tubules, how context-dependent changes in ER shape and distribution are regulated and the factors involved are less well characterized, as are the factors that contribute to the positioning of the ER within the cell. By overexpression and KO experiments, we show that the levels of RHBDL4, an ER-resident rhomboid protease, modulate the shape and distribution of the ER, especially during conditions that require rapid changes in the ER sheet distribution, such as ER stress. We demonstrate that RHBDL4 interacts with cytoskeleton-linking membrane protein 63 (CLIMP-63), a protein involved in ER sheet stabilization, as well as with the cytoskeleton. Furthermore, we found that mice lacking RHBDL4 are sensitive to ER stress and develop liver steatosis, a phenotype associated with unresolved ER stress. Taken together, these data suggest a new physiological role for RHBDL4 and also imply that this function does not require its enzymatic activity.
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11
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Janota CS, Pinto A, Pezzarossa A, Machado P, Costa J, Campinho P, Franco CA, Gomes ER. Shielding of actin by the endoplasmic reticulum impacts nuclear positioning. Nat Commun 2022; 13:2763. [PMID: 35589708 PMCID: PMC9120458 DOI: 10.1038/s41467-022-30388-3] [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: 10/14/2021] [Accepted: 04/28/2022] [Indexed: 11/09/2022] Open
Abstract
Nuclear position is central to cell polarization, and its disruption is associated with various pathologies. The nucleus is moved away from the leading edge of migrating cells through its connection to moving dorsal actin cables, and the absence of connections to immobile ventral stress fibers. It is unclear how these asymmetric nucleo-cytoskeleton connections are established. Here, using an in vitro wound assay, we find that remodeling of endoplasmic reticulum (ER) impacts nuclear positioning through the formation of a barrier that shields immobile ventral stress fibers. The remodeling of ER and perinuclear ER accumulation is mediated by the ER shaping protein Climp-63. Furthermore, ectopic recruitment of the ER to stress fibers restores nuclear positioning in the absence of Climp-63. Our findings suggest that the ER mediates asymmetric nucleo-cytoskeleton connections to position the nucleus.
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Affiliation(s)
- Cátia Silva Janota
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Andreia Pinto
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Royal Brompton Hospital and Harefield NHS Foundation Trust, London, UK
| | - Anna Pezzarossa
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Champalimaud Foundation, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Pedro Machado
- Electron Microscopy Core Facility (EMCF), European Molecular Biology Laboratory, Heidelberg, Germany.,Centre for Ultrastructural Imaging, King's College London, London, UK
| | - Judite Costa
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Pedro Campinho
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Champalimaud Foundation, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Cláudio A Franco
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Histologia e Biologia do Desenvolvimento, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Edgar R Gomes
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal. .,Instituto de Histologia e Biologia do Desenvolvimento, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.
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12
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Prospéri MT, Pernier J, Lachuer H, Coudrier E. Plekhh1, a partner of myosin 1 and an effector of EphB2 controls the cortical actin network for cell repulsion. J Cell Sci 2021; 134:272686. [PMID: 34723325 DOI: 10.1242/jcs.258802] [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: 04/17/2021] [Accepted: 10/26/2021] [Indexed: 11/20/2022] Open
Abstract
EphB2/ephrinB signalling that plays a major role in cell segregation during embryonic development and tissue homeostasis, induces an important reorganization of the cortical actin network. We have previously reported that myosin 1b contributes to the reorganisation of the cortical actin network upon EphB2 signalling. In this report we have identified Plekhh1, as a new partner of members of the myosin 1 family and EphB2 receptors. Plekhh1 interacts with myosin 1b via its N-terminus domain and with EphB2 via its C-terminus domain. Furthermore, Plekhh1 is tyrosine-phosphorylated, and this depends on EphB2 kinase activity. Such as the manipulation of the expression level of myosin 1b and myosin 1c, manipulation of Plekhh1 expression levels reveals that Plekhh1 controls the formation of filopodia, the length of focal adhesions and the formation of blebs. Furthermore, binding of Plekhh1 interacting domain to myosin 1b increases the motor activity of myosin 1b in vitro. Together our data show that Plekhh1 is an effector of EphB2 and suggest that Plekhh1 regulates the cortical actin network via the interaction of its N-terminus domain with myosin 1 upon EphB2/ephrinB signalling.
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Affiliation(s)
- Marie-Thérèse Prospéri
- Institut Curie, PSL Research University and C.N.R.S. UMR 144, 26 rue d'Ulm, Paris, France.,Sorbonne Université, 75005 Paris, France
| | - Julien Pernier
- Laboratoire Physico-Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 75005 Paris, France.,Sorbonne Université, 75005 Paris, France
| | - Hugo Lachuer
- Institut Curie, PSL Research University and C.N.R.S. UMR 144, 26 rue d'Ulm, Paris, France.,Sorbonne Université, 75005 Paris, France
| | - Evelyne Coudrier
- Institut Curie, PSL Research University and C.N.R.S. UMR 144, 26 rue d'Ulm, Paris, France.,Sorbonne Université, 75005 Paris, France
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13
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Specific subdomain localization of ER resident proteins and membrane contact sites resolved by electron microscopy. Eur J Cell Biol 2021; 100:151180. [PMID: 34653930 DOI: 10.1016/j.ejcb.2021.151180] [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: 07/07/2021] [Revised: 09/23/2021] [Accepted: 09/28/2021] [Indexed: 11/21/2022] Open
Abstract
The endoplasmic reticulum (ER) is a large, single-copy, membrane-bound organelle that comprises an elaborate 3D network of diverse structural subdomains, including highly curved tubules, flat sheets, and parts that form contacts with nearly every other organelle. The dynamic and complex organization of the ER poses a major challenge on understanding how its functioning - maintenance of the structure, distribution of its functions and communication with other organelles - is orchestrated. In this study, we resolved a unique localization profile within the ER network for several resident ER proteins representing a broad range of functions associated with the ER using immuno-electron microscopy and calculation of a relative labeling index (RLI). Our results demonstrated the effect of changing cellular environment on protein localization and highlighted the importance of correct protein expression level when analyzing its localization at subdomain resolution. We present new software tools for anonymization of images for blind analysis and for quantitative assessment of membrane contact sites (MCSs) from thin section transmission electron microscopy micrographs. The analysis of ER-mitochondria contacts suggested the presence of at least three different types of MCSs that responded differently to changes in cellular lipid loading status.
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14
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Garcia-Pardo ME, Simpson JC, O'Sullivan NC. A novel automated image analysis pipeline for quantifying morphological changes to the endoplasmic reticulum in cultured human cells. BMC Bioinformatics 2021; 22:427. [PMID: 34496765 PMCID: PMC8425006 DOI: 10.1186/s12859-021-04334-x] [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: 04/23/2021] [Accepted: 08/24/2021] [Indexed: 11/10/2022] Open
Abstract
Background In mammalian cells the endoplasmic reticulum (ER) comprises a highly complex reticular morphology that is spread throughout the cytoplasm. This organelle is of particular interest to biologists, as its dysfunction is associated with numerous diseases, which often manifest themselves as changes to the structure and organisation of the reticular network. Due to its complex morphology, image analysis methods to quantitatively describe this organelle, and importantly any changes to it, are lacking. Results In this work we detail a methodological approach that utilises automated high-content screening microscopy to capture images of cells fluorescently-labelled for various ER markers, followed by their quantitative analysis. We propose that two key metrics, namely the area of dense ER and the area of polygonal regions in between the reticular elements, together provide a basis for measuring the quantities of rough and smooth ER, respectively. We demonstrate that a number of different pharmacological perturbations to the ER can be quantitatively measured and compared in our automated image analysis pipeline. Furthermore, we show that this method can be implemented in both commercial and open-access image analysis software with comparable results. Conclusions We propose that this method has the potential to be applied in the context of large-scale genetic and chemical perturbations to assess the organisation of the ER in adherent cell cultures. Supplementary Information The online version contains supplementary material available at 10.1186/s12859-021-04334-x.
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Affiliation(s)
- M Elena Garcia-Pardo
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Jeremy C Simpson
- Cell Screening Laboratory, UCD School of Biology and Environmental Science, University College Dublin, Dublin 4, Ireland
| | - Niamh C O'Sullivan
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin 4, Ireland.
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15
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Intertwined and Finely Balanced: Endoplasmic Reticulum Morphology, Dynamics, Function, and Diseases. Cells 2021; 10:cells10092341. [PMID: 34571990 PMCID: PMC8472773 DOI: 10.3390/cells10092341] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/02/2021] [Accepted: 09/04/2021] [Indexed: 02/07/2023] Open
Abstract
The endoplasmic reticulum (ER) is an organelle that is responsible for many essential subcellular processes. Interconnected narrow tubules at the periphery and thicker sheet-like regions in the perinuclear region are linked to the nuclear envelope. It is becoming apparent that the complex morphology and dynamics of the ER are linked to its function. Mutations in the proteins involved in regulating ER structure and movement are implicated in many diseases including neurodegenerative diseases such as Alzheimer’s, Parkinson’s, and amyotrophic lateral sclerosis (ALS). The ER is also hijacked by pathogens to promote their replication. Bacteria such as Legionella pneumophila and Chlamydia trachomatis, as well as the Zika virus, bind to ER morphology and dynamics-regulating proteins to exploit the functions of the ER to their advantage. This review covers our understanding of ER morphology, including the functional subdomains and membrane contact sites that the organelle forms. We also focus on ER dynamics and the current efforts to quantify ER motion and discuss the diseases related to ER morphology and dynamics.
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16
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Chakrabarti R, Lee M, Higgs HN. Multiple roles for actin in secretory and endocytic pathways. Curr Biol 2021; 31:R603-R618. [PMID: 34033793 DOI: 10.1016/j.cub.2021.03.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Actin filaments play multiple roles in the secretory pathway and in endosome dynamics in mammals, including maintenance of Golgi structure, release of membrane cargo from the trans-Golgi network (TGN), endocytosis, and endosomal sorting dynamics. In addition, TGN carrier transport and endocytosis both occur by multiple mechanisms in mammals. Actin likely plays a role in at least four mammalian endocytic pathways, five pathways for membrane release from the TGN, and three processes involving endosomes. Also, the mammalian Golgi structure is highly dynamic, and actin is likely important for these dynamics. One challenge for many of these processes is the need to deal with other membrane-associated structures, such as the cortical actin network at the plasma membrane or the matrix that surrounds the Golgi. Arp2/3 complex is a major actin assembly factor in most of the processes mentioned, but roles for formins and tandem WH2-motif-containing assembly factors are being elucidated and are anticipated to grow with further study. The specific role for actin has not been defined for most of these processes, but is likely to involve the generation of force for membrane dynamics, either by actin polymerization itself or by myosin motor activity. Defining these processes mechanistically is necessary for understanding membrane dynamics in general, as well as pathways that utilize these processes, such as autophagy.
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Affiliation(s)
- Rajarshi Chakrabarti
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Miriam Lee
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Henry N Higgs
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA.
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17
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Allard A, Lopes Dos Santos R, Campillo C. Remodelling of membrane tubules by the actin cytoskeleton. Biol Cell 2021; 113:329-343. [PMID: 33826772 DOI: 10.1111/boc.202000148] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/25/2021] [Accepted: 03/27/2021] [Indexed: 12/14/2022]
Abstract
Inside living cells, the remodelling of membrane tubules by actomyosin networks is crucial for processes such as intracellular trafficking or organelle reshaping. In this review, we first present various in vivo situations in which actin affects membrane tubule remodelling, then we recall some results on force production by actin dynamics and on membrane tubules physics. Finally, we show that our knowledge of the underlying mechanisms by which actomyosin dynamics affect tubule morphology has recently been moved forward. This is thanks to in vitro experiments that mimic cellular membranes and actin dynamics and allow deciphering the physics of tubule remodelling in biochemically controlled conditions, and shed new light on tubule shape regulation.
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Affiliation(s)
- Antoine Allard
- LAMBE, Université d'Évry, CNRS, CEA, Université Paris-Saclay, Évry-Courcouronnes, 91025, France.,Sorbonne Université, UPMC, Paris 06, Paris, France.,Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, Paris, France.,Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK
| | | | - Clément Campillo
- LAMBE, Université d'Évry, CNRS, CEA, Université Paris-Saclay, Évry-Courcouronnes, 91025, France
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18
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Morphological Heterogeneity of the Endoplasmic Reticulum within Neurons and Its Implications in Neurodegeneration. Cells 2021; 10:cells10050970. [PMID: 33919188 PMCID: PMC8143122 DOI: 10.3390/cells10050970] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/13/2021] [Accepted: 04/19/2021] [Indexed: 12/19/2022] Open
Abstract
The endoplasmic reticulum (ER) is a multipurpose organelle comprising dynamic structural subdomains, such as ER sheets and tubules, serving to maintain protein, calcium, and lipid homeostasis. In neurons, the single ER is compartmentalized with a careful segregation of the structural subdomains in somatic and neurite (axodendritic) regions. The distribution and arrangement of these ER subdomains varies between different neuronal types. Mutations in ER membrane shaping proteins and morphological changes in the ER are associated with various neurodegenerative diseases implying significance of ER morphology in maintaining neuronal integrity. Specific neurons, such as the highly arborized dopaminergic neurons, are prone to stress and neurodegeneration. Differences in morphology and functionality of ER between the neurons may account for their varied sensitivity to stress and neurodegenerative changes. In this review, we explore the neuronal ER and discuss its distinct morphological attributes and specific functions. We hypothesize that morphological heterogeneity of the ER in neurons is an important factor that accounts for their selective susceptibility to neurodegeneration.
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19
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Kumar D, Lak B, Suntio T, Vihinen H, Belevich I, Viita T, Xiaonan L, Vartiainen A, Vartiainen M, Varjosalo M, Jokitalo E. RTN4B interacting protein FAM134C promotes ER membrane curvature and has a functional role in autophagy. Mol Biol Cell 2021; 32:1158-1170. [PMID: 33826365 PMCID: PMC8351555 DOI: 10.1091/mbc.e20-06-0409] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The endoplasmic reticulum (ER) is composed of a controlled ratio of sheets and tubules, which are maintained by several proteins with multiple functions. Reticulons (RTNs), especially RTN4, and DP1/Yop1p family members are known to induce ER membrane curvature. RTN4B is the main RTN4 isoform expressed in nonneuronal cells. In this study, we identified FAM134C as a RTN4B interacting protein in mammalian, nonneuronal cells. FAM134C localized specifically to the ER tubules and sheet edges. Ultrastructural analysis revealed that overexpression of FAM134C induced the formation of unbranched, long tubules or dense globular structures composed of heavily branched narrow tubules. In both cases, tubules were nonmotile. ER tubulation was dependent on the reticulon homology domain (RHD) close to the N-terminus. FAM134C plays a role in the autophagy pathway as its level elevated significantly upon amino acid starvation but not during ER stress. Moreover, FAM134C depletion reduced the number and size of autophagic structures and the amount of ER as a cargo within autophagic structures under starvation conditions. Dominant-negative expression of FAM134C forms with mutated RHD or LC3 interacting region also led to a reduced number of autophagic structures. Our results suggest that FAM134C provides a link between regulation of ER architecture and ER turnover by promoting ER tubulation required for subsequent ER fragmentation and engulfment into autophagosomes.
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Affiliation(s)
| | - Behnam Lak
- Cell and Tissue Dynamics Research Program
| | | | - Helena Vihinen
- Cell and Tissue Dynamics Research Program.,Electron Microscopy Unit, and
| | - Ilya Belevich
- Cell and Tissue Dynamics Research Program.,Electron Microscopy Unit, and
| | | | - Liu Xiaonan
- Molecular Systems Biology Research Group and Proteomics Unit, Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, 00014 Helsinki, Finland
| | | | | | - Markku Varjosalo
- Molecular Systems Biology Research Group and Proteomics Unit, Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, 00014 Helsinki, Finland
| | - Eija Jokitalo
- Cell and Tissue Dynamics Research Program.,Electron Microscopy Unit, and
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20
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Bruno SR, Anathy V. Lung epithelial endoplasmic reticulum and mitochondrial 3D ultrastructure: a new frontier in lung diseases. Histochem Cell Biol 2021; 155:291-300. [PMID: 33598824 PMCID: PMC7889473 DOI: 10.1007/s00418-020-01950-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/24/2020] [Indexed: 12/15/2022]
Abstract
It has long been appreciated that the endoplasmic reticulum (ER) and mitochondria, organelles important for regular cell function and survival, also play key roles in pathogenesis of various lung diseases, including asthma, fibrosis, and infections. Alterations in processes regulated within these organelles, including but not limited to protein folding in the ER and oxidative phosphorylation in the mitochondria, are important in disease pathogenesis. In recent years it has also become increasingly apparent that organelle structure dictates function. It is now clear that organelles must maintain precise organization and localization for proper function. Newer microscopy capabilities have allowed the scientific community to reveal, via 3D imaging, that the structure of these organelles and their interactions with each other are a main component of regulating function and, therefore, effects on the disease state. In this review, we will examine how 3D imaging through techniques could allow advancements in knowledge of how the ER and mitochondria function and the roles they may play in lung epithelia in progression of lung disease.
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Affiliation(s)
- Sierra R Bruno
- Department of Pathology and Laboratory Medicine, University of Vermont, Larner College of Medicine, 149 Beaumont Ave, Burlington, VT, 05405, USA
| | - Vikas Anathy
- Department of Pathology and Laboratory Medicine, University of Vermont, Larner College of Medicine, 149 Beaumont Ave, Burlington, VT, 05405, USA.
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21
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Koppers M, Özkan N, Farías GG. Complex Interactions Between Membrane-Bound Organelles, Biomolecular Condensates and the Cytoskeleton. Front Cell Dev Biol 2020; 8:618733. [PMID: 33409284 PMCID: PMC7779554 DOI: 10.3389/fcell.2020.618733] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 12/03/2020] [Indexed: 12/13/2022] Open
Abstract
Membrane-bound and membraneless organelles/biomolecular condensates ensure compartmentalization into functionally distinct units enabling proper organization of cellular processes. Membrane-bound organelles form dynamic contacts with each other to enable the exchange of molecules and to regulate organelle division and positioning in coordination with the cytoskeleton. Crosstalk between the cytoskeleton and dynamic membrane-bound organelles has more recently also been found to regulate cytoskeletal organization. Interestingly, recent work has revealed that, in addition, the cytoskeleton and membrane-bound organelles interact with cytoplasmic biomolecular condensates. The extent and relevance of these complex interactions are just beginning to emerge but may be important for cytoskeletal organization and organelle transport and remodeling. In this review, we highlight these emerging functions and emphasize the complex interplay of the cytoskeleton with these organelles. The crosstalk between membrane-bound organelles, biomolecular condensates and the cytoskeleton in highly polarized cells such as neurons could play essential roles in neuronal development, function and maintenance.
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Affiliation(s)
| | | | - Ginny G. Farías
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, Netherlands
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22
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Santinho A, Salo VT, Chorlay A, Li S, Zhou X, Omrane M, Ikonen E, Thiam AR. Membrane Curvature Catalyzes Lipid Droplet Assembly. Curr Biol 2020; 30:2481-2494.e6. [PMID: 32442467 DOI: 10.1016/j.cub.2020.04.066] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 03/24/2020] [Accepted: 04/23/2020] [Indexed: 12/20/2022]
Abstract
Lipid droplet (LD) biogenesis begins in the endoplasmic reticulum (ER) bilayer, but how the ER topology impacts this process is unclear. An early step in LD formation is nucleation, wherein free neutral lipids, mainly triacylglycerols (TGs) and sterol esters (SEs), condense into a nascent LD. How this transition occurs is poorly known. Here, we found that LDs preferably assemble at ER tubules, with higher curvature than ER sheets, independently of the LD assembly protein seipin. Indeed, the critical TG concentration required for initiating LD assembly is lower at curved versus flat membrane regions. In agreement with this finding, flat ER regions bear higher amounts of free TGs than tubular ones and present less LDs. By using an in vitro approach, we discovered that the presence of free TGs in tubules is energetically unfavorable, leading to outflow of TGs to flat membrane regions or condensation into LDs. Accordingly, in vitro LD nucleation can be achieved by the sole increase of membrane curvature. In contrast to TGs, the presence of free SEs is favored at tubules and increasing SE levels is inhibitory to the curvature-induced nucleation of TG LDs. Finally, we found that seipin is enriched at ER tubules and controls the condensation process, preventing excessive tubule-induced nucleation. The absence of seipin provokes erratic LD nucleation events determined by the abundance of ER tubules. In summary, our data indicate that membrane curvature catalyzes LD assembly.
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Affiliation(s)
- Alexandre Santinho
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, 75005 Paris, France
| | - Veijo T Salo
- Department of Anatomy and Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland; Minerva Foundation Institute for Medical Research, 00290 Helsinki, Finland
| | - Aymeric Chorlay
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, 75005 Paris, France
| | - Shiqian Li
- Department of Anatomy and Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland; Minerva Foundation Institute for Medical Research, 00290 Helsinki, Finland
| | - Xin Zhou
- Department of Anatomy and Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland; Minerva Foundation Institute for Medical Research, 00290 Helsinki, Finland
| | - Mohyeddine Omrane
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, 75005 Paris, France
| | - Elina Ikonen
- Department of Anatomy and Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland; Minerva Foundation Institute for Medical Research, 00290 Helsinki, Finland
| | - Abdou Rachid Thiam
- Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, 75005 Paris, France.
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23
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Kaul Z, Mookherjee D, Das S, Chatterjee D, Chakrabarti S, Chakrabarti O. Loss of tumor susceptibility gene 101 (TSG101) perturbs endoplasmic reticulum structure and function. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118741. [PMID: 32422153 DOI: 10.1016/j.bbamcr.2020.118741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 05/02/2020] [Accepted: 05/08/2020] [Indexed: 12/30/2022]
Abstract
Tumor susceptibility gene 101 (TSG101), an ESCRT-I protein, is implicated in multiple cellular processes and its functional depletion can lead to blocked lysosomal degradation, cell cycle arrest, demyelination and neurodegeneration. Here, we show that loss of TSG101 results in endoplasmic reticulum (ER) stress and this causes ER membrane remodelling (EMR). This correlates with an expansion of ER, increased vacuolation, altered relative distribution of the rough and smooth ER and disruption of three-way junctions. Blocked lysosomal degradation due to TSG101 depletion leads to ER stress and Ca2+ leakage from ER stores, causing destabilization of actin cytoskeleton. Inhibiting Ca2+ release from the ER by blocking ryanodine receptors (RYRs) with Dantrolene partially rescues the ER stress phenotypes. Hence, in this study we have identified the involvement of TSG101 in modulating ER stress mediated remodelling by engaging the actin cytoskeleton. This is significant because functional depletion of TSG101 effectuates ER-stress, perturbs the structure, mobility and function of the ER, all aspects closely associated with neurodegenerative diseases. SUMMARY STATEMENT: We show that tumor susceptibility gene (TSG) 101 regulates endoplasmic reticulum (ER) stress and its membrane remodelling. Loss of TSG101 perturbs structure, mobility and function of the ER as a consequence of actin destabilization.
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Affiliation(s)
- Zenia Kaul
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India; Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA..
| | - Debdatto Mookherjee
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India
| | - Subhrangshu Das
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, CN 6, Sector V, Salt Lake, Kolkata 700091, India
| | - Debmita Chatterjee
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India
| | - Saikat Chakrabarti
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, CN 6, Sector V, Salt Lake, Kolkata 700091, India
| | - Oishee Chakrabarti
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India; Homi Bhabha National Institute, India.
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24
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Vajente N, Norante R, Redolfi N, Daga A, Pizzo P, Pendin D. Microtubules Stabilization by Mutant Spastin Affects ER Morphology and Ca 2+ Handling. Front Physiol 2019; 10:1544. [PMID: 31920731 PMCID: PMC6933510 DOI: 10.3389/fphys.2019.01544] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 12/05/2019] [Indexed: 01/21/2023] Open
Abstract
The endoplasmic reticulum (ER) extends as a network of interconnected tubules and sheet-like structures in eukaryotic cells. ER tubules dynamically change their morphology and position within the cells in response to physiological stimuli and these network rearrangements depend on the microtubule (MT) cytoskeleton. Store-operated calcium entry (SOCE) relies on the repositioning of ER tubules to form specific ER-plasma membrane junctions. Indeed, the tips of polymerizing MTs are supposed to provide the anchor for ER tubules to move toward the plasma membrane, however the precise role of the cytoskeleton during SOCE has not been conclusively clarified. Here we exploit an in vivo approach involving the manipulation of MT dynamics in Drosophila melanogaster by neuronal expression of a dominant-negative variant of the MT-severing protein spastin to induce MT hyper-stabilization. We show that MT stabilization alters ER morphology, favoring an enrichment in ER sheets at the expense of tubules. Stabilizing MTs has a negative impact on the process of SOCE and results in a reduced ER Ca2+ content, affecting the flight ability of the flies. Restoring proper MT organization by administering the MT-destabilizing drug vinblastine, chronically or acutely, rescues ER morphology, SOCE and flight ability, indicating that MT dynamics impairment is responsible for all the phenotypes observed.
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Affiliation(s)
- Nicola Vajente
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Rosa Norante
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Nelly Redolfi
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Andrea Daga
- Laboratory of Molecular Biology, Scientific Institute IRCCS E. Medea, Lecco, Italy
| | - Paola Pizzo
- Department of Biomedical Sciences, University of Padua, Padua, Italy.,Neuroscience Institute-Italian National Research Council (CNR), Padua, Italy
| | - Diana Pendin
- Department of Biomedical Sciences, University of Padua, Padua, Italy.,Neuroscience Institute-Italian National Research Council (CNR), Padua, Italy
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25
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Abstract
The regulation of actin dynamics is essential for various cellular processes. Former evidence suggests a correlation between the function of non-conventional myosin motors and actin dynamics. Here we investigate the contribution of myosin 1b to actin dynamics using sliding motility assays. We observe that sliding on myosin 1b immobilized or bound to a fluid bilayer enhances actin depolymerization at the barbed end, while sliding on myosin II, although 5 times faster, has no effect. This work reveals a non-conventional myosin motor as another type of depolymerase and points to its singular interactions with the actin barbed end. Former evidence suggests a correlation between the function of non-conventional myosin motors and actin dynamics. Here authors use in vitro assays in which they observe that actin sliding on myosin 1b immobilized or bound to a fluid bilayer enhances actin depolymerization at the barbed end.
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26
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Mookherjee D, Majumder P, Mukherjee R, Chatterjee D, Kaul Z, Das S, Sougrat R, Chakrabarti S, Chakrabarti O. Cytosolic aggregates in presence of non‐translocated proteins perturb endoplasmic reticulum structure and dynamics. Traffic 2019; 20:943-960. [DOI: 10.1111/tra.12694] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 08/21/2019] [Accepted: 08/29/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Debdatto Mookherjee
- Biophysics & Structural Genomics DivisionSaha Institute of Nuclear Physics Kolkata India
| | - Priyanka Majumder
- Biophysics & Structural Genomics DivisionSaha Institute of Nuclear Physics Kolkata India
- Department of Life Sciences, School of Natural SciencesShiv Nadar University Dadri UP India
| | - Rukmini Mukherjee
- Biophysics & Structural Genomics DivisionSaha Institute of Nuclear Physics Kolkata India
- Buchmann Institute for Molecular Life Sciences Frankfurt Am Main Germany
| | - Debmita Chatterjee
- Biophysics & Structural Genomics DivisionSaha Institute of Nuclear Physics Kolkata India
| | - Zenia Kaul
- Biophysics & Structural Genomics DivisionSaha Institute of Nuclear Physics Kolkata India
- Department of Microbiology, Immunology, and Cancer BiologyUniversity of Virginia School of Medicine Charlottesville Virginia
| | - Subhrangshu Das
- Structural Biology and Bioinformatics DivisionCSIR‐Indian Institute of Chemical Biology Kolkata India
| | - Rachid Sougrat
- Imaging and Characterization Lab4700 King Abdullah University of Science and Technology Thuwal Kingdom of Saudi Arabia
| | - Saikat Chakrabarti
- Structural Biology and Bioinformatics DivisionCSIR‐Indian Institute of Chemical Biology Kolkata India
| | - Oishee Chakrabarti
- Biophysics & Structural Genomics DivisionSaha Institute of Nuclear Physics Kolkata India
- Homi Bhabha National Institute Mumbai India
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27
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Ulloa G, Hamati F, Dick A, Fitzgerald J, Mantell J, Verkade P, Collinson L, Arkill K, Larijani B, Poccia D. Lipid species affect morphology of endoplasmic reticulum: a sea urchin oocyte model of reversible manipulation. J Lipid Res 2019; 60:1880-1891. [PMID: 31548365 PMCID: PMC6824487 DOI: 10.1194/jlr.ra119000210] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 09/11/2019] [Indexed: 12/22/2022] Open
Abstract
The ER is a large multifunctional organelle of eukaryotic cells. Malfunction of the ER in various disease states, such as atherosclerosis, diabetes, cancer, Alzheimer’s and Parkinson’s and amyotrophic lateral sclerosis, often correlates with alterations in its morphology. The ER exhibits regionally variable membrane morphology that includes, at the extremes, large relatively flat surfaces and interconnected tubular structures highly curved in cross-section. ER morphology is controlled by shaping proteins that associate with membrane lipids. To investigate the role of these lipids, we developed a sea urchin oocyte model, a relatively quiescent cell in which the ER consists mostly of tubules. We altered levels of endogenous diacylglycerol (DAG), phosphatidylethanolamine (PtdEth), and phosphatidylcholine by microinjection of enzymes or lipid delivery by liposomes and evaluated shape changes with 2D and 3D confocal imaging and 3D electron microscopy. Decreases and increases in the levels of lipids such as DAG or PtdEth characterized by negative spontaneous curvature correlated with conversion to sheet structures or tubules, respectively. The effects of endogenous alterations of DAG were reversible upon exogenous delivery of lipids of negative spontaneous curvature. These data suggest that proteins require threshold amounts of such lipids and that localized deficiencies of the lipids could contribute to alterations of ER morphology. The oocyte modeling system should be beneficial to studies directed at understanding requirements of lipid species in interactions leading to alterations of organelle shaping.
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Affiliation(s)
| | - Fadi Hamati
- Department of Biology, Amherst College, Amherst, MA
| | | | | | - Judith Mantell
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Paul Verkade
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | | | - Kenton Arkill
- School of Medicine, Faculty of Medicine and Health Sciences, University of Nottingham Medical School, Nottingham, United Kingdom
| | - Banafshe Larijani
- Centre for Therapeutic Innovation, Cell Biophysics Laboratory, Department of Pharmacy and Pharmacology and Department of Physics, University of Bath, Claverton Down, Bath, United Kingdom, and Cell Biophysics Laboratory, Ikerbasque, Basque Foundation for Science, Research Centre for Experimental Marine Biology and Biotechnology (PiE) and Biophysics Institute (UPV/EHU, CSIC), University of the Basque Country, Leioa, Spain
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28
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Pain C, Kriechbaumer V, Kittelmann M, Hawes C, Fricker M. Quantitative analysis of plant ER architecture and dynamics. Nat Commun 2019; 10:984. [PMID: 30816109 PMCID: PMC6395764 DOI: 10.1038/s41467-019-08893-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 02/05/2019] [Indexed: 02/06/2023] Open
Abstract
The endoplasmic reticulum (ER) is a highly dynamic polygonal membrane network composed of interconnected tubules and sheets (cisternae) that forms the first compartment in the secretory pathway involved in protein translocation, folding, glycosylation, quality control, lipid synthesis, calcium signalling, and metabolon formation. Despite its central role in this plethora of biosynthetic, metabolic and physiological processes, there is little quantitative information on ER structure, morphology or dynamics. Here we describe a software package (AnalyzER) to automatically extract ER tubules and cisternae from multi-dimensional fluorescence images of plant ER. The structure, topology, protein-localisation patterns, and dynamics are automatically quantified using spatial, intensity and graph-theoretic metrics. We validate the method against manually-traced ground-truth networks, and calibrate the sub-resolution width estimates against ER profiles identified in serial block-face SEM images. We apply the approach to quantify the effects on ER morphology of drug treatments, abiotic stress and over-expression of ER tubule-shaping and cisternal-modifying proteins.
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Affiliation(s)
- Charlotte Pain
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Verena Kriechbaumer
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Maike Kittelmann
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Chris Hawes
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Mark Fricker
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK.
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29
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Flynn CM, Broz K, Jonkers W, Schmidt-Dannert C, Kistler HC. Expression of the Fusarium graminearum terpenome and involvement of the endoplasmic reticulum-derived toxisome. Fungal Genet Biol 2019; 124:78-87. [PMID: 30664933 DOI: 10.1016/j.fgb.2019.01.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 11/29/2018] [Accepted: 01/14/2019] [Indexed: 12/26/2022]
Abstract
The sesquiterpenoid deoxynivalenol (DON) is an important trichothecene mycotoxin produced by the cereal pathogen Fusarium graminearum. DON is synthesized in specialized subcellular structures called toxisomes. The first step in DON synthesis is catalyzed by the sesquiterpene synthase (STS), Tri5 (trichodiene synthase), resulting in the cyclization of farnesyl diphosphate (FPP) to produce the sesquiterpene trichodiene. Tri5 is one of eight putative STSs in the F. graminearum genome. To better understand the F. graminearum terpenome, the volatile and soluble fractions of fungal cultures were sampled. Stringent regulation of sesquiterpene accumulation was observed. When grown in trichothecene induction medium, the fungus produces trichothecenes as well as several volatile non-trichothecene related sesquiterpenes, whereas no volatile terpenes were detected when grown in non-inducing medium. Surprisingly, a Δtri5 deletion strain grown in inducing conditions not only ceased accumulation of trichothecenes, but also failed to produce the non-trichothecene related sesquiterpenes. To test whether Tri5 from F. graminearum may be a promiscuous STS directly producing all observed sesquiterpenes, Tri5 was cloned and expressed in E. coli and shown to produce primarily trichodiene in addition to minor, related cyclization products. Therefore, while Tri5 expression in F. graminearum is necessary for non-trichothecene sesquiterpene biosynthesis, direct catalysis by Tri5 does not explain the sesquiterpene deficient phenotype observed in the Δtri5 strain. To test whether Tri5 protein, separate from its enzymatic activity, may be required for non-trichothecene synthesis, the Tri5 locus was replaced with an enzymatically inactive, but structurally unaffected tri5N225D S229T allele. This allele restores non-trichothecene synthesis but not trichothecene synthesis. The tri5N225D S229T allele also restores toxisome structure which is lacking in the Δtri5 deletion strain. Our results indicate that the Tri5 protein, but not its enzymatic activity, is also required for the synthesis of non-trichothecene related sesquiterpenes and the formation of toxisomes. Toxisomes thus not only may be important for DON synthesis, but also for the synthesis of other sesquiterpene mycotoxins such as culmorin by F. graminearum.
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Affiliation(s)
- Christopher M Flynn
- University of Minnesota, Department of Biochemistry, Molecular Biology, and Biophysics, Saint Paul, MN, USA
| | - Karen Broz
- USDA ARS Cereal Disease Laboratory, Saint Paul, MN, USA
| | | | - Claudia Schmidt-Dannert
- University of Minnesota, Department of Biochemistry, Molecular Biology, and Biophysics, Saint Paul, MN, USA
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30
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Capmany A, Yoshimura A, Kerdous R, Caorsi V, Lescure A, Nery ED, Coudrier E, Goud B, Schauer K. MYO1C stabilizes actin and facilitates arrival of transport carriers at the Golgi apparatus. J Cell Sci 2019; 132:jcs.225029. [DOI: 10.1242/jcs.225029] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 03/01/2019] [Indexed: 12/22/2022] Open
Abstract
We aim to identify the myosin motor proteins that control trafficking at the Golgi apparatus. In addition to the known Golgi-associated myosins MYO6, MYO18A and MYH9 (myosin IIA), we identify MYO1C as a novel player at the Golgi. We demonstrate that depletion of MYO1C induces Golgi apparatus fragmentation and decompaction. MYO1C accumulates at dynamic structures around the Golgi apparatus that colocalize with Golgi-associated actin dots. MYO1C depletion leads to loss of cellular F-actin, and Golgi apparatus decompaction is also observed after the inhibition or loss of the Arp2/3 complex. We show that the functional consequences of MYO1C depletion is a delay in the arrival of incoming transport carriers, both from the anterograde and retrograde routes. We propose that MYO1C stabilizes actin at the Golgi apparatus facilitating the arrival of incoming transport carriers at the Golgi.
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Affiliation(s)
- Anahi Capmany
- Institut Curie, PSL Research University, Molecular Mechanisms of Intracellular Transport group, 75248 Paris Cedex 05, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche144, 75005 Paris, France
| | - Azumi Yoshimura
- Institut Curie, PSL Research University, Molecular Mechanisms of Intracellular Transport group, 75248 Paris Cedex 05, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche144, 75005 Paris, France
| | - Rachid Kerdous
- Institut Curie, PSL Research University, Molecular Mechanisms of Intracellular Transport group, 75248 Paris Cedex 05, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche144, 75005 Paris, France
| | | | - Aurianne Lescure
- Institut Curie, PSL Research University, Molecular Mechanisms of Intracellular Transport group, 75248 Paris Cedex 05, France
- Department of Translational Research, BioPhenics High-Content Screening Laboratory, Cell and Tissue Imaging Facility (PICT-IBiSA), Paris, France
| | - Elaine Del Nery
- Institut Curie, PSL Research University, Molecular Mechanisms of Intracellular Transport group, 75248 Paris Cedex 05, France
- Department of Translational Research, BioPhenics High-Content Screening Laboratory, Cell and Tissue Imaging Facility (PICT-IBiSA), Paris, France
| | - Evelyne Coudrier
- Institut Curie, PSL Research University, Molecular Mechanisms of Intracellular Transport group, 75248 Paris Cedex 05, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche144, 75005 Paris, France
| | - Bruno Goud
- Institut Curie, PSL Research University, Molecular Mechanisms of Intracellular Transport group, 75248 Paris Cedex 05, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche144, 75005 Paris, France
| | - Kristine Schauer
- Institut Curie, PSL Research University, Molecular Mechanisms of Intracellular Transport group, 75248 Paris Cedex 05, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche144, 75005 Paris, France
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31
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Grebenkov DS, Krapf D. Steady-state reaction rate of diffusion-controlled reactions in sheets. J Chem Phys 2018; 149:064117. [DOI: 10.1063/1.5041074] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Denis S. Grebenkov
- Laboratoire de Physique de la Matière Condensée (UMR 7643), CNRS–Ecole Polytechnique, University Paris-Saclay, 91128 Palaiseau, France
| | - Diego Krapf
- Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80523, USA
- School of Biomedical Engineering, Colorado State University, Fort Collins, Colorado 80523, USA
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32
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Nevzorov I, Sidorenko E, Wang W, Zhao H, Vartiainen MK. Myosin-1C uses a novel phosphoinositide-dependent pathway for nuclear localization. EMBO Rep 2018; 19:290-304. [PMID: 29330316 PMCID: PMC5797967 DOI: 10.15252/embr.201744296] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 12/05/2017] [Accepted: 12/11/2017] [Indexed: 01/07/2023] Open
Abstract
Accurate control of macromolecule transport between nucleus and cytoplasm underlines several essential biological processes, including gene expression. According to the canonical model, nuclear import of soluble proteins is based on nuclear localization signals and transport factors. We challenge this view by showing that nuclear localization of the actin-dependent motor protein Myosin-1C (Myo1C) resembles the diffusion-retention mechanism utilized by inner nuclear membrane proteins. We show that Myo1C constantly shuttles in and out of the nucleus and that its nuclear localization does not require soluble factors, but is dependent on phosphoinositide binding. Nuclear import of Myo1C is preceded by its interaction with the endoplasmic reticulum, and phosphoinositide binding is specifically required for nuclear import, but not nuclear retention, of Myo1C. Our results therefore demonstrate, for the first time, that membrane association and binding to nuclear partners is sufficient to drive nuclear localization of also soluble proteins, opening new perspectives to evolution of cellular protein sorting mechanisms.
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Affiliation(s)
- Ilja Nevzorov
- Program in Cell and Molecular Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Ekaterina Sidorenko
- Program in Cell and Molecular Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Weihuan Wang
- Program in Cell and Molecular Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
- College of Life Sciences, Northwest A&F University, Yangling, Shanxi, China
| | - Hongxia Zhao
- Program in Cell and Molecular Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Maria K Vartiainen
- Program in Cell and Molecular Biology, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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33
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Hanna H, Denzi A, Liberti M, André FM, Mir LM. Electropermeabilization of Inner and Outer Cell Membranes with Microsecond Pulsed Electric Fields: Quantitative Study with Calcium Ions. Sci Rep 2017; 7:13079. [PMID: 29026094 PMCID: PMC5638809 DOI: 10.1038/s41598-017-12960-w] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 09/15/2017] [Indexed: 12/18/2022] Open
Abstract
Microsecond pulsed electric fields (μsPEF) permeabilize the plasma membrane (PM) and are widely used in research, medicine and biotechnology. For internal membranes permeabilization, nanosecond pulsed electric fields (nsPEF) are applied but this technology is complex to use. Here we report that the endoplasmic reticulum (ER) membrane can also be electropermeabilized by one 100 µs pulse without affecting the cell viability. Indeed, using Ca2+ as a permeabilization marker, we observed cytosolic Ca2+ peaks in two different cell types after one 100 µs pulse in a medium without Ca2+. Thapsigargin abolished these Ca2+ peaks demonstrating that the calcium is released from the ER. Moreover, IP3R and RyR inhibitors did not modify these peaks showing that they are due to the electropermeabilization of the ER membrane and not to ER Ca2+ channels activation. Finally, the comparison of the two cell types suggests that the PM and the ER permeabilization thresholds are affected by the sizes of the cell and the ER. In conclusion, this study demonstrates that µsPEF, which are easier to control than nsPEF, can permeabilize internal membranes. Besides, μsPEF interaction with either the PM or ER, can be an efficient tool to modulate the cytosolic calcium concentration and study Ca2+ roles in cell physiology.
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Affiliation(s)
- Hanna Hanna
- Vectorology and Anticancer Therapies, UMR 8203, CNRS, Univ. Paris-Sud, Gustave Roussy, Université Paris-Saclay, 94 805, Villejuif, France
| | - Agnese Denzi
- Department of Information Engineering, Electronics and Telecommunication (DIET), University of Rome "La Sapienza", Rome, 00184, Italy
| | - Micaela Liberti
- Department of Information Engineering, Electronics and Telecommunication (DIET), University of Rome "La Sapienza", Rome, 00184, Italy
| | - Franck M André
- Vectorology and Anticancer Therapies, UMR 8203, CNRS, Univ. Paris-Sud, Gustave Roussy, Université Paris-Saclay, 94 805, Villejuif, France
| | - Lluis M Mir
- Vectorology and Anticancer Therapies, UMR 8203, CNRS, Univ. Paris-Sud, Gustave Roussy, Université Paris-Saclay, 94 805, Villejuif, France.
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34
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Kee AJ, Bryce NS, Yang L, Polishchuk E, Schevzov G, Weigert R, Polishchuk R, Gunning PW, Hardeman EC. ER/Golgi trafficking is facilitated by unbranched actin filaments containing Tpm4.2. Cytoskeleton (Hoboken) 2017; 74:379-389. [PMID: 28834398 DOI: 10.1002/cm.21405] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 07/31/2017] [Accepted: 08/16/2017] [Indexed: 01/14/2023]
Abstract
We have identified novel actin filaments defined by tropomyosin Tpm4.2 at the ER. EM analysis of mouse embryo fibroblasts (MEFs) isolated from mice expressing a mutant Tpm4.2 (Tpm4Plt53/Plt53 ), incapable of incorporating into actin filaments, revealed swollen ER structures compared with wild-type (WT) MEFs (Tpm4+/+ ). ER-to-Golgi, but not Golgi-to-ER trafficking was altered in the Tpm4Plt53/Plt53 MEFs following the transfection of the temperature sensitive ER-associated ts045-VSVg construct. Exogenous Tpm4.2 was able to rescue the ER-to-Golgi trafficking defect in the Tpm4Plt53/Plt53 cells. The treatment of WT MEFs with the myosin II inhibitor, blebbistatin, blocked the Tpm4.2-dependent ER-to-Golgi trafficking. The lack of an effect on ER-to-Golgi trafficking following treatment of MEFs with CK666 indicates that branched Arp2/3-containing actin filaments are not involved in anterograde vesicle trafficking. We propose that unbranched, Tpm4.2-containing filaments have an important role in maintaining ER/Golgi structure and that these structures, in conjunction with myosin II motors, mediate ER-to-Golgi trafficking.
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Affiliation(s)
- Anthony J Kee
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Nicole S Bryce
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Lingyan Yang
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Elena Polishchuk
- Telethon Institute of Genetics and Medicine, Naples 80131, Italy
| | - Galina Schevzov
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Roberto Weigert
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892
| | - Roman Polishchuk
- Telethon Institute of Genetics and Medicine, Naples 80131, Italy
| | - Peter W Gunning
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Edna C Hardeman
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
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35
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Gupta P, Martin R, Knölker HJ, Nihalani D, Kumar Sinha D. Myosin-1 inhibition by PClP affects membrane shape, cortical actin distribution and lipid droplet dynamics in early Zebrafish embryos. PLoS One 2017; 12:e0180301. [PMID: 28678859 PMCID: PMC5498032 DOI: 10.1371/journal.pone.0180301] [Citation(s) in RCA: 11] [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: 01/12/2017] [Accepted: 06/13/2017] [Indexed: 12/22/2022] Open
Abstract
Myosin-1 (Myo1) represents a mechanical link between the membrane and actin-cytoskeleton in animal cells. We have studied the effect of Myo1 inhibitor PClP in 1-8 cell Zebrafish embryos. Our results indicate a unique involvement of Myo1 in early development of Zebrafish embryos. Inhibition of Myo1 (by PClP) and Myo2 (by Blebbistatin) lead to arrest in cell division. While Myo1 isoforms appears to be important for both the formation and the maintenance of cleavage furrows, Myo2 is required only for the formation of furrows. We found that the blastodisc of the embryo, which contains a thick actin cortex (~13 μm), is loaded with cortical Myo1. Myo1 appears to be crucial for maintaining the blastodisc morphology and the actin cortex thickness. In addition to cell division and furrow formation, inhibition of Myo1 has a drastic effect on the dynamics and distribution of lipid droplets (LDs) in the blastodisc near the cleavage furrow. All these results above are effects of Myo1 inhibition exclusively; Myo2 inhibition by blebbistatin does not show such phenotypes. Therefore, our results demonstrate a potential role for Myo1 in the maintenance and formation of furrow, blastodisc morphology, cell-division and LD organization within the blastodisc during early embryogenesis.
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MESH Headings
- Actin Cytoskeleton/drug effects
- Actin Cytoskeleton/metabolism
- Actins/genetics
- Actins/metabolism
- Animals
- Blastomeres/cytology
- Blastomeres/metabolism
- Blastomeres/ultrastructure
- Blotting, Western
- Cell Division/drug effects
- Cell Division/genetics
- Cell Membrane/metabolism
- Embryo, Nonmammalian/embryology
- Embryo, Nonmammalian/metabolism
- Embryo, Nonmammalian/ultrastructure
- Gene Expression Regulation, Developmental
- Heterocyclic Compounds, 4 or More Rings/pharmacology
- Hydrocarbons, Chlorinated/pharmacology
- Lipid Droplets/metabolism
- Microscopy, Electron, Scanning
- Microscopy, Fluorescence
- Myosin Heavy Chains/antagonists & inhibitors
- Myosin Heavy Chains/genetics
- Myosin Heavy Chains/metabolism
- Pyrroles/pharmacology
- Reverse Transcriptase Polymerase Chain Reaction
- Zebrafish/embryology
- Zebrafish/genetics
- Zebrafish/metabolism
- Zebrafish Proteins/antagonists & inhibitors
- Zebrafish Proteins/genetics
- Zebrafish Proteins/metabolism
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Affiliation(s)
| | - René Martin
- Department Chemie, TU Dresden, Dresden, Germany
| | | | - Deepak Nihalani
- Dept. Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America
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36
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Lopez-Crisosto C, Pennanen C, Vasquez-Trincado C, Morales PE, Bravo-Sagua R, Quest AFG, Chiong M, Lavandero S. Sarcoplasmic reticulum-mitochondria communication in cardiovascular pathophysiology. Nat Rev Cardiol 2017; 14:342-360. [PMID: 28275246 DOI: 10.1038/nrcardio.2017.23] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Repetitive, calcium-mediated contractile activity renders cardiomyocytes critically dependent on a sustained energy supply and adequate calcium buffering, both of which are provided by mitochondria. Moreover, in vascular smooth muscle cells, mitochondrial metabolism modulates cell growth and proliferation, whereas cytosolic calcium levels regulate the arterial vascular tone. Physical and functional communication between mitochondria and sarco/endoplasmic reticulum and balanced mitochondrial dynamics seem to have a critical role for optimal calcium transfer to mitochondria, which is crucial in calcium homeostasis and mitochondrial metabolism in both types of muscle cells. Moreover, mitochondrial dysfunction has been associated with myocardial damage and dysregulation of vascular smooth muscle proliferation. Therefore, sarco/endoplasmic reticulum-mitochondria coupling and mitochondrial dynamics are now viewed as relevant factors in the pathogenesis of cardiac and vascular diseases, including coronary artery disease, heart failure, and pulmonary arterial hypertension. In this Review, we summarize the evidence related to the role of sarco/endoplasmic reticulum-mitochondria communication in cardiac and vascular muscle physiology, with a focus on how perturbations contribute to the pathogenesis of cardiovascular disorders.
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Affiliation(s)
- Camila Lopez-Crisosto
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile
| | - Christian Pennanen
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile
| | - Cesar Vasquez-Trincado
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile
| | - Pablo E Morales
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile
| | - Roberto Bravo-Sagua
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile.,Instituto de Nutricion y Tecnologia de los Alimentos (INTA), Universidad de Chile, Avenida El Líbano 5524, Santiago 7830490, Chile
| | - Andrew F G Quest
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile.,Centro de Estudios Moleculares de la Celula (CEMC), Instituto de Ciencias Biomedicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago 8380453, Chile
| | - Mario Chiong
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile
| | - Sergio Lavandero
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile.,Centro de Estudios Moleculares de la Celula (CEMC), Instituto de Ciencias Biomedicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago 8380453, Chile.,Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, Dallas, Texas 75235, USA
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37
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Rämö O, Kumar D, Gucciardo E, Joensuu M, Saarekas M, Vihinen H, Belevich I, Smolander OP, Qian K, Auvinen P, Jokitalo E. NOGO-A/RTN4A and NOGO-B/RTN4B are simultaneously expressed in epithelial, fibroblast and neuronal cells and maintain ER morphology. Sci Rep 2016; 6:35969. [PMID: 27786289 PMCID: PMC5081510 DOI: 10.1038/srep35969] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 10/07/2016] [Indexed: 02/08/2023] Open
Abstract
Reticulons (RTNs) are a large family of membrane associated proteins with various functions. NOGO-A/RTN4A has a well-known function in limiting neurite outgrowth and restricting the plasticity of the mammalian central nervous system. On the other hand, Reticulon 4 proteins were shown to be involved in forming and maintaining endoplasmic reticulum (ER) tubules. Using comparative transcriptome analysis and qPCR, we show here that NOGO-B/RTN4B and NOGO-A/RTN4A are simultaneously expressed in cultured epithelial, fibroblast and neuronal cells. Electron tomography combined with immunolabelling reveal that both isoforms localize preferably to curved membranes on ER tubules and sheet edges. Morphological analysis of cells with manipulated levels of NOGO-B/RTN4B revealed that it is required for maintenance of normal ER shape; over-expression changes the sheet/tubule balance strongly towards tubules and causes the deformation of the cell shape while depletion of the protein induces formation of large peripheral ER sheets.
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Affiliation(s)
- Olli Rämö
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Darshan Kumar
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Erika Gucciardo
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Merja Joensuu
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Maiju Saarekas
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Helena Vihinen
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Helsinki, Finland.,Electron Microscopy Unit, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Ilya Belevich
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Helsinki, Finland.,Electron Microscopy Unit, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Olli-Pekka Smolander
- DNA Sequencing and Genomics Laboratory, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Kui Qian
- DNA Sequencing and Genomics Laboratory, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Petri Auvinen
- DNA Sequencing and Genomics Laboratory, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Eija Jokitalo
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, Helsinki, Finland.,Electron Microscopy Unit, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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38
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Abstract
Myosin-I molecular motors are proposed to play various cellular roles related to membrane dynamics and trafficking. In this Cell Science at a Glance article and the accompanying poster, we review and illustrate the proposed cellular functions of metazoan myosin-I molecular motors by examining the structural, biochemical, mechanical and cell biological evidence for their proposed molecular roles. We highlight evidence for the roles of myosin-I isoforms in regulating membrane tension and actin architecture, powering plasma membrane and organelle deformation, participating in membrane trafficking, and functioning as a tension-sensitive dock or tether. Collectively, myosin-I motors have been implicated in increasingly complex cellular phenomena, yet how a single isoform accomplishes multiple types of molecular functions is still an active area of investigation. To fully understand the underlying physiology, it is now essential to piece together different approaches of biological investigation. This article will appeal to investigators who study immunology, metabolic diseases, endosomal trafficking, cell motility, cancer and kidney disease, and to those who are interested in how cellular membranes are coupled to the underlying actin cytoskeleton in a variety of different applications.
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Affiliation(s)
- Betsy B McIntosh
- Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6085, USA
| | - E Michael Ostap
- Pennsylvania Muscle Institute and Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6085, USA
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39
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Endoplasmic Reticulum: The Favorite Intracellular Niche for Viral Replication and Assembly. Viruses 2016; 8:v8060160. [PMID: 27338443 PMCID: PMC4926180 DOI: 10.3390/v8060160] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 05/23/2016] [Accepted: 05/26/2016] [Indexed: 02/07/2023] Open
Abstract
The endoplasmic reticulum (ER) is the largest intracellular organelle. It forms a complex network of continuous sheets and tubules, extending from the nuclear envelope (NE) to the plasma membrane. This network is frequently perturbed by positive-strand RNA viruses utilizing the ER to create membranous replication factories (RFs), where amplification of their genomes occurs. In addition, many enveloped viruses assemble progeny virions in association with ER membranes, and viruses replicating in the nucleus need to overcome the NE barrier, requiring transient changes of the NE morphology. This review first summarizes some key aspects of ER morphology and then focuses on the exploitation of the ER by viruses for the sake of promoting the different steps of their replication cycles.
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40
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Abstract
Exocytosis at the inner hair cell ribbon synapse is achieved through the functional coupling between calcium channels and glutamate-filled synaptic vesicles. Using membrane capacitance measurements, we investigated whether the actin network regulates the exocytosis of synaptic vesicles at the mouse auditory hair cell. Our results suggest that actin network disruption increases exocytosis and that actin filaments may spatially organize a subfraction of synaptic vesicles with respect to the calcium channels. Significance statement: Inner hair cells (IHCs), the auditory sensory cells of the cochlea, release glutamate onto the afferent auditory nerve fibers to encode sound stimulation. To achieve this task, the IHC relies on the recruitment of glutamate-filled vesicles that can be located in close vicinity to the calcium channels or more remotely from them. The molecular determinants responsible for organizing these vesicle pools are not fully identified. Using pharmacological tools in combination with membrane capacitance measurements, we show that actin filament disruption increases exocytosis in IHCs and that actin filaments most likely position a fraction of vesicles away from the calcium channels.
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41
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Plácido AI, Pereira CMF, Correira SC, Carvalho C, Oliveira CR, Moreira PI. Phosphatase 2A Inhibition Affects Endoplasmic Reticulum and Mitochondria Homeostasis Via Cytoskeletal Alterations in Brain Endothelial Cells. Mol Neurobiol 2016; 54:154-168. [DOI: 10.1007/s12035-015-9640-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 12/15/2015] [Indexed: 12/30/2022]
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42
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Belevich I, Joensuu M, Kumar D, Vihinen H, Jokitalo E. Microscopy Image Browser: A Platform for Segmentation and Analysis of Multidimensional Datasets. PLoS Biol 2016; 14:e1002340. [PMID: 26727152 PMCID: PMC4699692 DOI: 10.1371/journal.pbio.1002340] [Citation(s) in RCA: 227] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Understanding the structure-function relationship of cells and organelles in their natural context requires multidimensional imaging. As techniques for multimodal 3-D imaging have become more accessible, effective processing, visualization, and analysis of large datasets are posing a bottleneck for the workflow. Here, we present a new software package for high-performance segmentation and image processing of multidimensional datasets that improves and facilitates the full utilization and quantitative analysis of acquired data, which is freely available from a dedicated website. The open-source environment enables modification and insertion of new plug-ins to customize the program for specific needs. We provide practical examples of program features used for processing, segmentation and analysis of light and electron microscopy datasets, and detailed tutorials to enable users to rapidly and thoroughly learn how to use the program.
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Affiliation(s)
- Ilya Belevich
- Electron Microscopy Unit, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Merja Joensuu
- Electron Microscopy Unit, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Darshan Kumar
- Electron Microscopy Unit, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Helena Vihinen
- Electron Microscopy Unit, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Eija Jokitalo
- Electron Microscopy Unit, Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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43
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ER sheet–tubule balance is regulated by an array of actin filaments and microtubules. Exp Cell Res 2015; 337:170-8. [DOI: 10.1016/j.yexcr.2015.04.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 04/13/2015] [Indexed: 12/28/2022]
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44
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Gurel PS, Hatch AL, Higgs HN. Connecting the cytoskeleton to the endoplasmic reticulum and Golgi. Curr Biol 2015; 24:R660-R672. [PMID: 25050967 DOI: 10.1016/j.cub.2014.05.033] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A tendency in cell biology is to divide and conquer. For example, decades of painstaking work have led to an understanding of endoplasmic reticulum (ER) and Golgi structure, dynamics, and transport. In parallel, cytoskeletal researchers have revealed a fantastic diversity of structure and cellular function in both actin and microtubules. Increasingly, these areas overlap, necessitating an understanding of both organelle and cytoskeletal biology. This review addresses connections between the actin/microtubule cytoskeletons and organelles in animal cells, focusing on three key areas: ER structure and function; ER-to-Golgi transport; and Golgi structure and function. Making these connections has been challenging for several reasons: the small sizes and dynamic characteristics of some components; the fact that organelle-specific cytoskeletal elements can easily be obscured by more abundant cytoskeletal structures; and the difficulties in imaging membranes and cytoskeleton simultaneously, especially at the ultrastructural level. One major concept is that the cytoskeleton is frequently used to generate force for membrane movement, with two potential consequences: translocation of the organelle, or deformation of the organelle membrane. While initially discussing issues common to metazoan cells in general, we subsequently highlight specific features of neurons, since these highly polarized cells present unique challenges for organellar distribution and dynamics.
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Affiliation(s)
- Pinar S Gurel
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover NH 03755, USA
| | - Anna L Hatch
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover NH 03755, USA
| | - Henry N Higgs
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover NH 03755, USA.
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45
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Wang ZH, Rabouille C, Geisbrecht ER. Loss of a Clueless-dGRASP complex results in ER stress and blocks Integrin exit from the perinuclear endoplasmic reticulum in Drosophila larval muscle. Biol Open 2015; 4:636-48. [PMID: 25862246 PMCID: PMC4434815 DOI: 10.1242/bio.201511551] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Drosophila Clueless (Clu) and its conserved orthologs are known for their role in the prevention of mitochondrial clustering. Here, we uncover a new role for Clu in the delivery of integrin subunits in muscle tissue. In clu mutants, αPS2 integrin, but not βPS integrin, abnormally accumulates in a perinuclear endoplasmic reticulum (ER) subdomain, a site that mirrors the endogenous localization of Clu. Loss of components essential for mitochondrial distribution do not phenocopy the clu mutant αPS2 phenotype. Conversely, RNAi knockdown of the DrosophilaGolgi reassembly and stacking protein GRASP55/65 (dGRASP) recapitulates clu defects, including the abnormal accumulation of αPS2 and larval locomotor activity. Both Clu and dGRASP proteins physically interact and loss of Clu displaces dGRASP from ER exit sites, suggesting that Clu cooperates with dGRASP for the exit of αPS2 from a perinuclear subdomain in the ER. We also found that Clu and dGRASP loss of function leads to ER stress and that the stability of the ER exit site protein Sec16 is severely compromised in the clu mutants, thus explaining the ER accumulation of αPS2. Remarkably, exposure of clu RNAi larvae to chemical chaperones restores both αPS2 delivery and functional ER exit sites. We propose that Clu together with dGRASP prevents ER stress and therefore maintains Sec16 stability essential for the functional organization of perinuclear early secretory pathway. This, in turn, is essential for integrin subunit αPS2 ER exit in Drosophila larval myofibers.
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Affiliation(s)
- Zong-Heng Wang
- Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri, Kansas City, MO 64110, USA
| | - Catherine Rabouille
- Hubrecht Institute-KNAW & University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands The Department of Cell Biology, UMC Utrecht, 3584 CX Utrecht, The Netherlands
| | - Erika R Geisbrecht
- Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri, Kansas City, MO 64110, USA Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506, USA
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46
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Starborg T, Kadler KE. Serial block face-scanning electron microscopy: A tool for studying embryonic development at the cell-matrix interface. ACTA ACUST UNITED AC 2015; 105:9-18. [DOI: 10.1002/bdrc.21087] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 02/18/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Tobias Starborg
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences; University of Manchester, Michael Smith Building; Oxford Road Manchester United Kingdom
| | - Karl E. Kadler
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences; University of Manchester, Michael Smith Building; Oxford Road Manchester United Kingdom
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47
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Kremer A, Lippens S, Bartunkova S, Asselbergh B, Blanpain C, Fendrych M, Goossens A, Holt M, Janssens S, Krols M, Larsimont JC, Mc Guire C, Nowack MK, Saelens X, Schertel A, Schepens B, Slezak M, Timmerman V, Theunis C, VAN Brempt R, Visser Y, Guérin CJ. Developing 3D SEM in a broad biological context. J Microsc 2015; 259:80-96. [PMID: 25623622 PMCID: PMC4670703 DOI: 10.1111/jmi.12211] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 11/28/2014] [Indexed: 12/25/2022]
Abstract
When electron microscopy (EM) was introduced in the 1930s it gave scientists their first look into the nanoworld of cells. Over the last 80 years EM has vastly increased our understanding of the complex cellular structures that underlie the diverse functions that cells need to maintain life. One drawback that has been difficult to overcome was the inherent lack of volume information, mainly due to the limit on the thickness of sections that could be viewed in a transmission electron microscope (TEM). For many years scientists struggled to achieve three-dimensional (3D) EM using serial section reconstructions, TEM tomography, and scanning EM (SEM) techniques such as freeze-fracture. Although each technique yielded some special information, they required a significant amount of time and specialist expertise to obtain even a very small 3D EM dataset. Almost 20 years ago scientists began to exploit SEMs to image blocks of embedded tissues and perform serial sectioning of these tissues inside the SEM chamber. Using first focused ion beams (FIB) and subsequently robotic ultramicrotomes (serial block-face, SBF-SEM) microscopists were able to collect large volumes of 3D EM information at resolutions that could address many important biological questions, and do so in an efficient manner. We present here some examples of 3D EM taken from the many diverse specimens that have been imaged in our core facility. We propose that the next major step forward will be to efficiently correlate functional information obtained using light microscopy (LM) with 3D EM datasets to more completely investigate the important links between cell structures and their functions.
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Affiliation(s)
- A Kremer
- VIB Bio Imaging Core, Gent, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - S Lippens
- VIB Bio Imaging Core, Gent, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - S Bartunkova
- VIB Bio Imaging Core, Gent, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - B Asselbergh
- VIB Department of Molecular Genetics, Antwerp University, Antwerpen 2020, Belgium
| | - C Blanpain
- IRIBHM, Université Libre de Bruxelles, Brussels, B-1070, Belgium
| | - M Fendrych
- Department of Plant Systems Biology, VIB, Ghent, 9052, Belgium.,Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium.,Institute of Science and Technology (IST) Austria, Klosterneuburg, 3400, Austria
| | - A Goossens
- Department of Plant Systems Biology, VIB, Ghent, 9052, Belgium.,Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
| | - M Holt
- Center for the Biology of Disease, VIB, Leuven, Belgium.,Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
| | - S Janssens
- Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Department of Respiratory Medicine, Ghent University, Ghent, Belgium.,GROUP-ID Consortium, Ghent University and University Hospital, Ghent, Belgium
| | - M Krols
- Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,VIB Department of Molecular Genetics, Antwerp University, Antwerpen 2020, Belgium
| | - J-C Larsimont
- IRIBHM, Université Libre de Bruxelles, Brussels, B-1070, Belgium
| | - C Mc Guire
- Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - M K Nowack
- Department of Plant Systems Biology, VIB, Ghent, 9052, Belgium.,Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium
| | - X Saelens
- Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - A Schertel
- Carl Zeiss Microscopy, GmbH, Oberkochen, Germany
| | - B Schepens
- Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - M Slezak
- Center for the Biology of Disease, VIB, Leuven, Belgium
| | - V Timmerman
- VIB Department of Molecular Genetics, Antwerp University, Antwerpen 2020, Belgium
| | - C Theunis
- Department of Intensive Care, Leiden University Medical Center, Leiden, The Netherlands.,Johnson and Johnson Pharmaceutical Research and Development, Beerse, Belgium
| | - R VAN Brempt
- Department of Intensive Care, Leiden University Medical Center, Leiden, The Netherlands.,Johnson and Johnson Pharmaceutical Research and Development, Beerse, Belgium
| | - Y Visser
- Department of Intensive Care, Leiden University Medical Center, Leiden, The Netherlands.,Johnson and Johnson Pharmaceutical Research and Development, Beerse, Belgium
| | - C J Guérin
- VIB Bio Imaging Core, Gent, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Inflammation Research Center, VIB, Technologiepark 927, Gent, B-9052, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
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48
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Westrate LM, Lee JE, Prinz WA, Voeltz GK. Form follows function: the importance of endoplasmic reticulum shape. Annu Rev Biochem 2015; 84:791-811. [PMID: 25580528 DOI: 10.1146/annurev-biochem-072711-163501] [Citation(s) in RCA: 253] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The endoplasmic reticulum (ER) has a remarkably complex structure, composed of a single bilayer that forms the nuclear envelope, along with a network of sheets and dynamic tubules. Our understanding of the biological significance of the complex architecture of the ER has improved dramatically in the last few years. The identification of proteins and forces required for maintaining ER shape, as well as more advanced imaging techniques, has allowed the relationship between ER shape and function to come into focus. These studies have also revealed unexpected new functions of the ER and novel ER domains regulating alterations in ER dynamics. The importance of ER structure has become evident as recent research has identified diseases linked to mutations in ER-shaping proteins. In this review, we discuss what is known about the maintenance of ER architecture, the relationship between ER structure and function, and diseases associated with defects in ER structure.
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Affiliation(s)
- L M Westrate
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80303;
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49
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Buchnik L, Abu-Abied M, Sadot E. Role of plant myosins in motile organelles: is a direct interaction required? JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2015; 57:23-30. [PMID: 25196231 DOI: 10.1111/jipb.12282] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 08/31/2014] [Indexed: 06/03/2023]
Abstract
Plant organelles are highly motile, with speed values of 3-7 µm/s in cells of land plants and about 20-60 µm/s in characean algal cells. This movement is believed to be important for rapid distribution of materials around the cell, for the plant's ability to respond to environmental biotic and abiotic signals and for proper growth. The main machinery that propels motility of organelles within plant cells is based on the actin cytoskeleton and its motor proteins the myosins. Most plants express multiple members of two main classes: myosin VIII and myosin XI. While myosin VIII has been characterized as a slow motor protein, myosins from class XI were found to be the fastest motor proteins known in all kingdoms. Paradoxically, while it was found that myosins from class XI regulate most organelle movement, it is not quite clear how or even if these motor proteins attach to the organelles whose movement they regulate.
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Affiliation(s)
- Limor Buchnik
- The Institute of Plant Sciences, The Volcani Center, ARO, PO Box 6, Bet-Dagan, 50250, Israel
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50
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Jaipargas EA, Barton KA, Mathur N, Mathur J. Mitochondrial pleomorphy in plant cells is driven by contiguous ER dynamics. FRONTIERS IN PLANT SCIENCE 2015; 6:783. [PMID: 26442089 PMCID: PMC4585081 DOI: 10.3389/fpls.2015.00783] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 09/10/2015] [Indexed: 05/18/2023]
Abstract
Mitochondria are pleomorphic, double membrane-bound organelles involved in cellular energetics in all eukaryotes. Mitochondria in animal and yeast cells are typically tubular-reticulate structures and several micro-meters long but in green plants they are predominantly observed as 0.2-1.5 μm punctae. While fission and fusion, through the coordinated activity of several conserved proteins, shapes mitochondria, the endoplasmic reticulum (ER) has recently been identified as an additional player in this process in yeast and mammalian cells. The mitochondria-ER relationship in plant cells remains largely uncharacterized. Here, through live-imaging of the entire range of mitochondria pleomorphy we uncover the underlying basis for the predominantly punctate mitochondrial form in plants. We demonstrate that mitochondrial morphology changes in response to light and cytosolic sugar levels in an ER mediated manner. Whereas, large ER polygons and low dynamics under dark conditions favor mitochondrial fusion and elongation, small ER polygons result in increased fission and predominantly small mitochondria. Hypoxia also reduces ER dynamics and increases mitochondrial fusion to produce giant mitochondria. By observing elongated mitochondria in normal plants and fission-impaired Arabidopsis nmt1-2 and drp3a mutants we also establish that thin extensions called matrixules and a beads-on-a-string mitochondrial phenotype are direct consequences of mitochondria-ER interactions.
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Affiliation(s)
| | | | | | - Jaideep Mathur
- *Correspondence: Jaideep Mathur, Laboratory of Plant Development and Interactions, Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road, Guelph, ON N1G2W1, Canada
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