1
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Chang HY, Yang WY. Golgi quality control and autophagy. IUBMB Life 2022; 74:361-370. [PMID: 35274438 DOI: 10.1002/iub.2611] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 02/12/2022] [Indexed: 11/09/2022]
Abstract
Organelles can easily be disrupted by intracellular and extracellular factors. Studies on ER and mitochondria indicate that a wide range of responses are elicited upon organelle disruption. One response thought to be of particular importance is autophagy. Cells can target entire organelles into autophagosomes for removal. This wholesale nature makes autophagy a robust means for eliminating compromised organelles. Recently, it was demonstrated that the Golgi apparatus is a substrate of autophagy. On the other hand, various reports have shown that components traffic away from the Golgi for elimination in an autophagosome-independent manner when the Golgi apparatus is stressed. Future studies will reveal how these different pieces of machinery coordinate to drive Golgi degradation. Quantitative measurements will be needed to determine how much autophagy contributes to the maintenance of the Golgi apparatus.
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Affiliation(s)
- Hsiang-Yi Chang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Wei Yuan Yang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.,Institute of Biochemical Sciences, College of Life Sciences, National Taiwan University, Taipei, Taiwan
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2
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Wipi3 is essential for alternative autophagy and its loss causes neurodegeneration. Nat Commun 2020; 11:5311. [PMID: 33082312 PMCID: PMC7576787 DOI: 10.1038/s41467-020-18892-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 09/18/2020] [Indexed: 12/19/2022] Open
Abstract
Alternative autophagy is an Atg5/Atg7-independent type of autophagy that contributes to various physiological events. We here identify Wipi3 as a molecule essential for alternative autophagy, but which plays minor roles in canonical autophagy. Wipi3 binds to Golgi membranes and is required for the generation of isolation membranes. We establish neuron-specific Wipi3-deficient mice, which show behavioral defects, mainly as a result of cerebellar neuronal loss. The accumulation of iron and ceruloplasmin is also found in the neuronal cells. These abnormalities are suppressed by the expression of Dram1, which is another crucial molecule for alternative autophagy. Although Atg7-deficient mice show similar phenotypes to Wipi3-deficient mice, electron microscopic analysis shows that they have completely different subcellular morphologies, including the morphology of organelles. Furthermore, most Atg7/Wipi3 double-deficient mice are embryonic lethal, indicating that Wipi3 functions to maintain neuronal cells via mechanisms different from those of canonical autophagy. Unlike canonical macroautophagy, alternative autophagy does not require the factors Atg5 and Atg7. Here, the authors show that Wipi3 is essential for alternative autophagy, but not for canonical autophagy, and that Wipi3 functions to maintain neuronal cells via mechanisms different from those of canonical autophagy.
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3
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Bajaj L, Sharma J, di Ronza A, Zhang P, Eblimit A, Pal R, Roman D, Collette JR, Booth C, Chang KT, Sifers RN, Jung SY, Weimer JM, Chen R, Schekman RW, Sardiello M. A CLN6-CLN8 complex recruits lysosomal enzymes at the ER for Golgi transfer. J Clin Invest 2020; 130:4118-4132. [PMID: 32597833 PMCID: PMC7410054 DOI: 10.1172/jci130955] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 05/05/2020] [Indexed: 12/18/2022] Open
Abstract
Lysosomal enzymes are synthesized in the endoplasmic reticulum (ER) and transferred to the Golgi complex by interaction with the Batten disease protein CLN8 (ceroid lipofuscinosis, neuronal, 8). Here we investigated the relationship of this pathway with CLN6, an ER-associated protein of unknown function that is defective in a different Batten disease subtype. Experiments focused on protein interaction and trafficking identified CLN6 as an obligate component of a CLN6-CLN8 complex (herein referred to as EGRESS: ER-to-Golgi relaying of enzymes of the lysosomal system), which recruits lysosomal enzymes at the ER to promote their Golgi transfer. Mutagenesis experiments showed that the second luminal loop of CLN6 is required for the interaction of CLN6 with the enzymes but dispensable for interaction with CLN8. In vitro and in vivo studies showed that CLN6 deficiency results in inefficient ER export of lysosomal enzymes and diminished levels of the enzymes at the lysosome. Mice lacking both CLN6 and CLN8 did not display aggravated pathology compared with the single deficiencies, indicating that the EGRESS complex works as a functional unit. These results identify CLN6 and the EGRESS complex as key players in lysosome biogenesis and shed light on the molecular etiology of Batten disease caused by defects in CLN6.
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Affiliation(s)
- Lakshya Bajaj
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, Texas, USA
| | - Jaiprakash Sharma
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, Texas, USA
| | - Alberto di Ronza
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, Texas, USA
| | - Pengcheng Zhang
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
| | - Aiden Eblimit
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Rituraj Pal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, Texas, USA
| | - Dany Roman
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, USA
| | - John R. Collette
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, USA
| | - Clarissa Booth
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, South Dakota, USA
- Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, South Dakota, USA
| | - Kevin T. Chang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, Texas, USA
| | - Richard N. Sifers
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, USA
| | - Sung Y. Jung
- Department of Biochemistry and Molecular Biology
| | - Jill M. Weimer
- Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, South Dakota, USA
- Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, South Dakota, USA
| | - Rui Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Human Genome Sequencing Center, and
- Department of Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, USA
| | - Randy W. Schekman
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
- Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, California, USA
| | - Marco Sardiello
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, Texas, USA
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4
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Jain Goyal M, Zhao X, Bozhinova M, Andrade-López K, de Heus C, Schulze-Dramac S, Müller-McNicoll M, Klumperman J, Béthune J. A paralog-specific role of COPI vesicles in the neuronal differentiation of mouse pluripotent cells. Life Sci Alliance 2020; 3:3/9/e202000714. [PMID: 32665377 PMCID: PMC7368096 DOI: 10.26508/lsa.202000714] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 07/06/2020] [Accepted: 07/06/2020] [Indexed: 12/03/2022] Open
Abstract
The paralogous COPI coat subunit γ1-COP plays a unique role in promoting neurite outgrowth during the neuronal differentiation of mouse pluripotent cells. Coat protein complex I (COPI)–coated vesicles mediate membrane trafficking between Golgi cisternae as well as retrieval of proteins from the Golgi to the endoplasmic reticulum. There are several flavors of the COPI coat defined by paralogous subunits of the protein complex coatomer. However, whether paralogous COPI proteins have specific functions is currently unknown. Here, we show that the paralogous coatomer subunits γ1-COP and γ2-COP are differentially expressed during the neuronal differentiation of mouse pluripotent cells. Moreover, through a combination of genome editing experiments, we demonstrate that whereas γ-COP paralogs are largely functionally redundant, γ1-COP specifically promotes neurite outgrowth. Our work stresses a role of the COPI pathway in neuronal polarization and provides evidence for distinct functions for coatomer paralogous subunits in this process.
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Affiliation(s)
- Manu Jain Goyal
- Junior Research Group, Cluster of Excellence CellNetworks, Heidelberg, Germany.,Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Xiyan Zhao
- Junior Research Group, Cluster of Excellence CellNetworks, Heidelberg, Germany.,Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Mariya Bozhinova
- Junior Research Group, Cluster of Excellence CellNetworks, Heidelberg, Germany.,Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Karla Andrade-López
- Junior Research Group, Cluster of Excellence CellNetworks, Heidelberg, Germany.,Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Cecilia de Heus
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Sandra Schulze-Dramac
- RNA Regulation Group, Cluster of Excellence "Macromolecular Complexes," Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Michaela Müller-McNicoll
- RNA Regulation Group, Cluster of Excellence "Macromolecular Complexes," Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Judith Klumperman
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Julien Béthune
- Junior Research Group, Cluster of Excellence CellNetworks, Heidelberg, Germany .,Heidelberg University Biochemistry Center, Heidelberg, Germany
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5
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di Ronza A, Bajaj L, Sharma J, Sanagasetti D, Lotfi P, Adamski CJ, Collette J, Palmieri M, Amawi A, Popp L, Chang KT, Meschini MC, Leung HCE, Segatori L, Simonati A, Sifers RN, Santorelli FM, Sardiello M. CLN8 is an endoplasmic reticulum cargo receptor that regulates lysosome biogenesis. Nat Cell Biol 2018; 20:1370-1377. [PMID: 30397314 PMCID: PMC6277210 DOI: 10.1038/s41556-018-0228-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 10/04/2018] [Indexed: 12/21/2022]
Abstract
Organelle biogenesis requires proper transport of proteins from their site of synthesis to their target subcellular compartment1–3. Lysosomal enzymes are synthesized in the endoplasmic reticulum (ER) and traffic through the Golgi complex before being transferred to the endolysosomal system4–6, but how they are transferred from the ER to the Golgi is unknown. Here we show that ER-to-Golgi transfer of lysosomal enzymes requires CLN8, an ER-associated membrane protein whose loss of function leads to the lysosomal storage disorder, Neuronal Ceroid Lipofuscinosis 8 (a type of Batten disease)7. ER-to-Golgi trafficking of CLN8 requires interaction with the COPII and COPI machineries via specific export and retrieval signals localized in the cytosolic C-terminus of CLN8. CLN8 deficiency leads to depletion of soluble enzymes in the lysosome, thus impairing lysosome biogenesis. Binding to lysosomal enzymes requires CLN8’s second luminal loop and is abolished by some disease-causing mutations within this region. Our data establish an unanticipated example of an ER receptor serving the biogenesis of an organelle and suggest that impaired transport of lysosomal enzymes underlies Batten disease caused by mutations in CLN8.
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Affiliation(s)
- Alberto di Ronza
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Lakshya Bajaj
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Jaiprakash Sharma
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Deepthi Sanagasetti
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Parisa Lotfi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Carolyn Joy Adamski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - John Collette
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, USA
| | - Michela Palmieri
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Abdallah Amawi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Lauren Popp
- Departments of Bioengineering, Chemical and Biomolecular Engineering, and Biochemistry and Cell Biology, Rice University, Houston, TX, USA
| | - Kevin Tommy Chang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA.,Department of Biosciences, Rice University, Houston, TX, USA
| | - Maria Chiara Meschini
- Department of Neurological and Movement Sciences, University of Verona, Verona, Italy
| | - Hon-Chiu Eastwood Leung
- Departments of Medicine, Pediatrics, and Molecular and Cellular Biology, Dan Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Laura Segatori
- Departments of Bioengineering, Chemical and Biomolecular Engineering, and Biochemistry and Cell Biology, Rice University, Houston, TX, USA
| | - Alessandro Simonati
- Department of Neurological and Movement Sciences, University of Verona, Verona, Italy
| | - Richard Norman Sifers
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, USA
| | | | - Marco Sardiello
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA.
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6
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Nüße J, Blumrich EM, Mirastschijski U, Kappelmann L, Kelm S, Dietz F. Intra- or extra-exosomal secretion of HDGF isoforms: the extraordinary function of the HDGF-A N-terminal peptide. Biol Chem 2017; 398:793-811. [DOI: 10.1515/hsz-2016-0315] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 12/05/2016] [Indexed: 12/25/2022]
Abstract
Abstract
Hepatoma-derived growth factor (HDGF) is a protein with diverse intracellular functions. Moreover, after non-conventional secretion, extracellular HDGF is able to influence different signaling pathways, leading for example to induction of processes like epithelial-mesenchymal transition (EMT) and cell migration. Intriguingly, in recent proteome studies, HDGF was also found secreted by special microvesicles called exosomes. Recently, we demonstrated the existence of two new HDGF isoforms (B and C). These isoforms are involved in different cellular processes than HDGF-A. Along this line, in the present study we discovered that full length HDGF-A clearly is located inside of exosomes, whereas the isoforms HDGF-B and HDGF-C are found exclusively on the outer surface. Furthermore, while HDGF-B and HDGF-C seem to use exosomes mediated pathway exclusively, HDGF-A was found also as unbound protein in the conditioned media. The new finding of an intra- or extra-exosomal localisation of protein splice variants opens a fascinating new perspective concerning functional diversity of HDGF isoforms. Dysregulation of HDGF expression during cancer development and tumor progression is a commonly known fact. With our new findings, unraveling the potential functional impact according to physiological versus pathophysiologically altered levels and compositions of intra- and extra-exosomal HDGF has to be addressed in future studies.
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7
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Ejzykowicz DE, Locken KM, Ruiz FJ, Manandhar SP, Olson DK, Gharakhanian E. Hygromycin B hypersensitive (hhy) mutants implicate an intact trans-Golgi and late endosome interface in efficient Tor1 vacuolar localization and TORC1 function. Curr Genet 2016; 63:531-551. [PMID: 27812735 DOI: 10.1007/s00294-016-0660-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 10/20/2016] [Accepted: 10/22/2016] [Indexed: 12/18/2022]
Abstract
Saccharomyces cerevisiae vacuoles are functionally analogous to mammalian lysosomes. Both also serve as physical platforms for Tor Complex 1 (TORC1) signal transduction, the master regulator of cellular growth and proliferation. Hygromycin B is a eukaryotic translation inhibitor. We recently reported on hygromycin B hypersensitive (hhy) mutants that fail to grow at subtranslation inhibitory concentrations of the drug and exhibit vacuolar defects (Banuelos et al. in Curr Genet 56:121-137, 2010). Here, we show that hhy phenotype is not due to increased sensitivity to translation inhibition and establish a super HHY (s-HHY) subgroup of genes comprised of ARF1, CHC1, DRS2, SAC1, VPS1, VPS34, VPS45, VPS52, and VPS54 that function exclusively or inclusively at trans-Golgi and late endosome interface. Live cell imaging of s-hhy mutants revealed that hygromycin B treatment disrupts vacuolar morphology and the localization of late endosome marker Pep12, but not that of late endosome-independent vacuolar SNARE Vam3. This, along with normal post-late endosome trafficking of the vital dye FM4-64, establishes that severe hypersensitivity to hygromycin B correlates specifically with compromised trans-Golgi and late endosome interface. We also show that Tor1p vacuolar localization and TORC1 anabolic functions, including growth promotion and phosphorylation of its direct substrate Sch9, are compromised in s-hhy mutants. Thus, an intact trans-Golgi and late endosome interface is a requisite for efficient Tor1 vacuolar localization and TORC1 function.
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Affiliation(s)
- Daniele E Ejzykowicz
- Department of Biological Sciences, California State University Long Beach, 1250 Bellflower Blvd, Long Beach, CA, 90840, USA
| | - Kristopher M Locken
- Department of Biological Sciences, California State University Long Beach, 1250 Bellflower Blvd, Long Beach, CA, 90840, USA
| | - Fiona J Ruiz
- Department of Biological Sciences, California State University Long Beach, 1250 Bellflower Blvd, Long Beach, CA, 90840, USA.,Department of Radiation Oncology, Cancer Biology Division, Washington University School of Medicine, Saint Louis, MO, 63108, USA
| | - Surya P Manandhar
- Department of Biological Sciences, California State University Long Beach, 1250 Bellflower Blvd, Long Beach, CA, 90840, USA
| | - Daniel K Olson
- Department of Biological Sciences, California State University Long Beach, 1250 Bellflower Blvd, Long Beach, CA, 90840, USA.,Inouye Center for Microbial Oceanography, Research and Education, University of Hawaii, Manoa, Honolulu, HI, 96822, USA
| | - Editte Gharakhanian
- Department of Biological Sciences, California State University Long Beach, 1250 Bellflower Blvd, Long Beach, CA, 90840, USA.
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8
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Yamaguchi H, Arakawa S, Kanaseki T, Miyatsuka T, Fujitani Y, Watada H, Tsujimoto Y, Shimizu S. Golgi membrane-associated degradation pathway in yeast and mammals. EMBO J 2016; 35:1991-2007. [PMID: 27511903 DOI: 10.15252/embj.201593191] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 07/14/2016] [Indexed: 01/08/2023] Open
Abstract
Autophagy is a cellular process that degrades subcellular constituents, and is conserved from yeast to mammals. Although autophagy is believed to be essential for living cells, cells lacking Atg5 or Atg7 are healthy, suggesting that a non-canonical degradation pathway exists to compensate for the lack of autophagy. In this study, we show that the budding yeast Saccharomyces cerevisiae, which lacks Atg5, undergoes bulk protein degradation using Golgi-mediated structures to compensate for autophagy when treated with amphotericin B1, a polyene antifungal drug. We named this mechanism Golgi membrane-associated degradation (GOMED) pathway. This process is driven by the disruption of PI(4)P-dependent anterograde trafficking from the Golgi, and it also exists in Atg5-deficient mammalian cells. Biologically, when an Atg5-deficient β-cell line and Atg7-deficient β-cells were cultured in glucose-deprived medium, a disruption in the secretion of insulin granules from the Golgi occurred, and GOMED was induced to digest these (pro)insulin granules. In conclusion, GOMED is activated by the disruption of PI(4)P-dependent anterograde trafficking in autophagy-deficient yeast and mammalian cells.
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Affiliation(s)
- Hirofumi Yamaguchi
- Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Satoko Arakawa
- Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Toku Kanaseki
- Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
| | - Takeshi Miyatsuka
- Department of Medicine, Metabolism & Endocrinology, Juntendo University, Bunkyo-ku, Tokyo, Japan
| | - Yoshio Fujitani
- Department of Medicine, Metabolism & Endocrinology, Juntendo University, Bunkyo-ku, Tokyo, Japan
| | - Hirotaka Watada
- Department of Medicine, Metabolism & Endocrinology, Juntendo University, Bunkyo-ku, Tokyo, Japan
| | - Yoshihide Tsujimoto
- Department of Molecular and Cellular Biology, Research Institute, Osaka Medical Center for Cancer and Cardiovascular Diseases, Higashinari, Osaka, Japan
| | - Shigeomi Shimizu
- Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Bunkyo-ku, Tokyo, Japan
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9
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Zhang XM, Yan XY, Zhang B, Yang Q, Ye M, Cao W, Qiang WB, Zhu LJ, Du YL, Xu XX, Wang JS, Xu F, Lu W, Qiu S, Yang W, Luo JH. Activity-induced synaptic delivery of the GluN2A-containing NMDA receptor is dependent on endoplasmic reticulum chaperone Bip and involved in fear memory. Cell Res 2015; 25:818-36. [PMID: 26088419 DOI: 10.1038/cr.2015.75] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 03/02/2015] [Accepted: 05/04/2015] [Indexed: 11/09/2022] Open
Abstract
The N-methyl-D-aspartate receptor (NMDAR) in adult forebrain is a heterotetramer mainly composed of two GluN1 subunits and two GluN2A and/or GluN2B subunits. The synaptic expression and relative numbers of GluN2A- and GluN2B-containing NMDARs play critical roles in controlling Ca(2+)-dependent signaling and synaptic plasticity. Previous studies have suggested that the synaptic trafficking of NMDAR subtypes is differentially regulated, but the precise molecular mechanism is not yet clear. In this study, we demonstrated that Bip, an endoplasmic reticulum (ER) chaperone, selectively interacted with GluN2A and mediated the neuronal activity-induced assembly and synaptic incorporation of the GluN2A-containing NMDAR from dendritic ER. Furthermore, the GluN2A-specific synaptic trafficking was effectively disrupted by peptides interrupting the interaction between Bip and GluN2A. Interestingly, fear conditioning in mice was disrupted by intraperitoneal injection of the interfering peptide before training. In summary, we have uncovered a novel mechanism for the activity-dependent supply of synaptic GluN2A-containing NMDARs, and demonstrated its relevance to memory formation.
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Affiliation(s)
- Xiao-min Zhang
- 1] Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China [2] Department of Physiology, Kunming Medical University, Kunming, Yunnan 650500, China
| | - Xun-yi Yan
- Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Bin Zhang
- Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Qian Yang
- Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Mao Ye
- Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Wei Cao
- Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Wen-bin Qiang
- Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Li-jun Zhu
- Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yong-lan Du
- Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Xing-xing Xu
- Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Jia-sheng Wang
- Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Fei Xu
- Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Wei Lu
- Key Laboratory of Developmental Genes and Human Disease (Ministry of Education of China), Institute of Life Sciences, Southeast University, Nanjing, Jiangsu 211189, China
| | - Shuang Qiu
- Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Wei Yang
- Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Jian-hong Luo
- Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
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10
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Jarvela T, Linstedt AD. Irradiation-induced protein inactivation reveals Golgi enzyme cycling to cell periphery. J Cell Sci 2012; 125:973-80. [PMID: 22421362 DOI: 10.1242/jcs.094441] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acute inhibition is a powerful technique to test proteins for direct roles and order their activities in a pathway, but as a general gene-based strategy, it is mostly unavailable in mammalian systems. As a consequence, the precise roles of proteins in membrane trafficking have been difficult to assess in vivo. Here we used a strategy based on a genetically encoded fluorescent protein that generates highly localized and damaging reactive oxygen species to rapidly inactivate exit from the endoplasmic reticulum (ER) during live-cell imaging and address the long-standing question of whether the integrity of the Golgi complex depends on constant input from the ER. Light-induced blockade of ER exit immediately perturbed Golgi membranes, and surprisingly, revealed that cis-Golgi-resident proteins continuously cycle to peripheral ER-Golgi intermediate compartment (ERGIC) membranes and depend on ER exit for their return to the Golgi. These experiments demonstrate that ER exit and extensive cycling of cis-Golgi components to the cell periphery sustain the mammalian Golgi complex.
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Affiliation(s)
- Timothy Jarvela
- Department of Biological Sciences, Carnegie Mellon University, 4400 5th Avenue, Pittsburgh, PA 15213, USA
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11
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RNAi screening reveals requirement for host cell secretory pathway in infection by diverse families of negative-strand RNA viruses. Proc Natl Acad Sci U S A 2011; 108:19036-41. [PMID: 22065774 DOI: 10.1073/pnas.1113643108] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Negative-strand (NS) RNA viruses comprise many pathogens that cause serious diseases in humans and animals. Despite their clinical importance, little is known about the host factors required for their infection. Using vesicular stomatitis virus (VSV), a prototypic NS RNA virus in the family Rhabdoviridae, we conducted a human genome-wide siRNA screen and identified 72 host genes required for viral infection. Many of these identified genes were also required for infection by two other NS RNA viruses, the lymphocytic choriomeningitis virus of the Arenaviridae family and human parainfluenza virus type 3 of the Paramyxoviridae family. Genes affecting different stages of VSV infection, such as entry/uncoating, gene expression, and assembly/release, were identified. Depletion of the proteins of the coatomer complex I or its upstream effectors ARF1 or GBF1 led to detection of reduced levels of VSV RNA. Coatomer complex I was also required for infection of lymphocytic choriomeningitis virus and human parainfluenza virus type 3. These results highlight the evolutionarily conserved requirements for gene expression of diverse families of NS RNA viruses and demonstrate the involvement of host cell secretory pathway in the process.
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12
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Banuelos MG, Moreno DE, Olson DK, Nguyen Q, Ricarte F, Aguilera-Sandoval CR, Gharakhanian E. Genomic analysis of severe hypersensitivity to hygromycin B reveals linkage to vacuolar defects and new vacuolar gene functions in Saccharomyces cerevisiae. Curr Genet 2009; 56:121-37. [PMID: 20043226 DOI: 10.1007/s00294-009-0285-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Revised: 11/30/2009] [Accepted: 12/16/2009] [Indexed: 12/19/2022]
Abstract
The vacuole of Saccharomyces cerevisiae has been a seminal model for studies of lysosomal trafficking, biogenesis, and function. Several yeast mutants defective in such vacuolar events have been unable to grow at low levels of hygromycin B, an aminoglycoside antibiotic. We hypothesized that such severe hypersensitivity to hygromycin B (hhy) is linked to vacuolar defects and performed a genomic screen for the phenotype using a haploid deletion strain library of non-essential genes. Fourteen HHY genes were initially identified and were subjected to bioinformatics analyses. The uncovered hhy mutants were experimentally characterized with respect to vesicular trafficking, vacuole morphology, and growth under various stress and drug conditions. The combination of bioinformatics analyses and phenotypic characterizations implicate defects in vesicular trafficking, vacuole fusion/fission, or vacuole function in all hhy mutants. The collection was enriched for sensitivity to monensin, indicative of vacuolar trafficking defects. Additionally, all hhy mutants showed severe sensitivities to rapamycin and caffeine, suggestive of TOR kinase pathway defects. Our experimental results also establish a new role in vacuolar and vesicular functions for two genes: PAF1, encoding a RNAP II-associated protein required for expression of cell cycle-regulated genes, and TPD3, encoding the regulatory subunit of protein phosphatase 2A. Thus, our results support linkage between severe hypersensitivity to hygromycin B and vacuolar defects.
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Affiliation(s)
- M G Banuelos
- Department of Biological Sciences, California State University at Long Beach, 1250 Bellflower Blvd, Long Beach, CA 90840, USA
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13
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A role for the host coatomer and KDEL receptor in early vaccinia biogenesis. Proc Natl Acad Sci U S A 2008; 106:163-8. [PMID: 19109439 DOI: 10.1073/pnas.0811631106] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Members of the poxvirus family have been investigated for their applications as vaccines and expression vectors and, more recently, because of concern for their potential as biological weapons. Vaccinia virus, the prototypic member, evolves through multiple forms during its replication. Here, we show a surprising way by which vaccinia hijacks coatomer for early viral biogenesis. Whereas coatomer forms COPI vesicles in the host early secretory system, vaccinia formation bypasses this role of coatomer, but instead, depends on coatomer interacting with the host KDEL receptor. To gain insight into the viral roles of these two host proteins, we have detected them on the earliest recognized viral forms. These findings not only suggest insights into early vaccinia biogenesis but also reveal an alternate mechanism by which coatomer acts.
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14
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Dixit G, Mikoryak C, Hayslett T, Bhat A, Draper RK. Cholera toxin up-regulates endoplasmic reticulum proteins that correlate with sensitivity to the toxin. Exp Biol Med (Maywood) 2008; 233:163-75. [PMID: 18222971 DOI: 10.3181/0705-rm-132] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Cholera toxin (CT) contains one A chain and five B chains. The A chain is an enzyme that covalently modifies a trimeric G protein in the cytoplasm, resulting in the overproduction of cAMP. The B chain binds the glycosphingolipid G(M1), the cell surface receptor for CT, which initiates receptor-mediated endocytosis of the toxin. After endocytosis, CT enters the endoplasmic reticulum (ER) via retrograde vesicular traffic where the A chain retro-translocates through the ER membrane to reach the cytoplasm. The retro-translocation mechanism is poorly understood, but may involve proteins of the ER stress response, including the ER associated degradation (ERAD) pathway. We report here that treating cells with CT or CTB quickly up-regulates the levels of BiP, Derlin-1, and Derlin-2, known participants in the ER stress response and ERAD. CT did not induce calnexin, another known responder to ER stress, indicating that the CT-mediated induction of ER proteins is selective in this time frame. These data suggest that CT may promote retro-translocation of the A chain to the cytoplasm by rapidly up-regulating a set of ER proteins involved in the retro-translocation process. In support of this idea, a variety of conditions that induced BiP, Derlin-1, and Derlin-2 sensitized cells to CT and conditions that inhibited their induction de-sensitized cells to CT. Moreover, specifically suppressing Derlin-1 with siRNA protected cells from CT. In addition, Derlin-1 co-immunoprecipitated with CTA or CTB from CT-treated cells using anti-CTA or anti-CTB antibodies. Altogether, the results are consistent with the hypothesis that the B chain of CT up-regulates ER proteins that may assist in the retro-translocation of the A chain across the ER membrane.
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Affiliation(s)
- Garima Dixit
- The Molecular and Cell Biology Department, FO31, The University of Texas at Dallas, Richardson, TX 75083-0688, USA
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15
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Szul T, Grabski R, Lyons S, Morohashi Y, Shestopal S, Lowe M, Sztul E. Dissecting the role of the ARF guanine nucleotide exchange factor GBF1 in Golgi biogenesis and protein trafficking. J Cell Sci 2007; 120:3929-40. [PMID: 17956946 DOI: 10.1242/jcs.010769] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
COPI recruitment to membranes appears to be essential for the biogenesis of the Golgi and for secretory trafficking. Preventing COPI recruitment by expressing inactive forms of the ADP-ribosylation factor (ARF) or the ARF-activating guanine nucleotide exchange factor GBF1, or by treating cells with brefeldin A (BFA), causes the collapse of the Golgi into the endoplasmic reticulum (ER) and arrests trafficking of soluble and transmembrane proteins at the ER. Here, we assess COPI function in Golgi biogenesis and protein trafficking by preventing COPI recruitment to membranes by removing GBF1. We report that siRNA-mediated depletion of GBF1 causes COPI dispersal but does not lead to collapse of the Golgi. Instead, it causes extensive tubulation of the cis-Golgi. The Golgi-derived tubules target to peripheral ER-Golgi intermediate compartment (ERGIC) sites and create dynamic continuities between the ERGIC and the cis-Golgi compartment. COPI dispersal in GBF1-depleted cells causes dramatic inhibition of the trafficking of transmembrane proteins. Unexpectedly, soluble proteins continue to be secreted from GBF1-depleted cells. Our findings suggest that a secretory pathway capable of trafficking soluble proteins can be maintained in cells in which COPI recruitment is compromised by GBF1 depletion. However, the trafficking of transmembrane proteins through the existing pathway requires GBF1-mediated ARF activation and COPI recruitment.
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Affiliation(s)
- Tomasz Szul
- Department of Cell Biology, University of Alabama at Birmingham, 1918 University Blvd, Birmingham, AL 35924, USA
| | - Robert Grabski
- Department of Cell Biology, University of Alabama at Birmingham, 1918 University Blvd, Birmingham, AL 35924, USA
| | - Susan Lyons
- Department of Cell Biology, University of Alabama at Birmingham, 1918 University Blvd, Birmingham, AL 35924, USA
| | - Yuichi Morohashi
- University of Manchester, Faculty of Life Sciences, Manchester M13 9PT, UK
| | - Svetlana Shestopal
- Department of Cell Biology, University of Alabama at Birmingham, 1918 University Blvd, Birmingham, AL 35924, USA
| | - Martin Lowe
- University of Manchester, Faculty of Life Sciences, Manchester M13 9PT, UK
| | - Elizabeth Sztul
- Department of Cell Biology, University of Alabama at Birmingham, 1918 University Blvd, Birmingham, AL 35924, USA
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16
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Derby MC, Gleeson PA. New Insights into Membrane Trafficking and Protein Sorting. INTERNATIONAL REVIEW OF CYTOLOGY 2007; 261:47-116. [PMID: 17560280 DOI: 10.1016/s0074-7696(07)61002-x] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Protein transport in the secretory and endocytic pathways is a multistep process involving the generation of transport carriers loaded with defined sets of cargo, the shipment of the cargo-loaded transport carriers between compartments, and the specific fusion of these transport carriers with a target membrane. The regulation of these membrane-mediated processes involves a complex array of protein and lipid interactions. As the machinery and regulatory processes of membrane trafficking have been defined, it is increasingly apparent that membrane transport is intimately connected with a number of other cellular processes, such as quality control in the endoplasmic reticulum (ER), cytoskeletal dynamics, receptor signaling, and mitosis. The fidelity of membrane trafficking relies on the correct assembly of components on organelles. Recruitment of peripheral proteins plays a critical role in defining organelle identity and the establishment of membrane subdomains, essential for the regulation of vesicle transport. The molecular mechanisms for the biogenesis of membrane subdomains are also central to understanding how cargo is sorted and segregated and how different populations of transport carriers are generated. In this review we will focus on the emerging themes of organelle identity, membrane subdomains, regulation of Golgi trafficking, and advances in dissecting pathways in physiological systems.
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Affiliation(s)
- Merran C Derby
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
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17
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Horton AC, Rácz B, Monson EE, Lin AL, Weinberg RJ, Ehlers MD. Polarized secretory trafficking directs cargo for asymmetric dendrite growth and morphogenesis. Neuron 2006; 48:757-71. [PMID: 16337914 DOI: 10.1016/j.neuron.2005.11.005] [Citation(s) in RCA: 321] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2005] [Revised: 08/08/2005] [Accepted: 11/04/2005] [Indexed: 12/27/2022]
Abstract
Proper growth of dendrites is critical to the formation of neuronal circuits, but the cellular machinery that directs the addition of membrane components to generate dendritic architecture remains obscure. Here, we demonstrate that post-Golgi membrane trafficking is polarized toward longer dendrites of hippocampal pyramidal neurons in vitro and toward apical dendrites in vivo. Small Golgi outposts partition selectively into longer dendrites and are excluded from axons. In dendrites, Golgi outposts concentrate at branchpoints where they engage in post-Golgi trafficking. Within the cell body, the Golgi apparatus orients toward the longest dendrite, and this Golgi polarity precedes asymmetric dendrite growth. Manipulations that selectively block post-Golgi trafficking halt dendrite growth in developing neurons and cause a shrinkage of dendrites in mature pyramidal neurons. Further, disruption of Golgi polarity produces neurons with symmetric dendritic arbors lacking a single longest principal dendrite. These results define a novel polarized organization of neuronal secretory trafficking and demonstrate a mechanistic link between directed membrane trafficking and asymmetric dendrite growth.
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Affiliation(s)
- April C Horton
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA
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18
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Abujarour RJ, Dalal S, Hanson PI, Draper RK. p97 Is in a complex with cholera toxin and influences the transport of cholera toxin and related toxins to the cytoplasm. J Biol Chem 2005; 280:15865-71. [PMID: 15691847 DOI: 10.1074/jbc.m406316200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Certain protein toxins, including cholera toxin, ricin, and Pseudomonas aeruginosa exotoxin A, are transported to the lumen of the endoplasmic reticulum where they retro-translocate across the endoplasmic reticulum membrane to enter the cytoplasm. The mechanism of retrotranslocation is poorly understood but may involve the endoplasmic reticulum-associated degradation pathway. The AAA ATPase p97 (also called valosin-containing protein) participates in the retro-translocation of cellular endoplasmic reticulum-associated degradation substrates and is therefore a candidate to participate in the retrotranslocation of protein toxins. To investigate whether p97 functions in toxin delivery to the cytoplasm, we measured the sensitivity to toxins of cells expressing either wild-type p97 or a dominant ATPase-defective p97 mutant under control of a tetracycline-inducible promoter. The rate at which cholera toxin and related toxins entered the cytoplasm was reduced in cells expressing the ATPase-defective p97, suggesting that the toxins might interact with p97. To detect interaction, the cholera toxin A chain was immunoprecipitated from cholera toxin-treated Vero cells, and co-immunoprecipitation of p97 was assessed by immunoblotting. The immunoprecipitates contained both cholera toxin A chain and p97, evidence that the two proteins are in a complex. Altogether, these results provide functional and structural evidence that p97 participates in the transport of cholera toxin to the cytoplasm.
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Affiliation(s)
- Ramzey J Abujarour
- Molecular and Cell Biology Department, The University of Texas at Dallas, Richardson, Texas 75083-0688, USA
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19
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Chen A, AbuJarour RJ, Draper RK. Evidence that the transport of ricin to the cytoplasm is independent of both Rab6A and COPI. J Cell Sci 2003; 116:3503-10. [PMID: 12865434 DOI: 10.1242/jcs.00641] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cholera toxin, Shiga toxin and ricin are examples of protein toxins that require retrograde transport from the Golgi complex into the endoplasmic reticulum (ER) to express their cytotoxic activities and different toxins appear to use different pathways of retrograde transport. Cholera toxin contains the mammalian retrograde targeting signal KDEL and is believed to exploit the coat protein I (COPI) and KDEL receptor-dependent pathway to go from the Golgi complex to the ER. Shiga toxin, however, has no KDEL sequence to specify its inclusion in COPI-coated retrograde vesicles and is believed to use a recently discovered COPI-independent and Rab6A-dependent retrograde pathway to enter the ER. Ricin, like Shiga toxin, does not contain a KDEL sequence and is therefore a candidate to use the COPI-independent and Rab6A-dependent pathway of retrograde transport to access the ER. We measured the effect of the GDP-restricted mutant of Rab6A (Rab6A-T27N) on the cytotoxic activity of ricin and found that expressing Rab6A-T27N in cells did not inhibit the cytotoxicity of ricin, suggesting that ricin enters the cytoplasm by a retrograde pathway that does not involve Rab6A. Moreover, ricin still intoxicated cells when Rab6A and COPI were simultaneously inhibited, implying that ricin requires neither Rab6A nor COPI to intoxicate cells.
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Affiliation(s)
- Alice Chen
- The Molecular and Cell Biology Department, FO31, The University of Texas at Dallas, Box 830688, Richardson, TX 75083-0688, USA
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20
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Chen A, Hu T, Mikoryak C, Draper RK. Retrograde transport of protein toxins under conditions of COPI dysfunction. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1589:124-39. [PMID: 12007788 DOI: 10.1016/s0167-4889(02)00163-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Retrograde transport dependent on coat protein I (COPI) was impaired using two different approaches and the effects on the retrograde transport of protein toxins were investigated. One approach was to study ldlF cells that express a temperature-sensitive defect in the epsilon-COP subunit of COPI. The second approach was to treat cells with 1,3-cyclohexanebis(methylamine) (CBM), a drug that interferes with the binding of COPI to Golgi membranes. With both approaches, cells remained sensitive to a variety of protein toxins regardless of whether the toxins contained a KDEL motif. Moreover, cholera toxin, which contains a KDEL sequence, was observed by immunofluorescence microscopy to enter the endoplasmic reticulum of Vero cells in the presence of CBM. These data support published evidence indicating the presence in cells of a COPI- and KDEL receptor-independent pathway of retrograde transport from the Golgi complex to the endoplasmic reticulum. In addition, the results suggest that certain toxins containing a KDEL motif may use either the COPI-dependent or COPI-independent pathway of retrograde transport.
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Affiliation(s)
- Alice Chen
- Molecular and Cell Biology Department, FO31, University of Texas at Dallas, Box 830688, Richardson, TX 75083-0688, USA
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21
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Puthenveedu MA, Linstedt AD. Evidence that Golgi structure depends on a p115 activity that is independent of the vesicle tether components giantin and GM130. J Cell Biol 2001; 155:227-38. [PMID: 11591729 PMCID: PMC2198842 DOI: 10.1083/jcb.200105005] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Inhibition of the putative coatomer protein I (COPI) vesicle tethering complex, giantin-p115-GM130, may contribute to mitotic Golgi breakdown. However, neither this, nor the role of the giantin-p115-GM130 complex in the maintenance of Golgi structure has been demonstrated in vivo. Therefore, we generated antibodies directed against the mapped binding sites in each protein of the complex and injected these into mammalian tissue culture cells. Surprisingly, the injected anti-p115 and antigiantin antibodies caused proteasome-mediated degradation of the corresponding antigens. Reduction of p115 levels below detection led to COPI-dependent Golgi fragmentation and apparent accumulation of Golgi-derived vesicles. In contrast, neither reduction of giantin below detectable levels, nor inhibition of p115 binding to GM130, had any detectable effect on Golgi structure or Golgi reassembly after cell division or brefeldin A washout. These observations indicate that inhibition of p115 can induce a mitotic-like Golgi disassembly, but its essential role in Golgi structure is independent of its Golgi-localized binding partners giantin and GM130.
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Affiliation(s)
- M A Puthenveedu
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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22
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Takahashi K, Nuckolls GH, Takahashi I, Nonaka K, Nagata M, Ikura T, Slavkin HC, Shum L. Msx2 is a repressor of chondrogenic differentiation in migratory cranial neural crest cells. Dev Dyn 2001; 222:252-62. [PMID: 11668602 DOI: 10.1002/dvdy.1185] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
During early mouse embryogenesis, cranial neural crest cells (CNCC) emigrate from the posterior midbrain and rhombomeres 1 and 2 of the anterior hindbrain into the first branchial arch-derived maxillary and mandibular processes and there provide cell lineages for several phenotypes, including cartilage, bone, and tooth. Here, we report that Sox9 and Msx2 were coexpressed in a subpopulation of CNCC during their migration. Because Sox9 is a transactivator of chondrogenesis, and Msx genes can act as transcriptional repressors, we hypothesized that Sox9 expression indicates the determination of CNCC-derived chondrogenic cell lineage and that Msx2 represses chondrogenic differentiation until CNCC migration is completed within the mandibular processes. To test whether Msx2 represses chondrogenesis, we designed experiments to inhibit Msx2 function in migratory CNCC in primary cultures through the expression of loss-of-function Msx2 mutants. We showed that infection of migratory CNCC with adenovirus Msx2 mutants accelerated the rate and extent of chondrogenesis, as indicated by the expression level of type II collagen and aggrecan, and the amount of alcian blue staining. Adenovirus infections did not apparently interfere with CNCC proliferation or migration. These findings suggest that an important early event in craniofacial morphogenesis is a transient expression of both Sox9 and Msx2 during emigration into the forming mandibular processes followed by restricted expression of Sox9 within CNCC- derived chondroprogenitor cells. We conclude that Msx2 serves as a repressor of chondrogenic differentiation during CNCC migration.
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Affiliation(s)
- K Takahashi
- Craniofacial Development Section, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, 6 Center Drive, Bethesda, MD 20892-2745, USA
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23
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Draper RK, Hudson RT, Hu T. Use of aminoglycoside antibiotics and related compounds to study ADP-ribosylation factor (ARF)/coatomer function in Golgi traffic. Methods Enzymol 2001; 329:372-9. [PMID: 11210556 DOI: 10.1016/s0076-6879(01)29098-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Affiliation(s)
- R K Draper
- Department of Molecular and Cell Biology, University of Texas at Dallas, Richardson, Texas 75083-0688, USA
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24
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Sullivan BM, Harrison-Lavoie KJ, Marshansky V, Lin HY, Kehrl JH, Ausiello DA, Brown D, Druey KM. RGS4 and RGS2 bind coatomer and inhibit COPI association with Golgi membranes and intracellular transport. Mol Biol Cell 2000; 11:3155-68. [PMID: 10982407 PMCID: PMC14982 DOI: 10.1091/mbc.11.9.3155] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
COPI, a protein complex consisting of coatomer and the small GTPase ARF1, is an integral component of some intracellular transport carriers. The association of COPI with secretory membranes has been implicated in the maintenance of Golgi integrity and the normal functioning of intracellular transport in eukaryotes. The regulator of G protein signaling, RGS4, interacted with the COPI subunit beta'-COP in a yeast two-hybrid screen. Both recombinant RGS4 and RGS2 bound purified recombinant beta'-COP in vitro. Endogenous cytosolic RGS4 from NG108 cells and RGS2 from HEK293T cells cofractionated with the COPI complex by gel filtration. Binding of beta'-COP to RGS4 occurred through two dilysine motifs in RGS4, similar to those contained in some aminoglycoside antibiotics that are known to bind coatomer. RGS4 inhibited COPI binding to Golgi membranes independently of its GTPase-accelerating activity on G(ialpha). In RGS4-transfected LLC-PK1 cells, the amount of COPI in the Golgi region was considerably reduced compared with that in wild-type cells, but there was no detectable difference in the amount of either Golgi-associated ARF1 or the integral Golgi membrane protein giantin, indicating that Golgi integrity was preserved. In addition, RGS4 expression inhibited trafficking of aquaporin 1 to the plasma membrane in LLC-PK1 cells and impaired secretion of placental alkaline phosphatase from HEK293T cells. The inhibitory effect of RGS4 in these assays was independent of GTPase-accelerating activity but correlated with its ability to bind COPI. Thus, these data support the hypothesis that these RGS proteins sequester coatomer in the cytoplasm and inhibit its recruitment onto Golgi membranes, which may in turn modulate Golgi-plasma membrane or intra-Golgi transport.
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Affiliation(s)
- B M Sullivan
- Renal Unit, Program in Membrane Biology, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
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25
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Conboy MJ, Cyert MS. Luv1p/Rki1p/Tcs3p/Vps54p, a yeast protein that localizes to the late Golgi and early endosome, is required for normal vacuolar morphology. Mol Biol Cell 2000; 11:2429-43. [PMID: 10888679 PMCID: PMC14930 DOI: 10.1091/mbc.11.7.2429] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
We have characterized LUV1/RKI1/TCS3/VPS54, a novel yeast gene required to maintain normal vacuolar morphology. The luv1 mutant was identified in a genetic screen for mutants requiring the phosphatase calcineurin for vegetative growth. luv1 mutants lack a morphologically intact vacuole and instead accumulate small vesicles that are acidified and contain the vacuolar proteins alkaline phosphatase and carboxypeptidase Y and the vacuolar membrane H(+)-ATPase. Endocytosis appears qualitatively normal in luv1 mutants, but some portion (28%) of carboxypeptidase Y is secreted. luv1 mutants are sensitive to several ions (Zn(2+), Mn(2+), and Cd(2+)) and to pH extremes. These mutants are also sensitive to hygromycin B, caffeine, and FK506, a specific inhibitor of calcineurin. Some vacuolar protein-sorting mutants display similar drug and ion sensitivities, including sensitivity to FK506. Luv1p sediments at 100,000 x g and can be solubilized by salt or carbonate, indicating that it is a peripheral membrane protein. A Green Fluorescent Protein-Luv1 fusion protein colocalizes with the dye FM 4-64 at the endosome, and hemagglutinin-tagged Luv1p colocalizes with the trans-Golgi network/endosomal protease Kex2p. Computer analysis predicts a short coiled-coil domain in Luv1p. We propose that this protein maintains traffic through or the integrity of the early endosome and that this function is required for proper vacuolar morphology.
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Affiliation(s)
- M J Conboy
- Department of Biological Sciences, Stanford University, Stanford, California 94305-5020, USA
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26
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Weidler M, Reinhard C, Friedrich G, Wieland FT, Rösch P. Structure of the cytoplasmic domain of p23 in solution: implications for the formation of COPI vesicles. Biochem Biophys Res Commun 2000; 271:401-8. [PMID: 10799309 DOI: 10.1006/bbrc.2000.2511] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Coatomer, the coat protein complex of coat protein (COPI) vesicles, is involved in the budding of these vesicles. Its interaction with the cytoplasmic domains of some p24-family members, type I transmembrane proteins of the Golgi, has been shown to induce a conformational change of coatomer that initiates polymerization of the complex. From stoichiometrical data it is likely that interaction of coatomer with the small tail domains involves an oligomeric form of the p24 proteins. Here we present the structure of peptide analogs of the cytoplasmic domain of p23, a member of the p24 family, as determined by two-dimensional nuclear magnetic resonance spectroscopy in the presence of 2,2,2-trifluoroethanol. An improved strategy for structure calculation revealed that the tail domain peptides form alpha-helices and adopt a tetrameric state. Based on these results we propose an initial model for the binding of coatomer by p23 and the induced conformational change of coatomer that results in its polymerization, curvature of the Golgi membrane to form a bud, and finally a COPI-coated vesicle.
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Affiliation(s)
- M Weidler
- Lehrstuhl für Biopolymere, Universität Bayreuth, Germany.
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27
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Simon JP, Ivanov IE, Adesnik M, Sabatini DD. In vitro generation from the trans-Golgi network of coatomer-coated vesicles containing sialylated vesicular stomatitis virus-G protein. Methods 2000; 20:437-54. [PMID: 10720465 DOI: 10.1006/meth.2000.0957] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We describe an in vitro system in which post-Golgi vesicles containing metabolically labeled, sialylated, vesicular stomatitis virus (VSV) G protein molecules (VSV-G) are produced from the trans-Golgi network (TGN) of an isolated Golgi membrane fraction. This fraction is prepared from VSV-infected Madin-Darby canine kidney (MDCK) cells in which the (35)S-labeled viral envelope glycoprotein was allowed to accumulate in the trans-Golgi network during a prolonged incubation at 20 degrees C. The vesicles produced in this system are separated from the remnant Golgi membranes by differential centrifugation or by velocity sedimentation in a sucrose gradient. Vesicle production, quantified as the percentage of labeled VSV-G released from the Golgi membranes, is optimal at 37 degrees C and does not occur below 20 degrees C. It requires GTP and the small GTP-binding protein Arf (ADP-ribosylation factor), as well as coat protein type I (COPI) coat components (coatomer) and vesicle scission factors-one of which corresponds to the phosphatidylinositol transfer protein (PITP). Formation of the vesicles does not require GTP hydrolysis which, however, is necessary for their uncoating. Thus, vesicles generated in the presence of the nonhydrolyzable GTP analogs, GTPgammaS or GMP-PNP, retain a coatomer coat visible in the electron microscope, sediment more rapidly in sucrose density gradients than those generated with ATP or GTP, and can be captured with anticoatomerantibodies. The process of coatomer-coated vesicle formation from the TGN can be dissected into two distinct sequential phases, corresponding to coat assembly/bud formation and vesicle scission. The first phase is completed when Golgi fractions are incubated with cytosolic proteins and nonhydrolyzable GTP analogs at 20 degrees C. The scission phase, which leads to vesicle release, takes place when coated Golgi membranes, recovered after phase I, are incubated at higher temperatures in the presence of cytosolic proteins. The scission phase does not take place if protein kinase C inhibitors are added during the first phase, even though these inhibitors do not prevent membrane coating and bud formation. The phosphorylating activity of a protein kinase C, however, plays no role in vesicle formation, since this process does not require ATP.
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Affiliation(s)
- J P Simon
- Department of Cell Biology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
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Abstract
Endoplasmic reticulum (ER)-to-Golgi traffic in yeast proceeds by the maturation of membrane compartments from post-ER vesicles to intermediate small vesicle tubular clusters (VTCs) to Golgi nodular membrane networks (Morin-Ganet et al., Traffic 2000; 1: 56-68). The balance between ER and Golgi compartments is maintained by COPII- and COPI-mediated anterograde and retrograde traffic, which are dependent on Sec7p and ARF function. The sec7-4 temperature-sensitive allele is a mutation in the highly conserved Sec7 domain (Sec7d) found in all ARF-guanine nucleotide exchange factor proteins. Post-ER trafficking is rapidly inactivated in sec7-4 mutant yeast at the restrictive temperature. This conditional defect prevented the normal production of VTCs and instead generated Golgi-like tubes emanating from the ER exit sites. These tubes progressively developed into stacked cisternae defining the landmark sec7 mutant phenotype. Consistent with the in vivo results, a Sec7d peptide inhibited ER-to-Golgi transport and displaced Sec7p from its membrane anchor in vitro. The similarities in the consequences of inactivating Sec7p or ARFs in vivo was revealed by genetic disruption of yeast ARFs or by addition of brefeldin A (BFA) to whole cells. These treatments, as in sec7-4 yeast, affected the morphology of membrane compartments in the ER-Golgi transition. Further evidence for Sec7p involvement in the transition for Golgi biogenesis was revealed by in vitro binding between distinct domains of Sec7p with ARFs, COPI and COPII coat proteins. These results suggest that Sec7p coordinates membrane transitions in Golgi biogenesis by directing and scaffolding the binding and disassembly of coat protein complexes to membranes, both at the VTC transition from ER exit sites to form Golgi elements and for later events in Golgi maturation.
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Affiliation(s)
- S B Deitz
- Program in Molecular Biology and CU Cancer Center, Department of Cellular and Structural Biology, Box B-111, University of Colorado Health Sciences Center, Denver, CO 80262, USA
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