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Makhoul C, Gosavi P, Duffield R, Delbridge B, Williamson NA, Gleeson PA. Intersectin-1 interacts with the golgin GCC88 to couple the actin network and Golgi architecture. Mol Biol Cell 2019; 30:370-386. [PMID: 30540523 PMCID: PMC6589577 DOI: 10.1091/mbc.e18-05-0313] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 11/19/2018] [Accepted: 12/04/2018] [Indexed: 12/19/2022] Open
Abstract
The maintenance of the Golgi ribbon relies on a dynamic balance between the actin and microtubule networks; however, the pathways controlling actin networks remain poorly defined. Previously, we showed that the trans-Golgi network (TGN) membrane tether/golgin, GCC88, modulates the Golgi ribbon architecture. Here, we show that dispersal of the Golgi ribbon by GCC88 is dependent on actin and the involvement of nonmuscle myosin IIA. We have identified the long isoform of intersectin-1 (ITSN-1), a guanine nucleotide exchange factor for Cdc42, as a novel Golgi component and an interaction partner of GCC88 responsible for mediating the actin-dependent dispersal of the Golgi ribbon. We show that perturbation of Golgi morphology by changes in membrane flux, mediated by silencing the retromer subunit Vps26, or in a model of neurodegeneration, induced by Tau overexpression, are also dependent on the ITSN-1-GCC88 interaction. Overall, our study reveals a role for a TGN golgin and ITSN-1 in linking to the actin cytoskeleton and regulating the balance between a compact Golgi ribbon and a dispersed Golgi, a pathway with relevance to pathophysiological conditions.
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Affiliation(s)
- Christian Makhoul
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Prajakta Gosavi
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Regina Duffield
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Bronwen Delbridge
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Nicholas A. Williamson
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Paul A. Gleeson
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
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Chauhan AS, Kumar M, Chaudhary S, Dhiman A, Patidar A, Jakhar P, Jaswal P, Sharma K, Sheokand N, Malhotra H, Raje CI, Raje M. Trafficking of a multifunctional protein by endosomal microautophagy: linking two independent unconventional secretory pathways. FASEB J 2019; 33:5626-5640. [PMID: 30640524 DOI: 10.1096/fj.201802102r] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
During physiologic stresses, like micronutrient starvation, infection, and cancer, the cytosolic moonlighting protein glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is trafficked to the plasma membrane (PM) and extracellular milieu (ECM). Our work demonstrates that GAPDH mobilized to the PM, and the ECM does not utilize the classic endoplasmic reticulum-Golgi route of secretion; instead, it is first selectively translocated into early and late endosomes from the cytosol via microautophagy. GAPDH recruited to this common entry point is subsequently delivered into multivesicular bodies, leading to its membrane trafficking through secretion via exosomes and secretory lysosomes. We present evidence that both pathways of GAPDH membrane trafficking are up-regulated upon iron starvation, potentially by mobilization of intracellular calcium. These pathways also play a role in clearance of misfolded intracellular polypeptide aggregates. Our findings suggest that cells build in redundancy for vital cellular pathways to maintain micronutrient homeostasis and prevent buildup of toxic intracellular misfolded protein refuse.-Chauhan, A. S., Kumar, M., Chaudhary, S., Dhiman, A., Patidar, A., Jakhar, P., Jaswal, P., Sharma, K., Sheokand, N., Malhotra, H., Raje, C. I., Raje. M. Trafficking of a multifunctional protein by endosomal microautophagy: linking two independent unconventional secretory pathways.
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Affiliation(s)
- Anoop Singh Chauhan
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, India
| | - Manoj Kumar
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, India
| | - Surbhi Chaudhary
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, India
| | - Asmita Dhiman
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, India
| | - Anil Patidar
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, India
| | - Priyanka Jakhar
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, India
| | - Pallavi Jaswal
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, India
| | - Kapil Sharma
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, India
| | - Navdeep Sheokand
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, India
| | - Himanshu Malhotra
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, India
| | | | - Manoj Raje
- Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, India
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Abstract
The Golgi apparatus is a central intracellular membrane-bound organelle with key functions in trafficking, processing, and sorting of newly synthesized membrane and secretory proteins and lipids. To best perform these functions, Golgi membranes form a unique stacked structure. The Golgi structure is dynamic but tightly regulated; it undergoes rapid disassembly and reassembly during the cell cycle of mammalian cells and is disrupted under certain stress and pathological conditions. In the past decade, significant amount of effort has been made to reveal the molecular mechanisms that regulate the Golgi membrane architecture and function. Here we review the major discoveries in the mechanisms of Golgi structure formation, regulation, and alteration in relation to its functions in physiological and pathological conditions to further our understanding of Golgi structure and function in health and diseases.
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Affiliation(s)
- Jie Li
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Erpan Ahat
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Yanzhuang Wang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
- Department of Neurology, University of Michigan School of Medicine, Ann Arbor, MI, USA.
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54
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The Golgi architecture and cell sensing. Biochem Soc Trans 2018; 46:1063-1072. [DOI: 10.1042/bst20180323] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 08/06/2018] [Accepted: 08/21/2018] [Indexed: 12/23/2022]
Abstract
An array of signalling molecules are located at the Golgi apparatus, including phosphoinositides, small GTPases, kinases, and phosphatases, which are linked to multiple signalling pathways. Initially considered to be associated predominantly with membrane trafficking, signalling pathways at the Golgi are now recognised to regulate a diverse range of higher-order functions. Many of these signalling pathways are influenced by the architecture of the Golgi. In vertebrate cells, the Golgi consists of individual stacks fused together into a compact ribbon structure and the function of this ribbon structure has been enigmatic. Notably, recent advances have identified a role for the Golgi ribbon in regulation of cellular processes. Fragmentation of the Golgi ribbon results in modulation of many signalling pathways. Various diseases and disorders, including cancer and neurodegeneration, are associated with the loss of the Golgi ribbon and the appearance of a dispersed fragmented Golgi. Here, we review the emerging theme of the Golgi as a cell sensor and highlight the relationship between the morphological status of the Golgi in vertebrate cells and the modulation of signalling networks.
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55
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Serebrenik YV, Hellerschmied D, Toure M, López-Giráldez F, Brookner D, Crews CM. Targeted protein unfolding uncovers a Golgi-specific transcriptional stress response. Mol Biol Cell 2018; 29:1284-1298. [PMID: 29851555 PMCID: PMC5994893 DOI: 10.1091/mbc.e17-11-0693] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 03/26/2018] [Accepted: 03/30/2018] [Indexed: 12/12/2022] Open
Abstract
In eukaryotic cells, organelle-specific stress-response mechanisms are vital for maintaining cellular homeostasis. The Golgi apparatus, an essential organelle of the secretory system, is the major site of protein modification and sorting within a cell and functions as a platform for spatially regulated signaling. Golgi homeostasis mechanisms that regulate organelle structure and ensure precise processing and localization of protein substrates remain poorly understood. Using a chemical biology strategy to induce protein unfolding, we uncover a Golgi-specific transcriptional response. An RNA-sequencing profile of this stress response compared with the current state-of-the-art Golgi stressors, nigericin and xyloside, demonstrates the enhanced precision of Golgi targeting achieved with our system. The data set further reveals previously uncharacterized genes that we find to be essential for Golgi structural integrity. These findings highlight the Golgi's ability to sense misfolded proteins and establish new aspects of Golgi autoregulation.
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Affiliation(s)
- Yevgeniy V. Serebrenik
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511
| | - Doris Hellerschmied
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511
| | - Momar Toure
- Department of Chemistry, Yale University, New Haven, CT 06511
| | | | - Dennis Brookner
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511
| | - Craig M. Crews
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511
- Department of Chemistry, Yale University, New Haven, CT 06511
- Department of Pharmacology, Yale University, New Haven, CT 06511
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56
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van Leeuwen W, van der Krift F, Rabouille C. Modulation of the secretory pathway by amino-acid starvation. J Cell Biol 2018; 217:2261-2271. [PMID: 29669743 PMCID: PMC6028531 DOI: 10.1083/jcb.201802003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/28/2018] [Accepted: 03/29/2018] [Indexed: 12/30/2022] Open
Abstract
As a major anabolic pathway, the secretory pathway needs to adapt to the demands of the surrounding environment and responds to different exogenous signals and stimuli. In this context, the transport in the early secretory pathway from the endoplasmic reticulum (ER) to the Golgi apparatus appears particularly regulated. For instance, protein export from the ER is critically stimulated by growth factors. Conversely, nutrient starvation also modulates functions of the early secretory pathway in multiple ways. In this review, we focus on amino-acid starvation and how the function of the early secretory pathway is redirected to fuel autophagy, how the ER exit sites are remodeled into novel cytoprotective stress assemblies, and how secretion is modulated in vivo in starving organisms. With the increasingly exciting knowledge on mechanistic target of rapamycin complex 1 (mTORC1), the major nutrient sensor, it is also a good moment to establish how the modulation of the secretory pathway by amino-acid restriction intersects with this major signaling hub.
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Affiliation(s)
- Wessel van Leeuwen
- Hubrecht Institute of the Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Utrecht, Netherlands
| | - Felix van der Krift
- Hubrecht Institute of the Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Utrecht, Netherlands
| | - Catherine Rabouille
- Hubrecht Institute of the Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Utrecht, Netherlands .,Department of Cell Biology, University Medical Center Groningen, Groningen, Netherlands
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57
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Avwioroko OJ, Anigboro AA, Unachukwu NN, Tonukari NJ. Isolation, identification and in silico analysis of alpha-amylase gene of Aspergillus niger strain CSA35 obtained from cassava undergoing spoilage. Biochem Biophys Rep 2018; 14:35-42. [PMID: 29872732 PMCID: PMC5986626 DOI: 10.1016/j.bbrep.2018.03.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 03/26/2018] [Accepted: 03/27/2018] [Indexed: 11/19/2022] Open
Abstract
In this investigation, a gene (CDF_Amyl) encoding extracellular α-amylase in Aspergillus niger strain CSA35 associated with cassava spoilage was amplified using specific primers and characterized in silico. The gene had a partial nucleotide sequence of 968 bp and encoded a protein of 222 aa residues with a molecular weight and isoelectric point of 25.13 kDa and 4.17, respectively. Its catalytic site was located in the active site domain. BLASTp analysis showed that the protein primary sequence of the α-amylase gene had 98% and 99% homologies with the α-amylase of A. niger and A. oryzae RIB40, respectively. The gene is more closely related to α-amylase genes from fungi than to bacterial, plant, or animal α-amylase genes. Restriction mapping of the gene showed it can be digested with restriction enzymes like NcoI, PstI, SmaI, and BcLI among others but not with EcoRI and EcoRV. Its protein product had a hydrophobicity score of - 0.43 but no transmembrane helix. The CDF_Amyl protein was subcellularly localized in the secretory pathway, an indication of its release into extracellular space after secretion. Also, the 3D structure of the CDF-Amyl protein was barrel-shaped with domains characteristic of α-amylases. The encoded α-amylase Vmax is 6.90 U/mg protein and Km is 6.70 mg/ml. It was concluded that the unique characteristics of the CDF_Amyl gene and its deduced protein could find applications in biotechnological, food and pharmaceutical industries where cloning and further modification of this gene would be required for product development and improvement.
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Affiliation(s)
- Oghenetega J. Avwioroko
- Biochemistry Division, Department of Chemical Sciences, College of Natural Sciences, Redeemer's University, Ede, Osun State, Nigeria
- Corresponding author.
| | - Akpovwehwee A. Anigboro
- Department of Biochemistry, Faculty of Science, Delta State University, P.M.B. 1, Abraka, Nigeria
| | - Nnanna N. Unachukwu
- Bioscience Center, International Institute for Tropical Agriculture (IITA), Ibadan, Oyo State, Nigeria
| | - Nyerhovwo J. Tonukari
- Department of Biochemistry, Faculty of Science, Delta State University, P.M.B. 1, Abraka, Nigeria
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58
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Baumann J, Ignashkova TI, Chirasani SR, Ramírez-Peinado S, Alborzinia H, Gendarme M, Kuhnigk K, Kramer V, Lindemann RK, Reiling JH. Golgi stress-induced transcriptional changes mediated by MAPK signaling and three ETS transcription factors regulate MCL1 splicing. Mol Biol Cell 2018; 29:42-52. [PMID: 29118074 PMCID: PMC5746065 DOI: 10.1091/mbc.e17-06-0418] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 10/11/2017] [Accepted: 10/31/2017] [Indexed: 12/14/2022] Open
Abstract
The secretory pathway is a major determinant of cellular homoeostasis. While research into secretory stress signaling has so far mostly focused on the endoplasmic reticulum (ER), emerging data suggest that the Golgi itself serves as an important signaling hub capable of initiating stress responses. To systematically identify novel Golgi stress mediators, we performed a transcriptomic analysis of cells exposed to three different pharmacological compounds known to elicit Golgi fragmentation: brefeldin A, golgicide A, and monensin. Subsequent gene-set enrichment analysis revealed a significant contribution of the ETS family transcription factors ELK1, GABPA/B, and ETS1 to the control of gene expression following compound treatment. Induction of Golgi stress leads to a late activation of the ETS upstream kinases MEK1/2 and ERK1/2, resulting in enhanced ETS factor activity and the transcription of ETS family target genes related to spliceosome function and cell death induction via alternate MCL1 splicing. Further genetic analyses using loss-of-function and gain-of-function experiments suggest that these transcription factors operate in parallel.
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Affiliation(s)
- Jan Baumann
- BioMed X Innovation Center, 69120 Heidelberg, Germany
| | | | | | | | | | | | - Kyra Kuhnigk
- BioMed X Innovation Center, 69120 Heidelberg, Germany
| | | | - Ralph K Lindemann
- Translational Innovation Platform Oncology, Merck Biopharma, Merck KGaA, 64293 Darmstadt, Germany
| | - Jan H Reiling
- BioMed X Innovation Center, 69120 Heidelberg, Germany
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59
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Wisse LE, Penning R, Zaal EA, van Berkel CGM, Ter Braak TJ, Polder E, Kenney JW, Proud CG, Berkers CR, Altelaar MAF, Speijer D, van der Knaap MS, Abbink TEM. Proteomic and Metabolomic Analyses of Vanishing White Matter Mouse Astrocytes Reveal Deregulation of ER Functions. Front Cell Neurosci 2017; 11:411. [PMID: 29375313 PMCID: PMC5770689 DOI: 10.3389/fncel.2017.00411] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 12/07/2017] [Indexed: 12/20/2022] Open
Abstract
Vanishing white matter (VWM) is a leukodystrophy with predominantly early-childhood onset. Affected children display various neurological signs, including ataxia and spasticity, and die early. VWM patients have bi-allelic mutations in any of the five genes encoding the subunits of the eukaryotic translation factor 2B (eIF2B). eIF2B regulates protein synthesis rates under basal and cellular stress conditions. The underlying molecular mechanism of how mutations in eIF2B result in VWM is unknown. Previous studies suggest that brain white matter astrocytes are primarily affected in VWM. We hypothesized that the translation rate of certain astrocytic mRNAs is affected by the mutations, resulting in astrocytic dysfunction. Here we subjected primary astrocyte cultures of wild type (wt) and VWM (2b5ho) mice to pulsed labeling proteomics based on stable isotope labeling with amino acids in cell culture (SILAC) with an L-azidohomoalanine (AHA) pulse to select newly synthesized proteins. AHA was incorporated into newly synthesized proteins in wt and 2b5ho astrocytes with similar efficiency, without affecting cell viability. We quantified proteins synthesized in astrocytes of wt and 2b5ho mice. This proteomic profiling identified a total of 80 proteins that were regulated by the eIF2B mutation. We confirmed increased expression of PROS1 in 2b5ho astrocytes and brain. A DAVID enrichment analysis showed that approximately 50% of the eIF2B-regulated proteins used the secretory pathway. A small-scale metabolic screen further highlighted a significant change in the metabolite 6-phospho-gluconate, indicative of an altered flux through the pentose phosphate pathway (PPP). Some of the proteins migrating through the secretory pathway undergo oxidative folding reactions in the endoplasmic reticulum (ER), which produces reactive oxygen species (ROS). The PPP produces NADPH to remove ROS. The proteomic and metabolomics data together suggest a deregulation of ER function in 2b5ho mouse astrocytes.
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Affiliation(s)
- Lisanne E Wisse
- Pediatrics, VU University Medical Center, Amsterdam, Netherlands
| | - Renske Penning
- Biomolecular Mass Spectrometry and Proteomics Group, Utrecht Institute for Pharmaceutical Sciences, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | - Esther A Zaal
- Biomolecular Mass Spectrometry and Proteomics Group, Utrecht Institute for Pharmaceutical Sciences, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | | | - Timo J Ter Braak
- Pediatrics, VU University Medical Center, Amsterdam, Netherlands
| | - Emiel Polder
- Pediatrics, VU University Medical Center, Amsterdam, Netherlands
| | - Justin W Kenney
- Centre for Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Christopher G Proud
- Centre for Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Celia R Berkers
- Biomolecular Mass Spectrometry and Proteomics Group, Utrecht Institute for Pharmaceutical Sciences, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | - Maarten A F Altelaar
- Biomolecular Mass Spectrometry and Proteomics Group, Utrecht Institute for Pharmaceutical Sciences, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands
| | - Dave Speijer
- Medical Biochemistry, Academic Medical Center, Amsterdam, Netherlands
| | | | - Truus E M Abbink
- Pediatrics, VU University Medical Center, Amsterdam, Netherlands
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60
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Stevenson NL, Bergen DJM, Skinner REH, Kague E, Martin-Silverstone E, Robson Brown KA, Hammond CL, Stephens DJ. Giantin-knockout models reveal a feedback loop between Golgi function and glycosyltransferase expression. J Cell Sci 2017; 130:4132-4143. [PMID: 29093022 PMCID: PMC5769581 DOI: 10.1242/jcs.212308] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 10/21/2017] [Indexed: 12/14/2022] Open
Abstract
The Golgi is the cellular hub for complex glycosylation, controlling accurate processing of complex proteoglycans, receptors, ligands and glycolipids. Its structure and organisation are dependent on golgins, which tether cisternal membranes and incoming transport vesicles. Here, we show that knockout of the largest golgin, giantin, leads to substantial changes in gene expression but only limited effects on Golgi structure. Notably, 22 Golgi-resident glycosyltransferases, but not glycan-processing enzymes or the ER glycosylation machinery, are differentially expressed following giantin ablation. This includes near-complete loss of function of GALNT3 in both mammalian cell and zebrafish models. Giantin-knockout zebrafish exhibit hyperostosis and ectopic calcium deposits, recapitulating phenotypes of hyperphosphatemic familial tumoral calcinosis, a disease caused by mutations in GALNT3. These data reveal a new feature of Golgi homeostasis: the ability to regulate glycosyltransferase expression to generate a functional proteoglycome.
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Affiliation(s)
- Nicola L Stevenson
- Cell Biology Laboratories, School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Dylan J M Bergen
- Cell Biology Laboratories, School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Roderick E H Skinner
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Erika Kague
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Elizabeth Martin-Silverstone
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Kate A Robson Brown
- Computed Tomography Laboratory, School of Arts, University of Bristol, 43 Woodland Road, Bristol BS8 1UU, UK
| | - Chrissy L Hammond
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - David J Stephens
- Cell Biology Laboratories, School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
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61
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Influenza A Virus M2 Protein: Roles from Ingress to Egress. Int J Mol Sci 2017; 18:ijms18122649. [PMID: 29215568 PMCID: PMC5751251 DOI: 10.3390/ijms18122649] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 12/04/2017] [Accepted: 12/05/2017] [Indexed: 11/17/2022] Open
Abstract
Influenza A virus (IAV) matrix protein 2 (M2) is among the smallest bona fide, hence extensively studied, ion channel proteins. The M2 ion channel activity is not only essential for virus replication, but also involved in modulation of cellular homeostasis in a variety of ways. It is also the target for ion channel inhibitors, i.e., anti-influenza drugs. Thus far, several studies have been conducted to elucidate its biophysical characteristics, structure-function relationships of the ion channel, and the M2-host interactome. In this review, we discuss M2 protein synthesis and assembly into an ion channel, its roles in IAV replication, and the pathophysiological impact on the host cell.
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62
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Kang JH, Kim HJ, Park MK, Lee CH. Sphingosylphosphorylcholine Induces Thrombospondin-1 Secretion in MCF10A Cells via ERK2. Biomol Ther (Seoul) 2017; 25:625-633. [PMID: 28274095 PMCID: PMC5685432 DOI: 10.4062/biomolther.2016.228] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 12/11/2016] [Accepted: 01/09/2017] [Indexed: 01/06/2023] Open
Abstract
Sphingosylphosphorylcholine (SPC) is one of the bioactive phospholipids that has many cellular functions such as cell migration, adhesion, proliferation, angiogenesis, and Ca²⁺ signaling. Recent studies have reported that SPC induces invasion of breast cancer cells via matrix metalloproteinase-3 (MMP-3) secretion leading to WNT activation. Thrombospondin-1 (TSP-1) is a matricellular and calcium-binding protein that binds to a wide variety of integrin and non-integrin cell surface receptors. It regulates cell proliferation, migration, and apoptosis in inflammation, angiogenesis and neoplasia. TSP-1 promotes aggressive phenotype via epithelial mesenchymal transition (EMT). The relationship between SPC and TSP-1 is unclear. We found SPC induced EMT leading to mesenchymal morphology, decrease of E-cadherin expression and increases of N-cadherin and vimentin. SPC induced secretion of thrombospondin-1 (TSP-1) during SPC-induced EMT of various breast cancer cells. Gene silencing of TSP-1 suppressed SPC-induced EMT as well as migration and invasion of MCF10A cells. An extracellular signal-regulated kinase inhibitor, PD98059, significantly suppressed the secretion of TSP-1, expressions of N-cadherin and vimentin, and decrease of E-cadherin in MCF10A cells. ERK2 siRNA suppressed TSP-1 secretion and EMT. From online PROGgene V2, relapse free survival is low in patients having high TSP-1 expressed breast cancer. Taken together, we found that SPC induced EMT and TSP-1 secretion via ERK2 signaling pathway. These results suggests that SPC-induced TSP-1 might be a new target for suppression of metastasis of breast cancer cells.
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Affiliation(s)
- June Hee Kang
- College of Pharmacy, Dongguk University, Seoul 10326, Republic of Korea
| | - Hyun Ji Kim
- College of Pharmacy, Dongguk University, Seoul 10326, Republic of Korea
| | - Mi Kyung Park
- College of Pharmacy, Dongguk University, Seoul 10326, Republic of Korea.,National Cancer Center, Goyang, 10408, Republic of Korea
| | - Chang Hoon Lee
- College of Pharmacy, Dongguk University, Seoul 10326, Republic of Korea
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63
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Gosavi P, Gleeson PA. The Function of the Golgi Ribbon Structure - An Enduring Mystery Unfolds! Bioessays 2017; 39. [PMID: 28984991 DOI: 10.1002/bies.201700063] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 08/31/2017] [Indexed: 12/13/2022]
Abstract
The Golgi apparatus in vertebrate cells consists of individual Golgi stacks fused together in a continuous ribbon structure. The ribbon structure per se is not required to mediate the classical functions of this organelle and the relevance of the "ribbon" structure has been a mystery since first identified ultrastructurally in the 1950s. Recent advances recognize a role for the Golgi apparatus in a range of cellular processes, some mediated by signaling networks which are regulated at the Golgi. Here we review the cellular processes and signaling events regulated by the Golgi apparatus and, in particular, explore an emerging theme that the ribbon structure of the Golgi contributes directly to the regulation of these higher order functions.
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Affiliation(s)
- Prajakta Gosavi
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, 3010, Australia
| | - Paul A Gleeson
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, 3010, Australia
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64
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Chabanon M, Stachowiak JC, Rangamani P. Systems biology of cellular membranes: a convergence with biophysics. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2017; 9. [PMID: 28475297 PMCID: PMC5561455 DOI: 10.1002/wsbm.1386] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 02/02/2017] [Accepted: 02/21/2017] [Indexed: 12/12/2022]
Abstract
Systems biology and systems medicine have played an important role in the last two decades in shaping our understanding of biological processes. While systems biology is synonymous with network maps and '-omics' approaches, it is not often associated with mechanical processes. Here, we make the case for considering the mechanical and geometrical aspects of biological membranes as a key step in pushing the frontiers of systems biology of cellular membranes forward. We begin by introducing the basic components of cellular membranes, and highlight their dynamical aspects. We then survey the functions of the plasma membrane and the endomembrane system in signaling, and discuss the role and origin of membrane curvature in these diverse cellular processes. We further give an overview of the experimental and modeling approaches to study membrane phenomena. We close with a perspective on the converging futures of systems biology and membrane biophysics, invoking the need to include physical variables such as location and geometry in the study of cellular membranes. WIREs Syst Biol Med 2017, 9:e1386. doi: 10.1002/wsbm.1386 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Morgan Chabanon
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, USA
| | - Jeanne C Stachowiak
- Department of Biomedical Engineering, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, USA
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, USA
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65
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Ravasio V, Damiati E, Zizioli D, Orizio F, Giacopuzzi E, Manzoni M, Bresciani R, Borsani G, Monti E. Genomic and biochemical characterization of sialic acid acetylesterase (siae) in zebrafish. Glycobiology 2017; 27:938-946. [DOI: 10.1093/glycob/cwx068] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 07/21/2017] [Indexed: 01/08/2023] Open
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66
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Cheng L, Fan K, Huang Y, Wang D, Leung KS. Full Characterization of Localization Diversity in the Human Protein Interactome. J Proteome Res 2017; 16:3019-3029. [DOI: 10.1021/acs.jproteome.7b00306] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Lixin Cheng
- Department
of Computer Science and Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Kaili Fan
- College
of Bioinformatics Science and Technology, Harbin Medical University, Harbin, China
| | - Yan Huang
- College
of Bioinformatics Science and Technology, Harbin Medical University, Harbin, China
| | - Dong Wang
- College
of Bioinformatics Science and Technology, Harbin Medical University, Harbin, China
- Center
for Informational Biology, University of Electronic Science and Technology of China, Chengdu, China
| | - Kwong-Sak Leung
- Department
of Computer Science and Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
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67
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Ignashkova TI, Gendarme M, Peschk K, Eggenweiler HM, Lindemann RK, Reiling JH. Cell survival and protein secretion associated with Golgi integrity in response to Golgi stress-inducing agents. Traffic 2017; 18:530-544. [PMID: 28485883 DOI: 10.1111/tra.12493] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 05/05/2017] [Accepted: 05/05/2017] [Indexed: 12/29/2022]
Abstract
The Golgi apparatus is part of the secretory pathway and of central importance for modification, transport and sorting of proteins and lipids. ADP-ribosylation factors, whose activation can be blocked by brefeldin A (BFA), play a major role in functioning of the Golgi network and regulation of membrane traffic and are also involved in proliferation and migration of cancer cells. Due to high cytotoxicity and poor bioavailability, BFA has not passed the preclinical stage of drug development. Recently, AMF-26 and golgicide A have been described as novel inhibitors of the Golgi system with antitumor or bactericidal properties. We provide here further evidence that AMF-26 closely mirrors the mode of action of BFA but is less potent. Using several human cancer cell lines, we studied the effects of AMF-26, BFA and golgicide A on cell homeostasis including Golgi structure, endoplasmic reticulum (ER) stress markers, secretion and viability, and found overall a significant correlation between these parameters. Furthermore, modulation of ADP-ribosylation factor expression has a profound impact on Golgi organization and survival in response to Golgi stress inducers.
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Affiliation(s)
- Tatiana I Ignashkova
- Metabolism and Signaling in Cancer, BioMed X Innovation Center, Heidelberg, Germany
| | - Mathieu Gendarme
- Metabolism and Signaling in Cancer, BioMed X Innovation Center, Heidelberg, Germany
| | - Katrin Peschk
- Medicinal Chemistry, Merck Biopharma, Merck KGaA, Darmstadt, Germany
| | | | - Ralph K Lindemann
- Translational Innovation Platform Oncology, Merck Biopharma, Merck KGaA, Darmstadt, Germany
| | - Jan H Reiling
- Metabolism and Signaling in Cancer, BioMed X Innovation Center, Heidelberg, Germany
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68
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Duclos C, Lavoie C, Denault JB. Caspases rule the intracellular trafficking cartel. FEBS J 2017; 284:1394-1420. [PMID: 28371378 DOI: 10.1111/febs.14071] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 03/17/2017] [Accepted: 03/27/2017] [Indexed: 12/15/2022]
Abstract
During apoptosis, caspases feast on several hundreds of cellular proteins to orchestrate rapid cellular demise. Indeed, caspases are known to get a taste of every cellular process in one way or another, activating some, but most often shutting them down. Thus, it is not surprising that caspases proteolyze proteins involved in intracellular trafficking with particularly devastating consequences for this important process. This review article focuses on how caspases target the machinery responsible for smuggling goods within and outside the cell.
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Affiliation(s)
- Catherine Duclos
- Institut de Pharmacologie de Sherbrooke, Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, QC, Canada
| | - Christine Lavoie
- Institut de Pharmacologie de Sherbrooke, Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, QC, Canada
| | - Jean-Bernard Denault
- Institut de Pharmacologie de Sherbrooke, Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, QC, Canada
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69
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Wei JH, Seemann J. Golgi ribbon disassembly during mitosis, differentiation and disease progression. Curr Opin Cell Biol 2017; 47:43-51. [PMID: 28390244 DOI: 10.1016/j.ceb.2017.03.008] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 03/07/2017] [Accepted: 03/08/2017] [Indexed: 11/16/2022]
Abstract
The Golgi apparatus is tightly integrated into the cellular system where it plays essential roles required for a variety of cellular processes. Its vital functions include not only processing and sorting of proteins and lipids, but also serving as a signaling hub and a microtubule-organizing center. Golgi stacks in mammalian cells are interconnected into a compact ribbon in the perinuclear region. However, the ribbon can undergo distinct disassembly processes that reflect the cellular state or environmental demands and stress. For instance, its most dramatic change takes place in mitosis when the ribbon is efficiently disassembled into vesicles through a combination of ribbon unlinking, cisternal unstacking and vesiculation. Furthermore, the ribbon can also be detached and positioned at specific cellular locations to gain additional functionalities during differentiation, or fragmented to different degrees along disease progression or upon cell death. Here, we describe the major morphological alterations of Golgi ribbon disassembly under physiological and pathological conditions and discuss the underlying mechanisms that drive these changes.
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Affiliation(s)
- Jen-Hsuan Wei
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Joachim Seemann
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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70
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Aguilera-Gomez A, Rabouille C. Membrane-bound organelles versus membrane-less compartments and their control of anabolic pathways in Drosophila. Dev Biol 2017; 428:310-317. [PMID: 28377034 DOI: 10.1016/j.ydbio.2017.03.029] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 03/27/2017] [Accepted: 03/27/2017] [Indexed: 12/29/2022]
Abstract
Classically, we think of cell compartmentalization as being achieved by membrane-bound organelles. It has nevertheless emerged that membrane-less assemblies also largely contribute to this compartmentalization. Here, we compare the characteristics of both types of compartmentalization in term of maintenance of functional identities. Furthermore, membrane less-compartments are critical for sustaining developmental and cell biological events as they control major metabolic pathways. We describe two examples related to this issue in Drosophila, the role of P-bodies in the translational control of gurken in the Drosophila oocyte, and the formation of Sec bodies upon amino-acid starvation in Drosophila cells.
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Affiliation(s)
| | - Catherine Rabouille
- Hubrecht Institute of the KNAW & UMC Utrecht, 3584 CT Utrecht, The Netherlands; Department of Cell Biology, UMC Utrecht, The Netherlands; Department of Cell Biology, UMC Groningen, The Netherlands.
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71
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Lee H, Min K, Yi JS, Shi H, Chang W, Jackson L, Bennett AM. A Phosphoproteomic Screen Identifies a Guanine Nucleotide Exchange Factor for Rab3A Protein as a Mitogen-activated Protein (MAP) Kinase Phosphatase-5-regulated MAP Kinase Target in Interleukin 6 (IL-6) Secretion and Myogenesis. J Biol Chem 2017; 292:3581-3590. [PMID: 28096466 DOI: 10.1074/jbc.m116.769208] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/13/2017] [Indexed: 11/06/2022] Open
Abstract
The mitogen-activated protein kinases (MAPKs) have been shown to regulate skeletal muscle function. Previously, we showed that MAPK phosphatase-5 (MKP-5) negatively regulates myogenesis and regeneration of skeletal muscle through inhibition of p38 MAPK and c-Jun N-terminal kinase (JNK). However, the identity and contribution of MKP-5-regulated MAPK targets in the control of skeletal muscle function and regenerative myogenesis have not been established. To identify MKP-5-regulated MAPK substrates in skeletal muscle, we performed a global differential phospho-MAPK substrate screen in regenerating skeletal muscles of wild type and MKP-5-deficient mice. We discovered a novel MKP-5-regulated MAPK substrate called guanine nucleotide exchange factor for Rab3A (GRAB) that was hyperphosphorylated on a phospho-MAPK motif in skeletal muscle of MKP-5-deficient mice. GRAB was found to be phosphorylated by JNK on serine 169. Myoblasts overexpressing a phosphorylation-defective mutant of GRAB containing a mutation at Ser-169 to Ala-169 (GRAB-S169A) inhibited the ability of C2C12 myoblasts to differentiate. We found that GRAB phosphorylation at Ser-169 was required for the secretion of the promyogenic cytokine interleukin 6 (IL-6). Consistent with this observation, MKP-5-deficient mice exhibited increased circulating IL-6 expression as compared with wild type mice. Collectively, these data demonstrate a novel mechanism whereby MKP-5-mediated regulation of JNK negatively regulates phosphorylation of GRAB, which subsequently controls secretion of IL-6. These data support the notion that MKP-5 serves as a negative regulator of MAPK-dependent signaling of critical skeletal muscle signaling pathways.
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Affiliation(s)
- Hojin Lee
- From the Department of Pharmacology and
| | - Kisuk Min
- From the Department of Pharmacology and
| | | | - Hao Shi
- the Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060
| | - Woochul Chang
- the Department of Biology Education, College of Education, Pusan National University, Busan 609-735, Republic of Korea, and
| | - Leandra Jackson
- Program in Public Health, University of California, Irvine, California 92697
| | - Anton M Bennett
- From the Department of Pharmacology and .,Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University, New Haven, Connecticut 06520
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72
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Ayala I, Colanzi A. Alterations of Golgi organization in Alzheimer's disease: A cause or a consequence? Tissue Cell 2016; 49:133-140. [PMID: 27894594 DOI: 10.1016/j.tice.2016.11.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 10/06/2016] [Accepted: 11/06/2016] [Indexed: 01/24/2023]
Abstract
The Golgi apparatus is a central organelle of the secretory pathway involved in the post-translational modification and sorting of lipids and proteins. In mammalian cells, the Golgi apparatus is composed of stacks of cisternae organized in polarized manner, which are interconnected by membrane tubules to constitute the Golgi ribbon, located in the proximity of the centrosome. Besides the processing and transport of cargo, the Golgi complex is actively involved in the regulation of mitotic entry, cytoskeleton organization and dynamics, calcium homeostasis, and apoptosis, representing a signalling platform for the control of several cellular functions, including signalling initiated by receptors located at the plasma membrane. Alterations of the conventional Golgi organization are associated to many disorders, such as cancer or different neurodegenerative diseases. In this review, we examine the functional implications of modifications of Golgi structure in neurodegenerative disorders, with a focus on the role of Golgi fragmentation in the development of Alzheimer's disease. The comprehension of the mechanism that induces Golgi fragmentation and of its downstream effects on neuronal function have the potential to contribute to the development of more effective therapies to treat or prevent some of these disorders.
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Affiliation(s)
- Inmaculada Ayala
- Institute of Protein Biochemistry, National Research Council, Via P. Castellino 111, 80131 Naples, Italy.
| | - Antonino Colanzi
- Institute of Protein Biochemistry, National Research Council, Via P. Castellino 111, 80131 Naples, Italy.
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73
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Tisdale EJ, Talati NK, Artalejo CR, Shisheva A. GAPDH binds Akt to facilitate cargo transport in the early secretory pathway. Exp Cell Res 2016; 349:310-319. [PMID: 27818247 DOI: 10.1016/j.yexcr.2016.10.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 10/12/2016] [Accepted: 10/31/2016] [Indexed: 01/12/2023]
Abstract
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) undergoes numerous post-translational modifications, which impart new function and influence intracellular location. For example, atypical PKC ι/λ phosphorylates GAPDH that locates to vesicular tubular clusters and is required for retrograde membrane trafficking in the early secretory pathway. GAPDH is also required in the endocytic pathway; substitution of Pro234 to Ser (Pro234Ser) rendered CHO cells defective in endocytosis. To determine if GAPDH (Pro234Ser) could inhibit endoplasmic reticulum to Golgi trafficking, we introduced the recombinant mutant enzyme into several biochemical and morphological transport assays. The mutant protein efficiently blocked vesicular stomatitis virus-G protein transport. Because GAPDH binds to microtubules (MTs), we evaluated MT binding and MT intracellular distribution in the presence of the mutant. Although these properties were not changed relative to wild-type, GAPDH (Pro234Ser) altered Golgi complex morphology. We determined that the GAPDH point mutation disrupted association between the enzyme and the serine/threonine kinase Akt. Interestingly Rab1, which functions in anterograde-directed trafficking, stimulates GAPDH-Akt association with membranes in a quantitative binding assay. In contrast, Rab2 does not stimulate GAPDH-Akt membrane binding but instead recruits GAPDH-aPKC. We propose a mechanism whereby the association of GAPDH with Akt or with aPKC serves as a switch to discriminate between anterograde directed cargo and recycling cargo retrieved back to the ER, respectively.
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Affiliation(s)
- Ellen J Tisdale
- Department of Pharmacology, Wayne State University School of Medicine, 540 E. Canfield Ave., 6374 Scott Hall, Detroit, MI 48201, USA.
| | - Nikunj K Talati
- Department of Pharmacology, Wayne State University School of Medicine, 540 E. Canfield Ave., 6374 Scott Hall, Detroit, MI 48201, USA
| | - Cristina R Artalejo
- Department of Pharmacology, Wayne State University School of Medicine, 540 E. Canfield Ave., 6374 Scott Hall, Detroit, MI 48201, USA
| | - Assia Shisheva
- Department of Physiology, Wayne State University School of Medicine, 540 E. Canfield Ave., 6374 Scott Hall, Detroit, MI 48201, USA
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74
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Rho GTPases operating at the Golgi complex: Implications for membrane traffic and cancer biology. Tissue Cell 2016; 49:163-169. [PMID: 27720426 DOI: 10.1016/j.tice.2016.09.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 09/09/2016] [Accepted: 09/26/2016] [Indexed: 11/20/2022]
Abstract
The Golgi complex is the central unit of the secretory pathway, modifying, processing and sorting proteins and lipids to their correct cellular localisation. Changes to proteins at the Golgi complex can have deleterious effects on the function of this organelle, impeding trafficking routes through it, potentially resulting in disease. It is emerging that several Rho GTPase proteins, namely Cdc42, RhoBTB3, RhoA and RhoD are at least in part localised to the Golgi complex, and a number of studies have shown that dysregulation of their levels or activity can be associated with cellular changes which ultimately drive cancer progression. In this mini-review we highlight some of the recent work that explores links between form and function of the Golgi complex, Rho GTPases and cancer.
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75
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Shete A, Suryawanshi P, Godbole S, Pawar J, Paranjape R, Thakar M. HIV-infected CD4+ T Cells Use T-bet-dependent Pathway for Production of IL-10 Upon Antigen Recognition. Scand J Immunol 2016; 83:288-96. [PMID: 27028319 DOI: 10.1111/sji.12422] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 02/15/2016] [Indexed: 01/11/2023]
Abstract
Interleukin (IL)-10 has been implicated in persistence of pathogens in a number of chronic infections. Infected CD4+ cells upon reactivation with HIV antigens were also shown to produce IL-10, which might contribute to their persistence. Hence, it is crucial to determine mechanisms regulating IL-10 production after activation with HIV antigens for devising effective blocking strategies. In this study, ERK-, T-bet- and FoxP3-dependent pathways were evaluated for their possible roles in IL-10 production by infected CD4+ cells after reactivation with HIV Env. Intracellular and secreted IL-10 levels were determined by flow cytometry and Bioplex assay after treating PBMCs with PD98059, tipifarnib and cyclosporin A for blocking of ERK-, T-bet-and FoxP3-dependent pathways, respectively. Baseline levels of T-bet, pERK were higher in P24+ CD4+ cells as compared to uninfected CD4+ cells, which increased further after activation with Env. Inhibition of T-bet resulted in 2.3-fold reduction of IL-10 expression whereas ERK and FoxP3 inhibition failed to cause suppression of IL-10 expression. Conversely, IL-10 secreted by PBMCs was inhibited maximally after ERK inhibition suggesting its role in regulation of cytokine secretory pathway. IFN-γ was found to be suppressed after treatment with inhibitors of all these pathways. Thus, the study highlighted need for IL-10 blockade along with the use of antigens for therapeutic vaccinations or latency reversal and identified the T-bet-dependent pathway as an important pathway regulating IL-10 production by infected CD4+ cells. However, simultaneous blockade of IFN-γ precludes use of inhibitor of this pathway as an IL-10 blocking strategy.
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Affiliation(s)
- A Shete
- National AIDS Research Institute, Pune, India
| | | | - S Godbole
- National AIDS Research Institute, Pune, India
| | - J Pawar
- National AIDS Research Institute, Pune, India
| | - R Paranjape
- National AIDS Research Institute, Pune, India
| | - M Thakar
- National AIDS Research Institute, Pune, India
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76
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Hu H, Gourguechon S, Wang CC, Li Z. The G1 Cyclin-dependent Kinase CRK1 in Trypanosoma brucei Regulates Anterograde Protein Transport by Phosphorylating the COPII Subunit Sec31. J Biol Chem 2016; 291:15527-39. [PMID: 27252375 PMCID: PMC4957039 DOI: 10.1074/jbc.m116.715185] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Indexed: 01/02/2023] Open
Abstract
Transport of secretory proteins from the endoplasmic reticulum to the Golgi is mediated by the coat protein II (COPII) complex comprising a Sec23-Sec24 heterodimer and a Sec13-Sec31 heterotetramer. The mechanisms underlying COPII-mediated protein trafficking have been well defined, but the extent of regulation of this secretory machinery by cellular signaling pathways remains poorly understood. Here, we report that CRK1, a G1 cyclin-dependent kinase in Trypanosoma brucei, regulates anterograde protein trafficking by phosphorylating Sec31. Depletion of CRK1 abolished anterograde transport of the secretory protein and disrupted the localization of multiple Golgi proteins, reminiscent of Sec31 depletion. CRK1 phosphorylates Sec31 at multiple serine/threonine sites, and mutation of these phosphosites to alanine recapitulates the protein trafficking defects caused by Sec31 depletion. Mutation of these CRK1 phosphosites to aspartate restored Sec31 function. Taken together, these results uncover a novel function of CRK1 in anterograde protein trafficking and elucidate the mechanistic role of CRK1 in protein trafficking through regulation of the COPII subunit Sec31.
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Affiliation(s)
- Huiqing Hu
- From the Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas 77030 and
| | - Stéphane Gourguechon
- the Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, California 94158
| | - Ching C Wang
- the Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, California 94158
| | - Ziyin Li
- From the Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas 77030 and
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77
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Friday SC, Fox DA. Phospholipase D enzymes facilitate IL-17- and TNFα-induced expression of proinflammatory genes in rheumatoid arthritis synovial fibroblasts (RASF). Immunol Lett 2016; 174:9-18. [DOI: 10.1016/j.imlet.2016.04.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 04/01/2016] [Accepted: 04/01/2016] [Indexed: 11/30/2022]
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78
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Doly S, Shirvani H, Gäta G, Meye F, Emerit MB, Enslen H, Achour L, Pardo-Lopez L, Kwon YS, Armand V, Gardette R, Giros B, Gassmann M, Bettler B, Mameli M, Darmon M, Marullo S. GABAB receptor cell-surface export is controlled by an endoplasmic reticulum gatekeeper. Mol Psychiatry 2016; 21:480-90. [PMID: 26033241 PMCID: PMC4828513 DOI: 10.1038/mp.2015.72] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 04/24/2015] [Accepted: 04/28/2015] [Indexed: 12/20/2022]
Abstract
Endoplasmic reticulum (ER) release and cell-surface export of many G protein-coupled receptors (GPCRs) are tightly regulated. For gamma-aminobutyric acid (GABA)B receptors of GABA, the major mammalian inhibitory neurotransmitter, the ligand-binding GB1 subunit is maintained in the ER by unknown mechanisms in the absence of hetero-dimerization with the GB2 subunit. We report that GB1 retention is regulated by a specific gatekeeper, PRAF2. This ER resident transmembrane protein binds to GB1, preventing its progression in the biosynthetic pathway. GB1 release occurs upon competitive displacement from PRAF2 by GB2. PRAF2 concentration, relative to that of GB1 and GB2, tightly controls cell-surface receptor density and controls GABAB function in neurons. Experimental perturbation of PRAF2 levels in vivo caused marked hyperactivity disorders in mice. These data reveal an unanticipated major impact of specific ER gatekeepers on GPCR function and identify PRAF2 as a new molecular target with therapeutic potential for psychiatric and neurological diseases involving GABAB function.
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Affiliation(s)
- Stéphane Doly
- Institut Cochin
INSERMCentre National de la Recherche ScientifiqueUniversité Paris Descartes - Paris 5Institut National de la Recherche Agronomique (INRA)Université de Versailles Saint-Quentin-en-Yvelines22 Rue Méchain, 75014 Paris
| | - Hamasseh Shirvani
- Institut Cochin
INSERMCentre National de la Recherche ScientifiqueUniversité Paris Descartes - Paris 5Institut National de la Recherche Agronomique (INRA)Université de Versailles Saint-Quentin-en-Yvelines22 Rue Méchain, 75014 Paris
| | - Gabriel Gäta
- Institut Cochin
INSERMCentre National de la Recherche ScientifiqueUniversité Paris Descartes - Paris 5Institut National de la Recherche Agronomique (INRA)Université de Versailles Saint-Quentin-en-Yvelines22 Rue Méchain, 75014 Paris
| | - Frank Meye
- Institut du Fer à Moulin
Université Pierre et Marie Curie - Paris 6INSERM17 Rue du fer à moulin 75005 Paris
| | - Michel-Boris Emerit
- CPN, Centre de Psychiatrie et Neurosciences
INSERMUniversité Paris Descartes - Paris 5Groupe Hospitalier BrocaSite Broca - Sainte Anne 2 ter Rue d'Alésia75014 Paris
| | - Hervé Enslen
- Institut Cochin
INSERMCentre National de la Recherche ScientifiqueUniversité Paris Descartes - Paris 5Institut National de la Recherche Agronomique (INRA)Université de Versailles Saint-Quentin-en-Yvelines22 Rue Méchain, 75014 Paris
| | - Lamia Achour
- Institut Cochin
INSERMCentre National de la Recherche ScientifiqueUniversité Paris Descartes - Paris 5Institut National de la Recherche Agronomique (INRA)Université de Versailles Saint-Quentin-en-Yvelines22 Rue Méchain, 75014 Paris
| | - Liliana Pardo-Lopez
- Institut Cochin
INSERMCentre National de la Recherche ScientifiqueUniversité Paris Descartes - Paris 5Institut National de la Recherche Agronomique (INRA)Université de Versailles Saint-Quentin-en-Yvelines22 Rue Méchain, 75014 Paris
| | - Yang Seung Kwon
- CPN, Centre de Psychiatrie et Neurosciences
INSERMUniversité Paris Descartes - Paris 5Groupe Hospitalier BrocaSite Broca - Sainte Anne 2 ter Rue d'Alésia75014 Paris
| | - Vincent Armand
- CPN, Centre de Psychiatrie et Neurosciences
INSERMUniversité Paris Descartes - Paris 5Groupe Hospitalier BrocaSite Broca - Sainte Anne 2 ter Rue d'Alésia75014 Paris
| | - Robert Gardette
- CPN, Centre de Psychiatrie et Neurosciences
INSERMUniversité Paris Descartes - Paris 5Groupe Hospitalier BrocaSite Broca - Sainte Anne 2 ter Rue d'Alésia75014 Paris
| | - Bruno Giros
- Physiopathologie des Maladies du Système Nerveux Central
Université Pierre et Marie Curie - Paris 6INSERMCentre National de la Recherche ScientifiqueBâtiment B, 4ème étage, case courrier 37 9 Quai Saint Bernard 75252 Paris Cedex 05
- Service Psychiatrie
McGill University [Montréal]Institut Universitaire en Santé Mentale Douglas6875 Boulevard Lasalle, Montréal, QC H4H 1R2
| | - Martin Gassmann
- Department of Biomedicine
University of Basel Petersplatz 1, 4003 Basel
| | - Bernhard Bettler
- Department of Biomedicine
University of Basel Petersplatz 1, 4003 Basel
| | - Manuel Mameli
- Institut du Fer à Moulin
Université Pierre et Marie Curie - Paris 6INSERM17 Rue du fer à moulin 75005 Paris
| | - Michèle Darmon
- Institut Cochin
INSERMCentre National de la Recherche ScientifiqueUniversité Paris Descartes - Paris 5Institut National de la Recherche Agronomique (INRA)Université de Versailles Saint-Quentin-en-Yvelines22 Rue Méchain, 75014 Paris
| | - Stefano Marullo
- Institut Cochin
INSERMCentre National de la Recherche ScientifiqueUniversité Paris Descartes - Paris 5Institut National de la Recherche Agronomique (INRA)Université de Versailles Saint-Quentin-en-Yvelines22 Rue Méchain, 75014 Paris
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79
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Luini A, Parashuraman S. Signaling at the Golgi: sensing and controlling the membrane fluxes. Curr Opin Cell Biol 2016; 39:37-42. [PMID: 26908115 DOI: 10.1016/j.ceb.2016.01.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 01/28/2016] [Accepted: 01/30/2016] [Indexed: 11/16/2022]
Abstract
Over the past few decades, it has emerged that the Golgi (and other secretory stations) is host to a variety of signaling molecules and can act as a signaling hub that receives, emits and elaborates signals. This endomembrane-based signaling apparatus appears to have more than one purpose. Its most fundamental function appears to be the auto-regulation of the biosynthetic apparatus to maintain and/or optimize its own activities and to coordinate such activities with those of other cellular modules.(1) This is achieved by dedicated control devices that provide stability, robustness, precision, sensitivity and complexity to cellular behaviors.
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Affiliation(s)
- Alberto Luini
- Institute of Protein Biochemistry, National Research Council, Via P. Castellino 111, 80131 Naples, Italy; Istituto di Ricovero e Cura a Carattere Scientifico SDN, Via Emanuele Gianturco, 113, 80143 Naples, Italy.
| | - Seetharaman Parashuraman
- Institute of Protein Biochemistry, National Research Council, Via P. Castellino 111, 80131 Naples, Italy
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80
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Baschieri F, Uetz-von Allmen E, Legler DF, Farhan H. Loss of GM130 in breast cancer cells and its effects on cell migration, invasion and polarity. Cell Cycle 2016; 14:1139-47. [PMID: 25892554 DOI: 10.1080/15384101.2015.1007771] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Spatially distinct pools of the small GTPase Cdc42 were observed, but the major focus of research so far has been to investigate its signaling at the plasma membrane. We recently showed that the Golgi pool of Cdc42 is relevant for cell polarity and that it is regulated by GM130, a Golgi matrix protein. Loss of GM130 abrogated cell polarity and consistent with the notion that polarity is frequently impaired in cancer, we found that GM130 is downregulated in colorectal cancer. Whether the loss of GM130 solely affects polarity, or whether it affects other processes relevant for tumorigenesis remains unclear. In a panel of breast cancer cells lines, we investigated the consequences of GM130 depletion on traits of relevance for tumor progression, such as survival, proliferation, adhesion, migration and invasion. We show that cellular assays that depend on polarity, such as chemotaxis and wound scratch assays, are only of limited use to investigate the role of polarity modulators in cancer. Depletion of GM130 increases cellular velocity and increases the invasiveness of breast cancer cells, therefore supporting the view that alterations of polarity contribute to tumor progression.
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Affiliation(s)
- Francesco Baschieri
- a Biotechnology Institute Thurgau; University of Konstanz ; Kreuzlingen , Switzerland
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81
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Cdc42 and Cellular Polarity: Emerging Roles at the Golgi. Trends Cell Biol 2015; 26:241-248. [PMID: 26704441 DOI: 10.1016/j.tcb.2015.11.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 11/09/2015] [Accepted: 11/13/2015] [Indexed: 01/10/2023]
Abstract
Cdc42 belongs to the Rho family of small GTPases and plays key roles in cellular events of polarity. This role of Cdc42 has typically been attributed to its function at the plasma membrane. However, Cdc42 also exists at the Golgi complex. Here we summarize major insights that have been gathered in studying the Golgi pool of Cdc42 and propose that Golgi-localized Cdc42 enables the cell to diversify the function of Cdc42, which in some cases represents new roles and in other cases acts to complement the established roles of Cdc42 at the plasma membrane. Studies on how Cdc42 acts at the Golgi also suggest key questions to address in the future.
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82
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Alvarez-Miranda EA, Sinnl M, Farhan H. Alteration of Golgi Structure by Stress: A Link to Neurodegeneration? Front Neurosci 2015; 9:435. [PMID: 26617486 PMCID: PMC4641911 DOI: 10.3389/fnins.2015.00435] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 10/29/2015] [Indexed: 12/14/2022] Open
Abstract
The Golgi apparatus is well-known for its role as a sorting station in the secretory pathway as well as for its role in regulating post-translational protein modification. Another role for the Golgi is the regulation of cellular signaling by spatially regulating kinases, phosphatases, and GTPases. All these roles make it clear that the Golgi is a central regulator of cellular homeostasis. The response to stress and the initiation of adaptive responses to cope with it are fundamental abilities of all living cells. It was shown previously that the Golgi undergoes structural rearrangements under various stress conditions such as oxidative or osmotic stress. Neurodegenerative diseases are also frequently associated with alterations of Golgi morphology and many stress factors have been described to play an etiopathological role in neurodegeneration. It is however unclear whether the stress-Golgi connection plays a role in neurodegenerative diseases. Using a combination of bioinformatics modeling and literature mining, we will investigate evidence for such a tripartite link and we ask whether stress-induced Golgi arrangements are cause or consequence in neurodegeneration.
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Affiliation(s)
| | - Markus Sinnl
- Department of Statistics and Operations Research, University of Vienna Vienna, Austria
| | - Hesso Farhan
- Biotechnology Institute Thurgau Kreuzlingen, Switzerland ; Department of Biology, University of Konstanz Konstanz, Germany
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83
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Lee WY, Goh G, Chia J, Boey A, Gunko NV, Bard F. The Ubiquitin Ligase CBLC Maintains the Network Organization of the Golgi Apparatus. PLoS One 2015; 10:e0138789. [PMID: 26393512 PMCID: PMC4579092 DOI: 10.1371/journal.pone.0138789] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 09/03/2015] [Indexed: 11/21/2022] Open
Abstract
The Golgi apparatus plays a pivotal role in the sorting and post-translational modifications of secreted and membrane proteins. In mammalian cells, the Golgi is organized in stacks of cisternae linked together to form a network with a ribbon shape. Regulation of Golgi ribbon formation is poorly understood. Here we find in an image-based RNAi screen that depletion of the ubiquitin-ligase CBLC induces Golgi fragmentation. Depletions of the close homologues CBL and CBLB do not induce any visible defects. In CBLC-depleted cells, Golgi stacks appear relatively unperturbed at both the light and electron microscopy levels, suggesting that CBLC controls mostly network organization. CBLC partially localizes on Golgi membranes and this localization is enhanced after activation of the SRC kinase. Inhibition of SRC reverts CBLC depletion effects, suggesting interplay between the two. CBLC's regulation of Golgi network requires its ubiquitin ligase activity. However, SRC levels are not significantly affected by CBLC, and CBLC knockdown does not phenocopy SRC activation, suggesting that CBLC's action at the Golgi is not direct downregulation of SRC. Altogether, our results demonstrate a role of CBLC in regulating Golgi ribbon by antagonizing the SRC tyrosine kinase.
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Affiliation(s)
- Wan Yin Lee
- Institute of Molecular and Cell Biology, Singapore, Singapore
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Germaine Goh
- Institute of Molecular and Cell Biology, Singapore, Singapore
| | - Joanne Chia
- Institute of Molecular and Cell Biology, Singapore, Singapore
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Adrian Boey
- Institute of Molecular and Cell Biology, Singapore, Singapore
- Institute of Medical Biology, Singapore, Singapore
- IMB-IMCB Joint Electron Microscopy Suite, Singapore, Singapore
| | - Natalia V. Gunko
- Institute of Molecular and Cell Biology, Singapore, Singapore
- Institute of Medical Biology, Singapore, Singapore
- IMB-IMCB Joint Electron Microscopy Suite, Singapore, Singapore
| | - Frederic Bard
- Institute of Molecular and Cell Biology, Singapore, Singapore
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
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84
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Stothert AR, Fontaine SN, Sabbagh JJ, Dickey CA. Targeting the ER-autophagy system in the trabecular meshwork to treat glaucoma. Exp Eye Res 2015; 144:38-45. [PMID: 26302411 DOI: 10.1016/j.exer.2015.08.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 07/23/2015] [Accepted: 08/18/2015] [Indexed: 12/19/2022]
Abstract
A major drainage network involved in aqueous humor dynamics is the conventional outflow pathway, which is gated by the trabecular meshwork (TM). The TM acts as a molecular sieve, providing resistance to aqueous outflow, which is responsible for regulating intraocular pressure (IOP). If the TM is damaged, aqueous outflow is impaired, IOP increases and glaucoma can manifest. Mutations in the MYOC gene cause hereditary primary open-angle glaucoma (POAG) by promoting the abnormal amyloidosis of the myocilin protein in the endoplasmic reticulum (ER), leading to ER stress-induced TM cell death. Myocilin accumulation is observed in approximately 70-80% of all glaucoma cases suggesting that environmental or other genetic factors may also promote myocilin toxicity. For example, simply preventing myocilin glycosylation is sufficient to promote its abnormal accretion. These myocilin amyloids are unique as there are no other known pathogenic proteins that accumulate within the ER of TM cells and cause toxicity. Moreover, this pathogenic accumulation only kills TM cells, despite expression of this protein in other cell types, suggesting that another modifier exclusive to the TM participates in the proteotoxicity of myocilin. ER autophagy (reticulophagy) is one of the pathways essential for myocilin clearance that can be impacted dramatically by aging and other environmental factors such as nutrition. This review will discuss the link between myocilin and autophagy, evaluating the role of this degradation pathway in glaucoma as well as its potential as a therapeutic target.
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Affiliation(s)
- Andrew R Stothert
- Department of Molecular Medicine, Byrd Alzheimer's Research Institute, University of South Florida, Tampa, FL 33613, USA
| | - Sarah N Fontaine
- Department of Molecular Medicine, Byrd Alzheimer's Research Institute, University of South Florida, Tampa, FL 33613, USA
| | - Jonathan J Sabbagh
- Department of Molecular Medicine, Byrd Alzheimer's Research Institute, University of South Florida, Tampa, FL 33613, USA
| | - Chad A Dickey
- Department of Molecular Medicine, Byrd Alzheimer's Research Institute, University of South Florida, Tampa, FL 33613, USA.
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85
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Wu B, Wang J, Zhao Y, Guo W. Biochemical analysis of Rabin8, the guanine nucleotide exchange factor for Rab8. Methods Cell Biol 2015; 130:59-68. [PMID: 26360028 DOI: 10.1016/bs.mcb.2015.06.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The Rab GTPases are master regulators of endosomal trafficking in eukaryotic cells. Among them, Rab8 plays an important role in tubulovesicular trafficking from the trans-Golgi network and recycling endosomes to the plasma membrane. Rab8 is activated by its guanine nucleotide exchange factor, Rabin8. In order to understand the molecular mechanisms that control endosomal recycling to the plasma membrane, it is pivotal to understand how Rabin8 is regulated in cells. Recently, biochemical and cell biological studies have identified several mechanisms for Rabin8 activation, which involves the relief of the intramolecular autoinhibition of Rabin8. Here we describe biochemical methods that we have used recently to study the activation of Rabin8.
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Affiliation(s)
- Bin Wu
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Juanfei Wang
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Yuting Zhao
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Wei Guo
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
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86
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Farhan H. Systems biology of the secretory pathway: what have we learned so far? Biol Cell 2015; 107:205-17. [PMID: 25756903 DOI: 10.1111/boc.201400065] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 03/04/2015] [Indexed: 12/26/2022]
Abstract
Several RNAi screens were performed in search for regulators of the secretory pathway. These screens were performed in different organisms and cell lines and relied on different readouts. Therefore, they have only little overlap among their hits, leading to the question of what we have learned from this approach so far and how these screens contributed towards an integrative understanding of the endomembrane system. The aim of this review is to revisit these screens and discuss their strengths and weaknesses as well as potential reasons for their failure to overlap with each other. As with secretory trafficking, RNAi screens were also performed on other cellular processes such as cell migration and autophagy, both of which were shown to be intimately linked to secretion. Another aim of this review is to compare the outcome of the RNAi screens on secretion, autophagy and cell migration and ask whether the functional genomic approaches have uncovered potential mechanistic insights into the links between these processes.
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Affiliation(s)
- Hesso Farhan
- Department of Biology, University of Konstanz, Konstanz, Germany.,Biotechnology Institute Thurgau, Kreuzlingen, Switzerland
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87
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Münzberg C, Höhn K, Krndija D, Maaß U, Bartsch DK, Slater EP, Oswald F, Walther P, Seufferlein T, von Wichert G. IGF-1 drives chromogranin A secretion via activation of Arf1 in human neuroendocrine tumour cells. J Cell Mol Med 2015; 19:948-59. [PMID: 25754106 PMCID: PMC4420598 DOI: 10.1111/jcmm.12473] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 09/15/2014] [Indexed: 01/18/2023] Open
Abstract
Hypersecretion is the major symptom of functional neuroendocrine tumours. The mechanisms that contribute to this excessive secretion of hormones are still elusive. A key event in secretion is the exit of secretory products from the Golgi apparatus. ADP-ribosylation factor (Arf) GTPases are known to control vesicle budding and trafficking, and have a leading function in the regulation of formation of secretory granula at the Golgi. Here, we show that Arf1 is the predominant Arf protein family member expressed in the neuroendocrine pancreatic tumour cell lines BON and QGP-1. In BON cells Arf1 colocalizes with Golgi markers as well as chromogranin A, and shows significant basal activity. The inhibition of Arf1 activity or expression significantly impaired secretion of chromogranin A. Furthermore, we show that the insulin-like growth factor 1 (IGF-1), a major regulator of growth and secretion in BON cells, induces Arf1 activity. We found that activation of Arf1 upon IGF-1 receptor stimulation is mediated by MEK/ERK signalling pathway in BON and QGP-1 cells. Moreover, the activity of Arf1 in BON cells is mediated by autocrinely secreted IGF-1, and concomitantly, autocrine IGF1 secretion is maintained by Arf1 activity. In summary, our data indicate an important regulatory role for Arf1 at the Golgi in hypersecretion in neuroendocrine cancer cells.
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88
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Activation of Rab8 guanine nucleotide exchange factor Rabin8 by ERK1/2 in response to EGF signaling. Proc Natl Acad Sci U S A 2014; 112:148-53. [PMID: 25535387 DOI: 10.1073/pnas.1412089112] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Exocytosis is tightly regulated in many cellular processes, from neurite expansion to tumor proliferation. Rab8, a member of the Rab family of small GTPases, plays an important role in membrane trafficking from the trans-Golgi network and recycling endosomes to the plasma membrane. Rabin8 is a guanine nucleotide exchange factor (GEF) and major activator of Rab8. Investigating how Rabin8 is activated in cells is thus pivotal to the understanding of the regulation of exocytosis. Here we show that phosphorylation serves as an important mechanism for Rabin8 activation. We identified Rabin8 as a direct phospho-substrate of ERK1/2 in response to EGF signaling. At the molecular level, ERK phosphorylation relieves the autoinhibition of Rabin8, thus promoting its GEF activity. We further demonstrate that blocking ERK1/2-mediated phosphorylation of Rabin8 inhibits transferrin recycling to the plasma membrane. Together, our results suggest that ERK1/2 activate Rabin8 to regulate vesicular trafficking to the plasma membrane in response to extracellular signaling.
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89
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Kannan R, Kuzina I, Wincovitch S, Nowotarski SH, Giniger E. The Abl/enabled signaling pathway regulates Golgi architecture in Drosophila photoreceptor neurons. Mol Biol Cell 2014; 25:2993-3005. [PMID: 25103244 PMCID: PMC4230588 DOI: 10.1091/mbc.e14-02-0729] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 06/04/2014] [Accepted: 07/29/2014] [Indexed: 11/24/2022] Open
Abstract
The Golgi apparatus is optimized separately in different tissues for efficient protein trafficking, but we know little of how cell signaling shapes this organelle. We now find that the Abl tyrosine kinase signaling pathway controls the architecture of the Golgi complex in Drosophila photoreceptor (PR) neurons. The Abl effector, Enabled (Ena), selectively labels the cis-Golgi in developing PRs. Overexpression or loss of function of Ena increases the number of cis- and trans-Golgi cisternae per cell, and Ena overexpression also redistributes Golgi to the most basal portion of the cell soma. Loss of Abl or its upstream regulator, the adaptor protein Disabled, lead to the same alterations of Golgi as does overexpression of Ena. The increase in Golgi number in Abl mutants arises in part from increased frequency of Golgi fission events and a decrease in fusions, as revealed by live imaging. Finally, we demonstrate that the effects of Abl signaling on Golgi are mediated via regulation of the actin cytoskeleton. Together, these data reveal a direct link between cell signaling and Golgi architecture. Moreover, they raise the possibility that some of the effects of Abl signaling may arise, in part, from alterations of protein trafficking and secretion.
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Affiliation(s)
- Ramakrishnan Kannan
- Axon Guidance and Neural Connectivity Unit, Basic Neuroscience Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Irina Kuzina
- Axon Guidance and Neural Connectivity Unit, Basic Neuroscience Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Stephen Wincovitch
- Cytogenetics and Microscopy Core, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892
| | - Stephanie H Nowotarski
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Edward Giniger
- Axon Guidance and Neural Connectivity Unit, Basic Neuroscience Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
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90
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Baschieri F, Confalonieri S, Bertalot G, Di Fiore PP, Dietmaier W, Leist M, Crespo P, Macara IG, Farhan H. Spatial control of Cdc42 signalling by a GM130-RasGRF complex regulates polarity and tumorigenesis. Nat Commun 2014; 5:4839. [PMID: 25208761 DOI: 10.1038/ncomms5839] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 07/29/2014] [Indexed: 12/27/2022] Open
Abstract
The small GTPase Cdc42 is a key regulator of polarity, but little is known in mammals about its spatial regulation and the relevance of spatial Cdc42 pools for polarity. Here we report the identification of a GM130-RasGRF complex as a regulator of Cdc42 at the Golgi. Silencing GM130 results in RasGRF-dependent inhibition of the Golgi pool of Cdc42, but does not affect Cdc42 at the cell surface. Furthermore, active Cdc42 at the Golgi is important to sustain asymmetric front-rear Cdc42-GTP distribution in directionally migrating cells. Concurrent to Cdc42 inhibition, silencing GM130 also results in RasGRF-dependent Ras-ERK pathway activation. Moreover, depletion of GM130 is sufficient to induce E-cadherin downregulation, indicative of a loss in cell polarity and epithelial identity. Accordingly, GM130 expression is frequently lost in colorectal and breast cancer patients. These findings establish a previously unrecognized role for a GM130-RasGRF-Cdc42 connection in regulating polarity and tumorigenesis.
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Affiliation(s)
- Francesco Baschieri
- 1] University of Konstanz, 78464 Konstanz, Germany [2] Biotechnology Institute Thurgau, University of Konstanz, Kreuzlingen CH-8280, Switzerland
| | - Stefano Confalonieri
- 1] Molecular Medicine for Care Program, European Institute of Oncology, Via Ripamonti 435, 20141 Milan, Italy [2] IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy
| | - Giovanni Bertalot
- Molecular Medicine for Care Program, European Institute of Oncology, Via Ripamonti 435, 20141 Milan, Italy
| | - Pier Paolo Di Fiore
- 1] Molecular Medicine for Care Program, European Institute of Oncology, Via Ripamonti 435, 20141 Milan, Italy [2] IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy [3] Dipartimento di Scienze della Salute, Università degli Studi di Milano, Via Antonio di Rudinì 8, 20142 Milan, Italy
| | - Wolfgang Dietmaier
- University of Regensburg, Institute of Pathology and molecular diagnostics, 93053 Regensbur, Germany
| | | | - Piero Crespo
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Cantabria-SODERCAN. 39005 Santander, Spain
| | - Ian G Macara
- Department of Cell &Developmental Biology, Vanderbilt University, Nashville, Tennessee 37235, USA
| | - Hesso Farhan
- 1] University of Konstanz, 78464 Konstanz, Germany [2] Biotechnology Institute Thurgau, University of Konstanz, Kreuzlingen CH-8280, Switzerland
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91
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Kajiwara K, Ikeda A, Aguilera-Romero A, Castillon GA, Kagiwada S, Hanada K, Riezman H, Muñiz M, Funato K. Osh proteins regulate COPII-mediated vesicular transport of ceramide from the endoplasmic reticulum in budding yeast. J Cell Sci 2013; 127:376-87. [PMID: 24213531 DOI: 10.1242/jcs.132001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Lipids synthesized at the endoplasmic reticulum (ER) are delivered to the Golgi by vesicular and non-vesicular pathways. ER-to-Golgi transport is crucial for maintaining the different membrane lipid composition and identities of organelles. Despite their importance, mechanisms regulating transport remain elusive. Here we report that in yeast coat protein complex II (COPII) vesicle-mediated transport of ceramide from the ER to the Golgi requires oxysterol-binding protein homologs, Osh proteins, which have been implicated in lipid homeostasis. Because Osh proteins are not required to transport proteins to the Golgi, these results indicate a specific requirement for the Osh proteins in the transport of ceramide. In addition, we provide evidence that Osh proteins play a negative role in COPII vesicle biogenesis. Together, our data suggest that ceramide transport and sphingolipid levels between the ER and Golgi are maintained by two distinct functions of Osh proteins, which negatively regulate COPII vesicle formation and positively control a later stage, presumably fusion of ceramide-enriched vesicles with Golgi compartments.
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Affiliation(s)
- Kentaro Kajiwara
- Department of Biofunctional Science and Technology, Graduate School of Biosphere Science, Hiroshima University, Hiroshima 739-8528, Japan
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92
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Tillmann KD, Millarte V, Farhan H. Regulation of traffic and organelle architecture of the ER-Golgi interface by signal transduction. Histochem Cell Biol 2013; 140:297-306. [PMID: 23821161 DOI: 10.1007/s00418-013-1118-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/22/2013] [Indexed: 01/10/2023]
Abstract
The components that control trafficking between organelles of the secretory pathway as well as their architecture were uncovered to a reasonable extent in the past decades. However, only recently did we begin to explore the regulation of the secretory pathway by cellular signaling. In the current review, we focus on trafficking between the endoplasmic reticulum and the Golgi apparatus. We highlight recent advances that have been made toward a better understanding of how the secretory pathway is regulated by signaling and discuss how this knowledge is important to obtain an integrative view of secretion in the context of other homeostatic processes such as growth and proliferation.
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Affiliation(s)
- Kerstin D Tillmann
- Biotechnology Institute Thurgau, Unterseestrasse 47, 8280, Kreuzlingen, Switzerland
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93
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RNAi screening reveals a large signaling network controlling the Golgi apparatus in human cells. Mol Syst Biol 2013; 8:629. [PMID: 23212246 PMCID: PMC3542528 DOI: 10.1038/msb.2012.59] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 10/11/2012] [Indexed: 12/11/2022] Open
Abstract
RNAi screening and automated image analysis reveal 180 kinases and phosphatases regulating the organization of the Golgi apparatus. Most of these genes also control the expression of specific glycans, pointing to a web of interactions between signaling cascades and glycosylation at the Golgi. ![]()
Golgi organization was probed with three markers of different Golgi compartments and quantitative morphological analysis. Knockdowns of ∼20% of all known kinases and phosphatases affected the Golgi globally or in a compartment-specific manner, and were comparable in degree to the depletion of known membrane traffic regulators such as SNAREs. Several cell surface receptors, their cognate ligands and downstream effectors regulate Golgi organization, suggesting a large regulatory network. Most signaling genes affected both Golgi morphology and the expression of specific glycans.
The Golgi apparatus has many important physiological functions, including sorting of secretory cargo and biosynthesis of complex glycans. These functions depend on the intricate and compartmentalized organization of the Golgi apparatus. To investigate the mechanisms that regulate Golgi architecture, we developed a quantitative morphological assay using three different Golgi compartment markers and quantitative image analysis, and performed a kinome- and phosphatome-wide RNAi screen in HeLa cells. Depletion of 159 signaling genes, nearly 20% of genes assayed, induced strong and varied perturbations in Golgi morphology. Using bioinformatics data, a large regulatory network could be constructed. Specific subnetworks are involved in phosphoinositides regulation, acto-myosin dynamics and mitogen activated protein kinase signaling. Most gene depletion also affected Golgi functions, in particular glycan biosynthesis, suggesting that signaling cascades can control glycosylation directly at the Golgi level. Our results provide a genetic overview of the signaling pathways that control the Golgi apparatus in human cells.
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94
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Abstract
Small GTPases regulate a wide range of homeostatic processes such as cytoskeletal dynamics, organelle homeostasis, cell migration and vesicle trafficking, as well as in pathologic conditions such as carcinogenesis and metastatic spreading. Therefore, it is important to understand the regulation of small GTPase signaling, but this is complicated by the fact that crosstalk exists between different GTPase families and that we have to understand how they signal in time and space. The Golgi apparatus represents a hub for several signaling molecules and its importance in this field is constantly increasing. In this review we will discuss small GTPases signaling at the Golgi apparatus. Then, we will highlight recent work that contributed to a better understanding of crosstalk between different small GTPase families, with a special emphasis on their crosstalk at the Golgi apparatus. Finally, we will give a brief overview of available methods and tools to investigate spatio-temporal small GTPase crosstalk.
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Affiliation(s)
- Francesco Baschieri
- Department of Biology, University of Konstanz, Universitätsstrasse 10, D-78457 Konstanz, Germany
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95
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Romero N, Dumur CI, Martinez H, García IA, Monetta P, Slavin I, Sampieri L, Koritschoner N, Mironov AA, De Matteis MA, Alvarez C. Rab1b overexpression modifies Golgi size and gene expression in HeLa cells and modulates the thyrotrophin response in thyroid cells in culture. Mol Biol Cell 2013; 24:617-32. [PMID: 23325787 PMCID: PMC3583665 DOI: 10.1091/mbc.e12-07-0530] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
An increase in Rab1b levels induces changes in Golgi size and in gene expression. These Rab1b-dependent changes require the activity of p38 mitogen-activated protein kinase and the cAMP-responsive element binding protein consensus binding. The results show a Rab1b increase in secretory cells after stimulation and suggest that this increase is required to elicit a secretory response. Rab1b belongs to the Rab-GTPase family that regulates membrane trafficking and signal transduction systems able to control diverse cellular activities, including gene expression. Rab1b is essential for endoplasmic reticulum–Golgi transport. Although it is ubiquitously expressed, its mRNA levels vary among different tissues. This work aims to characterize the role of the high Rab1b levels detected in some secretory tissues. We report that, in HeLa cells, an increase in Rab1b levels induces changes in Golgi size and gene expression. Significantly, analyses applied to selected genes, KDELR3, GM130 (involved in membrane transport), and the proto-oncogene JUN, indicate that the Rab1b increase acts as a molecular switch to control the expression of these genes at the transcriptional level, resulting in changes at the protein level. These Rab1b-dependent changes require the activity of p38 mitogen-activated protein kinase and the cAMP-responsive element-binding protein consensus binding site in those target promoter regions. Moreover, our results reveal that, in a secretory thyroid cell line (FRTL5), Rab1b expression increases in response to thyroid-stimulating hormone (TSH). Additionally, changes in Rab1b expression in FRTL5 cells modify the specific TSH response. Our results show, for the first time, that changes in Rab1b levels modulate gene transcription and strongly suggest that a Rab1b increase is required to elicit a secretory response.
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Affiliation(s)
- Nahuel Romero
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba 5000, Argentina
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96
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Sucic S, Koban F, El-Kasaby A, Kudlacek O, Stockner T, Sitte HH, Freissmuth M. Switching the clientele: a lysine residing in the C terminus of the serotonin transporter specifies its preference for the coat protein complex II component SEC24C. J Biol Chem 2013; 288:5330-41. [PMID: 23288844 PMCID: PMC3581386 DOI: 10.1074/jbc.m112.408237] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The serotonin transporter (SERT) maintains serotonergic neurotransmission via rapid reuptake of serotonin from the synaptic cleft. SERT relies exclusively on the coat protein complex II component SEC24C for endoplasmic reticulum (ER) export. The closely related transporters for noradrenaline and dopamine depend on SEC24D. Here, we show that discrimination between SEC24C and SEC24D is specified by the residue at position +2 downstream from the ER export motif (607RI608 in SERT). Substituting Lys610 with tyrosine, the corresponding residue found in the noradrenaline and dopamine transporters, switched the SEC24 isoform preference: SERT-K610Y relied solely on SEC24D to reach the cell surface. This analysis was extended to other SLC6 (solute carrier 6) transporter family members: siRNA-dependent depletion of SEC24C, but not of SEC24D, reduced surface levels of the glycine transporter-1a, the betaine/GABA transporter and the GABA transporter-4. Experiments with dominant negative versions of SEC24C and SEC24D recapitulated these findings. We also verified that the presence of two ER export motifs (in concatemers of SERT and GABA transporter-1) supported recruitment of both SEC24C and SEC24D. To the best of our knowledge, this is the first report to document a change in SEC24 specificity by mutation of a single residue in the client protein. Our observations allowed for deducing a rule for SLC6 family members: a hydrophobic residue (Tyr or Val) in the +2 position specifies interaction with SEC24D, and a hydrophilic residue (Lys, Asn, or Gln) recruits SEC24C. Variations in SEC24C are linked to neuropsychiatric disorders. The present findings provide a mechanistic explanation. Variations in SEC24C may translate into distinct surface levels of neurotransmitter transporters.
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Affiliation(s)
- Sonja Sucic
- Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
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97
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Abstract
Multiple studies have shown that endomembranes can act as signaling platforms for plasma-membrane-originated signaling. In particular, the Golgi complex operates as a relay station for signaling, which is initiated by classical ligand-receptor systems at the plasma membrane, acting as a positive or negative regulator of these plasma-membrane signals. Thus, the Golgi complex has emerged as a hub for intracellular signaling. Furthermore, recent evidence has indicated that the Golgi complex can also trigger its own signaling cascades, which involve some of the molecular players that are classically engaged in signal transduction at the plasma membrane. This aspect of the Golgi complex, namely, the ability to generate autonomous signaling, has been experimentally addressed only in the last few years. These studies have revealed that the transport vesicles that leave the ER for the Golgi complex also carry signal molecules that can then be sensed by a receptor in the Golgi complex to coordinate secretory organelles. The receptor involved in the sensing of incoming traffic at the Golgi complex has been shown to be the KDEL receptor (KDELR), a proposed new G-protein-coupled receptor. Upon binding to a KDEL-containing ligand (a chaperone), the KDELR can activate a signaling cascade that regulates anterograde intra-Golgi trafficking. However, this Golgi-based signaling response is only partially understood to date. Here we report on several approaches that are suitable for the study of traffic-initiated and KDELR-dependent signaling.
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98
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Cancino J, Luini A. Signaling Circuits on the Golgi Complex. Traffic 2012; 14:121-34. [DOI: 10.1111/tra.12022] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 10/12/2012] [Accepted: 10/12/2012] [Indexed: 01/21/2023]
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99
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Esteban-Pretel G, Marín MP, Romero AM, Timoneda J, Ponsoda X, Ballestín R, Renau-Piqueras J. Polyphosphoinositide metabolism and Golgi complex morphology in hippocampal neurons in primary culture is altered by chronic ethanol exposure. Alcohol Alcohol 2012; 48:15-27. [PMID: 23118092 DOI: 10.1093/alcalc/ags117] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
AIMS Ethanol affects not only the cytoskeletal organization and activity, but also intracellular trafficking in neurons in the primary culture. Polyphosphoinositide (PPIn) are essential regulators of many important cell functions, including those mentioned, cytoskeleton integrity and intracellular vesicle trafficking. Since information about the effect of chronic ethanol exposure on PPIn metabolism in neurons is scarce, this study analysed the effect of this treatment on three of these phospholipids. METHODS Phosphatidylinositol (PtdIns) levels as well as the activity and/or levels of enzymes involved in their metabolism were analysed in neurons chronically exposed to ethanol. The levels of phospholipases C and D, and phosphatidylethanol formation were also assessed. The consequence of the possible alterations in the levels of PtdIns on the Golgi complex (GC) was also analysed. RESULTS We show that phosphatidylinositol (4,5)-bisphosphate and phosphatidylinositol (3,4,5)-trisphosphate levels, both involved in the control of intracellular trafficking and cytoskeleton organization, decrease in ethanol-exposed hippocampal neurons. In contrast, several kinases that participate in the metabolism of these phospholipids, and the level and/or activity of phospholipases C and D, increase in cells after ethanol exposure. Ethanol also promotes phosphatidylethanol formation in neurons, which can result in the suppression of phosphatidic acid synthesis and, therefore, in PPIn biosynthesis. This treatment also lowers the phosphatidylinositol 4-phosphate levels, the main PPIn in the GC, with alterations in their morphology and in the levels of some of the proteins involved in structure maintenance. CONCLUSIONS The deregulation of the metabolism of PtdIns may underlie the ethanol-induced alterations on different neuronal processes, including intracellular trafficking and cytoskeletal integrity.
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Affiliation(s)
- Guillermo Esteban-Pretel
- Corresponding author: Sección de Biología y Patología Celular, Centro de Investigación, Hospital Universitario La Fe, Avda. Campanar 21, Valencia, Spain.
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100
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Ren J, Guo W. ERK1/2 regulate exocytosis through direct phosphorylation of the exocyst component Exo70. Dev Cell 2012; 22:967-78. [PMID: 22595671 DOI: 10.1016/j.devcel.2012.03.005] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Revised: 01/23/2012] [Accepted: 03/14/2012] [Indexed: 11/30/2022]
Abstract
The exocyst is a multiprotein complex essential for exocytosis and plasma membrane remodeling. The assembly of the exocyst complex mediates the tethering of post-Golgi secretory vesicles to the plasma membrane prior to fusion. Elucidating the mechanisms regulating exocyst assembly is important for the understanding of exocytosis. Here we show that the exocyst component Exo70 is a direct substrate of the extracellular signal-regulated kinases 1/2 (ERK1/2). ERK1/2 phosphorylation enhances the binding of Exo70 to other exocyst components and promotes the assembly of the exocyst complex in response to epidermal growth factor (EGF) signaling. We further demonstrate that ERK1/2 regulates exocytosis, because blocking ERK1/2 signaling by a chemical inhibitor or the expression of an Exo70 mutant defective in ERK1/2 phosphorylation inhibited exocytosis. In tumor cells, blocking Exo70 phosphorylation inhibits matrix metalloproteinase secretion and invadopodia formation. ERK1/2 phosphorylation of Exo70 may thus coordinate exocytosis with other cellular events in response to growth factor signaling.
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Affiliation(s)
- Jinqi Ren
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018, USA
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