1
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G. Dornan L, C. Simpson J. Rab6-mediated retrograde trafficking from the Golgi: the trouble with tubules. Small GTPases 2023; 14:26-44. [PMID: 37488775 PMCID: PMC10392741 DOI: 10.1080/21541248.2023.2238330] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/13/2023] [Accepted: 07/15/2023] [Indexed: 07/26/2023] Open
Abstract
Next year marks one-quarter of a century since the discovery of the so-called COPI-independent pathway, which operates between the Golgi apparatus and the endoplasmic reticulum (ER) in eukaryotic cells. Unlike almost all other intracellular trafficking pathways, this pathway is not regulated by the physical accumulation of multisubunit proteinaceous coat molecules, but instead by the small GTPase Rab6. What also sets it apart from other pathways is that the transport carriers themselves often take the form of tubules, rather than conventional vesicles. In this review, we assess the relevant literature that has accumulated to date, in an attempt to provide a concerted description of how this pathway is regulated. We discuss the possible cargo molecules that are carried in this pathway, and the likely mechanism of Rab6 tubule biogenesis, including how the cargo itself may play a critical role. We also provide perspective surrounding the various molecular motors of the kinesin, myosin and dynein families that have been implicated in driving Rab6-coated tubular membranes long distances through the cell prior to delivering their cargo to the ER. Finally, we also raise several important questions that require resolution, if we are to ultimately provide a comprehensive molecular description of how the COPI-independent pathway is controlled.
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Affiliation(s)
- Lucy G. Dornan
- Cell Screening Laboratory, UCD School of Biology & Environmental Science, University College Dublin, Dublin, Ireland
| | - Jeremy C. Simpson
- Cell Screening Laboratory, UCD School of Biology & Environmental Science, University College Dublin, Dublin, Ireland
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2
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de Los Ángeles Juricic Urzúa M, Gallardo Rojas J, Couve Correa A, Cerda M, Härtel Gründler S, González-Silva C. The Dendritic Ergic: Microtubule And Actin Cytoskeletons Participate In Stop-And-Go Movement Of Mobile Carriers Between Stable Structures. Traffic 2022; 23:174-187. [PMID: 35075729 DOI: 10.1111/tra.12832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 12/30/2021] [Accepted: 01/20/2022] [Indexed: 11/29/2022]
Abstract
The ER-to-Golgi intermediate compartment (ERGIC) is a membranous organelle that mediates protein transport between the endoplasmic reticulum (ER) and the Golgi apparatus. In neurons, clusters of these vesiculotubular structures are situated throughout the cell in proximity to the ER, passing cargo to the cis-Golgi cisternae, located mainly in the perinuclear region. Although ERGIC markers have been identified in neurons, the distribution and dynamics of neuronal ERGIC structures have not been characterized yet. Here, we show that long-distance ERGIC transport occurs via an intermittent mechanism in dendrites, with mobile elements moving between stationary structures. Slow and fast live-cell imaging have captured stable ERGIC structures remaining in place over long periods of time, as well as mobile ERGIC structures advancing very short distances along dendrites. These short distances have been consistent with the lengths between the stationary ERGIC structures. Kymography revealed ERGIC elements that moved intermittently, emerging from and fusing with stationary ERGIC structures. Interestingly, this movement apparently depends not only on the integrity of the microtubule cytoskeleton, as previously reported, but on the actin cytoskeleton as well. Our results indicate that the dendritic ERGIC has a dual nature, with both stationary and mobile structures. The neural ERGIC network transports proteins via a stop-and-go movement in which both the microtubule and the actin cytoskeletons participate. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- María de Los Ángeles Juricic Urzúa
- Neuroscience Department, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute (BNI), Santiago, Chile
| | - Javiera Gallardo Rojas
- Neuroscience Department, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute (BNI), Santiago, Chile
| | - Andrés Couve Correa
- Neuroscience Department, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute (BNI), Santiago, Chile
| | - Mauricio Cerda
- Biomedical Neuroscience Institute (BNI), Santiago, Chile.,Integrative Biology Program, Institute of Biomedical Sciences (ICBM), Center for Medical Informatics and Telemedicine (CIMT), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Steffen Härtel Gründler
- Biomedical Neuroscience Institute (BNI), Santiago, Chile.,Integrative Biology Program, Institute of Biomedical Sciences (ICBM), Center for Medical Informatics and Telemedicine (CIMT), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Carolina González-Silva
- Neuroscience Department, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute (BNI), Santiago, Chile
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3
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Branched Actin Maintains Acetylated Microtubule Network in the Early Secretory Pathway. Cells 2021; 11:cells11010015. [PMID: 35011578 PMCID: PMC8750537 DOI: 10.3390/cells11010015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 12/12/2021] [Accepted: 12/17/2021] [Indexed: 11/17/2022] Open
Abstract
In the early secretory pathway, the delivery of anterograde cargoes from the endoplasmic reticulum (ER) exit sites (ERES) to the Golgi apparatus is a multi-step transport process occurring via the ER-Golgi intermediate compartment (IC, also called ERGIC). While the role microtubules in ER-to-Golgi transport has been well established, how the actin cytoskeleton contributes to this process remains poorly understood. Here, we report that Arp2/3 inhibition affects the network of acetylated microtubules around the Golgi and induces the accumulation of unusually long RAB1/GM130-positive carriers around the centrosome. These long carriers are less prone to reach the Golgi apparatus, and arrival of anterograde cargoes to the Golgi is decreased upon Arp2/3 inhibition. Our data suggest that Arp2/3-dependent actin polymerization maintains a stable network of acetylated microtubules, which ensures efficient cargo trafficking at the late stage of ER to Golgi transport.
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4
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Kaul Z, Mookherjee D, Das S, Chatterjee D, Chakrabarti S, Chakrabarti O. Loss of tumor susceptibility gene 101 (TSG101) perturbs endoplasmic reticulum structure and function. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118741. [PMID: 32422153 DOI: 10.1016/j.bbamcr.2020.118741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 05/02/2020] [Accepted: 05/08/2020] [Indexed: 12/30/2022]
Abstract
Tumor susceptibility gene 101 (TSG101), an ESCRT-I protein, is implicated in multiple cellular processes and its functional depletion can lead to blocked lysosomal degradation, cell cycle arrest, demyelination and neurodegeneration. Here, we show that loss of TSG101 results in endoplasmic reticulum (ER) stress and this causes ER membrane remodelling (EMR). This correlates with an expansion of ER, increased vacuolation, altered relative distribution of the rough and smooth ER and disruption of three-way junctions. Blocked lysosomal degradation due to TSG101 depletion leads to ER stress and Ca2+ leakage from ER stores, causing destabilization of actin cytoskeleton. Inhibiting Ca2+ release from the ER by blocking ryanodine receptors (RYRs) with Dantrolene partially rescues the ER stress phenotypes. Hence, in this study we have identified the involvement of TSG101 in modulating ER stress mediated remodelling by engaging the actin cytoskeleton. This is significant because functional depletion of TSG101 effectuates ER-stress, perturbs the structure, mobility and function of the ER, all aspects closely associated with neurodegenerative diseases. SUMMARY STATEMENT: We show that tumor susceptibility gene (TSG) 101 regulates endoplasmic reticulum (ER) stress and its membrane remodelling. Loss of TSG101 perturbs structure, mobility and function of the ER as a consequence of actin destabilization.
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Affiliation(s)
- Zenia Kaul
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India; Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA..
| | - Debdatto Mookherjee
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India
| | - Subhrangshu Das
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, CN 6, Sector V, Salt Lake, Kolkata 700091, India
| | - Debmita Chatterjee
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India
| | - Saikat Chakrabarti
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, CN 6, Sector V, Salt Lake, Kolkata 700091, India
| | - Oishee Chakrabarti
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India; Homi Bhabha National Institute, India.
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5
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Caplan T, Lorente-Macías Á, Stogios PJ, Evdokimova E, Hyde S, Wellington MA, Liston S, Iyer KR, Puumala E, Shekhar-Guturja T, Robbins N, Savchenko A, Krysan DJ, Whitesell L, Zuercher WJ, Cowen LE. Overcoming Fungal Echinocandin Resistance through Inhibition of the Non-essential Stress Kinase Yck2. Cell Chem Biol 2020; 27:269-282.e5. [PMID: 31924499 DOI: 10.1016/j.chembiol.2019.12.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/20/2019] [Accepted: 12/17/2019] [Indexed: 01/12/2023]
Abstract
New strategies are urgently needed to counter the threat to human health posed by drug-resistant fungi. To explore an as-yet unexploited target space for antifungals, we screened a library of protein kinase inhibitors for the ability to reverse resistance of the most common human fungal pathogen, Candida albicans, to caspofungin, a widely used antifungal. This screen identified multiple 2,3-aryl-pyrazolopyridine scaffold compounds capable of restoring caspofungin sensitivity. Using chemical genomic, biochemical, and structural approaches, we established the target for our most potent compound as Yck2, a casein kinase 1 family member. Combination of this compound with caspofungin eradicated drug-resistant C. albicans infection while sparing co-cultured human cells. In mice, genetic depletion of YCK2 caused an ∼3-log10 decline in fungal burden in a model of systemic caspofungin-resistant C. albicans infection. Structural insights and our tool compound's profile in culture support targeting the Yck2 kinase function as a broadly active antifungal strategy.
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Affiliation(s)
- Tavia Caplan
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Álvaro Lorente-Macías
- Structural Genomics Consortium, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Medicinal & Organic Chemistry and Excellence Research Unit of "Chemistry Applied to Biomedicine and the Environment", Faculty of Pharmacy, University of Granada, Campus de Cartuja s/n, 18071 Granada, Spain
| | - Peter J Stogios
- Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON M5G 1M1, Canada; Center for Structural Genomics of Infectious Diseases (CSGID), Toronto, ON, M5G 1M1, Canada
| | - Elena Evdokimova
- Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON M5G 1M1, Canada; Center for Structural Genomics of Infectious Diseases (CSGID), Toronto, ON, M5G 1M1, Canada
| | - Sabrina Hyde
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Melanie A Wellington
- Departments of Pediatrics and Microbiology/Immunology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Sean Liston
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Kali R Iyer
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Emily Puumala
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Tanvi Shekhar-Guturja
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Alexei Savchenko
- Center for Structural Genomics of Infectious Diseases (CSGID), Toronto, ON, M5G 1M1, Canada; Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Damian J Krysan
- Departments of Pediatrics and Microbiology/Immunology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Luke Whitesell
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - William J Zuercher
- Structural Genomics Consortium, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada.
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6
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Weeber F, Becher A, Seibold T, Seufferlein T, Eiseler T. Concerted regulation of actin polymerization during constitutive secretion by cortactin and PKD2. J Cell Sci 2019; 132:jcs.232355. [PMID: 31727638 DOI: 10.1242/jcs.232355] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 11/07/2019] [Indexed: 12/27/2022] Open
Abstract
Constitutive secretion from the trans-Golgi-network (TGN) is facilitated by a concerted regulation of vesicle biogenesis and fission processes. The protein kinase D family (PKD) has been previously described to enhance vesicle fission by modifying the lipid environment. PKD also phosphorylates the actin regulatory protein cortactin at S298 to impair synergistic actin polymerization. We here report additional functions for PKD2 (also known as PRKD2) and cortactin in the regulation of actin polymerization during the fission of transport carriers from the TGN. Phosphorylation of cortactin at S298 impairs the interaction between WIP (also known as WIPF1) and cortactin. WIP stabilizes the autoinhibited conformation of N-WASP (also known as WASL). This leads to an inhibition of synergistic Arp2/3-complex-dependent actin polymerization at the TGN. PKD2 activity at the TGN is controlled by active CDC42-GTP which directly activates N-WASP, inhibits PKD2 and shifts the balance to non-S298-phosphorylated cortactin, which can in turn sequester WIP from N-WASP. Consequently, synergistic actin polymerization at the TGN and constitutive secretion are enhanced.
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Affiliation(s)
- Florian Weeber
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, D-89081 Ulm, Germany
| | - Alexander Becher
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, D-89081 Ulm, Germany
| | - Tanja Seibold
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, D-89081 Ulm, Germany
| | - Thomas Seufferlein
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, D-89081 Ulm, Germany
| | - Tim Eiseler
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, D-89081 Ulm, Germany
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7
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Kee AJ, Bryce NS, Yang L, Polishchuk E, Schevzov G, Weigert R, Polishchuk R, Gunning PW, Hardeman EC. ER/Golgi trafficking is facilitated by unbranched actin filaments containing Tpm4.2. Cytoskeleton (Hoboken) 2017; 74:379-389. [PMID: 28834398 DOI: 10.1002/cm.21405] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 07/31/2017] [Accepted: 08/16/2017] [Indexed: 01/14/2023]
Abstract
We have identified novel actin filaments defined by tropomyosin Tpm4.2 at the ER. EM analysis of mouse embryo fibroblasts (MEFs) isolated from mice expressing a mutant Tpm4.2 (Tpm4Plt53/Plt53 ), incapable of incorporating into actin filaments, revealed swollen ER structures compared with wild-type (WT) MEFs (Tpm4+/+ ). ER-to-Golgi, but not Golgi-to-ER trafficking was altered in the Tpm4Plt53/Plt53 MEFs following the transfection of the temperature sensitive ER-associated ts045-VSVg construct. Exogenous Tpm4.2 was able to rescue the ER-to-Golgi trafficking defect in the Tpm4Plt53/Plt53 cells. The treatment of WT MEFs with the myosin II inhibitor, blebbistatin, blocked the Tpm4.2-dependent ER-to-Golgi trafficking. The lack of an effect on ER-to-Golgi trafficking following treatment of MEFs with CK666 indicates that branched Arp2/3-containing actin filaments are not involved in anterograde vesicle trafficking. We propose that unbranched, Tpm4.2-containing filaments have an important role in maintaining ER/Golgi structure and that these structures, in conjunction with myosin II motors, mediate ER-to-Golgi trafficking.
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Affiliation(s)
- Anthony J Kee
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Nicole S Bryce
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Lingyan Yang
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Elena Polishchuk
- Telethon Institute of Genetics and Medicine, Naples 80131, Italy
| | - Galina Schevzov
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Roberto Weigert
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892
| | - Roman Polishchuk
- Telethon Institute of Genetics and Medicine, Naples 80131, Italy
| | - Peter W Gunning
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Edna C Hardeman
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
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8
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STK16 regulates actin dynamics to control Golgi organization and cell cycle. Sci Rep 2017; 7:44607. [PMID: 28294156 PMCID: PMC5353726 DOI: 10.1038/srep44607] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 02/09/2017] [Indexed: 11/30/2022] Open
Abstract
STK16 is a ubiquitously expressed, myristoylated, and palmitoylated serine/threonine protein kinase with underexplored functions. Recently, it was shown to be involved in cell division but the mechanism remains unclear. Here we found that human STK16 localizes to the Golgi complex throughout the cell cycle and plays important roles in Golgi structure regulation. STK16 knockdown or kinase inhibition disrupts actin polymers and causes fragmented Golgi in cells. In vitro assays show that STK16 directly binds to actin and regulates actin dynamics in a concentration- and kinase activity-dependent way. In addition, STK16 knockdown or kinase inhibition not only delays mitotic entry and prolongs mitosis, but also causes prometaphase and cytokinesis arrest. Therefore, we revealed STK16 as a novel actin binding protein that resides in the Golgi, which regulates actin dynamics to control Golgi structure and participate in cell cycle progression.
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9
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Targeted delivery of an ADP-ribosylating bacterial toxin into cancer cells. Sci Rep 2017; 7:41252. [PMID: 28128281 PMCID: PMC5269596 DOI: 10.1038/srep41252] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 12/19/2016] [Indexed: 12/20/2022] Open
Abstract
The actin cytoskeleton is an attractive target for bacterial toxins. The ADP-ribosyltransferase TccC3 from the insect bacterial pathogen Photorhabdus luminescence modifies actin to force its aggregation. We intended to transport the catalytic part of this toxin preferentially into cancer cells using a toxin transporter (Protective antigen, PA) which was redirected to Epidermal Growth Factor Receptors (EGFR) or to human EGF receptors 2 (HER2), which are overexpressed in several cancer cells. Protective antigen of anthrax toxin forms a pore through which the two catalytic parts (lethal factor and edema factor) or other proteins can be transported into mammalian cells. Here, we used PA as a double mutant (N682A, D683A; mPA) which cannot bind to the two natural anthrax receptors. Each mutated monomer is fused either to EGF or to an affibody directed against the human EGF receptor 2 (HER2). We established a cellular model system composed of two cell lines representing HER2 overexpressing esophageal adenocarcinomas (EACs) and EGFR overexpressing esophageal squamous cell carcinomas (ESCCs). We studied the specificity and efficiency of the re-directed anthrax pore for transport of TccC3 toxin and established Photorhabdus luminescence TccC3 as a toxin suitable for the development of a targeted toxin selectively killing cancer cells.
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10
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Petrosyan A, Casey CA, Cheng PW. The role of Rab6a and phosphorylation of non-muscle myosin IIA tailpiece in alcohol-induced Golgi disorganization. Sci Rep 2016; 6:31962. [PMID: 27535804 PMCID: PMC4989220 DOI: 10.1038/srep31962] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 07/27/2016] [Indexed: 12/12/2022] Open
Abstract
Abnormalities in the Golgi apparatus function are important to the development of alcoholic liver injury. We recently reported that Golgi disorganization in ethanol (EtOH)-treated hepatocytes is caused by impaired dimerization of the largest Golgi matrix protein, giantin. However, little is known about the mechanism which forces fragmentation. Here, in both HepG2 cells overexpressing alcohol dehydrogenase and in rat hepatocytes, we found that EtOH administration reduces the complex between giantin and Rab6a GTPase and results in the S1943 phosphorylation of non-muscle Myosin IIA (NMIIA) heavy chain, thus facilitating NMIIA association with Golgi enzymes, as detected by biochemical approaches and 3D Structured Illumination Microscopy. We revealed that NMIIA-P-S1943 competes with giantin for the Rab6a dimer, which was converted to monomer after Golgi fragmentation. Therefore, Rab6a plays a dual role in the Golgi, serving as master regulator of Golgi organization and disorganization, and that NMIIA and giantin engage in a "tug-of-war". However, the inhibition of F-actin and downregulation of NMIIA or overexpression of NMHC-IIAΔtailpiece, as well the overexpression of dominant negative Rab6a(T27N), preserved a compact Golgi phenotype. Thus, the actomyosin complex forces EtOH-induced Golgi disorganization, and the targeting of NMIIA-P-S1943 may be important for preventing the damaging effects of alcohol metabolism on the cell.
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Affiliation(s)
- Armen Petrosyan
- Department of Biochemistry and Molecular Biology, College of Medicine, the Fred and Pamela Buffett Cancer Center, 985870 Nebraska Medical Center, Omaha, NE 68198-5870, USA
| | - Carol A Casey
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, USA.,Nebraska Western Iowa Health Care System, VA Service, Department of Research Service, Omaha, NE, USA
| | - Pi-Wan Cheng
- Department of Biochemistry and Molecular Biology, College of Medicine, the Fred and Pamela Buffett Cancer Center, 985870 Nebraska Medical Center, Omaha, NE 68198-5870, USA.,Nebraska Western Iowa Health Care System, VA Service, Department of Research Service, Omaha, NE, USA
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11
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Farhat R, Séron K, Ferlin J, Fénéant L, Belouzard S, Goueslain L, Jackson CL, Dubuisson J, Rouillé Y. Identification of class II ADP-ribosylation factors as cellular factors required for hepatitis C virus replication. Cell Microbiol 2016; 18:1121-33. [PMID: 26814617 DOI: 10.1111/cmi.12572] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 01/12/2016] [Accepted: 01/21/2016] [Indexed: 12/21/2022]
Abstract
GBF1 is a host factor required for hepatitis C virus (HCV) replication. GBF1 functions as a guanine nucleotide exchange factor for G-proteins of the Arf family, which regulate membrane dynamics in the early secretory pathway and the metabolism of cytoplasmic lipid droplets. Here we established that the Arf-guanine nucleotide exchange factor activity of GBF1 is critical for its function in HCV replication, indicating that it promotes viral replication by activating one or more Arf family members. Arf involvement was confirmed with the use of two dominant negative Arf1 mutants. However, siRNA-mediated depletion of Arf1, Arf3 (class I Arfs), Arf4 or Arf5 (class II Arfs), which potentially interact with GBF1, did not significantly inhibit HCV infection. In contrast, the simultaneous depletion of both Arf4 and Arf5, but not of any other Arf pair, imposed a significant inhibition of HCV infection. Interestingly, the simultaneous depletion of both Arf4 and Arf5 had no impact on the activity of the secretory pathway and induced a compaction of the Golgi and an accumulation of lipid droplets. A similar phenotype of lipid droplet accumulation was also observed when GBF1 was inhibited by brefeldin A. In contrast, the simultaneous depletion of both Arf1 and Arf4 resulted in secretion inhibition and Golgi scattering, two actions reminiscent of GBF1 inhibition. We conclude that GBF1 could regulate different metabolic pathways through the activation of different pairs of Arf proteins.
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Affiliation(s)
- Rayan Farhat
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204, CIIL - Center for Infection and Immunity of Lille, Lille, France
| | - Karin Séron
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204, CIIL - Center for Infection and Immunity of Lille, Lille, France
| | - Juliette Ferlin
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204, CIIL - Center for Infection and Immunity of Lille, Lille, France
| | - Lucie Fénéant
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204, CIIL - Center for Infection and Immunity of Lille, Lille, France
| | - Sandrine Belouzard
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204, CIIL - Center for Infection and Immunity of Lille, Lille, France
| | - Lucie Goueslain
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204, CIIL - Center for Infection and Immunity of Lille, Lille, France.,Institut Jacques Monod, CNRS UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Catherine L Jackson
- Institut Jacques Monod, CNRS UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Jean Dubuisson
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204, CIIL - Center for Infection and Immunity of Lille, Lille, France
| | - Yves Rouillé
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204, CIIL - Center for Infection and Immunity of Lille, Lille, France
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12
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Serra-Peinado C, Sicart A, Llopis J, Egea G. Actin Filaments Are Involved in the Coupling of V0-V1 Domains of Vacuolar H+-ATPase at the Golgi Complex. J Biol Chem 2016; 291:7286-99. [PMID: 26872971 DOI: 10.1074/jbc.m115.675272] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Indexed: 11/06/2022] Open
Abstract
We previously reported that actin-depolymerizing agents promote the alkalization of the Golgi stack and thetrans-Golgi network. The main determinant of acidic pH at the Golgi is the vacuolar-type H(+)-translocating ATPase (V-ATPase), whose V1domain subunitsBandCbind actin. We have generated a GFP-tagged subunitB2construct (GFP-B2) that is incorporated into the V1domain, which in turn is coupled to the V0sector. GFP-B2 subunit is enriched at distal Golgi compartments in HeLa cells. Subcellular fractionation, immunoprecipitation, and inversal FRAP experiments show that the actin depolymerization promotes the dissociation of V1-V0domains, which entails subunitB2translocation from Golgi membranes to the cytosol. Moreover, molecular interaction between subunitsB2andC1and actin were detected. In addition, Golgi membrane lipid order disruption byd-ceramide-C6 causes Golgi pH alkalization. We conclude that actin regulates the Golgi pH homeostasis maintaining the coupling of V1-V0domains of V-ATPase through the binding of microfilaments to subunitsBandCand preserving the integrity of detergent-resistant membrane organization. These results establish the Golgi-associated V-ATPase activity as the molecular link between actin and the Golgi pH.
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Affiliation(s)
- Carla Serra-Peinado
- From the Department de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, E-08036 Barcelona
| | - Adrià Sicart
- From the Department de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, E-08036 Barcelona
| | - Juan Llopis
- the Facultad de Medicina de Albacete and Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, E-0200 Albacete, Spain
| | - Gustavo Egea
- From the Department de Biologia Cellular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, E-08036 Barcelona, the Institut d'Investigació Biomèdica August Pi i Sunyer, E-08036 Barcelona, the Institut de Nanociència i Nanotecnologia (INUB), E-08036 Barcelona, and
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13
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The trials and tubule-ations of Rab6 involvement in Golgi-to-ER retrograde transport. Biochem Soc Trans 2015; 42:1453-9. [PMID: 25233431 DOI: 10.1042/bst20140178] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In the early secretory pathway, membrane flow in the anterograde direction from the endoplasmic reticulum (ER) to the Golgi complex needs to be tightly co-ordinated with retrograde flow to maintain the size, composition and functionality of these two organelles. At least two mechanisms of transport move material in the retrograde direction: one regulated by the cytoplasmic coatomer protein I complex (COPI), and a second COPI-independent pathway utilizing the small GTP-binding protein Rab6. Although the COPI-independent pathway was discovered 15 years ago, it remains relatively poorly characterized, with only a handful of machinery molecules associated with its operation. One feature that makes this pathway somewhat unusual, and potentially difficult to study, is that the transport carriers predominantly seem to be tubular rather than vesicular in nature. This suggests that the regulatory machinery is likely to be different from that associated with vesicular transport pathways controlled by conventional coat complexes. In the present mini-review, we have highlighted the key experiments that have characterized this transport pathway so far and also have discussed the challenges that lie ahead with respect to its further characterization.
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14
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Cancino J, Capalbo A, Di Campli A, Giannotta M, Rizzo R, Jung JE, Di Martino R, Persico M, Heinklein P, Sallese M, Luini A. Control systems of membrane transport at the interface between the endoplasmic reticulum and the Golgi. Dev Cell 2014; 30:280-94. [PMID: 25117681 DOI: 10.1016/j.devcel.2014.06.018] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 04/08/2014] [Accepted: 06/23/2014] [Indexed: 10/24/2022]
Abstract
A fundamental property of cellular processes is to maintain homeostasis despite varying internal and external conditions. Within the membrane transport apparatus, variations in membrane fluxes from the endoplasmic reticulum (ER) to the Golgi complex are balanced by opposite fluxes from the Golgi to the ER to maintain homeostasis between the two organelles. Here we describe a molecular device that balances transport fluxes by integrating transduction cascades with the transport machinery. Specifically, ER-to-Golgi transport activates the KDEL receptor at the Golgi, which triggers a cascade that involves Gs and adenylyl cyclase and phosphodiesterase isoforms and then PKA activation and results in the phosphorylation of transport machinery proteins. This induces retrograde traffic to the ER and balances transport fluxes between the ER and Golgi. Moreover, the KDEL receptor activates CREB1 and other transcription factors that upregulate transport-related genes. Thus, a Golgi-based control system maintains transport homeostasis through both signaling and transcriptional networks.
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Affiliation(s)
- Jorge Cancino
- Istituto di Biochimica delle Proteine, Consiglio Nazionale delle Ricerche, Via Pietro Castellino 111, 80131 Napoli, Italy; Telethon Institute of Genetics and Medicine, Via Pietro Castellino 111, 80131 Napoli, Italy; Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Quillota 980, Viña del Mar 2520000, Chile.
| | - Anita Capalbo
- Istituto di Biochimica delle Proteine, Consiglio Nazionale delle Ricerche, Via Pietro Castellino 111, 80131 Napoli, Italy; Telethon Institute of Genetics and Medicine, Via Pietro Castellino 111, 80131 Napoli, Italy
| | - Antonella Di Campli
- Istituto di Biochimica delle Proteine, Consiglio Nazionale delle Ricerche, Via Pietro Castellino 111, 80131 Napoli, Italy
| | - Monica Giannotta
- Consorzio Mario Negri Sud, Via Nazionale 8/A, 66030 Santa Maria Imbaro (Chieti), Italy
| | - Riccardo Rizzo
- Istituto di Biochimica delle Proteine, Consiglio Nazionale delle Ricerche, Via Pietro Castellino 111, 80131 Napoli, Italy; Telethon Institute of Genetics and Medicine, Via Pietro Castellino 111, 80131 Napoli, Italy
| | - Juan E Jung
- Istituto di Biochimica delle Proteine, Consiglio Nazionale delle Ricerche, Via Pietro Castellino 111, 80131 Napoli, Italy; Istituto di Ricovero e Cura a Carattere Scientifico, Istituto di Ricerca Diagnostica e Nucleare (SDN), 80143 Napoli, Italy
| | - Rosaria Di Martino
- Istituto di Biochimica delle Proteine, Consiglio Nazionale delle Ricerche, Via Pietro Castellino 111, 80131 Napoli, Italy
| | - Maria Persico
- Istituto di Biochimica delle Proteine, Consiglio Nazionale delle Ricerche, Via Pietro Castellino 111, 80131 Napoli, Italy; Istituto di Ricovero e Cura a Carattere Scientifico, Istituto di Ricerca Diagnostica e Nucleare (SDN), 80143 Napoli, Italy
| | - Petra Heinklein
- Institut für Biochemie Charité, Universitätsmedizin Berlin, CrossOver Charitéplatz 1/Sitz, Virchowweg 6, 10117 Berlin, Germany
| | - Michele Sallese
- Consorzio Mario Negri Sud, Via Nazionale 8/A, 66030 Santa Maria Imbaro (Chieti), Italy
| | - Alberto Luini
- Istituto di Biochimica delle Proteine, Consiglio Nazionale delle Ricerche, Via Pietro Castellino 111, 80131 Napoli, Italy; Telethon Institute of Genetics and Medicine, Via Pietro Castellino 111, 80131 Napoli, Italy.
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15
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Vildanova MS, Wang W, Smirnova EA. Specific organization of Golgi apparatus in plant cells. BIOCHEMISTRY (MOSCOW) 2014; 79:894-906. [DOI: 10.1134/s0006297914090065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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16
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Romero AM, Renau-Piqueras J, Marín MP, Esteban-Pretel G. Chronic alcohol exposure affects the cell components involved in membrane traffic in neuronal dendrites. Neurotox Res 2014; 27:43-54. [PMID: 25022897 DOI: 10.1007/s12640-014-9484-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 06/13/2014] [Accepted: 07/01/2014] [Indexed: 01/09/2023]
Abstract
The specific traffic of the membrane components in neurons is a major requirement to establish and maintain neuronal domains-the axonal and the somatodendritic domains-and their polarized morphology. Unlike axons, dendrites contain membranous organelles, which are involved in the secretory pathway, including the endoplasmic reticulum, the Golgi apparatus and post-Golgi apparatus carriers, the cytoskeleton, and plasma membrane. A variety of molecules and factors are also involved in this process. Previous studies have shown that chronic alcohol exposure negatively affects several of these cell components, such as the Golgi apparatus or cytoskeleton in neurons. Yet very little information is available on the possible effects of this exposure on the remaining cell elements involved in intracellular trafficking in neurons, particularly in dendrites. By qualitative and quantitative electron microscopy, immunofluorescence and immunoblotting, we herein show that chronic exposure to moderate levels (30 mM) of ethanol in cultured neurons reduces the volume and surface density of the rough endoplasmic reticulum, and increases the levels of GRP78, a chaperone involved in endoplasmic reticulum stress. Ethanol also significantly diminishes the proportion of neurons that show an extension of Golgi into dendrites and dendritic Golgi outposts, a structure present exclusively in longer, thicker apical dendrites. Both Golgi apparatus types were also fragmented into a large number of cells. We also investigated the effect of alcohol on the levels of microtubule-based motor proteins KIF5, KIF17, KIFC2, dynein, and myosin IIb, responsible for transporting different cargoes in dendrites. Of these, alcohol differently affects several of them by lowering dynein and raising KIF5, KIFC2, and myosin IIb. These results, together with other previously published ones, suggest that practically all the protein trafficking steps in dendrites are altered to a greater or lesser extent by chronic alcohol exposure in neuronal cells, which may have negative repercussions for the development and maintenance of their polarized morphology and function.
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Affiliation(s)
- Ana M Romero
- Sección de Biología y Patología Celular, Centro de Investigación, Hospital Universitario ''La Fe'', Avenida Campanar 21, 46009, Valencia, Spain
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Study of GOLPH3: a Potential Stress-Inducible Protein from Golgi Apparatus. Mol Neurobiol 2014; 49:1449-59. [DOI: 10.1007/s12035-013-8624-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 12/16/2013] [Indexed: 10/25/2022]
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18
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Egea G, Serra-Peinado C, Salcedo-Sicilia L, Gutiérrez-Martínez E. Actin acting at the Golgi. Histochem Cell Biol 2013; 140:347-60. [PMID: 23807268 DOI: 10.1007/s00418-013-1115-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2013] [Indexed: 01/08/2023]
Abstract
The organization, assembly and remodeling of the actin cytoskeleton provide force and tracks for a variety of (endo)membrane-associated events such as membrane trafficking. This review illustrates in different cellular models how actin and many of its numerous binding and regulatory proteins (actin and co-workers) participate in the structural organization of the Golgi apparatus and in trafficking-associated processes such as sorting, biogenesis and motion of Golgi-derived transport carriers.
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Affiliation(s)
- Gustavo Egea
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, C/Casanova, 143, 08036, Barcelona, Spain.
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19
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Kvalvaag AS, Pust S, Sundet KI, Engedal N, Simm R, Sandvig K. The ERM proteins ezrin and moesin regulate retrograde Shiga toxin transport. Traffic 2013; 14:839-52. [PMID: 23593995 DOI: 10.1111/tra.12077] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 04/12/2013] [Accepted: 04/17/2013] [Indexed: 01/23/2023]
Abstract
The ERM proteins (ezrin, radixin and moesin) are known for connecting the actin cytoskeleton to the plasma membrane. They have been found to associate with lipid rafts as well as to be important for endosomal sorting and receptor signaling. However, little is known about the role of ERM proteins in retrograde transport and lipid homeostasis. In this study, we show that ezrin and moesin are important for efficient cell surface association of Shiga toxin (Stx) as well as for its retrograde transport. Furthermore, we show that depletion of these proteins influences endosomal dynamics and seems to enhance Stx transport toward lysosomes. We also show that knockdown of Vps11, a subunit of the HOPS complex, leads to increased retrograde Stx transport and reverses the inhibiting effect of ezrin and moesin knockdown. Importantly, retrograde transport of the plant toxin ricin, which binds to both glycolipids and glycoproteins with a terminal galactose, seems to be unaffected by ezrin and moesin depletion.
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Affiliation(s)
- Audun Sverre Kvalvaag
- Department of Biochemistry, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, N-0379, Oslo, Norway
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20
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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: 9.5] [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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Abstract
The Golgi complex is considered the central station of the secretory pathway where cargo proteins and lipids are properly modified, classified, packed into specific carriers and delivered to their final destinations. Early electron microscope studies showed the extraordinary structural complexity of this organelle. However, despite the large volume of incoming and outgoing traffic, it is able to maintain its architecture, although it is also flexible enough to adapt to the functional status of the cell. Many components of the molecular machinery involved in membrane traffic and other Golgi functions have been identified. However, some basic aspects of Golgi functioning remain unsolved. For instance, how cargo moves through the stack remains controversial and two classical models have been proposed: vesicular transport and cisternal maturation. Since neither of these models explains all the experimental data, a combination of these models as well as new models have been proposed. In this context, the specific role of the cisternae, vesicles and tubules needs to be clarified. In this review, we summarize our current knowledge of the Golgi organization and function, focusing on the mechanisms of intra-Golgi transport.
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22
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Petrosyan A, Cheng PW. A non-enzymatic function of Golgi glycosyltransferases: mediation of Golgi fragmentation by interaction with non-muscle myosin IIA. Glycobiology 2013; 23:690-708. [PMID: 23396488 DOI: 10.1093/glycob/cwt009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The Golgi apparatus undergoes morphological changes under stress or malignant transformation, but the precise mechanisms are not known. We recently showed that non-muscle myosin IIA (NMIIA) binds to the cytoplasmic tail of Core 2 N-acetylglucosaminyltransferase mucus-type (C2GnT-M) and transports it to the endoplasmic reticulum for recycling. Here, we report that Golgi fragmentation induced by brefeldin A (BFA) or coatomer protein (β-COP) knockdown (KD) in Panc1-bC2GnT-M (c-Myc) cells is accompanied by the increased association of NMIIA with C2GnT-M and its degradation by proteasomes. Golgi fragmentation is prevented by inhibition or KD of NMIIA. Using multiple approaches, we have shown that the speed of BFA-induced Golgi fragmentation is positively correlated with the levels of this enzyme in the Golgi. The observation is reproduced in LNCaP cells which express high levels of two endogenous glycosyltransferases--C2GnT-L and β-galactoside α2,3 sialyltransferase 1. NMIIA is found to form complexes with these two enzymes but not Golgi matrix proteins. The KD of both enzymes or the prevention of Golgi glycosyltransferases from exiting endoplasmic reticulum reduced Golgi-associated NMIIA and decreased the BFA-induced fragmentation. Interestingly, the fragmented Golgi detected in colon cancer HT-29 cells can be restored to a compact morphology after inhibition or KD of NMIIA. The Golgi disorganization induced by the microtubule or actin destructive agent is NMIIA-independent and does not affect the levels of glycosyltransferases. We conclude that NMIIA interacts with Golgi residential but not matrix proteins, and this interaction is responsible for Golgi fragmentation induced by β-COP KD or BFA treatment. This is a novel non-enzymatic function of Golgi glycosyltransferases.
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Affiliation(s)
- Armen Petrosyan
- Department of Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE 68105 USA
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23
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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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24
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Kirkbride KC, Hong NH, French CL, Clark ES, Jerome WG, Weaver AM. Regulation of late endosomal/lysosomal maturation and trafficking by cortactin affects Golgi morphology. Cytoskeleton (Hoboken) 2012; 69:625-43. [PMID: 22991200 PMCID: PMC3746372 DOI: 10.1002/cm.21051] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 07/11/2012] [Accepted: 07/11/2012] [Indexed: 01/23/2023]
Abstract
Cortactin is a branched actin regulator and tumor-overexpressed protein that promotes vesicular trafficking at a variety of cellular sites, including endosomes and the trans-Golgi network. To better understand its role in secretory trafficking, we investigated its function in Golgi homeostasis. Here, we report that knockdown (KD) of cortactin leads to a dramatic change in Golgi morphology by light microscopy, dependent on binding the Arp2/3 actin-nucleating complex. Surprisingly, there was little effect of cortactin-KD on anterograde trafficking of the constitutive cargo vesicular stomatitis virus glycoprotein (VSVG), Golgi assembly from endoplasmic reticulum membranes upon Brefeldin A washout, or Golgi ultrastructure. Instead, electron microscopy studies revealed that cortactin-KD cells contained a large number of immature-appearing late endosomal/lysosomal (LE/Lys) hybrid organelles, similar to those found in lysosomal storage diseases. Consistent with a defect in LE/Lys trafficking, cortactin-KD cells also exhibited accumulation of free cholesterol and retention of the retrograde Golgi cargo mannose-6-phosphate receptor in LE. Inhibition of LE maturation by treatment of control cells with Rab7 siRNA or chloroquine led to a compact Golgi morphology similar to that observed in cortactin-KD cells. Furthermore, the Golgi morphology defects of cortactin-KD cells could be rescued by removal of cholesterol-containing lipids from the media, suggesting that buildup of cholesterol-rich membranes in immature LE/Lys induced disturbances in retrograde trafficking. Taken together, these data reveal that LE/Lys maturation and trafficking are highly sensitive to cortactin-regulated branched actin assembly and suggests that cytoskeletal-induced Golgi morphology changes can be a consequence of altered trafficking at late endosomes.
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Affiliation(s)
- Kellye C Kirkbride
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
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25
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Bergan J, Dyve Lingelem AB, Simm R, Skotland T, Sandvig K. Shiga toxins. Toxicon 2012; 60:1085-107. [PMID: 22960449 DOI: 10.1016/j.toxicon.2012.07.016] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 06/19/2012] [Accepted: 07/25/2012] [Indexed: 02/03/2023]
Abstract
Shiga toxins are virulence factors produced by the bacteria Shigella dysenteriae and certain strains of Escherichia coli. There is currently no available treatment for disease caused by these toxin-producing bacteria, and understanding the biology of the Shiga toxins might be instrumental in addressing this issue. In target cells, the toxins efficiently inhibit protein synthesis by inactivating ribosomes, and they may induce signaling leading to apoptosis. To reach their cytoplasmic target, Shiga toxins are endocytosed and transported by a retrograde pathway to the endoplasmic reticulum, before the enzymatically active moiety is translocated to the cytosol. The toxins thereby serve as powerful tools to investigate mechanisms of intracellular transport. Although Shiga toxins are a serious threat to human health, the toxins may be exploited for medical purposes such as cancer therapy or imaging.
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Affiliation(s)
- Jonas Bergan
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Norway
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26
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Lobert VH, Stenmark H. The ESCRT machinery mediates polarization of fibroblasts through regulation of myosin light chain. J Cell Sci 2012; 125:29-36. [DOI: 10.1242/jcs.088310] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Recent evidence implicates the endosomal sorting complex required for transport (ESCRT) in the regulation of epithelial polarity in Drosophila melanogaster, but the mechanisms responsible for this action remain unclear. Here we show that ESCRTs determine cell orientation during directed migration in human fibroblasts. We find that endosomal retention of α5β1 integrin and its downstream signaling effector Src in ESCRT-depleted cells is accompanied by the failure to activate myosin light chain kinase (MLCK), which thereby cannot phosphorylate myosin regulatory light chain (MRLC). Using this mechanism, ESCRT-depleted fibroblasts fail to orient their Golgi complex to undergo directional migration and show impaired focal adhesion turnover and increased spreading on fibronectin. Consistent with these findings, expression of a phosphomimetic mutant of MRLC in ESCRT-depleted cells restores normal phenotypes during cell spreading and orientation of the Golgi. These results suggest that, through their role in regulating integrin trafficking, ESCRTs regulate phosphorylation of MRLC and, subsequently, Golgi orientation and cell spreading.
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Affiliation(s)
- Viola Hélène Lobert
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, 0316 Oslo, Norway
- Department of Biochemistry, Institute for Cancer Research, Oslo University Hospital, Montebello 0310, Oslo, Norway
- Institute for Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, 7005 Trondheim, Norway
| | - Harald Stenmark
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, 0316 Oslo, Norway
- Department of Biochemistry, Institute for Cancer Research, Oslo University Hospital, Montebello 0310, Oslo, Norway
- Institute for Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, 7005 Trondheim, Norway
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27
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Javier-Reyna R, Hernández-Ramírez V, González-Robles A, Galván-Mendoza I, Osorio-Trujillo C, Talamás-Rohana P. Rab7 and actin cytoskeleton participate during mobilization of β1EHFNR in fibronectin-stimulated Entamoeba histolyticatrophozoites. Microsc Res Tech 2011; 75:285-93. [DOI: 10.1002/jemt.21056] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 06/12/2011] [Indexed: 01/12/2023]
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Abstract
Receptor-mediated endocytosis is used by a number of viruses and toxins to gain entry into cells. Some have evolved to use specific lipids in the plasma membrane as their receptors. They include bacterial toxins such as Shiga and Cholera toxin and viruses such as mouse polyoma virus and simian virus 40. Through multivalent binding to glycosphingolipids, they induce lipid clustering and changes in membrane properties. Internalization occurs by unusual endocytic mechanisms involving lipid rafts, induction of membrane curvature, trans-bilayer coupling, and activation of signaling pathways. Once delivered to early endosomes, they follow diverse intracellular routes to the lumen of the ER, from which they penetrate into the cytosol. The role of the lipid receptors is central in these well-studied processes.
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Affiliation(s)
- Helge Ewers
- Laboratorium für Physikalische Chemie, ETH Zurich, 8093 Zurich, Switzerland
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29
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The non-catalytic carboxyl-terminal domain of ARFGAP1 regulates actin cytoskeleton reorganization by antagonizing the activation of Rac1. PLoS One 2011; 6:e18458. [PMID: 21483700 PMCID: PMC3070737 DOI: 10.1371/journal.pone.0018458] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2010] [Accepted: 03/08/2011] [Indexed: 11/26/2022] Open
Abstract
Background The regulation of the actin cytoskeleton and membrane trafficking is coordinated in mammalian cells. One of the regulators of membrane traffic, the small GTP-binding protein ARF1, also activates phosphatidylinositol kinases that in turn affect actin polymerization. ARFGAP1 is a GTPase activating protein (GAP) for ARF1 that is found on Golgi membranes. We present evidence that ARFGAP1 not only serves as a GAP for ARF1, but also can affect the actin cytoskeleton. Principal Findings As cells attach to a culture dish foci of actin appear prior to the cells flattening and spreading. We have observed that overexpression of a truncated ARFGAP1 that lacks catalytic activity for ARF, called GAP273, caused these foci to persist for much longer periods than non-transfected cells. This phenomenon was dependent on the level of GAP273 expression. Furthermore, cell spreading after re-plating or cell migration into a previously scraped area was inhibited in cells transfected with GAP273. Live cell imaging of such cells revealed that actin-rich membrane blebs formed that seldom made protrusions of actin spikes or membrane ruffles, suggesting that GAP273 interfered with the regulation of actin dynamics during cell spreading. The over-expression of constitutively active alleles of ARF6 and Rac1 suppressed the effect of GAP273 on actin. In addition, the activation of Rac1 by serum, but not that of RhoA or ARF6, was inhibited in cells over-expressing GAP273, suggesting that Rac1 is a likely downstream effector of ARFGAP1. The carboxyl terminal 65 residues of ARFGAP1 were sufficient to produce the effects on actin and cell spreading in transfected cells and co-localized with cortical actin foci. Conclusions ARFGAP1 functions as an inhibitor upstream of Rac1 in regulating actin cytoskeleton. In addition to its GAP catalytic domain and Golgi binding domain, it also has an actin regulation domain in the carboxyl-terminal portion of the protein.
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Adams HC, Chen R, Liu Z, Whitehead IP. Regulation of breast cancer cell motility by T-cell lymphoma invasion and metastasis-inducing protein. Breast Cancer Res 2010; 12:R69. [PMID: 20819206 PMCID: PMC3096956 DOI: 10.1186/bcr2637] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 09/06/2010] [Indexed: 12/25/2022] Open
Abstract
Introduction T-cell lymphoma invasion and metastasis-inducing protein (Tiam1) is an Ras-related C3 botulinum toxin substrate (Rac)-specific guanine nucleotide exchange factor that was isolated based on its ability to induce a metastatic phenotype. In polarized migrating keratinocytes, Tiam1 is found at the leading edge, where it cooperates with the protease-activated receptor 1 (Par1) complex to establish front-to-rear polarity. Although a positive correlation has been observed between Tiam1 expression and tumor grade in a variety of human malignancies, including breast, its role in breast cancer cells has not yet been examined. Methods Tiam1 expression and Rac activity were examined in a panel of human breast cancer cell lines that exhibit different degrees of cell motility. The contribution of Tiam1 to cell motility was directly examined by using transwell motility and wound-healing assays. Results Although we observed a striking, positive correlation between Tiam1 expression and cell motility in the panel of breast cancer cell lines, we did not observe a correlation between Tiam1 expression and overall levels of Rac activity. Consistent with this, small interfering ribonucleic acid (siRNA)-mediated suppression of Tiam1 expression limits the motility of cell lines in which Tiam1 expression is high (MDA-MB-231 and MDA-MB-453) but does not substantially alter the overall levels of activated Rac. Tiam1 overexpression is also not sufficient to increase the motility of more poorly motile cells (T-47D) or to increase Rac activity. Immunofluorescence and cellular fractionations indicate that Tiam1 is found predominantly in the Golgi of breast cancer cells, and in the latter case, Tiam1 was shown to co-fractionate with a limited pool of Rac1. Consistent with this Golgi localization, Tiam1 supports cell motility and Golgi reorientation in response to serum in a wound-healing assay using MDA-MB-231 and MDA-MB-435S cells. Conclusions Tiam1 expression correlates with cell motility in human breast cancer cells and is required to support the motile phenotype. Localization of endogenous Tiam1 to the Golgi, and its demonstrated role in Golgi reorientation, suggest that it may support motility through a mechanism that is discrete from its known function in leading-edge dynamics.
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Affiliation(s)
- Homer C Adams
- Department of Microbiology and Molecular Genetics, University Hospital Cancer Center, University of Medicine and Dentistry of New Jersey, Newark, 07101-1709, USA
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Sosnik J, Buffone MG, Visconti PE. Analysis of CAPZA3 localization reveals temporally discrete events during the acrosome reaction. J Cell Physiol 2010; 224:575-80. [PMID: 20458735 DOI: 10.1002/jcp.22211] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In mammals, the starting point of development is the fusion between sperm and egg. It is well established that sperm fuse with the egg through the equatorial/post-acrosomal region. Apart from this observation and the requirement of two proteins (CD9 in the egg and IZUMO1 in the sperm) very little is known about this fundamental process. Actin polymerization correlates with sperm capacitation in different mammalian species and it has been proposed that F-actin breakdown is needed during the acrosome reaction. Recently, we have presented evidence that actin polymerization inhibitors block the movement of IZUMO1 that accompany the acrosome reaction. These results suggest that actin dynamics play a role in the observed changes in IZUMO1 localization. This finding is significant because IZUMO1 localization in acrosome-intact sperm is not compatible with the known location of the initiation of the fusion between the sperm and the egg. To further understand the actin-mediated changes in protein localization during the acrosome reaction, the distribution of the sperm-specific plus-end actin capping protein CAPZA3 was analyzed. Like IZUMO1, CAPZA3 shows a dynamic pattern of localization; however, these movements follow a different temporal pattern than the changes observed with IZUMO1. In addition, the actin polymerization inhibitor latrunculin A was unable to alter CAPZA3 movement.
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Affiliation(s)
- Julian Sosnik
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, Massachusetts 01003, USA
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Castillo-Romero A, Leon-Avila G, Wang CC, Perez Rangel A, Camacho Nuez M, Garcia Tovar C, Ayala-Sumuano JT, Luna-Arias JP, Hernandez JM. Rab11 and actin cytoskeleton participate in Giardia lamblia encystation, guiding the specific vesicles to the cyst wall. PLoS Negl Trop Dis 2010; 4:e697. [PMID: 20532229 PMCID: PMC2879372 DOI: 10.1371/journal.pntd.0000697] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 04/06/2010] [Indexed: 12/30/2022] Open
Abstract
Background Giardia passes through two stages during its life cycle, the trophozoite and the cyst. Cyst formation involves the synthesis of cyst wall proteins (CWPs) and the transport of CWPs into encystation-specific vesicles (ESVs). Active vesicular trafficking is essential for encystation, but the molecular machinery driving vesicular trafficking remains unknown. The Rab proteins are involved in the targeting of vesicles to several intracellular compartments through their association with cytoskeletal motor proteins. Methodology and Principal Findings In this study, we found a relationship between Rab11 and the actin cytoskeleton in CWP1 transport. Confocal microscopy showed Rab11 was distributed throughout the entire trophozoite, while in cysts it was translocated to the periphery of the cell, where it colocalized with ESVs and microfilaments. Encystation was also accompanied by changes in rab11 mRNA expression. To evaluate the role of microfilaments in encystation, the cells were treated with latrunculin A. Scanning electron microscopy showed this treatment resulted in morphological damages to encysted parasites. The intensity of fluorescence-labeled Rab11 and CWP1 in ESVs and cyst walls was reduced, and rab11 and cwp1 mRNA levels were down-regulated. Furthermore, knocking down Rab11 with a hammerhead ribozyme resulted in an up to 80% down-regulation of rab11 mRNA. Although this knockdown did not appear lethal for trophozoites and did not affect cwp1 expression during the encystation, confocal images showed CWP1 was redistributed throughout the cytosol. Conclusions and Significance Our results indicate that Rab11 participates in the early and late encystation stages by regulating CWP1 localization and the actin-mediated transport of ESVs towards the periphery. In addition, alterations in the dynamics of actin affected rab11 and cwp1 expression. Our results provide new information about the molecules involved in Giardia encystation and suggest that Rab11 and actin may be useful as novel pharmacological targets. The encystation process is crucial for survival and transmission of Giardia lamblia to new hosts. During this process, vesicular trafficking and the cytoskeleton play important roles. In eukaryotic cells, intracellular transport is regulated by proteins, including Rab-GTPases and SNAREs, which regulate vesicle formation along with recognition of and binding to the target membrane. Cytoskeletal structures are also involved in these processes. In this study, we demonstrate the participation of Rab11 in the transport of encystation-specific vesicles (ESVs). Additionally, we demonstrate that disruption of actin microfilaments affects ESVs transport. The modification of actin dynamics was also correlated with a reduction in rab11 and cwp1 expression. Furthermore, down-regulation of rab11 mRNA by a specific hammerhead ribozyme caused nonspecific localization of CWP1. We thus provide new information about the molecular machinery that regulates Giardia lamblia encystation. Given our findings, Rab11 and actin may be useful targets to block Giardia encystation.
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Affiliation(s)
- Araceli Castillo-Romero
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, México DF, México
| | - Gloria Leon-Avila
- Departamento de Zoología, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, México DF, México
| | - Ching C. Wang
- Chemistry and Chemical Biology Graduate Program, Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America
| | - Armando Perez Rangel
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, México DF, México
| | - Minerva Camacho Nuez
- Departamento de Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, México DF, México
| | - Carlos Garcia Tovar
- Departamento de Ciencias Biológicas, FES-Cuautitlán Universidad Nacional Autónoma de México, México, México
| | | | - Juan Pedro Luna-Arias
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, México DF, México
| | - Jose Manuel Hernandez
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, México DF, México
- * E-mail:
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Protein toxins from plants and bacteria: Probes for intracellular transport and tools in medicine. FEBS Lett 2010; 584:2626-34. [DOI: 10.1016/j.febslet.2010.04.008] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Accepted: 04/07/2010] [Indexed: 01/07/2023]
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Carvou N, Holic R, Li M, Futter C, Skippen A, Cockcroft S. Phosphatidylinositol- and phosphatidylcholine-transfer activity of PITPbeta is essential for COPI-mediated retrograde transport from the Golgi to the endoplasmic reticulum. J Cell Sci 2010; 123:1262-73. [PMID: 20332109 DOI: 10.1242/jcs.061986] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vesicles formed by the COPI complex function in retrograde transport from the Golgi to the endoplasmic reticulum (ER). Phosphatidylinositol transfer protein beta (PITPbeta), an essential protein that possesses phosphatidylinositol (PtdIns) and phosphatidylcholine (PtdCho) lipid transfer activity is known to localise to the Golgi and ER but its role in these membrane systems is not clear. To examine the function of PITPbeta at the Golgi-ER interface, RNA interference (RNAi) was used to knockdown PITPbeta protein expression in HeLa cells. Depletion of PITPbeta leads to a decrease in PtdIns(4)P levels, compaction of the Golgi complex and protection from brefeldin-A-mediated dispersal to the ER. Using specific transport assays, we show that anterograde traffic is unaffected but that KDEL-receptor-dependent retrograde traffic is inhibited. This phenotype can be rescued by expression of wild-type PITPbeta but not by mutants defective in docking, PtdIns transfer and PtdCho transfer. These data demonstrate that the PtdIns and PtdCho exchange activity of PITPbeta is essential for COPI-mediated retrograde transport from the Golgi to the ER.
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Affiliation(s)
- Nicolas Carvou
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower St, London WC1E 6BT, UK
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Chen X, Simon ES, Xiang Y, Kachman M, Andrews PC, Wang Y. Quantitative proteomics analysis of cell cycle-regulated Golgi disassembly and reassembly. J Biol Chem 2010; 285:7197-207. [PMID: 20056612 DOI: 10.1074/jbc.m109.047084] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During mitosis, the stacked structure of the Golgi undergoes a continuous fragmentation process. The generated mitotic fragments are evenly distributed into the daughter cells and reassembled into new Golgi stacks. This disassembly and reassembly process is critical for Golgi biogenesis during cell division, but the underlying molecular mechanism is poorly understood. In this study, we have recapitulated this process using an in vitro assay and analyzed the proteins associated with interphase and mitotic Golgi membranes using a proteomic approach. Incubation of purified rat liver Golgi membranes with mitotic HeLa cell cytosol led to fragmentation of the membranes; subsequent treatment of these membranes with interphase cytosol allowed the reassembly of the Golgi fragments into new Golgi stacks. These membranes were then used for quantitative proteomics analyses by combining the isobaric tags for relative and absolute quantification approach with OFFGEL isoelectric focusing separation and liquid chromatography-matrix assisted laser desorption ionization-tandem mass spectrometry. In three independent experiments, a total of 1,193 Golgi-associated proteins were identified and quantified. These included broad functional categories, such as Golgi structural proteins, Golgi resident enzymes, SNAREs, Rab GTPases, cargo, and cytoskeletal proteins. More importantly, the combination of the quantitative approach with Western blotting allowed us to unveil 84 proteins with significant changes in abundance under the mitotic condition compared with the interphase condition. Among these proteins, several COPI coatomer subunits (alpha, beta, gamma, and delta) are of particular interest. Altogether, this systematic quantitative proteomic study revealed candidate proteins of the molecular machinery that control the Golgi disassembly and reassembly processes in the cell cycle.
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Affiliation(s)
- Xuequn Chen
- Department of Molecular and Integrative Physiology, The University of Michigan, Ann Arbor, Michigan 48109-1048, USA
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Sosnik J, Miranda PV, Spiridonov NA, Yoon SY, Fissore RA, Johnson GR, Visconti PE. Tssk6 is required for Izumo relocalization and gamete fusion in the mouse. J Cell Sci 2009; 122:2741-9. [PMID: 19596796 DOI: 10.1242/jcs.047225] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
One of the most important processes in fertilization is the fusion of egg and sperm; however, the molecular mechanisms involved in this process are not well understood. So far, using genetic approaches, only two proteins have been demonstrated to be necessary for this process: Izumo in sperm and CD9 in the egg. Here we demonstrate that sperm produced by Tssk6 (Sstk)-null mice present defects that prevent the successful fertilization of eggs in vitro and the fusion to zona-pellucida-free eggs. Tssk6 is a member of the testis-specific serine kinase family of proteins and is expressed postmeiotically in male germ cells. In order for fusion to occur, during the process known as acrosome reaction Izumo needs to relocate from the anterior head to other regions, including the postacrosomal compartment. Tssk6-null sperm fails to relocate Izumo during the acrosome reaction. Agents that interfere with actin dynamics blocked the acrosome-reaction-associated translocation of Izumo that is required for fusion in wild-type sperm. Additionally, actin polymerization was compromised in Tssk6-null sperm. Taken together, our results indicate that Tssk6 is involved in sperm-egg fusion through the regulation of actin polymerization and changes in Izumo localization.
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Affiliation(s)
- Julian Sosnik
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003, USA
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Fuchs YF, Eisler SA, Link G, Schlicker O, Bunt G, Pfizenmaier K, Hausser A. A Golgi PKD activity reporter reveals a crucial role of PKD in nocodazole-induced Golgi dispersal. Traffic 2009; 10:858-67. [PMID: 19416469 DOI: 10.1111/j.1600-0854.2009.00918.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The protein kinase D (PKD) family comprises multifunctional serine/threonine-specific protein kinases with three mammalian isoforms: PKD1, PKD2 and PKD3. A prominent PKD function is the regulation of basolateral-targeted transport carrier fission from the trans-Golgi network (TGN). To visualize site-specific PKD activation at this organelle, we designed a molecular reporter consisting of a PKD-specific substrate sequence fused to enhanced green fluorescent protein (EGFP), specifically targeted to the TGN via the p230 GRIP domain. Quantitative analyses using a phosphospecific antibody and ratiometric fluorescence imaging revealed that Golgi-specific phosphorylation of the reporter was strictly dependent on stimulation of endogenous PKD or transient expression of active PKD constructs. Conversely, PKD-specific pharmacological inhibitors and siRNA-mediated PKD knockdown suppressed reporter phosphorylation. Using this reporter we investigated a potential role for PKD in the regulation of Golgi complex morphology. Interestingly, nocodazole-induced Golgi complex break-up and dispersal was associated with local PKD activation as measured by reporter phosphorylation and this was efficiently blocked by expression of a dominant-negative PKD mutant or PKD depletion. Our data thus identify a novel link between PKD activity and the microtubule cytoskeleton, whereby Golgi complex integrity is regulated.
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Affiliation(s)
- Yannick F Fuchs
- Institute of Cell Biology and Immunology, University of Stuttgart, Allmandring 31, 70569 Stuttgart, Germany
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Pulvirenti T, Giannotta M, Capestrano M, Capitani M, Pisanu A, Polishchuk RS, San Pietro E, Beznoussenko GV, Mironov AA, Turacchio G, Hsu VW, Sallese M, Luini A. A traffic-activated Golgi-based signalling circuit coordinates the secretory pathway. Nat Cell Biol 2008; 10:912-22. [PMID: 18641641 DOI: 10.1038/ncb1751] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Accepted: 06/26/2008] [Indexed: 12/12/2022]
Abstract
As with other complex cellular functions, intracellular membrane transport involves the coordinated engagement of a series of organelles and machineries; however, the molecular basis of this coordination is unknown. Here we describe a Golgi-based signalling system that is activated by traffic and is involved in monitoring and balancing trafficking rates into and out of the Golgi complex. We provide evidence that the traffic signal is due to protein chaperones that leave the endoplasmic reticulum and reach the Golgi complex where they bind to the KDEL receptor. This initiates a signalling reaction that includes the activation of a Golgi pool of Src kinases and a phosphorylation cascade that in turn activates intra-Golgi trafficking, thereby maintaining the dynamic equilibrium of the Golgi complex. The concepts emerging from this study should help to understand the control circuits that coordinate high-order cellular functions.
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Affiliation(s)
- Teodoro Pulvirenti
- Laboratory of Membrane Traffic, Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, 66030 Santa Maria Imbaro (Chieti), Italy
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Lázaro-Diéguez F, Aguado C, Mato E, Sánchez-Ruíz Y, Esteban I, Alberch J, Knecht E, Egea G. Dynamics of an F-actin aggresome generated by the actin-stabilizing toxin jasplakinolide. J Cell Sci 2008; 121:1415-25. [PMID: 18398002 DOI: 10.1242/jcs.017665] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In this study, we report the formation of several cytoplasmic inclusion bodies composed of filamentous actin (F-actin) and generated by experimental treatments using depolymerizing or stabilizing actin toxins in neuronal and non-neuronal mammalian cell lines. The actin-stabilizing toxin jasplakinolide (Jpk) induced, in a microtubule-dependent manner, a single, large F-actin aggregate, which contained beta- and gamma-actin, ADF/cofilin, cortactin, and the actin nucleator Arp2/3. This aggregate was tightly associated with the Golgi complex and mitochondria, and was surrounded by vimentin intermediate filaments, microtubules and MAP4. Therefore, the Jpk-induced single, large F-actin aggregate fits the established criteria for being considered an aggresome. Lysosomes and/or autophagic vacuoles, proteasomes and microtubules were found to directly participate in the dissolution of this F-actin aggresome. Finally, the model reported here is simple, highly reproducible and reversible, and it provides an opportunity to test pharmacological agents that interfere with the formation, maintenance and/or disappearance of F-actin-enriched pathological inclusion bodies.
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Affiliation(s)
- Francisco Lázaro-Diéguez
- Departament de Biologia Cellular i Anatomia Patològica, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain
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Watabe H, Valencia JC, Le Pape E, Yamaguchi Y, Nakamura M, Rouzaud F, Hoashi T, Kawa Y, Mizoguchi M, Hearing VJ. Involvement of dynein and spectrin with early melanosome transport and melanosomal protein trafficking. J Invest Dermatol 2007; 128:162-74. [PMID: 17687388 PMCID: PMC2167631 DOI: 10.1038/sj.jid.5701019] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Melanosomes are unique membrane-bound organelles specialized for the synthesis and distribution of melanin. Mechanisms involved in the trafficking of proteins to melanosomes and in the transport of mature pigmented melanosomes to the dendrites of melanocytic cells are being characterized, but details about those processes during early stages of melanosome maturation are not well understood. Early melanosomes must remain in the perinuclear area until critical components are assembled. In this study, we characterized the processing of two distinct melanosomal proteins, tyrosinase (TYR) and Pmel17, to elucidate protein processing in early or late steps of the secretory pathway, respectively, and to determine mechanisms underlying the subcellular localization and transport of early melanosomes. We used immunological, biochemical, and molecular approaches to demonstrate that the movement of early melanosomes in the perinuclear area depends primarily on microtubules but not on actin filaments. In contrast, the trafficking of TYR and Pmel17 depends on cytoplasmic dynein and its interaction with the spectrin/ankyrin system, which is involved with the sorting of cargo from the plasma membrane. These results provide important clues toward understanding the processes involved with early events in melanosome formation and transport.
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Affiliation(s)
- Hidenori Watabe
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
- Department of Dermatology, St. Marianna University School of Medicine, Kawasaki, Japan
| | - Julio C. Valencia
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Elodie Le Pape
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Yuji Yamaguchi
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Masayuki Nakamura
- Department of Dermatology, St. Marianna University School of Medicine, Kawasaki, Japan
| | - François Rouzaud
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Toshihiko Hoashi
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Yoko Kawa
- Department of Dermatology, St. Marianna University School of Medicine, Kawasaki, Japan
| | - Masako Mizoguchi
- Department of Dermatology, St. Marianna University School of Medicine, Kawasaki, Japan
| | - Vincent J. Hearing
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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Kondylis V, van Nispen tot Pannerden HE, Herpers B, Friggi-Grelin F, Rabouille C. The golgi comprises a paired stack that is separated at G2 by modulation of the actin cytoskeleton through Abi and Scar/WAVE. Dev Cell 2007; 12:901-15. [PMID: 17543863 DOI: 10.1016/j.devcel.2007.03.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Revised: 02/02/2007] [Accepted: 03/09/2007] [Indexed: 11/19/2022]
Abstract
During the cell cycle, the Golgi, like other organelles, has to be duplicated in mass and number to ensure its correct segregation between the two daughter cells. It remains unclear, however, when and how this occurs. Here we show that in Drosophila S2 cells, the Golgi likely duplicates in mass to form a paired structure during G1/S phase and remains so until G2 when the two stacks separate, ready for entry into mitosis. We show that pairing requires an intact actin cytoskeleton which in turn depends on Abi/Scar but not WASP. This actin-dependent pairing is not limited to flies but also occurs in mammalian cells. We further show that preventing the Golgi stack separation at G2 blocks entry into mitosis, suggesting that this paired organization is part of the mitotic checkpoint, similar to what has been proposed in mammalian cells.
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Affiliation(s)
- Vangelis Kondylis
- The Cell Microscopy Centre, Department of Cell Biology, Institute of Biomembranes, University Medical Centre Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
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Hara T, Honda K, Shitashige M, Ono M, Matsuyama H, Naito K, Hirohashi S, Yamada T. Mass Spectrometry Analysis of the Native Protein Complex Containing Actinin-4 in Prostate Cancer Cells. Mol Cell Proteomics 2007; 6:479-91. [PMID: 17151021 DOI: 10.1074/mcp.m600129-mcp200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Actinin-4 was originally identified as an actin-binding protein associated with cell motility and cancer invasion and metastasis. However, actinin-4 forms complexes with a large number of different partner proteins and is speculated to have several distinct functions depending on its partner. The level of actinin-4 expression was found to be significantly lower in prostate cancer cells than in non-cancerous basal cells, and restoration of actinin-4 expression inhibited cell proliferation by prostate cancer cell line 22RV1. Immunoprecipitation and mass spectrometry analysis revealed that actinin-4 forms native complexes with several partner proteins in 22RV1 cells, including with beta/gamma-actin, calmodulin, the clathrin heavy chain, non-muscular myosin heavy chain, heterogeneous nuclear ribonucleoprotein A1, and Ras-GTPase-activating protein SH3 domain-binding protein. Clathrin is a coat protein that covers the internalized membrane pit that forms during early endocytosis. We found that other clathrin-related and unrelated cargo proteins, including dynamin, adaptin-delta, beta subunit of neuronal adaptin-like protein, and p47A, also interact with actinin-4. Immunofluorescence microscopy revealed that dynamin and clathrin co-localized with actinin-4 at the sites of membrane ruffling, and transfection of actinin-4 cDNA facilitated the transport of transferrin into perinuclear endosomes. Endocytosis terminates signaling evoked by cell surface receptors and regulates the recycling of receptors and ligands. We identified a panel of proteins whose expression and/or subcellular localization was regulated by actinin-4 by performing organelle fractionation and ICAT-LC-MS/MS. The decreased expression of actinin-4 protein in prostate cancer cells may cause aberrations in the intracellular trafficking of various cell surface molecules and contribute to carcinogenesis.
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Affiliation(s)
- Tomohiko Hara
- Chemotherapy Division and Cancer Proteomics Project, National Cancer Center Research Institute, 5-1-1 Tsukiji, Tokyo 104-0045, Japan
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Howell GJ, Holloway ZG, Cobbold C, Monaco AP, Ponnambalam S. Cell biology of membrane trafficking in human disease. ACTA ACUST UNITED AC 2007; 252:1-69. [PMID: 16984815 PMCID: PMC7112332 DOI: 10.1016/s0074-7696(06)52005-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Understanding the molecular and cellular mechanisms underlying membrane traffic pathways is crucial to the treatment and cure of human disease. Various human diseases caused by changes in cellular homeostasis arise through a single gene mutation(s) resulting in compromised membrane trafficking. Many pathogenic agents such as viruses, bacteria, or parasites have evolved mechanisms to subvert the host cell response to infection, or have hijacked cellular mechanisms to proliferate and ensure pathogen survival. Understanding the consequence of genetic mutations or pathogenic infection on membrane traffic has also enabled greater understanding of the interactions between organisms and the surrounding environment. This review focuses on human genetic defects and molecular mechanisms that underlie eukaryote exocytosis and endocytosis and current and future prospects for alleviation of a variety of human diseases.
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Affiliation(s)
- Gareth J Howell
- Endothelial Cell Biology Unit, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
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Lázaro-Diéguez F, Jiménez N, Barth H, Koster AJ, Renau-Piqueras J, Llopis JL, Burger KNJ, Egea G. Actin filaments are involved in the maintenance of Golgi cisternae morphology and intra-Golgi pH. ACTA ACUST UNITED AC 2007; 63:778-91. [PMID: 16960891 DOI: 10.1002/cm.20161] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Here we examine the contribution of actin dynamics to the architecture and pH of the Golgi complex. To this end, we have used toxins that depolymerize (cytochalasin D, latrunculin B, mycalolide B, and Clostridium botulinum C2 toxin) or stabilize (jasplakinolide) filamentous actin. When various clonal cell lines were examined by epifluorescence microscopy, all of these actin toxins induced compaction of the Golgi complex. However, ultrastructural analysis by transmission electron microscopy and electron tomography/three-dimensional modelling of the Golgi complex showed that F-actin depolymerization first induces perforation/fragmentation and severe swelling of Golgi cisternae, which leads to a completely disorganized structure. In contrast, F-actin stabilization results only in cisternae perforation/fragmentation. Concomitantly to actin depolymerization-induced cisternae swelling and disorganization, the intra-Golgi pH significantly increased. Similar ultrastructural and Golgi pH alkalinization were observed in cells treated with the vacuolar H+ -ATPases inhibitors bafilomycin A1 and concanamycin A. Overall, these results suggest that actin filaments are implicated in the preservation of the flattened shape of Golgi cisternae. This maintenance seems to be mediated by the regulation of the state of F-actin assembly on the Golgi pH homeostasis.
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Affiliation(s)
- Francisco Lázaro-Diéguez
- Departament de Biologia Cellular i Anatomia Patològica, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
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Suvanasuthi S, Tamai K, Kaneda Y. Rapid transport of plasmid DNA into the nucleolus via actin depolymerization using the HVJ envelope vector. J Gene Med 2007; 9:55-62. [PMID: 17149789 DOI: 10.1002/jgm.989] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Although nuclear transport of therapeutic genes is an essential requirement of human gene therapy, factors required for nuclear entry of DNA remain to be elucidated. Non-viral vector systems have led to numerous improvements in the efficiency of delivery of exogenous DNA into cells. However, nuclear transport of plasmid is difficult to achieve. METHODS We examined nuclear translocation efficiency of Cy3-labeled plasmid DNA (Cy3-pDNA) delivered by the hemagglutinating virus of Japan envelope (HVJ-E) vector, Lipofectamine or microinjection. We also examined the effect of actin depolymerization on nuclear transport of Cy3-pDNA. RESULTS Cy3-pDNA reached the nucleus, particularly in the nucleolus, in 30 min after fusion-mediated delivery using the HVJ-E vector, while the DNA was retained in the cytoplasm during the observed period after the delivery by cationic liposomes. HVJ-E treatment transiently depolymerized actin filaments, and acceleration of nucleolar entry of microinjected DNA was achieved when treated with either empty HVJ-E or cytochalasin D, an inhibitor of actin depolymerization, prior to microinjection. CONCLUSIONS These results suggest that plasmid DNA can be transported rapidly from the cytoplasm to the nucleolus when actin filaments are depolymerized. Thus, the HVJ-E vector can accelerate the transport of DNA to the nucleolus by actin depolymerization.
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Affiliation(s)
- Saroj Suvanasuthi
- Division of Gene Therapy Science, Graduate School of Medicine, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan
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Vogelsgesang M, Pautsch A, Aktories K. C3 exoenzymes, novel insights into structure and action of Rho-ADP-ribosylating toxins. Naunyn Schmiedebergs Arch Pharmacol 2006; 374:347-60. [PMID: 17146673 DOI: 10.1007/s00210-006-0113-y] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2006] [Accepted: 10/18/2006] [Indexed: 12/19/2022]
Abstract
The family of C3-like exoenzymes comprises seven bacterial ADP-ribosyltransferases of different origin. The common hallmark of these exoenzymes is the selective N-ADP-ribosylation of the low molecular mass GTP-binding proteins RhoA, B, and C and inhibition of signal pathways controlled by Rho GTPases. Therefore, C3-like exoenzymes were applied as pharmacological tools for analyses of cellular functions of Rho protein in numerous studies. Recent structural and functional analyses of C3-like exoenzymes provide detailed information on the molecular mechanisms and functional consequences of ADP-ribosylation catalyzed by these toxins. More recently additional non-enzymatic actions of C3-like ADP-ribosyltransferases have been identified showing that C3 transferases from Clostridium botulinum and Clostridium limosum form a GDI-like complex with the Ras-like low molecular mass GTPase Ral without ADP-ribosylation. These results add novel information on the molecular mode of action(s) of C3-like exoenzymes and are discussed in this review.
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Affiliation(s)
- Martin Vogelsgesang
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-University Freiburg, Otto-Krayer-Haus, Albertstrasse 25, Freiburg, Germany
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Jensen HL. Herpes simplex virus type 1 morphogenesis and virus-cell interactions: significance of cytoskeleton and methodological aspects. APMIS 2006:7-55. [PMID: 16930175 DOI: 10.1111/j.1600-0463.2006.apm_v114_s119.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Abstract
The ADP-ribosylation factor (ARF) small GTPases regulate vesicular traffic and organelle structure by recruiting coat proteins, regulating phospholipid metabolism and modulating the structure of actin at membrane surfaces. Recent advances in our understanding of the signalling pathways that are regulated by ARF1 and ARF6, two of the best characterized ARF proteins, provide a molecular context for ARF protein function in fundamental biological processes, such as secretion, endocytosis, phagocytosis, cytokinesis, cell adhesion and tumour-cell invasion.
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Affiliation(s)
- Crislyn D'Souza-Schorey
- Department of Biological Sciences and the Walther Cancer Institute, University of Notre Dame, Notre Dame, Indiana, USA.
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Abstract
In skeletal muscle and adipose tissue, insulin-stimulated glucose uptake is dependent upon translocation of the insulin-responsive glucose transporter GLUT4 from intracellular storage compartments to the plasma membrane. This insulin-induced redistribution of GLUT4 protein is achieved through a series of highly organized membrane trafficking events, orchestrated by insulin receptor signals. Recently, several key molecules linking insulin receptor signals and membrane trafficking have been identified, and emerging evidence supports the importance of subcellular compartmentalization of signaling components at the right time and in the right place. In addition, the translocation of GLUT4 in adipocytes requires insulin stimulation of dynamic actin remodeling at the inner surface of the plasma membrane (cortical actin) and in the perinuclear region. This results from at least two independent insulin receptor signals, one leading to the activation of phosphatidylinositol (PI) 3-kinase and the other to the activation of the Rho family small GTP-binding protein TC10. Thus, both spatial and temporal regulations of actin dynamics, both beneath the plasma membrane and around endomembranes, by insulin receptor signals are also involved in the process of GLUT4 translocation.
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Affiliation(s)
- Makoto Kanzaki
- TUBERO/Tohoku University Biomedical Engineering Research Organization, Tohoku University, Sendai, Japan
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Kessels MM, Dong J, Leibig W, Westermann P, Qualmann B. Complexes of syndapin II with dynamin II promote vesicle formation at the trans-Golgi network. J Cell Sci 2006; 119:1504-16. [PMID: 16551695 DOI: 10.1242/jcs.02877] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The role of dynamin and so-called accessory proteins in endocytosis is well established. However, molecular details of the function(s) of dynamin II at the Golgi are largely unclear. We demonstrate that the ubiquitously expressed syndapin II isoform interacts with the proline-rich domain (PRD) of dynamin II through its Src-homology 3 (SH3) domain. Co-immunoprecipitation of endogenous syndapin II and dynamin II, and successful reconstitutions of such complexes at membranes in COS-7 cells, show the in vivo relevance of the interaction. Syndapin II can associate with Golgi membranes and this association increases upon Golgi exit block. Brefeldin A treatment clearly shows that the observed perinuclear localization of syndapin II co-localizing with syntaxin 6 reflects the Golgi complex and that it requires functional integrity of the Golgi. Syndapins are crucial for Golgi vesicle formation because anti-syndapin antibodies, used either in in vitro reconstitutions or in living cells, inhibited this process. Both types of assays additionally revealed the essential role of syndapin II SH3 interactions with the dynamin II PRD in vesicle formation. An excess of the syndapin SH3 domain strongly inhibited budding from Golgi membranes in vitro. Likewise, overexpression of the syndapin SH3 domain or of a dynamin II variant incapable of associating with syndapin II (dynamin IIΔPRD) impaired trafficking of vesicular stomatitis virus glycoprotein (VSVG)-GFP in vivo. By contrast, full-length syndapin II-l had no negative effect, and instead promoted VSVG-GFP export from the Golgi. Importantly, a cytosolic fraction containing endogenous syndapin-dynamin complexes was sufficient to promote vesicle formation from Golgi membranes in a syndapin-dependent manner. Thus, syndapin-dynamin complexes are crucial and sufficient to promote vesicle formation from the trans-Golgi network.
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Affiliation(s)
- Michael M Kessels
- Department of Neurochemistry and Molecular Biology, AG Membrane Trafficking and Cytoskeleton, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
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