51
|
Moreiras H, Seabra MC, Barral DC. Melanin Transfer in the Epidermis: The Pursuit of Skin Pigmentation Control Mechanisms. Int J Mol Sci 2021; 22:4466. [PMID: 33923362 PMCID: PMC8123122 DOI: 10.3390/ijms22094466] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 12/27/2022] Open
Abstract
The mechanisms by which the pigment melanin is transferred from melanocytes and processed within keratinocytes to achieve skin pigmentation remain ill-characterized. Nevertheless, several models have emerged in the past decades to explain the transfer process. Here, we review the proposed models for melanin transfer in the skin epidermis, the available evidence supporting each one, and the recent observations in favor of the exo/phagocytosis and shed vesicles models. In order to reconcile the transfer models, we propose that different mechanisms could co-exist to sustain skin pigmentation under different conditions. We also discuss the limited knowledge about melanin processing within keratinocytes. Finally, we pinpoint new questions that ought to be addressed to solve the long-lasting quest for the understanding of how basal skin pigmentation is controlled. This knowledge will allow the emergence of new strategies to treat pigmentary disorders that cause a significant socio-economic burden to patients and healthcare systems worldwide and could also have relevant cosmetic applications.
Collapse
Affiliation(s)
| | | | - Duarte C. Barral
- iNOVA4Health, CEDOC, NOVA Medical School, NMS, Universidade NOVA de Lisboa, 1169-056 Lisboa, Portugal; (H.M.); (M.C.S.)
| |
Collapse
|
52
|
Liu M, Hu J, Zhang A, Dai Y, Chen W, He Y, Zhang H, Zheng X, Zhang Z. Auxilin-like protein MoSwa2 promotes effector secretion and virulence as a clathrin uncoating factor in the rice blast fungus Magnaporthe oryzae. THE NEW PHYTOLOGIST 2021; 230:720-736. [PMID: 33423301 PMCID: PMC8048681 DOI: 10.1111/nph.17181] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 01/04/2021] [Indexed: 05/03/2023]
Abstract
Plant pathogens exploit the extracellular matrix (ECM) to inhibit host immunity during their interactions with the host. The formation of ECM involves a series of continuous steps of vesicular transport events. To understand how such vesicle trafficking impacts ECM and virulence in the rice blast fungus Magnaporthe oryzae, we characterised MoSwa2, a previously identified actin-regulating kinase MoArk1 interacting protein, as an orthologue of the auxilin-like clathrin uncoating factor Swa2 of the budding yeast Saccharomyces cerevisiae. We found that MoSwa2 functions as an uncoating factor of the coat protein complex II (COPII) via an interaction with the COPII subunit MoSec24-2. Loss of MoSwa2 led to a deficiency in the secretion of extracellular proteins, resulting in both restricted growth of invasive hyphae and reduced inhibition of host immunity. Additionally, extracellular fluid (ECF) proteome analysis revealed that MoSwa2-regulated extracellular proteins include many redox proteins such as the berberine bridge enzyme-like (BBE-like) protein MoSef1. We further found that MoSef1 functions as an apoplastic virulent factor that inhibits the host immune response. Our studies revealed a novel function of a COPII uncoating factor in vesicular transport that is critical in the suppression of host immunity and pathogenicity of M. oryzae.
Collapse
Affiliation(s)
- Muxing Liu
- Department of Plant PathologyCollege of Plant ProtectionNanjing Agricultural UniversityKey Laboratory of Integrated Management of Crop Diseases and PestsMinistry of EducationNanjing210095China
- The Key Laboratory of Plant ImmunityNanjing Agricultural UniversityNanjing210095China
| | - Jiexiong Hu
- Department of Plant PathologyCollege of Plant ProtectionNanjing Agricultural UniversityKey Laboratory of Integrated Management of Crop Diseases and PestsMinistry of EducationNanjing210095China
| | - Ao Zhang
- Department of Plant PathologyCollege of Plant ProtectionNanjing Agricultural UniversityKey Laboratory of Integrated Management of Crop Diseases and PestsMinistry of EducationNanjing210095China
| | - Ying Dai
- Department of Plant PathologyCollege of Plant ProtectionNanjing Agricultural UniversityKey Laboratory of Integrated Management of Crop Diseases and PestsMinistry of EducationNanjing210095China
| | - Weizhong Chen
- Department of Plant PathologyCollege of Plant ProtectionNanjing Agricultural UniversityKey Laboratory of Integrated Management of Crop Diseases and PestsMinistry of EducationNanjing210095China
| | - Yanglan He
- Department of Plant PathologyCollege of Plant ProtectionNanjing Agricultural UniversityKey Laboratory of Integrated Management of Crop Diseases and PestsMinistry of EducationNanjing210095China
| | - Haifeng Zhang
- Department of Plant PathologyCollege of Plant ProtectionNanjing Agricultural UniversityKey Laboratory of Integrated Management of Crop Diseases and PestsMinistry of EducationNanjing210095China
| | - Xiaobo Zheng
- Department of Plant PathologyCollege of Plant ProtectionNanjing Agricultural UniversityKey Laboratory of Integrated Management of Crop Diseases and PestsMinistry of EducationNanjing210095China
| | - Zhengguang Zhang
- Department of Plant PathologyCollege of Plant ProtectionNanjing Agricultural UniversityKey Laboratory of Integrated Management of Crop Diseases and PestsMinistry of EducationNanjing210095China
- The Key Laboratory of Plant ImmunityNanjing Agricultural UniversityNanjing210095China
| |
Collapse
|
53
|
Yatsenko AS, Kucherenko MM, Xie Y, Urlaub H, Shcherbata HR. Exocyst-mediated membrane trafficking of the lissencephaly-associated ECM receptor dystroglycan is required for proper brain compartmentalization. eLife 2021; 10:63868. [PMID: 33620318 PMCID: PMC7929561 DOI: 10.7554/elife.63868] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 02/23/2021] [Indexed: 12/14/2022] Open
Abstract
To assemble a brain, differentiating neurons must make proper connections and establish specialized brain compartments. Abnormal levels of cell adhesion molecules disrupt these processes. Dystroglycan (Dg) is a major non-integrin cell adhesion receptor, deregulation of which is associated with dramatic neuroanatomical defects such as lissencephaly type II or cobblestone brain. The previously established Drosophila model for cobblestone lissencephaly was used to understand how Dg is regulated in the brain. During development, Dg has a spatiotemporally dynamic expression pattern, fine-tuning of which is crucial for accurate brain assembly. In addition, mass spectrometry analyses identified numerous components associated with Dg in neurons, including several proteins of the exocyst complex. Data show that exocyst-based membrane trafficking of Dg allows its distinct expression pattern, essential for proper brain morphogenesis. Further studies of the Dg neuronal interactome will allow identification of new factors involved in the development of dystroglycanopathies and advance disease diagnostics in humans.
Collapse
Affiliation(s)
- Andriy S Yatsenko
- Institute of Cell Biochemistry, Hannover Medical School, Hannover, Germany
| | - Mariya M Kucherenko
- Max Planck Research Group of Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Yuanbin Xie
- Max Planck Research Group of Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Research Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,University Medical Center Göttingen, Bioanalytics, Institute for Clinical Chemistry, Göttingen, Germany
| | - Halyna R Shcherbata
- Institute of Cell Biochemistry, Hannover Medical School, Hannover, Germany.,Max Planck Research Group of Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| |
Collapse
|
54
|
Lira M, Zamorano P, Cerpa W. Exo70 intracellular redistribution after repeated mild traumatic brain injury. Biol Res 2021; 54:5. [PMID: 33593425 PMCID: PMC7885507 DOI: 10.1186/s40659-021-00329-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 02/03/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Exo70 is a subunit of the greater exocyst complex, a collection of proteins that oversees cellular membrane addition and polarized exocytosis by acting as a tethering intermediate between the plasma membrane and newly synthesized secretory vesicles. Although Exo70 function has been implicated in several developmental events including cytokinesis and the establishment of cell polarity, its role in neuropathologies is poorly understood. On the other hand, traumatic brain injury is the result of mechanical external force including contusion, fast acceleration, and expansive waves that produce temporal or permanent cognitive damage and triggers physical and psychosocial alterations including headache, memory problems, attention deficits, difficulty thinking, mood swings, and frustration. Traumatic brain injury is a critical health problem on a global scale, constituting a major cause of deaths and disability among young adults. Trauma-related cellular damage includes redistribution of N-methyl-D-aspartate receptors outside of the synaptic compartment triggering detrimental effects to neurons. The exocyst has been related to glutamate receptor constitutive trafficking/delivery towards synapse as well. This work examines whether the exocyst complex subunit Exo70 participates in traumatic brain injury and if it is redistributed among subcellular compartments RESULTS: Our analysis shows that Exo70 expression is not altered upon injury induction. By using subcellular fractionation, we determined that Exo70 is redistributed from microsomes fraction into the synaptic compartment after brain trauma. In the synaptic compartment, we also show that the exocyst complex assembly and its interaction with GluN2B are increased. Finally, we show that the Exo70 pool that is redistributed comes from the plasma membrane. CONCLUSIONS The present findings position Exo70 in the group of proteins that could modulate GluN2B synaptic availability in acute neuropathology like a traumatic brain injury. By acting as a nucleator factor, Exo70 is capable of redirecting the ensembled complex into the synapse. We suggest that this redistribution is part of a compensatory mechanism by which Exo70 is able to maintain GluN2B partially on synapses. Hence, reducing the detrimental effects associated with TBI pathophysiology.
Collapse
Affiliation(s)
- Matías Lira
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O´Higgins 340, Santiago, Chile
| | - Pedro Zamorano
- Departamento Biomédico, Universidad de Antofagasta, Antofagasta, Chile.,Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Waldo Cerpa
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O´Higgins 340, Santiago, Chile. .,Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile.
| |
Collapse
|
55
|
Orr RG, Furt F, Warner EL, Agar EM, Garbarino JM, Cabral SE, Dubuke ML, Butt AM, Munson M, Vidali L. Rab-E and its interaction with myosin XI are essential for polarised cell growth. THE NEW PHYTOLOGIST 2021; 229:1924-1936. [PMID: 33098085 PMCID: PMC8168425 DOI: 10.1111/nph.17023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 10/12/2020] [Indexed: 05/07/2023]
Abstract
The fundamental process of polarised exocytosis requires the interconnected activity of molecular motors trafficking vesicular cargo within a dynamic cytoskeletal network. In plants, few mechanistic details are known about how molecular motors, such as myosin XI, associate with their secretory cargo to support the ubiquitous processes of polarised growth and cell division. Live-cell imaging coupled with targeted gene knockouts and a high-throughput RNAi assay enabled the first characterisation of the loss of Rab-E function. Yeast two-hybrid and subsequent in silico structural prediction uncovered a specific interaction between Rab-E and myosin XI that is conserved between P. patens and A. thaliana. Rab-E co-localises with myosin XI at sites of active exocytosis, and at the growing tip both proteins are spatiotemporally coupled. Rab-E is required for normal plant growth in P. patens and the rab-E and myosin XI phenotypes are rescued by A. thaliana's Rab-E1c and myosin XI-K/E, respectively. Both PpMyoXI and AtMyoXI-K interact with PpRabE14, and the interaction is specifically mediated by PpMyoXI residue V1422. This interaction is required for polarised growth. Our results suggest that the interaction of Rab-E and myosin XI is a conserved feature of polarised growth in plants.
Collapse
Affiliation(s)
- Robert G Orr
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Fabienne Furt
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Erin L Warner
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Erin M Agar
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Jennifer M Garbarino
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Sarah E Cabral
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Michelle L Dubuke
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Allison M Butt
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Mary Munson
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Luis Vidali
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| |
Collapse
|
56
|
de la Riva-Carrasco R, Perez-Pandolfo S, Suárez Freire S, Romero NM, Bhujabal Z, Johansen T, Wappner P, Melani M. The immunophilin Zonda controls regulated exocytosis in endocrine and exocrine tissues. Traffic 2021; 22:111-122. [PMID: 33336828 DOI: 10.1111/tra.12777] [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: 06/28/2020] [Revised: 12/15/2020] [Accepted: 12/15/2020] [Indexed: 11/30/2022]
Abstract
Exocytosis is a fundamental process in physiology, that ensures communication between cells, organs and even organisms. Hormones, neuropeptides and antibodies, among other cargoes are packed in exocytic vesicles that need to reach and fuse with the plasma membrane to release their content to the extracellular milieu. Hundreds of proteins participate in this process and several others in its regulation. We report here a novel component of the exocytic machinery, the Drosophila transmembrane immunophilin Zonda (Zda), previously found to participate in autophagy. Zda is highly expressed in secretory tissues, and regulates exocytosis in at least three of them: the ring gland, insulin-producing cells and the salivary gland. Using the salivary gland as a model system, we found that Zda is required at final steps of the exocytic process for fusion of secretory granules to the plasma membrane. In a genetic screen we identified the small GTPase RalA as a crucial regulator of secretory granule exocytosis that is required, similarly to Zda, for fusion between the secretory granule and the plasma membrane.
Collapse
Affiliation(s)
| | - Sebastián Perez-Pandolfo
- Laboratorio de Genética y Fisiología Molecular, Fundación Instituto Leloir, Buenos Aires, Argentina
| | - Sofía Suárez Freire
- Laboratorio de Genética y Fisiología Molecular, Fundación Instituto Leloir, Buenos Aires, Argentina
| | - Nuria M Romero
- Université Côte d'Azur, INRA, CNRS, Institut Sophia Agrobiotech, Sophia Antipolis, France
| | - Zambarlal Bhujabal
- Molecular Cancer Research Group, Department of Medical Biology, University of Tromsø-The Arctic University of Norway, Tromsø, Norway
| | - Terje Johansen
- Molecular Cancer Research Group, Department of Medical Biology, University of Tromsø-The Arctic University of Norway, Tromsø, Norway
| | - Pablo Wappner
- Laboratorio de Genética y Fisiología Molecular, Fundación Instituto Leloir, Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.,Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Mariana Melani
- Laboratorio de Genética y Fisiología Molecular, Fundación Instituto Leloir, Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| |
Collapse
|
57
|
Saccomanno A, Potocký M, Pejchar P, Hála M, Shikata H, Schwechheimer C, Žárský V. Regulation of Exocyst Function in Pollen Tube Growth by Phosphorylation of Exocyst Subunit EXO70C2. FRONTIERS IN PLANT SCIENCE 2021; 11:609600. [PMID: 33519861 PMCID: PMC7840542 DOI: 10.3389/fpls.2020.609600] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 12/22/2020] [Indexed: 06/12/2023]
Abstract
Exocyst is a heterooctameric protein complex crucial for the tethering of secretory vesicles to the plasma membrane during exocytosis. Compared to other eukaryotes, exocyst subunit EXO70 is represented by many isoforms in land plants whose cell biological and biological roles, as well as modes of regulation remain largely unknown. Here, we present data on the phospho-regulation of exocyst isoform EXO70C2, which we previously identified as a putative negative regulator of exocyst function in pollen tube growth. A comprehensive phosphoproteomic analysis revealed phosphorylation of EXO70C2 at multiple sites. We have now performed localization and functional studies of phospho-dead and phospho-mimetic variants of Arabidopsis EXO70C2 in transiently transformed tobacco pollen tubes and stably transformed Arabidopsis wild type and exo70C2 mutant plants. Our data reveal a dose-dependent effect of AtEXO70C2 overexpression on pollen tube growth rate and cellular architecture. We show that changes of the AtEXO70C2 phosphorylation status lead to distinct outcomes in wild type and exo70c2 mutant cells, suggesting a complex regulatory pattern. On the other side, phosphorylation does not affect the cytoplasmic localization of AtEXO70C2 or its interaction with putative secretion inhibitor ROH1 in the yeast two-hybrid system.
Collapse
Affiliation(s)
- Antonietta Saccomanno
- Laboratory of Cell Biology, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Martin Potocký
- Laboratory of Cell Biology, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Přemysl Pejchar
- Laboratory of Cell Biology, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Michal Hála
- Laboratory of Cell Biology, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Hiromasa Shikata
- Plant Systems Biology, Technische Universität München, Freising, Germany
| | | | - Viktor Žárský
- Laboratory of Cell Biology, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| |
Collapse
|
58
|
Apken LH, Oeckinghaus A. The RAL signaling network: Cancer and beyond. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2020; 361:21-105. [PMID: 34074494 DOI: 10.1016/bs.ircmb.2020.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The RAL proteins RALA and RALB belong to the superfamily of small RAS-like GTPases (guanosine triphosphatases). RAL GTPases function as molecular switches in cells by cycling through GDP- and GTP-bound states, a process which is regulated by several guanine exchange factors (GEFs) and two heterodimeric GTPase activating proteins (GAPs). Since their discovery in the 1980s, RALA and RALB have been established to exert isoform-specific functions in central cellular processes such as exocytosis, endocytosis, actin organization and gene expression. Consequently, it is not surprising that an increasing number of physiological functions are discovered to be controlled by RAL, including neuronal plasticity, immune response, and glucose and lipid homeostasis. The critical importance of RAL GTPases for oncogenic RAS-driven cellular transformation and tumorigenesis still attracts most research interest. Here, RAL proteins are key drivers of cell migration, metastasis, anchorage-independent proliferation, and survival. This chapter provides an overview of normal and pathological functions of RAL GTPases and summarizes the current knowledge on the involvement of RAL in human disease as well as current therapeutic targeting strategies. In particular, molecular mechanisms that specifically control RAL activity and RAL effector usage in different scenarios are outlined, putting a spotlight on the complexity of the RAL GTPase signaling network and the emerging theme of RAS-independent regulation and relevance of RAL.
Collapse
Affiliation(s)
- Lisa H Apken
- Institute of Molecular Tumor Biology, Faculty of Medicine, University of Münster, Münster, Germany
| | - Andrea Oeckinghaus
- Institute of Molecular Tumor Biology, Faculty of Medicine, University of Münster, Münster, Germany.
| |
Collapse
|
59
|
Cascallares M, Setzes N, Marchetti F, López GA, Distéfano AM, Cainzos M, Zabaleta E, Pagnussat GC. A Complex Journey: Cell Wall Remodeling, Interactions, and Integrity During Pollen Tube Growth. FRONTIERS IN PLANT SCIENCE 2020; 11:599247. [PMID: 33329663 PMCID: PMC7733995 DOI: 10.3389/fpls.2020.599247] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 11/02/2020] [Indexed: 05/05/2023]
Abstract
In flowering plants, pollen tubes undergo a journey that starts in the stigma and ends in the ovule with the delivery of the sperm cells to achieve double fertilization. The pollen cell wall plays an essential role to accomplish all the steps required for the successful delivery of the male gametes. This extended path involves female tissue recognition, rapid hydration and germination, polar growth, and a tight regulation of cell wall synthesis and modification, as its properties change not only along the pollen tube but also in response to guidance cues inside the pistil. In this review, we focus on the most recent advances in elucidating the molecular mechanisms involved in the regulation of cell wall synthesis and modification during pollen germination, pollen tube growth, and rupture.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Gabriela Carolina Pagnussat
- Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata, CONICET, Mar del Plata, Argentina
| |
Collapse
|
60
|
Chung CG, Park SS, Park JH, Lee SB. Dysregulated Plasma Membrane Turnover Underlying Dendritic Pathology in Neurodegenerative Diseases. Front Cell Neurosci 2020; 14:556461. [PMID: 33192307 PMCID: PMC7580253 DOI: 10.3389/fncel.2020.556461] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 09/03/2020] [Indexed: 12/29/2022] Open
Abstract
Due to their enormous surface area compared to other cell types, neurons face unique challenges in properly handling supply and retrieval of the plasma membrane (PM)-a process termed PM turnover-in their distal areas. Because of the length and extensiveness of dendritic branches in neurons, the transport of materials needed for PM turnover from soma to distal dendrites will be inefficient and quite burdensome for somatic organelles. To meet local demands, PM turnover in dendrites most likely requires local cellular machinery, such as dendritic endocytic and secretory systems, dysregulation of which may result in dendritic pathology observed in various neurodegenerative diseases (NDs). Supporting this notion, a growing body of literature provides evidence to suggest the pathogenic contribution of dysregulated PM turnover to dendritic pathology in certain NDs. In this article, we present our perspective view that impaired dendritic endocytic and secretory systems may contribute to dendritic pathology by encumbering PM turnover in NDs.
Collapse
Affiliation(s)
- Chang Geon Chung
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| | - Sung Soon Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| | - Jeong Hyang Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| | - Sung Bae Lee
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| |
Collapse
|
61
|
Fan T, Sun N, He J. Exosome-Derived LncRNAs in Lung Cancer. Front Oncol 2020; 10:1728. [PMID: 33072553 PMCID: PMC7538687 DOI: 10.3389/fonc.2020.01728] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 08/03/2020] [Indexed: 12/12/2022] Open
Abstract
As extracellular vesicles, exosomes are released from most cells to perform cell–cell communication. Recent studies have shown that exosomes could be released into tumor microenvironment and blood to promote tumor progression through packaging and transmitting various bioactive molecules, such as cholesterol, proteins, lipids, miRNAs, mRNAs, and long non-coding RNAs (lncRNAs) to distant cells. LncRNAs have emerged as a major class of non-coding transcripts. A lot of LncRNAs have been discovered during the past few years of research on genomics. They have been proven to participate in various biological functions and disease processes through multiple mechanisms. In this review, we analyzed the role of exosome-derived lncRNAs in lung carcinogenesis and metastasis. We also highlight opportunities for the clinical potential of exosomes with specific lncRNAs as biomarkers and therapeutic intervention in lung cancer.
Collapse
Affiliation(s)
- Tao Fan
- Department of Oncology, Renmin Hospital of Wuhan University, Wuhan, China.,Department of Thoracic Surgery, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Nan Sun
- Department of Thoracic Surgery, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Jie He
- Department of Oncology, Renmin Hospital of Wuhan University, Wuhan, China.,Department of Thoracic Surgery, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| |
Collapse
|
62
|
Sharma K, Niraula PM, Troell HA, Adhikari M, Alshehri HA, Alkharouf NW, Lawrence KS, Klink VP. Exocyst components promote an incompatible interaction between Glycine max (soybean) and Heterodera glycines (the soybean cyst nematode). Sci Rep 2020; 10:15003. [PMID: 32929168 PMCID: PMC7490361 DOI: 10.1038/s41598-020-72126-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 08/17/2020] [Indexed: 11/24/2022] Open
Abstract
Vesicle and target membrane fusion involves tethering, docking and fusion. The GTPase SECRETORY4 (SEC4) positions the exocyst complex during vesicle membrane tethering, facilitating docking and fusion. Glycine max (soybean) Sec4 functions in the root during its defense against the parasitic nematode Heterodera glycines as it attempts to develop a multinucleate nurse cell (syncytium) serving to nourish the nematode over its 30-day life cycle. Results indicate that other tethering proteins are also important for defense. The G. max exocyst is encoded by 61 genes: 5 EXOC1 (Sec3), 2 EXOC2 (Sec5), 5 EXOC3 (Sec6), 2 EXOC4 (Sec8), 2 EXOC5 (Sec10) 6 EXOC6 (Sec15), 31 EXOC7 (Exo70) and 8 EXOC8 (Exo84) genes. At least one member of each gene family is expressed within the syncytium during the defense response. Syncytium-expressed exocyst genes function in defense while some are under transcriptional regulation by mitogen-activated protein kinases (MAPKs). The exocyst component EXOC7-H4-1 is not expressed within the syncytium but functions in defense and is under MAPK regulation. The tethering stage of vesicle transport has been demonstrated to play an important role in defense in the G. max-H. glycines pathosystem, with some of the spatially and temporally regulated exocyst components under transcriptional control by MAPKs.
Collapse
Affiliation(s)
- Keshav Sharma
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, 39762, USA
- USDA-ARS Cereal Disease Laboratory, University of Minnesota, 1551 Lindig Street, St. Paul, MN, 55108, USA
| | - Prakash M Niraula
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, 39762, USA
- Department of Plant Pathology and Microbiology, Texas A&M AgriLife Research and Extension Center, Texas A&M University, 2415 E. Hwy. 83, Weslaco, TX, 78596, USA
| | - Hallie A Troell
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, 39762, USA
| | - Mandeep Adhikari
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, 39762, USA
| | - Hamdan Ali Alshehri
- Department of Mathematics and Computer Science, Texas Women's University, Denton, TX, 76204, USA
| | - Nadim W Alkharouf
- Department of Computer and Information Sciences, Towson University, Towson, MD, 21252, USA
| | - Kathy S Lawrence
- Department of Entomology and Plant Pathology, Auburn University, 209 Life Science Building, Auburn, AL, 36849, USA
| | - Vincent P Klink
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, 39762, USA.
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS, 39762, USA.
- Center for Computational Sciences High Performance Computing Collaboratory, Mississippi State University, Mississippi State, MS, 39762, USA.
| |
Collapse
|
63
|
Using proteomics to identify host cell interaction partners for VgrG and IglJ. Sci Rep 2020; 10:14612. [PMID: 32884055 PMCID: PMC7471685 DOI: 10.1038/s41598-020-71641-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/23/2020] [Indexed: 11/17/2022] Open
Abstract
Francisella tularensis is a highly virulent intracellular bacterium and the causative agent of tularemia. The disease is characterized by the suboptimal innate immune response and consequently by the impaired adaptive immunity. The virulence of this pathogen depends on proteins encoded by a genomic island termed the Francisella Pathogenicity Island (FPI). However, the precise biological roles of most of the FPI-encoded proteins remain to be clarified. In this study, we employed stable isotope labeling by amino acids in cell culture (SILAC) in combination with affinity protein purification coupled with liquid chromatography–mass spectrometry to identify potential protein-effector binding pairs for two FPI virulence effectors IglJ and VgrG. Our results may indicate that while the IglJ protein interactions primarily affect mitochondria, the VgrG interactions affect phagosome and/or autophagosome biogenesis via targeting components of the host’s exocyst complex.
Collapse
|
64
|
Niwa M. A cell cycle checkpoint for the endoplasmic reticulum. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118825. [PMID: 32828757 DOI: 10.1016/j.bbamcr.2020.118825] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 08/10/2020] [Accepted: 08/12/2020] [Indexed: 02/07/2023]
Abstract
The generation of new cells is one of the most fundamental aspects of cell biology. Proper regulation of the cell cycle is critical for human health, as underscored by many diseases associated with errors in cell cycle regulation, including both cancer and hereditary diseases. A large body of work has identified regulatory mechanisms and checkpoints that ensure accurate and timely replication and segregation of chromosomal DNA. However, few studies have evaluated the extent to which similar checkpoints exist for the division of cytoplasmic components, including organelles. Such checkpoint mechanisms might be crucial for compartments that cannot be generated de novo, such as the endoplasmic reticulum (ER). In this review, we highlight recent work in the model organism Saccharomyces cerevisiae that led to the discovery of such a checkpoint that ensures that cells inherit functional ER into the daughter cell.
Collapse
Affiliation(s)
- Maho Niwa
- Division of Biological Sciences, Section of Molecular Biology, University of California San Diego, NSB#1, Rm 5328, 9500 Gilman Drive, La Jolla, CA 92093-0377, United States of America.
| |
Collapse
|
65
|
Banik SM, Pedram K, Wisnovsky S, Ahn G, Riley NM, Bertozzi CR. Lysosome-targeting chimaeras for degradation of extracellular proteins. Nature 2020; 584:291-297. [PMID: 32728216 PMCID: PMC7727926 DOI: 10.1038/s41586-020-2545-9] [Citation(s) in RCA: 482] [Impact Index Per Article: 120.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 06/22/2020] [Indexed: 01/30/2023]
Abstract
The majority of therapies that target individual proteins rely on specific activity-modulating interactions with the target protein-for example, enzyme inhibition or ligand blocking. However, several major classes of therapeutically relevant proteins have unknown or inaccessible activity profiles and so cannot be targeted by such strategies. Protein-degradation platforms such as proteolysis-targeting chimaeras (PROTACs)1,2 and others (for example, dTAGs3, Trim-Away4, chaperone-mediated autophagy targeting5 and SNIPERs6) have been developed for proteins that are typically difficult to target; however, these methods involve the manipulation of intracellular protein degradation machinery and are therefore fundamentally limited to proteins that contain cytosolic domains to which ligands can bind and recruit the requisite cellular components. Extracellular and membrane-associated proteins-the products of 40% of all protein-encoding genes7-are key agents in cancer, ageing-related diseases and autoimmune disorders8, and so a general strategy to selectively degrade these proteins has the potential to improve human health. Here we establish the targeted degradation of extracellular and membrane-associated proteins using conjugates that bind both a cell-surface lysosome-shuttling receptor and the extracellular domain of a target protein. These initial lysosome-targeting chimaeras, which we term LYTACs, consist of a small molecule or antibody fused to chemically synthesized glycopeptide ligands that are agonists of the cation-independent mannose-6-phosphate receptor (CI-M6PR). We use LYTACs to develop a CRISPR interference screen that reveals the biochemical pathway for CI-M6PR-mediated cargo internalization in cell lines, and uncover the exocyst complex as a previously unidentified-but essential-component of this pathway. We demonstrate the scope of this platform through the degradation of therapeutically relevant proteins, including apolipoprotein E4, epidermal growth factor receptor, CD71 and programmed death-ligand 1. Our results establish a modular strategy for directing secreted and membrane proteins for lysosomal degradation, with broad implications for biochemical research and for therapeutics.
Collapse
Affiliation(s)
- Steven M Banik
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Kayvon Pedram
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Simon Wisnovsky
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Green Ahn
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | | | - Carolyn R Bertozzi
- Department of Chemistry, Stanford University, Stanford, CA, USA.
- Howard Hughes Medical Institute, Stanford, CA, USA.
| |
Collapse
|
66
|
Gerien KS, Zhang S, Russell AC, Zhu YH, Purde V, Wu JQ. Roles of Mso1 and the SM protein Sec1 in efficient vesicle fusion during fission yeast cytokinesis. Mol Biol Cell 2020; 31:1570-1583. [PMID: 32432970 PMCID: PMC7521796 DOI: 10.1091/mbc.e20-01-0067] [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] [Indexed: 11/11/2022] Open
Abstract
Membrane trafficking during cytokinesis is essential for the delivery of membrane lipids and cargoes to the division site. However, the molecular mechanisms are still incompletely understood. In this study, we demonstrate the importance of uncharacterized fission yeast proteins Mso1 and Sec1 in membrane trafficking during cytokinesis. Fission yeast Mso1 shares homology with budding yeast Mso1 and human Mint1, proteins that interact with Sec1/Munc18 family proteins during vesicle fusion. Sec1/Munc18 proteins and their interactors are important regulators of SNARE complex formation during vesicle fusion. The roles of these proteins in vesicle trafficking during cytokinesis have been barely studied. Here, we show that fission yeast Mso1 is also a Sec1-binding protein and Mso1 and Sec1 localize to the division site interdependently during cytokinesis. The loss of Sec1 localization in mso1Δ cells results in a decrease in vesicle fusion and cytokinesis defects such as slow ring constriction, defective ring disassembly, and delayed plasma membrane closure. We also find that Mso1 and Sec1 may have functions independent of the exocyst tethering complex on the plasma membrane at the division site. Together, Mso1 and Sec1 play essential roles in regulating vesicle fusion and cargo delivery at the division site during cytokinesis.
Collapse
Affiliation(s)
- Kenneth S Gerien
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210.,Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Sha Zhang
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Alexandra C Russell
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Yi-Hua Zhu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Vedud Purde
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210
| | - Jian-Qiu Wu
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210.,Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210
| |
Collapse
|
67
|
Hirano Y, Kinugasa Y, Osakada H, Shindo T, Kubota Y, Shibata S, Haraguchi T, Hiraoka Y. Lem2 and Lnp1 maintain the membrane boundary between the nuclear envelope and endoplasmic reticulum. Commun Biol 2020; 3:276. [PMID: 32483293 PMCID: PMC7264229 DOI: 10.1038/s42003-020-0999-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 05/11/2020] [Indexed: 01/09/2023] Open
Abstract
The nuclear envelope (NE) continues to the endoplasmic reticulum (ER). Proper partitioning of NE and ER is crucial for cellular activity, but the key factors maintaining the boundary between NE and ER remain to be elucidated. Here we show that the conserved membrane proteins Lem2 and Lnp1 cooperatively play a crucial role in maintaining the NE-ER membrane boundary in fission yeast Schizosaccharomyces pombe. Cells lacking both Lem2 and Lnp1 caused severe growth defects associated with aberrant expansion of the NE/ER membranes, abnormal leakage of nuclear proteins, and abnormal formation of vacuolar-like structures in the nucleus. Overexpression of the ER membrane protein Apq12 rescued the growth defect associated with membrane disorder caused by the loss of Lem2 and Lnp1. Genetic analysis showed that Apq12 had overlapping functions with Lnp1. We propose that a membrane protein network with Lem2 and Lnp1 acts as a critical factor to maintain the NE-ER boundary.
Collapse
Affiliation(s)
- Yasuhiro Hirano
- Graduate School of Frontier Biosciences, Osaka University, Suita, 565-0871, Japan.
| | - Yasuha Kinugasa
- Graduate School of Frontier Biosciences, Osaka University, Suita, 565-0871, Japan
- Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, 734-8553, Japan
| | - Hiroko Osakada
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, 651-2492, Japan
| | - Tomoko Shindo
- Electron Microscope Laboratory, Keio University School of Medicine, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Yoshino Kubota
- Graduate School of Frontier Biosciences, Osaka University, Suita, 565-0871, Japan
| | - Shinsuke Shibata
- Electron Microscope Laboratory, Keio University School of Medicine, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Tokuko Haraguchi
- Graduate School of Frontier Biosciences, Osaka University, Suita, 565-0871, Japan
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, 651-2492, Japan
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka University, Suita, 565-0871, Japan.
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, 651-2492, Japan.
| |
Collapse
|
68
|
Marek M, Vincenzetti V, Martin SG. Sterol biosensor reveals LAM-family Ltc1-dependent sterol flow to endosomes upon Arp2/3 inhibition. J Cell Biol 2020; 219:e202001147. [PMID: 32320462 PMCID: PMC7265315 DOI: 10.1083/jcb.202001147] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/03/2020] [Accepted: 03/04/2020] [Indexed: 01/01/2023] Open
Abstract
Sterols are crucial components of biological membranes, which are synthetized in the ER and accumulate in the plasma membrane (PM). Here, by applying a genetically encoded sterol biosensor (D4H), we visualize a sterol flow between PM and endosomes in the fission yeast Schizosaccharomyces pombe. Using time-lapse and correlative light-electron microscopy, we found that inhibition of Arp2/3-dependent F-actin assembly promotes the reversible relocalization of D4H from the PM to internal sterol-rich compartments (STRIC) labeled by synaptobrevin Syb1. Retrograde sterol internalization to STRIC is independent of endocytosis or an intact Golgi, but depends on Ltc1, a LAM/StARkin-family protein localized to ER-PM contact sites. The PM in ltc1Δ cells over-accumulates sterols and upon Arp2/3 inhibition forms extended ER-interacting invaginations, indicating that sterol transfer contributes to PM size homeostasis. Anterograde sterol movement from STRIC is independent of canonical vesicular trafficking but requires Arp2/3, suggesting a novel role for this complex. Thus, transfer routes orthogonal to vesicular trafficking govern the flow of sterols in the cell.
Collapse
Affiliation(s)
| | | | - Sophie G. Martin
- Department of Fundamental Microbiology, University of Lausanne, Switzerland
| |
Collapse
|
69
|
Chai H, Guo J, Zhong Y, Hsu CC, Zou C, Wang P, Zhu JK, Shi H. The plasma-membrane polyamine transporter PUT3 is regulated by the Na + /H + antiporter SOS1 and protein kinase SOS2. THE NEW PHYTOLOGIST 2020; 226:785-797. [PMID: 31901205 DOI: 10.1111/nph.16407] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 12/20/2019] [Indexed: 06/10/2023]
Abstract
In Arabidopsis, the plasma membrane transporter PUT3 is important to maintain the cellular homeostasis of polyamines and plays a role in stabilizing mRNAs of some heat-inducible genes. The plasma membrane Na+ /H+ transporter SOS1 and the protein kinase SOS2 are two salt-tolerance determinants crucial for maintaining intracellular Na+ and K+ homeostasis. Here, we report that PUT3 genetically and physically interacts with SOS1 and SOS2, and these interactions modulate PUT3 transport activity. Overexpression of PUT3 (PUT3OE) results in hypersensitivity of the transgenic plants to polyamine and paraquat. The hypersensitivity of PUT3OE is inhibited by the sos1 and sos2 mutations, which indicates that SOS1 and SOS2 are required for PUT3 transport activity. A protein interaction assay revealed that PUT3 physically interacts with SOS1 and SOS2 in yeast and plant cells. SOS2 phosphorylates PUT3 both in vitro and in vivo. SOS1 and SOS2 synergistically activate the polyamine transport activity of PUT3, and PUT3 also modulates SOS1 activity by activating SOS2 in yeast cells. Overall, our findings suggest that both plasma-membrane proteins PUT3 and SOS1 could form a complex with the protein kinase SOS2 in response to stress conditions and modulate the transport activity of each other through protein interactions and phosphorylation.
Collapse
Affiliation(s)
- Haoxi Chai
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, 201602, China
| | - Jianfei Guo
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, 201602, China
| | - Yingli Zhong
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, China
| | - Chuan-Chih Hsu
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, 201602, China
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Changsong Zou
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, 475001, Henan, China
| | - Pengcheng Wang
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, 201602, China
| | - Jian-Kang Zhu
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, 201602, China
| | - Huazhong Shi
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, 475001, Henan, China
| |
Collapse
|
70
|
Ganesan SJ, Feyder MJ, Chemmama IE, Fang F, Rout MP, Chait BT, Shi Y, Munson M, Sali A. Integrative structure and function of the yeast exocyst complex. Protein Sci 2020; 29:1486-1501. [PMID: 32239688 DOI: 10.1002/pro.3863] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 03/25/2020] [Accepted: 03/27/2020] [Indexed: 12/13/2022]
Abstract
Exocyst is an evolutionarily conserved hetero-octameric tethering complex that plays a variety of roles in membrane trafficking, including exocytosis, endocytosis, autophagy, cell polarization, cytokinesis, pathogen invasion, and metastasis. Exocyst serves as a platform for interactions between the Rab, Rho, and Ral small GTPases, SNARE proteins, and Sec1/Munc18 regulators that coordinate spatial and temporal fidelity of membrane fusion. However, its mechanism is poorly described at the molecular level. Here, we determine the molecular architecture of the yeast exocyst complex by an integrative approach, based on a 3D density map from negative-stain electron microscopy (EM) at ~16 Å resolution, 434 disuccinimidyl suberate and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride cross-links from chemical-crosslinking mass spectrometry, and partial atomic models of the eight subunits. The integrative structure is validated by a previously determined cryo-EM structure, cross-links, and distances from in vivo fluorescence microscopy. Our subunit configuration is consistent with the cryo-EM structure, except for Sec5. While not observed in the cryo-EM map, the integrative model localizes the N-terminal half of Sec3 near the Sec6 subunit. Limited proteolysis experiments suggest that the conformation of Exo70 is dynamic, which may have functional implications for SNARE and membrane interactions. This study illustrates how integrative modeling based on varied low-resolution structural data can inform biologically relevant hypotheses, even in the absence of high-resolution data.
Collapse
Affiliation(s)
- Sai J Ganesan
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA.,Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA
| | - Michael J Feyder
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Ilan E Chemmama
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA.,Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA
| | - Fei Fang
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Michael P Rout
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, New York, USA
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York, USA
| | - Yi Shi
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Mary Munson
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA.,Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA
| |
Collapse
|
71
|
The Role of Secretory Pathways in Candida albicans Pathogenesis. J Fungi (Basel) 2020; 6:jof6010026. [PMID: 32102426 PMCID: PMC7151058 DOI: 10.3390/jof6010026] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 02/19/2020] [Accepted: 02/20/2020] [Indexed: 12/17/2022] Open
Abstract
Candida albicans is a fungus that is a commensal organism and a member of the normal human microbiota. It has the ability to transition into an opportunistic invasive pathogen. Attributes that support pathogenesis include secretion of virulence-associated proteins, hyphal formation, and biofilm formation. These processes are supported by secretion, as defined in the broad context of membrane trafficking. In this review, we examine the role of secretory pathways in Candida virulence, with a focus on the model opportunistic fungal pathogen, Candida albicans.
Collapse
|
72
|
Yang H, Huang K. Dissecting the Vesicular Trafficking Function of IFT Subunits. Front Cell Dev Biol 2020; 7:352. [PMID: 32010685 PMCID: PMC6974671 DOI: 10.3389/fcell.2019.00352] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 12/05/2019] [Indexed: 12/22/2022] Open
Abstract
Intraflagellar transport (IFT) was initially identified as a transport machine with multiple protein subunits, and it is essential for the assembly, disassembly, and maintenance of cilium/flagellum, which serves as the nexus of extracellular-to-intracellular signal integration. To date, in addition to its well-established and indispensable roles in ciliated cells, most IFT subunits have presented more general functions of vesicular trafficking in the non-ciliated cells. Thus, this review aims to summarize the recent progress on the vesicular trafficking functions of the IFT subunits and to highlight the issues that may arise in future research.
Collapse
Affiliation(s)
- Huihui Yang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,Institute of Hydrobiology, University of Chinese Academy of Sciences, Beijing, China
| | - Kaiyao Huang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| |
Collapse
|
73
|
Listeria monocytogenes exploits host exocytosis to promote cell-to-cell spread. Proc Natl Acad Sci U S A 2020; 117:3789-3796. [PMID: 32015134 DOI: 10.1073/pnas.1916676117] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The facultative intracellular pathogen Listeria monocytogenes uses an actin-based motility process to spread within human tissues. Filamentous actin from the human cell forms a tail behind bacteria, propelling microbes through the cytoplasm. Motile bacteria remodel the host plasma membrane into protrusions that are internalized by neighboring cells. A critical unresolved question is whether generation of protrusions by Listeria involves stimulation of host processes apart from actin polymerization. Here we demonstrate that efficient protrusion formation in polarized epithelial cells involves bacterial subversion of host exocytosis. Confocal microscopy imaging indicated that exocytosis is up-regulated in protrusions of Listeria in a manner that depends on the host exocyst complex. Depletion of components of the exocyst complex by RNA interference inhibited the formation of Listeria protrusions and subsequent cell-to-cell spread of bacteria. Additional genetic studies indicated important roles for the exocyst regulators Rab8 and Rab11 in bacterial protrusion formation and spread. The secreted Listeria virulence factor InlC associated with the exocyst component Exo70 and mediated the recruitment of Exo70 to bacterial protrusions. Depletion of exocyst proteins reduced the length of Listeria protrusions, suggesting that the exocyst complex promotes protrusion elongation. Collectively, these results demonstrate that Listeria exploits host exocytosis to stimulate intercellular spread of bacteria.
Collapse
|
74
|
ULK1 phosphorylates Exo70 to suppress breast cancer metastasis. Nat Commun 2020; 11:117. [PMID: 31913283 PMCID: PMC6949295 DOI: 10.1038/s41467-019-13923-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 12/02/2019] [Indexed: 01/17/2023] Open
Abstract
Increased expression of protein kinase ULK1 was reported to negatively correlate with breast cancer metastasis. Here we report that ULK1 suppresses the migration and invasion of human breast cancer cells. The suppressive effect is mediated through direct phosphorylation of Exo70, a key component of the exocyst complex. ULK1 phosphorylation inhibits Exo70 homo-oligomerization as well as its assembly to the exocyst complex, which are needed for cell protrusion formation and matrix metalloproteinases secretion during cell invasion. Reversely, upon growth factor stimulation, Exo70 is phosphorylated by ERK1/2, which in turn suppresses its phosphorylation by ULK1. Together, our study identifies Exo70 as a substrate of ULK1 that inhibits cancer metastasis, and demonstrates that two counteractive regulatory mechanisms are well orchestrated during tumor cell invasion. Elevated expression of ULK1 is known to be inversely correlated with breast cancer metastasis. Here, the authors report Exo70 as a substrate of ULK1 that suppresses cancer metastasis, and show that ERK1/2 mediated phosphorylation of Exo70 leads to opposing effects on tumour cell invasion.
Collapse
|
75
|
Žárský V, Sekereš J, Kubátová Z, Pečenková T, Cvrčková F. Three subfamilies of exocyst EXO70 family subunits in land plants: early divergence and ongoing functional specialization. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:49-62. [PMID: 31647563 DOI: 10.1093/jxb/erz423] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 10/10/2019] [Indexed: 05/27/2023]
Abstract
Localized delivery of plasma membrane and cell wall components is an essential process in all plant cells. The vesicle-tethering complex, the exocyst, an ancient eukaryotic hetero-octameric protein cellular module, assists in targeted delivery of exocytosis vesicles to specific plasma membrane domains. Analyses of Arabidopsis and later other land plant genomes led to the surprising prediction of multiple putative EXO70 exocyst subunit paralogues. All land plant EXO70 exocyst subunits (including those of Bryophytes) form three distinct subfamilies-EXO70.1, EXO70.2, and EXO70.3. Interestingly, while the basal well-conserved EXO70.1 subfamily consists of multiexon genes, the remaining two subfamilies contain mostly single exon genes. Published analyses as well as public transcriptomic and proteomic data clearly indicate that most cell types in plants express and also use several different EXO70 isoforms. Here we sum up recent advances in the characterization of the members of the family of plant EXO70 exocyst subunits and present evidence that members of the EXO70.2 subfamily are often recruited to non-canonical functions in plant membrane trafficking pathways. Engagement of the most evolutionarily dynamic EXO70.2 subfamily of EXO70s in biotic interactions and defence correlates well with massive proliferation and conservation of new protein variants in this subfamily.
Collapse
Affiliation(s)
- Viktor Žárský
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Prague, Czech Republic
- Institute of Experimental Botany, v.v.i., Czech Academy of Sciences, Rozvojová, Prague, Czech Republic
| | - Juraj Sekereš
- Institute of Experimental Botany, v.v.i., Czech Academy of Sciences, Rozvojová, Prague, Czech Republic
| | - Zdeňka Kubátová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Prague, Czech Republic
| | - Tamara Pečenková
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Prague, Czech Republic
- Institute of Experimental Botany, v.v.i., Czech Academy of Sciences, Rozvojová, Prague, Czech Republic
| | - Fatima Cvrčková
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Prague, Czech Republic
| |
Collapse
|
76
|
Wang S, Crisman L, Miller J, Datta I, Gulbranson DR, Tian Y, Yin Q, Yu H, Shen J. Inducible Exoc7/Exo70 knockout reveals a critical role of the exocyst in insulin-regulated GLUT4 exocytosis. J Biol Chem 2019; 294:19988-19996. [PMID: 31740584 PMCID: PMC6937574 DOI: 10.1074/jbc.ra119.010821] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/13/2019] [Indexed: 12/20/2022] Open
Abstract
Insulin promotes glucose uptake by triggering the translocation of glucose transporter type 4 (GLUT4) from intracellular vesicles to the plasma membrane through exocytosis. GLUT4 exocytosis is a vesicle fusion event involving fusion of GLUT4-containing vesicles with the plasma membrane. For GLUT4 vesicle fusion to occur, GLUT4 vesicles must first be tethered to the plasma membrane. A key tethering factor in exocytosis is a heterooctameric protein complex called the exocyst. The role of the exocyst in GLUT4 exocytosis, however, remains incompletely understood. Here we first systematically analyzed data from a genome-scale CRISPR screen in HeLa cells that targeted virtually all known genes in the human genome, including 12 exocyst genes. The screen recovered only a subset of the exocyst genes, including exocyst complex component 7 (Exoc7/Exo70). Other exocyst genes, however, were not isolated in the screen, likely because of functional redundancy. Our findings suggest that selection of an appropriate exocyst gene is critical for genetic studies of exocyst functions. Next we developed an inducible adipocyte genome editing system that enabled Exoc7 gene deletion in adipocytes without interfering with adipocyte differentiation. We observed that insulin-stimulated GLUT4 exocytosis was markedly inhibited in Exoc7 KO adipocytes. Insulin signaling, however, remained intact in these KO cells. These results indicate that the exocyst plays a critical role in insulin-stimulated GLUT4 exocytosis in adipocytes. We propose that the strategy outlined in this work could be instrumental in genetically dissecting other membrane-trafficking pathways in adipocytes.
Collapse
Affiliation(s)
- Shifeng Wang
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
- Department of Chinese Medicine Information Science, Beijing University of Chinese Medicine, Beijing 102488, China
| | - Lauren Crisman
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| | - Jessica Miller
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| | - Ishara Datta
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| | - Daniel R Gulbranson
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| | - Yuan Tian
- Department of Biological Sciences and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306
| | - Qian Yin
- Department of Biological Sciences and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306
| | - Haijia Yu
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Jingshi Shen
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| |
Collapse
|
77
|
Boehm C, Field MC. Evolution of late steps in exocytosis: conservation and specialization of the exocyst complex. Wellcome Open Res 2019; 4:112. [PMID: 31633057 PMCID: PMC6784791 DOI: 10.12688/wellcomeopenres.15142.2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2019] [Indexed: 01/09/2023] Open
Abstract
Background: The eukaryotic endomembrane system most likely arose
via paralogous expansions of genes encoding proteins that specify organelle identity, coat complexes and govern fusion specificity. While the majority of these gene families were established by the time of the last eukaryotic common ancestor (LECA), subsequent evolutionary events has moulded these systems, likely reflecting adaptations retained for increased fitness. As well as sequence evolution, these adaptations include loss of otherwise canonical components, the emergence of lineage-specific proteins and paralog expansion. The exocyst complex is involved in late exocytosis and additional trafficking pathways and a member of the complexes associated with tethering containing helical rods (CATCHR) tethering complex family. CATCHR includes the conserved oligomeric Golgi (COG) complex, homotypic fusion and vacuole protein sorting (HOPS)/class C core vacuole/endosome tethering (CORVET) complexes and several others. The exocyst is integrated into a complex GTPase signalling network in animals, fungi and other lineages. Prompted by discovery of Exo99, a non-canonical subunit in the excavate protist
Trypanosoma brucei, and availability of significantly increased genome sequence data, we re-examined evolution of the exocyst. Methods: We examined the evolution of exocyst components by comparative genomics, phylogenetics and structure prediction. Results: The exocyst composition is highly conserved, but with substantial losses of subunits in the Apicomplexa and expansions in Streptophyta plants, Metazoa and land plants, where for the latter, massive paralog expansion of Exo70 represents an extreme and unique example. Significantly, few taxa retain a partial complex, suggesting that, in general, all subunits are probably required for functionality. Further, the ninth exocyst subunit, Exo99, is specific to the Euglenozoa with a distinct architecture compared to the other subunits and which possibly represents a coat system. Conclusions: These data reveal a remarkable degree of evolutionary flexibility within the exocyst complex, suggesting significant diversity in exocytosis mechanisms.
Collapse
Affiliation(s)
- Cordula Boehm
- School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Mark C Field
- School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK.,Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovic, 37005, Czech Republic
| |
Collapse
|
78
|
Moreiras H, Pereira FJC, Neto MV, Bento-Lopes L, Festas TC, Seabra MC, Barral DC. The exocyst is required for melanin exocytosis from melanocytes and transfer to keratinocytes. Pigment Cell Melanoma Res 2019; 33:366-371. [PMID: 31665827 DOI: 10.1111/pcmr.12840] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 10/07/2019] [Accepted: 10/22/2019] [Indexed: 11/30/2022]
Abstract
Skin pigmentation involves the production of the pigment melanin by melanocytes, in melanosomes and subsequent transfer to keratinocytes. Within keratinocytes, melanin polarizes to the apical perinuclear region to form a protective cap, shielding the DNA from ultraviolet radiation-induced damage. Previously, we found evidence to support the exocytosis by melanocytes of the melanin core, termed melanocore, followed by endo/phagocytosis by keratinocytes as a main form of transfer, with Rab11b playing a key role in the process. Here, we report the requirement for the exocyst tethering complex in melanocore exocytosis and transfer to keratinocytes. We observed that the silencing of the exocyst subunits Sec8 or Exo70 impairs melanocore exocytosis from melanocytes, without affecting melanin synthesis. Moreover, we confirmed by immunoprecipitation that Rab11b interacts with Sec8 in melanocytes. Furthermore, we found that the silencing of Sec8 or Exo70 in melanocytes impairs melanin transfer to keratinocytes. These results support our model as melanocore exocytosis from melanocytes is essential for melanin transfer to keratinocytes and skin pigmentation and suggest that the role of Rab11b in melanocore exocytosis is mediated by the exocyst.
Collapse
Affiliation(s)
- Hugo Moreiras
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Francisco J C Pereira
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Matilde V Neto
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Liliana Bento-Lopes
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Tiago C Festas
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Miguel C Seabra
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Duarte C Barral
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| |
Collapse
|
79
|
Wang J, Wen X, Yang B, Liu D, Li X, Geng F. De novo transcriptome and proteome analysis of Dictyophora indusiata fruiting bodies provides insights into the changes during morphological development. Int J Biol Macromol 2019; 146:875-886. [PMID: 31726131 DOI: 10.1016/j.ijbiomac.2019.09.210] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 09/14/2019] [Accepted: 09/17/2019] [Indexed: 12/01/2022]
Abstract
De novo transcriptome assembly and shotgun proteome analysis of Dictyophora indusiata fruiting bodies were performed. A total of 19,704 unigenes were sequenced, and 4380 proteins were identified. Annotation and functional analysis of the identified proteins were significantly enriched in small molecule synthetic and metabolic processes, protein modification regulation (phosphorylation and ubiquitination), and vesicle transport. Furthermore, quantitative developmental transcriptome analysis was performed between the peach-shaped and mature fruiting bodies, and the results revealed that the metabolism and transport activities were upregulated in the mature stage, while protein translation was downregulated; this regulation is likely the main reason for the significant changes in the nutrients of fruiting bodies. Furthermore, the cell wall stress-dependent MAPK sub-pathway was activated in the mature stage, and fungal cell wall degradation-related genes were upregulated, which could promote reconstruction of the cell wall and might play a key role in the morphological development of D. indusiata fruiting bodies.
Collapse
Affiliation(s)
- Jinqiu Wang
- College of Pharmacy and Biological Engineering, Key Laboratory of Coarse Cereal Processing (Ministry of Agriculture and Rural Affairs), Chengdu University, No. 2025 Chengluo Avenue, Chengdu 610106, PR China
| | - Xuefei Wen
- College of Pharmacy and Biological Engineering, Key Laboratory of Coarse Cereal Processing (Ministry of Agriculture and Rural Affairs), Chengdu University, No. 2025 Chengluo Avenue, Chengdu 610106, PR China
| | - Bowen Yang
- College of Pharmacy and Biological Engineering, Key Laboratory of Coarse Cereal Processing (Ministry of Agriculture and Rural Affairs), Chengdu University, No. 2025 Chengluo Avenue, Chengdu 610106, PR China
| | - Dayu Liu
- College of Pharmacy and Biological Engineering, Key Laboratory of Coarse Cereal Processing (Ministry of Agriculture and Rural Affairs), Chengdu University, No. 2025 Chengluo Avenue, Chengdu 610106, PR China
| | - Xiang Li
- College of Pharmacy and Biological Engineering, Key Laboratory of Coarse Cereal Processing (Ministry of Agriculture and Rural Affairs), Chengdu University, No. 2025 Chengluo Avenue, Chengdu 610106, PR China
| | - Fang Geng
- College of Pharmacy and Biological Engineering, Key Laboratory of Coarse Cereal Processing (Ministry of Agriculture and Rural Affairs), Chengdu University, No. 2025 Chengluo Avenue, Chengdu 610106, PR China.
| |
Collapse
|
80
|
Qian X, Zhou X, Shentu P, Yao Y, Jiao D, Chen Q, Zhou J, Xu Y. Sec3 knockdown inhibits TGF-β induced epithelial-mesenchymal transition through the down-regulation of Akt phosphorylation in A549 cells. Biochem Biophys Res Commun 2019; 519:253-260. [PMID: 31495494 DOI: 10.1016/j.bbrc.2019.08.145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 08/26/2019] [Indexed: 11/17/2022]
Abstract
The exocyst, an evolutionarily conserved octomeric protein complex, has been demonstrated as an essential component for vesicle tethering during cell exocytosis, and participates in various physiological processes in the cell. Although subunits of the exocyst complex have been reported to be involved in the regulation of TGF-β induced cancer cell migration and epithelial-mesenchymal transition (EMT), the potential function of Sec3 in these regulated processes remains unclear. Here, we show that Sec3 knockdown abolishes TGF-β stimulated A549 lung cancer cell migration in vitro and causes defects in the regulated EMT process. In addition, we find that depletion of Sec3 significantly inhibits TGF-β stimulated Akt phosphorylation in A549 cells, whereas the increase of Smad2 phosphorylation is unaffected. Furthermore, replenishment of an RNAi-resistant form of Sec3 is shown to restore the defects of TGF-β induced cell migration, EMT and Akt signaling activation. In summary, our study provides evidence that Sec3 is involved in TGF-β induced cell migration and EMT processes, presumably through the regulation of PI3K/Akt signaling activation in A549 cancer cells.
Collapse
Affiliation(s)
- Xiaohan Qian
- Department of Biomedical Engineering, Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, 310027, China; Department of Respiratory Disease, Thoracic Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, 310003, China
| | - Xiaoxu Zhou
- Department of Biomedical Engineering, Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, 310027, China
| | - Ping Shentu
- Department of Biomedical Engineering, Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, 310027, China
| | - Yuanfa Yao
- Department of Biomedical Engineering, Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, 310027, China
| | - Demin Jiao
- Department of Respiratory Oncology, The 903rd Hospital of PLA, Hangzhou, 310013, China
| | - Qingyong Chen
- Department of Respiratory Oncology, The 903rd Hospital of PLA, Hangzhou, 310013, China
| | - Jianying Zhou
- Department of Respiratory Disease, Thoracic Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, 310003, China
| | - Yingke Xu
- Department of Biomedical Engineering, Key Laboratory of Biomedical Engineering of Ministry of Education, Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, Zhejiang University, Hangzhou, 310027, China; Department of Endocrinology, The Affiliated Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, China.
| |
Collapse
|
81
|
Ramos M, Cortés JCG, Sato M, Rincón SA, Moreno MB, Clemente-Ramos JÁ, Osumi M, Pérez P, Ribas JC. Two S. pombe septation phases differ in ingression rate, septum structure, and response to F-actin loss. J Cell Biol 2019; 218:4171-4194. [PMID: 31597680 PMCID: PMC6891078 DOI: 10.1083/jcb.201808163] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 04/19/2019] [Accepted: 09/10/2019] [Indexed: 12/28/2022] Open
Abstract
Ramos et al. establish that fission yeast septation proceeds in two phases. Initially, the septum is immature and, upon F-actin depolymerization, loses the Bgs1 glucan synthase and fails to ingress. During a second phase, the mature septum can maintain Bgs1 and ingression without F-actin, and ingression becomes Cdc42 and exocyst dependent. In fission yeast, cytokinesis requires a contractile actomyosin ring (CR) coupled to membrane and septum ingression. Septation proceeds in two phases. In anaphase B, the septum ingresses slowly. During telophase, the ingression rate increases, and the CR becomes dispensable. Here, we explore the relationship between the CR and septation by analyzing septum ultrastructure, ingression, and septation proteins in cells lacking F-actin. We show that the two phases of septation correlate with septum maturation and the response of cells to F-actin removal. During the first phase, the septum is immature and, following F-actin removal, rapidly loses the Bgs1 glucan synthase from the membrane edge and fails to ingress. During the second phase, the rapidly ingressing mature septum can maintain a Bgs1 ring and septum ingression without F-actin, but ingression becomes Cdc42 and exocyst dependent. Our results provide new insights into fungal cytokinesis and reveal the dual function of CR as an essential landmark for the concentration of Bgs1 and a contractile structure that maintains septum shape and synthesis.
Collapse
Affiliation(s)
- Mariona Ramos
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Salamanca, Spain
| | - Juan Carlos G Cortés
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Salamanca, Spain
| | - Mamiko Sato
- Laboratory of Electron Microscopy/Bio-imaging Center, Japan Women's University, Bunkyo-ku, Tokyo, Japan
| | - Sergio A Rincón
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Salamanca, Spain
| | - M Belén Moreno
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Salamanca, Spain
| | - José Ángel Clemente-Ramos
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Salamanca, Spain
| | - Masako Osumi
- Laboratory of Electron Microscopy/Bio-imaging Center, Japan Women's University, Bunkyo-ku, Tokyo, Japan.,Integrated Imaging Research Support, Chiyoda-ku, Tokyo, Japan
| | - Pilar Pérez
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Salamanca, Spain
| | - Juan Carlos Ribas
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas/Universidad de Salamanca, Salamanca, Spain
| |
Collapse
|
82
|
Exocyst-mediated apical Wg secretion activates signaling in the Drosophila wing epithelium. PLoS Genet 2019; 15:e1008351. [PMID: 31527874 PMCID: PMC6764796 DOI: 10.1371/journal.pgen.1008351] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 09/27/2019] [Accepted: 08/07/2019] [Indexed: 01/19/2023] Open
Abstract
Wnt proteins are secreted signaling factors that regulate cell fate specification and patterning decisions throughout the animal kingdom. In the Drosophila wing epithelium, Wingless (Wg, the homolog of Wnt1) is secreted from a narrow strip of cells at the dorsal-ventral boundary. However, the route of Wg secretion in polarized epithelial cells remains poorly understood and key proteins involved in this process are still unknown. Here, we performed an in vivo RNAi screen and identified members of the exocyst complex to be required for apical but not basolateral Wg secretion. Specifically blocking the apical Wg secretion leads to reduced downstream signaling. Using an in vivo ‘temporal-rescue’ assay, our results further indicate that apically secreted Wg activates target genes that require high signaling activity. In conclusion, our results demonstrate that the exocyst is required for an apical route of Wg secretion from polarized wing epithelial cells. Regulation of Wnt signaling and the production of Wnt ligands is crucial for proper development and homeostasis, as dysregulation leads to developmental defects and diseases such as cancer. This study addresses the question of how functional Wnt ligands are secreted by epithelial cells. By using the polarized epithelium of the developing Drosophila wing as a model system to study Wnt/Wg secretion, the authors performed a large-scale RNAi screen and identified proteins of the exocyst complex to be required for Wnt signaling. The study shows that exocyst complex preferentially regulates apical secretion of Wg proteins. Taken together, this study identifies routes and regulators for secretion of signaling-active Wnt proteins from polarized epithelial cells.
Collapse
|
83
|
Boehm C, Field MC. Evolution of late steps in exocytosis: conservation, specialization. Wellcome Open Res 2019; 4:112. [DOI: 10.12688/wellcomeopenres.15142.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2019] [Indexed: 11/20/2022] Open
Abstract
Background:The eukaryotic endomembrane system likely aroseviaparalogous expansion of genes encoding proteins specifying organelle identity, coat complexes and government of fusion specificity. While the majority of these gene families were established by the time of the last eukaryotic common ancestor (LECA), subsequent evolutionary events molded these systems, likely reflecting adaptations retained for increased fitness. As well as sequence evolution, these adaptations include loss of otherwise canonical subunits, emergence of lineage-specific proteins and paralog expansion. The exocyst complex is involved in late exocytosis, and possibly additional pathways, and is a member of the complexes associated with tethering containing helical rods (CATCHR) tethering complex family, which includes conserved oligomeric Golgi (COG), homotypic fusion and vacuole protein sorting (HOPS), class C core vacuole/endosome tethering (CORVET) and others. The exocyst is integrated into a complex GTPase signaling network in animals, fungi and other lineages. Prompted by discovery of Exo99, a non-canonical subunit in the excavate protistTrypanosoma brucei,and significantly increased genome sequence data, we examined evolution of the exocyst.Methods:We examined evolution of the exocyst by comparative genomics, phylogenetics and structure prediction.Results:The exocyst is highly conserved, but with substantial losses of subunits in the Apicomplexa and expansions in Streptophyta plants and Metazoa. Significantly, few taxa retain a partial complex, suggesting that, in the main, all subunits are required for functionality. Further, the ninth exocyst subunit Exo99 is specific to the Euglenozoa with a distinct architecture compared to the other subunits and which possibly represents a coat system.Conclusions:These data reveal a remarkable degree of evolutionary flexibility within the exocyst complex, suggesting significant diversity in exocytosis mechanisms.
Collapse
|
84
|
Huang L, Li X, Li Y, Yin X, Li Y, Wu B, Mo H, Liao CJ, Mengiste T, Guo W, Dai M, Zhang C. Endosidin2-14 Targets the Exocyst Complex in Plants and Fungal Pathogens to Inhibit Exocytosis. PLANT PHYSIOLOGY 2019; 180:1756-1770. [PMID: 31072814 PMCID: PMC6752926 DOI: 10.1104/pp.18.01457] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 04/29/2019] [Indexed: 05/29/2023]
Abstract
The evolutionarily conserved octameric exocyst complex tethers secretory vesicles to the site of membrane fusion during exocytosis. The plant exocyst complex functions in cell wall biosynthesis, polarized growth, stress responses, and hormone signaling. In fungal pathogens, the exocyst complex is required for growth, development, and pathogenesis. Endosidin2 (ES2) is known to inhibit exocytosis in plant and mammalian cells by targeting the EXO70 subunit of the exocyst complex. Here we show that an analog of ES2, ES2-14, targets plant and two fungal EXO70s. A lower dosage of ES2-14 than of ES2 is required to inhibit plant growth, plant exocytic trafficking, and fungal growth. ES2-14 treatments inhibit appressorium formation and reduce lesion sizes caused by Magnaporthe oryzae Inhibition of EXO70 by ES2-14 in Botrytis cinerea also reduces its virulence in Arabidopsis (Arabidopsis thaliana). Interestingly, ES2-14 did not affect EXO70 localization or transferrin recycling in mammalian cells. Overall, our results indicate that a minor change in ES2 affects its specificity in targeting EXO70s in different organisms and they demonstrate the potential of using ES2-14 to study the mechanisms of plant and fungal exocytosis and the roles of exocytosis in fungus-plant interactions.
Collapse
Affiliation(s)
- Lei Huang
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
- Purdue Center for Plant Biology, Purdue University, West Lafayette, Indiana 47907
| | - Xiaohui Li
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
- Purdue Center for Plant Biology, Purdue University, West Lafayette, Indiana 47907
| | - Yang Li
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
| | - Xianglin Yin
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907
| | - Yong Li
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907
| | - Bin Wu
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Huaping Mo
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907
| | - Chao-Jan Liao
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
| | - Tesfaye Mengiste
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
| | - Wei Guo
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Mingji Dai
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907
| | - Chunhua Zhang
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
- Purdue Center for Plant Biology, Purdue University, West Lafayette, Indiana 47907
| |
Collapse
|
85
|
Sáez JJ, Diaz J, Ibañez J, Bozo JP, Cabrera Reyes F, Alamo M, Gobert FX, Obino D, Bono MR, Lennon-Duménil AM, Yeaman C, Yuseff MI. The exocyst controls lysosome secretion and antigen extraction at the immune synapse of B cells. J Cell Biol 2019; 218:2247-2264. [PMID: 31197029 PMCID: PMC6605794 DOI: 10.1083/jcb.201811131] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 04/11/2019] [Accepted: 05/22/2019] [Indexed: 02/06/2023] Open
Abstract
BCR engagement enhances microtubule stability, which triggers the mobilization of Exo70 from the centrosome to the immune synapse. BCR engagement activates GEF-H1, which promotes exocyst assembly required for the docking and secretion of lysosomes, facilitating the extraction of surface-tethered antigens. B lymphocytes capture antigens from the surface of presenting cells by forming an immune synapse. Local secretion of lysosomes, which are guided to the synaptic membrane by centrosome repositioning, can facilitate the extraction of immobilized antigens. However, the molecular basis underlying their delivery to precise domains of the plasma membrane remains elusive. Here we show that microtubule stabilization, triggered by engagement of the B cell receptor, acts as a cue to release centrosome-associated Exo70, which is redistributed to the immune synapse. This process is coupled to the recruitment and activation of GEF-H1, which is required for assembly of the exocyst complex, used to promote tethering and fusion of lysosomes at the immune synapse. B cells silenced for GEF-H1 or Exo70 display defective lysosome secretion, which results in impaired antigen extraction and presentation. Thus, centrosome repositioning coupled to changes in microtubule stability orchestrates the spatial-temporal distribution of the exocyst complex to promote polarized lysosome secretion at the immune synapse.
Collapse
Affiliation(s)
- Juan José Sáez
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.,Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Jheimmy Diaz
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jorge Ibañez
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan Pablo Bozo
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Fernanda Cabrera Reyes
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Martina Alamo
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - François-Xavier Gobert
- INSERM U932, Institut Curie, Centre de Recherche, PSL Research University, Paris, Île-de-France, France
| | - Dorian Obino
- INSERM U932, Institut Curie, Centre de Recherche, PSL Research University, Paris, Île-de-France, France
| | - María Rosa Bono
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Ana-María Lennon-Duménil
- INSERM U932, Institut Curie, Centre de Recherche, PSL Research University, Paris, Île-de-France, France
| | - Charles Yeaman
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA
| | - María-Isabel Yuseff
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| |
Collapse
|
86
|
Duan Y, Guo Q, Zhang T, Meng Y, Sun D, Luo G, Liu Y. Cyclin-dependent kinase-mediated phosphorylation of the exocyst subunit Exo84 in late G 1 phase suppresses exocytic secretion and cell growth in yeast. J Biol Chem 2019; 294:11323-11332. [PMID: 31171719 DOI: 10.1074/jbc.ra119.008591] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 05/10/2019] [Indexed: 12/22/2022] Open
Abstract
In eukaryotic cells, the growth rate is strictly regulated for proper progression of the cell cycle. In the budding yeast Saccharomyces cerevisiae, it was previously shown that cell growth dramatically slows down when the cells start budding at the G1/S transition. However, the molecular mechanism for this G1/S-associated growth arrest is unclear. In this study, using exocytic secretion, cyclin-dependent kinase (CDK) assay, immunoprecipitation, and microscopy, we demonstrate that the exocyst subunit Exo84, which is known to be phosphorylated in mitosis, can also be phosphorylated directly by Cdk1 in the late G1 phase. Of note, we found that the Cdk1-mediated Exo84 phosphorylation impairs exocytic secretion in the late G1 phase. Using conditional cdc mutants and phosphodeficient and phosphomimetic exo84 mutants, we further observed that Cdk1-phosphoryated Exo84 inhibits the exocyst complex assembly, exocytic secretion, and cell growth, which may be important for proper execution of the G1/S-phase transition before commitment to a complete cell cycle. Our results suggest that the direct Cdk1-mediated regulation of the exocyst complex critically contributes to the coordination of cell growth and cell cycle progression.
Collapse
Affiliation(s)
- Yuran Duan
- Department of Biochemistry and Molecular Biology, China Medical University, Shenyang 110122, China
| | - Qingguo Guo
- Department of Biochemistry and Molecular Biology, China Medical University, Shenyang 110122, China
| | - Tianrui Zhang
- Department of Biochemistry and Molecular Biology, China Medical University, Shenyang 110122, China
| | - Yuan Meng
- Department of Biochemistry and Molecular Biology, China Medical University, Shenyang 110122, China
| | - Dong Sun
- Institute of Translational Medicine, China Medical University, Shenyang 110122, China
| | - Guangzuo Luo
- Institute of Translational Medicine, China Medical University, Shenyang 110122, China
| | - Ying Liu
- Department of Biochemistry and Molecular Biology, China Medical University, Shenyang 110122, China
| |
Collapse
|
87
|
Live-Cell Structural Biology to Solve Biological Mechanisms: The Case of the Exocyst. Structure 2019; 27:886-892. [DOI: 10.1016/j.str.2019.04.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 04/01/2019] [Accepted: 04/18/2019] [Indexed: 01/24/2023]
|
88
|
Singh S, Kumari R, Chinchwadkar S, Aher A, Matheshwaran S, Manjithaya R. Exocyst Subcomplex Functions in Autophagosome Biogenesis by Regulating Atg9 Trafficking. J Mol Biol 2019; 431:2821-2834. [PMID: 31103773 PMCID: PMC6698439 DOI: 10.1016/j.jmb.2019.04.048] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 04/24/2019] [Accepted: 04/29/2019] [Indexed: 01/16/2023]
Abstract
During autophagy, double-membrane vesicles called autophagosomes capture and degrade the intracellular cargo. The de novo formation of autophagosomes requires several vesicle transport and membrane fusion events which are not completely understood. We studied the involvement of exocyst, an octameric tethering complex, which has a primary function in tethering post-Golgi secretory vesicles to plasma membrane, in autophagy. Our findings indicate that not all subunits of exocyst are involved in selective and general autophagy. We show that in the absence of autophagy specific subunits, autophagy arrest is accompanied by accumulation of incomplete autophagosome-like structures. In these mutants, impaired Atg9 trafficking leads to decreased delivery of membrane to the site of autophagosome biogenesis thereby impeding the elongation and completion of the autophagosomes. The subunits of exocyst, which are dispensable for autophagic function, do not associate with the autophagy specific subcomplex of exocyst.
Collapse
Affiliation(s)
- Sunaina Singh
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, Karnataka, India
| | - Ruchika Kumari
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, Karnataka, India
| | - Sarika Chinchwadkar
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, Karnataka, India
| | - Amol Aher
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, Karnataka, India
| | - Saravanan Matheshwaran
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, 208016, Uttar Pradesh, India
| | - Ravi Manjithaya
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, 560064, Karnataka, India.
| |
Collapse
|
89
|
Liu Y, Zhang T, Sun D, Luo G. The Cdc42 effectors Gic1 and Gic2 regulate polarized post-Golgi secretion. Cell Biosci 2019; 9:33. [PMID: 30988896 PMCID: PMC6449940 DOI: 10.1186/s13578-019-0295-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 03/29/2019] [Indexed: 11/10/2022] Open
Abstract
Background Cell polarity refers to spatial difference in morphology, structure, and function within different parts of a single cell, which plays important roles in a wide range of cellular processes. In eukaryotic cells, the small GTPase Cdc42 and phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) are critical components for cell polarity and required for polarized exocytosis and cell growth. Previous data showed that the GTPase-interacting components, Gic1 and Gic2, control cell polarity through its binding with Cdc42 and PtdIns(4,5)P2 in the plasma membrane in budding yeast. However, whether the Gic proteins regulate polarized exocytosis is unknown. Results In this study, we found that Gic2 co-immunoprecipitates with the exocyst complex, suggesting Gic proteins may be involved in exocytosis. Although we could not show the direct interaction between Gic2 and exocyst, we found gic1Δgic2Δ are synthetically sick with sec3ΔN. We demonstrated that Gic1 and Gic2 are required for polarized exocytosis in a yeast strain harboring the N-terminal domain deletion of Sec3, which is also known as an effector of Cdc42 GTPase. Gic proteins are required for polarized localization of exocyst, growth, and efficient secretion in sec3∆N mutant. In addition, we found that the N-terminal domain of both Gic2 and Sec3 share the similar binding sites of Cdc42. Surprisingly, not all the Sec3/Gic binding deficient cdc42 mutants displayed defects of growth and secretion, indicating that disruption of Cdc42 binding with Gic proteins and Sec3 does not necessarily show secretion defects in cdc42 mutants. Conclusions We conclude that Gic1/2 and Sec3 act in parallel to regulate polarized post-Golgi secretion, but this regulation is not solely controlled by their upstream factor Cdc42. Considering that N-terminal domain of Gic2 and Sec3 can bind to both Cdc42 and PtdIns(4,5)P2, the regulation of Gic protein and Sec3 on polarized secretion may also be controlled by PtdIns(4,5)P2. Further experiments need to be performed to test this hypothesis. Our findings provide important clues for understanding the molecular mechanism of cell polarity establishment in eukaryotic cells. Electronic supplementary material The online version of this article (10.1186/s13578-019-0295-x) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Ying Liu
- 1Department of Biochemistry and Molecular Biology, China Medical University, Shenyang, 110122 China
| | - Tianrui Zhang
- 1Department of Biochemistry and Molecular Biology, China Medical University, Shenyang, 110122 China
| | - Dong Sun
- 2Institute of Translational Medicine, China Medical University, Shenyang, 110122 China
| | - Guangzuo Luo
- 2Institute of Translational Medicine, China Medical University, Shenyang, 110122 China
| |
Collapse
|
90
|
Taylor JM. Editorial overview: Muscle and bone are highly effective communicators. Curr Opin Pharmacol 2019; 34:iv-vii. [PMID: 29221573 DOI: 10.1016/j.coph.2017.11.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Joan M Taylor
- Department of Pathology, University of North Carolina, Chapel Hill, NC 27599, USA; McAllister Heart Institute, University of North Carolina, Chapel Hill, NC 27599, USA.
| |
Collapse
|
91
|
Tay YD, Leda M, Spanos C, Rappsilber J, Goryachev AB, Sawin KE. Fission Yeast NDR/LATS Kinase Orb6 Regulates Exocytosis via Phosphorylation of the Exocyst Complex. Cell Rep 2019; 26:1654-1667.e7. [PMID: 30726745 PMCID: PMC6367570 DOI: 10.1016/j.celrep.2019.01.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 11/03/2018] [Accepted: 01/08/2019] [Indexed: 11/22/2022] Open
Abstract
NDR/LATS kinases regulate multiple aspects of cell polarity and morphogenesis from yeast to mammals. Fission yeast NDR/LATS kinase Orb6 has been proposed to control cell polarity by regulating the Cdc42 guanine nucleotide exchange factor Gef1. Here, we show that Orb6 regulates polarity largely independently of Gef1 and that Orb6 positively regulates exocytosis. Through Orb6 inhibition in vivo and quantitative global phosphoproteomics, we identify Orb6 targets, including proteins involved in membrane trafficking. We confirm Sec3 and Sec5, conserved components of the exocyst complex, as substrates of Orb6 both in vivo and in vitro, and we show that Orb6 kinase activity is important for exocyst localization to cell tips and for exocyst activity during septum dissolution after cytokinesis. We further find that Orb6 phosphorylation of Sec3 contributes to exocyst function in concert with exocyst protein Exo70. We propose that Orb6 contributes to polarized growth by regulating membrane trafficking at multiple levels.
Collapse
Affiliation(s)
- Ye Dee Tay
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Marcin Leda
- SynthSys-Centre for Synthetic and Systems Biology, School of Biological Sciences, University of Edinburgh, CH Waddington Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Christos Spanos
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Juri Rappsilber
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK; Chair of Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, Berlin, 13355, Germany
| | - Andrew B Goryachev
- SynthSys-Centre for Synthetic and Systems Biology, School of Biological Sciences, University of Edinburgh, CH Waddington Building, Max Born Crescent, Edinburgh EH9 3BF, UK.
| | - Kenneth E Sawin
- Wellcome Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK.
| |
Collapse
|
92
|
Ahmed SM, Nishida-Fukuda H, Li Y, McDonald WH, Gradinaru CC, Macara IG. Exocyst dynamics during vesicle tethering and fusion. Nat Commun 2018; 9:5140. [PMID: 30510181 PMCID: PMC6277416 DOI: 10.1038/s41467-018-07467-5] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 11/01/2018] [Indexed: 11/15/2022] Open
Abstract
The exocyst is a conserved octameric complex that tethers exocytic vesicles to the plasma membrane prior to fusion. Exocyst assembly and delivery mechanisms remain unclear, especially in mammalian cells. Here we tagged multiple endogenous exocyst subunits with sfGFP or Halo using Cas9 gene-editing, to create single and double knock-in lines of mammary epithelial cells, and interrogated exocyst dynamics by high-speed imaging and correlation spectroscopy. We discovered that mammalian exocyst is comprised of tetrameric subcomplexes that can associate independently with vesicles and plasma membrane and are in dynamic equilibrium with octamer and monomers. Membrane arrival times are similar for subunits and vesicles, but with a small delay (~80msec) between subcomplexes. Departure of SEC3 occurs prior to fusion, whereas other subunits depart just after fusion. About 9 exocyst complexes are associated per vesicle. These data reveal the mammalian exocyst as a remarkably dynamic two-part complex and provide important insights into assembly/disassembly mechanisms. Exocyst complex tethers vesicles to plasma membranes, but assembly mechanisms remain unclear. Here, the authors use Cas9 gene editing to tag exocyst components in epithelial cells, and find that exocyst subcomplexes are recruited to membranes independently, but are both needed for vesicle fusion.
Collapse
Affiliation(s)
- Syed Mukhtar Ahmed
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37240, USA.
| | - Hisayo Nishida-Fukuda
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37240, USA.,Department of Biochemistry and Molecular Genetics, Ehime University Graduate School of Medicine, Toon, Ehime, 7910295, Japan.,Department of Hepato-Biliary-Pancreatic and Breast Surgery, Ehime University Graduate School of Medicine, Toon, Ehime, 7910295, Japan.,Department of Genome Editing, Institute of Biomedical Sciences, Kansai Medical University, Hirakata, 5731010, Japan
| | - Yuchong Li
- Department of Physics, University of Toronto, Toronto, ON, M5S 1A7, Canada.,Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada
| | - W Hayes McDonald
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37240, USA
| | - Claudiu C Gradinaru
- Department of Physics, University of Toronto, Toronto, ON, M5S 1A7, Canada.,Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada
| | - Ian G Macara
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37240, USA.
| |
Collapse
|
93
|
Walters AD, Amoateng K, Wang R, Chen JH, McDermott G, Larabell CA, Gadal O, Cohen-Fix O. Nuclear envelope expansion in budding yeast is independent of cell growth and does not determine nuclear volume. Mol Biol Cell 2018; 30:131-145. [PMID: 30379612 PMCID: PMC6337908 DOI: 10.1091/mbc.e18-04-0204] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Most cells exhibit a constant ratio between nuclear and cell volume. The mechanism dictating this constant ratio and the nuclear component(s) that scale with cell size are not known. To address this, we examined the consequences to the size and shape of the budding yeast nucleus when cell expansion is inhibited by down-regulating components of the secretory pathway. We find that under conditions where cell size increase is restrained, the nucleus becomes bilobed, with the bulk of the DNA in one lobe and the nucleolus in the other. The formation of bilobed nuclei is dependent on fatty acid and phospholipid synthesis, suggesting that it is associated with nuclear membrane expansion. Bilobed nuclei appeared predominantly after spindle pole body separation, suggesting that nuclear envelope expansion follows cell-cycle cues rather than cell size. Importantly, cells with bilobed nuclei had the same nuclear:cell volume ratio as cells with round nuclei. Therefore, the bilobed nucleus could be a consequence of continued NE expansion as cells traverse the cell cycle without an accompanying increase in nuclear volume due to the inhibition of cell growth. Our data suggest that nuclear volume is not determined by nuclear envelope availability but by one or more nucleoplasmic factors.
Collapse
Affiliation(s)
- Alison D Walters
- Laboratory of Molecular and Cellular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Kwabena Amoateng
- Laboratory of Molecular and Cellular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Renjie Wang
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31000 Toulouse, France
| | - Jian-Hua Chen
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158.,Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Gerry McDermott
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158.,Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Carolyn A Larabell
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158.,Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Olivier Gadal
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31000 Toulouse, France
| | - Orna Cohen-Fix
- Laboratory of Molecular and Cellular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| |
Collapse
|
94
|
Lira M, Arancibia D, Orrego PR, Montenegro-Venegas C, Cruz Y, García J, Leal-Ortiz S, Godoy JA, Gundelfinger ED, Inestrosa NC, Garner CC, Zamorano P, Torres VI. The Exocyst Component Exo70 Modulates Dendrite Arbor Formation, Synapse Density, and Spine Maturation in Primary Hippocampal Neurons. Mol Neurobiol 2018; 56:4620-4638. [DOI: 10.1007/s12035-018-1378-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 10/01/2018] [Indexed: 02/07/2023]
|
95
|
Lepore DM, Martínez-Núñez L, Munson M. Exposing the Elusive Exocyst Structure. Trends Biochem Sci 2018; 43:714-725. [PMID: 30055895 PMCID: PMC6108956 DOI: 10.1016/j.tibs.2018.06.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 06/18/2018] [Accepted: 06/29/2018] [Indexed: 11/18/2022]
Abstract
A major challenge for a molecular understanding of membrane trafficking has been the elucidation of high-resolution structures of large, multisubunit tethering complexes that spatially and temporally control intracellular membrane fusion. Exocyst is a large hetero-octameric protein complex proposed to tether secretory vesicles at the plasma membrane to provide quality control of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-mediated membrane fusion. Breakthroughs in methodologies, including sample preparation, biochemical characterization, fluorescence microscopy, and single-particle cryoelectron microscopy, are providing critical insights into the structure and function of the exocyst. These studies now pose more questions than answers for understanding fundamental functional mechanisms, and they open wide the door for future studies to elucidate interactions with protein and membrane partners, potential conformational changes, and molecular insights into tethering reactions.
Collapse
Affiliation(s)
- Dante M Lepore
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Leonora Martínez-Núñez
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Mary Munson
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA.
| |
Collapse
|
96
|
Outlioua A, Pourcelot M, Arnoult D. The Role of Optineurin in Antiviral Type I Interferon Production. Front Immunol 2018; 9:853. [PMID: 29755463 PMCID: PMC5932347 DOI: 10.3389/fimmu.2018.00853] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/06/2018] [Indexed: 12/14/2022] Open
Abstract
After a viral infection and the stimulation of some pattern-recognition receptors as the toll-like receptor 3 in the endosomes or the RIG-I-like receptors in the cytosol, activation of the IKK-related kinase TBK1 leads to the production of type I interferons (IFNs) after phosphorylation of the transcription factors IRF3 and IRF7. Recent findings indicate an involvement of K63-linked polyubiquitination and of the Golgi-localized protein optineurin (OPTN) in the activation of this crucial kinase involved in innate antiviral immunity. This review summarizes the sensing of viruses and the signaling leading to type I IFN production following TBK1 activation through its ubiquitination and the sensing of ubiquitin chains by OPTN at the Golgi apparatus.
Collapse
Affiliation(s)
- Ahmed Outlioua
- INSERM, UMR_S 1197, Hôpital Paul Brousse, Villejuif, France
- Université Paris-Saclay, Paris, France
- Molecular Genetics and Immunophysiopathology Research Team, Health and Environment Laboratory, Aïn Chock Faculty of Sciences, Hassan II University of Casablanca, Casablanca, Morocco
| | - Marie Pourcelot
- INSERM, UMR_S 1197, Hôpital Paul Brousse, Villejuif, France
- Université Paris-Saclay, Paris, France
- ANSES, INRA, ENVA, UPEC, UMR_1161 Virology, LabEx IBEID, Maisons-Alfort, France
| | - Damien Arnoult
- INSERM, UMR_S 1197, Hôpital Paul Brousse, Villejuif, France
- Université Paris-Saclay, Paris, France
| |
Collapse
|
97
|
Rossi G, Watson K, Kennedy W, Brennwald P. The tomosyn homologue, Sro7, is a direct effector of the Rab GTPase, Sec4, in post-Golgi vesicle tethering. Mol Biol Cell 2018; 29:1476-1486. [PMID: 29668350 PMCID: PMC6014100 DOI: 10.1091/mbc.e18-02-0138] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The tomosyn/Sro7 family is thought to play an important role in cell surface trafficking both as an effector of Rab family GTPases and as a regulator of plasma-membrane SNARE function. Recent work has determined the binding site of GTP-bound Sec4 on Sro7. Here we examine the effect of mutations in Sro7 that block Sec4 binding in determining the role of this interaction in Sro7 function. Using an in vitro vesicle:vesicle tethering assay, we find that most of Sro7's ability to tether vesicles is blocked by mutations that disrupt binding to Sec4-GTP. Similarly, genetic analysis demonstrates that the interaction with Sec4 is important for most of Sro7's functions in vivo. The interaction of Sro7 with Sec4 appears to be particularly important when exocyst function is compromised. This provides strong evidence that Sro7 and the exocyst act as dual effector pathways downstream of Sec4. We also demonstrate that Sro7 tethering requires the presence of Sec4 on both opposing membranes and that homo-oligomerization of Sro7 occurs during vesicle tethering. This suggests a simple model for Sro7 function as a Rab effector in tethering post-Golgi vesicles to the plasma membrane in a pathway parallel to that of the exocyst complex.
Collapse
Affiliation(s)
- Guendalina Rossi
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Kelly Watson
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Wade Kennedy
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Patrick Brennwald
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| |
Collapse
|
98
|
Wersäll A, Williams CM, Brown E, Iannitti T, Williams N, Poole AW. Mouse Platelet Ral GTPases Control P-Selectin Surface Expression, Regulating Platelet-Leukocyte Interaction. Arterioscler Thromb Vasc Biol 2018; 38:787-800. [PMID: 29437579 DOI: 10.1161/atvbaha.117.310294] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 01/25/2018] [Indexed: 01/28/2023]
Abstract
OBJECTIVE RalA and RalB GTPases are important regulators of cell growth, cancer metastasis, and granule secretion. The purpose of this study was to determine the role of Ral GTPases in platelets with the use of platelet-specific gene-knockout mouse models. APPROACH AND RESULTS This study shows that platelets from double knockout mice, in which both GTPases have been deleted, show markedly diminished (≈85% reduction) P-selectin translocation to the surface membrane, suggesting a critical role in α-granule secretion. Surprisingly, however, there were only minor effects on stimulated release of soluble α- and δ-granule content, with no alteration in granule count, morphology, or content. In addition, their expression was not essential for platelet aggregation or thrombus formation. However, absence of surface P-selectin caused a marked reduction (≈70%) in platelet-leukocyte interactions in blood from RalAB double knockout mice, suggesting a role for platelet Rals in platelet-mediated inflammation. CONCLUSIONS Platelet Ral GTPases primarily control P-selectin surface expression, in turn regulating platelet-leukocyte interaction. Ral GTPases could therefore be important novel targets for the selective control of platelet-mediated immune cell recruitment and inflammatory disease.
Collapse
Affiliation(s)
- Andreas Wersäll
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom (A.W., C.M.W., E.B., A.W.P.); and KWS Biotest, Portishead, Bristol, United Kingdom (T.I., N.W.).
| | - Chris M Williams
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom (A.W., C.M.W., E.B., A.W.P.); and KWS Biotest, Portishead, Bristol, United Kingdom (T.I., N.W.)
| | - Edward Brown
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom (A.W., C.M.W., E.B., A.W.P.); and KWS Biotest, Portishead, Bristol, United Kingdom (T.I., N.W.)
| | - Tommaso Iannitti
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom (A.W., C.M.W., E.B., A.W.P.); and KWS Biotest, Portishead, Bristol, United Kingdom (T.I., N.W.)
| | - Neil Williams
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom (A.W., C.M.W., E.B., A.W.P.); and KWS Biotest, Portishead, Bristol, United Kingdom (T.I., N.W.)
| | - Alastair W Poole
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom (A.W., C.M.W., E.B., A.W.P.); and KWS Biotest, Portishead, Bristol, United Kingdom (T.I., N.W.)
| |
Collapse
|
99
|
CSI1, PATROL1, and exocyst complex cooperate in delivery of cellulose synthase complexes to the plasma membrane. Proc Natl Acad Sci U S A 2018; 115:E3578-E3587. [PMID: 29581258 PMCID: PMC5899483 DOI: 10.1073/pnas.1800182115] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Cellulose synthesis occurs exclusively at the plasma membrane by cellulose synthase complexes (CSCs). Therefore, delivery of CSCs to discrete sites at the plasma membrane is critical for cellulose synthesis. Despite their significance, the delivery of CSCs is poorly understood. Here we used proteomics approaches, functional genetics, and live cell imaging to show that the de novo secretion of CSCs is mediated by cooperation among cellulose synthase interactive 1 (CSI1), the plant-specific protein PATROL1, and exocyst complex in Arabidopsis thaliana We propose that CSI1 plays a role in marking the docking site, which allows CSCs-containing vesicles access to the plasma membrane through its interaction with microtubules. PATROL1 assists in exocytosis by its interaction with multiple components, including CSI1, CSCs, and exocyst subunits. Both PATROL1 and the exocyst complex determine the rate of delivery of CSCs to the plasma membrane. By monitoring the exocyst complex, PATROL1, CSI1, and CSCs dynamics in real time, we present a timeline of events for exocytosis of CSCs. Our findings provide unique insights into the evolution of exocytosis in eukaryotes.
Collapse
|
100
|
Chua CEL, Tang BL. Rab 10-a traffic controller in multiple cellular pathways and locations. J Cell Physiol 2018; 233:6483-6494. [PMID: 29377137 DOI: 10.1002/jcp.26503] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 01/24/2018] [Indexed: 12/29/2022]
Abstract
Rab GTPases are key regulators of eukaryotic membrane traffic, and their functions and activities are limited to particular intracellular transport steps and their membrane localization is by and large restricted. Some Rabs do participate in more than one transport steps, but broadly speaking, there is a clear demarcation between exocytic and endocytic Rabs. One Rab protein, Rab10, however, appears to be anomalous in this regard and has a diverse array of functions and subcellular localizations. Rab10 has been implicated in a myriad of activities ranging from polarized exocytosis and endosomal sorting in polarized cells, insulin-dependent Glut4 transport in adipocytes, axonal growth in neurons, and endo-phagocytic processes in macrophages. It's reported subcellular localizations include the endoplasmic reticulum (ER), Golgi/TGN, the endosomes/phagosomes and the primary cilia. In this review, we summarize and discuss the multitude of known roles of Rab10 in cellular membrane transport and the molecular players and mechanisms associated with these roles.
Collapse
Affiliation(s)
- Christelle En Lin Chua
- Singapore Nuclear Research and Safety Initiative, National University of Singapore, Singapore
| | - Bor L Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore
| |
Collapse
|