151
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A Phosphatidylinositol 3-Kinase Effector Alters Phagosomal Maturation to Promote Intracellular Growth of Francisella. Cell Host Microbe 2018; 24:285-295.e8. [PMID: 30057173 DOI: 10.1016/j.chom.2018.07.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 05/11/2018] [Accepted: 06/13/2018] [Indexed: 12/28/2022]
Abstract
Many pathogenic intracellular bacteria manipulate the host phago-endosomal system to establish and maintain a permissive niche. The fate and identity of these intracellular compartments is controlled by phosphoinositide lipids. By mechanisms that have remained undefined, a Francisella pathogenicity island-encoded secretion system allows phagosomal escape and replication of bacteria within host cell cytoplasm. Here we report the discovery that a substrate of this system, outside pathogenicity island A (OpiA), represents a family of wortmannin-resistant bacterial phosphatidylinositol (PI) 3-kinase enzymes with members found in a wide range of intracellular pathogens, including Rickettsia and Legionella spp. We show that OpiA acts on the Francisella-containing phagosome and promotes bacterial escape into the cytoplasm. Furthermore, we demonstrate that the phenotypic consequences of OpiA inactivation are mitigated by endosomal maturation arrest. Our findings suggest that Francisella, and likely other intracellular bacteria, override the finely tuned dynamics of phagosomal PI(3)P in order to promote intracellular survival and pathogenesis.
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152
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Pham HQ, Yoshioka K, Mohri H, Nakata H, Aki S, Ishimaru K, Takuwa N, Takuwa Y. MTMR4, a phosphoinositide-specific 3'-phosphatase, regulates TFEB activity and the endocytic and autophagic pathways. Genes Cells 2018; 23:670-687. [PMID: 29962048 DOI: 10.1111/gtc.12609] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 06/04/2018] [Accepted: 06/05/2018] [Indexed: 02/05/2023]
Abstract
Phosphatidylinositol 3-phosphate (PI(3)P) is the predominant phosphoinositide species in early endosomes and autophagosomes, in which PI(3)P dictates traffic of these organelles. Phosphoinositide levels are tightly regulated by lipid-kinases and -phosphatases; however, a phosphatase that converts PI(3)P back to phosphatidylinositol in the endosomal and autophagosomal compartments is not fully understood. We investigated the subcellular distribution and functions of myotubularin-related protein-4 (MTMR4), which is distinct among other MTMRs in that it possesses a PI(3)P-binding FYVE domain, in lung alveolar epithelium-derived A549 cells. MTMR4 was localized mainly in late endosomes and autophagosomes. MTMR4 knockdown markedly suppressed the motility, fusion, and fission of PI(3)P-enriched structures, resulting in decreases in late endosomes, autophagosomes, and lysosomes, and enlargement of PI(3)P-enriched early and late endosomes. In amino acid- and serum-starved cells, MTMR4 knockdown decreased both autophagosomes and autolysosomes and markedly increased PI(3)P-containing autophagosomes and late endosomes, suggesting that the fusion with lysosomes of autophagosomes and late endosomes might be impaired. Notably, MTMR4 knockdown inhibited the nuclear translocation of starvation stress responsive transcription factor-EB (TFEB) with reduced expression of lysosome-related genes in starved cells. These findings indicate that MTMR4 is essential for the integrity of endocytic and autophagic pathways.
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Affiliation(s)
- Hoa Q Pham
- Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Japan
| | - Kazuaki Yoshioka
- Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Japan
| | - Hiromi Mohri
- Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Japan
| | - Hiroki Nakata
- Department of Histology and Cell Biology, Kanazawa University School of Medicine, Kanazawa, Japan
| | - Sho Aki
- Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Japan
| | - Kazuhiro Ishimaru
- Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Japan
| | - Noriko Takuwa
- Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Japan
- Department of Health and Medical Science, Ishikawa Prefectural Nursing University, Kahoku, Japan
| | - Yoh Takuwa
- Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Japan
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153
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Zheng W, Lin Y, Fang W, Zhao X, Lou Y, Wang G, Zheng H, Liang Q, Abubakar YS, Olsson S, Zhou J, Wang Z. The endosomal recycling of FgSnc1 by FgSnx41-FgSnx4 heterodimer is essential for polarized growth and pathogenicity in Fusarium graminearum. THE NEW PHYTOLOGIST 2018; 219:654-671. [PMID: 29676464 DOI: 10.1111/nph.15178] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 03/19/2018] [Indexed: 05/15/2023]
Abstract
Endosomal sorting machineries regulate the transport of their cargoes among intracellular compartments. However, the molecular nature of such intracellular trafficking processes in pathogenic fungal development and pathogenicity remains unclear. Here, we dissect the roles and molecular mechanisms of two sorting nexin proteins and their cargoes in endosomal recycling in Fusarium graminearum using high-resolution microscopy and high-throughput co-immunoprecipitation strategies. We show that the sorting nexins, FgSnx41 and FgSnx4, interact with each other and assemble into a functionally interdependent heterodimer through their respective BAR domains. Further analyses demonstrate that the dimer localizes to the early endosomal membrane and coordinates endosomal sorting. The small GTPase FgRab5 regulates the correct localization of FgSnx41-FgSnx4 and is consequently required for its trafficking function. The protein FgSnc1 is a cargo of FgSnx41-FgSnx4 and regulates the fusion of secreted vesicles with the fungal growing apex and plasma membrane. In the absence of FgSnx41 or FgSnx4, FgSnc1 is mis-sorted and degraded in the vacuole, and null deletion of either component causes defects in the fungal polarized growth and virulence. Overall, for the first time, our results reveal the mechanism of FgSnc1 endosomal recycling by FgSnx41-FgSnx4 heterodimer which is essential for polarized growth and pathogenicity in F. graminearum.
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Affiliation(s)
- Wenhui Zheng
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Yahong Lin
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Wenqin Fang
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xu Zhao
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Yi Lou
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Guanghui Wang
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Huawei Zheng
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Qifu Liang
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Yakubu Saddeeq Abubakar
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Stefan Olsson
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Jie Zhou
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Zonghua Wang
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
- Institute of Oceanography, Minjiang University, Fuzhou, 350108, China
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154
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Rab11 activity and PtdIns(3)P turnover removes recycling cargo from endosomes. Nat Chem Biol 2018; 14:801-810. [DOI: 10.1038/s41589-018-0086-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 05/10/2018] [Indexed: 12/12/2022]
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155
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Rosselli-Murai LK, Yates JA, Yoshida S, Bourg J, Ho KKY, White M, Prisby J, Tan X, Altemus M, Bao L, Wu ZF, Veatch SL, Swanson JA, Merajver SD, Liu AP. Loss of PTEN promotes formation of signaling-capable clathrin-coated pits. J Cell Sci 2018; 131:jcs.208926. [PMID: 29588397 DOI: 10.1242/jcs.208926] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 03/19/2018] [Indexed: 12/19/2022] Open
Abstract
Defective endocytosis and vesicular trafficking of signaling receptors has recently emerged as a multifaceted hallmark of malignant cells. Clathrin-coated pits (CCPs) display highly heterogeneous dynamics on the plasma membrane where they can take from 20 s to over 1 min to form cytosolic coated vesicles. Despite the large number of cargo molecules that traffic through CCPs, it is not well understood whether signaling receptors activated in cancer, such as epidermal growth factor receptor (EGFR), are regulated through a specific subset of CCPs. The signaling lipid phosphatidylinositol (3,4,5)-trisphosphate [PI(3,4,5)P3], which is dephosphorylated by phosphatase and tensin homolog (PTEN), is a potent tumorigenic signaling lipid. By using total internal reflection fluorescence microscopy and automated tracking and detection of CCPs, we found that EGF-bound EGFR and PTEN are enriched in a distinct subset of short-lived CCPs that correspond with clathrin-dependent EGF-induced signaling. We demonstrated that PTEN plays a role in the regulation of CCP dynamics. Furthermore, increased PI(3,4,5)P3 resulted in higher proportion of short-lived CCPs, an effect that recapitulates PTEN deletion. Altogether, our findings provide evidence for the existence of short-lived 'signaling-capable' CCPs.
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Affiliation(s)
| | - Joel A Yates
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109-5624, USA
| | - Sei Yoshida
- Department of Microbiology and Immunology of Michigan Medical School, University of Michigan, Ann Arbor, MI 48109-5620, USA
| | - Julia Bourg
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Kenneth K Y Ho
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Megan White
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Julia Prisby
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xinyu Tan
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Megan Altemus
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109-5624, USA.,Cancer Biology Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Liwei Bao
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109-5624, USA
| | - Zhi-Fen Wu
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109-5624, USA
| | - Sarah L Veatch
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Joel A Swanson
- Department of Microbiology and Immunology of Michigan Medical School, University of Michigan, Ann Arbor, MI 48109-5620, USA
| | - Sofia D Merajver
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109-5624, USA .,Cell and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Allen P Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA .,Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055, USA.,Cell and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
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156
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Yoshida S, Pacitto R, Inoki K, Swanson J. Macropinocytosis, mTORC1 and cellular growth control. Cell Mol Life Sci 2018; 75:1227-1239. [PMID: 29119228 PMCID: PMC5843684 DOI: 10.1007/s00018-017-2710-y] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 10/31/2017] [Accepted: 11/03/2017] [Indexed: 12/15/2022]
Abstract
The growth and proliferation of metazoan cells are driven by cellular nutrient status and by extracellular growth factors. Growth factor receptors on cell surfaces initiate biochemical signals that increase anabolic metabolism and macropinocytosis, an actin-dependent endocytic process in which relatively large volumes of extracellular solutes and nutrients are internalized and delivered efficiently into lysosomes. Macropinocytosis is prominent in many kinds of cancer cells, and supports the growth of cells transformed by oncogenic K-Ras. Growth factor receptor signaling and the overall metabolic status of the cell are coordinated in the cytoplasm by the mechanistic target-of-rapamycin complex-1 (mTORC1), which positively regulates protein synthesis and negatively regulates molecular salvage pathways such as autophagy. mTORC1 is activated by two distinct Ras-related small GTPases, Rag and Rheb, which associate with lysosomal membranes inside the cell. Rag recruits mTORC1 to the lysosomal surface where Rheb directly binds to and activates mTORC1. Rag is activated by both lysosomal luminal and cytosolic amino acids; Rheb activation requires phosphoinositide 3-kinase, Akt, and the tuberous sclerosis complex-1/2. Signals for activation of Rag and Rheb converge at the lysosomal membrane, and several lines of evidence support the idea that growth factor-dependent endocytosis facilitates amino acid transfer into the lysosome leading to the activation of Rag. This review summarizes evidence that growth factor-stimulated macropinocytosis is essential for amino acid-dependent activation of mTORC1, and that increased solute accumulation by macropinocytosis in transformed cells supports unchecked cell growth.
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Affiliation(s)
- Sei Yoshida
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109-5620, USA
| | - Regina Pacitto
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109-5620, USA
| | - Ken Inoki
- Department of Integrative and Molecular Physiology and Internal Medicine, Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Joel Swanson
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109-5620, USA.
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157
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Záhonová K, Petrželková R, Valach M, Yazaki E, Tikhonenkov DV, Butenko A, Janouškovec J, Hrdá Š, Klimeš V, Burger G, Inagaki Y, Keeling PJ, Hampl V, Flegontov P, Yurchenko V, Eliáš M. Extensive molecular tinkering in the evolution of the membrane attachment mode of the Rheb GTPase. Sci Rep 2018; 8:5239. [PMID: 29588502 PMCID: PMC5869587 DOI: 10.1038/s41598-018-23575-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/15/2018] [Indexed: 02/07/2023] Open
Abstract
Rheb is a conserved and widespread Ras-like GTPase involved in cell growth regulation mediated by the (m)TORC1 kinase complex and implicated in tumourigenesis in humans. Rheb function depends on its association with membranes via prenylated C-terminus, a mechanism shared with many other eukaryotic GTPases. Strikingly, our analysis of a phylogenetically rich sample of Rheb sequences revealed that in multiple lineages this canonical and ancestral membrane attachment mode has been variously altered. The modifications include: (1) accretion to the N-terminus of two different phosphatidylinositol 3-phosphate-binding domains, PX in Cryptista (the fusion being the first proposed synapomorphy of this clade), and FYVE in Euglenozoa and the related undescribed flagellate SRT308; (2) acquisition of lipidic modifications of the N-terminal region, namely myristoylation and/or S-palmitoylation in seven different protist lineages; (3) acquisition of S-palmitoylation in the hypervariable C-terminal region of Rheb in apusomonads, convergently to some other Ras family proteins; (4) replacement of the C-terminal prenylation motif with four transmembrane segments in a novel Rheb paralog in the SAR clade; (5) loss of an evident C-terminal membrane attachment mechanism in Tremellomycetes and some Rheb paralogs of Euglenozoa. Rheb evolution is thus surprisingly dynamic and presents a spectacular example of molecular tinkering.
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Affiliation(s)
- Kristína Záhonová
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Romana Petrželková
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Matus Valach
- Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Canada
| | - Euki Yazaki
- Institute for Biological Sciences, University of Tsukuba, Tsukuba, Japan
| | - Denis V Tikhonenkov
- Laboratory of Microbiology, Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok, Russia
| | - Anzhelika Butenko
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Jan Janouškovec
- Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Štěpánka Hrdá
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Vladimír Klimeš
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Gertraud Burger
- Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Canada
| | - Yuji Inagaki
- Center for Computational Sciences, University of Tsukuba, Tsukuba, Japan
| | - Patrick J Keeling
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Vladimír Hampl
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Pavel Flegontov
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Vyacheslav Yurchenko
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Marek Eliáš
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava, Czech Republic.
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158
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Chen YH, Kratchmarov R, Lin WHW, Rothman NJ, Yen B, Adams WC, Nish SA, Rathmell JC, Reiner SL. Asymmetric PI3K Activity in Lymphocytes Organized by a PI3K-Mediated Polarity Pathway. Cell Rep 2018; 22:860-868. [PMID: 29420173 PMCID: PMC5806629 DOI: 10.1016/j.celrep.2017.12.087] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 11/06/2017] [Accepted: 12/22/2017] [Indexed: 11/18/2022] Open
Abstract
Unequal transmission of nutritive signaling during cell division establishes fate disparity between sibling lymphocytes, but how asymmetric signaling becomes organized is not understood. We show that receptor-associated class I phosphatidylinositol 3-kinase (PI3K) signaling activity, indexed by phosphatidylinositol (3,4,5)-trisphosphate (PIP3) staining, is spatially restricted to the microtubule-organizing center and subsequently to one pole of the mitotic spindle in activated T and B lymphocytes. Asymmetric PI3K activity co-localizes with polarization of antigen receptor components implicated in class I PI3K signaling and with facultative glucose transporters whose trafficking is PI3K dependent and whose abundance marks cells destined for differentiation. Perturbation of class I PI3K activity disrupts asymmetry of upstream antigen receptors and downstream glucose transporter traffic. The roles of PI3K signaling in nutrient utilization, proliferation, and gene expression may have converged with the conserved role of PI3K signaling in cellular symmetry breaking to form a logic for regenerative lymphocyte divisions.
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Affiliation(s)
- Yen-Hua Chen
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Radomir Kratchmarov
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Wen-Hsuan W Lin
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Nyanza J Rothman
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Bonnie Yen
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - William C Adams
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Simone A Nish
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Jeffrey C Rathmell
- Vanderbilt Center for Immunobiology, Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Steven L Reiner
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
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159
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Remodeling of the malaria parasite and host human red cell by vesicle amplification that induces artemisinin resistance. Blood 2018; 131:1234-1247. [PMID: 29363540 DOI: 10.1182/blood-2017-11-814665] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 01/12/2018] [Indexed: 12/25/2022] Open
Abstract
Artemisinin resistance threatens worldwide malaria control and elimination. Elevation of phosphatidylinositol-3-phosphate (PI3P) can induce resistance in blood stages of Plasmodium falciparum The parasite unfolded protein response (UPR) has also been implicated as a proteostatic mechanism that may diminish artemisinin-induced toxic proteopathy. How PI3P acts and its connection to the UPR remain unknown, although both are conferred by mutation in P falciparum Kelch13 (K13), the marker of artemisinin resistance. Here we used cryoimmunoelectron microscopy to show that K13 concentrates at PI3P tubules/vesicles of the parasite's endoplasmic reticulum (ER) in infected red cells. K13 colocalizes and copurifies with the major virulence adhesin PfEMP1. The PfEMP1-K13 proteome is comprehensively enriched in multiple proteostasis systems of protein export, quality control, and folding in the ER and cytoplasm and UPR. Synthetic elevation of PI3P that induces resistance in absence of K13 mutation also yields signatures of proteostasis and clinical resistance. These findings imply a key role for PI3P-vesicle amplification as a mechanism of resistance of infected red cells. As validation, the major resistance mutation K13C580Y quantitatively increased PI3P tubules/vesicles, exporting them throughout the parasite and the red cell. Chemical inhibitors and fluorescence microscopy showed that alterations in PfEMP1 export to the red cell and cytoadherence of infected cells to a host endothelial receptor are features of multiple K13 mutants. Together these data suggest that amplified PI3P vesicles disseminate widespread proteostatic capacity that may neutralize artemisinins toxic proteopathy and implicate a role for the host red cell in artemisinin resistance. The mechanistic insights generated will have an impact on malaria drug development.
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160
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Wallroth A, Haucke V. Phosphoinositide conversion in endocytosis and the endolysosomal system. J Biol Chem 2017; 293:1526-1535. [PMID: 29282290 DOI: 10.1074/jbc.r117.000629] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Phosphoinositides (PIs) are phospholipids that perform crucial cell functions, ranging from cell migration and signaling to membrane trafficking, by serving as signposts of compartmental membrane identity. Although phosphatidylinositol 4,5-bisphosphate, 3-phosphate, and 3,5-bisphosphate are commonly considered as hallmarks of the plasma membrane, endosomes, and lysosomes, these compartments contain other functionally important PIs. Here, we review the roles of PIs in different compartments of the endolysosomal system in mammalian cells and discuss the mechanisms that spatiotemporally control PI conversion in endocytosis and endolysosomal membrane dynamics during endosome maturation and sorting. As defective PI conversion underlies human genetic diseases, including inherited myopathies, neurological disorders, and cancer, PI-converting enzymes represent potential targets for drug-based therapies.
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Affiliation(s)
- Alexander Wallroth
- From the Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse 10, 13125 Berlin and
| | - Volker Haucke
- From the Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse 10, 13125 Berlin and .,the Faculty of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
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161
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Gulluni F, Martini M, Hirsch E. Cytokinetic Abscission: Phosphoinositides and ESCRTs Direct the Final Cut. J Cell Biochem 2017; 118:3561-3568. [PMID: 28419521 DOI: 10.1002/jcb.26066] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 04/14/2017] [Indexed: 01/23/2023]
Abstract
Cytokinetic abscission involves the fine and regulated recruitment of membrane remodeling proteins that participate in the abscission of the intracellular bridge that connects the two dividing cells. This essential process is mediated by the concomitant activity of the endosomal sorting complex required for transport (ESCRT) and the vesicular trafficking directed to the midbody. Phosphoinositides (PtdIns), produced at plasma membrane, and endosomes, act as molecular intermediates by recruiting effector proteins involved in multiple cellular processes, such as intracellular signaling, endo- and exo-cytosis, and membrane remodeling events. Emerging evidences suggest that PtdIns have an active role in recruiting key elements that control the stability and the remodeling of the cytoskeleton from the furrow ingression to the abscission, at the end of cytokinesis. Accordingly, a possible concomitant and coordinated activity between PtdIns production and ESCRT machinery assembly could also exist and recent findings are pointing the attention on poorly understood ESCRT subunits potentially able to associate with PtdIns rich membranes. Although further studies are required to link PtdIns to ESCRT machinery during abscission, this might represent a promising field of study. J. Cell. Biochem. 118: 3561-3568, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Federico Gulluni
- Department of Molecular Biotechnology and Health Sciences, University of Turin, Turin, Italy
| | - Miriam Martini
- Department of Molecular Biotechnology and Health Sciences, University of Turin, Turin, Italy
| | - Emilio Hirsch
- Department of Molecular Biotechnology and Health Sciences, University of Turin, Turin, Italy
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162
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Strategies for the etiological therapy of cystic fibrosis. Cell Death Differ 2017; 24:1825-1844. [PMID: 28937684 PMCID: PMC5635223 DOI: 10.1038/cdd.2017.126] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 06/22/2017] [Accepted: 06/23/2017] [Indexed: 12/14/2022] Open
Abstract
Etiological therapies aim at repairing the underlying cause of cystic fibrosis (CF), which is the functional defect of the cystic fibrosis transmembrane conductance regulator (CFTR) protein owing to mutations in the CFTR gene. Among these, the F508del CFTR mutation accounts for more than two thirds of CF cases worldwide. Two somehow antinomic schools of thought conceive CFTR repair in a different manner. According to one vision, drugs should directly target the mutated CFTR protein to increase its plasma membrane expression (correctors) or improve its ion transport function (potentiators). An alternative strategy consists in modulating the cellular environment and proteostasis networks in which the mutated CFTR protein is synthesized, traffics to its final destination, the plasma membrane, and is turned over. We will analyze distinctive advantages and drawbacks of these strategies in terms of their scientific and clinical dimensions, and we will propose a global strategy for CF research and development based on a reconciliatory approach. Moreover, we will discuss the utility of preclinical biomarkers that may guide the personalized, patient-specific implementation of CF therapies.
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163
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Shen Y, Wen Z, Li Y, Matteson EL, Hong J, Goronzy JJ, Weyand CM. Metabolic control of the scaffold protein TKS5 in tissue-invasive, proinflammatory T cells. Nat Immunol 2017; 18:1025-1034. [PMID: 28737753 PMCID: PMC5568495 DOI: 10.1038/ni.3808] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 06/28/2017] [Indexed: 12/13/2022]
Abstract
Pathogenic T cells in individuals with rheumatoid arthritis (RA) infiltrate non-lymphoid tissue sites, maneuver through extracellular matrix and form lasting inflammatory microstructures. Here we found that RA T cells abundantly express the podosome scaffolding protein TKS5, which enables them to form tissue-invasive membrane structures. TKS5 overexpression was regulated by the intracellular metabolic environment of RA T cells-specifically, by reduced glycolytic flux that led to deficiencies in ATP and pyruvate. ATPlopyruvatelo conditions triggered fatty acid biosynthesis and the formation of cytoplasmic lipid droplets. Restoration of pyruvate production or inhibition of fatty acid synthesis corrected the tissue-invasiveness of RA T cells in vivo and reversed their proarthritogenic behavior. Thus, metabolic control of T cell locomotion provides new opportunities to interfere with T cell invasion into specific tissue sites.
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Affiliation(s)
- Yi Shen
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Zhenke Wen
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yinyin Li
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Eric L. Matteson
- Division of Rheumatology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Jison Hong
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jörg J. Goronzy
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Cornelia M. Weyand
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
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164
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Nascimbeni AC, Codogno P, Morel E. Local detection of PtdIns3P at autophagosome biogenesis membrane platforms. Autophagy 2017; 13:1602-1612. [PMID: 28813193 DOI: 10.1080/15548627.2017.1341465] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Phosphatidylinositol 3-phosphate (PtdIns3P) is a key player of membrane trafficking regulation, mostly synthesized by the PIK3C3 lipid kinase. The presence of PtdIns3P on endosomes has been demonstrated; however, the role and dynamics of the pool of PtdIns3P dedicated to macroautophagy/autophagy remains elusive. Here we addressed this question by studying the mobilization of PtdIns3P in time and space during autophagosome biogenesis. We compared different dyes known to specifically detect PtdIns3P by fluorescence microscopy analysis, based on PtdIns3P-binding FYVE and PX domains, and show that these transfected dyes induce defects in endosomal dynamics as well as artificial and sustained autophagosome formation. In contrast, indirect use of recombinant FYVE enabled us to track and discriminate endosomal and autophagosomal pools of PtdIns3P. We used this method to analyze localization and dynamics of PtdIns3P subdomains on the endoplasmic reticulum, at sites of pre-autophagosome associated protein recruitment such as the PtdIns3P-binding ZFYVE1/DFCP1 and WIPI2 autophagy regulators. This approach thus revealed the presence of a specific pool of PtdIns3P at the site where autophagosome assembly is initiated.
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Affiliation(s)
- Anna Chiara Nascimbeni
- a Cell Biology Department , Institut Necker-Enfants Malades (INEM) , INSERM U1151-CNRS UMR 8253, Paris , France.,b Université Paris Descartes-Sorbonne Paris Cité , Paris , France
| | - Patrice Codogno
- a Cell Biology Department , Institut Necker-Enfants Malades (INEM) , INSERM U1151-CNRS UMR 8253, Paris , France.,b Université Paris Descartes-Sorbonne Paris Cité , Paris , France
| | - Etienne Morel
- a Cell Biology Department , Institut Necker-Enfants Malades (INEM) , INSERM U1151-CNRS UMR 8253, Paris , France.,b Université Paris Descartes-Sorbonne Paris Cité , Paris , France
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165
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Lymphocyte Fate and Metabolism: A Clonal Balancing Act. Trends Cell Biol 2017; 27:946-954. [PMID: 28818395 DOI: 10.1016/j.tcb.2017.07.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 07/12/2017] [Accepted: 07/24/2017] [Indexed: 01/16/2023]
Abstract
Activated lymphocytes perform a clonal balancing act, yielding a daughter cell that differentiates owing to intense PI3K signaling, alongside a self-renewing sibling cell with blunted anabolic signaling. Divergent cellular anabolism versus catabolism is emerging as a feature of several developmental and regenerative paradigms. Metabolism can dictate cell fate, in part, because lineage-specific regulators are embedded in the circuitry of conserved metabolic switches. Unequal transmission of PI3K signaling during regenerative divisions is reminiscent of compartmentalized PI3K activity during directed motility or polarized information flow in non-dividing cells. The diverse roles of PI3K pathways in membrane traffic, cell polarity, metabolism, and gene expression may have converged to instruct sibling cell feast and famine, thereby enabling clonal differentiation alongside self-renewal.
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166
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Reidick C, Boutouja F, Platta HW. The class III phosphatidylinositol 3-kinase Vps34 in Saccharomyces cerevisiae. Biol Chem 2017; 398:677-685. [PMID: 27935849 DOI: 10.1515/hsz-2016-0288] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 11/14/2016] [Indexed: 12/23/2022]
Abstract
The class III phosphatidylinositol 3-kinase Vps34 (vacuolar protein sorting 34) catalyzes for the formation of the signaling lipid phosphatidylinositol-3-phopsphate, which is a central factor in the regulation of autophagy, endocytic trafficking and vesicular transport. In this article, we discuss the functional role of the lipid kinase Vps34 in Saccharomyces cerevisiae.
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Affiliation(s)
- Christina Reidick
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, D-44801 Bochum
| | - Fahd Boutouja
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, D-44801 Bochum
| | - Harald W Platta
- Biochemie Intrazellulärer Transportprozesse, Ruhr-Universität Bochum, D-44801 Bochum
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167
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Brandizzi F. Transport from the endoplasmic reticulum to the Golgi in plants: Where are we now? Semin Cell Dev Biol 2017; 80:94-105. [PMID: 28688928 DOI: 10.1016/j.semcdb.2017.06.024] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/11/2017] [Accepted: 06/27/2017] [Indexed: 11/26/2022]
Abstract
The biogenesis of about one third of the cellular proteome is initiated in the endoplasmic reticulum (ER), which exports proteins to the Golgi apparatus for sorting to their final destination. Notwithstanding the close proximity of the ER with other secretory membranes (e.g., endosomes, plasma membrane), the ER is also important for the homeostasis of non-secretory organelles such as mitochondria, peroxisomes, and chloroplasts. While how the plant ER interacts with most of the non-secretory membranes is largely unknown, the knowledge on the mechanisms for ER-to-Golgi transport is relatively more advanced. Indeed, over the last fifteen years or so, a large number of exciting results have contributed to draw parallels with non-plant species but also to highlight the complexity of the plant ER-Golgi interface, which bears unique features. This review reports and discusses results on plant ER-to-Golgi traffic, focusing mainly on research on COPII-mediated transport in the model species Arabidopsis thaliana.
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Affiliation(s)
- Federica Brandizzi
- MSU-DOE Plant Research Lab and Plant Biology Department, Michigan State University, East Lansing, MI 48824, USA; Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA; Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824, USA.
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168
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Nascimbeni AC, Giordano F, Dupont N, Grasso D, Vaccaro MI, Codogno P, Morel E. ER-plasma membrane contact sites contribute to autophagosome biogenesis by regulation of local PI3P synthesis. EMBO J 2017; 36:2018-2033. [PMID: 28550152 DOI: 10.15252/embj.201797006] [Citation(s) in RCA: 149] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 04/27/2017] [Accepted: 04/28/2017] [Indexed: 12/21/2022] Open
Abstract
The double-membrane-bound autophagosome is formed by the closure of a structure called the phagophore, origin of which is still unclear. The endoplasmic reticulum (ER) is clearly implicated in autophagosome biogenesis due to the presence of the omegasome subdomain positive for DFCP1, a phosphatidyl-inositol-3-phosphate (PI3P) binding protein. Contribution of other membrane sources, like the plasma membrane (PM), is still difficult to integrate in a global picture. Here we show that ER-plasma membrane contact sites are mobilized for autophagosome biogenesis, by direct implication of the tethering extended synaptotagmins (E-Syts) proteins. Imaging data revealed that early autophagic markers are recruited to E-Syt-containing domains during autophagy and that inhibition of E-Syts expression leads to a reduction in autophagosome biogenesis. Furthermore, we demonstrate that E-Syts are essential for autophagy-associated PI3P synthesis at the cortical ER membrane via the recruitment of VMP1, the stabilizing ER partner of the PI3KC3 complex. These results highlight the contribution of ER-plasma membrane tethers to autophagosome biogenesis regulation and support the importance of membrane contact sites in autophagy.
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Affiliation(s)
- Anna Chiara Nascimbeni
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Paris, France.,Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Francesca Giordano
- Institut Jacques Monod, CNRS UMR 7592, Paris, France.,Université Paris Diderot-Sorbonne Paris Cité, Paris, France
| | - Nicolas Dupont
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Paris, France.,Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Daniel Grasso
- Department of Pathophysiology, Institute of Biochemistry and Molecular Medicine, National Council for Scientific and Technological Research, School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina
| | - Maria I Vaccaro
- Department of Pathophysiology, Institute of Biochemistry and Molecular Medicine, National Council for Scientific and Technological Research, School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina
| | - Patrice Codogno
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Paris, France.,Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Etienne Morel
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Paris, France .,Université Paris Descartes-Sorbonne Paris Cité, Paris, France
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169
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Carpaneto A, Boccaccio A, Lagostena L, Di Zanni E, Scholz-Starke J. The signaling lipid phosphatidylinositol-3,5-bisphosphate targets plant CLC-a anion/H + exchange activity. EMBO Rep 2017; 18:1100-1107. [PMID: 28536248 DOI: 10.15252/embr.201643814] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 04/20/2017] [Accepted: 04/21/2017] [Indexed: 12/21/2022] Open
Abstract
Phosphatidylinositol-3,5-bisphosphate (PI(3,5)P2) is a low-abundance signaling lipid associated with endo-lysosomal and vacuolar membranes in eukaryotic cells. Recent studies on Arabidopsis indicated a critical role of PI(3,5)P2 in vacuolar acidification and morphology during ABA-induced stomatal closure, but the molecular targets in plant cells remained unknown. By using patch-clamp recordings on Arabidopsis vacuoles, we show here that PI(3,5)P2 does not affect the activity of vacuolar H+-pyrophosphatase or vacuolar H+-ATPase. Instead, PI(3,5)P2 at low nanomolar concentrations inhibited an inwardly rectifying conductance, which appeared upon vacuolar acidification elicited by prolonged H+ pumping activity. We provide evidence that this novel conductance is mediated by chloride channel a (CLC-a), a member of the anion/H+ exchanger family formerly implicated in stomatal movements in Arabidopsis H+-dependent currents were absent in clc-a knock-out vacuoles, and canonical CLC-a-dependent nitrate/H+ antiport was inhibited by low concentrations of PI(3,5)P2 Finally, using the pH indicator probe BCECF, we show that CLC-a inhibition contributes to vacuolar acidification. These data provide a mechanistic explanation for the essential role of PI(3,5)P2 and advance our knowledge about the regulation of vacuolar ion transport.
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Affiliation(s)
- Armando Carpaneto
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Anna Boccaccio
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Laura Lagostena
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Eleonora Di Zanni
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, Genova, Italy
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170
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Vanhauwaert R, Kuenen S, Masius R, Bademosi A, Manetsberger J, Schoovaerts N, Bounti L, Gontcharenko S, Swerts J, Vilain S, Picillo M, Barone P, Munshi ST, de Vrij FM, Kushner SA, Gounko NV, Mandemakers W, Bonifati V, Meunier FA, Soukup SF, Verstreken P. The SAC1 domain in synaptojanin is required for autophagosome maturation at presynaptic terminals. EMBO J 2017; 36:1392-1411. [PMID: 28331029 DOI: 10.15252/embj.201695773] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 02/25/2017] [Accepted: 03/01/2017] [Indexed: 11/09/2022] Open
Abstract
Presynaptic terminals are metabolically active and accrue damage through continuous vesicle cycling. How synapses locally regulate protein homeostasis is poorly understood. We show that the presynaptic lipid phosphatase synaptojanin is required for macroautophagy, and this role is inhibited by the Parkinson's disease mutation R258Q. Synaptojanin drives synaptic endocytosis by dephosphorylating PI(4,5)P2, but this function appears normal in SynaptojaninRQ knock-in flies. Instead, R258Q affects the synaptojanin SAC1 domain that dephosphorylates PI(3)P and PI(3,5)P2, two lipids found in autophagosomal membranes. Using advanced imaging, we show that SynaptojaninRQ mutants accumulate the PI(3)P/PI(3,5)P2-binding protein Atg18a on nascent synaptic autophagosomes, blocking autophagosome maturation at fly synapses and in neurites of human patient induced pluripotent stem cell-derived neurons. Additionally, we observe neurodegeneration, including dopaminergic neuron loss, in SynaptojaninRQ flies. Thus, synaptojanin is essential for macroautophagy within presynaptic terminals, coupling protein turnover with synaptic vesicle cycling and linking presynaptic-specific autophagy defects to Parkinson's disease.
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Affiliation(s)
- Roeland Vanhauwaert
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Sabine Kuenen
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Roy Masius
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Adekunle Bademosi
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Qld, Australia
| | - Julia Manetsberger
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Nils Schoovaerts
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Laura Bounti
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Serguei Gontcharenko
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Jef Swerts
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Sven Vilain
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Marina Picillo
- Department of Medicine and Surgery, Center for Neurodegenerative Diseases (CEMAND), University of Salerno, Salerno, Italy
| | - Paolo Barone
- Department of Medicine and Surgery, Center for Neurodegenerative Diseases (CEMAND), University of Salerno, Salerno, Italy
| | | | - Femke Ms de Vrij
- Department of Psychiatry, Erasmus MC, Rotterdam, The Netherlands
| | - Steven A Kushner
- Department of Psychiatry, Erasmus MC, Rotterdam, The Netherlands
| | - Natalia V Gounko
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium.,Electron Microscopy Platform, VIB Bio-Imaging Core, Leuven, Belgium
| | - Wim Mandemakers
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Vincenzo Bonifati
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Frederic A Meunier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Qld, Australia
| | - Sandra-Fausia Soukup
- VIB Center for Brain & Disease Research, Leuven, Belgium .,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
| | - Patrik Verstreken
- VIB Center for Brain & Disease Research, Leuven, Belgium .,Department of Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), KU Leuven, Leuven, Belgium
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171
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Nascimbeni AC, Codogno P, Morel E. Phosphatidylinositol-3-phosphate in the regulation of autophagy membrane dynamics. FEBS J 2017; 284:1267-1278. [PMID: 27973739 DOI: 10.1111/febs.13987] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 11/15/2016] [Accepted: 12/07/2016] [Indexed: 12/30/2022]
Abstract
Phosphatidylinositol-3-phosphate (PI3P) is a key player in membrane dynamics and trafficking regulation. Most PI3P is associated with endosomal membranes and with the autophagosome preassembly machinery, presumably at the endoplasmic reticulum. The enzyme responsible for most PI3P synthesis, VPS34 and proteins such as Beclin1 and ATG14L that regulate PI3P levels are positive modulators of autophagy initiation. It had been assumed that a local PI3P pool was present at autophagosomes and preautophagosomal structures, such as the omegasome and the phagophore. This was recently confirmed by the demonstration that PI3P-binding proteins participate in the complex sequence of signalling that results in autophagosome assembly and activity. Here we summarize the historical discoveries of PI3P lipid kinase involvement in autophagy, and we discuss the proposed role of PI3P during autophagy, notably during the autophagosome biogenesis sequence.
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Affiliation(s)
- Anna Chiara Nascimbeni
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Paris, France.,Université Paris Descartes-Sorbonne Paris Cité, France
| | - Patrice Codogno
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Paris, France.,Université Paris Descartes-Sorbonne Paris Cité, France
| | - Etienne Morel
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR 8253, Paris, France.,Université Paris Descartes-Sorbonne Paris Cité, France
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172
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Chen PH, Yao H, Huang LJS. Cytokine Receptor Endocytosis: New Kinase Activity-Dependent and -Independent Roles of PI3K. Front Endocrinol (Lausanne) 2017; 8:78. [PMID: 28507533 PMCID: PMC5410625 DOI: 10.3389/fendo.2017.00078] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 03/30/2017] [Indexed: 12/14/2022] Open
Abstract
Type I and II cytokine receptors are cell surface sensors that bind cytokines in the extracellular environment and initiate intracellular signaling to control processes such as hematopoiesis, immune function, and cellular growth and development. One key mechanism that regulates signaling from cytokine receptors is through receptor endocytosis. In this mini-review, we describe recent advances in endocytic regulations of cytokine receptors, focusing on new paradigms by which PI3K controls receptor endocytosis through both kinase activity-dependent and -independent mechanisms. These advances underscore the notion that the p85 regulatory subunit of PI3K has functions beyond regulating PI3K kinase activity, and that PI3K plays both positive and negative roles in receptor signaling. On the one hand, the PI3K/Akt pathway controls various aspects downstream of cytokine receptors. On the other hand, it stimulates receptor endocytosis and downregulation, thus contributing to signaling attenuation.
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Affiliation(s)
- Ping-hung Chen
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Huiyu Yao
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Lily Jun-shen Huang
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- *Correspondence: Lily Jun-shen Huang,
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173
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Papadopoulos T, Rhee HJ, Subramanian D, Paraskevopoulou F, Mueller R, Schultz C, Brose N, Rhee JS, Betz H. Endosomal Phosphatidylinositol 3-Phosphate Promotes Gephyrin Clustering and GABAergic Neurotransmission at Inhibitory Postsynapses. J Biol Chem 2016; 292:1160-1177. [PMID: 27941024 DOI: 10.1074/jbc.m116.771592] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Indexed: 11/06/2022] Open
Abstract
The formation of neuronal synapses and the dynamic regulation of their efficacy depend on the proper assembly of the postsynaptic neurotransmitter receptor apparatus. Receptor recruitment to inhibitory GABAergic postsynapses requires the scaffold protein gephyrin and the guanine nucleotide exchange factor collybistin (Cb). In vitro, the pleckstrin homology domain of Cb binds phosphoinositides, specifically phosphatidylinositol 3-phosphate (PI3P). However, whether PI3P is required for inhibitory postsynapse formation is currently unknown. Here, we investigated the role of PI3P at developing GABAergic postsynapses by using a membrane-permeant PI3P derivative, time-lapse confocal imaging, electrophysiology, as well as knockdown and overexpression of PI3P-metabolizing enzymes. Our results provide the first in cellula evidence that PI3P located at early/sorting endosomes regulates the postsynaptic clustering of gephyrin and GABAA receptors and the strength of inhibitory, but not excitatory, postsynapses in cultured hippocampal neurons. In human embryonic kidney 293 cells, stimulation of gephyrin cluster formation by PI3P depends on Cb. We therefore conclude that the endosomal pool of PI3P, generated by the class III phosphatidylinositol 3-kinase, is important for the Cb-mediated recruitment of gephyrin and GABAA receptors to developing inhibitory postsynapses and thus the formation of postsynaptic membrane specializations.
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Affiliation(s)
- Theofilos Papadopoulos
- From the Department of Molecular Biology, Center of Biochemistry and Molecular Cell Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany,
| | - Hong Jun Rhee
- the Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Hermann-Rein-Strasse 3, 37075 Göttingen, Germany
| | - Devaraj Subramanian
- the European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Foteini Paraskevopoulou
- From the Department of Molecular Biology, Center of Biochemistry and Molecular Cell Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Rainer Mueller
- the European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Carsten Schultz
- the European Molecular Biology Laboratory (EMBL), Cell Biology and Biophysics Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany.,the Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon 97239-3098
| | - Nils Brose
- the Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Hermann-Rein-Strasse 3, 37075 Göttingen, Germany
| | - Jeong-Seop Rhee
- the Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Hermann-Rein-Strasse 3, 37075 Göttingen, Germany
| | - Heinrich Betz
- the Department of Neurochemistry, Max Planck Institute for Brain Research, Deutschordenstrasse 46, 60528 Frankfurt am Main, Germany, and.,the Max Planck Institute of Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
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174
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Roosen DA, Cookson MR. LRRK2 at the interface of autophagosomes, endosomes and lysosomes. Mol Neurodegener 2016; 11:73. [PMID: 27927216 PMCID: PMC5142374 DOI: 10.1186/s13024-016-0140-1] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 12/03/2016] [Indexed: 02/07/2023] Open
Abstract
Over the past 20 years, substantial progress has been made in identifying the underlying genetics of Parkinson's disease (PD). Of the known genes, LRRK2 is a major genetic contributor to PD. However, the exact function of LRRK2 remains to be elucidated. In this review, we discuss how familial forms of PD have led us to hypothesize that alterations in endomembrane trafficking play a role in the pathobiology of PD. We will discuss the major observations that have been made to elucidate the role of LRRK2 in particular, including LRRK2 animal models and high-throughput proteomics approaches. Taken together, these studies strongly support a role of LRRK2 in vesicular dynamics. We also propose that targeting these pathways may not only be beneficial for developing therapeutics for LRRK2-driven PD, but also for other familial and sporadic cases.
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Affiliation(s)
- Dorien A. Roosen
- Cell Biology and Gene Expression Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bldg. 35, 35 Convent Drive, Bethesda, MD 20892-3707 USA
- School of Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AP UK
| | - Mark R. Cookson
- Cell Biology and Gene Expression Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bldg. 35, 35 Convent Drive, Bethesda, MD 20892-3707 USA
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175
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Fassy F, Dureuil C, Lamberton A, Mathieu M, Michot N, Ronan B, Pasquier B. In Vitro Characterization of VPS34 Lipid Kinase Inhibition by Small Molecules. Methods Enzymol 2016; 587:447-464. [PMID: 28253972 DOI: 10.1016/bs.mie.2016.09.070] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
VPS34 is a class III phosphoinositide 3-kinase that acts on vesicle trafficking. This kinase has recently attracted significant attention because of the function it plays in the machinery involved in the early steps of autophagy. Moreover, because significant progress had been made in the optimization of specific kinase inhibitors, its potential to be targeted by catalytic inhibitors has been investigated by different groups. The aim of this review is to present the key in vitro assays necessary for characterizing inhibitors of the catalytic activity of VPS34. The review covers catalytic (IC50 on purified recombinant protein) and binding assays (KD, ka, kd on purified recombinant protein), and a cell-based assay (IC50 in GFP-FYVE expressing cell line). The methodology for crystallization of VPS34 protein is also presented as it can provide guidance for the design by medicinal chemistry of small molecular mass kinase inhibitor.
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Affiliation(s)
- F Fassy
- Sanofi, Quai Jules Guesde, Vitry Sur Seine, Paris, France
| | - C Dureuil
- Sanofi, Quai Jules Guesde, Vitry Sur Seine, Paris, France
| | - A Lamberton
- Sanofi, Quai Jules Guesde, Vitry Sur Seine, Paris, France
| | - M Mathieu
- Sanofi, Quai Jules Guesde, Vitry Sur Seine, Paris, France
| | - N Michot
- Sanofi, Quai Jules Guesde, Vitry Sur Seine, Paris, France
| | - B Ronan
- Sanofi, Quai Jules Guesde, Vitry Sur Seine, Paris, France
| | - B Pasquier
- Sanofi, Quai Jules Guesde, Vitry Sur Seine, Paris, France.
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176
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Uchida Y, Rutaganira FU, Jullié D, Shokat KM, von Zastrow M. Endosomal Phosphatidylinositol 3-Kinase Is Essential for Canonical GPCR Signaling. Mol Pharmacol 2016; 91:65-73. [PMID: 27821547 DOI: 10.1124/mol.116.106252] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 11/04/2016] [Indexed: 02/04/2023] Open
Abstract
G protein-coupled receptors (GPCRs), the largest family of signaling receptors, are critically regulated by endosomal trafficking, suggesting that endosomes might provide new strategies for manipulating GPCR signaling. Here we test this hypothesis by focusing on class III phosphatidylinositol 3-kinase (Vps34), which is an essential regulator of endosomal trafficking. We verify that Vps34 is required for recycling of the β2-adrenoceptor (β2AR), a prototypical GPCR, and then investigate the effects of Vps34 inhibition on the canonical cAMP response elicited by β2AR activation. Vps34 inhibition impairs the ability of cells to recover this response after prolonged activation, which is in accord with the established role of recycling in GPCR resensitization. In addition, Vps34 inhibition also attenuates the short-term cAMP response, and its effect begins several minutes after initial agonist application. These results establish Vps34 as an essential determinant of both short-term and long-term canonical GPCR signaling, and support the potential utility of the endosomal system as a druggable target for signaling.
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Affiliation(s)
- Yasunori Uchida
- Department of Psychiatry (Y.U., D.J., and M.Z.), Department of Cellular and Molecular Pharmacology (F.U.R., K.M.S., and M.Z.), and Howard Hughes Medical Institute (F.U.R. and K.M.S.), University of California, San Francisco, San Francisco, California
| | - Florentine U Rutaganira
- Department of Psychiatry (Y.U., D.J., and M.Z.), Department of Cellular and Molecular Pharmacology (F.U.R., K.M.S., and M.Z.), and Howard Hughes Medical Institute (F.U.R. and K.M.S.), University of California, San Francisco, San Francisco, California
| | - Damien Jullié
- Department of Psychiatry (Y.U., D.J., and M.Z.), Department of Cellular and Molecular Pharmacology (F.U.R., K.M.S., and M.Z.), and Howard Hughes Medical Institute (F.U.R. and K.M.S.), University of California, San Francisco, San Francisco, California
| | - Kevan M Shokat
- Department of Psychiatry (Y.U., D.J., and M.Z.), Department of Cellular and Molecular Pharmacology (F.U.R., K.M.S., and M.Z.), and Howard Hughes Medical Institute (F.U.R. and K.M.S.), University of California, San Francisco, San Francisco, California
| | - Mark von Zastrow
- Department of Psychiatry (Y.U., D.J., and M.Z.), Department of Cellular and Molecular Pharmacology (F.U.R., K.M.S., and M.Z.), and Howard Hughes Medical Institute (F.U.R. and K.M.S.), University of California, San Francisco, San Francisco, California
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177
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Yamazaki R, Ishibashi T, Baba H, Yamaguchi Y. Knockdown of Unconventional Myosin ID Expression Induced Morphological Change in Oligodendrocytes. ASN Neuro 2016; 8:1759091416669609. [PMID: 27655972 PMCID: PMC5036140 DOI: 10.1177/1759091416669609] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 08/05/2016] [Accepted: 08/22/2016] [Indexed: 11/19/2022] Open
Abstract
Myelin is a special multilamellar structure involved in various functions in the nervous system. In the central nervous system, the oligodendrocyte (OL) produces myelin and has a unique morphology. OLs have a dynamic membrane sorting system associated with cytoskeletal organization, which aids in the production of myelin. Recently, it was reported that the assembly and disassembly of actin filaments is crucial for myelination. However, the partner myosin molecule which associates with actin filaments during the myelination process has not yet been identified. One candidate myosin is unconventional myosin ID (Myo1d) which is distributed throughout central nervous system myelin; however, its function is still unclear. We report here that Myo1d is expressed during later stages of OL differentiation, together with myelin proteolipid protein (PLP). In addition, Myo1d is distributed at the leading edge of the myelin-like membrane in cultured OL, colocalizing mainly with actin filaments, 2',3'-cyclic nucleotide phosphodiesterase and partially with PLP. Myo1d-knockdown with specific siRNA induces significant morphological changes such as the retraction of processes and degeneration of myelin-like membrane, and finally apoptosis. Furthermore, loss of Myo1d by siRNA results in the impairment of intracellular PLP transport. Together, these results suggest that Myo1d may contribute to membrane dynamics either in wrapping or transporting of myelin membrane proteins during formation and maintenance of myelin.
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Affiliation(s)
- Reiji Yamazaki
- Department of Molecular Neurobiology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Tomoko Ishibashi
- Department of Molecular Neurobiology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Hiroko Baba
- Department of Molecular Neurobiology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Yoshihide Yamaguchi
- Department of Molecular Neurobiology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
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178
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Regulation of autophagy by mitochondrial phospholipids in health and diseases. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:114-129. [PMID: 27502688 DOI: 10.1016/j.bbalip.2016.08.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 07/28/2016] [Accepted: 08/04/2016] [Indexed: 12/16/2022]
Abstract
Autophagy is an evolutionarily conserved mechanism that maintains nutrient homeostasis by degrading protein aggregates and damaged organelles. Autophagy is reduced in aging, which is implicated in the pathogenesis of aging-related diseases, including cancers, obesity, type 2 diabetes, cardiovascular diseases, and neurodegenerative diseases. Mitochondria-derived phospholipids cardiolipin, phosphatidylethanolamine, and phosphatidylglycerol are critical throughout the autophagic process, from initiation and phagophore formation to elongation and fusion with endolysosomal vesicles. Cardiolipin is also required for mitochondrial fusion and fission, an important step in isolating dysfunctional mitochondria for mitophagy. Furthermore, genetic screen in yeast has identified a surprising role for cardiolipin in regulating lysosomal function. Phosphatidylethanolamine plays a pivotal role in supporting the autophagic process, including autophagosome elongation as part of lipidated Atg8/LC3. An emerging role for phosphatidylglycerol in AMPK and mTORC1 signaling as well as mitochondrial fission may provide the first glimpse into the function of phosphatidylglycerol apart from being a precursor for cardiolipin. This review examines the effects of manipulating phospholipids on autophagy and mitophagy in health and diseases, as well as current limitations in the field. This article is part of a Special Issue entitled: Lipids of Mitochondria edited by Guenther Daum.
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179
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Nagpal A, Ndamukong I, Hassan A, Avramova Z, Baluška F. Subcellular localizations of Arabidopsis myotubularins MTM1 and MTM2 suggest possible functions in vesicular trafficking between ER and cis-Golgi. JOURNAL OF PLANT PHYSIOLOGY 2016; 200:45-52. [PMID: 27340857 DOI: 10.1016/j.jplph.2016.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 06/03/2016] [Accepted: 06/03/2016] [Indexed: 06/06/2023]
Abstract
The two Arabidopsis genes AtMTM1 and AtMTM2 encode highly similar phosphoinositide 3-phosphatases from the myotubularin family. Despite the high-level conservation of structure and biochemical activities, their physiological roles have significantly diverged. The nature of a membrane and the concentrations of their membrane-anchored substrates (PtdIns3P or PtdIns3,5P2) and/or products (PtdIns5P and PtdIns) are considered critical for determining the functional specificity of myotubularins. We have performed comprehensive analyses of the subcellular localization of AtMTM1 and AtMTM2 using a variety of specific constructs transiently expressed in Nicotiana benthamiana leaf epidermal cells under the control of 35S promoter. AtMTM1 co-localized preferentially with cis-Golgi membranes, while AtMTM2 associated predominantly with ER membranes. In a stark contrast with animal/human MTMs, neither AtMTM1 nor AtMTM2 co-localizes with early or late endosomes or with TGN/EE compartments, making them unlikely participants in the endosomal trafficking system. Localization of the AtMTM2 is sensitive to cold and osmotic stress challenges. In contrast to animal myotubularins, Arabidopsis myotubularins do not associate with endosomes. Our results suggest that Arabidopsis myotubularins play a role in the vesicular trafficking between ER exit sites and cis-Golgi elements. The significance of these results is discussed also in the context of stress biology and plant autophagy.
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Affiliation(s)
| | - Ivan Ndamukong
- School of Biological Sciences, UNL, Lincoln NE, 68588, United States
| | - Ammar Hassan
- IZMB, University of Bonn, Kirschalle 1, 53115 Bonn, Germany
| | - Zoya Avramova
- School of Biological Sciences, UNL, Lincoln NE, 68588, United States.
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180
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Mittal R, Grati M, Sedlacek M, Yuan F, Chang Q, Yan D, Lin X, Kachar B, Farooq A, Chapagain P, Zhang Y, Liu XZ. Characterization of ATPase Activity of P2RX2 Cation Channel. Front Physiol 2016; 7:186. [PMID: 27252659 PMCID: PMC4878533 DOI: 10.3389/fphys.2016.00186] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/09/2016] [Indexed: 12/31/2022] Open
Abstract
P2X purinergic receptors are plasma membrane ATP-dependent cation channels that are broadly distributed in the mammalian tissues. P2RX2 is a modulator of auditory sensory hair cell mechanotransduction and plays an important role in hair cell tolerance to noise. In this study, we demonstrate for the first time in vitro and in cochlear neuroepithelium, that P2RX2 possesses the ATPase activity. We observed that the P2RX2 V60L human deafness mutation alters its ability to bind ATP, while the G353R has no effect on ATP binding or hydrolysis. A non-hydrolysable ATP assay using HEK293 cells suggests that ATP hydrolysis plays a significant role in the opening and gating of the P2RX2 ion channel. Moreover, the results of structural modeling of the molecule was in agreement with our experimental observations. These novel findings suggest the intrinsic ATPase activity of P2RX2 and provide molecular insights into the channel opening.
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Affiliation(s)
- Rahul Mittal
- Department of Otolaryngology, University of Miami Miller School of Medicine Miami, FL, USA
| | - M'hamed Grati
- Department of Otolaryngology, University of Miami Miller School of Medicine Miami, FL, USA
| | - Miloslav Sedlacek
- Laboratory of Cell Structure and Dynamics, Section on Structural Cell Biology, National Institute on Deafness and Other Communication Disorders, National Institutes of Health Bethesda, MD, USA
| | - Fenghua Yuan
- Department of Biochemistry, University of Miami Leonard M. Miller School of Medicine Miami, FL, USA
| | - Qing Chang
- Department of Otolaryngology, Emory University Atlanta, GA, USA
| | - Denise Yan
- Department of Otolaryngology, University of Miami Miller School of Medicine Miami, FL, USA
| | - Xi Lin
- Department of Otolaryngology, Emory University Atlanta, GA, USA
| | - Bechara Kachar
- Laboratory of Cell Structure and Dynamics, Section on Structural Cell Biology, National Institute on Deafness and Other Communication Disorders, National Institutes of Health Bethesda, MD, USA
| | - Amjad Farooq
- Department of Biochemistry, University of Miami Leonard M. Miller School of Medicine Miami, FL, USA
| | - Prem Chapagain
- Department of Physics, Florida International University Miami, FL, USA
| | - Yanbin Zhang
- Department of Biochemistry, University of Miami Leonard M. Miller School of Medicine Miami, FL, USA
| | - Xue Z Liu
- Department of Otolaryngology, University of Miami Miller School of MedicineMiami, FL, USA; Department of Biochemistry, University of Miami Leonard M. Miller School of MedicineMiami, FL, USA; Department of Otolaryngology, Central South University, Xiangya HospitalChangsha, China
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181
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Marat AL, Haucke V. Phosphatidylinositol 3-phosphates-at the interface between cell signalling and membrane traffic. EMBO J 2016; 35:561-79. [PMID: 26888746 DOI: 10.15252/embj.201593564] [Citation(s) in RCA: 177] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 01/26/2016] [Indexed: 12/31/2022] Open
Abstract
Phosphoinositides (PIs) form a minor class of phospholipids with crucial functions in cell physiology, ranging from cell signalling and motility to a role as signposts of compartmental membrane identity. Phosphatidylinositol 3-phosphates are present at the plasma membrane and within the endolysosomal system, where they serve as key regulators of both cell signalling and of intracellular membrane traffic. Here, we provide an overview of the metabolic pathways that regulate cellular synthesis of PI 3-phosphates at distinct intracellular sites and discuss the mechanisms by which these lipids regulate cell signalling and membrane traffic. Finally, we provide a framework for how PI 3-phosphate metabolism is integrated into the cellular network.
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Affiliation(s)
- Andrea L Marat
- Leibniz Institut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Volker Haucke
- Leibniz Institut für Molekulare Pharmakologie (FMP), Berlin, Germany
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