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Zhao M, Zhang S, Wan W, Zhou C, Li N, Cheng R, Yu Y, Ouyang X, Zhou D, Jiao J, Xiong X. Coxiella burnetii effector CvpE maintains biogenesis of Coxiella-containing vacuoles by suppressing lysosome tubulation through binding PI(3)P and perturbing PIKfyve activity on lysosomes. Virulence 2024; 15:2350893. [PMID: 38725096 PMCID: PMC11085968 DOI: 10.1080/21505594.2024.2350893] [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: 10/26/2023] [Accepted: 04/27/2024] [Indexed: 05/12/2024] Open
Abstract
Coxiella burnetii (C. burnetii) is the causative agent of Q fever, a zoonotic disease. Intracellular replication of C. burnetii requires the maturation of a phagolysosome-like compartment known as the replication permissive Coxiella-containing vacuole (CCV). Effector proteins secreted by the Dot/Icm secretion system are indispensable for maturation of a single large CCV by facilitating the fusion of promiscuous vesicles. However, the mechanisms of CCV maintenance and evasion of host cell clearance remain to be defined. Here, we show that C. burnetii secreted Coxiella vacuolar protein E (CvpE) contributes to CCV biogenesis by inducing lysosome-like vacuole (LLV) enlargement. LLV fission by tubulation and autolysosome degradation is impaired in CvpE-expressing cells. Subsequently, we found that CvpE suppresses lysosomal Ca2+ channel transient receptor potential channel mucolipin 1 (TRPML1) activity in an indirect manner, in which CvpE binds phosphatidylinositol 3-phosphate [PI(3)P] and perturbs PIKfyve activity in lysosomes. Finally, the agonist of TRPML1, ML-SA5, inhibits CCV biogenesis and C. burnetii replication. These results provide insight into the mechanisms of CCV maintenance by CvpE and suggest that the agonist of TRPML1 can be a novel potential treatment that does not rely on antibiotics for Q fever by enhancing Coxiella-containing vacuoles (CCVs) fission.
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Affiliation(s)
- Mingliang Zhao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Shan Zhang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Weiqiang Wan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- College of Life Sciences, Southwest Forestry University, Kunming, Yunnan, China
| | - Chunyu Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- School of Public Health, Mudanjiang Medical University, Mudanjiang, Heilongjiang, China
| | - Nana Li
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- School of Public Health, Anhui Medical University, Hefei, Anhui, China
| | - Ruxi Cheng
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Yonghui Yu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Xuan Ouyang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Dongsheng Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Jun Jiao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Xiaolu Xiong
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
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2
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Mehta K, Yentsch H, Lee J, Yook Y, Lee KY, Gao TT, Tsai NP, Zhang K. Phosphatidylinositol-3-phosphate mediates Arc capsid secretion through the multivesicular body pathway. Proc Natl Acad Sci U S A 2024; 121:e2322422121. [PMID: 39178227 PMCID: PMC11363301 DOI: 10.1073/pnas.2322422121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Accepted: 07/30/2024] [Indexed: 08/25/2024] Open
Abstract
Activity-regulated cytoskeleton-associated protein (Arc/Arg3.1) is an immediate early gene that plays a vital role in learning and memory. Arc protein has structural and functional properties similar to viral Group-specific antigen (Gag) protein and mediates the intercellular RNA transfer through virus-like capsids. However, the regulators and secretion pathway through which Arc capsids maneuver cargos are unclear. Here, we identified that phosphatidylinositol-3-phosphate (PI3P) mediates Arc capsid assembly and secretion through the endosomal-multivesicular body (MVB) pathway. Indeed, reconstituted Arc protein preferably binds to PI3P. In HEK293T cells, Arc forms puncta that colocalize with FYVE, an endosomal PI3P marker, as well as Rab5 and CD63, early endosomal and MVB markers, respectively. Superresolution imaging resolves Arc accumulates within the intraluminal vesicles of MVB. CRISPR double knockout of RalA and RalB, crucial GTPases for MVB biogenesis and exocytosis, severely reduces the Arc-mediated RNA transfer efficiency. RalA/B double knockdown in cultured rat cortical neurons increases the percentage of mature dendritic spines. Intake of extracellular vesicles purified from Arc-expressing wild-type, but not RalA/B double knockdown, cells in mouse cortical neurons reduces their surface GlutA1 levels. These results suggest that unlike the HIV Gag, whose membrane targeting requires interaction with plasma-membrane-specific phosphatidyl inositol (4,5) bisphosphate (PI(4,5)P2), the assembly of Arc capsids is mediated by PI3P at endocytic membranes. Understanding Arc's secretion pathway helps gain insights into its role in intercellular cargo transfer and highlights the commonality and distinction of trafficking mechanisms between structurally resembled capsid proteins.
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Affiliation(s)
- Kritika Mehta
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL61801
- NSF Science and Technology Center for Quantitative Cell Biology (STC-QCB) Center, University of Illinois Urbana-Champaign, Urbana, IL61801
| | - Henry Yentsch
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL61801
| | - Jungbin Lee
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL61801
| | - Yeeun Yook
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, IL61801
| | - Kwan Young Lee
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, IL61801
| | - Tianyu Terry Gao
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL61801
| | - Nien-Pei Tsai
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, IL61801
| | - Kai Zhang
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL61801
- NSF Science and Technology Center for Quantitative Cell Biology (STC-QCB) Center, University of Illinois Urbana-Champaign, Urbana, IL61801
- Center for Biophysics and Quantitative Biology, College of Liberal Arts and Sciences, University of Illinois Urbana-Champaign, Urbana, IL61801
- Neuroscience Program, College of Liberal Arts and Sciences, University of Illinois Urbana-Champaign, Urbana, IL61801
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL61801
- Cancer Center at Illinois, University of Illinois Urbana-Champaign, Urbana, IL61801
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3
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Tanaka Y, Kozuma L, Hino H, Takeya K, Eto M. Abemaciclib and Vacuolin-1 decrease aggregate-prone TDP-43 accumulation by accelerating autophagic flux. Biochem Biophys Rep 2024; 38:101705. [PMID: 38596406 PMCID: PMC11001778 DOI: 10.1016/j.bbrep.2024.101705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 03/14/2024] [Accepted: 03/29/2024] [Indexed: 04/11/2024] Open
Abstract
(Macro)autophagy is a cellular degradation system for unnecessary materials, such as aggregate-prone TDP-43, a central molecule in neurodegenerative diseases including amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Abemaciclib (Abe) and vacuolin-1 (Vac) treatments are known to induce vacuoles characterized by an autophagosome and a lysosome component, suggesting that they facilitate autophagosome-lysosome fusion. However, it remains unknown whether Abe and Vac suppress the accumulation of aggregate-prone TDP-43 by accelerating autophagic flux. In the present study, the Abe and Vac treatment dose-dependently reduced the GFP/RFP ratio in SH-SY5Y neuroblastoma cells stably expressing the autophagic flux marker GFP-LC3-RFP-LC3ΔG. Abe and Vac also increased the omegasome marker GFP-ATG13 signal and the autophagosome marker mCherry-LC3 localized to the lysosome marker LAMP1-GFP. The Abe and Vac treatment decreased the intracellular level of the lysosome marker LAMP1-GFP in SH-SY5Y cells stably expressing LAMP1-GFP, but did not increase the levels of LAMP1-GFP, the autophagosome marker LC3-II, or the multivesicular body marker TSG101 in the extracellular vesicle-enriched fraction. Moreover, Abe and Vac treatment autophagy-dependently inhibited GFP-tagged aggregate-prone TDP-43 accumulation. The results of a PI(3)P reporter assay using the fluorescent protein tagged-2 × FYVE and LAMP1-GFP indicated that Abe and Vac increased the intensity of the PI(3)P signal on lysosomes. A treatment with the VPS34 inhibitor wortmannin (WM) suppressed Abe-/Vac-facilitated autophagic flux and the degradation of GFP-tagged aggregate-prone TDP-43. Collectively, these results suggest that Abe and Vac degrade aggregate-prone TDP-43 by accelerating autophagosome formation and autophagosome-lysosome fusion through the formation of PI(3)P.
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Affiliation(s)
- Yoshinori Tanaka
- Biochemistry Unit, Faculty of Veterinary Medicine, Okayama University of Science, Imabari-shi, Ehime, Japan
| | - Lina Kozuma
- Biochemistry Unit, Faculty of Veterinary Medicine, Okayama University of Science, Imabari-shi, Ehime, Japan
| | - Hirotsugu Hino
- Division of Anatomical Science, Department of Functional Morphology, Nihon University School of Medicine, Itabashi-ku, Tokyo, Japan
| | - Kosuke Takeya
- Biochemistry Unit, Faculty of Veterinary Medicine, Okayama University of Science, Imabari-shi, Ehime, Japan
| | - Masumi Eto
- Biochemistry Unit, Faculty of Veterinary Medicine, Okayama University of Science, Imabari-shi, Ehime, Japan
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Sanyal A, Scanavachi G, Somerville E, Saminathan A, Nair A, Oikonomou A, Hatzakis NS, Kirchhausen T. Constitutive Endolysosomal Perforation in Neurons allows Induction of α-Synuclein Aggregation by Internalized Pre-Formed Fibrils. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.30.573738. [PMID: 38260258 PMCID: PMC10802249 DOI: 10.1101/2023.12.30.573738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The endocytic pathway is both an essential route of molecular uptake in cells and a potential entry point for pathology-inducing cargo. The cell-to-cell spread of cytotoxic aggregates, such as those of α-synuclein (α-syn) in Parkinson's Disease (PD), exemplifies this duality. Here we used a human iPSC-derived induced neuronal model (iNs) prone to death mediated by aggregation in late endosomes and lysosomes of endogenous α-syn, seeded by internalized pre-formed fibrils of α-syn (PFFs). This PFF-mediated death was not observed with parental iPSCs or other non-neuronal cells. Using live-cell optical microscopy to visualize the read out of biosensors reporting endo-lysosome wounding, we discovered that up to about 10% of late endosomes and lysosomes in iNs exhibited spontaneous constitutive perforations, regardless of the presence of internalized PFFs. This wounding, absent in parental iPSCs and non-neuronal cells, corresponded to partial damage by nanopores in the limiting membranes of a subset of endolysosomes directly observed by volumetric focused ion beam scanning electron microscopy (FIB-SEM) in iNs and in CA1 pyramidal neurons from mouse brain, and not found in iPSCs or in other non-neuronal cells in culture or in mouse liver and skin. We suggest that the compromised limiting membranes in iNs and neurons in general are the primary conduit for cytosolic α-syn to access PFFs entrapped within endo-lysosomal lumens, initiating PFF-mediated α-syn aggregation. Significantly, eradicating the intrinsic endolysosomal perforations in iNs by inhibiting the endosomal Phosphatidylinositol-3-Phosphate/Phosphatidylinositol 5-Kinase (PIKfyve kinase) using Apilimod or Vacuolin-1 markedly reduced PFF-induced α-syn aggregation, despite PFFs continuing to enter the endolysosomal compartment. Crucially, this intervention also diminished iN death associated with PFF incubation. Our results reveal the surprising presence of intrinsically perforated endo-lysosomes in neurons, underscoring their crucial early involvement in the genesis of toxic α-syn aggregates induced by internalized PFFs. This discovery offers a basis for employing PIKfyve kinase inhibition as a potential therapeutic strategy to counteract synucleinopathies.
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Affiliation(s)
- Anwesha Sanyal
- Department of Cell Biology, Harvard Medical School, 200 Longwood Ave, Boston, MA 02115, USA
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, 200 Longwood Ave, Boston, MA 02115, USA
| | - Gustavo Scanavachi
- Department of Cell Biology, Harvard Medical School, 200 Longwood Ave, Boston, MA 02115, USA
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, 200 Longwood Ave, Boston, MA 02115, USA
| | - Elliott Somerville
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, 200 Longwood Ave, Boston, MA 02115, USA
| | - Anand Saminathan
- Department of Cell Biology, Harvard Medical School, 200 Longwood Ave, Boston, MA 02115, USA
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, 200 Longwood Ave, Boston, MA 02115, USA
| | - Athul Nair
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, 200 Longwood Ave, Boston, MA 02115, USA
| | | | - Nikos S. Hatzakis
- Department of Chemistry University of Copenhagen, 2100 Copenhagen, Denmark
| | - Tom Kirchhausen
- Department of Cell Biology, Harvard Medical School, 200 Longwood Ave, Boston, MA 02115, USA
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, 200 Longwood Ave, Boston, MA 02115, USA
- Department of Pediatrics, Harvard Medical School, 200 Longwood Ave, Boston, MA 02115, USA
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5
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Mehta K, Yentsch H, Lee J, Gao TT, Zhang K. Phosphatidylinositol 3-phosphate mediates Arc capsids secretion through the multivesicular body pathway. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.19.572392. [PMID: 38187623 PMCID: PMC10769229 DOI: 10.1101/2023.12.19.572392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Activity-regulated cytoskeleton-associated protein (Arc/Arg3.1) is an immediate early gene that plays a vital role in learning and memory. The recent discovery that Arc mediates the inter-neuronal RNA transfer implies its role in regulating neuronal functions across long distances. Arc protein has structural and functional properties similar to viral Group-specific antigen (Gag). By assembling into high-order, virus-like capsids, Arc mediates the intercellular RNA transfer. However, the exact secretion pathway through which Arc capsids maneuver cargos is unclear. Here, we identified that Arc capsids assemble and secrete through the endosomal-multivesicular body (MVB) pathway. Arc's endosomal entry is likely mediated by phosphatidylinositol-3-phosphate (PI3P). Indeed, reconstituted Arc protein preferably binds to PI3P. In mammalian cells, Arc forms puncta that colocalizes with FYVE, an endosomal PI3P marker, and competitive binding to PI3P via prolonged FYVE expression reduces the average number of Arc puncta per cell. Overexpression of MTMR1, a PI3P phosphatase, significantly reduces Arc capsid secretion. Arc capsids secrete through the endosomal-MVB axis as extracellular vesicles. Live-cell imaging shows that fluorescently labeled Arc primarily colocalizes Rab5 and CD63, early endosomal and MVB markers, respectively. Superresolution imaging resolves Arc accumulates within the intraluminal vesicles of MVB. CRISPR double knockout of RalA and RalB, crucial GTPases for MVB biogenesis and exocytosis, severely reduces Arc-mediated RNA transfer efficiency. These results suggest that, unlike the Human Immunodeficiency Virus Gag, which assembles on and bud off from the plasma membrane, Arc capsids assemble at the endocytic membranes of the endosomal-MVB pathway mediated by PI3P. Understanding Arc's secretion pathway helps gain insights into its role in intercellular cargo transfer and highlights the commonality and distinction of trafficking mechanisms between structurally resembled capsid proteins.
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6
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Rivero-Ríos P, Weisman LS. A signaling lipid drives synapse formation. Science 2023; 382:155-156. [PMID: 37824634 DOI: 10.1126/science.adk5037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
Phosphatidylinositol 3,5-bisphosphate enables transport of proteins to synaptic sites.
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Affiliation(s)
- Pilar Rivero-Ríos
- Life Sciences Institute, University of Michigan-Ann Arbor, Ann Arbor, MI, USA
| | - Lois S Weisman
- Life Sciences Institute, University of Michigan-Ann Arbor, Ann Arbor, MI, USA
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Tsukahara T, Kethireddy S, Bonefas K, Chen A, Sutton BLM, Dou Y, Iwase S, Sutton MA. Division of labor among H3K4 Methyltransferases Defines Distinct Facets of Homeostatic Plasticity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.20.558734. [PMID: 37790395 PMCID: PMC10542164 DOI: 10.1101/2023.09.20.558734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Heterozygous mutations in any of the six H3K4 methyltransferases (KMT2s) result in monogenic neurodevelopmental disorders, indicating nonredundant yet poorly understood roles of this enzyme family in neurodevelopment. Recent evidence suggests that histone methyltransferase activity may not be central to KMT2 functions; however, the enzymatic activity is evolutionarily conserved, implicating the presence of selective pressure to maintain the catalytic activity. Here, we show that H3K4 methylation is dynamically regulated during prolonged alteration of neuronal activity. The perturbation of H3K4me by the H3.3K4M mutant blocks synaptic scaling, a form of homeostatic plasticity that buffers the impact of prolonged reductions or increases in network activity. Unexpectedly, we found that the six individual enzymes are all necessary for synaptic scaling and that the roles of KMT2 enzymes segregate into evolutionary-defined subfamilies: KMT2A and KMT2B (fly-Trx homologs) for synaptic downscaling, KMT2C and KMT2D (Trr homologs) for upscaling, and KMT2F and KMT2G (dSet homologs) for both directions. Selective blocking of KMT2A enzymatic activity by a small molecule and targeted disruption of the enzymatic domain both blocked the synaptic downscaling and interfered with the activity-dependent transcriptional program. Furthermore, our study revealed specific phases of synaptic downscaling, i.e., induction and maintenance, in which KMT2A and KMT2B play distinct roles. These results suggest that mammalian brains have co-opted intricate H3K4me installation to achieve stability of the expanding neuronal circuits.
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Affiliation(s)
- Takao Tsukahara
- Michigan Neuroscience Institute, University of Michigan Medical School, Ann Arbor, Michigan
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Saini Kethireddy
- College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, Michigan
| | - Katherine Bonefas
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan
| | - Alex Chen
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan
| | - Brendan LM Sutton
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan
| | - Yali Dou
- Department of Medicine and Department of Biochemistry and Molecular Medicine, Keck School of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Shigeki Iwase
- Michigan Neuroscience Institute, University of Michigan Medical School, Ann Arbor, Michigan
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan
| | - Michael A. Sutton
- Michigan Neuroscience Institute, University of Michigan Medical School, Ann Arbor, Michigan
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan
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Vines JH, Maib H, Buckley CM, Gueho A, Zhu Z, Soldati T, Murray DH, King JS. A PI(3,5)P2 reporter reveals PIKfyve activity and dynamics on macropinosomes and phagosomes. J Cell Biol 2023; 222:e202209077. [PMID: 37382666 PMCID: PMC10309190 DOI: 10.1083/jcb.202209077] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 05/12/2023] [Accepted: 06/13/2023] [Indexed: 06/30/2023] Open
Abstract
Phosphoinositide signaling lipids (PIPs) are key regulators of membrane identity and trafficking. Of these, PI(3,5)P2 is one of the least well-understood, despite key roles in many endocytic pathways including phagocytosis and macropinocytosis. PI(3,5)P2 is generated by the phosphoinositide 5-kinase PIKfyve, which is critical for phagosomal digestion and antimicrobial activity. However PI(3,5)P2 dynamics and regulation remain unclear due to lack of reliable reporters. Using the amoeba Dictyostelium discoideum, we identify SnxA as a highly selective PI(3,5)P2-binding protein and characterize its use as a reporter for PI(3,5)P2 in both Dictyostelium and mammalian cells. Using GFP-SnxA, we demonstrate that Dictyostelium phagosomes and macropinosomes accumulate PI(3,5)P2 3 min after engulfment but are then retained differently, indicating pathway-specific regulation. We further find that PIKfyve recruitment and activity are separable and that PIKfyve activation stimulates its own dissociation. SnxA is therefore a new tool for reporting PI(3,5)P2 in live cells that reveals key mechanistic details of the role and regulation of PIKfyve/PI(3,5)P2.
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Affiliation(s)
- James H. Vines
- School of Biosciences, University of Sheffield, Firth Court Western Bank, Sheffield, UK
| | - Hannes Maib
- Division of Molecular, Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Catherine M. Buckley
- School of Biosciences, University of Sheffield, Firth Court Western Bank, Sheffield, UK
| | - Aurelie Gueho
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - Zhou Zhu
- School of Biosciences, University of Sheffield, Firth Court Western Bank, Sheffield, UK
| | - Thierry Soldati
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - David H. Murray
- Division of Molecular, Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Jason S. King
- School of Biosciences, University of Sheffield, Firth Court Western Bank, Sheffield, UK
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Huda M, Bektas SN, Bekdas B, Caydasi AK. The signalling lipid PI3,5P 2 is essential for timely mitotic exit. Open Biol 2023; 13:230125. [PMID: 37751887 PMCID: PMC10522413 DOI: 10.1098/rsob.230125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 08/15/2023] [Indexed: 09/28/2023] Open
Abstract
Coordination of mitotic exit with chromosome segregation is key for successful mitosis. Mitotic exit in budding yeast is executed by the mitotic exit network (MEN), which is negatively regulated by the spindle position checkpoint (SPOC). SPOC kinase Kin4 is crucial for SPOC activation in response to spindle positioning defects. Here, we report that the lysosomal signalling lipid phosphatidylinositol-3,5-bisphosphate (PI3,5P2) has an unanticipated role in the timely execution of mitotic exit. We show that the lack of PI3,5P2 causes a delay in mitotic exit, whereas elevated levels of PI3,5P2 accelerates mitotic exit in mitotic exit defective cells. Our data indicate that PI3,5P2 promotes mitotic exit in part through impairment of Kin4. This process is largely dependent on the known PI3,5P2 effector protein Atg18. Our work thus uncovers a novel link between PI3,5P2 and mitotic exit.
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Affiliation(s)
- Mariam Huda
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Seyma Nur Bektas
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Baris Bekdas
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Ayse Koca Caydasi
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
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10
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Rivero-Ríos P, Tsukahara T, Uygun T, Chen A, Chavis GD, Giridharan SSP, Iwase S, Sutton MA, Weisman LS. Recruitment of the SNX17-Retriever recycling pathway regulates synaptic function and plasticity. J Cell Biol 2023; 222:e202207025. [PMID: 37141105 PMCID: PMC10165670 DOI: 10.1083/jcb.202207025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 03/10/2023] [Accepted: 04/11/2023] [Indexed: 05/05/2023] Open
Abstract
Trafficking of cell-surface proteins from endosomes to the plasma membrane is a key mechanism to regulate synaptic function. In non-neuronal cells, proteins recycle to the plasma membrane either via the SNX27-Retromer-WASH pathway or via the recently discovered SNX17-Retriever-CCC-WASH pathway. While SNX27 is responsible for the recycling of key neuronal receptors, the roles of SNX17 in neurons are less understood. Here, using cultured hippocampal neurons, we demonstrate that the SNX17 pathway regulates synaptic function and plasticity. Disruption of this pathway results in a loss of excitatory synapses and prevents structural plasticity during chemical long-term potentiation (cLTP). cLTP drives SNX17 recruitment to synapses, where its roles are in part mediated by regulating the surface expression of β1-integrin. SNX17 recruitment relies on NMDAR activation, CaMKII signaling, and requires binding to the Retriever and PI(3)P. Together, these findings provide molecular insights into the regulation of SNX17 at synapses and define key roles for SNX17 in synaptic maintenance and in regulating enduring forms of synaptic plasticity.
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Affiliation(s)
- Pilar Rivero-Ríos
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Takao Tsukahara
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA
| | - Tunahan Uygun
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Alex Chen
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Garrett D. Chavis
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA
- Molecular and Integrative Physiology Graduate Program, University, Ann Arbor, MI, USA
| | - Sai Srinivas Panapakkam Giridharan
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Shigeki Iwase
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Michael A. Sutton
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
- Molecular and Integrative Physiology Graduate Program, University, Ann Arbor, MI, USA
| | - Lois S. Weisman
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
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11
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Llorente A, Arora GK, Grenier SF, Emerling BM. PIP kinases: A versatile family that demands further therapeutic attention. Adv Biol Regul 2023; 87:100939. [PMID: 36517396 PMCID: PMC9992244 DOI: 10.1016/j.jbior.2022.100939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022]
Abstract
Phosphoinositides are membrane-localized phospholipids that regulate a plethora of essential cellular processes. These lipid signaling molecules are critical for cell homeostasis and therefore their levels are strictly regulated by the coordinated action of several families of lipid kinases and phosphatases. In this review, we provide a focused perspective on the phosphatidylinositol phosphate kinase (PIPK) family and the three subfamilies that compose it: Type I PIPKs or phosphatidylinositol-4-phosphate 5-kinases (PI4P5Ks), Type II PIPKs or phosphatidylinositol-5-phosphate 4-kinases (PI5P4Ks), and Type III PIPKs or phosphatidylinositol-3-phosphate 5-kinases (PIKfyve). Each subfamily is responsible for catalyzing a hydroxyl phosphorylation on specific phosphoinositide species to generate a double phosphorylated lipid, therefore regulating the levels of both substrate and product. Here, we summarize our current knowledge about the functions and regulation of each PIPK subfamily. Further, we highlight the roles of these kinases in various in vivo genetic models and give an overview of their involvement in multiple pathological conditions. The phosphoinositide field has been long focused on targeting PI3K signaling, but growing evidence suggests that it is time to draw attention to the other phosphoinositide kinases. The discovery of the involvement of PIPKs in the pathogenesis of multiple diseases has prompted substantial efforts to turn these enzymes into pharmacological targets. An increasingly refined knowledge of the biology of PIPKs in a variety of in vitro and in vivo models will facilitate the development of effective approaches for therapeutic intervention with the potential to translate into meaningful clinical benefits for patients suffering from cancer, immunological and infectious diseases, and neurodegenerative disorders.
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Affiliation(s)
- Alicia Llorente
- Cell and Molecular Biology of Cancer Program, Sanford Burnham Prebys, La Jolla, CA, 92037, USA
| | - Gurpreet K Arora
- Cell and Molecular Biology of Cancer Program, Sanford Burnham Prebys, La Jolla, CA, 92037, USA
| | - Shea F Grenier
- Cell and Molecular Biology of Cancer Program, Sanford Burnham Prebys, La Jolla, CA, 92037, USA
| | - Brooke M Emerling
- Cell and Molecular Biology of Cancer Program, Sanford Burnham Prebys, La Jolla, CA, 92037, USA.
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12
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Leray X, Hilton JK, Nwangwu K, Becerril A, Mikusevic V, Fitzgerald G, Amin A, Weston MR, Mindell JA. Tonic inhibition of the chloride/proton antiporter ClC-7 by PI(3,5)P2 is crucial for lysosomal pH maintenance. eLife 2022; 11:74136. [PMID: 35670560 PMCID: PMC9242644 DOI: 10.7554/elife.74136] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 06/06/2022] [Indexed: 11/13/2022] Open
Abstract
The acidic luminal pH of lysosomes, maintained within a narrow range, is essential for proper degrative function of the organelle and is generated by the action of a V-type H+ ATPase, but other pathways for ion movement are required to dissipate the voltage generated by this process. ClC-7, a Cl-/H+ antiporter responsible for lysosomal Cl- permeability, is a candidate to contribute to the acidification process as part of this ‘counterion pathway’ The signaling lipid PI(3,5)P2 modulates lysosomal dynamics, including by regulating lysosomal ion channels, raising the possibility that it could contribute to lysosomal pH regulation. Here, we demonstrate that depleting PI(3,5)P2 by inhibiting the kinase PIKfyve causes lysosomal hyperacidification, primarily via an effect on ClC-7. We further show that PI(3,5)P2 directly inhibits ClC-7 transport and that this inhibition is eliminated in a disease-causing gain-of-function ClC-7 mutation. Together, these observations suggest an intimate role for ClC-7 in lysosomal pH regulation.
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Affiliation(s)
- Xavier Leray
- Membrane Transport Biophysics Section, National Institute of Neurological Disorders and Stroke
| | - Jacob K Hilton
- Membrane Transport Biophysics Section, National Institute of Neurological Disorders and Stroke
| | - Kamsi Nwangwu
- Membrane Transport Biophysics Section, National Institute of Neurological Disorders and Stroke
| | - Alissa Becerril
- Membrane Transport Biophysics Section, National Institute of Neurological Disorders and Stroke
| | - Vedrana Mikusevic
- Membrane Transport Biophysics Section, National Institute of Neurological Disorders and Stroke
| | - Gabriel Fitzgerald
- Membrane Transport Biophysics Section, National Institute of Neurological Disorders and Stroke
| | - Anowarul Amin
- Membrane Transport Biophysics Section, National Institute of Neurological Disorders and Stroke
| | - Mary R Weston
- Membrane Transport Biophysics Section, National Institute of Neurological Disorders and Stroke
| | - Joseph A Mindell
- Membrane Transport Biophysics Section, National Institute of Neurological Disorders and Stroke
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13
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Yang Y, Liu JJ. Structural LTP: Signal transduction, actin cytoskeleton reorganization, and membrane remodeling of dendritic spines. Curr Opin Neurobiol 2022; 74:102534. [DOI: 10.1016/j.conb.2022.102534] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 02/14/2022] [Accepted: 03/03/2022] [Indexed: 01/05/2023]
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14
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Rivero-Ríos P, Weisman LS. Roles of PIKfyve in multiple cellular pathways. Curr Opin Cell Biol 2022; 76:102086. [PMID: 35584589 PMCID: PMC9108489 DOI: 10.1016/j.ceb.2022.102086] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/27/2022] [Accepted: 04/02/2022] [Indexed: 02/01/2023]
Abstract
Phosphoinositide signaling lipids are crucial for eukaryotes and regulate many aspects of cell function. These signaling molecules are difficult to study because they are extremely low abundance. Here, we focus on two of the lowest abundance phosphoinositides, PI(3,5)P2 and PI(5)P, which play critical roles in cellular homeostasis, membrane trafficking and transcription. Their levels are tightly regulated by a protein complex that includes PIKfyve, Fig4 and Vac14. Importantly, mutations in this complex that decrease PI(3,5)P2 and PI(5)P are linked to human diseases, especially those of the nervous system. Paradoxically, PIKfyve inhibitors which decrease PI(3,5)P2 and PI(5)P, are currently being tested for some neurodegenerative diseases, as well as other diverse diseases including some cancers, and as a treatment for SARS-CoV2 infection. A more comprehensive picture of the pathways that are regulated by PIKfyve will be critical to understand the roles of PI(3,5)P2 and PI(5)P in normal human physiology and in disease.
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Affiliation(s)
- Pilar Rivero-Ríos
- Life Sciences Institute and Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Lois S Weisman
- Life Sciences Institute and Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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15
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Guo Z, Jiang CH, Tong C, Yang Y, Wang Z, Lam SM, Wang D, Li R, Shui G, Shi YS, Liu JJ. Activity-dependent PI4P synthesis by PI4KIIIα regulates long-term synaptic potentiation. Cell Rep 2022; 38:110452. [PMID: 35235793 DOI: 10.1016/j.celrep.2022.110452] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 12/30/2021] [Accepted: 02/07/2022] [Indexed: 01/11/2023] Open
Abstract
Phosphatidylinositol 4-phosphate (PI4P) is a low abundant phospholipid with important roles in lipid transport and membrane trafficking. However, little is known of its metabolism and function in neurons. Here, we investigate its subcellular distribution and functional roles in dendrites of rodent hippocampal neurons during resting state and long-term synaptic potentiation (LTP). We show that neural activity causes dynamic reversible changes in PI4P metabolism in dendrites. Upon LTP induction, PI4KIIIα, a type III phosphatidylinositol 4-kinase, localizes to the dendritic plasma membrane (PM) in a calcium-dependent manner and causes substantial increase in the levels of PI4P. Acute inhibition of PI4KIIIα activity abolishes trafficking of the AMPA-type glutamate receptor to the PM during LTP induction, and silencing of PI4KIIIα expression in the hippocampal CA1 region causes severe impairment of LTP and long-term memory. Collectively, our results identify an essential role for PI4KIIIα-dependent PI4P synthesis in synaptic plasticity of central nervous system neurons.
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Affiliation(s)
- Zhenzhen Guo
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100039, China
| | - Chao-Hua Jiang
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center of Nanjing University, Nanjing 210061, China
| | - Chunfang Tong
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Yanrui Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Zehua Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100039, China
| | - Sin Man Lam
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Dou Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Rui Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100039, China
| | - Guanghou Shui
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Yun Stone Shi
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center of Nanjing University, Nanjing 210061, China
| | - Jia-Jia Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100039, China.
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16
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Giridharan SSP, Luo G, Rivero-Rios P, Steinfeld N, Tronchere H, Singla A, Burstein E, Billadeau DD, Sutton MA, Weisman LS. Lipid kinases VPS34 and PIKfyve coordinate a phosphoinositide cascade to regulate Retriever-mediated recycling on endosomes. eLife 2022; 11:69709. [PMID: 35040777 PMCID: PMC8816382 DOI: 10.7554/elife.69709] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 01/17/2022] [Indexed: 11/13/2022] Open
Abstract
Cell-surface receptors control how cells respond to their environment. Many cell-surface receptors recycle from endosomes to the plasma membrane via a recently discovered pathway, which includes sorting-nexin SNX17, Retriever, WASH and CCC complexes. Here, using mammalian cells, we discover that PIKfyve and its upstream PI3-kinase VPS34 positively regulate this pathway. VPS34 produces PI3P, which is the substrate for PIKfyve to generate PI3,5P2. We show that PIKfyve controls recycling of cargoes including integrins, receptors that control cell migration. Furthermore, endogenous PIKfyve colocalizes with SNX17, Retriever, WASH and CCC complexes on endosomes. Importantly, PIKfyve inhibition results displacement of Retriever and CCC from endosomes. In addition, we show that recruitment of SNX17 is an early step and requires VPS34. These discoveries suggest that VPS34 and PIKfyve coordinate an ordered pathway to regulate recycling from endosomes and suggest how PIKfyve functions in cell migration.
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Affiliation(s)
| | - Guangming Luo
- Department of Cell and Developmental Biology, University of Michigan-Ann Arbor
| | - Pilar Rivero-Rios
- Department of Cell and Developmental Biology, University of Michigan-Ann Arbor
| | - Noah Steinfeld
- Department of Cell and Developmental Biology, University of Michigan-Ann Arbor
| | | | - Amika Singla
- Department of Internal Medicine, The University of Texas Southwestern Medical Center
| | - Ezra Burstein
- Department of Internal Medicine, The University of Texas Southwestern Medical Center
| | | | - Michael A Sutton
- Molecular and Integrative Physiology, University of Michigan-Ann Arbor
| | - Lois S Weisman
- Department of Cell and Developmental Biology, University of Michigan-Ann Arbor
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17
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Hasegawa J, Tokuda E, Yao Y, Sasaki T, Inoki K, Weisman LS. PP2A-dependent TFEB activation is blocked by PIKfyve-induced mTORC1 activity. Mol Biol Cell 2022; 33:ar26. [PMID: 35020443 PMCID: PMC9250387 DOI: 10.1091/mbc.e21-06-0309] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Transcriptional factor EB (TFEB) is a master regulator of genes required for autophagy and lysosomal function. The nuclear localization of TFEB is blocked by the mechanistic target of rapamycin complex 1 (mTORC1)-dependent phosphorylation of TFEB at multiple sites including Ser-211. Here we show that inhibition of PIKfyve, which produces phosphatidylinositol 3,5-bisphosphate on endosomes and lysosomes, causes a loss of Ser-211 phosphorylation and concomitant nuclear localization of TFEB. We found that while mTORC1 activity toward S6K1, as well as other major mTORC1 substrates, is not impaired, PIKfyve inhibition specifically impedes the interaction of TFEB with mTORC1. This suggests that mTORC1 activity on TFEB is selectively inhibited due to loss of mTORC1 access to TFEB. In addition, we found that TFEB activation during inhibition of PIKfyve relies on the ability of protein phosphatase 2A (PP2A) but not calcineurin/PPP3 to dephosphorylate TFEB Ser-211. Thus when PIKfyve is inhibited, PP2A is dominant over mTORC1 for control of TFEB phosphorylation at Ser-S211. Together these findings suggest that mTORC1 and PP2A have opposing roles on TFEB via phosphorylation and dephosphorylation of Ser-211, respectively, and further that PIKfyve inhibits TFEB activity by facilitating mTORC1-dependent phosphorylation of TFEB.
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Affiliation(s)
- Junya Hasegawa
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109, USA.,Department of Biochemical Pathophysiology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Emi Tokuda
- Department of Biochemical Pathophysiology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Yao Yao
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109, USA
| | - Takehiko Sasaki
- Department of Biochemical Pathophysiology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Ken Inoki
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109, USA.,Department of Molecular and Integrative Physiology, University of Michigan Medical School, 1137 East Catherine Street, Ann Arbor, MI 48109, USA.,Department of Internal Medicine, University of Michigan Medical School, 1500 East Medical enter Drive, Ann Arbor, MI 48109, USA
| | - Lois S Weisman
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109, USA.,Department of Cell and Developmental Biology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI 48109
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18
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Qiu S, Lavallée-Adam M, Côté M. Proximity Interactome Map of the Vac14-Fig4 Complex Using BioID. J Proteome Res 2021; 20:4959-4973. [PMID: 34554760 DOI: 10.1021/acs.jproteome.1c00408] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Conversion between phosphatidylinositol-3-phosphate and phosphatidylinositol-3,5-bisphosphate on endosomal membranes is critical for the maturation of early endosomes to late endosomes/lysosomes and is regulated by the PIKfyve-Vac14-Fig4 complex. Despite the importance of this complex for endosomal homeostasis and vesicular trafficking, there is little known about how its activity is regulated or how it interacts with other cellular proteins. Here, we screened for the cellular interactome of Vac14 and Fig4 using proximity-dependent biotin labeling (BioID). After independently screening the interactomes of Vac14 and Fig4, we identified 89 high-confidence protein hits shared by both proteins. Network analysis of these hits revealed pathways with known involvement of the PIKfyve-Vac14-Fig4 complex, including vesicular organization and PI3K/Akt signaling, as well as novel pathways including cell cycle and mitochondrial regulation. We also identified subunits of coatomer complex I (COPI), a Golgi-associated complex with an emerging role in endosomal dynamics. Using proximity ligation assays, we validated the interaction between Vac14 and COPI subunit COPB1 and between Vac14 and Arf1, a GTPase required for COPI assembly. In summary, this study used BioID to comprehensively map the Vac14-Fig4 interactome, revealing potential roles for these proteins in diverse cellular processes and pathways, including preliminary evidence of an interaction between Vac14 and COPI. Data are available via ProteomeXchange with the identifier PXD027917.
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Affiliation(s)
- Shirley Qiu
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa K1H 8M5, Canada.,Ottawa Institute of Systems Biology, University of Ottawa, Ottawa K1H 8M5, Canada.,Centre for Infection, Immunity, and Inflammation, University of Ottawa, Ottawa K1H 8M5, Canada
| | - Mathieu Lavallée-Adam
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa K1H 8M5, Canada.,Ottawa Institute of Systems Biology, University of Ottawa, Ottawa K1H 8M5, Canada
| | - Marceline Côté
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa K1H 8M5, Canada.,Ottawa Institute of Systems Biology, University of Ottawa, Ottawa K1H 8M5, Canada.,Centre for Infection, Immunity, and Inflammation, University of Ottawa, Ottawa K1H 8M5, Canada
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19
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Cinato M, Guitou L, Saidi A, Timotin A, Sperazza E, Duparc T, Zolov SN, Giridharan SSP, Weisman LS, Martinez LO, Roncalli J, Kunduzova O, Tronchere H, Boal F. Apilimod alters TGFβ signaling pathway and prevents cardiac fibrotic remodeling. Theranostics 2021; 11:6491-6506. [PMID: 33995670 PMCID: PMC8120213 DOI: 10.7150/thno.55821] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 04/02/2021] [Indexed: 01/09/2023] Open
Abstract
Rationale: TGFβ signaling pathway controls tissue fibrotic remodeling, a hallmark in many diseases leading to organ injury and failure. In this study, we address the role of Apilimod, a pharmacological inhibitor of the lipid kinase PIKfyve, in the regulation of cardiac pathological fibrotic remodeling and TGFβ signaling pathway. Methods: The effects of Apilimod treatment on myocardial fibrosis, hypertrophy and cardiac function were assessed in vivo in a mouse model of pressure overload-induced heart failure. Primary cardiac fibroblasts and HeLa cells treated with Apilimod as well as genetic mutation of PIKfyve in mouse embryonic fibroblasts were used as cell models. Results: When administered in vivo, Apilimod reduced myocardial interstitial fibrosis development and prevented left ventricular dysfunction. In vitro, Apilimod controlled TGFβ-dependent activation of primary murine cardiac fibroblasts. Mechanistically, both Apilimod and genetic mutation of PIKfyve induced TGFβ receptor blockade in intracellular vesicles, negatively modulating its downstream signaling pathway and ultimately dampening TGFβ response. Conclusions: Altogether, our findings propose a novel function for PIKfyve in the control of myocardial fibrotic remodeling and the TGFβ signaling pathway, therefore opening the way to new therapeutic perspectives to prevent adverse fibrotic remodeling using Apilimod treatment.
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Affiliation(s)
- Mathieu Cinato
- INSERM U1297 I2MC, Toulouse, France and Université Paul Sabatier, Toulouse, France
| | - Laurie Guitou
- INSERM U1297 I2MC, Toulouse, France and Université Paul Sabatier, Toulouse, France
| | - Amira Saidi
- INSERM U1297 I2MC, Toulouse, France and Université Paul Sabatier, Toulouse, France
| | - Andrei Timotin
- INSERM U1297 I2MC, Toulouse, France and Université Paul Sabatier, Toulouse, France
| | - Erwan Sperazza
- INSERM U1297 I2MC, Toulouse, France and Université Paul Sabatier, Toulouse, France
| | - Thibaut Duparc
- INSERM U1297 I2MC, Toulouse, France and Université Paul Sabatier, Toulouse, France
| | - Sergey N. Zolov
- Life Sciences Institute, University of Michigan, Ann Arbor, USA
| | | | - Lois S. Weisman
- Life Sciences Institute, University of Michigan, Ann Arbor, USA
| | - Laurent O. Martinez
- INSERM U1297 I2MC, Toulouse, France and Université Paul Sabatier, Toulouse, France
| | - Jerome Roncalli
- INSERM U1297 I2MC, Toulouse, France and Université Paul Sabatier, Toulouse, France
- Department of Cardiology, Toulouse University Hospital, Toulouse, France
| | - Oksana Kunduzova
- INSERM U1297 I2MC, Toulouse, France and Université Paul Sabatier, Toulouse, France
| | - Helene Tronchere
- INSERM U1297 I2MC, Toulouse, France and Université Paul Sabatier, Toulouse, France
| | - Frederic Boal
- INSERM U1297 I2MC, Toulouse, France and Université Paul Sabatier, Toulouse, France
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20
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Ernest James Phillips T, Maguire E. Phosphoinositides: Roles in the Development of Microglial-Mediated Neuroinflammation and Neurodegeneration. Front Cell Neurosci 2021; 15:652593. [PMID: 33841102 PMCID: PMC8032904 DOI: 10.3389/fncel.2021.652593] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/08/2021] [Indexed: 12/11/2022] Open
Abstract
Microglia are increasingly recognized as vital players in the pathology of a variety of neurodegenerative conditions including Alzheimer’s (AD) and Parkinson’s (PD) disease. While microglia have a protective role in the brain, their dysfunction can lead to neuroinflammation and contributes to disease progression. Also, a growing body of literature highlights the seven phosphoinositides, or PIPs, as key players in the regulation of microglial-mediated neuroinflammation. These small signaling lipids are phosphorylated derivates of phosphatidylinositol, are enriched in the brain, and have well-established roles in both homeostasis and disease.Disrupted PIP levels and signaling has been detected in a variety of dementias. Moreover, many known AD disease modifiers identified via genetic studies are expressed in microglia and are involved in phospholipid metabolism. One of these, the enzyme PLCγ2 that hydrolyzes the PIP species PI(4,5)P2, displays altered expression in AD and PD and is currently being investigated as a potential therapeutic target.Perhaps unsurprisingly, neurodegenerative conditions exhibiting PIP dyshomeostasis also tend to show alterations in aspects of microglial function regulated by these lipids. In particular, phosphoinositides regulate the activities of proteins and enzymes required for endocytosis, toll-like receptor signaling, purinergic signaling, chemotaxis, and migration, all of which are affected in a variety of neurodegenerative conditions. These functions are crucial to allow microglia to adequately survey the brain and respond appropriately to invading pathogens and other abnormalities, including misfolded proteins. AD and PD therapies are being developed to target many of the above pathways, and although not yet investigated, simultaneous PIP manipulation might enhance the beneficial effects observed. Currently, only limited therapeutics are available for dementia, and although these show some benefits for symptom severity and progression, they are far from curative. Given the importance of microglia and PIPs in dementia development, this review summarizes current research and asks whether we can exploit this information to design more targeted, or perhaps combined, dementia therapeutics. More work is needed to fully characterize the pathways discussed in this review, but given the strength of the current literature, insights in this area could be invaluable for the future of neurodegenerative disease research.
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Affiliation(s)
| | - Emily Maguire
- UK Dementia Research Institute at Cardiff University, Cardiff, United Kingdom
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21
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Iuliano M, Seeley C, Sapp E, Jones EL, Martin C, Li X, DiFiglia M, Kegel-Gleason KB. Disposition of Proteins and Lipids in Synaptic Membrane Compartments Is Altered in Q175/Q7 Huntington's Disease Mouse Striatum. Front Synaptic Neurosci 2021; 13:618391. [PMID: 33815086 PMCID: PMC8013775 DOI: 10.3389/fnsyn.2021.618391] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 02/24/2021] [Indexed: 12/14/2022] Open
Abstract
Dysfunction at synapses is thought to be an early change contributing to cognitive, psychiatric and motor disturbances in Huntington's disease (HD). In neurons, mutant Huntingtin collects in aggregates and distributes to the same sites as wild-type Huntingtin including on membranes and in synapses. In this study, we investigated the biochemical integrity of synapses in HD mouse striatum. We performed subcellular fractionation of striatal tissue from 2 and 6-month old knock-in Q175/Q7 HD and Q7/Q7 mice. Compared to striata of Q7/Q7 mice, proteins including GLUT3, Na+/K+ ATPase, NMDAR 2b, PSD95, and VGLUT1 had altered distribution in Q175/Q7 HD striata of 6-month old mice but not 2-month old mice. These proteins are found on plasma membranes and pre- and postsynaptic membranes supporting hypotheses that functional changes at synapses contribute to cognitive and behavioral symptoms of HD. Lipidomic analysis of mouse fractions indicated that compared to those of wild-type, fractions 1 and 2 of 6 months Q175/Q7 HD had altered levels of two species of PIP2, a phospholipid involved in synaptic signaling, increased levels of cholesterol ester and decreased cardiolipin species. At 2 months, increased levels of species of acylcarnitine, phosphatidic acid and sphingomyelin were measured. EM analysis showed that the contents of fractions 1 and 2 of Q7/Q7 and Q175/Q7 HD striata had a mix of isolated synaptic vesicles, vesicle filled axon terminals singly or in clusters, and ER and endosome-like membranes. However, those of Q175/Q7 striata contained significantly fewer and larger clumps of particles compared to those of Q7/Q7. Human HD postmortem putamen showed differences from control putamen in subcellular distribution of two proteins (Calnexin and GLUT3). Our biochemical, lipidomic and EM analysis show that the presence of the HD mutation conferred age dependent disruption of localization of synaptic proteins and lipids important for synaptic function. Our data demonstrate concrete biochemical changes suggesting altered integrity of synaptic compartments in HD mice that may mirror changes in HD patients and presage cognitive and psychiatric changes that occur in premanifest HD.
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22
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DoĞan E, DÜzgÜn Z, Yildirim Z, Özdİl B, AktuĞ H, Bozok ÇetİntaŞ V. The effects of PIKfyve inhibitor YM201636 on claudins and malignancy potential of nonsmall cell cancer cells. ACTA ACUST UNITED AC 2021; 45:26-34. [PMID: 33597819 PMCID: PMC7877718 DOI: 10.3906/biy-2010-32] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/22/2020] [Indexed: 11/15/2022]
Abstract
PIKfyve is an evolutionarily conserved lipid and protein kinase enzyme that has pleiotropic cellular functions. The aim of the present study was to investigate the effects of phosphatidylinositol-3-phosphate 5-kinase (PIKfyve) inhibitor, YM201636, on nonsmall cell lung cancer (NSCLC) cells growth, tumorigenicity, and claudin (CLDN) expressions. Three NSCLC cell lines (Calu-1, H1299 and HCC827) were used to compare the effects of YM201636. Cytotoxic effects of YM201636 were analysed using XTT assay. Malignancy potential of cells assesses with wound healing and soft agar colony-forming assays. mRNA and protein expressions of claudins were analysed by qRT-PCR and immunofluorescence staining. Our results revealed that YM201636 inhibited the proliferation and malignancy potential of Calu-1, H1299, and HCC827 cells in a dose-dependent manner. After YM201636 treatment CLDN1, -3 and -5 expressions increased significantly in HCC827 cells. CLDN3 and -5 expressions also significantly increased in Calu1 cell line. YM201636 treatment significantly reduced the CLDN1 and increased the CLDN5 expression in H1299 cells. Immunofluorescence staining of CLDN1, -3 and -5 proteins showed a significant increase after YM201636 treatment. Besides, YM201636 induced EGFR mRNA expression in all NSCLC cell lines. Our results have shown that YM201636 inhibits tumorigenicity of NSCLC cells. Furthermore, estimated glomerular filtration rate (EGFR) pathway is important signalling involved in the regulation of claudins. Understanding the mechanisms of PIKfyve inhibitors may improve cancer treatment particularly for EGFR overactivated NSCLC.
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Affiliation(s)
- Eda DoĞan
- Department of Medical Biology, Faculty of Medicine, Ege University, İzmir Turkey
| | - Zekeriya DÜzgÜn
- Department of Medical Biology, Faculty of Medicine, Giresun University, Giresun Turkey
| | - Zafer Yildirim
- Department of Medical Biology, Faculty of Medicine, Ege University, İzmir Turkey
| | - Berrin Özdİl
- Department of Histology and Embryology, Faculty of Medicine, Ege University, İzmir Turkey
| | - Hüseyin AktuĞ
- Department of Histology and Embryology, Faculty of Medicine, Ege University, İzmir Turkey
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23
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Steinfeld N, Giridharan SSP, Kauffman EJ, Weisman LS. Simultaneous Detection of Phosphoinositide Lipids by Radioactive Metabolic Labeling. Methods Mol Biol 2021; 2251:1-17. [PMID: 33481228 PMCID: PMC8059495 DOI: 10.1007/978-1-0716-1142-5_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
Phosphoinositide (PPI) lipids are a crucial class of low-abundance signaling molecules that regulate many processes within cells. Methods that enable simultaneous detection of all PPI lipid species provide a wholistic snapshot of the PPI profile of cells, which is critical for probing PPI biology. Here we describe a method for the simultaneous measurement of cellular PPI levels by metabolically labeling yeast or mammalian cells with myo-3H-inositol, extracting radiolabeled glycerophosphoinositides, and separating lipid species on an anion exchange column via HPLC.
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Affiliation(s)
- Noah Steinfeld
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI, USA
| | | | - Emily J Kauffman
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Lois S Weisman
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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24
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Yang M, Zhu Z, Bai Y, Zhuang Z, Ge F, Li M, Wang S. A novel phosphoinositide kinase Fab1 regulates biosynthesis of pathogenic aflatoxin in Aspergillus flavus. Virulence 2020; 12:96-113. [PMID: 33315533 PMCID: PMC7781676 DOI: 10.1080/21505594.2020.1859820] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Aspergillus flavus (A. flavus) is one of the most important model environmental fungi which can produce a potent toxin and carcinogen known as aflatoxin. Aflatoxin contamination causes massive agricultural economic loss and a critical human health issue each year. Although a functional vacuole has been highlighted for its fundamental importance in fungal virulence, the molecular mechanisms of the vacuole in regulating the virulence of A. flavus remain largely unknown. Here, we identified a novel vacuole-related protein in A. flavus, the ortholog of phosphatidylinositol-3-phosphate-5-kinase (Fab1) in Saccharomyces cerevisiae. This kinase was located at the vacuolar membrane, and loss of fab1 function was found to affect the growth, conidia and sclerotial development, cellular acidification and metal ion homeostasis, aflatoxin production and pathogenicity of A. flavus. Further functional analysis revealed that Fab1 was required to maintain the vacuole size and cell morphology. Additional quantitative proteomic analysis suggested that Fab1 was likely to play an important role in maintaining vacuolar/cellular homeostasis, with vacuolar dysregulation upon fab1 deletion leading to impaired aflatoxin synthesis in this fungus. Together, these results provide insight into the molecular mechanisms by which this pathogen produces aflatoxin and mediates its pathogenicity, and may facilitate dissection of the vacuole-mediated regulatory network in A. flavus.
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Affiliation(s)
- Mingkun Yang
- School of Life Sciences, and Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Fujian Agriculture and Forestry University , Fuzhou, China.,State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan, China
| | - Zhuo Zhu
- School of Life Sciences, and Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Fujian Agriculture and Forestry University , Fuzhou, China
| | - Youhuang Bai
- School of Life Sciences, and Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Fujian Agriculture and Forestry University , Fuzhou, China
| | - Zhenhong Zhuang
- School of Life Sciences, and Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Fujian Agriculture and Forestry University , Fuzhou, China
| | - Feng Ge
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan, China
| | - Mingzhu Li
- School of Life Sciences, and Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Fujian Agriculture and Forestry University , Fuzhou, China
| | - Shihua Wang
- School of Life Sciences, and Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Fujian Agriculture and Forestry University , Fuzhou, China
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25
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Palamiuc L, Ravi A, Emerling BM. Phosphoinositides in autophagy: current roles and future insights. FEBS J 2019; 287:222-238. [DOI: 10.1111/febs.15127] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/27/2019] [Accepted: 11/05/2019] [Indexed: 12/22/2022]
Affiliation(s)
- Lavinia Palamiuc
- Sanford Burnham Prebys Medical Discovery Institute Cancer Metabolism and Signaling Networks Program La JollaCA USA
| | - Archna Ravi
- Sanford Burnham Prebys Medical Discovery Institute Cancer Metabolism and Signaling Networks Program La JollaCA USA
| | - Brooke M. Emerling
- Sanford Burnham Prebys Medical Discovery Institute Cancer Metabolism and Signaling Networks Program La JollaCA USA
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26
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Raghu P, Joseph A, Krishnan H, Singh P, Saha S. Phosphoinositides: Regulators of Nervous System Function in Health and Disease. Front Mol Neurosci 2019; 12:208. [PMID: 31507376 PMCID: PMC6716428 DOI: 10.3389/fnmol.2019.00208] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 08/07/2019] [Indexed: 12/11/2022] Open
Abstract
Phosphoinositides, the seven phosphorylated derivatives of phosphatidylinositol have emerged as regulators of key sub-cellular processes such as membrane transport, cytoskeletal function and plasma membrane signaling in eukaryotic cells. All of these processes are also present in the cells that constitute the nervous system of animals and in this setting too, these are likely to tune key aspects of cell biology in relation to the unique structure and function of neurons. Phosphoinositides metabolism and function are mediated by enzymes and proteins that are conserved in evolution, and analysis of knockouts of these in animal models implicate this signaling system in neural function. Most recently, with the advent of human genome analysis, mutations in genes encoding components of the phosphoinositide signaling pathway have been implicated in human diseases although the cell biological basis of disease phenotypes in many cases remains unclear. In this review we evaluate existing evidence for the involvement of phosphoinositide signaling in human nervous system diseases and discuss ways of enhancing our understanding of the role of this pathway in the human nervous system's function in health and disease.
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Affiliation(s)
- Padinjat Raghu
- National Centre for Biological Sciences-TIFR, Bengaluru, India
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27
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Abstract
Polyphosphoinositides (PPIn) are essential signaling phospholipids that make remarkable contributions to the identity of all cellular membranes and signaling cascades in mammalian cells. They exert regulatory control over membrane homeostasis via selective interactions with cellular proteins at the membrane–cytoplasm interface. This review article briefly summarizes our current understanding of the key roles that PPIn play in orchestrating and regulating crucial electrical and chemical signaling events in mammalian neurons and the significant neuro-pathophysiological conditions that arise following alterations in their metabolism.
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Affiliation(s)
- Eamonn James Dickson
- Department Physiology and Membrane Biology, University of California, Davis, CA, 95616, USA
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28
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Parkinson GT, Hanley JG. Mechanisms of AMPA Receptor Endosomal Sorting. Front Mol Neurosci 2018; 11:440. [PMID: 30568574 PMCID: PMC6289981 DOI: 10.3389/fnmol.2018.00440] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/13/2018] [Indexed: 12/21/2022] Open
Abstract
The regulation of synaptic AMPA receptors (AMPARs) is critical for excitatory synaptic transmission, synaptic plasticity and the consequent formation of neural circuits during brain development and their modification during learning and memory processes. The number of synaptic AMPARs is regulated through endocytosis, exocytosis and endosomal sorting that results in recycling back to the plasma membrane or degradation in the lysosome. Hence, endo-lysosomal sorting is vitally important in maintaining AMPAR expression at the synapse, and the dynamic regulation of these trafficking events is a key component of synaptic plasticity. A reduction in synaptic strength such as in long-term depression (LTD) involves AMPAR sorting to lysosomes to reduce synaptic AMPAR number, whereas long-term potentiation (LTP) involves an increase in AMPAR recycling to increase the number of AMPARs at synapses. Here, we review our current understanding of the endosomal trafficking routes taken by AMPARs, and the mechanisms involved in AMPAR endosomal sorting, focussing on the numerous AMPAR associated proteins that have been implicated in this complex process. We also discuss how these events are dysregulated in brain disorders.
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Affiliation(s)
- Gabrielle T Parkinson
- Centre for Synaptic Plasticity and School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Jonathan G Hanley
- Centre for Synaptic Plasticity and School of Biochemistry, University of Bristol, Bristol, United Kingdom
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29
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Abstract
The lysosome-like vacuole is the main organelle to degrade membrane proteins and organelles and, thus, provides amino acids, but also ions to the cytosol for cellular survival. Maintenance of vacuole membrane integrity is thus important for cellular adaptations. The vacuole contains several protein complexes on its surface to maintain the vacuole functional, and one such complex is a lipid kinase named Fab1 (of PIKfyve in human cells). Fab1 is part of a protein complex that produces a phosphorylated lipid, PI-3,5-P2. Other proteins bind PI-3,5-P2 and can fragment the vacuole to balance volume vs. membrane during stress. We now identify Ivy1 as a protein that binds Fab1 and controls its activity. Lysosomes have an important role in cellular protein and organelle quality control, metabolism, and signaling. On the surface of lysosomes, the PIKfyve/Fab1 complex generates phosphatidylinositol 3,5-bisphosphate, PI-3,5-P2, which is critical for lysosomal membrane homeostasis during acute osmotic stress and for lysosomal signaling. Here, we identify the inverted BAR protein Ivy1 as an inhibitor of the Fab1 complex with a direct influence on PI-3,5-P2 levels and vacuole homeostasis. Ivy1 requires Ypt7 binding for its function, binds PI-3,5-P2, and interacts with the Fab1 kinase. Colocalization of Ivy1 and Fab1 is lost during osmotic stress. In agreement with Ivy1’s role as a Fab1 regulator, its overexpression blocks Fab1 activity during osmotic shock and vacuole fragmentation. Conversely, loss of Ivy1, or lateral relocalization of Ivy1 on vacuoles away from Fab1, results in vacuole fragmentation and poor growth. Our data suggest that Ivy1 modulates Fab1-mediated PI-3,5-P2 synthesis during membrane stress and may allow adjustment of the vacuole membrane environment.
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30
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Narayanan P, Hütte M, Kudryasheva G, Taberner FJ, Lechner SG, Rehfeldt F, Gomez-Varela D, Schmidt M. Myotubularin related protein-2 and its phospholipid substrate PIP 2 control Piezo2-mediated mechanotransduction in peripheral sensory neurons. eLife 2018. [PMID: 29521261 PMCID: PMC5898911 DOI: 10.7554/elife.32346] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Piezo2 ion channels are critical determinants of the sense of light touch in vertebrates. Yet, their regulation is only incompletely understood. We recently identified myotubularin related protein-2 (Mtmr2), a phosphoinositide (PI) phosphatase, in the native Piezo2 interactome of murine dorsal root ganglia (DRG). Here, we demonstrate that Mtmr2 attenuates Piezo2-mediated rapidly adapting mechanically activated (RA-MA) currents. Interestingly, heterologous Piezo1 and other known MA current subtypes in DRG appeared largely unaffected by Mtmr2. Experiments with catalytically inactive Mtmr2, pharmacological blockers of PI(3,5)P2 synthesis, and osmotic stress suggest that Mtmr2-dependent Piezo2 inhibition involves depletion of PI(3,5)P2. Further, we identified a PI(3,5)P2 binding region in Piezo2, but not Piezo1, that confers sensitivity to Mtmr2 as indicated by functional analysis of a domain-swapped Piezo2 mutant. Altogether, our results propose local PI(3,5)P2 modulation via Mtmr2 in the vicinity of Piezo2 as a novel mechanism to dynamically control Piezo2-dependent mechanotransduction in peripheral sensory neurons. We often take our sense of touch for granted. Yet, our every-day life greatly depends on the ability to perceive our environment to alert us of danger or to further social interactions, such as mother-child bonding. Our sense of touch relies on the conversion of mechanical stimuli to electrical signals (this is known as mechanotransduction), which then travel to brain to be processed. This task is fulfilled by specific ion channels called Piezo2, which are activated when cells are exposed to pressure and other mechanical forces. These channels can be found in sensory nerves and specialized structures in the skin, where they help to detect physical contact, roughness of surfaces and the position of our body parts. It is still not clear how Piezo2 channels are regulated but previous research by several laboratories suggests that they work in conjunction with other proteins. One of these proteins is the myotubularin related protein-2, or Mtmr2 for short. Now, Narayanan et al. – including some of the researchers involved in the previous research – set out to advance our understanding of the molecular basis of touch and looked more closely at Mtmr2. To test if Mtmr2 played a role in mechanotransduction, Narayanan et al. both increased and reduced the levels of this protein in sensory neurons of mice grown in the laboratory. When Mtmr2 levels were low, the activity of Piezo2 channels increased. However, when the protein levels were high, Piezo2 channels were inhibited. These results suggest that Mtmr2 can control the activity of Piezo2. Further experiments, in which Mtmr2 was genetically modified or sensory neurons were treated with chemicals, revealed that Mtmr2 reduces a specific fatty acid in the membrane of nerve cells, which in turn attenuates the activity of Piezo2. This study identified Mtmr2 and distinct fatty acids in the cell membrane as new components of the complex setup required for the sense of touch. A next step will be to test if these molecules also influence the activity of Piezo2 when the skin has become injured or upon inflammation.
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Affiliation(s)
- Pratibha Narayanan
- Emmy Noether-Group Somatosensory Signaling and Systems Biology, Max Planck Institute for Experimental Medicine, Goettingen, Germany
| | - Meike Hütte
- Emmy Noether-Group Somatosensory Signaling and Systems Biology, Max Planck Institute for Experimental Medicine, Goettingen, Germany
| | - Galina Kudryasheva
- Third Institute of Physics - Biophysics, University of Goettingen, Goettingen, Germany
| | | | | | - Florian Rehfeldt
- Third Institute of Physics - Biophysics, University of Goettingen, Goettingen, Germany
| | - David Gomez-Varela
- Emmy Noether-Group Somatosensory Signaling and Systems Biology, Max Planck Institute for Experimental Medicine, Goettingen, Germany
| | - Manuela Schmidt
- Emmy Noether-Group Somatosensory Signaling and Systems Biology, Max Planck Institute for Experimental Medicine, Goettingen, Germany
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31
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Liu Q, Sun NN, Wu ZZ, Fan DH, Cao MQ. Chaihu-Shugan-San exerts an antidepressive effect by downregulating miR-124 and releasing inhibition of the MAPK14 and Gria3 signaling pathways. Neural Regen Res 2018; 13:837-845. [PMID: 29863014 PMCID: PMC5998613 DOI: 10.4103/1673-5374.232478] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Dysregulation of miR-124 has been reported to be involved in the pathophysiology of depression. Chaihu-Shugan-San, a traditional Chinese medicine, has antidepressive activity; however, the underlying mechanisms remain unclear. In this study, to generate a rodent model of depression, rats were subjected to a combination of solitary confinement and chronic unpredictable mild stress for 28 days. Rats were intragastrically administered Chaihu-Shugan-San (2.835 mL/kg/d) for 4 weeks, once a day. Real-time reverse-transcription quantitative polymerase chain reaction, miRNA microarray, western blot assay and transmission electron microscopy demonstrated that Chaihu-Shugan-San downregulated miR-124 expression and upregulated the mRNA and protein levels of mitogen-activated protein kinase 14 (MAPK14) and glutamate receptor subunit 3 (Gria3). Chaihu-Shugan-San also promoted synapse formation in the hippocampus. The open field test, sucrose consumption test and forced swimming test were used to assess depression-like behavior. After intragastric administration of Chaihu-Shugan-San, sucrose consumption increased, while the depressive behaviors were substantially reduced. Together, these findings suggest that Chaihu-Shugan-San exerts an antidepressant-like effect by downregulating miR-124 expression and by releasing the inhibition of the MAPK14 and Gria3 signaling pathways.
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Affiliation(s)
- Qiong Liu
- Department of Cardiovascular Medicine, XiangYa Hospital of Central South University, Changsha, Hunan Province, China
| | - Ning-Ning Sun
- Shenzhen Institute of Geriatrics, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen, Guangdong Province, China
| | - Zheng-Zhi Wu
- Shenzhen Institute of Geriatrics, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen, Guangdong Province, China
| | - Da-Hua Fan
- The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen; Chinese and Wsetern Integrative Medicine, Shcool of Medicine, Jinan University, Guangzhou, Guangdong Province, China
| | - Mei-Qun Cao
- Shenzhen Institute of Geriatrics, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen, Guangdong Province, China
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32
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Al-Ramahi I, Giridharan SSP, Chen YC, Patnaik S, Safren N, Hasegawa J, de Haro M, Wagner Gee AK, Titus SA, Jeong H, Clarke J, Krainc D, Zheng W, Irvine RF, Barmada S, Ferrer M, Southall N, Weisman LS, Botas J, Marugan JJ. Inhibition of PIP4Kγ ameliorates the pathological effects of mutant huntingtin protein. eLife 2017; 6:29123. [PMID: 29256861 PMCID: PMC5743427 DOI: 10.7554/elife.29123] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 11/13/2017] [Indexed: 12/15/2022] Open
Abstract
The discovery of the causative gene for Huntington’s disease (HD) has promoted numerous efforts to uncover cellular pathways that lower levels of mutant huntingtin protein (mHtt) and potentially forestall the appearance of HD-related neurological defects. Using a cell-based model of pathogenic huntingtin expression, we identified a class of compounds that protect cells through selective inhibition of a lipid kinase, PIP4Kγ. Pharmacological inhibition or knock-down of PIP4Kγ modulates the equilibrium between phosphatidylinositide (PI) species within the cell and increases basal autophagy, reducing the total amount of mHtt protein in human patient fibroblasts and aggregates in neurons. In two Drosophila models of Huntington’s disease, genetic knockdown of PIP4K ameliorated neuronal dysfunction and degeneration as assessed using motor performance and retinal degeneration assays respectively. Together, these results suggest that PIP4Kγ is a druggable target whose inhibition enhances productive autophagy and mHtt proteolysis, revealing a useful pharmacological point of intervention for the treatment of Huntington’s disease, and potentially for other neurodegenerative disorders.
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Affiliation(s)
- Ismael Al-Ramahi
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Baylor College of Medicine, Texas Medical Center, Houston, United States
| | | | - Yu-Chi Chen
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Samarjit Patnaik
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Nathaniel Safren
- Department of Neurology, University of Michigan, Ann Arbor, United States
| | - Junya Hasegawa
- Department of Cell and Developmental Biology, Life Sciences Institute, University of Michigan, Ann Arbor, United States
| | - Maria de Haro
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Baylor College of Medicine, Texas Medical Center, Houston, United States
| | - Amanda K Wagner Gee
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Steven A Titus
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Hyunkyung Jeong
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Jonathan Clarke
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Dimitri Krainc
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Wei Zheng
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Robin F Irvine
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Sami Barmada
- Department of Neurology, University of Michigan, Ann Arbor, United States
| | - Marc Ferrer
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Noel Southall
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Lois S Weisman
- Department of Cell and Developmental Biology, Life Sciences Institute, University of Michigan, Ann Arbor, United States
| | - Juan Botas
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Baylor College of Medicine, Texas Medical Center, Houston, United States
| | - Juan Jose Marugan
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
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33
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Hirano T, Stecker K, Munnik T, Xu H, Sato MH. Visualization of Phosphatidylinositol 3,5-Bisphosphate Dynamics by a Tandem ML1N-Based Fluorescent Protein Probe in Arabidopsis. PLANT & CELL PHYSIOLOGY 2017; 58:1185-1195. [PMID: 28158631 PMCID: PMC5921506 DOI: 10.1093/pcp/pcx011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Accepted: 01/13/2017] [Indexed: 05/24/2023]
Abstract
Phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2] is a low-abundance phospholipid known to be associated with a wide variety of physiological functions in plants. However, the localization and dynamics of PI(3,5)P2 in plant cells remain largely unknown, partially due to the lack of an effective fluorescent probe. Using Arabidopsis transgenic plant expressing the PI(3,5)P2-labeling fluorescent probe (tagRFP-ML1N*2) developed based on a tandem repeat of the cytosolic phosphoinositide-interacting domain (ML1N) of the mammalian lysosomal transient receptor potential cation channel, Mucolipin 1 (TRPML1), here we show that PI(3,5)P2 is predominantly localized on the limited membranes of the FAB1- and SNX1-positive late endosomes, but rarely localized on the membranes of plant vacuoles or trans-Golgi network/early endosomes of cortical cells of the root differentiation zone. The late endosomal localization of tagRFP-ML1N*2 is reduced or abolished by pharmacological inhibition or genetic knockdown of expression of genes encoding PI(3,5)P2-synthesizing enzymes, FAB1A/B, but markedly increased with FAB1A overexpression. Notably, reactive oxygen species (ROS) significantly increase late endosomal levels of PI(3,5)P2. Thus, tandem ML1N-based PI(3,5)P2 probes can reliably monitor intracellular dynamics of PI(3,5)P2 in Arabidopsis cells with less binding activity to other endomembrane organelles.
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Affiliation(s)
- Tomoko Hirano
- Laboratory of Cellular Dynamics, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamo-nakaragi-cho, Sakyo-ku, Kyoto, 606-8522 Japan
| | - Kelly Stecker
- Biotechnology Center, University of Wisconsin, Madison, WI 53706, USA
| | - Teun Munnik
- Section of Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Science park 904, 1098 XH Amsterdam 94216, The Netherlands
| | - Haoxing Xu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Masa H. Sato
- Laboratory of Cellular Dynamics, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamo-nakaragi-cho, Sakyo-ku, Kyoto, 606-8522 Japan
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34
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Jin N, Jin Y, Weisman LS. Early protection to stress mediated by CDK-dependent PI3,5P 2 signaling from the vacuole/lysosome. J Cell Biol 2017. [PMID: 28637746 PMCID: PMC5496620 DOI: 10.1083/jcb.201611144] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Adaptation to stress is a critical strategy for all life. Known strategies involve signaling pathways that induce changes in gene expression. These changes take time and cannot protect against acute assaults. Jin et al. reveal an early stress protection pathway regulated by the vacuole/lysosome. Adaptation to environmental stress is critical for cell survival. Adaptation generally occurs via changes in transcription and translation. However, there is a time lag before changes in gene expression, which suggests that more rapid mechanisms likely exist. In this study, we show that in yeast, the cyclin-dependent kinase Pho85/CDK5 provides protection against hyperosmotic stress and acts before long-term adaptation provided by Hog1. This protection requires the vacuolar/endolysosomal signaling lipid PI3,5P2. We show that Pho85/CDK5 directly phosphorylates and positively regulates the PI3P-5 kinase Fab1/PIKfyve complex and provide evidence that this regulation is conserved in mammalian cells. Moreover, this regulation is particularly crucial in yeast for the stress-induced transient elevation of PI3,5P2. Our study reveals a rapid protection mechanism regulated by Pho85/CDK5 via signaling from the vacuole/lysosome, which is distinct temporally and spatially from the previously discovered long-term adaptation Hog1 pathway, which signals from the nucleus.
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Affiliation(s)
- Natsuko Jin
- Life Sciences Institute, University of Michigan, Ann Arbor, MI
| | - Yui Jin
- Life Sciences Institute, University of Michigan, Ann Arbor, MI
| | - Lois S Weisman
- Life Sciences Institute, University of Michigan, Ann Arbor, MI .,Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI
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35
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Kawasaki T, Ito K, Miyata H, Akira S, Kawai T. Deletion of PIKfyve alters alveolar macrophage populations and exacerbates allergic inflammation in mice. EMBO J 2017; 36:1707-1718. [PMID: 28533230 DOI: 10.15252/embj.201695528] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 03/14/2017] [Accepted: 04/07/2017] [Indexed: 11/09/2022] Open
Abstract
Alveolar macrophages (AMs) are specialized tissue-resident macrophages that orchestrate the immune responses to inhaled pathogens and maintain organ homeostasis of the lung. Dysregulation of AMs is associated with allergic inflammation and asthma. Here, we examined the role of a phosphoinositide kinase PIKfyve in AM development and function. Mice with conditionally deleted PIKfyve in macrophages have altered AM populations. PIKfyve deficiency results in a loss of AKT activation in response to GM-CSF, a cytokine critical for AM development. Upon exposure to house dust mite extract, mutant mice display severe lung inflammation and allergic asthma accompanied by infiltration of eosinophils and lymphoid cells. Moreover, they have defects in production of retinoic acid and fail to support incorporation of Foxp3+ Treg cells in the lung, resulting in exacerbation of lung inflammation. Thus, PIKfyve plays a role in preventing excessive lung inflammation through regulating AM function.
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Affiliation(s)
- Takumi Kawasaki
- Laboratory of Molecular Immunobiology, Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Nara, Japan
| | - Kosuke Ito
- Laboratory of Molecular Immunobiology, Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Nara, Japan
| | - Haruhiko Miyata
- Department of Experimental Genome Research, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Shizuo Akira
- Department of Host Defense, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.,Laboratory of Host Defense, Immunology Frontier Research Center (IFReC), Osaka University, Osaka, Japan
| | - Taro Kawai
- Laboratory of Molecular Immunobiology, Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), Nara, Japan
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36
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Hasegawa J, Strunk BS, Weisman LS. PI5P and PI(3,5)P 2: Minor, but Essential Phosphoinositides. Cell Struct Funct 2017; 42:49-60. [PMID: 28302928 DOI: 10.1247/csf.17003] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In most eukaryotes, phosphoinositides (PIs) have crucial roles in multiple cellular functions. Although the cellular levels of phosphatidylinositol 5-phosphate (PI5P) and phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2) are extremely low relative to some other PIs, emerging evidence demonstrates that both lipids are crucial for the endocytic pathway, intracellular signaling, and adaptation to stress. Mutations that causes defects in the biosynthesis of PI5P and PI(3,5)P2 are linked to human diseases including neurodegenerative disorders. Here, we review recent findings on cellular roles of PI5P and PI(3,5)P2, as well as the pathophysiological importance of these lipids.Key words: Phosphoinositides, Membrane trafficking, Endocytosis, Vacuoles/Lysosomes, Fab1/PIKfyve.
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37
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Epilepsy-associated gene Nedd4-2 mediates neuronal activity and seizure susceptibility through AMPA receptors. PLoS Genet 2017; 13:e1006634. [PMID: 28212375 PMCID: PMC5338825 DOI: 10.1371/journal.pgen.1006634] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 03/06/2017] [Accepted: 02/14/2017] [Indexed: 12/11/2022] Open
Abstract
The neural precursor cell expressed developmentally down-regulated gene 4–2, Nedd4-2, is an epilepsy-associated gene with at least three missense mutations identified in epileptic patients. Nedd4-2 encodes a ubiquitin E3 ligase that has high affinity toward binding and ubiquitinating membrane proteins. It is currently unknown how Nedd4-2 mediates neuronal circuit activity and how its dysfunction leads to seizures or epilepsies. In this study, we provide evidence to show that Nedd4-2 mediates neuronal activity and seizure susceptibility through ubiquitination of GluA1 subunit of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor, (AMPAR). Using a mouse model, termed Nedd4-2andi, in which one of the major forms of Nedd4-2 in the brain is selectively deficient, we found that the spontaneous neuronal activity in Nedd4-2andi cortical neuron cultures, measured by a multiunit extracellular electrophysiology system, was basally elevated, less responsive to AMPAR activation, and much more sensitive to AMPAR blockade when compared with wild-type cultures. When performing kainic acid-induced seizures in vivo, we showed that elevated seizure susceptibility in Nedd4-2andi mice was normalized when GluA1 is genetically reduced. Furthermore, when studying epilepsy-associated missense mutations of Nedd4-2, we found that all three mutations disrupt the ubiquitination of GluA1 and fail to reduce surface GluA1 and spontaneous neuronal activity when compared with wild-type Nedd4-2. Collectively, our data suggest that impaired GluA1 ubiquitination contributes to Nedd4-2-dependent neuronal hyperactivity and seizures. Our findings provide critical information to the future development of therapeutic strategies for patients who carry mutations of Nedd4-2. Many patients with neurological disorders suffer from an imbalance in neuronal and circuit excitability and present with seizure or epilepsy as the common comorbidity. Human genetic studies have identified many epilepsy-associated genes, but the pathways by which those genes are connected to brain circuit excitability are largely unknown. Our study focused on one of the epilepsy-associated genes, Nedd4-2, and aimed to dissect the molecular mechanism underlying Nedd4-2-associated epilepsy. Nedd4-2 encodes a ubiquitin E3 ligase. Several neuronal ion channels have been identified as its substrates, including the GluA1 subunit of AMPAR. Our results first demonstrate up-regulation of spontaneous neuronal activity and seizure susceptibility when Nedd4-2 is reduced in a mouse model. These deficits can be corrected when GluA1/AMPAR is pharmacologically or genetically inhibited. In addition, we found that three epilepsy-associated missense mutations of Nedd4-2 inhibit the ubiquitination of GluA1 and fail to reduce GluA1 surface expression or spontaneous neuronal activity when compared to wild-type Nedd4-2. These findings suggest the reduction of GluA1 ubiquitination as a crucial deficit underlying insufficient function of Nedd4-2 and provide critical information to the development of therapies for patients who carry mutations of Nedd4-2.
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38
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Phosphatidylinositol 3,5-bisphosphate: regulation of cellular events in space and time. Biochem Soc Trans 2016; 44:177-84. [PMID: 26862203 DOI: 10.1042/bst20150174] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Phosphorylated phosphatidylinositol lipids are crucial for most eukaryotes and have diverse cellular functions. The low-abundance signalling lipid phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2] is critical for cellular homoeostasis and adaptation to stimuli. A large complex of proteins that includes the lipid kinase Fab1-PIKfyve, dynamically regulates the levels of PI(3,5)P2. Deficiencies in PI(3,5)P2 are linked to some human diseases, especially those of the nervous system. Future studies will probably determine new, undiscovered regulatory roles of PI(3,5)P2, as well as uncover mechanistic insights into how PI(3,5)P2 contributes to normal human physiology.
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39
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Lenk GM, Szymanska K, Debska-Vielhaber G, Rydzanicz M, Walczak A, Bekiesinska-Figatowska M, Vielhaber S, Hallmann K, Stawinski P, Buehring S, Hsu DA, Kunz WS, Meisler MH, Ploski R. Biallelic Mutations of VAC14 in Pediatric-Onset Neurological Disease. Am J Hum Genet 2016; 99:188-94. [PMID: 27292112 DOI: 10.1016/j.ajhg.2016.05.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 05/02/2016] [Indexed: 01/29/2023] Open
Abstract
In the PI(3,5)P2 biosynthetic complex, the lipid kinase PIKFYVE and the phosphatase FIG4 are bound to the dimeric scaffold protein VAC14, which is composed of multiple heat-repeat domains. Mutations of FIG4 result in the inherited disorders Charcot-Marie-Tooth disease type 4J, Yunis-Varón syndrome, and polymicrogyria with seizures. We here describe inherited variants of VAC14 in two unrelated children with sudden onset of a progressive neurological disorder and regression of developmental milestones. Both children developed impaired movement with dystonia, became nonambulatory and nonverbal, and exhibited striatal abnormalities on MRI. A diagnosis of Leigh syndrome was rejected due to normal lactate profiles. Exome sequencing identified biallelic variants of VAC14 that were inherited from unaffected heterozygous parents in both families. Proband 1 inherited a splice-site variant that results in skipping of exon 13, p.Ile459Profs(∗)4 (not reported in public databases), and the missense variant p.Trp424Leu (reported in the ExAC database in a single heterozygote). Proband 2 inherited two missense variants in the dimerization domain of VAC14, p.Ala582Ser and p.Ser583Leu, that have not been previously reported. Cultured skin fibroblasts exhibited the accumulation of vacuoles that is characteristic of PI(3,5)P2 deficiency. Vacuolization of fibroblasts was rescued by transfection of wild-type VAC14 cDNA. The similar age of onset and neurological decline in the two unrelated children define a recessive disorder resulting from compound heterozygosity for deleterious variants of VAC14.
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Affiliation(s)
- Guy M Lenk
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109-5618, USA
| | - Krystyna Szymanska
- Department of Child Psychiatry, Warsaw Medical University, 02-106 Warsaw, Poland; Department of Experimental and Clinical Neuropathology, Medical Research Center, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | | | - Malgorzata Rydzanicz
- Department of Medical Genetics, Warsaw Medical University, 02-106 Warsaw, Poland
| | - Anna Walczak
- Department of Medical Genetics, Warsaw Medical University, 02-106 Warsaw, Poland
| | | | - Stefan Vielhaber
- Klinik für Neurologie, Universitätsklinikum Magdeburg, 39120 Magdeburg, Germany
| | - Kerstin Hallmann
- Klinik für Epileptologie and Life&Brain Center, Universitätsklinikum Bonn, 53105 Bonn, Germany
| | - Piotr Stawinski
- Department of Medical Genetics, Warsaw Medical University, 02-106 Warsaw, Poland; Institute of Physiology and Pathology of Hearing, 05-830 Nadarzyn, Poland
| | | | - David A Hsu
- Department of Neurology, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Wolfram S Kunz
- Klinik für Epileptologie and Life&Brain Center, Universitätsklinikum Bonn, 53105 Bonn, Germany
| | - Miriam H Meisler
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109-5618, USA.
| | - Rafal Ploski
- Department of Medical Genetics, Warsaw Medical University, 02-106 Warsaw, Poland.
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40
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Gross C. Defective phosphoinositide metabolism in autism. J Neurosci Res 2016; 95:1161-1173. [PMID: 27376697 DOI: 10.1002/jnr.23797] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/26/2016] [Accepted: 06/01/2016] [Indexed: 12/12/2022]
Abstract
Phosphoinositides are essential components of lipid membranes and crucial regulators of many cellular functions, including signal transduction, vesicle trafficking, membrane receptor localization and activity, and determination of membrane identity. These functions depend on the dynamic and highly regulated metabolism of phosphoinositides and require finely balanced activity of specific phosphoinositide kinases and phosphatases. There is increasing evidence from genetic and functional studies that these enzymes are often dysregulated or mutated in autism spectrum disorders; in particular, phosphoinositide 3-kinases and their regulatory subunits appear to be affected frequently. Examples of autism spectrum disorders with defective phosphoinositide metabolism are fragile X syndrome and autism disorders associated with mutations in the phosphoinositide 3-phosphatase tensin homolog deleted on chromosome 10 (PTEN), but recent genetic analyses also suggest that select nonsyndromic, idiopathic forms of autism may have altered activity of phosphoinositide kinases and phosphatases. Isoform-specific inhibitors for some of the phosphoinositide kinases have already been developed for cancer research and treatment, and a few are being evaluated for use in humans. Altogether, this offers exciting opportunities to explore altered phosphoinositide metabolism as a therapeutic target in individuals with certain forms of autism. This review summarizes genetic and functional studies identifying defects in phosphoinositide metabolism in autism and related disorders, describes published preclinical work targeting phosphoinositide 3-kinases in neurological diseases, and discusses the opportunities and challenges ahead to translate these findings from animal models and human cells into clinical application in humans. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Christina Gross
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.,Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio
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41
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Fernández-Monreal M, Sánchez-Castillo C, Esteban JA. APPL1 gates long-term potentiation through its plekstrin homology domain. J Cell Sci 2016; 129:2793-803. [PMID: 27257087 DOI: 10.1242/jcs.183475] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 05/31/2016] [Indexed: 01/02/2023] Open
Abstract
Hippocampal synaptic plasticity involves both membrane trafficking events and intracellular signaling, but how these are coordinated is far from clear. The endosomal transport of glutamate receptors in and out of the postsynaptic membrane responds to multiple signaling cascades triggered by synaptic activity. In this work, we have identified adaptor protein containing a plekstrin homology domain, phosphotyrosine-binding domain and leucine zipper motif 1 (APPL1) as a crucial element linking trafficking and signaling during synaptic plasticity. We show that APPL1 knockdown specifically impairs PI3K-dependent forms of synaptic plasticity, such as long-term potentiation (LTP) and metabotropic-glutamate-receptor-dependent long-term depression (mGluR-LTD). Indeed, we demonstrate that APPL1 is required for the activation of the phosphatidylinositol triphosphate (PIP3) pathway in response to LTP induction. This requirement can be bypassed by membrane localization of PI3K and is related to phosphoinositide binding. Interestingly, inhibitors of PDK1 (also known as PDPK1) and Akt have no effect on LTP expression. Therefore, we conclude that APPL1 gates PI3K activation at the plasma membrane upon LTP induction, which is then relayed by downstream PIP3 effectors that are different from PDK1 and Akt.
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Affiliation(s)
- Mónica Fernández-Monreal
- Centro de Biología Molecular 'Severo Ochoa', Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid (CSIC-UAM), Madrid 28049, Spain
| | - Carla Sánchez-Castillo
- Centro de Biología Molecular 'Severo Ochoa', Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid (CSIC-UAM), Madrid 28049, Spain
| | - José A Esteban
- Centro de Biología Molecular 'Severo Ochoa', Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid (CSIC-UAM), Madrid 28049, Spain
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Currinn H, Guscott B, Balklava Z, Rothnie A, Wassmer T. APP controls the formation of PI(3,5)P(2) vesicles through its binding of the PIKfyve complex. Cell Mol Life Sci 2016; 73:393-408. [PMID: 26216398 PMCID: PMC4706845 DOI: 10.1007/s00018-015-1993-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 06/26/2015] [Accepted: 07/16/2015] [Indexed: 12/05/2022]
Abstract
Phosphoinositides are signalling lipids that are crucial for major signalling events as well as established regulators of membrane trafficking. Control of endosomal sorting and endosomal homeostasis requires phosphatidylinositol-3-phosphate (PI(3)P) and phosphatidylinositol-3,5-bisphosphate (PI(3,5)P2), the latter a lipid of low abundance but significant physiological relevance. PI(3,5)P2 is formed by phosphorylation of PI(3)P by the PIKfyve complex which is crucial for maintaining endosomal homeostasis. Interestingly, loss of PIKfyve function results in dramatic neurodegeneration. Despite the significance of PIKfyve, its regulation is still poorly understood. Here we show that the Amyloid Precursor Protein (APP), a central molecule in Alzheimer's disease, associates with the PIKfyve complex (consisting of Vac14, PIKfyve and Fig4) and that the APP intracellular domain directly binds purified Vac14. We also show that the closely related APP paralogues, APLP1 and 2 associate with the PIKfyve complex. Whether APP family proteins can additionally form direct protein-protein interaction with PIKfyve or Fig4 remains to be explored. We show that APP binding to the PIKfyve complex drives formation of PI(3,5)P2 positive vesicles and that APP gene family members are required for supporting PIKfyve function. Interestingly, the PIKfyve complex is required for APP trafficking, suggesting a feedback loop in which APP, by binding to and stimulating PI(3,5)P2 vesicle formation may control its own trafficking. These data suggest that altered APP processing, as observed in Alzheimer's disease, may disrupt PI(3,5)P2 metabolism, endosomal sorting and homeostasis with important implications for our understanding of the mechanism of neurodegeneration in Alzheimer's disease.
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Affiliation(s)
- Heather Currinn
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK
| | - Benjamin Guscott
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK
| | - Zita Balklava
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK
| | - Alice Rothnie
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK
| | - Thomas Wassmer
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK.
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43
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Lenk GM, Frei CM, Miller AC, Wallen RC, Mironova YA, Giger RJ, Meisler MH. Rescue of neurodegeneration in the Fig4 null mouse by a catalytically inactive FIG4 transgene. Hum Mol Genet 2015; 25:340-7. [PMID: 26604144 DOI: 10.1093/hmg/ddv480] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 11/16/2015] [Indexed: 11/13/2022] Open
Abstract
The lipid phosphatase FIG4 is a subunit of the protein complex that regulates biosynthesis of the signaling lipid PI(3,5)P2. Mutations of FIG4 result in juvenile lethality and spongiform neurodegeneration in the mouse, and are responsible for the human disorders Charcot-Marie-Tooth disease, Yunis-Varon syndrome and polymicrogyria with seizures. We previously demonstrated that conditional expression of a wild-type FIG4 transgene in neurons is sufficient to rescue most of the abnormalities of Fig4 null mice, including juvenile lethality and extensive neurodegeneration. To evaluate the contribution of the phosphatase activity to the in vivo function of Fig4, we introduced the mutation p.Cys486Ser into the Sac phosphatase active-site motif CX5RT. Transfection of the Fig4(Cys486Ser) cDNA into cultured Fig4(-/-) fibroblasts was effective in preventing vacuolization. The neuronal expression of an NSE-Fig4(Cys486Ser) transgene in vivo prevented the neonatal neurodegeneration and juvenile lethality seen in Fig4 null mice. These observations demonstrate that the catalytically inactive FIG4 protein provides significant function, possibly by stabilization of the PI(3,5)P2 biosynthetic complex and/or localization of the complex to endolysosomal vesicles. Despite this partial rescue, later in life the NSE-Fig4(Cys486Ser) transgenic mice display significant abnormalities that include hydrocephalus, defective myelination and reduced lifespan. The late onset phenotype of the NSE-Fig4(Cys486Ser) transgenic mice demonstrates that the phosphatase activity of FIG4 has an essential role in vivo.
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Affiliation(s)
| | | | | | | | | | - Roman J Giger
- Department of Cell and Developmental Biology and Department of Neurology, University of Michigan, 4909 Buhl, Ann Arbor, MI 48109-5618, USA
| | - Miriam H Meisler
- Department of Human Genetics, Department of Neurology, University of Michigan, 4909 Buhl, Ann Arbor, MI 48109-5618, USA
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Phosphoinositide dynamics in the postsynaptic membrane compartment: Mechanisms and experimental approach. Eur J Cell Biol 2015; 94:401-14. [DOI: 10.1016/j.ejcb.2015.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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