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Okreglak V, Ling R, Ingaramo M, Thayer NH, Millett-Sikking A, Gottschling DE. Cell cycle-linked vacuolar pH dynamics regulate amino acid homeostasis and cell growth. Nat Metab 2023; 5:1803-1819. [PMID: 37640943 PMCID: PMC10590757 DOI: 10.1038/s42255-023-00872-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 07/21/2023] [Indexed: 08/31/2023]
Abstract
Amino acid homeostasis is critical for many cellular processes. It is well established that amino acids are compartmentalized using pH gradients generated between organelles and the cytoplasm; however, the dynamics of this partitioning has not been explored. Here we develop a highly sensitive pH reporter and find that the major amino acid storage compartment in Saccharomyces cerevisiae, the lysosome-like vacuole, alkalinizes before cell division and re-acidifies as cells divide. The vacuolar pH dynamics require the uptake of extracellular amino acids and activity of TORC1, the v-ATPase and the cycling of the vacuolar specific lipid phosphatidylinositol 3,5-bisphosphate, which is regulated by the cyclin-dependent kinase Pho85 (CDK5 in mammals). Vacuolar pH regulation enables amino acid sequestration and mobilization from the organelle, which is important for mitochondrial function, ribosome homeostasis and cell size control. Collectively, our data provide a new paradigm for the use of dynamic pH-dependent amino acid compartmentalization during cell growth/division.
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Affiliation(s)
- Voytek Okreglak
- Calico Life Sciences, LLC, South San Francisco, CA, USA.
- Altos Labs, Redwood City, CA, USA.
| | - Rachel Ling
- Calico Life Sciences, LLC, South San Francisco, CA, USA
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2
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Sontag EM, Morales-Polanco F, Chen JH, McDermott G, Dolan PT, Gestaut D, Le Gros MA, Larabell C, Frydman J. Nuclear and cytoplasmic spatial protein quality control is coordinated by nuclear-vacuolar junctions and perinuclear ESCRT. Nat Cell Biol 2023; 25:699-713. [PMID: 37081164 DOI: 10.1038/s41556-023-01128-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 03/14/2023] [Indexed: 04/22/2023]
Abstract
Effective protein quality control (PQC), essential for cellular health, relies on spatial sequestration of misfolded proteins into defined inclusions. Here we reveal the coordination of nuclear and cytoplasmic spatial PQC. Cytoplasmic misfolded proteins concentrate in a cytoplasmic juxtanuclear quality control compartment, while nuclear misfolded proteins sequester into an intranuclear quality control compartment (INQ). Particle tracking reveals that INQ and the juxtanuclear quality control compartment converge to face each other across the nuclear envelope at a site proximal to the nuclear-vacuolar junction marked by perinuclear ESCRT-II/III protein Chm7. Strikingly, convergence at nuclear-vacuolar junction contacts facilitates VPS4-dependent vacuolar clearance of misfolded cytoplasmic and nuclear proteins, the latter entailing extrusion of nuclear INQ into the vacuole. Finding that nuclear-vacuolar contact sites are cellular hubs of spatial PQC to facilitate vacuolar clearance of nuclear and cytoplasmic inclusions highlights the role of cellular architecture in proteostasis maintenance.
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Affiliation(s)
- Emily M Sontag
- Department of Biology, Stanford University, Stanford, CA, USA.
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA.
| | | | - Jian-Hua Chen
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Gerry McDermott
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Patrick T Dolan
- Department of Biology, Stanford University, Stanford, CA, USA
- Quantitative Virology and Evolution Unit, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Daniel Gestaut
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Mark A Le Gros
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Carolyn Larabell
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Judith Frydman
- Department of Biology, Stanford University, Stanford, CA, USA.
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3
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Zhang C, Feng Y, Balutowski A, Miner GE, Rivera-Kohr DA, Hrabak MR, Sullivan KD, Guo A, Calderin JD, Fratti RA. The interdependent transport of yeast vacuole Ca 2+ and H + and the role of phosphatidylinositol 3,5-bisphosphate. J Biol Chem 2022; 298:102672. [PMID: 36334632 PMCID: PMC9706634 DOI: 10.1016/j.jbc.2022.102672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/30/2022] [Accepted: 10/31/2022] [Indexed: 11/27/2022] Open
Abstract
Yeast vacuoles are acidified by the v-type H+-ATPase (V-ATPase) that is comprised of the membrane embedded VO complex and the soluble cytoplasmic V1 complex. The assembly of the V1-VO holoenzyme on the vacuole is stabilized in part through interactions between the VO a-subunit ortholog Vph1 and the lipid phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2). PI(3,5)P2 also affects vacuolar Ca2+ release through the channel Yvc1 and uptake through the Ca2+ pump Pmc1. Here, we asked if H+ and Ca2+ transport activities were connected through PI(3,5)P2. We found that overproduction of PI(3,5)P2 by the hyperactive fab1T2250A mutant augmented vacuole acidification, whereas the kinase-inactive fab1EEE mutant attenuated the formation of a H+ gradient. Separately, we tested the effects of excess Ca2+ on vacuole acidification. Adding micromolar Ca2+ blocked vacuole acidification, whereas chelating Ca2+ accelerated acidification. The effect of adding Ca2+ on acidification was eliminated when the Ca2+/H+ antiporter Vcx1 was absent, indicating that the vacuolar H+ gradient can collapse during Ca2+ stress through Vcx1 activity. This, however, was independent of PI(3,5)P2, suggesting that PI(3,5)P2 plays a role in submicromolar Ca2+ flux but not under Ca2+ shock. To see if the link between Ca2+ and H+ transport was bidirectional, we examined Ca2+ transport when vacuole acidification was inhibited. We found that Ca2+ transport was inhibited by halting V-ATPase activity with Bafilomycin or neutralizing vacuolar pH with chloroquine. Together, these data show that Ca2+ transport and V-ATPase efficacy are connected but not necessarily through PI(3,5)P2.
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Affiliation(s)
- Chi Zhang
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Yilin Feng
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Adam Balutowski
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Gregory E Miner
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - David A Rivera-Kohr
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Michael R Hrabak
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Katherine D Sullivan
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Annie Guo
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Jorge D Calderin
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Rutilio A Fratti
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA; Center for Biophysics & Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA.
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4
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Gokbayrak ZD, Patel D, Brett CL. Acetate and hypertonic stress stimulate vacuole membrane fission using distinct mechanisms. PLoS One 2022; 17:e0271199. [PMID: 35834522 PMCID: PMC9282455 DOI: 10.1371/journal.pone.0271199] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 06/25/2022] [Indexed: 11/19/2022] Open
Abstract
Vacuoles in plants and fungi play critical roles in cell metabolism and osmoregulation. To support these functions, vacuoles change their morphology, e.g. they fragment when these organisms are challenged with draught, high salinity or metabolic stress (e.g. acetate accumulation). In turn, morphology reflects an equilibrium between membrane fusion and fission that determines size, shape and copy number. By studying Saccharomyces cerevisiae and its vacuole as models, conserved molecular mechanisms responsible for fusion have been revealed. However, a detailed understanding of vacuole fission and how these opposing processes respond to metabolism or osmoregulation remain elusive. Herein we describe a new fluorometric assay to measure yeast vacuole fission in vitro. For proof–of–concept, we use this assay to confirm that acetate, a metabolic stressor, triggers vacuole fission and show it blocks homotypic vacuole fusion in vitro. Similarly, hypertonic stress induced by sorbitol or glucose caused robust vacuole fission in vitro whilst inhibiting fusion. Using wortmannin to inhibit phosphatidylinositol (PI) -kinases or rGyp1-46 to inactivate Rab–GTPases, we show that acetate stress likely targets PI signaling, whereas osmotic stress affects Rab signaling on vacuole membranes to stimulate fission. This study sets the stage for further investigation into the mechanisms that change vacuole morphology to support cell metabolism and osmoregulation.
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Affiliation(s)
| | - Dipti Patel
- Department of Biology, Concordia University, Montreal, Quebec, Canada
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5
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Groth A, Ahlmann S, Werner A, Pöggeler S. The vacuolar morphology protein VAC14 plays an important role in sexual development in the filamentous ascomycete Sordaria macrospora. Curr Genet 2022; 68:407-427. [PMID: 35776170 PMCID: PMC9279277 DOI: 10.1007/s00294-022-01244-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 06/01/2022] [Accepted: 06/02/2022] [Indexed: 11/29/2022]
Abstract
The multiprotein Fab1p/PIKfyve-complex regulating the abundance of the phospholipid phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P2) is highly conserved among eukaryotes. In yeast/mammals, it is composed of the phosphatidylinositol 3-phosphate 5-kinase Fab1p/PIKfyve, the PtdIns(3,5)P2 phosphatase Fig4p/Sac3 and the scaffolding subunit Vac14p/ArPIKfyve. The complex is located to vacuolar membranes in yeast and to endosomal membranes in mammals, where it controls the synthesis and turnover of PtdIns(3,5)P2. In this study, we analyzed the role and function of the Fab1p/PIKfyve-complex scaffold protein SmVAC14 in the filamentous ascomycete Sordaria macrospora (Sm). We generated the Smvac14 deletion strain ∆vac14 and performed phenotypic analysis of the mutant. Furthermore, we conducted fluorescence microscopic localization studies of fluorescently labeled SmVAC14 with vacuolar and late endosomal marker proteins. Our results revealed that SmVAC14 is important for maintaining vacuolar size and appearance as well as proper sexual development in S. macrospora. In addition, SmVAC14 plays an important role in starvation stress response. Accordingly, our results propose that the turnover of PtdIns(3,5)P2 is of great significance for developmental processes in filamentous fungi.
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Affiliation(s)
- Anika Groth
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstr. 8, 37077, Göttingen, Germany
| | - Svenja Ahlmann
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstr. 8, 37077, Göttingen, Germany
| | - Antonia Werner
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstr. 8, 37077, Göttingen, Germany
| | - Stefanie Pöggeler
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstr. 8, 37077, Göttingen, Germany.
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6
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Horikiri S, Harada M, Asada R, J Sakamoto J, Furuta M, Tsuchido T. Low Temperature Heating-Induced Death and Vacuole Injury in Cladosporium sphaerospermum Conidia. Biocontrol Sci 2022; 27:107-115. [PMID: 35753793 DOI: 10.4265/bio.27.107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The mechanism of thermal death of mold conidia has not been understood in detail. The purpose of this study is to analyze the death kinetics of heated conidia of Cladosporium sphaerospermum and to ascertain the expectant cell injury responsible for the death. The death of the dormant (resting) conidia of Cladosporium sphaerospermum was examined at temperatures of between 43 and 54℃ with the conventional colony count method. The death reaction apparently followed the first order kinetics, but the Arrhenius plot of the death rate constant demonstrated seemingly a break. The linearity at temperatures higher than that at the break was lost at lower temperatures, suggesting the involvement of an unusual mechanism in the latter temperatures. In the cell morphology, we observed with quinacrine staining the vacuole rupture at a lower temperature but not at a high temperature. Interestingly, the vacuole rupture by low-temperature heating was found to correlate with the viability loss. Furthermore, active protease originally locating in vacuoles was detected in the cytoplasm of the conidia after heated at a low temperature. The results obtained suggest the involvement of potent autophagic cell death induced by low temperature heating of C. sphaerospermum conidia.
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Affiliation(s)
- Shigetoshi Horikiri
- Department of Quantum and Radiation Engineering, Graduate School of Engineering, Osaka Prefecture University.,Panasonic Ecology Systems Co., Ltd
| | - Mami Harada
- Department of Quantum and Radiation Engineering, Graduate School of Engineering, Osaka Prefecture University
| | - Ryoko Asada
- Department of Quantum and Radiation Engineering, Graduate School of Engineering, Osaka Prefecture University.,Research Center of Microorganism Control, Organization for Research Promotion
| | - Jin J Sakamoto
- Research Center of Microorganism Control, Organization for Research Promotion.,Faculty of Chemistry, Materials and Bioengineering, Kansai University
| | - Masakazu Furuta
- Department of Quantum and Radiation Engineering, Graduate School of Engineering, Osaka Prefecture University.,Research Center of Microorganism Control, Organization for Research Promotion
| | - Tetsuaki Tsuchido
- Research Center of Microorganism Control, Organization for Research Promotion
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7
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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: 21] [Impact Index Per Article: 10.5] [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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8
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Nguyen JA, Yates RM. Better Together: Current Insights Into Phagosome-Lysosome Fusion. Front Immunol 2021; 12:636078. [PMID: 33717183 PMCID: PMC7946854 DOI: 10.3389/fimmu.2021.636078] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/18/2021] [Indexed: 12/15/2022] Open
Abstract
Following phagocytosis, the nascent phagosome undergoes maturation to become a phagolysosome with an acidic, hydrolytic, and often oxidative lumen that can efficiently kill and digest engulfed microbes, cells, and debris. The fusion of phagosomes with lysosomes is a principal driver of phagosomal maturation and is targeted by several adapted intracellular pathogens. Impairment of this process has significant consequences for microbial infection, tissue inflammation, the onset of adaptive immunity, and disease. Given the importance of phagosome-lysosome fusion to phagocyte function and the many virulence factors that target it, it is unsurprising that multiple molecular pathways have evolved to mediate this essential process. While the full range of these pathways has yet to be fully characterized, several pathways involving proteins such as members of the Rab GTPases, tethering factors and SNAREs have been identified. Here, we summarize the current state of knowledge to clarify the ambiguities in the field and construct a more comprehensive phagolysosome formation model. Lastly, we discuss how other cellular pathways help support phagolysosome biogenesis and, consequently, phagocyte function.
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Affiliation(s)
- Jenny A Nguyen
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Robin M Yates
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.,Cumming School of Medicine, Snyder Institute of Chronic Disease, University of Calgary, Calgary, AB, Canada
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9
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Peng P, Jia D, Cao L, Lu W, Liu X, Liang C, Pan Z, Fang Z. Akebia saponin E, as a novel PIKfyve inhibitor, induces lysosome-associated cytoplasmic vacuolation to inhibit proliferation of hepatocellular carcinoma cells. JOURNAL OF ETHNOPHARMACOLOGY 2021; 266:113446. [PMID: 33031902 DOI: 10.1016/j.jep.2020.113446] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/30/2020] [Accepted: 09/30/2020] [Indexed: 06/11/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Hepatocellular carcinoma (HCC) is an aggressive malignancy with increasing mortality in China. Screening and identifying effective anticancer compounds from active traditional Chinese herbs for HCC are in demand. Akebia trifoliata (Thunb) Koidz, with pharmacological anti-HCC activities in clinical, has been shown in previous research. In the present research, we elucidated a potential anticancer effect of Akebia saponin E (ASE), which is isolated from the immature seeds of Akebia trifoliata (Thunb.) Koidz, and revealed that ASE could induce severe expanded vacuoles in HCC cells. But the potential mechanism of vacuole-formation and the anti-HCC effects by ASE remain uncover. AIM OF THIS STUDY To elucidate the potential mechanism of vacuole-formation and the proliferation inhibition effects by ASE in HCC cell lines. MATERIALS AND METHODS MTT assay, colony formation assay and flow cytometry were performed to detect cell viability. Immunofluorescence analysis was used to examine the biomarkers of endomembrane. Cells were infected with tandem mRFP-GFP-LC3 lentivirus to assess autophagy flux. RNA-seq was conducted to analyze the genome-wide transcriptional between treatment cell groups. In vitro PIKfyve kinase assay is detected by the ADP-GloTM Kinase Assay Kit. RESULTS ASE could inhibit the proliferation of HCC with severe expanded vacuoles in vitro, and could significantly reduce the size and weight of xenograft tumor in vivo. Further, the vacuoles induced by ASE were aberrant enlarged lysosomes instead of autophagosome or autolysosomes. With cytoplasmic vacuolation, ASE induced a mTOR-independent TFEB activation for lysosomal biogenesis and a decrement of cholesterol levels in HCC cells. Furthermore, ASE could reduce the activity of PIKfyve (phosphoinositide kinase containing a FYVE-type finger), causing aberrant lysosomal biogenesis and cholesterol dyshomeostasis which triggered the expanded vacuole formation. CONCLUSION ASE can prospectively inhibit the kinase activity of PIKfyve to induce lysosome-associated cytoplasmic vacuolation, and may be utilized as an alternative candidate to treat human HCC.
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Affiliation(s)
- Peike Peng
- School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Dongwei Jia
- School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Linna Cao
- School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Wenli Lu
- School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Xiaomei Liu
- School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Chao Liang
- School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Zhiqiang Pan
- School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Zhaoqin Fang
- School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
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10
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Mohamed M, Gardeitchik T, Balasubramaniam S, Guerrero‐Castillo S, Dalloyaux D, van Kraaij S, Venselaar H, Hoischen A, Urban Z, Brandt U, Al‐Shawi R, Simons JP, Frison M, Ngu L, Callewaert B, Spelbrink H, Kallemeijn WW, Aerts JMFG, Waugh MG, Morava E, Wevers RA. Novel defect in phosphatidylinositol 4-kinase type 2-alpha (PI4K2A) at the membrane-enzyme interface is associated with metabolic cutis laxa. J Inherit Metab Dis 2020; 43:1382-1391. [PMID: 32418222 PMCID: PMC7687218 DOI: 10.1002/jimd.12255] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 05/11/2020] [Accepted: 05/13/2020] [Indexed: 12/16/2022]
Abstract
Inherited cutis laxa, or inelastic, sagging skin is a genetic condition of premature and generalised connective tissue ageing, affecting various elastic components of the extracellular matrix. Several cutis laxa syndromes are inborn errors of metabolism and lead to severe neurological symptoms. In a patient with cutis laxa, a choreoathetoid movement disorder, dysmorphic features and intellectual disability we performed exome sequencing to elucidate the underlying genetic defect. We identified the amino acid substitution R275W in phosphatidylinositol 4-kinase type IIα, caused by a homozygous missense mutation in the PI4K2A gene. We used lipidomics, complexome profiling and functional studies to measure phosphatidylinositol 4-phosphate synthesis in the patient and evaluated PI4K2A deficient mice to define a novel metabolic disorder. The R275W residue, located on the surface of the protein, is involved in forming electrostatic interactions with the membrane. The catalytic activity of PI4K2A in patient fibroblasts was severely reduced and lipid mass spectrometry showed that particular acyl-chain pools of PI4P and PI(4,5)P2 were decreased. Phosphoinositide lipids play a major role in intracellular signalling and trafficking and regulate the balance between proliferation and apoptosis. Phosphatidylinositol 4-kinases such as PI4K2A mediate the first step in the main metabolic pathway that generates PI4P, PI(4,5)P2 and PI(3,4,5)P3 . Although neurologic involvement is common, cutis laxa has not been reported previously in metabolic defects affecting signalling. Here we describe a patient with a complex neurological phenotype, premature ageing and a mutation in PI4K2A, illustrating the importance of this enzyme in the generation of inositol lipids with particular acylation characteristics.
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Affiliation(s)
- Miski Mohamed
- Department of PaediatricsRadboud University Medical CenterNijmegenThe Netherlands
| | - Thatjana Gardeitchik
- Department of PaediatricsRadboud University Medical CenterNijmegenThe Netherlands
- Department of GeneticsRadboud University Medical CenterNijmegenThe Netherlands
| | - Shanti Balasubramaniam
- Clinical Genetic DepartmentHospital Kuala Lumpur, Jalan PahangKuala LumpurMalaysia
- Discipline of Genetic Medicine, Sydney Medical SchoolUniversity of SydneySydneyNew South WalesAustralia
- Western Sydney Genetics ProgramThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
| | - Sergio Guerrero‐Castillo
- Radboud Center for Mitochondrial MedicineRadboud University Medical CenterNijmegenThe Netherlands
- Translational Metabolic Laboratory, Department of Laboratory MedicineRadboud University Medical CenterNijmegenThe Netherlands
| | - Daisy Dalloyaux
- Department of PaediatricsRadboud University Medical CenterNijmegenThe Netherlands
| | - Sanne van Kraaij
- Translational Metabolic Laboratory, Department of Laboratory MedicineRadboud University Medical CenterNijmegenThe Netherlands
| | - Hanka Venselaar
- Center of Molecular and Biomolecular InformaticsRadboud University Medical CenterNijmegenThe Netherlands
| | - Alexander Hoischen
- Department of GeneticsRadboud University Medical CenterNijmegenThe Netherlands
- Department of Internal MedicineRadboud University Medical CenterNijmegenThe Netherlands
- Radboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - Zsolt Urban
- Department of Human Genetics, Graduate School of Public HealthUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Ulrich Brandt
- Radboud Center for Mitochondrial MedicineRadboud University Medical CenterNijmegenThe Netherlands
- Translational Metabolic Laboratory, Department of Laboratory MedicineRadboud University Medical CenterNijmegenThe Netherlands
| | - Raya Al‐Shawi
- Wolfson Drug Discovery Unit, Division of Medicine, Royal Free CampusUniversity College LondonLondonUK
| | - J. Paul Simons
- Wolfson Drug Discovery Unit, Division of Medicine, Royal Free CampusUniversity College LondonLondonUK
| | - Michele Frison
- Wolfson Drug Discovery Unit, Division of Medicine, Royal Free CampusUniversity College LondonLondonUK
| | - Lock‐Hock Ngu
- Clinical Genetic DepartmentHospital Kuala Lumpur, Jalan PahangKuala LumpurMalaysia
| | - Bert Callewaert
- Center for Medical GeneticsGhent University HospitalGhentBelgium
| | - Hans Spelbrink
- Department of PaediatricsRadboud University Medical CenterNijmegenThe Netherlands
| | - Wouter W. Kallemeijn
- Department of Medical Biochemistry, Leiden Institute of ChemistryLeiden UniversityLeidenThe Netherlands
- Department of ChemistryImperial College LondonLondonUK
| | - Johannes M. F. G. Aerts
- Department of Medical Biochemistry, Leiden Institute of ChemistryLeiden UniversityLeidenThe Netherlands
| | - Mark G. Waugh
- Lipid and Membrane Biology Group, Institute for Liver & Digestive HealthUniversity College LondonLondonUK
| | - Eva Morava
- Haywards Genetics CenterTulane UniversityNew OrleansLouisianaUSA
- Department of PediatricsUniversity Medical CentreLeuvenBelgium
| | - Ron A. Wevers
- Translational Metabolic Laboratory, Department of Laboratory MedicineRadboud University Medical CenterNijmegenThe Netherlands
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11
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Banerjee S, Kane PM. Regulation of V-ATPase Activity and Organelle pH by Phosphatidylinositol Phosphate Lipids. Front Cell Dev Biol 2020; 8:510. [PMID: 32656214 PMCID: PMC7324685 DOI: 10.3389/fcell.2020.00510] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 05/28/2020] [Indexed: 12/14/2022] Open
Abstract
Luminal pH and the distinctive distribution of phosphatidylinositol phosphate (PIP) lipids are central identifying features of organelles in all eukaryotic cells that are also critical for organelle function. V-ATPases are conserved proton pumps that populate and acidify multiple organelles of the secretory and the endocytic pathway. Complete loss of V-ATPase activity causes embryonic lethality in higher animals and conditional lethality in yeast, while partial loss of V-ATPase function is associated with multiple disease states. On the other hand, many cancer cells increase their virulence by upregulating V-ATPase expression and activity. The pH of individual organelles is tightly controlled and essential for function, but the mechanisms for compartment-specific pH regulation are not completely understood. There is substantial evidence indicating that the PIP content of membranes influences organelle pH. We present recent evidence that PIPs interact directly with subunit isoforms of the V-ATPase to dictate localization of V-ATPase subpopulations and participate in their regulation. In yeast cells, which have only one set of organelle-specific V-ATPase subunit isoforms, the Golgi-enriched lipid PI(4)P binds to the cytosolic domain of the Golgi-enriched a-subunit isoform Stv1, and loss of PI(4)P binding results in mislocalization of Stv1-containing V-ATPases from the Golgi to the vacuole/lysosome. In contrast, levels of the vacuole/lysosome-enriched signaling lipid PI(3,5)P2 affect assembly and activity of V-ATPases containing the Vph1 a-subunit isoform. Mutations in the Vph1 isoform that disrupt the lipid interaction increase sensitivity to stress. These studies have decoded “zip codes” for PIP lipids in the cytosolic N-terminal domain of the a-subunit isoforms of the yeast V-ATPase, and similar interactions between PIP lipids and the V-ATPase subunit isoforms are emerging in higher eukaryotes. In addition to direct effects on the V-ATPase, PIP lipids are also likely to affect organelle pH indirectly, through interactions with other membrane transporters. We discuss direct and indirect effects of PIP lipids on organelle pH, and the functional consequences of the interplay between PIP lipid content and organelle pH.
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Affiliation(s)
- Subhrajit Banerjee
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Patricia M Kane
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
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12
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Severe Consequences of SAC3/FIG4 Phosphatase Deficiency to Phosphoinositides in Patients with Charcot-Marie-Tooth Disease Type-4J. Mol Neurobiol 2019; 56:8656-8667. [PMID: 31313076 DOI: 10.1007/s12035-019-01693-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 07/01/2019] [Indexed: 01/26/2023]
Abstract
Charcot-Marie-Tooth disease type-4J (CMT4J), an autosomal recessively inherited peripheral neuropathy characterized by neuronal degeneration, segmental demyelination, and limb muscle weakness, is caused by compound heterozygous mutations in the SAC3/FIG4 gene, resulting in SAC3/FIG4 protein deficiency. SAC3/FIG4 is a phosphatase that not only turns over PtdIns(3,5)P2 to PtdIns3P but also promotes PtdIns(3,5)P2 synthesis by activating the PIKFYVE kinase that also makes PtdIns5P. Whether CMT4J patients have alterations in PtdIns(3,5)P2, PtdIns5P or in other phosphoinositides (PIs), and if yes, in what direction these changes might be, has never been examined. We performed PI profiling in primary fibroblasts from a cohort of CMT4J patients. Subsequent to myo-[2-3H]inositol cell labeling to equilibrium, steady-state levels of PIs were quantified by HPLC under conditions concurrently detecting PtdIns5P, PtdIns(3,5)P2, and the other PIs. Immunoblotting verified SAC3/FIG4 depletion in CMT4J fibroblasts. Compared to normal human controls (n = 9), both PtdIns(3,5)P2 and PtdIns5P levels were significantly decreased in CMT4J fibroblasts (n = 13) by 36.4 ± 3.6% and 43.1 ± 4.4%, respectively (p < 0.0001). These reductions were independent of patients' gender or disease onset. Although mean values for PtdIns3P in the CMT4J cohort remained unchanged, there were high variations in PtdIns3P among individual patients. Aberrant endolysosomal vacuoles, typically seen under PtdIns(3,5)P2 reduction, were apparent but not in fibroblasts from all patients. The subset of patients without aberrant vacuoles exhibited especially low PtdIns3P levels. Concomitant decreases in PtdIns5P and PtdIns(3,5)P2 and the link between PtdIns3P levels and cellular vacuolization are novel insights shedding further light into the molecular determinants in CMT4J polyneuropathy.
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13
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Min SH, Suzuki A, Weaver L, Guzman J, Chung Y, Jin H, Gonzalez F, Trasorras C, Zhao L, Spruce LA, Seeholzer SH, Behrens EM, Abrams CS. PIKfyve Deficiency in Myeloid Cells Impairs Lysosomal Homeostasis in Macrophages and Promotes Systemic Inflammation in Mice. Mol Cell Biol 2019; 39:e00158-19. [PMID: 31427458 PMCID: PMC6791654 DOI: 10.1128/mcb.00158-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 04/29/2019] [Accepted: 08/12/2019] [Indexed: 01/15/2023] Open
Abstract
Macrophages are professional phagocytes that are essential for host defense and tissue homeostasis. Proper membrane trafficking and degradative functions of the endolysosomal system are known to be critical for the function of these cells. We have found that PIKfyve, the kinase that synthesizes the endosomal phosphoinositide phosphatidylinositol-3,5-bisphosphate, is an essential regulator of lysosomal biogenesis and degradative functions in macrophages. Genetically engineered mice lacking PIKfyve in their myeloid cells (PIKfyvefl/fl LysM-Cre) develop diffuse tissue infiltration of foamy macrophages, hepatosplenomegaly, and systemic inflammation. PIKfyve loss in macrophages causes enlarged endolysosomal compartments and impairs the lysosomal degradative function. Moreover, PIKfyve deficiency increases the cellular levels of lysosomal proteins. Although PIKfyve deficiency reduced the activation of mTORC1 pathway and was associated with increased cleavage of TFEB proteins, this does not translate into transcriptional activation of lysosomal genes, suggesting that PIKfyve modulates the abundance of lysosomal proteins by affecting the degradation of these proteins. Our study shows that PIKfyve modulation of lysosomal degradative activity and protein expression is essential to maintain lysosomal homeostasis in macrophages.
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Affiliation(s)
- Sang Hee Min
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
- Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Aae Suzuki
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Lehn Weaver
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Jessica Guzman
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Yutein Chung
- Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Huiyan Jin
- Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Francina Gonzalez
- Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Claire Trasorras
- Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Liang Zhao
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Lynn A Spruce
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | | | - Edward M Behrens
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Charles S Abrams
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
- Department of Pathology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
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14
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Bellio M, Caux M, Vauclard A, Chicanne G, Gratacap MP, Terrisse AD, Severin S, Payrastre B. Phosphatidylinositol 3 monophosphate metabolizing enzymes in blood platelet production and in thrombosis. Adv Biol Regul 2019; 75:100664. [PMID: 31604685 DOI: 10.1016/j.jbior.2019.100664] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 09/19/2019] [Accepted: 09/30/2019] [Indexed: 02/09/2023]
Abstract
Blood platelets, produced by the fragmentation of megakaryocytes, play a key role in hemostasis and thrombosis. Being implicated in atherothrombosis and other thromboembolic disorders, they represent a major therapeutic target for antithrombotic drug development. Several recent studies have highlighted an important role for the lipid phosphatidylinositol 3 monophosphate (PtdIns3P) in megakaryocytes and platelets. PtdIns3P, present in small amounts in mammalian cells, is involved in the control of endocytic trafficking and autophagy. Its metabolism is finely regulated by specific kinases and phosphatases. Class II (α, β and γ) and III (Vps34) phosphoinositide-3-kinases (PI3Ks), INPP4 and Fig4 are involved in the production of PtdIns3P whereas PIKFyve, myotubularins (MTMs) and type II PIPK metabolize PtdIns3P. By regulating the turnover of different pools of PtdIns3P, class II (PI3KC2α) and class III (Vps34) PI3Ks have been recently involved in the regulation of platelet production and functions. These pools of PtdIns3P appear to modulate membrane organization and intracellular trafficking. Moreover, PIKFyve and INPP4 have been recently implicated in arterial thrombosis. In this review, we will discuss the role of PtdIns3P metabolizing enzymes in platelet production and function. Potential new anti-thrombotic therapeutic perspectives based on inhibitors targeting specifically PtdIns3P metabolizing enzymes will also be commented.
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Affiliation(s)
- Marie Bellio
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Manuella Caux
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Alicia Vauclard
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Gaëtan Chicanne
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Marie-Pierre Gratacap
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Anne-Dominique Terrisse
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Sonia Severin
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - Bernard Payrastre
- Inserm U1048 and Université Paul Sabatier, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France; Laboratoire d'Hématologie, Hopital Universitaire de Toulouse, Toulouse, France.
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15
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Bouhamdani N, Comeau D, Cormier K, Turcotte S. STF-62247 accumulates in lysosomes and blocks late stages of autophagy to selectively target von Hippel-Lindau-inactivated cells. Am J Physiol Cell Physiol 2019; 316:C605-C620. [DOI: 10.1152/ajpcell.00483.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Autophagy is a highly conserved, homeostatic process by which cytosolic components reach lysosomes for degradation. The roles played by different autophagic processes in cancer are complex and remain cancer type and stage dependent. Renal cell carcinoma (RCC) is the most common subtype of kidney cancer and is characterized by the inactivation of the von Hippel-Lindau (VHL) tumor suppressor. Our previous study identified a small compound, STF-62247, as an autophagy-modulating molecule causing selective cytotoxicity for VHL-inactivated cells. This present study investigates the effects of STF-62247 specifically on the macroautophagic flux to better characterize its mechanism of action in RCC. Our results clearly demonstrate that this compound is a potent blocker of late stages of autophagy. We show that inhibiting autophagy by CRISPR knockouts of autophagy-related genes rendered VHL-deficient cells insensitive to STF-62247, uncovering the importance of the autophagic pathway in STF-selective cell death. By exploiting the autofluorescence of STF-62247, we pinpointed its cellular localization to lysosomes. Finally, in response to prolonged STF treatments, we show that VHL-proficient cells are able to surmount the block in late stages of autophagy by restoring their lysosome numbers. Conversely, an increase in autophagic vesicles accompanied by a time-dependent decrease in lysosomes was observed in VHL-deficient cells. This is the first mechanistic study investigating STF-62447’s effects on the autophagic flux in RCC. Importantly, our study reclassifies STF-62247 as a blocker of later stages of autophagy and highlights the possibility of blocking this process through lysosome disruption in VHL-mutated RCCs.
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Affiliation(s)
- Nadia Bouhamdani
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, New Brunswick, Canada
- Atlantic Cancer Research Institute, Moncton, New Brunswick, Canada
| | - Dominique Comeau
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, New Brunswick, Canada
- Atlantic Cancer Research Institute, Moncton, New Brunswick, Canada
| | - Kevin Cormier
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, New Brunswick, Canada
- Atlantic Cancer Research Institute, Moncton, New Brunswick, Canada
| | - Sandra Turcotte
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, New Brunswick, Canada
- Atlantic Cancer Research Institute, Moncton, New Brunswick, Canada
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16
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Banerjee S, Clapp K, Tarsio M, Kane PM. Interaction of the late endo-lysosomal lipid PI(3,5)P2 with the Vph1 isoform of yeast V-ATPase increases its activity and cellular stress tolerance. J Biol Chem 2019; 294:9161-9171. [PMID: 31023825 DOI: 10.1074/jbc.ra119.008552] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/22/2019] [Indexed: 12/30/2022] Open
Abstract
The low-level endo-lysosomal signaling lipid, phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2), is required for full assembly and activity of vacuolar H+-ATPases (V-ATPases) containing the vacuolar a-subunit isoform Vph1 in yeast. The cytosolic N-terminal domain of Vph1 is also recruited to membranes in vivo in a PI(3,5)P2-dependent manner, but it is not known if its interaction with PI(3,5)P2 is direct. Here, using biochemical characterization of isolated yeast vacuolar vesicles, we demonstrate that addition of exogenous short-chain PI(3,5)P2 to Vph1-containing vacuolar vesicles activates V-ATPase activity and proton pumping. Modeling of the cytosolic N-terminal domain of Vph1 identified two membrane-oriented sequences that contain clustered basic amino acids. Substitutions in one of these sequences (231KTREYKHK) abolished the PI(3,5)P2-dependent activation of V-ATPase without affecting basal V-ATPase activity. We also observed that vph1 mutants lacking PI(3,5)P2 activation have enlarged vacuoles relative to those in WT cells. These mutants exhibit a significant synthetic growth defect when combined with deletion of Hog1, a kinase important for signaling the transcriptional response to osmotic stress. The results suggest that PI(3,5)P2 interacts directly with Vph1, and that this interaction both activates V-ATPase activity and protects cells from stress.
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Affiliation(s)
- Subhrajit Banerjee
- From the Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York 13210
| | - Kaitlyn Clapp
- From the Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York 13210
| | - Maureen Tarsio
- From the Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York 13210
| | - Patricia M Kane
- From the Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York 13210
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17
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Sharma G, Guardia CM, Roy A, Vassilev A, Saric A, Griner LN, Marugan J, Ferrer M, Bonifacino JS, DePamphilis ML. A family of PIKFYVE inhibitors with therapeutic potential against autophagy-dependent cancer cells disrupt multiple events in lysosome homeostasis. Autophagy 2019; 15:1694-1718. [PMID: 30806145 DOI: 10.1080/15548627.2019.1586257] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
High-throughput screening identified 5 chemical analogs (termed the WX8-family) that disrupted 3 events in lysosome homeostasis: (1) lysosome fission via tubulation without preventing homotypic lysosome fusion; (2) trafficking of molecules into lysosomes without altering lysosomal acidity, and (3) heterotypic fusion between lysosomes and autophagosomes. Remarkably, these compounds did not prevent homotypic fusion between lysosomes, despite the fact that homotypic fusion required some of the same machinery essential for heterotypic fusion. These effects varied 400-fold among WX8-family members, were time and concentration dependent, reversible, and resulted primarily from their ability to bind specifically to the PIKFYVE phosphoinositide kinase. The ability of the WX8-family to prevent lysosomes from participating in macroautophagy/autophagy suggested they have therapeutic potential in treating autophagy-dependent diseases. In fact, the most potent family member (WX8) was 100-times more lethal to 'autophagy-addicted' melanoma A375 cells than the lysosomal inhibitors hydroxychloroquine and chloroquine. In contrast, cells that were insensitive to hydroxychloroquine and chloroquine were also insensitive to WX8. Therefore, the WX8-family of PIKFYVE inhibitors provides a basis for developing drugs that could selectively kill autophagy-dependent cancer cells, as well as increasing the effectiveness of established anti-cancer therapies through combinatorial treatments. Abbreviations: ACTB: actin beta; Baf: bafilomycin A1; BECN1: beclin 1; BODIPY: boron-dipyrromethene; BORC: BLOC-1 related complex; BRAF: B-Raf proto-oncogene, serine/threonine kinase; BSA: bovine serum albumin; CTSD: cathepsin D; CQ: chloroquine; DNA: deoxyribonucleic acid; EC50: half maximal effective concentration; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFP: green fluorescent protein; HCQ: hydroxychloroquine; HOPS complex: homotypic fusion and protein sorting complex; Kd: equilibrium binding constant; IC50: half maximal inhibitory concentration; KO: knockout; LAMP1: lysosomal associated membrane protein 1; MAP1LC3A: microtubule associated protein 1 light chain 3 alpha; MES: 2-(N-morpholino)ethanesulphonic acid; MTOR: mechanistic target of rapamycin kinase; μM: micromolar; NDF: 3-methylbenzaldehyde (2,6-dimorpholin-4-ylpyrimidin-4-yl)hydrazine;NEM: N-ethylmaleimide; NSF: N-ethylmaleimide sensitive factor; PBS: phosphate-buffered saline; PIKFYVE: phosphoinositide kinase, FYVE-type zinc finger containing; PIP4K2C: phosphatidylinositol-5-phosphate 4-kinase type 2 gamma; PtdIns3P: phosphatidylinositol 3-phosphate; PtdIns(3,5)P2: phosphatidylinositol 3,5-biphosphate; RFP: red fluorescent protein; RPS6: ribosomal protein S6; RPS6KB1: ribosomal protein S6 kinase B1; SQSTM1: sequestosome 1; TWEEN 20: polysorbate 20; V-ATPase: vacuolar-type H+-translocating ATPase; VPS39: VPS39 subunit of HOPS complex; VPS41: VPS41 subunit of HOPS complex; WWL: benzaldehyde [2,6-di(4-morpholinyl)-4-pyrimidinyl]hydrazone; WX8: 1H-indole-3-carbaldehyde [4-anilino-6-(4-morpholinyl)-1,3,5-triazin-2-yl]hydrazine; XBA: N-(3-chloro-4-fluorophenyl)-4,6-dimorpholino-1,3,5-triazin-2-amine hydrochloride; XB6: N-(4-ethylphenyl)-4,6-dimorpholino-1,3,5-triazin-2-amine hydrochloride.
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Affiliation(s)
- Gaurav Sharma
- Division of Developmental Biology, National Institute of Child Health & Human Development, National Institutes of Health , Bethesda , MD , USA
| | - Carlos M Guardia
- Cell Biology and Neurobiology Branch, National Institute of Child Health & Human Development, National Institutes of Health , Bethesda , MD , USA
| | - Ajit Roy
- Division of Developmental Biology, National Institute of Child Health & Human Development, National Institutes of Health , Bethesda , MD , USA
| | - Alex Vassilev
- Division of Developmental Biology, National Institute of Child Health & Human Development, National Institutes of Health , Bethesda , MD , USA
| | - Amra Saric
- Cell Biology and Neurobiology Branch, National Institute of Child Health & Human Development, National Institutes of Health , Bethesda , MD , USA
| | - Lori N Griner
- Division of Developmental Biology, National Institute of Child Health & Human Development, National Institutes of Health , Bethesda , MD , USA
| | - Juan Marugan
- Division of Pre-Clinical Innovation, NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health , Rockville , MD , USA
| | - Marc Ferrer
- Division of Pre-Clinical Innovation, NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health , Rockville , MD , USA
| | - Juan S Bonifacino
- Cell Biology and Neurobiology Branch, National Institute of Child Health & Human Development, National Institutes of Health , Bethesda , MD , USA
| | - Melvin L DePamphilis
- Division of Developmental Biology, National Institute of Child Health & Human Development, National Institutes of Health , Bethesda , MD , USA
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18
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Bissig C, Croisé P, Heiligenstein X, Hurbain I, Lenk GM, Kaufman E, Sannerud R, Annaert W, Meisler MH, Weisman LS, Raposo G, van Niel G. The PIKfyve complex regulates the early melanosome homeostasis required for physiological amyloid formation. J Cell Sci 2019; 132:jcs.229500. [PMID: 30709920 DOI: 10.1242/jcs.229500] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 01/14/2019] [Indexed: 12/23/2022] Open
Abstract
The metabolism of PI(3,5)P2 is regulated by the PIKfyve, VAC14 and FIG4 complex, mutations in which are associated with hypopigmentation in mice. These pigmentation defects indicate a key, but as yet unexplored, physiological relevance of this complex in the biogenesis of melanosomes. Here, we show that PIKfyve activity regulates formation of amyloid matrix composed of PMEL protein within the early endosomes in melanocytes, called stage I melanosomes. PIKfyve activity controls the membrane remodeling of stage I melanosomes, which regulates PMEL abundance, sorting and processing. PIKfyve activity also affects stage I melanosome kiss-and-run interactions with lysosomes, which are required for PMEL amyloidogenesis and the establishment of melanosome identity. Mechanistically, PIKfyve activity promotes both the formation of membrane tubules from stage I melanosomes and their release by modulating endosomal actin branching. Taken together, our data indicate that PIKfyve activity is a key regulator of the melanosomal import-export machinery that fine tunes the formation of functional amyloid fibrils in melanosomes and the maintenance of melanosome identity.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Christin Bissig
- Structure and Membrane Compartments, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France
| | - Pauline Croisé
- IPNP, Institute of Psychiatry and Neuroscience of Paris, Hopital Saint-Anne, Université Paris Descartes, INSERM U894, 75014 Paris, France
| | - Xavier Heiligenstein
- Structure and Membrane Compartments, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France.,Cell and Tissue Imaging Facility, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France
| | - Ilse Hurbain
- Structure and Membrane Compartments, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France.,Cell and Tissue Imaging Facility, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France
| | - Guy M Lenk
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109-5618, USA
| | - Emily Kaufman
- Life Science Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - Ragna Sannerud
- VIB Center for Brain & Disease Research, 3000 Leuven, Belgium.,KU Leuven, Department of Neurosciences, 3000 Leuven, Belgium
| | - Wim Annaert
- VIB Center for Brain & Disease Research, 3000 Leuven, Belgium.,KU Leuven, Department of Neurosciences, 3000 Leuven, Belgium
| | - Miriam H Meisler
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109-5618, USA
| | - Lois S Weisman
- Life Science Institute, University of Michigan, Ann Arbor, MI 48109-2216, USA
| | - Graça Raposo
- Structure and Membrane Compartments, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France.,Cell and Tissue Imaging Facility, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France
| | - Guillaume van Niel
- Structure and Membrane Compartments, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France .,IPNP, Institute of Psychiatry and Neuroscience of Paris, Hopital Saint-Anne, Université Paris Descartes, INSERM U894, 75014 Paris, France.,Cell and Tissue Imaging Facility, Institut Curie, Paris Sciences & Lettres Research University, Centre National de la Recherche Scientifique, UMR144, 75005 Paris, France
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19
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Buckley CM, Heath VL, Guého A, Bosmani C, Knobloch P, Sikakana P, Personnic N, Dove SK, Michell RH, Meier R, Hilbi H, Soldati T, Insall RH, King JS. PIKfyve/Fab1 is required for efficient V-ATPase and hydrolase delivery to phagosomes, phagosomal killing, and restriction of Legionella infection. PLoS Pathog 2019; 15:e1007551. [PMID: 30730983 PMCID: PMC6382210 DOI: 10.1371/journal.ppat.1007551] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 02/20/2019] [Accepted: 01/03/2019] [Indexed: 12/11/2022] Open
Abstract
By engulfing potentially harmful microbes, professional phagocytes are continually at risk from intracellular pathogens. To avoid becoming infected, the host must kill pathogens in the phagosome before they can escape or establish a survival niche. Here, we analyse the role of the phosphoinositide (PI) 5-kinase PIKfyve in phagosome maturation and killing, using the amoeba and model phagocyte Dictyostelium discoideum. PIKfyve plays important but poorly understood roles in vesicular trafficking by catalysing formation of the lipids phosphatidylinositol (3,5)-bisphosphate (PI(3,5)2) and phosphatidylinositol-5-phosphate (PI(5)P). Here we show that its activity is essential during early phagosome maturation in Dictyostelium. Disruption of PIKfyve inhibited delivery of both the vacuolar V-ATPase and proteases, dramatically reducing the ability of cells to acidify newly formed phagosomes and digest their contents. Consequently, PIKfyve- cells were unable to generate an effective antimicrobial environment and efficiently kill captured bacteria. Moreover, we demonstrate that cells lacking PIKfyve are more susceptible to infection by the intracellular pathogen Legionella pneumophila. We conclude that PIKfyve-catalysed phosphoinositide production plays a crucial and general role in ensuring early phagosomal maturation, protecting host cells from diverse pathogenic microbes.
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Affiliation(s)
- Catherine M. Buckley
- Centre for Membrane Interactions and Dynamics, Department of Biomedical Sciences, University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom
- Bateson Centre, University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom
| | - Victoria L. Heath
- Institute of Cardiovascular Sciences, Institute for Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Aurélie Guého
- Department of Biochemistry, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Cristina Bosmani
- Department of Biochemistry, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Paulina Knobloch
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Phumzile Sikakana
- Centre for Membrane Interactions and Dynamics, Department of Biomedical Sciences, University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom
| | - Nicolas Personnic
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Stephen K. Dove
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Robert H. Michell
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Roger Meier
- Institute of Molecular Life Sciences, University of Zürich, Zürich, Switzerland
| | - Hubert Hilbi
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Thierry Soldati
- Department of Biochemistry, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Robert H. Insall
- CRUK Beatson Institute, Switchback Road, Bearsden, Glasgow, United Kingdom
| | - Jason S. King
- Centre for Membrane Interactions and Dynamics, Department of Biomedical Sciences, University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom
- Bateson Centre, University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom
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20
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Sbrissa D, Naisan G, Ikonomov OC, Shisheva A. Apilimod, a candidate anticancer therapeutic, arrests not only PtdIns(3,5)P2 but also PtdIns5P synthesis by PIKfyve and induces bafilomycin A1-reversible aberrant endomembrane dilation. PLoS One 2018; 13:e0204532. [PMID: 30240452 PMCID: PMC6150535 DOI: 10.1371/journal.pone.0204532] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Accepted: 09/10/2018] [Indexed: 01/02/2023] Open
Abstract
PIKfyve, an evolutionarily conserved kinase synthesizing PtdIns5P and PtdIns(3,5)P2, is crucial for mammalian cell proliferation and viability. Accordingly, PIKfyve inhibitors are now in clinical trials as anti-cancer drugs. Among those, apilimod is the most promising, yet its potency to inhibit PIKfyve and affect endomembrane homeostasis is only partially characterized. We demonstrate here for the first time that apilimod powerfully inhibited in vitro synthesis of PtdIns5P along with that of PtdIns(3,5)P2. HPLC-based resolution of intracellular phosphoinositides (PIs) revealed that apilimod triggered a marked reduction of both lipids in the context of intact cells. Notably, there was also a profound rise in PtdIns3P resulting from arrested PtdIns3P consumption for PtdIns(3,5)P2 synthesis. As typical for PIKfyve inhibition and the concomitant PtdIns(3,5)P2 reduction, apilimod induced the appearance of dilated endomembrane structures in the form of large translucent cytoplasmic vacuoles. Remarkably, bafilomycin A1 (BafA1) fully reversed the aberrant cell phenotype back to normal and completely precluded the appearance of cytoplasmic vacuoles when added prior to apilimod. Inspection of the PI profiles ruled out restoration of the reduced PtdIns(3,5)P2 pool as a molecular mechanism underlying BafA1 rescue. Rather, we found that BafA1 markedly attenuated the PtdIns3P elevation under PIKfyve inhibition. This was accompanied by profoundly decreased endosomal recruitment of fusogenic EEA1. Together, our data demonstrate that apilimod inhibits not only PtdIns(3,5)P2 but also PtdIns5P synthesis and that the cytoplasmic vacuolization triggered by the inhibitor is precluded or reversed by BafA1 through a mechanism associated, in part, with reduction in both PtdIns3P levels and EEA1 membrane recruitment.
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Affiliation(s)
- Diego Sbrissa
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Ghassan Naisan
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Ognian C. Ikonomov
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Assia Shisheva
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
- * E-mail:
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21
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Chintaluri K, Goulden BD, Celmenza C, Saffi G, Miraglia E, Hammond GRV, Botelho RJ. The PH domain from the Toxoplasma gondii PH-containing protein-1 (TgPH1) serves as an ectopic reporter of phosphatidylinositol 3-phosphate in mammalian cells. PLoS One 2018; 13:e0198454. [PMID: 29870544 PMCID: PMC5988325 DOI: 10.1371/journal.pone.0198454] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 05/18/2018] [Indexed: 12/29/2022] Open
Abstract
Phosphoinositide (PtdInsP) lipids recruit effector proteins to membranes to mediate a variety of functions including signal transduction and membrane trafficking. Each PtdInsP binds to a specific set of effectors through characteristic protein domains such as the PH, FYVE and PX domains. Domains with high affinity for a single PtdInsP species are useful as probes to visualize the distribution and dynamics of that PtdInsP. The endolysosomal system is governed by two primary PtdInsPs: phosphatidylinositol 3-phosphate [PtdIns(3)P] and phosphatidylinositol 3,5-bisphosphate [PtdIns(3,5)P2], which are thought to localize and control early endosomes and lysosomes/late endosomes, respectively. While PtdIns(3)P has been analysed with mammalian-derived PX and FYVE domains, PtdIns(3,5)P2 indicators remain controversial. Thus, complementary probes against these PtdInsPs are needed, including those originating from non-mammalian proteins. Here, we characterized in mammalian cells the dynamics of the PH domain from PH-containing protein-1 from the parasite Toxoplasma gondii (TgPH1), which was previously shown to bind PtdIns(3,5)P2 in vitro. However, we show that TgPH1 retains membrane-binding in PIKfyve-inhibited cells, suggesting that TgPH1 is not a viable PtdIns(3,5)P2 marker in mammalian cells. Instead, PtdIns(3)P depletion using pharmacological and enzyme-based assays dissociated TgPH1 from membranes. Indeed, TgPH1 co-localized with Rab5-positive early endosomes. In addition, TgPH1 co-localized and behaved similarly to the PX domain of p40phox and FYVE domain of EEA1, which are commonly used as PtdIns(3)P indicators. Collectively, TgPH1 offers a complementary reporter for PtdIns(3)P derived from a non-mammalian protein and that is distinct from commonly employed PX and FYVE domain-based probes.
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Affiliation(s)
- Krishna Chintaluri
- Department of Chemistry, Ryerson University, Toronto, Ontario, Canada
- The Molecular Science Graduate Program, Ryerson University, Toronto, Ontario, Canada
| | - Brady D. Goulden
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Camilyn Celmenza
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Golam Saffi
- Department of Chemistry, Ryerson University, Toronto, Ontario, Canada
- The Molecular Science Graduate Program, Ryerson University, Toronto, Ontario, Canada
| | - Emily Miraglia
- Department of Chemistry, Ryerson University, Toronto, Ontario, Canada
| | - Gerald R. V. Hammond
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
| | - Roberto J. Botelho
- Department of Chemistry, Ryerson University, Toronto, Ontario, Canada
- The Molecular Science Graduate Program, Ryerson University, Toronto, Ontario, Canada
- * E-mail:
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22
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Wilson ZN, Scott AL, Dowell RD, Odorizzi G. PI(3,5)P 2 controls vacuole potassium transport to support cellular osmoregulation. Mol Biol Cell 2018; 29:1718-1731. [PMID: 29791245 PMCID: PMC6080712 DOI: 10.1091/mbc.e18-01-0015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Lysosomes are dynamic organelles with critical roles in cellular physiology. The lysosomal signaling lipid phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2) is a key regulator that has been implicated to control lysosome ion homeostasis, but the scope of ion transporters targeted by PI(3,5)P2 and the purpose of this regulation is not well understood. Through an unbiased screen in Saccharomyces cerevisiae, we identified loss-of-function mutations in the vacuolar H+-ATPase (V-ATPase) and in Vnx1, a vacuolar monovalent cation/proton antiporter, as suppressor mutations that relieve the growth defects and osmotic swelling of vacuoles (lysosomes) in yeast lacking PI(3,5)P2. We observed that depletion of PI(3,5)P2 synthesis in yeast causes a robust accumulation of multiple cations, most notably an ∼85 mM increase in the cellular concentration of potassium, a critical ion used by cells to regulate osmolarity. The accumulation of potassium and other cations in PI(3,5)P2-deficient yeast is relieved by mutations that inactivate Vnx1 or inactivate the V-ATPase and by mutations that increase the activity of a vacuolar cation export channel, Yvc1. Collectively, our data demonstrate that PI(3,5)P2 signaling orchestrates vacuole/lysosome cation transport to aid cellular osmoregulation.
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Affiliation(s)
- Zachary N Wilson
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347
| | - Amber L Scott
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347
| | - Robin D Dowell
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347
| | - Greg Odorizzi
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347
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23
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Bissig C, Hurbain I, Raposo G, van Niel G. PIKfyve activity regulates reformation of terminal storage lysosomes from endolysosomes. Traffic 2017; 18:747-757. [DOI: 10.1111/tra.12525] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 08/25/2017] [Accepted: 08/25/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Christin Bissig
- Institut Curie; PSL Research University, CNRS, UMR144; Paris France
- Sorbonne Universités; UPMC Univ Paris 06, CNRS, UMR 144; Paris France
| | - Ilse Hurbain
- Institut Curie; PSL Research University, CNRS, UMR144; Paris France
- Sorbonne Universités; UPMC Univ Paris 06, CNRS, UMR 144; Paris France
- Cell and Tissue Imaging Core Facility PICT-IBiSA; Institut Curie; Paris France
| | - Graça Raposo
- Institut Curie; PSL Research University, CNRS, UMR144; Paris France
- Sorbonne Universités; UPMC Univ Paris 06, CNRS, UMR 144; Paris France
- Cell and Tissue Imaging Core Facility PICT-IBiSA; Institut Curie; Paris France
| | - Guillaume van Niel
- Institut Curie; PSL Research University, CNRS, UMR144; Paris France
- Sorbonne Universités; UPMC Univ Paris 06, CNRS, UMR 144; Paris France
- Cell and Tissue Imaging Core Facility PICT-IBiSA; Institut Curie; Paris France
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24
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A novel fluorescent probe reveals starvation controls the commitment of amyloid precursor protein to the lysosome. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017. [DOI: 10.1016/j.bbamcr.2017.06.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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25
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Baxi K, Ghavidel A, Waddell B, Harkness TA, de Carvalho CE. Regulation of Lysosomal Function by the DAF-16 Forkhead Transcription Factor Couples Reproduction to Aging in Caenorhabditis elegans. Genetics 2017; 207:83-101. [PMID: 28696216 PMCID: PMC5586388 DOI: 10.1534/genetics.117.204222] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 07/03/2017] [Indexed: 02/06/2023] Open
Abstract
Aging in eukaryotes is accompanied by widespread deterioration of the somatic tissue. Yet, abolishing germ cells delays the age-dependent somatic decline in Caenorhabditis elegans In adult worms lacking germ cells, the activation of the DAF-9/DAF-12 steroid signaling pathway in the gonad recruits DAF-16 activity in the intestine to promote longevity-associated phenotypes. However, the impact of this pathway on the fitness of normally reproducing animals is less clear. Here, we explore the link between progeny production and somatic aging and identify the loss of lysosomal acidity-a critical regulator of the proteolytic output of these organelles-as a novel biomarker of aging in C. elegans The increase in lysosomal pH in older worms is not a passive consequence of aging, but instead is timed with the cessation of reproduction, and correlates with the reduction in proteostasis in early adult life. Our results further implicate the steroid signaling pathway and DAF-16 in dynamically regulating lysosomal pH in the intestine of wild-type worms in response to the reproductive cycle. In the intestine of reproducing worms, DAF-16 promotes acidic lysosomes by upregulating the expression of v-ATPase genes. These findings support a model in which protein clearance in the soma is linked to reproduction in the gonad via the active regulation of lysosomal acidification.
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Affiliation(s)
- Kunal Baxi
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N5E2, Canada
| | - Ata Ghavidel
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N5E2, Canada
| | - Brandon Waddell
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N5E2, Canada
| | - Troy A Harkness
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N5E2, Canada
| | - Carlos E de Carvalho
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N5E2, Canada
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26
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In Vivo Indicators of Cytoplasmic, Vacuolar, and Extracellular pH Using pHluorin2 in Candida albicans. mSphere 2017; 2:mSphere00276-17. [PMID: 28685162 PMCID: PMC5497024 DOI: 10.1128/msphere.00276-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 06/20/2017] [Indexed: 11/20/2022] Open
Abstract
Candida albicans is an opportunistic fungal pathogen that colonizes the reproductive and gastrointestinal tracts of its human host. It can also invade the bloodstream and deeper organs of immunosuppressed individuals, and thus it encounters enormous variations in external pH in vivo. Accordingly, survival within such diverse niches necessitates robust adaptive responses to regulate intracellular pH. However, the impact of antifungal drugs upon these adaptive responses, and on intracellular pH in general, is not well characterized. Furthermore, the tools and methods currently available to directly monitor intracellular pH in C. albicans, as well as other fungal pathogens, have significant limitations. To address these issues, we developed a new and improved set of pH sensors based on the pH-responsive fluorescent protein pHluorin. This includes a cytoplasmic sensor, a probe that localizes inside the fungal vacuole (an acidified compartment that plays a central role in intracellular pH homeostasis), and a cell surface probe that can detect changes in extracellular pH. These tools can be used to monitor pH within single C. albicans cells or in cell populations in real time through convenient and high-throughput assays. Environmental or chemically induced stresses often trigger physiological responses that regulate intracellular pH. As such, the capacity to detect pH changes in real time and within live cells is of fundamental importance to essentially all aspects of biology. In this respect, pHluorin, a pH-sensitive variant of green fluorescent protein, has provided an invaluable tool to detect such responses. Here, we report the adaptation of pHluorin2 (PHL2), a substantially brighter variant of pHluorin, for use with the human fungal pathogen Candida albicans. As well as a cytoplasmic PHL2 indicator, we describe a version that specifically localizes within the fungal vacuole, an acidified subcellular compartment with important functions in nutrient storage and pH homeostasis. In addition, by means of a glycophosphatidylinositol-anchored PHL2-fusion protein, we generated a cell surface pH sensor. We demonstrated the utility of these tools in several applications, including accurate intracellular and extracellular pH measurements in individual cells via flow cytometry and in cell populations via a convenient plate reader-based protocol. The PHL2 tools can also be used for endpoint as well as time course experiments and to conduct chemical screens to identify drugs that alter normal pH homeostasis. These tools enable observation of the highly dynamic intracellular pH shifts that occur throughout the fungal growth cycle, as well as in response to various chemical treatments. IMPORTANCECandida albicans is an opportunistic fungal pathogen that colonizes the reproductive and gastrointestinal tracts of its human host. It can also invade the bloodstream and deeper organs of immunosuppressed individuals, and thus it encounters enormous variations in external pH in vivo. Accordingly, survival within such diverse niches necessitates robust adaptive responses to regulate intracellular pH. However, the impact of antifungal drugs upon these adaptive responses, and on intracellular pH in general, is not well characterized. Furthermore, the tools and methods currently available to directly monitor intracellular pH in C. albicans, as well as other fungal pathogens, have significant limitations. To address these issues, we developed a new and improved set of pH sensors based on the pH-responsive fluorescent protein pHluorin. This includes a cytoplasmic sensor, a probe that localizes inside the fungal vacuole (an acidified compartment that plays a central role in intracellular pH homeostasis), and a cell surface probe that can detect changes in extracellular pH. These tools can be used to monitor pH within single C. albicans cells or in cell populations in real time through convenient and high-throughput assays.
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27
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Pérez Koldenkova V, Hatsugai N. Vacuolar convolution: possible mechanisms and role of phosphatidylinositol 3,5-bisphosphate. FUNCTIONAL PLANT BIOLOGY : FPB 2017; 44:751-760. [PMID: 32480604 DOI: 10.1071/fp16443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 05/19/2017] [Indexed: 06/11/2023]
Abstract
The central or lytic vacuole is the largest intracellular organelle in plant cells, but we know unacceptably little about the mechanisms regulating its function in vivo. The underlying reasons are related to difficulties in accessing this organelle without disrupting the cellular integrity and to the dynamic morphology of the vacuole, which lacks a defined structure. Among such morphological changes, vacuolar convolution is probably the most commonly observed event, reflected in the (reversible) transformation of a large central vacuole into a structure consisting of interconnected bubbles of a smaller size. Such behaviour is observed in plant cells subjected to hyperosmotic stress but also takes place in physiological conditions (e.g. during stomatal closure). Although vacuolar convolution is a relatively common phenomenon in plants, studies aimed at elucidating its execution mechanisms are rather scarce. In the present review, we analyse the available evidence on the participation of the cellular cytoskeleton and ion transporters in vacuolar morphology dynamics, putting special emphasis on the available evidence of the role played by phosphatidylinositol 3,5-bisphosphate in this process.
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Affiliation(s)
- Vadim Pérez Koldenkova
- Laboratorio Nacional de Microscopía Avanzada, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Av. Cuauhtémoc, 330, Col. Doctores, Del. Cuauhtémoc. 06720, México D.F., Mexico
| | - Noriyuki Hatsugai
- Department of Plant Biology, Microbial and Plant Genomics Institute, University of Minnesota St Paul, MN 55108, USA
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28
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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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29
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Buckley CM, King JS. Drinking problems: mechanisms of macropinosome formation and maturation. FEBS J 2017; 284:3778-3790. [DOI: 10.1111/febs.14115] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 04/25/2017] [Accepted: 05/17/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Catherine M. Buckley
- Department of Biomedical Sciences Centre for Membrane Interactions and Dynamics University of Sheffield UK
- Bateson Centre University of Sheffield UK
| | - Jason S. King
- Department of Biomedical Sciences Centre for Membrane Interactions and Dynamics University of Sheffield UK
- Bateson Centre University of Sheffield UK
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30
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Gilden JK, Umaer K, Kruzel EK, Hecht O, Correa RO, Mansfield JM, Bangs JD. The role of the PI(3,5)P 2 kinase TbFab1 in endo/lysosomal trafficking in Trypanosoma brucei. Mol Biochem Parasitol 2017; 214:52-61. [PMID: 28356223 DOI: 10.1016/j.molbiopara.2017.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 03/22/2017] [Accepted: 03/23/2017] [Indexed: 12/01/2022]
Abstract
Protein trafficking through endo/lysosomal compartments is critically important to the biology of the protozoan parasite Trypanosoma brucei, but the routes material may take to the lysosome, as well as the molecular factors regulating those routes, remain incompletely understood. Phosphoinositides are signaling phospholipids that regulate many trafficking events by recruiting specific effector proteins to discrete membrane subdomains. In this study, we investigate the role of one phosphoinositide, PI(3,5)P2 in T. brucei. We find a low steady state level of PI(3,5)P2 in bloodstream form parasites comparable to that of other organisms. RNAi knockdown of the putative PI(3)P-5 kinase TbFab1 decreases the PI(3,5)P2 pool leading to rapid cell death. TbFab1 and PI(3,5)P2 both localize strongly to late endo/lysosomes. While most trafficking functions were intact in TbFab1 deficient cells, including both endocytic and biosynthetic trafficking to the lysosome, lysosomal turnover of an endogenous ubiquitinylated membrane protein, ISG65, was completely blocked suggesting that TbFab1 plays a role in the ESCRT-mediated late endosomal/multivesicular body degradative pathways. Knockdown of a second component of PI(3,5)P2 metabolism, the PI(3,5)P2 phosphatase TbFig4, also resulted in delayed turnover of ISG65. Together, these results demonstrate an essential role for PI(3,5)P2 in the turnover of ubiquitinylated membrane proteins and in trypanosome endomembrane biology.
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Affiliation(s)
- Julia K Gilden
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA.
| | - Khan Umaer
- Department of Microbiology Immunology, School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, NY, USA.
| | - Emilia K Kruzel
- Department of Microbiology Immunology, School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, NY, USA.
| | - Oliver Hecht
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA.
| | - Renan O Correa
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA.
| | - John M Mansfield
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA.
| | - James D Bangs
- Department of Microbiology Immunology, School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, NY, USA.
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31
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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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32
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The amyloid precursor protein (APP) binds the PIKfyve complex and modulates its function. Biochem Soc Trans 2016; 44:185-90. [PMID: 26862204 DOI: 10.1042/bst20150179] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Phosphoinositides are important components of eukaryotic membranes that are required for multiple forms of membrane dynamics. Phosphoinositides are involved in defining membrane identity, mediate cell signalling and control membrane trafficking events. Due to their pivotal role in membrane dynamics, phosphoinositide de-regulation contributes to various human diseases. In this review, we will focus on the newly emerging regulation of the PIKfyve complex, a phosphoinositide kinase that converts the endosomal phosphatidylinositol-3-phosphate [PI(3)P] to phosphatidylinositol-3,5-bisphosphate [PI(3,5)P2)], a low abundance phosphoinositide of outstanding importance for neuronal integrity and function. Loss of PIKfyve function is well known to result in neurodegeneration in both mouse models and human patients. Our recent work has surprisingly identified the amyloid precursor protein (APP), the central molecule in Alzheimer's disease aetiology, as a novel interaction partner of a subunit of the PIKfyve complex, Vac14. Furthermore, it has been shown that APP modulates PIKfyve function and PI(3,5)P2 dynamics, suggesting that the APP gene family functions as regulator of PI(3,5)P2 metabolism. The recent advances discussed in this review suggest a novel, unexpected, β-amyloid-independent mechanism for neurodegeneration in Alzheimer's disease.
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33
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Majumder P, Chakrabarti O. ESCRTs and associated proteins in lysosomal fusion with endosomes and autophagosomes. Biochem Cell Biol 2016; 94:443-450. [PMID: 27701906 DOI: 10.1139/bcb-2016-0099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Endolysosomal and autophagosomal degradation pathways are highly connected at various levels, sharing multiple molecular effectors that modulate them individually or simultaneously. These two lysosomal degradative pathways are primarily involved in the disposal of cargo internalized from the cell surface or long-lived proteins or aggregates and aged organelles present in the cytosol. Both of these pathways involve a number of carefully regulated vesicular fusion events that are dependent on ESCRT proteins. The ESCRT proteins especially ESCRT-I and III participate in the regulation of fusion events between autophagosome/amphisome and lysosome. Along with these, a number of functionally diverse ESCRT associated and regulatory proteins such as, endosomal PtdIns (3) P 5-kinase Fab1, ALIX, mahogunin ring finger 1, atrogin 1, syntaxin 17, ATG12-ATG3 complex, and protein kinase CK2α are involved in fusion events in either or both the lysosomal degradative pathways.
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Affiliation(s)
- Priyanka Majumder
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, West Bengal 700064, India.,Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, West Bengal 700064, India
| | - Oishee Chakrabarti
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, West Bengal 700064, India.,Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, West Bengal 700064, India
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34
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Krishna S, Palm W, Lee Y, Yang W, Bandyopadhyay U, Xu H, Florey O, Thompson CB, Overholtzer M. PIKfyve Regulates Vacuole Maturation and Nutrient Recovery following Engulfment. Dev Cell 2016; 38:536-47. [PMID: 27623384 PMCID: PMC5046836 DOI: 10.1016/j.devcel.2016.08.001] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 05/20/2016] [Accepted: 08/08/2016] [Indexed: 12/20/2022]
Abstract
The scavenging of extracellular macromolecules by engulfment can sustain cell growth in a nutrient-depleted environment. Engulfed macromolecules are contained within vacuoles that are targeted for lysosome fusion to initiate degradation and nutrient export. We have shown that vacuoles containing engulfed material undergo mTORC1-dependent fission that redistributes degraded cargo back into the endosomal network. Here we identify the lipid kinase PIKfyve as a regulator of an alternative pathway that distributes engulfed contents in support of intracellular macromolecular synthesis during macropinocytosis, entosis, and phagocytosis. We find that PIKfyve regulates vacuole size in part through its downstream effector, the cationic transporter TRPML1. Furthermore, PIKfyve promotes recovery of nutrients from vacuoles, suggesting a potential link between PIKfyve activity and lysosomal nutrient export. During nutrient depletion, PIKfyve activity protects Ras-mutant cells from starvation-induced cell death and supports their proliferation. These data identify PIKfyve as a critical regulator of vacuole maturation and nutrient recovery during engulfment.
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Affiliation(s)
- Shefali Krishna
- Gerstner Sloan Kettering Graduate School of Biomedical Sciences, New York, NY 10065, USA; Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Wilhelm Palm
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Yongchan Lee
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Wendy Yang
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Urmi Bandyopadhyay
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Haoxing Xu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 National Science Building (Kraus), 830 North University, Ann Arbor, MI 48109, USA
| | - Oliver Florey
- Signalling Programme, The Babraham Institute, Cambridge CB22 3AT, UK
| | - Craig B Thompson
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Michael Overholtzer
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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35
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Abstract
Most functions of eukaryotic cells are controlled by cellular membranes, which are not static entities but undergo frequent budding, fission, fusion, and sculpting reactions collectively referred to as membrane dynamics. Consequently, regulation of membrane dynamics is crucial for cellular functions. A key mechanism in such regulation is the reversible recruitment of cytosolic proteins or protein complexes to specific membranes at specific time points. To a large extent this recruitment is orchestrated by phosphorylated derivatives of the membrane lipid phosphatidylinositol, known as phosphoinositides. The seven phosphoinositides found in nature localize to distinct membrane domains and recruit distinct effectors, thereby contributing strongly to the maintenance of membrane identity. Many of the phosphoinositide effectors are proteins that control membrane dynamics, and in this review we discuss the functions of phosphoinositides in membrane dynamics during exocytosis, endocytosis, autophagy, cell division, cell migration, and epithelial cell polarity, with emphasis on protein effectors that are recruited by specific phosphoinositides during these processes.
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Affiliation(s)
- Kay O Schink
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Montebello, N-0379 Oslo, Norway; , .,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, N-0379 Oslo, Norway
| | - Kia-Wee Tan
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Montebello, N-0379 Oslo, Norway; , .,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, N-0379 Oslo, Norway
| | - Harald Stenmark
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Montebello, N-0379 Oslo, Norway; , .,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, N-0379 Oslo, Norway.,Centre of Molecular Inflammation Research, Faculty of Medicine, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
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36
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Compton LM, Ikonomov OC, Sbrissa D, Garg P, Shisheva A. Active vacuolar H+ ATPase and functional cycle of Rab5 are required for the vacuolation defect triggered by PtdIns(3,5)P2 loss under PIKfyve or Vps34 deficiency. Am J Physiol Cell Physiol 2016; 311:C366-77. [PMID: 27335171 DOI: 10.1152/ajpcell.00104.2016] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 06/17/2016] [Indexed: 01/12/2023]
Abstract
The two evolutionarily conserved mammalian lipid kinases Vps34 and PIKfyve are involved in an important physiological relationship, whereby the former produces phosphatidylinositol (PtdIns) 3P that is used as a substrate for PtdIns(3,5)P2 synthesis by the latter. Reduced production of PtdIns(3,5)P2 in proliferating mammalian cells is phenotypically manifested by the formation of multiple translucent cytoplasmic vacuoles, readily rescued upon exogenous delivery of PtdIns(3,5)P2 or overproduction of PIKfyve. Although the aberrant vacuolation phenomenon has been frequently used as a sensitive functional measure of localized PtdIns(3,5)P2 reduction, cellular factors governing the appearance of cytoplasmic vacuoles under PtdIns3P-PtdIns(3,5)P2 loss remain elusive. To gain further mechanistic insight about the vacuolation process following PtdIns(3,5)P2 reduction, in this study we sought for cellular mechanisms required for manifestation of the aberrant endomembrane vacuoles triggered by PIKfyve or Vps34 dysfunction. The latter was achieved by various means such as pharmacological inhibition, gene disruption, or dominant-interference in several proliferating mammalian cell types. We report here that inhibition of V-ATPase with bafilomycin A1 as well as inactivation of the GTP-GDP cycle of Rab5a GTPase phenotypically rescued or completely precluded the cytoplasmic vacuolization despite the continued presence of inactivated PIKfyve or Vps34. Bafilomycin A1 also restored the aberrant EEA1-positive endosomes, enlarged upon short PIKfyve inhibition with YM201636. Together, our work identifies for the first time that factors such as active V-ATPase or functional Rab5a cycle are acting coincidentally with the PtdIns(3,5)P2 reduction in triggering formation of aberrant cytoplasmic vacuoles under PIKfyve or Vps34 dysfunction.
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Affiliation(s)
- Lauren M Compton
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
| | - Ognian C Ikonomov
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
| | - Diego Sbrissa
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
| | - Puneet Garg
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Assia Shisheva
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
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37
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A cell-permeable tool for analysing APP intracellular domain function and manipulation of PIKfyve activity. Biosci Rep 2016; 36:BSR20160040. [PMID: 26934981 PMCID: PMC5293579 DOI: 10.1042/bsr20160040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 03/02/2016] [Indexed: 12/24/2022] Open
Abstract
The mechanisms for regulating PIKfyve complex activity are currently emerging. The PIKfyve complex, consisting of the phosphoinositide kinase PIKfyve (also known as FAB1), VAC14 and FIG4, is required for the production of phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2]. PIKfyve function is required for homoeostasis of the endo/lysosomal system and is crucially implicated in neuronal function and integrity, as loss of function mutations in the PIKfyve complex lead to neurodegeneration in mouse models and human patients. Our recent work has shown that the intracellular domain of the amyloid precursor protein (APP), a molecule central to the aetiology of Alzheimer's disease binds to VAC14 and enhances PIKfyve function. In the present study, we utilize this recent advance to create an easy-to-use tool for increasing PIKfyve activity in cells. We fused APP intracellular domain (AICD) to the HIV TAT domain, a cell-permeable peptide allowing proteins to penetrate cells. The resultant TAT-AICD fusion protein is cell permeable and triggers an increase in PI(3,5)P2 Using the PI(3,5)P2 specific GFP-ML1Nx2 probe, we show that cell-permeable AICD alters PI(3,5)P2 dynamics. TAT-AICD also provides partial protection from pharmacological inhibition of PIKfyve. All three lines of evidence show that the AICD activates the PIKfyve complex in cells, a finding that is important for our understanding of the mechanism of neurodegeneration in Alzheimer's disease.
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38
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A molecular mechanism to regulate lysosome motility for lysosome positioning and tubulation. Nat Cell Biol 2016; 18:404-17. [PMID: 26950892 PMCID: PMC4871318 DOI: 10.1038/ncb3324] [Citation(s) in RCA: 276] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 02/04/2016] [Indexed: 12/12/2022]
Abstract
To mediate the degradation of bio-macromolecules, lysosomes must traffic towards cargo-carrying vesicles for subsequent membrane fusion or fission. Mutations of the lysosomal Ca2+ channel TRPML1 cause lysosome storage disease (LSD) characterized by disordered lysosomal membrane trafficking in cells. Here we show that TRPML1 activity is required to promote Ca2+-dependent centripetal movement of lysosomes towards the perinuclear region, where autophagosomes accumulate, upon autophagy induction. ALG-2, an EF-hand-containing protein, serves as a lysosomal Ca2+ sensor that associates physically with the minus-end directed dynactin-dynein motor, while PI(3,5)P2, a lysosome-localized phosphoinositide, acts upstream of TRPML1. Furthermore, the PI(3,5)P2-TRPML1-ALG-2-dynein signaling is necessary for lysosome tubulation and reformation. In contrast, the TRPML1 pathway is not required for the perinuclear accumulation of lysosomes observed in many LSDs, which is instead likely caused by secondary cholesterol accumulation that constitutively activates Rab7-RILP-dependent retrograde transport. Collectively, Ca2+ release from lysosomes provides an on-demand mechanism regulating lysosome motility, positioning, and tubulation.
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39
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Deranieh RM, Shi Y, Tarsio M, Chen Y, McCaffery JM, Kane PM, Greenberg ML. Perturbation of the Vacuolar ATPase: A NOVEL CONSEQUENCE OF INOSITOL DEPLETION. J Biol Chem 2015; 290:27460-72. [PMID: 26324718 DOI: 10.1074/jbc.m115.683706] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Indexed: 11/06/2022] Open
Abstract
Depletion of inositol has profound effects on cell function and has been implicated in the therapeutic effects of drugs used to treat epilepsy and bipolar disorder. We have previously shown that the anticonvulsant drug valproate (VPA) depletes inositol by inhibiting myo-inositol-3-phosphate synthase, the enzyme that catalyzes the first and rate-limiting step of inositol biosynthesis. To elucidate the cellular consequences of inositol depletion, we screened the yeast deletion collection for VPA-sensitive mutants and identified mutants in vacuolar sorting and the vacuolar ATPase (V-ATPase). Inositol depletion caused by starvation of ino1Δ cells perturbed the vacuolar structure and decreased V-ATPase activity and proton pumping in isolated vacuolar vesicles. VPA compromised the dynamics of phosphatidylinositol 3,5-bisphosphate (PI3,5P2) and greatly reduced V-ATPase proton transport in inositol-deprived wild-type cells. Osmotic stress, known to increase PI3,5P2 levels, did not restore PI3,5P2 homeostasis nor did it induce vacuolar fragmentation in VPA-treated cells, suggesting that perturbation of the V-ATPase is a consequence of altered PI3,5P2 homeostasis under inositol-limiting conditions. This study is the first to demonstrate that inositol depletion caused by starvation of an inositol synthesis mutant or by the inositol-depleting drug VPA leads to perturbation of the V-ATPase.
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Affiliation(s)
- Rania M Deranieh
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - Yihui Shi
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - Maureen Tarsio
- the Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York 13210, and
| | - Yan Chen
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - J Michael McCaffery
- the Integrated Imaging Center, Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218
| | - Patricia M Kane
- the Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York 13210, and
| | - Miriam L Greenberg
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202,
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40
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PIKfyve mediates the motility of late endosomes and lysosomes in neuronal dendrites. Neurosci Lett 2015; 605:18-23. [PMID: 26232680 DOI: 10.1016/j.neulet.2015.07.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Revised: 07/14/2015] [Accepted: 07/20/2015] [Indexed: 12/22/2022]
Abstract
The endosome/lysosome system in the nervous system is critically important for a variety of neuronal functions such as neurite outgrowth, retrograde transport, and synaptic plasticity. In neurons, the endosome/lysosome system is crucial for the activity-dependent internalization of membrane proteins and contributes to the regulation of lipid level on the plasma membrane. Although homeostasis of membrane dynamics plays important roles in the properties of central nervous systems, it has not been elucidated how endosome/lysosome system is regulated. Here, we report that phosphatidylinositol 3-phosphate 5-kinase (PIKfyve) mediates the motility of late endosomes and lysosomes in neuronal dendrites. Endosomes and lysosomes are highly motile in resting neurons, however knockdown of PIKfyve led to a significant reduction in late endosomes and lysosomes motility. We also found that vesicle acidification is crucial for their motility and PIKfyve is associated with this process indirectly. These data suggest that PIKfyve mediates vesicle motility through the regulation of vesicle integrity in neurons.
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