1
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Bretou M, Sannerud R, Escamilla-Ayala A, Leroy T, Vrancx C, Van Acker ZP, Perdok A, Vermeire W, Vorsters I, Van Keymolen S, Maxson M, Pavie B, Wierda K, Eskelinen EL, Annaert W. Accumulation of APP C-terminal fragments causes endolysosomal dysfunction through the dysregulation of late endosome to lysosome-ER contact sites. Dev Cell 2024:S1534-5807(24)00199-0. [PMID: 38626765 DOI: 10.1016/j.devcel.2024.03.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/02/2023] [Accepted: 03/20/2024] [Indexed: 04/18/2024]
Abstract
Neuronal endosomal and lysosomal abnormalities are among the early changes observed in Alzheimer's disease (AD) before plaques appear. However, it is unclear whether distinct endolysosomal defects are temporally organized and how altered γ-secretase function or amyloid precursor protein (APP) metabolism contribute to these changes. Inhibiting γ-secretase chronically, in mouse embryonic fibroblast and hippocampal neurons, led to a gradual endolysosomal collapse initiated by decreased lysosomal calcium and increased cholesterol, causing downstream defects in endosomal recycling and maturation. This endolysosomal demise is γ-secretase dependent, requires membrane-tethered APP cytoplasmic domains, and is rescued by APP depletion. APP C-terminal fragments (CTFs) localized to late endosome/lysosome-endoplasmic reticulum contacts; an excess of APP-CTFs herein reduced lysosomal Ca2+ refilling from the endoplasmic reticulum, promoting cholesterol accretion. Tonic regulation by APP-CTFs provides a mechanistic explanation for their cellular toxicity: failure to timely degrade APP-CTFs sustains downstream signaling, instigating lysosomal dyshomeostasis, as observed in prodromal AD. This is the opposite of substrates such as Notch, which require intramembrane proteolysis to initiate signaling.
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Affiliation(s)
- Marine Bretou
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Ragna Sannerud
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | | | - Tom Leroy
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Céline Vrancx
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Zoë P Van Acker
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Anika Perdok
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Wendy Vermeire
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Inge Vorsters
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Sophie Van Keymolen
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Michelle Maxson
- Cell Biology Program, The Hospital for Sick Children, Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Benjamin Pavie
- VIB-BioImaging Core, VIB-Center for Brain and Disease Research, Leuven, Belgium
| | - Keimpe Wierda
- Electrophysiology Expertise Unit, VIB-Center for Brain and Disease Research, Leuven, Belgium
| | | | - Wim Annaert
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium.
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2
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Van Acker ZP, Perdok A, Hellemans R, North K, Vorsters I, Cappel C, Dehairs J, Swinnen JV, Sannerud R, Bretou M, Damme M, Annaert W. Phospholipase D3 degrades mitochondrial DNA to regulate nucleotide signaling and APP metabolism. Nat Commun 2023; 14:2847. [PMID: 37225734 DOI: 10.1038/s41467-023-38501-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 05/04/2023] [Indexed: 05/26/2023] Open
Abstract
Phospholipase D3 (PLD3) polymorphisms are linked to late-onset Alzheimer's disease (LOAD). Being a lysosomal 5'-3' exonuclease, its neuronal substrates remained unknown as well as how a defective lysosomal nucleotide catabolism connects to AD-proteinopathy. We identified mitochondrial DNA (mtDNA) as a major physiological substrate and show its manifest build-up in lysosomes of PLD3-defective cells. mtDNA accretion creates a degradative (proteolytic) bottleneck that presents at the ultrastructural level as a marked abundance of multilamellar bodies, often containing mitochondrial remnants, which correlates with increased PINK1-dependent mitophagy. Lysosomal leakage of mtDNA to the cytosol activates cGAS-STING signaling that upregulates autophagy and induces amyloid precursor C-terminal fragment (APP-CTF) and cholesterol accumulation. STING inhibition largely normalizes APP-CTF levels, whereas an APP knockout in PLD3-deficient backgrounds lowers STING activation and normalizes cholesterol biosynthesis. Collectively, we demonstrate molecular cross-talks through feedforward loops between lysosomal nucleotide turnover, cGAS-STING and APP metabolism that, when dysregulated, result in neuronal endolysosomal demise as observed in LOAD.
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Affiliation(s)
- Zoë P Van Acker
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Anika Perdok
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Ruben Hellemans
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Katherine North
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Inge Vorsters
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Cedric Cappel
- Laboratory for Molecular Cell Biology and Transgenic Research, Institute of Biochemistry, Christian-Albrechts-University Kiel, Otto-Hahn-Platz 9, Kiel, Germany
| | - Jonas Dehairs
- Laboratory of Lipid Metabolism & Cancer, Department of Oncology, KU Leuven, B-3000, Leuven, Belgium
| | - Johannes V Swinnen
- Laboratory of Lipid Metabolism & Cancer, Department of Oncology, KU Leuven, B-3000, Leuven, Belgium
| | - Ragna Sannerud
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Marine Bretou
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium
| | - Markus Damme
- Laboratory for Molecular Cell Biology and Transgenic Research, Institute of Biochemistry, Christian-Albrechts-University Kiel, Otto-Hahn-Platz 9, Kiel, Germany
| | - Wim Annaert
- Laboratory for Membrane Trafficking, VIB Center for Brain & Disease Research, Herestraat 49, box 602, Leuven, Belgium.
- Department of Neurosciences, KU Leuven, Herestraat 49, box 602, Leuven, Belgium.
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3
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Perdok A, Sannerud R, Vegh Z, Serneels L, Annaert W. Elucidating the molecular basis of altered Presenilin 2 expression on Alzheimer’s disease pathology. Alzheimers Dement 2022. [DOI: 10.1002/alz.064556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Anika Perdok
- VIB‐KU Leuven Center for Brain & Disease Research Leuven Belgium
| | - Ragna Sannerud
- VIB‐KU Leuven Center for Brain & Disease Research Leuven Belgium
| | | | | | - Wim Annaert
- VIB‐KU Leuven Center for Brain & Disease Research Leuven Belgium
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4
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Van Acker ZP, Bretou M, Sannerud R, Damme M, Annaert W. Altered PLD3 exonuclease activity impacts on lysosomal and mitochondrial homeostasis. Alzheimers Dement 2022. [DOI: 10.1002/alz.063567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Zoë P. Van Acker
- VIB‐KU Leuven Center for Brain & Disease Research Leuven Belgium
| | - Marine Bretou
- VIB‐KU Leuven Center for Brain & Disease Research Leuven Belgium
| | - Ragna Sannerud
- VIB‐KU Leuven Center for Brain & Disease Research Leuven Belgium
| | - Markus Damme
- Christian‐Albrechts‐Universitaet Kiel Kiel Germany
| | - Wim Annaert
- VIB‐KU Leuven Center for Brain & Disease Research Leuven Belgium
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5
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Van Acker ZP, Bretou M, Sannerud R, Damme M, Annaert W. Deficiency of the lysosomal exonuclease PLD3 impacts the degradative route. Alzheimers Dement 2021. [DOI: 10.1002/alz.050868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Zoë P. Van Acker
- VIB‐KU Leuven Center for Brain & Disease Research Leuven Belgium
| | - Marine Bretou
- VIB‐KU Leuven Center for Brain & Disease Research Leuven Belgium
| | - Ragna Sannerud
- VIB‐KU Leuven Center for Brain & Disease Research Leuven Belgium
| | - Markus Damme
- Christian‐Albrechts‐Universitaet Kiel Kiel Germany
| | - Wim Annaert
- VIB‐KU Leuven Center for Brain & Disease Research Leuven Belgium
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6
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Wouters R, Michiels C, Sannerud R, Kleizen B, Dillen K, Vermeire W, Ayala AE, Demedts D, Schekman R, Annaert W. Assembly of γ-secretase occurs through stable dimers after exit from the endoplasmic reticulum. J Cell Biol 2021; 220:212501. [PMID: 34292306 PMCID: PMC8302450 DOI: 10.1083/jcb.201911104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/29/2020] [Accepted: 06/07/2021] [Indexed: 01/22/2023] Open
Abstract
γ-Secretase affects many physiological processes through targeting >100 substrates; malfunctioning links γ-secretase to cancer and Alzheimer’s disease. The spatiotemporal regulation of its stoichiometric assembly remains unresolved. Fractionation, biochemical assays, and imaging support prior formation of stable dimers in the ER, which, after ER exit, assemble into full complexes. In vitro ER budding shows that none of the subunits is required for the exit of others. However, knockout of any subunit leads to the accumulation of incomplete subcomplexes in COPII vesicles. Mutating a DPE motif in presenilin 1 (PSEN1) abrogates ER exit of PSEN1 and PEN-2 but not nicastrin. We explain this by the preferential sorting of PSEN1 and nicastrin through Sec24A and Sec24C/D, respectively, arguing against full assembly before ER exit. Thus, dimeric subcomplexes aided by Sec24 paralog selectivity support a stepwise assembly of γ-secretase, controlling final levels in post-Golgi compartments.
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Affiliation(s)
- Rosanne Wouters
- Laboratory for Membrane Trafficking, Vlaams Instituut voor Biotechnologie Center for Brain and Disease Research, Katholieke Universiteit Leuven, Leuven, Belgium.,Department of Neurosciences, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Christine Michiels
- Laboratory for Membrane Trafficking, Vlaams Instituut voor Biotechnologie Center for Brain and Disease Research, Katholieke Universiteit Leuven, Leuven, Belgium.,Department of Neurosciences, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Ragna Sannerud
- Laboratory for Membrane Trafficking, Vlaams Instituut voor Biotechnologie Center for Brain and Disease Research, Katholieke Universiteit Leuven, Leuven, Belgium.,Department of Neurosciences, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Bertrand Kleizen
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Katleen Dillen
- Laboratory for Membrane Trafficking, Vlaams Instituut voor Biotechnologie Center for Brain and Disease Research, Katholieke Universiteit Leuven, Leuven, Belgium.,Department of Neurosciences, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Wendy Vermeire
- Laboratory for Membrane Trafficking, Vlaams Instituut voor Biotechnologie Center for Brain and Disease Research, Katholieke Universiteit Leuven, Leuven, Belgium.,Department of Neurosciences, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Abril Escamilla Ayala
- Vlaams Instituut voor Biotechnologie BioImaging Core, Vlaams Instituut voor Biotechnologie Center for Brain and Disease Research, Leuven, Belgium
| | - David Demedts
- Laboratory for Membrane Trafficking, Vlaams Instituut voor Biotechnologie Center for Brain and Disease Research, Katholieke Universiteit Leuven, Leuven, Belgium.,Department of Neurosciences, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Randy Schekman
- Department of Molecular and Cell Biology and Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA
| | - Wim Annaert
- Laboratory for Membrane Trafficking, Vlaams Instituut voor Biotechnologie Center for Brain and Disease Research, Katholieke Universiteit Leuven, Leuven, Belgium.,Department of Neurosciences, Katholieke Universiteit Leuven, Leuven, Belgium
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7
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Hamouda NN, Van den Haute C, Vanhoutte R, Sannerud R, Azfar M, Mayer R, Cortés Calabuig Á, Swinnen JV, Agostinis P, Baekelandt V, Annaert W, Impens F, Verhelst SHL, Eggermont J, Martin S, Vangheluwe P. ATP13A3 is a major component of the enigmatic mammalian polyamine transport system. J Biol Chem 2020; 296:100182. [PMID: 33310703 PMCID: PMC7948421 DOI: 10.1074/jbc.ra120.013908] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 11/27/2020] [Accepted: 12/11/2020] [Indexed: 12/13/2022] Open
Abstract
Polyamines, such as putrescine, spermidine, and spermine, are physiologically important polycations, but the transporters responsible for their uptake in mammalian cells remain poorly characterized. Here, we reveal a new component of the mammalian polyamine transport system using CHO-MG cells, a widely used model to study alternative polyamine uptake routes and characterize polyamine transport inhibitors for therapy. CHO-MG cells present polyamine uptake deficiency and resistance to a toxic polyamine biosynthesis inhibitor methylglyoxal bis-(guanylhydrazone) (MGBG), but the molecular defects responsible for these cellular characteristics remain unknown. By genome sequencing of CHO-MG cells, we identified mutations in an unexplored gene, ATP13A3, and found disturbed mRNA and protein expression. ATP13A3 encodes for an orphan P5B-ATPase (ATP13A3), a P-type transport ATPase that represents a candidate polyamine transporter. Interestingly, ATP13A3 complemented the putrescine transport deficiency and MGBG resistance of CHO-MG cells, whereas its knockdown in WT cells induced a CHO-MG phenotype demonstrated as a decrease in putrescine uptake and MGBG sensitivity. Taken together, our findings identify ATP13A3, which has been previously genetically linked with pulmonary arterial hypertension, as a major component of the mammalian polyamine transport system that confers sensitivity to MGBG.
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Affiliation(s)
- Norin Nabil Hamouda
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Chris Van den Haute
- Laboratory for Neurobiology and Gene Therapy, Department of Neurosciences, KU Leuven, Leuven, Belgium; Leuven Viral Vector Core, KU Leuven, Leuven, Belgium
| | - Roeland Vanhoutte
- Laboratory of Chemical Biology, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Ragna Sannerud
- VIB-KU Leuven Laboratory of Membrane Trafficking, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Mujahid Azfar
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Rupert Mayer
- Department for Biomolecular Medicine, VIB Center for Medical Biotechnology, VIB Proteomics Core, Ghent University, Ghent, Belgium
| | | | - Johannes V Swinnen
- Laboratory of Lipid Metabolism and Cancer, Department of Oncology, LKI - Leuven Cancer Institute, KU Leuven, Leuven, Belgium
| | - Patrizia Agostinis
- Laboratory of Cell Death Research & Therapy, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium; Department of Oncology, VIB-KU Leuven Center for Cancer Biology, KU Leuven, Leuven, Belgium
| | - Veerle Baekelandt
- Laboratory for Neurobiology and Gene Therapy, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Wim Annaert
- VIB-KU Leuven Laboratory of Membrane Trafficking, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Francis Impens
- Department for Biomolecular Medicine, VIB Center for Medical Biotechnology, VIB Proteomics Core, Ghent University, Ghent, Belgium
| | - Steven H L Verhelst
- Laboratory of Chemical Biology, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium; Chemical Proteomics, Leibniz Institute for Analytical Sciences ISAS, Dortmund, Germany
| | - Jan Eggermont
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Shaun Martin
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Peter Vangheluwe
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.
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8
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Wouters R, Michiels C, Kleizen B, Dillen K, Vermeire W, Demedts D, Sannerud R, Schekman R, Annaert W. SEC24 isoform specificity regulates the assembly of γ‐secretase from dimeric subcomplexes. Alzheimers Dement 2020. [DOI: 10.1002/alz.042844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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9
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Bretou M, Sannerud R, Vermeire W, Demedts D, Annaert W. Contribution of Alzheimer’s disease risk genes in the maintenance of endolysosomal transport regulation. Alzheimers Dement 2020. [DOI: 10.1002/alz.042967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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10
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Escamilla-Ayala A, Wouters R, Sannerud R, Annaert W. Contribution of the Presenilins in the cell biology, structure and function of γ-secretase. Semin Cell Dev Biol 2020; 105:12-26. [DOI: 10.1016/j.semcdb.2020.02.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 02/06/2020] [Accepted: 02/17/2020] [Indexed: 01/25/2023]
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11
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Escamilla-Ayala AA, Sannerud R, Mondin M, Poersch K, Vermeire W, Paparelli L, Berlage C, Koenig M, Chavez-Gutierrez L, Ulbrich MH, Munck S, Mizuno H, Annaert W. Super-resolution microscopy reveals majorly mono- and dimeric presenilin1/γ-secretase at the cell surface. eLife 2020; 9:56679. [PMID: 32631487 PMCID: PMC7340497 DOI: 10.7554/elife.56679] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 06/15/2020] [Indexed: 12/17/2022] Open
Abstract
γ-Secretase is a multi-subunit enzyme whose aberrant activity is associated with Alzheimer’s disease and cancer. While its structure is atomically resolved, γ-secretase localization in the membrane in situ relies mostly on biochemical data. Here, we combined fluorescent tagging of γ-secretase subunits with super-resolution microscopy in fibroblasts. Structured illumination microscopy revealed single γ-secretase complexes with a monodisperse distribution and in a 1:1 stoichiometry of PSEN1 and nicastrin subunits. In living cells, sptPALM revealed PSEN1/γ-secretase mainly with directed motility and frequenting ‘hotspots’ or high track-density areas that are sensitive to γ-secretase inhibitors. We visualized γ-secretase association with substrates like amyloid precursor protein and N-cadherin, but not with its sheddases ADAM10 or BACE1 at the cell surface, arguing against pre-formed megadalton complexes. Nonetheless, in living cells PSEN1/γ-secretase transiently visits ADAM10 hotspots. Our results highlight the power of super-resolution microscopy for the study of γ-secretase distribution and dynamics in the membrane.
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Affiliation(s)
- Abril Angélica Escamilla-Ayala
- Laboratory for Membrane Trafficking, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Ragna Sannerud
- Laboratory for Membrane Trafficking, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Magali Mondin
- Bordeaux Imaging Center, UMS 3420, CNRS-University of Bordeaux, US4 INSERM, Bordeaux, France
| | - Karin Poersch
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Wendy Vermeire
- Laboratory for Membrane Trafficking, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Laura Paparelli
- Laboratory for Membrane Trafficking, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium.,VIB Bio Imaging Core, Leuven, Belgium
| | - Caroline Berlage
- Einstein Center for Neurosciences, NeuroCure Cluster of Excellence, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | | | - Lucia Chavez-Gutierrez
- Department of Neurosciences, KU Leuven, Leuven, Belgium.,Laboratory of Proteolytic Mechanisms in Neurodegeneration, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
| | - Maximilian H Ulbrich
- Institute of Internal Medicine IV, Medical Center of the University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany
| | - Sebastian Munck
- Department of Neurosciences, KU Leuven, Leuven, Belgium.,VIB Bio Imaging Core, Leuven, Belgium
| | - Hideaki Mizuno
- Laboratory of Biomolecular Network Dynamics, Biochemistry, Molecular and Structural Biology Section, KU Leuven, Heverlee, Belgium
| | - Wim Annaert
- Laboratory for Membrane Trafficking, VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
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12
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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. Correction: The PIKfyve complex regulates the early melanosome homeostasis required for physiological amyloid formation (doi:10.1242/jcs.229500). J Cell Sci 2019; 132:132/6/jcs231746. [PMID: 30923131 DOI: 10.1242/jcs.231746] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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13
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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14
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Guix FX, Sannerud R, Berditchevski F, Arranz AM, Horré K, Snellinx A, Thathiah A, Saido T, Saito T, Rajesh S, Overduin M, Kumar-Singh S, Radaelli E, Corthout N, Colombelli J, Tosi S, Munck S, Salas IH, Annaert W, De Strooper B. Tetraspanin 6: a pivotal protein of the multiple vesicular body determining exosome release and lysosomal degradation of amyloid precursor protein fragments. Mol Neurodegener 2017; 12:25. [PMID: 28279219 PMCID: PMC5345265 DOI: 10.1186/s13024-017-0165-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 02/22/2017] [Indexed: 12/18/2022] Open
Abstract
Background The mechanisms behind Aβ-peptide accumulation in non-familial Alzheimer’s disease (AD) remain elusive. Proteins of the tetraspanin family modulate Aβ production by interacting to γ-secretase. Methods We searched for tetraspanins with altered expression in AD brains. The function of the selected tetraspanin was studied in vitro and the physiological relevance of our findings was confirmed in vivo. Results Tetraspanin-6 (TSPAN6) is increased in AD brains and overexpression in cells exerts paradoxical effects on Amyloid Precursor Protein (APP) metabolism, increasing APP-C-terminal fragments (APP-CTF) and Aβ levels at the same time. TSPAN6 affects autophagosome-lysosomal fusion slowing down the degradation of APP-CTF. TSPAN6 recruits also the cytosolic, exosome-forming adaptor syntenin which increases secretion of exosomes that contain APP-CTF. Conclusions TSPAN6 is a key player in the bifurcation between lysosomal-dependent degradation and exosome mediated secretion of APP-CTF. This corroborates the central role of the autophagosomal/lysosomal pathway in APP metabolism and shows that TSPAN6 is a crucial player in APP-CTF turnover. Electronic supplementary material The online version of this article (doi:10.1186/s13024-017-0165-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Francesc X Guix
- VIB Center for Brain and Disease research - VIB, Leuven, Belgium. .,Center of Human Genetics and Leuven Institute for Neurodegenerative Diseases (LIND), KULeuven, Leuven, Gasthuisberg O&N, Belgium.
| | - Ragna Sannerud
- VIB Center for Brain and Disease research - VIB, Leuven, Belgium.,Center of Human Genetics and Leuven Institute for Neurodegenerative Diseases (LIND), KULeuven, Leuven, Gasthuisberg O&N, Belgium
| | - Fedor Berditchevski
- School of Cancer Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Amaia M Arranz
- VIB Center for Brain and Disease research - VIB, Leuven, Belgium.,Center of Human Genetics and Leuven Institute for Neurodegenerative Diseases (LIND), KULeuven, Leuven, Gasthuisberg O&N, Belgium
| | - Katrien Horré
- VIB Center for Brain and Disease research - VIB, Leuven, Belgium.,Center of Human Genetics and Leuven Institute for Neurodegenerative Diseases (LIND), KULeuven, Leuven, Gasthuisberg O&N, Belgium
| | - An Snellinx
- VIB Center for Brain and Disease research - VIB, Leuven, Belgium.,Center of Human Genetics and Leuven Institute for Neurodegenerative Diseases (LIND), KULeuven, Leuven, Gasthuisberg O&N, Belgium
| | - Amantha Thathiah
- Department of Neurobiology, University of Pittsburgh Brain Institute, Pittsburgh Institute for Neurodegenerative Disease, University of Pittsburgh School of Medicine, Biomedical Science Tower 3, Room 6062, 3501 Fifth Avenue, Pittsburgh, PA, 15213-3301, USA
| | - Takaomi Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Brain Science Institute, Wako-shi, 351-0198, Saitama, Japan
| | - Takashi Saito
- Laboratory for Proteolytic Neuroscience, RIKEN Brain Science Institute, Wako-shi, 351-0198, Saitama, Japan
| | - Sundaresan Rajesh
- School of Cancer Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Michael Overduin
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Canada
| | - Samir Kumar-Singh
- Molecular Pathology Group, Cell Biology & Histology, Faculty of Medicine, University of Antwerp, Antwerp, Belgium
| | - Enrico Radaelli
- VIB Center for Brain and Disease research - VIB, Leuven, Belgium.,Center of Human Genetics and Leuven Institute for Neurodegenerative Diseases (LIND), KULeuven, Leuven, Gasthuisberg O&N, Belgium
| | - Nikky Corthout
- VIB Center for Brain and Disease research - VIB, Leuven, Belgium.,Center of Human Genetics and Leuven Institute for Neurodegenerative Diseases (LIND), KULeuven, Leuven, Gasthuisberg O&N, Belgium
| | - Julien Colombelli
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, c. Baldiri Reixac 10, 08028, Barcelona, Spain
| | - Sébastien Tosi
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, c. Baldiri Reixac 10, 08028, Barcelona, Spain
| | - Sebastian Munck
- VIB Center for Brain and Disease research - VIB, Leuven, Belgium.,Center of Human Genetics and Leuven Institute for Neurodegenerative Diseases (LIND), KULeuven, Leuven, Gasthuisberg O&N, Belgium
| | - Isabel H Salas
- VIB Center for Brain and Disease research - VIB, Leuven, Belgium.,Center of Human Genetics and Leuven Institute for Neurodegenerative Diseases (LIND), KULeuven, Leuven, Gasthuisberg O&N, Belgium
| | - Wim Annaert
- VIB Center for Brain and Disease research - VIB, Leuven, Belgium.,Center of Human Genetics and Leuven Institute for Neurodegenerative Diseases (LIND), KULeuven, Leuven, Gasthuisberg O&N, Belgium
| | - Bart De Strooper
- VIB Center for Brain and Disease research - VIB, Leuven, Belgium. .,Center of Human Genetics and Leuven Institute for Neurodegenerative Diseases (LIND), KULeuven, Leuven, Gasthuisberg O&N, Belgium. .,Dementia Research Institute (DRI-UK), University College London, Queen Square, WC1N 3BG, London, UK.
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15
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Affiliation(s)
- Ragna Sannerud
- Laboratory for Membrane Trafficking, VIB - Center for Brain & Disease Research & KU Leuven, Gasthuisberg Leuven, Belgium
| | - Wim Annaert
- Laboratory for Membrane Trafficking, VIB - Center for Brain & Disease Research & KU Leuven, Gasthuisberg Leuven, Belgium
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16
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Paparelli L, Corthout N, Pavie B, Wakefield DL, Sannerud R, Jovanovic-Talisman T, Annaert W, Munck S. Inhomogeneity Based Characterization of Distribution Patterns on the Plasma Membrane. PLoS Comput Biol 2016; 12:e1005095. [PMID: 27603951 PMCID: PMC5014321 DOI: 10.1371/journal.pcbi.1005095] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 08/02/2016] [Indexed: 12/04/2022] Open
Abstract
Cell surface protein and lipid molecules are organized in various patterns: randomly, along gradients, or clustered when segregated into discrete micro- and nano-domains. Their distribution is tightly coupled to events such as polarization, endocytosis, and intracellular signaling, but challenging to quantify using traditional techniques. Here we present a novel approach to quantify the distribution of plasma membrane proteins and lipids. This approach describes spatial patterns in degrees of inhomogeneity and incorporates an intensity-based correction to analyze images with a wide range of resolutions; we have termed it Quantitative Analysis of the Spatial distributions in Images using Mosaic segmentation and Dual parameter Optimization in Histograms (QuASIMoDOH). We tested its applicability using simulated microscopy images and images acquired by widefield microscopy, total internal reflection microscopy, structured illumination microscopy, and photoactivated localization microscopy. We validated QuASIMoDOH, successfully quantifying the distribution of protein and lipid molecules detected with several labeling techniques, in different cell model systems. We also used this method to characterize the reorganization of cell surface lipids in response to disrupted endosomal trafficking and to detect dynamic changes in the global and local organization of epidermal growth factor receptors across the cell surface. Our findings demonstrate that QuASIMoDOH can be used to assess protein and lipid patterns, quantifying distribution changes and spatial reorganization at the cell surface. An ImageJ/Fiji plugin of this analysis tool is provided. Plasma membrane organization is fundamental to cellular signaling, transport of molecules, and cell adhesion. To achieve this, plasma membrane proteins and lipids are spatially organized: they form clusters, aggregate in signaling platforms, distribute into gradients on polarized cells, or randomly distribute across the membrane. It is also clear that these organizations can be affected in various contexts. For example, in aging or neurodegenerative diseases, the composition of the plasma membrane is altered and, consequently, the protein and lipid distributions in the membrane fluctuate. In addition, cancer progression is characterized by changes in cellular polarity, lipid content, and the redistribution of cell surface receptors and adhesion molecules. Here we have developed a method to quantify such alterations that, unlike current tools, is compatible with diverse types of cellular organization, including polarity. Our tool can be employed to screen for changes in a straightforward manner and to elucidate distributions of cell surface components in different disciplines, ranging from neurobiology to cancer research.
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Affiliation(s)
- Laura Paparelli
- VIB Bio Imaging Core, Herestraat, Leuven, Belgium
- Laboratory of Membrane Trafficking, Department of Human Genetics, KU Leuven, Herestraat, Leuven, Belgium
- VIB Center for the Biology of Disease, KU Leuven, Herestraat, Leuven, Belgium
| | - Nikky Corthout
- VIB Bio Imaging Core, Herestraat, Leuven, Belgium
- VIB Center for the Biology of Disease, KU Leuven, Herestraat, Leuven, Belgium
- VIB, LiMoNe, Herestraat, Leuven, Belgium
| | - Benjamin Pavie
- VIB Bio Imaging Core, Herestraat, Leuven, Belgium
- VIB Center for the Biology of Disease, KU Leuven, Herestraat, Leuven, Belgium
| | - Devin L. Wakefield
- Department of Molecular Medicine, Beckman Research Institute of the City of Hope Comprehensive Cancer Center, Duarte, California, United States of America
| | - Ragna Sannerud
- Laboratory of Membrane Trafficking, Department of Human Genetics, KU Leuven, Herestraat, Leuven, Belgium
- VIB Center for the Biology of Disease, KU Leuven, Herestraat, Leuven, Belgium
| | - Tijana Jovanovic-Talisman
- Department of Molecular Medicine, Beckman Research Institute of the City of Hope Comprehensive Cancer Center, Duarte, California, United States of America
| | - Wim Annaert
- Laboratory of Membrane Trafficking, Department of Human Genetics, KU Leuven, Herestraat, Leuven, Belgium
- VIB Center for the Biology of Disease, KU Leuven, Herestraat, Leuven, Belgium
- * E-mail: (WA); Sebastian@ (SM)
| | - Sebastian Munck
- VIB Bio Imaging Core, Herestraat, Leuven, Belgium
- VIB Center for the Biology of Disease, KU Leuven, Herestraat, Leuven, Belgium
- VIB, LiMoNe, Herestraat, Leuven, Belgium
- * E-mail: (WA); Sebastian@ (SM)
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17
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Jurisch-Yaksi N, Sannerud R, Annaert W. A fast growing spectrum of biological functions of γ-secretase in development and disease. Biochim Biophys Acta 2013; 1828:2815-27. [PMID: 24099003 DOI: 10.1016/j.bbamem.2013.04.016] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 04/03/2013] [Accepted: 04/11/2013] [Indexed: 12/17/2022]
Abstract
γ-secretase, which assembles as a tetrameric complex, is an aspartyl protease that proteolytically cleaves substrate proteins within their membrane-spanning domain; a process also known as regulated intramembrane proteolysis (RIP). RIP regulates signaling pathways by abrogating or releasing signaling molecules. Since the discovery, already >15 years ago, of its catalytic component, presenilin, and even much earlier with the identification of amyloid precursor protein as its first substrate, γ-secretase has been commonly associated with Alzheimer's disease. However, starting with Notch and thereafter a continuously increasing number of novel substrates, γ-secretase is becoming linked to an equally broader range of biological processes. This review presents an updated overview of the current knowledge on the diverse molecular mechanisms and signaling pathways controlled by γ-secretase, with a focus on organ development, homeostasis and dysfunction. This article is part of a Special Issue entitled: Intramembrane Proteases.
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Affiliation(s)
- Nathalie Jurisch-Yaksi
- Laboratory for Membrane Trafficking, VIB-Center for the Biology of Disease & Department for Human Genetics (KU Leuven), Leuven, Belgium
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18
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Esselens C, Sannerud R, Gallardo R, Baert V, Kaden D, Serneels L, De Strooper B, Rousseau F, Multhaup G, Schymkowitz J, Langedijk JPM, Annaert W. Peptides based on the presenilin-APP binding domain inhibit APP processing and Aβ production through interfering with the APP transmembrane domain. FASEB J 2012; 26:3765-78. [PMID: 22661005 DOI: 10.1096/fj.11-201368] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Presenilins (PSENs) form the catalytic component of the γ-secretase complex, responsible for intramembrane proteolysis of amyloid precursor protein (APP) and Notch, among many other membrane proteins. Previously, we identified a PSEN1-binding domain in APP, encompassing half of the transmembrane domain following the amyloid β (Aβ) sequence. Based on this, we designed peptides mimicking this interaction domain with the aim to selectively block APP processing and Aβ generation through interfering with enzyme-substrate binding. We identified a peptide sequence that, when fused to a virally derived translocation peptide, significantly lowered Aβ production (IC(50): 317 nM) in cell-free and cell-based assays using APP-carboxy terminal fragment as a direct γ-secretase substrate. Being derived from the APP sequence, this inhibitory peptide did not affect NotchΔE γ-cleavage, illustrating specificity and potential therapeutic value. In cell-based assays, the peptide strongly suppressed APP shedding, demonstrating that it exerts the inhibitory effect already upstream of γ-secretase, most likely through steric hindrance.
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Affiliation(s)
- Cary Esselens
- Laboratory for Membrane Trafficking, Center for Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium
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19
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Munck S, Miskiewicz K, Sannerud R, Menchon SA, Jose L, Heintzmann R, Verstreken P, Annaert W. Sub-diffraction imaging on standard microscopes through Photobleaching Microscopy with non-linear Processing. J Cell Sci 2012; 125:2257-66. [DOI: 10.1242/jcs.098939] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Discerning organelles and molecules at nanometer resolution is revolutionizing biological sciences. However, such technology is still limitedly available for many cell biologists. We present here a novel approach using Photobleaching Microscopy with non-linear Processing (PiMP) for sub-diffraction imaging. Bleaching fluorophores both within the single molecule regime and beyond allows visualizing stochastic representations of sub-populations of fluorophores by imaging the same region over time. Our method is based on enhancing probable positions of the fluorophores underlying the images. The random nature of the bleached fluorophores is assessed by calculating the deviation of the local actual bleached fluorescence intensity to the average bleach expectation as given by the overall decay of intensity. Subtracting measured from estimated decay images yields differential images. Non-linear enhancement of maxima in these diffraction limited differential images approximates the positions of the underlying structure. Summing many such processed differential images yields a super-resolution PiMP image. PiMP allows multi-color, three-dimensional sub-diffraction imaging of cells and tissues using common fluorophores and can be implemented on standard widefield or confocal systems.
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20
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Zhou L, Chávez-Gutiérrez L, Bockstael K, Sannerud R, Annaert W, May PC, Karran E, De Strooper B. Inhibition of beta-secretase in vivo via antibody binding to unique loops (D and F) of BACE1. J Biol Chem 2011; 286:8677-8687. [PMID: 21209097 DOI: 10.1074/jbc.m110.194860] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
β-Secretase (BACE1) is an attractive drug target for Alzheimer disease. However, the design of clinical useful inhibitors targeting its active site has been extremely challenging. To identify alternative drug targeting sites we have generated a panel of BACE1 monoclonal antibodies (mAbs) that interfere with BACE1 activity in various assays and determined their binding epitopes. mAb 1A11 inhibited BACE1 in vitro using a large APP sequence based substrate (IC(50) ∼0.76 nm), in primary neurons (EC(50) ∼1.8 nm), and in mouse brain after stereotactic injection. Paradoxically, mAb 1A11 increased BACE1 activity in vitro when a short synthetic peptide was used as substrate, indicating that mAb 1A11 does not occupy the active-site. Epitope mapping revealed that mAb 1A11 binds to adjacent loops D and F, which together with nearby helix A, distinguishes BACE1 from other aspartyl proteases. Interestingly, mutagenesis of loop F and helix A decreased or increased BACE1 activity, identifying them as enzymatic regulatory elements and as potential alternative sites for inhibitor design. In contrast, mAb 5G7 was a potent BACE1 inhibitor in cell-free enzymatic assays (IC(50) ∼0.47 nm) but displayed no inhibitory effect in primary neurons. Its epitope, a surface helix 299-312, is inaccessible in membrane-anchored BACE1. Remarkably, mutagenesis of helix 299-312 strongly reduced BACE1 ectodomain shedding, suggesting that this helix plays a role in BACE1 cellular biology. In conclusion, this study generated highly selective and potent BACE1 inhibitory mAbs, which recognize unique structural and functional elements in BACE1, and uncovered interesting alternative sites on BACE1 that could become targets for drug development.
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Affiliation(s)
- Lujia Zhou
- From the Department of Molecular and Developmental Genetics, VIB and; the Center for Human Genetics, KULeuven, 3000 Leuven, Belgium
| | - Lucia Chávez-Gutiérrez
- From the Department of Molecular and Developmental Genetics, VIB and; the Center for Human Genetics, KULeuven, 3000 Leuven, Belgium
| | - Katrijn Bockstael
- From the Department of Molecular and Developmental Genetics, VIB and; the Center for Human Genetics, KULeuven, 3000 Leuven, Belgium
| | - Ragna Sannerud
- From the Department of Molecular and Developmental Genetics, VIB and; the Center for Human Genetics, KULeuven, 3000 Leuven, Belgium
| | - Wim Annaert
- From the Department of Molecular and Developmental Genetics, VIB and; the Center for Human Genetics, KULeuven, 3000 Leuven, Belgium
| | - Patrick C May
- the Neuroscience Discovery Research, Lilly Research Laboratories, Eli Lilly and Co., Indianapolis, Indiana 46285, and
| | - Eric Karran
- Johnson and Johnson Pharmaceutical Research and Development, 2340 Beerse, Belgium
| | - Bart De Strooper
- From the Department of Molecular and Developmental Genetics, VIB and; the Center for Human Genetics, KULeuven, 3000 Leuven, Belgium,.
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21
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Marie M, Dale HA, Sannerud R, Saraste J. The function of the intermediate compartment in pre-Golgi trafficking involves its stable connection with the centrosome. Mol Biol Cell 2009; 20:4458-70. [PMID: 19710425 PMCID: PMC2762134 DOI: 10.1091/mbc.e08-12-1229] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 08/18/2009] [Accepted: 08/19/2009] [Indexed: 01/03/2023] Open
Abstract
Because the functional borders of the intermediate compartment (IC) are not well defined, the spatial map of the transport machineries operating between the endoplasmic reticulum (ER) and the Golgi apparatus remains incomplete. Our previous studies showed that the IC consists of interconnected vacuolar and tubular parts with specific roles in pre-Golgi trafficking. Here, using live cell imaging, we demonstrate that the tubules containing the GTPase Rab1A create a long-lived membrane compartment around the centrosome. Separation of this pericentrosomal domain of the IC from the Golgi ribbon, due to centrosome motility, revealed that it contains a distinct pool of COPI coats and acts as a temperature-sensitive way station in post-ER trafficking. However, unlike the Golgi, the pericentrosomal IC resists the disassembly of COPI coats by brefeldin A, maintaining its juxtaposition with the endocytic recycling compartment, and operation as the focal point of a dynamic tubular network that extends to the cell periphery. These results provide novel insight into the compartmental organization of the secretory pathway and Golgi biogenesis. Moreover, they reveal a direct functional connection between the IC and the endosomal system, which evidently contributes to unconventional transport of the cystic fibrosis transmembrane conductance regulator to the cell surface.
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Affiliation(s)
- Michaël Marie
- Department of Biomedicine and Molecular Imaging Center, University of Bergen, N-5009 Bergen, Norway
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22
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Sannerud R, Annaert W. Trafficking, a key player in regulated intramembrane proteolysis. Semin Cell Dev Biol 2009; 20:183-90. [DOI: 10.1016/j.semcdb.2008.11.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 11/05/2008] [Accepted: 11/07/2008] [Indexed: 01/03/2023]
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Abstract
Cholesterol, certain lipids, membrane-bound and soluble proteins, as well as viruses that are synthesized in the endoplasmic reticulum (ER), reach the plasma membrane (PM) via non-classical pathway(s) that remain poorly understood. Typical for this transport is (i) its insensitivity to brefeldin A (BFA), which dissociates selected coat complexes from membranes, resulting in the disassembly of the Golgi apparatus; (ii) its rapid kinetics as compared to the classical secretory pathway; and (iii) its role in the trafficking of lipid raft components. Based on results showing that the intermediate compartment (IC) at the ER-Golgi boundary constitutes a stable tubular network that maintains its dynamics in the presence of BFA, we propose that two bidirectional Golgi-bypass pathways to the PM exist, a direct route from early IC elements, and another, reminiscent of the yeast secretory pathway, from late IC elements via the endosomal system. These pathways have implications for the organization of the secretory processes in different cell types.
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Affiliation(s)
- M Marie
- Section of Anatomy and Cell Biology, Department of Biomedicine, University of Bergen, Jonas Lies Vei 91, 5009 Bergen, Norway
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24
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Sannerud R, Marie M, Nizak C, Dale HA, Pernet-Gallay K, Perez F, Goud B, Saraste J. Rab1 defines a novel pathway connecting the pre-Golgi intermediate compartment with the cell periphery. Mol Biol Cell 2006; 17:1514-26. [PMID: 16421253 PMCID: PMC1415313 DOI: 10.1091/mbc.e05-08-0792] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The function of the pre-Golgi intermediate compartment (IC) and its relationship with the endoplasmic reticulum (ER) and Golgi remain only partially understood. Here, we report striking segregation of IC domains in polarized PC12 cells that develop neurite-like processes. Differentiation involves expansion of the IC and movement of Rab1-containing tubules to the growth cones of the neurites, whereas p58- and COPI-positive IC elements, like rough ER and Golgi, remain in the cell body. Exclusion of Rab1 effectors p115 and GM130 from the neurites further indicated that the centrifugal, Rab1-mediated pathway has functions that are not directly related to ER-to-Golgi trafficking. Disassembly of COPI coats did not affect this pathway but resulted in missorting of p58 to the neurites. Live cell imaging showed that green fluorescent protein (GFP)-Rab1A-containing IC elements move bidirectionally both within the neurites and cell bodies, interconnecting different ER exit sites and the cis-Golgi region. Moreover, in nonpolarized cells GFP-Rab1A-positive tubules moved centrifugally towards the cell cortex. Hydroxymethylglutaryl-CoA reductase, the key enzyme of cholesterol biosynthesis, colocalized with slowly sedimenting, Rab1-enriched membranes when the IC subdomains were separated by velocity sedimentation. These results reveal a novel pathway directly connecting the IC with the cell periphery and suggest that this Rab1-mediated pathway is linked to the dynamics of smooth ER.
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Affiliation(s)
- Ragna Sannerud
- Section of Anatomy and Cell Biology, Department of Biomedicine, University of Bergen, N-5009 Bergen, Norway
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25
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Abstract
In the secretory pathway, the forward (anterograde) membrane flow is compensated by retrograde transport of proteins and lipids. Membrane recycling is required for the maintenance of organelle homeostasis and the re-use of components of the transport machineries for the generation of new transport intermediates. However, the molecular mechanisms and other cellular functions of retrograde traffic are still poorly understood. In recent years, a multitude of protein factors that function in the secretory pathway have been discovered, most of them originally suggested to play a role in forward trafficking. However, in many cases subsequent studies have revealed that these proteins participate (also) in retrograde traffic. It is likely that this shift will continue, reflecting the fact that the two pathways are intimately connected.
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Affiliation(s)
- Ragna Sannerud
- Department of Anatomy and Cell Biology, University of Bergen, Jonas Lies vei 91, N-5009, Bergen, Norway
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26
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Ying M, Sannerud R, Flatmark T, Saraste J. Colocalization of Ca2+-ATPase and GRP94 with p58 and the effects of thapsigargin on protein recycling suggest the participation of the pre-Golgi intermediate compartment in intracellular Ca2+ storage. Eur J Cell Biol 2002; 81:469-83. [PMID: 12416724 DOI: 10.1078/0171-9335-00266] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We have studied the localization of functional components of cellular Ca2+ transport and storage and the effects of thapsigargin (TG), a specific inhibitor of the sarco-endoplasmic reticulum Ca2+-ATPase (SERCA), with respect to the p58-containing pre-Golgi intermediate compartment (IC). The depletion of Ca2+ stores in normal rat kidney (NRK) cells by TG abolished the retention of the KDEL-containing, Ca2+-binding, luminal ER chaperones GRP94/endoplasmin and GRP78/BiP, and resulted in the appearance of the proteins in the culture medium before inducing their synthesis. Immunolocalization of GRP94 in TG-treated cells showed that the protein was transported to the Golgi complex and, in parallel, the KDEL receptor was redistributed from the Golgi to p58-positive IC structures, but was not transported further to the ER. Similarly, p58 that normally cycles between the ER, IC, and cis-Golgi, was largely depleted from the cell periphery and arrested in large-sized IC elements and numerous vesicles or buds in the Golgi region, showing that TG selectively blocks its recycling from the IC back to the ER. Importantly, cell fractionation analyses and confocal fluorescence microscopy provided evidence that the IC elements in unperturbed cells contain SERCA and a considerable pool of GRP94. Thus, the observed effects of TG on protein retention and recycling can be explained by a change in the luminal Ca2+ concentration of the IC. Moreover, the compositional properties of the IC elements suggest that they participate in intracellular Ca2+ storage.
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Affiliation(s)
- Ming Ying
- Department of Biochemistry and Molecular Biology, University of Bergen, Norway
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