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Presenilin 1 Modulates Acetylcholinesterase Trafficking and Maturation. Int J Mol Sci 2023; 24:ijms24021437. [PMID: 36674948 PMCID: PMC9864477 DOI: 10.3390/ijms24021437] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 01/08/2023] [Accepted: 01/09/2023] [Indexed: 01/15/2023] Open
Abstract
In Alzheimer's disease (AD), the reduction in acetylcholinesterase (AChE) enzymatic activity is not paralleled with changes in its protein levels, suggesting the presence of a considerable enzymatically inactive pool in the brain. In the present study, we validated previous findings, and, since inactive forms could result from post-translational modifications, we analyzed the glycosylation of AChE by lectin binding in brain samples from sporadic and familial AD (sAD and fAD). Most of the enzymatically active AChE was bound to lectins Canavalia ensiformis (Con A) and Lens culinaris agglutinin (LCA) that recognize terminal mannoses, whereas Western blot assays showed a very low percentage of AChE protein being recognized by the lectin. This indicates that active and inactive forms of AChE vary in their glycosylation pattern, particularly in the presence of terminal mannoses in active ones. Moreover, sAD subjects showed reduced binding to terminal mannoses compared to non-demented controls, while, for fAD patients that carry mutations in the PSEN1 gene, the binding was higher. The role of presenilin-1 (PS1) in modulating AChE glycosylation was then studied in a cellular model that overexpresses PS1 (CHO-PS1). In CHO-PS1 cells, binding to LCA indicates that AChE displays more terminal mannoses in oligosaccharides with a fucosylated core. Immunocytochemical assays also demonstrated increased presence of AChE in the trans-Golgi. Moreover, AChE enzymatic activity was higher in plasmatic membrane of CHO-PS1 cells. Thus, our results indicate that PS1 modulates trafficking and maturation of AChE in Golgi regions favoring the presence of active forms in the membrane.
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2
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Suga K, Yamamoto-Hijikata S, Terao Y, Akagawa K, Ushimaru M. Golgi stress induces upregulation of the ER-Golgi SNARE Syntaxin-5, altered βAPP processing, and Caspase-3-dependent apoptosis in NG108-15 cells. Mol Cell Neurosci 2022; 121:103754. [PMID: 35842170 DOI: 10.1016/j.mcn.2022.103754] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 05/29/2022] [Accepted: 07/07/2022] [Indexed: 01/06/2023] Open
Abstract
The involvement of secretory pathways and Golgi dysfunction in neuronal cells during Alzheimer's disease progression is poorly understood. Our previous overexpression and knockdown studies revealed that the intracellular protein level of Syntaxin-5, an endoplasmic reticulum-Golgi soluble N-ethylmaleimide-sensitive factor-attachment protein receptor (SNARE), modulates beta-amyloid precursor protein processing in neuronal cells. We recently showed that changes in endogenous Syntaxin-5 protein expression occur under stress induction. Syntaxin-5 was upregulated by endoplasmic reticulum stress but was degraded by Caspase-3 during apoptosis in neuronal cells. In addition, we showed that sustained endoplasmic reticulum stress promotes Caspase-3-dependent apoptosis during the later phase of the endoplasmic reticulum stress response in NG108-15 cells. In this study, to elucidate the consequences of secretory pathway dysfunction in beta-amyloid precursor protein processing that lead to neuronal cell death, we examined the effect of various stresses on endoplasmic reticulum-Golgi SNARE expression and beta-amyloid precursor protein processing. By using compounds to disrupt Golgi function, we show that Golgi stress promotes upregulation of the endoplasmic reticulum-Golgi SNARE Syntaxin-5, and prolonged stress causes Caspase-3-dependent apoptosis. Golgi stress induced intracellular beta-amyloid precursor protein accumulation and a concomitant decrease in total amyloid-beta production. We also examined the protective effect of the chemical chaperone 4-phenylbutylate on changes in amyloid-beta production and the activation of Caspase-3 induced by endoplasmic reticulum and Golgi stress. The compound alleviated the increase in the amyloid-beta 1-42/amyloid-beta 1-40 ratio induced by endoplasmic reticulum and Golgi stress. Furthermore, 4-phenylbutylate could rescue Caspase-3-dependent apoptosis induced by prolonged organelle stress. These results suggest that organelle stress originating from the endoplasmic reticulum and Golgi has a substantial impact on the amyloidogenic processing of beta-amyloid precursor protein and Caspase-3-dependent apoptosis, leading to neuronal cell death.
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Affiliation(s)
- Kei Suga
- Department of Chemistry, Kyorin University, Faculty of Medicine, Mitaka, Tokyo 181-8611, Japan; Department of Medical Physiology, Kyorin University, Faculty of Medicine, Mitaka, Tokyo 181-8611, Japan.
| | | | - Yasuo Terao
- Department of Medical Physiology, Kyorin University, Faculty of Medicine, Mitaka, Tokyo 181-8611, Japan
| | - Kimio Akagawa
- Department of Medical Physiology, Kyorin University, Faculty of Medicine, Mitaka, Tokyo 181-8611, Japan
| | - Makoto Ushimaru
- Department of Chemistry, Kyorin University, Faculty of Medicine, Mitaka, Tokyo 181-8611, Japan
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3
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Deaton CA, Johnson GVW. Presenilin 1 Regulates Membrane Homeostatic Pathways that are Dysregulated in Alzheimer's Disease. J Alzheimers Dis 2021; 77:961-977. [PMID: 32804090 DOI: 10.3233/jad-200598] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mutations in the PSEN1 gene, encoding presenilin 1 (PS1), are the most common cause of familial Alzheimer's disease (fAD). Since the first mutations in the PSEN1 gene were discovered more than 25 years ago, many postulated functions of PS1 have been investigated. The majority of earlier studies focused on its role as the catalytic component of the γ-secretase complex, which in concert with β site amyloid precursor protein cleaving enzyme 1 (BACE1), mediates the formation of Aβ from amyloid-β protein precursor (AβPP). Though mutant PS1 was originally considered to cause AD by promoting Aβ pathology through its protease function, it is now becoming clear that PS1 is a multifunctional protein involved in regulating membrane dynamics and protein trafficking. Therefore, through loss of these abilities, mutant PS1 has the potential to impair numerous cellular functions such as calcium flux, organization of proteins in different compartments, and protein turnover via vacuolar metabolism. Impaired calcium signaling, vacuolar dysfunction, mitochondrial dysfunction, and increased ER stress, among other related membrane-dependent disturbances, have been considered critical to the development and progression of AD. Given that PS1 plays a key regulatory role in all these processes, this review will describe the role of PS1 in different cellular compartments and provide an integrated view of how PS1 dysregulation (due to mutations or other causes) could result in impairment of various cellular processes and result in a "multi-hit", integrated pathological outcome that could contribute to the etiology of AD.
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Affiliation(s)
- Carol A Deaton
- Cell Biology of Disease Program and the Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Gail V W Johnson
- Cell Biology of Disease Program and the Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY, USA
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4
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Fourriere L, Gleeson PA. Amyloid β production along the neuronal secretory pathway: Dangerous liaisons in the Golgi? Traffic 2021; 22:319-327. [PMID: 34189821 DOI: 10.1111/tra.12808] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 05/24/2021] [Accepted: 06/27/2021] [Indexed: 12/11/2022]
Abstract
β-amyloid peptides (Aβ) are generated in intracellular compartments of neurons and secreted to form cytotoxic fibrils and plaques. Dysfunctional membrane trafficking contributes to aberrant Aβ production and Alzheimer's disease. Endosomes represent one of the major sites for Aβ production and recently the Golgi has re-emerged also as a major location for amyloid precursor protein (APP) processing and Aβ production. Based on recent findings, here we propose that APP processing in the Golgi is finely tuned by segregating newly-synthesised APP and the β-secretase BACE1 within the Golgi and into distinct trans-Golgi network transport pathways. We hypothesise that there are multiple mechanisms responsible for segregating APP and BACE1 during transit through the Golgi, and that perturbation in Golgi morphology associated with Alzheimer's disease, and or changes in cholesterol metabolism associated with Alzheimer's disease risk factors, may lead to a loss of partitioning and enhanced Aβ production.
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Affiliation(s)
- Lou Fourriere
- The Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Paul A Gleeson
- The Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
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5
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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] [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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6
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Tan JZA, Fourriere L, Wang J, Perez F, Boncompain G, Gleeson PA. Distinct anterograde trafficking pathways of BACE1 and amyloid precursor protein from the TGN and the regulation of amyloid-β production. Mol Biol Cell 2020; 31:27-44. [PMID: 31746668 PMCID: PMC6938271 DOI: 10.1091/mbc.e19-09-0487] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 11/01/2019] [Accepted: 11/15/2019] [Indexed: 01/08/2023] Open
Abstract
Processing of amyloid precursor protein (APP) by the β-secretase BACE1 is the initial step of the amyloidogenic pathway to generate amyloid-β (Aβ). Although newly synthesized BACE1 and APP are transported along the secretory pathway, it is not known whether BACE1 and APP share the same post-Golgi trafficking pathways or are partitioned into different transport routes. Here we demonstrate that BACE1 exits the Golgi in HeLa cells and primary neurons by a pathway distinct from the trafficking pathway for APP. By using the Retention Using Selective Hooks system, we show that BACE1 is transported from the trans-Golgi network to the plasma membrane in an AP-1- and Arf1/4-dependent manner. Subsequently, BACE1 is endocytosed to early and recycling endosomes. Perturbation of BACE1 post-Golgi trafficking results in an increase in BACE1 cleavage of APP and increased production of both Aβ40 and Aβ42. These findings reveal that Golgi exit of BACE1 and APP in primary neurons is tightly regulated, resulting in their segregation along different transport routes, which limits APP processing.
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Affiliation(s)
- Jing Zhi A. Tan
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia
| | - Lou Fourriere
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia
| | - Jingqi Wang
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia
| | - Franck Perez
- Dynamics of Intracellular Organization Laboratory, Institut Curie, PSL Research University, Sorbonne Université, Centre National de la Recherche Scientifique, UMR 144, 75248 Paris, France
| | - Gaelle Boncompain
- Dynamics of Intracellular Organization Laboratory, Institut Curie, PSL Research University, Sorbonne Université, Centre National de la Recherche Scientifique, UMR 144, 75248 Paris, France
| | - Paul A. Gleeson
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia
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7
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The role of membrane trafficking in the processing of amyloid precursor protein and production of amyloid peptides in Alzheimer's disease. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:697-712. [PMID: 30639513 DOI: 10.1016/j.bbamem.2018.11.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 11/25/2018] [Accepted: 11/29/2018] [Indexed: 01/18/2023]
Abstract
Alzheimer's disease (AD) is characterized by progressive accumulation of misfolded proteins, which form senile plaques and neurofibrillary tangles, and the release of inflammatory mediators by innate immune responses. β-Amyloid peptide (Aβ) is derived from sequential processing of the amyloid precursor protein (APP) by membrane-bound proteases, namely the β-secretase, BACE1, and γ-secretase. Membrane trafficking plays a key role in the regulation of APP processing as both APP and the processing secretases traffic along distinct pathways. Genome wide sequencing studies have identified several AD susceptibility genes which regulate membrane trafficking events. To understand the pathogenesis of AD it is critical that the cell biology of APP and Aβ production in neurons is well defined. This review discusses recent advances in unravelling the membrane trafficking events associated with the production of Aβ, and how AD susceptible alleles may perturb the sorting and transport of APP and BACE1. Mechanisms whereby inflammation may influence APP processing are also considered.
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8
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Khan I, Krishnaswamy S, Sabale M, Groth D, Wijaya L, Morici M, Berger I, Schaffitzel C, Fraser PE, Martins RN, Verdile G. Efficient production of a mature and functional gamma secretase protease. Sci Rep 2018; 8:12834. [PMID: 30150752 PMCID: PMC6110731 DOI: 10.1038/s41598-018-30788-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 08/06/2018] [Indexed: 12/27/2022] Open
Abstract
Baculoviral protein expression in insect cells has been previously used to generate large quantities of a protein of interest for subsequent use in biochemical and structural analyses. The MultiBac baculovirus protein expression system has enabled, the use of a single baculovirus to reconstitute a protein complex of interest, resulting in a larger protein yield. Using this system, we aimed to reconstruct the gamma (γ)-secretase complex, a multiprotein enzyme complex essential for the production of amyloid-β (Aβ) protein. A MultiBac vector containing all components of the γ-secretase complex was generated and expression was observed for all components. The complex was active in processing APP and Notch derived γ-secretase substrates and proteolysis could be inhibited with γ-secretase inhibitors, confirming specificity of the recombinant γ-secretase enzyme. Finally, affinity purification was used to purify an active recombinant γ-secretase complex. In this study we demonstrated that the MultiBac protein expression system can be used to generate an active γ-secretase complex and provides a new tool to study γ-secretase enzyme and its variants.
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Affiliation(s)
- Imran Khan
- School of Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia. .,School of Psychiatry and Clinical Neurosciences, University of Western Australia, Crawley, Western Australia, Australia. .,Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
| | - Sudarsan Krishnaswamy
- Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
| | - Miheer Sabale
- School of Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
| | - David Groth
- School of Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
| | - Linda Wijaya
- Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.,School of Psychology and Exercise Sciences, Murdoch University, Murdoch, Western Australia, Australia
| | - Michael Morici
- School of Psychiatry and Clinical Neurosciences, University of Western Australia, Crawley, Western Australia, Australia.,Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
| | - Imre Berger
- European Molecular Biology Laboratories, Grenoble, France.,School of Biochemistry, University of Bristol, Bristol, UK
| | - Christiane Schaffitzel
- European Molecular Biology Laboratories, Grenoble, France.,School of Biochemistry, University of Bristol, Bristol, UK
| | - Paul E Fraser
- Tanz Centre for Research in Neurodegenerative Diseases and Department of Medical Biophysics, Krembil Discovery Tower, University of Toronto, Toronto, Ontario, Canada
| | - Ralph N Martins
- School of Psychiatry and Clinical Neurosciences, University of Western Australia, Crawley, Western Australia, Australia.,Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.,Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Giuseppe Verdile
- School of Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia. .,School of Psychiatry and Clinical Neurosciences, University of Western Australia, Crawley, Western Australia, Australia. .,Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
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9
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Kanatsu K, Tomita T. Membrane trafficking and proteolytic activity of γ-secretase in Alzheimer’s disease. Biol Chem 2016; 397:827-35. [DOI: 10.1515/hsz-2016-0146] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 07/04/2016] [Indexed: 12/26/2022]
Abstract
Abstract
γ-Secretase is an intramembrane-cleaving protease that generates various forms of amyloid-β peptides (Aβ) that accumulate in the brains of Alzheimer’s disease (AD) patients. The intracellular trafficking and subcellular localization of γ-secretase are linked to both qualitative and quantitative changes in Aβ production. However, the precise intracellular localization of γ-secretase as well as its detailed regulatory mechanisms have remained elusive. Recent genetic studies on AD provide ample evidence that alteration of the subcellular localization of γ-secretase contributes to the pathogenesis of AD. Here we review our current understanding of the intracellular membrane trafficking of γ-secretase, the association between its localization and proteolytic activity, and the possibility of γ-secretase as a therapeutic target against AD.
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10
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Carroll CM, Li YM. Physiological and pathological roles of the γ-secretase complex. Brain Res Bull 2016; 126:199-206. [PMID: 27133790 DOI: 10.1016/j.brainresbull.2016.04.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 04/19/2016] [Accepted: 04/27/2016] [Indexed: 12/27/2022]
Abstract
Gamma-secretase (GS) is an enzyme complex that cleaves numerous substrates, and it is best known for cleaving amyloid precursor protein (APP) to form amyloid-beta (Aβ) peptides. Aberrant cleavage of APP can lead to Alzheimer's disease, so much research has been done to better understand GS structure and function in hopes of developing therapeutics for Alzheimer's. Therefore, most of the attention in this field has been focused on developing modulators that reduce pathogenic forms of Aβ while leaving Notch and other GS substrates intact, but GS provides multiple avenues of modulation that could improve AD pathology. GS has complex regulation, through its essential subunits and other associated proteins, providing other targets for AD drugs. Therapeutics can also alter GS trafficking and thereby improve cognition, or move beyond Aβ entirely, effecting Notch and neural stem cells. GS also cleaves substrates that affect synaptic morphology and function, presenting another window by which GS modulation could improve AD pathology. Taken together, GS presents a unique cross road for neural processes and an ideal target for AD therapeutics.
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Affiliation(s)
- Courtney M Carroll
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, NY, United States; Program of Neuroscience, Weill Graduate School of Medical Sciences of Cornell University, NY, United States.
| | - Yue-Ming Li
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, NY, United States; Program of Neuroscience, Weill Graduate School of Medical Sciences of Cornell University, NY, United States; Program of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University, NY, United States
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11
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Suga K, Saito A, Akagawa K. ER stress response in NG108-15 cells involves upregulation of syntaxin 5 expression and reduced amyloid β peptide secretion. Exp Cell Res 2015; 332:11-23. [DOI: 10.1016/j.yexcr.2015.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 01/05/2015] [Accepted: 01/07/2015] [Indexed: 01/24/2023]
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12
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Chen WT, Hsieh YF, Huang YJ, Lin CC, Lin YT, Liu YC, Lien CC, Cheng IHJ. G206D Mutation of Presenilin-1 Reduces Pen2 Interaction, Increases Aβ42/Aβ40 Ratio and Elevates ER Ca(2+) Accumulation. Mol Neurobiol 2014; 52:1835-1849. [PMID: 25394380 DOI: 10.1007/s12035-014-8969-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 10/28/2014] [Indexed: 12/23/2022]
Abstract
Early-onset familial Alzheimer's disease (AD) is most commonly associated with the mutations in presenilin-1 (PS1). PS1 is the catalytic component of the γ-secretase complex, which cleaves amyloid precursor protein to produce amyloid-β (Aβ), the major cause of AD. Presenilin enhancer 2 (Pen2) is critical for activating γ-secretase and exporting PS1 from endoplasmic reticulum (ER). Among all the familial AD-linked PS1 mutations, mutations at the G206 amino acid are the most adjacent position to the Pen2 binding site. Here, we characterized the effect of a familial AD-linked PS1 G206D mutation on the PS1-Pen2 interaction and the accompanied alteration in γ-secretase-dependent and -independent functions. We found that the G206D mutation reduced PS1-Pen2 interaction, but did not abolish γ-secretase formation and PS1 endoproteolysis. For γ-secretase-dependent function, the G206D mutation increased Aβ42 production but not Notch cleavage. For γ-secretase-independent function, this mutation disrupted the ER calcium homeostasis but not lysosomal calcium homeostasis and autophagosome maturation. Impaired ER calcium homeostasis may due to the reduced mutant PS1 level in the ER. Although this mutation did not alter the cell survival under stress, both increased Aβ42 ratio and disturbed ER calcium regulation could be the mechanisms underlying the pathogenesis of the familial AD-linked PS1 G206D mutation.
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Affiliation(s)
- Wei-Ting Chen
- Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan.,Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.,Institute of Biochemistry and Molecular Biology, School of Life Science, National Yang-Ming University, Taipei, Taiwan
| | - Yi-Fang Hsieh
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Yan-Jing Huang
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Che-Ching Lin
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Yen-Tung Lin
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Yu-Chao Liu
- Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan
| | - Cheng-Chang Lien
- Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan.,Brain Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Irene Han-Juo Cheng
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan. .,Brain Research Center, National Yang-Ming University, Taipei, Taiwan. .,Infection and Immunity Research Center, National Yang-Ming University, Taipei, Taiwan. .,Immunology Center, Taipei Veterans General Hospital, Taipei, Taiwan. .,Institute of Brain Science, School of Medicine, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Taipei, 112, Taiwan.
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13
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Smolarkiewicz M, Skrzypczak T, Michalak M, Leśniewicz K, Walker JR, Ingram G, Wojtaszek P. Gamma-secretase subunits associate in intracellular membrane compartments in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3015-27. [PMID: 24723404 PMCID: PMC4071823 DOI: 10.1093/jxb/eru147] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Gamma-secretase is a multisubunit complex with intramembrane proteolytic activity. In humans it was identified in genetic screens of patients suffering from familial forms of Alzheimer's disease, and since then it was shown to mediate cleavage of more than 80 substrates, including amyloid precursor protein or Notch receptor. Moreover, in animals, γ-secretase was shown to be involved in regulation of a wide range of cellular events, including cell signalling, regulation of endocytosis of membrane proteins, their trafficking, and degradation. Here we show that genes coding for γ-secretase homologues are present in plant genomes. Also, amino acid motifs crucial for γ-secretase activity are conserved in plants. Moreover, all γ-secretase subunits: PS1/PS2, APH-1, PEN-2, and NCT colocalize and interact with each other in Arabidopsis thaliana protoplasts. The intracellular localization of γ-secretase subunits in Arabidopsis protoplasts revealed a distribution in endomembrane system compartments that is consistent with data from animal studies. Together, our data may be considered as a starting point for analysis of γ-secretase in plants.
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Affiliation(s)
- Michalina Smolarkiewicz
- Department of Molecular and Cellular Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Tomasz Skrzypczak
- Department of Molecular and Cellular Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Michał Michalak
- Department of Molecular and Cellular Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Krzysztof Leśniewicz
- Department of Molecular and Cellular Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - J Ross Walker
- Institute of Molecular Plant Sciences, University of Edinburgh, King's Buildings, Mayfield Rd, Edinburgh EH9 3JH, UK
| | - Gwyneth Ingram
- Institute of Molecular Plant Sciences, University of Edinburgh, King's Buildings, Mayfield Rd, Edinburgh EH9 3JH, UK UMR 5667 CNRS-INRA-ENSL-UCB Lyon I, Reproduction et Développement des Plantes, ENS Lyon, 46, Allée d'Italie, 69364 LYON Cedex 07, France
| | - Przemysław Wojtaszek
- Department of Molecular and Cellular Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
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Early onset Alzheimer's disease and oxidative stress. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2014; 2014:375968. [PMID: 24669286 PMCID: PMC3942075 DOI: 10.1155/2014/375968] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 11/18/2013] [Indexed: 01/30/2023]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia in elderly adults. It is estimated that 10% of the world's population aged more than 60-65 years could currently be affected by AD, and that in the next 20 years, there could be more than 30 million people affected by this pathology. One of the great challenges in this regard is that AD is not just a scientific problem; it is associated with major psychosocial and ethical dilemmas and has a negative impact on national economies. The neurodegenerative process that occurs in AD involves a specific nervous cell dysfunction, which leads to neuronal death. Mutations in APP, PS1, and PS2 genes are causes for early onset AD. Several animal models have demonstrated that alterations in these proteins are able to induce oxidative damage, which in turn favors the development of AD. This paper provides a review of many, although not all, of the mutations present in patients with familial Alzheimer's disease and the association between some of these mutations with both oxidative damage and the development of the pathology.
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Zhang X, Song W. The role of APP and BACE1 trafficking in APP processing and amyloid-β generation. ALZHEIMERS RESEARCH & THERAPY 2013; 5:46. [PMID: 24103387 PMCID: PMC3978418 DOI: 10.1186/alzrt211] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Neuritic plaques in the brain are a major neuropathological hallmark of Alzheimer’s disease. They are formed by the deposition and aggregation of extracellular amyloid-β protein (Aβ). Aβ is derived from the sequential cleavage of amyloid-β precursor protein (APP) by β-secretase and γ-secretase. β-Site APP cleaving enzyme 1 (BACE1) functions as the primary, if not sole, β-secretase in vivo and is essential for Aβ production. Regulation of APP processing is a major focus of research into AD pathogenesis. The trafficking systems of APP and its cleavage enzymes are complex. Transporting APP and secretases into the same subcellular organelles facilitates their interaction and favors APP processing. The role of APP and BACE1 trafficking in the amyloidgenic pathway and the underlying mechanisms for Aβ production are discussed in this review. In addition, the distinct mechanisms of amino- and carboxy-terminal Aβ generation are reviewed.
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Affiliation(s)
- Xiaojie Zhang
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, Graduate Program in Neuroscience, The University of British Columbia, 2255 Wesbrook Mall, Vancouver BC V6T 1Z3, Canada
| | - Weihong Song
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, Graduate Program in Neuroscience, The University of British Columbia, 2255 Wesbrook Mall, Vancouver BC V6T 1Z3, Canada
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Smolarkiewicz M, Skrzypczak T, Wojtaszek P. The very many faces of presenilins and the γ-secretase complex. PROTOPLASMA 2013; 250:997-1011. [PMID: 23504135 PMCID: PMC3788181 DOI: 10.1007/s00709-013-0494-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 03/01/2013] [Indexed: 05/02/2023]
Abstract
Presenilin is a central, catalytic component of the γ-secretase complex which conducts intramembrane cleavage of various protein substrates. Although identified and mainly studied through its role in the development of amyloid plaques in Alzheimer disease, γ-secretase has many other important functions. The complex seems to be evolutionary conserved throughout the Metazoa, but recent findings in plants and Dictyostelium discoideum as well as in archeons suggest that its evolution and functions might be much more diversified than previously expected. In this review, a selective survey of the multitude of functions of presenilins and the γ-secretase complex is presented. Following a brief overview of γ-secretase structure, assembly and maturation, three functional aspects are analyzed: (1) the role of γ-secretase in autophagy and phagocytosis; (2) involvement of the complex in signaling related to endocytosis; and (3) control of calcium fluxes by presenilins.
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Affiliation(s)
- Michalina Smolarkiewicz
- Department of Molecular and Cellular Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Tomasz Skrzypczak
- Department of Molecular and Cellular Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Przemysław Wojtaszek
- Department of Molecular and Cellular Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
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Martiskainen H, Haapasalo A, Kurkinen KMA, Pihlajamäki J, Soininen H, Hiltunen M. Targeting ApoE4/ApoE receptor LRP1 in Alzheimer's disease. Expert Opin Ther Targets 2013; 17:781-94. [PMID: 23573918 DOI: 10.1517/14728222.2013.789862] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
INTRODUCTION Progressive neuronal loss is a key feature in Alzheimer's disease (AD), which is the most common neurodegenerative disorder in the aging population. Currently, there are no therapeutic means to intervene neuronal damage in AD and therefore innovative approaches to discover novel strategies for the treatment of AD are needed. Based on the prevailing amyloid cascade hypothesis, it is conceivable that lowering the β-amyloid (Aβ) levels is sufficient to slow down the disease process, if started early enough. AREAS COVERED Here, we review genetic and biological functions related to apolipoprotein E (ApoE) and low-density lipoprotein receptor-related protein 1 receptor (LRP1)-mediated clearance of Aβ. Furthermore, we discuss the AD-related therapeutic potential of targeting to ApoE receptor LRP1 at the blood-brain barrier (BBB) and in the periphery. EXPERT OPINION Due to the recent setbacks in the clinical trials targeting AD, it is instrumental to seek alternative therapeutic approaches, which aim to reduce the accumulation of Aβ in the brain tissue. As the ApoE/LRP1-mediated clearance of Aβ across the BBB is the key event in the regulation of Aβ transcytosis from brain to periphery, direct targeting of this protein entity at the BBB holds a great potential in the treatment of AD.
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Affiliation(s)
- Henna Martiskainen
- Kuopio University Hospital, Institute of Clinical Medicine-Neurology, University of Eastern Finland and Department of Neurology, Kuopio, Finland
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De Gasperi R, Gama Sosa MA, Elder GA. Presenilin-1 regulates the constitutive turnover of the fibronectin matrix in endothelial cells. BMC BIOCHEMISTRY 2012; 13:28. [PMID: 23259730 PMCID: PMC3556133 DOI: 10.1186/1471-2091-13-28] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2012] [Accepted: 12/13/2012] [Indexed: 12/29/2022]
Abstract
BACKGROUND Presenilin-1 (PS1) is a transmembrane protein first discovered because of its association with familial Alzheimer's disease. Mice with null mutations in PS1 die shortly after birth exhibiting multiple CNS and non-CNS abnormalities. One of the most prominent features in the brains of PS1-/- embryos is a vascular dysgenesis that leads to multiple intracerebral hemorrhages. The molecular and cellular basis for the vascular dysgenesis in PS1-/- mice remains incompletely understood. Because the extracellular matrix plays key roles in vascular development we hypothesized that an abnormal extracellular matrix might be present in endothelial cells lacking PS1 and examined whether the lack of PS1 affects expression of fibronectin a component of the extracellular matrix known to be essential for vascular development. RESULTS We report that primary as well as continuously passaged PS1-/- endothelial cells contain more fibronectin than wild type cells and that the excess fibronectin in PS1-/- endothelial cells is incorporated into a fibrillar network. Supporting the in vivo relevance of this observation fibronectin expression was increased in microvascular preparations isolated from E14.5 to E18.5 PS1-/- embryonic brain. Reintroduction of PS1 into PS1-/- endothelial cells led to a progressive decrease in fibronectin levels showing that the increased fibronectin in PS1-/- endothelial cells was due to loss of PS1. Increases in fibronectin protein in PS1-/- endothelial cells could not be explained by increased levels of fibronectin RNA nor based on metabolic labeling studies by increased protein synthesis. Rather we show based on the rate of turnover of exogenously added biotinylated fibronectin that increased fibronectin in PS1-/- endothelial cells results from a slower degradation of the fibronectin fibrillar matrix on the cell surface. CONCLUSIONS These studies show that PS1 regulates the constitutive turnover of the fibronectin matrix in endothelial cells. These studies provide molecular clues that may help to explain the origin of the vascular dysgenesis that develops in PS1-/- embryonic mice.
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Affiliation(s)
- Rita De Gasperi
- Research and Development, James J. Peters Department of Veterans Affairs Medical Center, Bronx, NY, 10468, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Miguel A Gama Sosa
- Research and Development, James J. Peters Department of Veterans Affairs Medical Center, Bronx, NY, 10468, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Gregory A Elder
- Neurology Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, NY, 10468, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
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Haass C, Kaether C, Thinakaran G, Sisodia S. Trafficking and proteolytic processing of APP. Cold Spring Harb Perspect Med 2012; 2:a006270. [PMID: 22553493 PMCID: PMC3331683 DOI: 10.1101/cshperspect.a006270] [Citation(s) in RCA: 723] [Impact Index Per Article: 60.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Accumulations of insoluble deposits of amyloid β-peptide are major pathological hallmarks of Alzheimer disease. Amyloid β-peptide is derived by sequential proteolytic processing from a large type I trans-membrane protein, the β-amyloid precursor protein. The proteolytic enzymes involved in its processing are named secretases. β- and γ-secretase liberate by sequential cleavage the neurotoxic amyloid β-peptide, whereas α-secretase prevents its generation by cleaving within the middle of the amyloid domain. In this chapter we describe the cell biological and biochemical characteristics of the three secretase activities involved in the proteolytic processing of the precursor protein. In addition we outline how the precursor protein maturates and traffics through the secretory pathway to reach the subcellular locations where the individual secretases are preferentially active. Furthermore, we illuminate how neuronal activity and mutations which cause familial Alzheimer disease affect amyloid β-peptide generation and therefore disease onset and progression.
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Affiliation(s)
- Christian Haass
- DZNE-German Center for Neurodegenerative Diseases, 80336 Munich, Germany; Adolf Butenandt-Institute, Biochemistry, Ludwig-Maximilians University, 80336 Munich, Germany.
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Rajendran L, Annaert W. Membrane Trafficking Pathways in Alzheimer's Disease. Traffic 2012; 13:759-70. [DOI: 10.1111/j.1600-0854.2012.01332.x] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 01/20/2012] [Accepted: 01/23/2012] [Indexed: 11/28/2022]
Affiliation(s)
- Lawrence Rajendran
- Systems and Cell Biology of Neurodegeneration; Division of Psychiatry Research; University of Zurich; August-Forel Str. 1; Zurich; 8008; Switzerland
| | - Wim Annaert
- Laboratory for Membrane Trafficking; Center for Human Genetics (KULeuven) & VIB-Center for the Biology of Disease; Gasthuisberg O&N4, Herestraat 49; Leuven; B-3000; Belgium
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Abstract
AD (Alzheimer's disease) is a neurodegenerative disease characterized by a gradual loss of neurons and the accumulation of neurotoxic Aβ (amyloid β-peptide) and hyperphosphorylated tau. The discovery of mutations in three genes, PSEN1 (presenilin 1), PSEN2 (presenilin 2) and APP (amyloid precursor protein), in patients with FAD (familial AD) has made an important contribution towards an understanding of the disease aetiology; however, a complete molecular mechanism is still lacking. Both presenilins belong to the γ-secretase complex, and serve as the catalytic entity needed for the final cleavage of APP into Aβ. PSEN only functions within the γ-secretase complex through intra- and inter-molecular interactions with three other membrane components, including nicastrin, Aph-1 (anterior pharynx defective-1) and Pen-2 (PSEN enhancer-2). However, although the list of γ-secretase substrates is still expanding, other non-catalytic activities of presenilins are also increasing the complexity behind its molecular contribution towards AD. These γ-secretase-independent roles are so far mainly attributed to PSEN1, including the transport of membrane proteins, cell adhesion, ER (endoplasmic reticulum) Ca(2+) regulation and cell signalling. In the present minireview, we discuss the current understanding of the γ-secretase-independent roles of PSENs and their possible implications in respect of AD.
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22
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De Strooper B, Annaert W. Novel Research Horizons for Presenilins and γ-Secretases in Cell Biology and Disease. Annu Rev Cell Dev Biol 2010; 26:235-60. [DOI: 10.1146/annurev-cellbio-100109-104117] [Citation(s) in RCA: 199] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Bart De Strooper
- Center for Human Genetics, Katholieke Universiteit Leuven, and Department for Molecular and Developmental Genetics, VIB, Leuven, Belgium; ,
| | - Wim Annaert
- Center for Human Genetics, Katholieke Universiteit Leuven, and Department for Molecular and Developmental Genetics, VIB, Leuven, Belgium; ,
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23
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Inoue E, Deguchi-Tawarada M, Togawa A, Matsui C, Arita K, Katahira-Tayama S, Sato T, Yamauchi E, Oda Y, Takai Y. Synaptic activity prompts gamma-secretase-mediated cleavage of EphA4 and dendritic spine formation. ACTA ACUST UNITED AC 2009; 185:551-64. [PMID: 19414612 PMCID: PMC2700400 DOI: 10.1083/jcb.200809151] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Alzheimer's disease is an age-dependent neurodegenerative disorder that is characterized by a progressive decline in cognitive function. gamma-secretase dysfunction is evident in many cases of early onset familial Alzheimer's disease. However, the mechanism by which gamma-secretase dysfunction results in memory loss and neurodegeneration is not fully understood. Here, we demonstrate that gamma-secretase is localized at synapses and regulates spine formation. We identify EphA4, one of the Ephrin receptor family members, as a substrate of gamma-secretase, and find that EphA4 processing is enhanced by synaptic activity. Moreover, overexpression of EphA4 intracellular domain increases the number of dendritic spines by activating the Rac signaling pathway. These findings reveal a function for EphA4-mediated intracellular signaling in the morphogenesis of dendritic spines and suggest that the processing of EphA4 by gamma-secretase affects the pathogenesis of Alzheimer's disease.
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24
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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] [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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Marzolo MP, Bu G. Lipoprotein receptors and cholesterol in APP trafficking and proteolytic processing, implications for Alzheimer's disease. Semin Cell Dev Biol 2008; 20:191-200. [PMID: 19041409 DOI: 10.1016/j.semcdb.2008.10.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Accepted: 10/13/2008] [Indexed: 12/30/2022]
Abstract
Amyloid-beta (Abeta) peptide accumulation in the brain is central to the pathogenesis of Alzheimer's disease (AD). Abeta is produced through proteolytic processing of a transmembrane protein, beta-amyloid precursor protein (APP), by beta- and gamma-secretases. Mounting evidence has demonstrated that alterations in APP cellular trafficking and localization directly impact its processing to Abeta. Members of the low-density lipoprotein receptor family, including LRP, LRP1B, SorLA/LR11, and apoER2, interact with APP and regulate its endocytic trafficking. Additionally, APP trafficking and processing are greatly affected by cellular cholesterol content. In this review, we summarize the current understanding of the roles of lipoprotein receptors and cholesterol in APP trafficking and processing and their implication for AD pathogenesis and therapy.
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Affiliation(s)
- Maria-Paz Marzolo
- FONDAP Center for Cell Regulation and Pathology (CRCP), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile and MIFAB, Santiago, Chile
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26
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Spasic D, Annaert W. Building gamma-secretase: the bits and pieces. J Cell Sci 2008; 121:413-20. [PMID: 18256384 DOI: 10.1242/jcs.015255] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
gamma-Secretase is a promiscuous aspartyl protease responsible for the final intramembrane cleavage of various type I transmembrane proteins after their large ectodomains are shed. The vast functional diversity of its substrates, which are involved in cell fate decisions, adhesion, neurite outgrowth and synapse formation, highlights the important role gamma-secretase plays in development and neurogenesis. The most renowned substrates are the amyloid precursor protein and Notch, from which gamma-secretase liberates amyloid beta peptides and induces downstream signalling, respectively. gamma-Secretase is a multiprotein complex containing presenilin (which harbours the catalytic site), nicastrin, APH1 and PEN2. Its assembly occurs under tight control of ER-Golgi recycling regulators, which allows defined quantities of complexes to reach post-Golgi compartments, where gamma-secretase activity is regulated by multiple other factors. 3D-EM rendering reveals a complex with a translucent inner space, suggesting the presence of a water-filled cavity required for intramembrane proteolysis. Despite huge efforts, we are now only beginning to unravel the assembly, stoichiometry, activation and subcellular location of gamma-secretase.
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Affiliation(s)
- Dragana Spasic
- Laboratory for Membrane Trafficking, Center for Human Genetics (KULeuven) and Department of Molecular and Developmental Genetics (VIB), O&N1, Gasthuisberg, Herestraat 49, Leuven, Belgium
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27
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Abstract
Gamma-Secretase is a promiscuous protease that cleaves bitopic membrane proteins within the lipid bilayer. Elucidating both the mechanistic basis of gamma-secretase proteolysis and the precise factors regulating substrate identification is important because modulation of this biochemical degradative process can have important consequences in a physiological and pathophysiological context. Here, we briefly review such information for all major classes of intramembranously cleaving proteases (I-CLiPs), with an emphasis on gamma-secretase, an I-CLiP closely linked to the etiology of Alzheimer's disease. A large body of emerging data allows us to survey the substrates of gamma-secretase to ascertain the conformational features that predispose a peptide to cleavage by this enigmatic protease. Because substrate specificity in vivo is closely linked to the relative subcellular compartmentalization of gamma-secretase and its substrates, we also survey the voluminous body of literature concerning the traffic of gamma-secretase and its most prominent substrate, the amyloid precursor protein.
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Affiliation(s)
- A. J. Beel
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine, Rm. 5142 MRBIII, 21st Ave. S., Nashville, Tennessee 37232-8725 USA
| | - C. R. Sanders
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine, Rm. 5142 MRBIII, 21st Ave. S., Nashville, Tennessee 37232-8725 USA
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Eskelinen EL. New insights into the mechanisms of macroautophagy in mammalian cells. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 266:207-47. [PMID: 18544495 DOI: 10.1016/s1937-6448(07)66005-5] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Macroautophagy is a self-digesting pathway responsible for the removal of long-lived proteins and organelles by the lysosomal compartment. Parts of the cytoplasm are first segregated in double-membrane-bound autophagosomes, which then undergo a multistep maturation process including fusion with endosomes and lysosomes. The segregated cytoplasm is then degraded by the lysosomal hydrolases. The discovery of ATG genes has greatly enhanced our understanding of the mechanisms of this pathway. Two novel ubiquitin-like protein conjugation systems were shown to function during autophagosome formation. Autophagy has been shown to play a role in a wide variety of physiological processes including energy metabolism, organelle turnover, growth regulation, and aging. Impaired autophagy can lead to diseases such as cardiomyopathy and cancer. This review summarizes current knowledge about the formation and maturation of autophagosomes, the role of macroautophagy in various physiological and pathological conditions, and the signaling pathways that regulate this process in mammalian cells.
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Affiliation(s)
- Eeva-Liisa Eskelinen
- Division of Biochemistry, Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
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29
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Rennolds J, Tower C, Musgrove L, Fan L, Maloney K, Clancy JP, Kirk KL, Sztul E, Cormet-Boyaka E. Cystic Fibrosis Transmembrane Conductance Regulator Trafficking Is Mediated by the COPI Coat in Epithelial Cells. J Biol Chem 2008; 283:833-9. [DOI: 10.1074/jbc.m706504200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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30
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Fuentealba RA, Barría MI, Lee J, Cam J, Araya C, Escudero CA, Inestrosa NC, Bronfman FC, Bu G, Marzolo MP. ApoER2 expression increases Abeta production while decreasing Amyloid Precursor Protein (APP) endocytosis: Possible role in the partitioning of APP into lipid rafts and in the regulation of gamma-secretase activity. Mol Neurodegener 2007; 2:14. [PMID: 17620134 PMCID: PMC1939850 DOI: 10.1186/1750-1326-2-14] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2007] [Accepted: 07/09/2007] [Indexed: 11/10/2022] Open
Abstract
Background The generation of the amyloid-β peptide (Aβ) through the proteolytic processing of the amyloid precursor protein (APP) is a central event in the pathogenesis of Alzheimer's disease (AD). Recent studies highlight APP endocytosis and localization to lipid rafts as important events favoring amyloidogenic processing. However, the precise mechanisms underlying these events are poorly understood. ApoER2 is a member of the low density lipoprotein receptor (LDL-R) family exhibiting slow endocytosis rate and a significant association with lipid rafts. Despite the important neurophysiological roles described for ApoER2, little is known regarding how ApoER2 regulates APP trafficking and processing. Results Here, we demonstrate that ApoER2 physically interacts and co-localizes with APP. Remarkably, we found that ApoER2 increases cell surface APP levels and APP association with lipid rafts. The increase of cell surface APP requires the presence of ApoER2 cytoplasmic domain and is a result of decreased APP internalization rate. Unexpectedly, ApoER2 expression correlated with a significant increase in Aβ production and reduced levels of APP-CTFs. The increased Aβ production was dependent on the integrity of the NPxY endocytosis motif of ApoER2. We also found that expression of ApoER2 increased APP association with lipid rafts and increased γ-secretase activity, both of which might contribute to increased Aβ production. Conclusion These findings show that ApoER2 negatively affects APP internalization. However, ApoER2 expression stimulates Aβ production by shifting the proportion of APP from the non-rafts to the raft membrane domains, thereby promoting β-secretase and γ-secretase mediated amyloidogenic processing and also by incrementing the activity of γ-secretase.
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Affiliation(s)
- Rodrigo A Fuentealba
- FONDAP Center for Cell Regulation and Pathology (CRCP), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Maria Ines Barría
- FONDAP Center for Cell Regulation and Pathology (CRCP), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jiyeon Lee
- Departments of Pediatrics and Cell Biology & Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Judy Cam
- Departments of Pediatrics and Cell Biology & Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Claudia Araya
- FONDAP Center for Cell Regulation and Pathology (CRCP), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Claudia A Escudero
- FONDAP Center for Cell Regulation and Pathology (CRCP), Departamento de Ciencias Fisiológicas, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nibaldo C Inestrosa
- FONDAP Center for Cell Regulation and Pathology (CRCP), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Francisca C Bronfman
- FONDAP Center for Cell Regulation and Pathology (CRCP), Departamento de Ciencias Fisiológicas, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Guojun Bu
- Departments of Pediatrics and Cell Biology & Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Maria-Paz Marzolo
- FONDAP Center for Cell Regulation and Pathology (CRCP), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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Tuvia S, Taglicht D, Erez O, Alroy I, Alchanati I, Bicoviski V, Dori-Bachash M, Ben-Avraham D, Reiss Y. The ubiquitin E3 ligase POSH regulates calcium homeostasis through spatial control of Herp. ACTA ACUST UNITED AC 2007; 177:51-61. [PMID: 17420289 PMCID: PMC2064109 DOI: 10.1083/jcb.200611036] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The ubiquitin (Ub) domain protein Herp plays a crucial role in the maintenance of calcium homeostasis during endoplasmic reticulum (ER) stress. We now show that Herp is a substrate as well as an activator of the E3 Ub ligase POSH. Herp-mediated POSH activation requires the Ubl domain and exclusively promotes lysine-63-linked polyubiquitination. Confocal microscopy demonstrates that Herp resides mostly in the trans-Golgi network, but, shortly after calcium perturbation by thapsigargin (Tpg), it appears mainly in the ER. Substitution of all lysine residues within the Ubl domain abolishes lysine-63-linked polyubiquitination of Herp in vitro and calcium-induced Herp relocalization that is also abrogated by the overexpression of a dominant-negative POSHV14A. A correlation exists between the kinetics of Tpg-induced Herp relocalization and POSH-dependent polyubiquitination. Finally, the overexpression of POSH attenuates, whereas the inhibition of POSH by the expression of POSHV14A or by RNA interference enhances Tpg-induced calcium burst. Altogether, these results establish a critical role for POSH-mediated ubiquitination in the maintenance of calcium homeostasis through the spatial control of Herp.
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Affiliation(s)
- Shmuel Tuvia
- Proteologics Ltd., Kiryat Weizmann, Rehovot 76124, Israel
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Spasic D, Raemaekers T, Dillen K, Declerck I, Baert V, Serneels L, Füllekrug J, Annaert W. Rer1p competes with APH-1 for binding to nicastrin and regulates gamma-secretase complex assembly in the early secretory pathway. ACTA ACUST UNITED AC 2007; 176:629-40. [PMID: 17325205 PMCID: PMC2064021 DOI: 10.1083/jcb.200609180] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The γ-secretase complex, consisting of presenilin, nicastrin, presenilin enhancer-2 (PEN-2), and anterior pharynx defective-1 (APH-1) cleaves type I integral membrane proteins like amyloid precursor protein and Notch in a process of regulated intramembrane proteolysis. The regulatory mechanisms governing the multistep assembly of this “proteasome of the membrane” are unknown. We characterize a new interaction partner of nicastrin, the retrieval receptor Rer1p. Rer1p binds preferentially immature nicastrin via polar residues within its transmembrane domain that are also critical for interaction with APH-1. Absence of APH-1 substantially increased binding of nicastrin to Rer1p, demonstrating the competitive nature of these interactions. Moreover, Rer1p expression levels control the formation of γ-secretase subcomplexes and, concomitantly, total cellular γ-secretase activity. We identify Rer1p as a novel limiting factor that negatively regulates γ-secretase complex assembly by competing with APH-1 during active recycling between the endoplasmic reticulum (ER) and Golgi. We conclude that total cellular γ-secretase activity is restrained by a secondary ER control system that provides a potential therapeutic value.
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Affiliation(s)
- Dragana Spasic
- Laboratory for Membrane Trafficking, Center for Human Genetics, Katholieke Universiteit Leuven/Vlaams Instituut voor Biotechnologie, Gasthuisberg, Leuven, B-3000 Leuven, Belgium
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Hu Z, Zeng L, Huang Z, Zhang J, Li T. The Study of Golgi Apparatus in Alzheimer’s Disease. Neurochem Res 2007; 32:1265-77. [PMID: 17401657 DOI: 10.1007/s11064-007-9302-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Accepted: 01/30/2007] [Indexed: 10/23/2022]
Abstract
Alzheimer's disease is an irreversible, progressive neurodegenerative disorder leading invariably to death, usually within 7-10 years after diagnosis and is the leading cause of dementia in the elderly. Not only is Alzheimer's disease a tragic disease in which people suffer from neurodegeneration in the years to come, it also becomes an incredible burden on the public health system. However, there is currently no effective treatment to halt the progression or prevent the onset of Alzheimer's disease. This is partly due to the fact that the complex pathophysiology of Alzheimer's disease is not yet completely understood. Recently, Golgi apparatus is found to play an important role in Alzheimer's disease. In this review, we discuss the changes of Golgi apparatus during clinical progression and pathological development of Alzheimer's disease. First, changes of Golgi apparatus size in Alzheimer's disease are summarized. We then address the role of Golgi apparatus in the neuropathology of Alzheimer's disease. Finally, the role of Golgi apparatus in the pathogenesis of Alzheimer's disease is discussed. Understanding the contribution of Golgi apparatus dysfunction to Alzheimer's disease and its pathophysiological basis will significantly impact our ability to develop more effective therapies for Alzheimer's disease.
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Affiliation(s)
- Zhiping Hu
- Department of Neurology, Second Xiangya Hospital, Central South University, Changsha, China
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Selivanova A, Winblad B, Farmery MR, Dantuma NP, Ankarcrona M. COPI-mediated retrograde transport is required for efficient γ-secretase cleavage of the amyloid precursor protein. Biochem Biophys Res Commun 2006; 350:220-6. [PMID: 16999935 DOI: 10.1016/j.bbrc.2006.09.043] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2006] [Accepted: 09/09/2006] [Indexed: 11/30/2022]
Abstract
Sequential cleavage of the amyloid precursor protein (APP) by beta- and gamma-secretases results in the production of beta-amyloid peptide, which is a key determinant in Alzheimer's disease. Since several putative locations for gamma-secretase cleavage have been identified along the secretory pathway, trafficking of APP may be of importance for beta-amyloid peptide production. Here we have studied the role of retrograde transport in APP processing. We found that APP interacts with the beta subunit of the coatomer protein I (COPI) complex, which is involved in retrograde transport. In line with a role of retrograde trafficking in APP transport, inhibition of COPI-dependent transport altered APP trafficking, decreased APP cell surface expression, and coincided with a profound reduction in gamma-secretase cleavage. These results suggest that COPI-dependent retrograde transport is important for APP processing and influences production of beta-amyloid peptide.
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Affiliation(s)
- Alexandra Selivanova
- Department of Neurobiology, Caring Sciences and Society (NVS), KI Alzheimer Disease Research Center, Karolinska Institutet, Novum 5th floor, S-141 57 Stockholm, Sweden.
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35
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Spasic D, Tolia A, Dillen K, Baert V, De Strooper B, Vrijens S, Annaert W. Presenilin-1 Maintains a Nine-Transmembrane Topology throughout the Secretory Pathway. J Biol Chem 2006; 281:26569-77. [PMID: 16846981 DOI: 10.1074/jbc.m600592200] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Presenilin-1 is a polytopic membrane protein that assembles with nicastrin, PEN-2, and APH-1 into an active gamma-secretase complex required for intramembrane proteolysis of type I transmembrane proteins. Although essential for a correct understanding of structure-function relationships, its exact topology remains an issue of strong controversy. We revisited presenilin-1 topology by inserting glycosylation consensus sequences in human PS1 and expressing the obtained mutants in a presenilin-1 and 2 knock-out background. Based on the glycosylation status of these variants we provide evidence that presenilin-1 traffics through the Golgi after a conformational change induced by complex assembly. Based on our glycosylation variants of presenilin-1 we hypothesize that complex assembly occurs during transport between the endoplasmic reticulum and the Golgi apparatus. Furthermore, our data indicate that presenilin-1 has a nine-transmembrane domain topology with the COOH terminus exposed to the lumen/extracellular surface. This topology is independently underscored by lysine mutagenesis, cell surface biotinylation, and cysteine derivation strategies and is compatible with the different physiological functions assigned to presenilin-1.
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Affiliation(s)
- Dragana Spasic
- Laboratory of Membrane Trafficking, Department of Human Genetics, Gasthuisberg, Katholieke Universiteit Leuven/VIB11, B-3000 Leuven, Belgium
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Rajendran L, Honsho M, Zahn TR, Keller P, Geiger KD, Verkade P, Simons K. Alzheimer's disease beta-amyloid peptides are released in association with exosomes. Proc Natl Acad Sci U S A 2006; 103:11172-7. [PMID: 16837572 PMCID: PMC1544060 DOI: 10.1073/pnas.0603838103] [Citation(s) in RCA: 996] [Impact Index Per Article: 55.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Although the exact etiology of Alzheimer's disease (AD) is a topic of debate, the consensus is that the accumulation of beta-amyloid (Abeta) peptides in the senile plaques is one of the hallmarks of the progression of the disease. The Abeta peptide is formed by the amyloidogenic cleavage of the amyloid precursor protein (APP) by beta- and gamma-secretases. The endocytic system has been implicated in the cleavages leading to the formation of Abeta. However, the identity of the intracellular compartment where the amyloidogenic secretases cleave and the mechanism by which the intracellularly generated Abeta is released into the extracellular milieu are not clear. Here, we show that beta-cleavage occurs in early endosomes followed by routing of Abeta to multivesicular bodies (MVBs) in HeLa and N2a cells. Subsequently, a minute fraction of Abeta peptides can be secreted from the cells in association with exosomes, intraluminal vesicles of MVBs that are released into the extracellular space as a result of fusion of MVBs with the plasma membrane. Exosomal proteins were found to accumulate in the plaques of AD patient brains, suggesting a role in the pathogenesis of AD.
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Affiliation(s)
- Lawrence Rajendran
- *Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Masanori Honsho
- *Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Tobias R. Zahn
- *Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | | | - Kathrin D. Geiger
- Department of Neuropathology, Institute of Pathology, University Clinic, University of Technology, 01307 Dresden, Germany
| | - Paul Verkade
- *Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Kai Simons
- *Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
- To whom correspondence should be addressed. E-mail:
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Vetrivel KS, Zhang YW, Xu H, Thinakaran G. Pathological and physiological functions of presenilins. Mol Neurodegener 2006; 1:4. [PMID: 16930451 PMCID: PMC1513131 DOI: 10.1186/1750-1326-1-4] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Accepted: 06/12/2006] [Indexed: 11/16/2022] Open
Abstract
Mutations in PSEN1 and PSEN2 genes account for the majority of cases of early-onset familial Alzheimer disease. Since the first prediction of a genetic link between PSEN1 and PSEN2 with Alzheimer's disease, many research groups from both academia and pharmaceutical industry have sought to unravel how pathogenic mutations in PSEN cause presenile dementia. PSEN genes encode polytopic membrane proteins termed presenilins (PS1 and PS2), which function as the catalytic subunit of γ-secretase, an intramembrane protease that has a wide spectrum of type I membrane protein substrates. Sequential cleavage of amyloid precursor protein by BACE and γ-secretase releases highly fibrillogenic β-amyloid peptides, which accumulate in the brains of aged individuals and patients with Alzheimer's disease. Familial Alzheimer's disease-associated presenilin variants are thought to exert their pathogenic function by selectively elevating the levels of highly amyloidogenic Aβ42 peptides. In addition to Alzheimer's disease, several recent studies have linked PSEN1 to familiar frontotemporal dementia. Here, we review the biology of PS1, its role in γ-secretase activity, and discuss recent developments in the cell biology of PS1 with respect to Alzheimer's disease pathogenesis.
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Affiliation(s)
- Kulandaivelu S Vetrivel
- Department of Neurobiology, Pharmacology and Physiology, The University of Chicago, Chicago, IL 60637, USA
| | - Yun-wu Zhang
- Center for Neuroscience and Aging, Burnham Institute for Medical Research, LaJolla, CA 92037, USA
| | - Huaxi Xu
- Center for Neuroscience and Aging, Burnham Institute for Medical Research, LaJolla, CA 92037, USA
| | - Gopal Thinakaran
- Department of Neurobiology, Pharmacology and Physiology, The University of Chicago, Chicago, IL 60637, USA
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38
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Zhang M, Haapasalo A, Kim DY, Ingano LAM, Pettingell WH, Kovacs DM. Presenilin/γ‐secretase activity regulates protein clearance from the endocytic recycling compartment. FASEB J 2006; 20:1176-8. [PMID: 16645046 DOI: 10.1096/fj.05-5531fje] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The presenilin (PS)/gamma-secretase complex proteolytically cleaves more than 20 different proteins in addition to the amyloid precursor protein (APP). These substrates are almost exclusively type I membrane proteins. Many undergo internalization from the cell surface followed by degradation or recycling back to the plasma membrane through the endocytic recycling compartment (ERC). Evidence shows that the PSs also regulate intracellular trafficking of APP and its C-terminal fragments (CTFs). To investigate whether PS/gamma-secretase activity is required for normal endosomal recycling, we performed live cell imaging experiments with fluorescently labeled transferrin, reported to specifically traffic through the ERC. By using pharmacological gamma-secretase inhibitors or cell lines lacking functional PS/gamma-secretase, here we show that PS/gamma-secretase activity is required for clearance of transferrin from the ERC. Interestingly, lack of PS/gamma-secretase function also resulted in the accumulation of APP and APP-CTFs in the ERC in addition to the cell surface. Familial Alzheimer's disease mutations in APP-CTFs did not affect endocytic recycling of these proteins. Our results suggest that PS/gamma-secretase activity is required for normal endosomal recycling of soluble and membrane-associated proteins through the ERC and propose a new mechanism by which impaired PS/gamma-secretase function may eventually contribute to neurodegeneration.
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Affiliation(s)
- Mei Zhang
- Neurobiology of Disease Laboratory, Genetics and Aging Research Unit, Department of Neurology/MIND, Massachusetts General Hospital, Harvard Medical School, 114 16th Street, Charlestown, Massachusetts 02129, USA
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Massey L, Mah A, Monteiro M. Ubiquilin regulates presenilin endoproteolysis and modulates gamma-secretase components, Pen-2 and nicastrin. Biochem J 2006; 391:513-25. [PMID: 15975090 PMCID: PMC1276952 DOI: 10.1042/bj20050491] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mutations in presenilin proteins (PS1 and PS2) lead to early-onset Alzheimer's disease. PS proteins are endoproteolytically cleaved into two main fragments: the NTF (PS N-terminal fragment) and the CTF (PS C-terminal fragment). The two fragments are believed to constitute the core catalytic enzyme activity called gamma-secretase, which is responsible for cleaving beta-amyloid precursor protein to release Abeta. Thus, studying factors that modulate PS fragment levels could provide important information about gamma-secretase. Previously, we demonstrated that the protein, ubiquilin-1, interacts both in vivo and in vitro with PS and that overexpression of ubiquilin-1 or -2 leads to increased accumulation of full-length PS proteins. Using wild-type HEK-293 cells (human embryonic kidney 293 cells) and PS-inducible cells, we now show that overexpression of either ubiquilin-1 or -2 decreases the PS NTF and CTF levels. Conversely, siRNA (small interfering RNA)-mediated knockdown of ubiquilin-1 and -2 proteins increased the PS NTF and CTF levels. We considered that ubiquilin might alter PS fragment accumulation by acting as a shuttle factor escorting PS fragments to the proteasome for degradation. However, through proteasome inhibition studies, we show that this does not occur. Instead, our results suggest that ubiquilin regulates PS fragment production. We also examined whether other components of the gamma-secretase complex are affected by ubiquilin expression. Interestingly, overexpression of ubiquilin resulted in a decrease in Pen-2 and nicastrin levels, two essential components of the gamma-secretase complex. In contrast, knockdown of ubiquilin-1 and -2 protein expression by RNAi (RNA interference) increased Pen-2 and nicastrin levels. Finally, we show that inhibition of the proteasome results in decreased PS fragment production and that reversal of proteasome inhibition restores PS fragment production, suggesting that the proteasome may be involved in PS endoproteolysis. These studies implicate ubiquilin as an important factor in regulating PS biogenesis and metabolism.
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Affiliation(s)
- Leann K. Massey
- *Molecular and Cell Biology Graduate Program, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201, U.S.A
| | - Alex L. Mah
- *Molecular and Cell Biology Graduate Program, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201, U.S.A
| | - Mervyn J. Monteiro
- *Molecular and Cell Biology Graduate Program, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201, U.S.A
- †Medical Biotechnology Center, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201, U.S.A
- To whom correspondence should be addressed (email )
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40
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Kaether C, Schmitt S, Willem M, Haass C. Amyloid Precursor Protein and Notch Intracellular Domains are Generated after Transport of their Precursors to the Cell Surface. Traffic 2006; 7:408-15. [PMID: 16536739 DOI: 10.1111/j.1600-0854.2006.00396.x] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Alzheimer's disease is characterized by brain deposition of extracellular amyloid beta-peptide (Abeta)-containing plaques. The cellular site of gamma-secretase activity, which releases Abeta and the corresponding amyloid precursor protein intracellular domain (AICD), remains controversial. Proposed cleavage sites range from the endoplasmic reticulum (ER), the Golgi apparatus, and the cell surface to endosomal compartments. We now used C99-green fluorescent protein (GFP), a fluorescent reporter substrate for gamma-secretase activity and monitored AICD production in living cells. C99-GFP is efficiently cleaved by gamma-secretase, and AICD-GFP is released into the cytosol. Inhibiting gamma-secretase results in accumulation of C99-GFP in early endosomes. By blocking selective transport steps along the secretory pathway, we demonstrate that gamma-secretase does not cleave its substrates in the ER, the Golgi/trans-Golgi network, or in secretory vesicles. In contrast, inhibition of endocytosis did not inhibit cleavage of C99-GFP. Similar results were obtained for another gamma-secretase substrate, NotchDeltaE. Our results suggest that intracellular domains are generated by gamma-secretase at the plasma membrane and/or early endosomes.
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Affiliation(s)
- Christoph Kaether
- Department of Biochemistry, Adolf-Butenandt-Institute, Laboratory for Alzheimer's and Parkinson's Disease Research, Ludwig-Maximilians-University, 80336 München, Germany
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Réchards M, Xia W, Oorschot V, van Dijk S, Annaert W, Selkoe DJ, Klumperman J. Presenilin-1-mediated Retention of APP Derivatives in Early Biosynthetic Compartments. Traffic 2006; 7:354-64. [PMID: 16497228 DOI: 10.1111/j.1600-0854.2006.00388.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Processing of the amyloid precursor protein (APP) leads to the production of amyloid-beta (Abeta), the major component of extracellular plaques in the brains of Alzheimer's disease (AD) patients. Presenilin-1 (PS-1) plays a key role in the final step of Abeta formation, the gamma-secretase cleavage. Previously, we showed that PS-1 is retained in pre-Golgi compartments by incorporation into COPI-coated membranes of the vesicular tubular clusters (VTCs) between endoplasmic reticulum (ER) and Golgi complex. Here, we show that PS-1 also mediates the retention of the beta-cleavage-derived APP-C-terminal fragment (CTFbeta) and/or Abeta in pre-Golgi membranes. Overexpression of PS-1 increased the percentage of CTFbeta and/or Abeta in VTCs as well as their distribution to COPI-coated VTC membranes. By contrast, overexpression of the dominant-negative aspartate mutant PS-1(D257A) or PS-knockout decreased incorporation of these APP derivatives into COPI-coated membranes. Sorting of APP derivatives to COPI-coated VTC membranes was not depending on the APP cytosolic tail. In post-Golgi compartments, PS-1 expression enhanced the association of full-length APP/APPs with endosomal compartments at the expense of plasma membrane-bound APP. We conclude that PS-1, in addition to its role in gamma-secretase cleavage, is also required for the subcellular routing of APP and its derivatives. Malfunctioning of PS-1 in this role may have important consequences for the progress of AD.
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Affiliation(s)
- Marloes Réchards
- Cell Microscopy Center, Department of Cell Biology, University Medical Center and Institute for Biomembranes, 3584 CX Utrecht, the Netherlands
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Dillen K, Annaert W. A Two Decade Contribution of Molecular Cell Biology to the Centennial of Alzheimer's Disease: Are We Progressing Toward Therapy? INTERNATIONAL REVIEW OF CYTOLOGY 2006; 254:215-300. [PMID: 17148000 DOI: 10.1016/s0074-7696(06)54005-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Alzheimer's disease (AD), described for the first time 100 years ago, is a neurodegenerative disease characterized by two neuropathological hallmarks: neurofibrillary tangles containing hyperphosphorylated tau and senile plaques. These lesions are likely initiated by an imbalance between production and clearance of amyloid beta, leading to increased oligomerization of these peptides, formation of amyloid plaques in the brain of the patient, and final dementia. Amyloid beta is generated from amyloid precursor protein (APP) by subsequent beta- and gamma-secretase cleavage, the latter being a multiprotein complex consisting of presenilin-1 or -2, nicastrin, APH-1, and PEN-2. Alternatively, APP can be cleaved by alpha- and gamma-secretase, precluding the production of Abeta. In this review, we discuss the major breakthroughs during the past two decades of molecular cell biology and the current genetic and cell biological state of the art on APP proteolysis, including structure-function relationships and subcellular localization. Finally, potential directions for cell biological research toward the development of AD therapies are briefly discussed.
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Affiliation(s)
- Katleen Dillen
- Laboratory for Membrane Trafficking, Center for Human Genetics/VIB1104 & KULeuven, Gasthuisberg O&N1, B-3000 Leuven, Belgium
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Brunkan AL, Martinez M, Wang J, Walker ES, Goate AM. A domain at the C-terminus of PS1 is required for presenilinase and γ-secretase activities. J Neurochem 2005; 92:1158-69. [PMID: 15715666 DOI: 10.1111/j.1471-4159.2004.02945.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The structural requirements for presenilin (PS) to produce active presenilinase and gamma-secretase enzymes are poorly understood. Here we investigate the role the cytoplasmic C-terminal region of PS1 plays in PS1 activity. Deletion or addition of residues at the PS C-terminus has been reported to inhibit presenilinase endoproteolysis of PS and alter gamma-secretase activity. In this study, we use a sensitive assay in PS1/2KO MEFs to define a domain at the extreme C-terminus of PS1 that is essential for both presenilinase and gamma-secretase activities. Progressive deletion of the C-terminus demonstrated that removal of nine residues produces a PS1 molecule (458ST) that lacks both presenilinase processing and gamma-secretase cleavage of Notch and APP substrates. In contrast, removal of four or five residues had no effect (462ST, 463ST), while intermediate truncations partially inhibited PS1 activity. The 458ST mutant was unable to replace endogenous wtPS1 in HEK293 cells. Although 458ST was able to form a gamma-secretase complex, this complex was not matured, illustrated by mutant PS1 instability, lack of endoproteolysis, and little production of mature Nicastrin. These data indicate that the C-terminal end of PS1 is essential for Nicastrin trafficking and modification as well as the replacement of endogenous PS1 by PS1 transgenes.
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Affiliation(s)
- A L Brunkan
- Department of Psychiatry, Washington University School of Medicine, 660 S.Euclid B8134, St Louis, Mo 63110, Missouri, USA
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Esselens C, Oorschot V, Baert V, Raemaekers T, Spittaels K, Serneels L, Zheng H, Saftig P, De Strooper B, Klumperman J, Annaert W. Presenilin 1 mediates the turnover of telencephalin in hippocampal neurons via an autophagic degradative pathway. ACTA ACUST UNITED AC 2004; 166:1041-54. [PMID: 15452145 PMCID: PMC2172014 DOI: 10.1083/jcb.200406060] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Presenilin 1 (PS1) interacts with telencephalin (TLN) and the amyloid precursor protein via their transmembrane domain (Annaert, W.G., C. Esselens, V. Baert, C. Boeve, G. Snellings, P. Cupers, K. Craessaerts, and B. De Strooper. 2001. Neuron. 32:579–589). Here, we demonstrate that TLN is not a substrate for γ-secretase cleavage, but displays a prolonged half-life in PS1−/− hippocampal neurons. TLN accumulates in intracellular structures bearing characteristics of autophagic vacuoles including the presence of Apg12p and LC3. Importantly, the TLN accumulations are suppressed by adenoviral expression of wild-type, FAD-linked and D257A mutant PS1, indicating that this phenotype is independent from γ-secretase activity. Cathepsin D deficiency also results in the localization of TLN to autophagic vacuoles. TLN mediates the uptake of microbeads concomitant with actin and PIP2 recruitment, indicating a phagocytic origin of TLN accumulations. Absence of endosomal/lysosomal proteins suggests that the TLN-positive vacuoles fail to fuse with endosomes/lysosomes, preventing their acidification and further degradation. Collectively, PS1 deficiency affects in a γ-secretase–independent fashion the turnover of TLN through autophagic vacuoles, most likely by an impaired capability to fuse with lysosomes.
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Affiliation(s)
- Cary Esselens
- Membrane Trafficking Laboratory, CME-VIB04, Gasthuisberg-KU Leuven, 3000 Leuven, Belgium
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Chyung JH, Raper DM, Selkoe DJ. Gamma-secretase exists on the plasma membrane as an intact complex that accepts substrates and effects intramembrane cleavage. J Biol Chem 2004; 280:4383-92. [PMID: 15569674 DOI: 10.1074/jbc.m409272200] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Research on Alzheimer's disease led to the identification of a novel proteolytic mechanism in all metazoans, the presenilin/gamma-secretase complex. This unique intramembrane-cleaving aspartyl protease is required for the normal processing of Notch, Jagged, beta-amyloid precursor protein (APP), E-cadherin, and many other receptor-like proteins. We recently provided indirect evidence of gamma-secretase activity at the cell surface in HeLa cells following inhibition of receptor-mediated endocytosis. Here, we directly identify and isolate gamma-secretase as an intact complex (Presenilin, Nicastrin, Aph-1, and Pen-2) from the plasma membrane, both in overexpressing cell lines and endogenously. Inhibition of its proteolytic activity allowed cell surface gamma-secretase to be captured in association with its plasma membrane-localized APP substrates (C83 and C99). Moreover, non-denaturing isolation of the intact enzyme complex revealed that cell surface gamma-secretase can specifically generate amyloid beta-protein from an APP substrate and similarly cleave a Notch substrate. These data directly establish the proteolytic function of gamma-secretase on the plasma membrane, independent of a hypothesized substrate trafficking role. We conclude that presenilin/gamma-secretase exists as a mature complex at the cell surface, where it interacts with and can cleave its substrates, consistent with an essential function in processing many adhesion molecules and receptors required for cell-cell interaction or intercellular signaling.
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Affiliation(s)
- Jay H Chyung
- Center for Neurologic Diseases, Brigham & Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
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Tarassishin L, Yin YI, Bassit B, Li YM. Processing of Notch and amyloid precursor protein by gamma-secretase is spatially distinct. Proc Natl Acad Sci U S A 2004; 101:17050-5. [PMID: 15563588 PMCID: PMC535399 DOI: 10.1073/pnas.0408007101] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
gamma-Secretase activity is associated with a presenilin (PS)-containing macromolecular complex. Whether PS contains the active site of gamma-secretase has been controversial. One challenge is to find PS that is engaged in the active gamma-secretase complex at the cell surface, where some substrates appear to be processed. In this study, we developed an intact cell photolabeling technique that allows the direct visualization of active gamma-secretase at the cell surface. We demonstrated that active gamma-secretase is present in the plasma membrane. Moreover, the PS1 heterodimer is specifically photolabeled at the cell surface by a potent inhibitor that binds to only the active gamma-secretase. We also explored the cellular processing sites of gamma-secretase for amyloid precursor protein (APP) and Notch by using small molecular probes. MRL631, a gamma-secretase inhibitor that is unable to penetrate the cell membrane, significantly blocks gamma-secretase-mediated Notch cleavage but has little effect on APP processing. These results indicate that Notch is processed at the cell surface and that the majority of APP is processed by intracellular gamma-secretase. Furthermore, the fact that inhibitors first target gamma-secretase in the plasma membrane for Notch processing, and not for APP, will have important implications for drug development to treat Alzheimer's disease and cancer.
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Affiliation(s)
- Leonid Tarassishin
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
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Vetrivel KS, Cheng H, Lin W, Sakurai T, Li T, Nukina N, Wong PC, Xu H, Thinakaran G. Association of gamma-secretase with lipid rafts in post-Golgi and endosome membranes. J Biol Chem 2004; 279:44945-54. [PMID: 15322084 PMCID: PMC1201506 DOI: 10.1074/jbc.m407986200] [Citation(s) in RCA: 333] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Alzheimer's disease-associated beta-amyloid peptides (Abeta) are generated by the sequential proteolytic processing of amyloid precursor protein (APP) by beta- and gamma-secretases. There is growing evidence that cholesterol- and sphingolipid-rich membrane microdomains are involved in regulating trafficking and processing of APP. BACE1, the major beta-secretase in neurons is a palmitoylated transmembrane protein that resides in lipid rafts. A subset of APP is subject to amyloidogenic processing by BACE1 in lipid rafts, and this process depends on the integrity of lipid rafts. Here we describe the association of all four components of the gamma-secretase complex, namely presenilin 1 (PS1)-derived fragments, mature nicastrin, APH-1, and PEN-2, with cholesterol-rich detergent insoluble membrane (DIM) domains of non-neuronal cells and neurons that fulfill the criteria of lipid rafts. In PS1(-/-)/PS2(-/-) and NCT(-/-) fibroblasts, gamma-secretase components that still remain fail to become detergent-resistant, suggesting that raft association requires gamma-secretase complex assembly. Biochemical evidence shows that subunits of the gamma-secretase complex and three TGN/endosome-resident SNAREs cofractionate in sucrose density gradients, and show similar solubility or insolubility characteristics in distinct non-ionic and zwitterionic detergents, indicative of their co-residence in membrane microdomains with similar protein-lipid composition. This notion is confirmed using magnetic immunoisolation of PS1- or syntaxin 6-positive membrane patches from a mixture of membranes with similar buoyant densities following Lubrol WX extraction or sonication, and gradient centrifugation. These findings are consistent with the localization of gamma-secretase in lipid raft microdomains of post-Golgi and endosomes, organelles previously implicated in amyloidogenic processing of APP.
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Affiliation(s)
| | - Haipeng Cheng
- From the Department of Neurobiology, Pharmacology and Physiology and the
| | - William Lin
- Committee on Neurobiology, The University of Chicago, Chicago, Illinois 60637, the
| | - Takashi Sakurai
- Laboratory for Neurodegeneration Signal and Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, 351-0198, Japan, the
| | - Tong Li
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, and the
| | - Nobuyuki Nukina
- Laboratory for Neurodegeneration Signal and Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, 351-0198, Japan, the
| | - Philip C. Wong
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, and the
| | - Huaxi Xu
- Center for Neuroscience and Aging, The Burnham Institute, La Jolla, California 92037
| | - Gopal Thinakaran
- From the Department of Neurobiology, Pharmacology and Physiology and the
- Committee on Neurobiology, The University of Chicago, Chicago, Illinois 60637, the
- §§ To whom correspondence should be addressed. Tel.: 773-834-3752; Fax: 773-834-3808; E-mail:
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