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Tambini MD, Yin T, Yesiltepe M, Breuillaud L, Zehntner SP, d'Abramo C, Giliberto L, D'Adamio L. Aβ43 levels determine the onset of pathological amyloid deposition. J Biol Chem 2023; 299:104868. [PMID: 37257821 PMCID: PMC10404620 DOI: 10.1016/j.jbc.2023.104868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 04/18/2023] [Accepted: 05/22/2023] [Indexed: 06/02/2023] Open
Abstract
About 2% of Alzheimer's disease (AD) cases have early onset (FAD) and are caused by mutations in either Presenilins (PSEN1/2) or amyloid-β precursor protein (APP). PSEN1/2 catalyze production of Aβ peptides of different length from APP. Aβ peptides are the major components of amyloid plaques, a pathological lesion that characterizes AD. Analysis of mechanisms by which PSEN1/2 and APP mutations affect Aβ peptide compositions lead to the implication of the absolute or relative increase in Aβ42 in amyloid-β plaques formation. Here, to elucidate the formation of pathogenic Aβ cocktails leading to amyloid pathology, we utilized FAD rat knock-in models carrying the Swedish APP (Apps allele) and the PSEN1 L435F (Psen1LF allele) mutations. To accommodate the differences in the pathogenicity of rodent and human Aβ, these rat models are genetically engineered to express human Aβ species as both the Swedish mutant allele and the WT rat allele (called Apph) have been humanized in the Aβ-coding region. Analysis of the eight possible FAD mutant permutations indicates that the CNS levels of Aβ43, rather than absolute or relative increases in Aβ42, determine the onset of pathological amyloid deposition in FAD knock-in rats. Notably, Aβ43 was found in amyloid plaques in late onset AD and mild cognitive impairment cases, suggesting that the mechanisms initiating amyloid pathology in FAD knock-in rat reflect disease mechanisms driving amyloid pathology in late onset AD. This study helps clarifying the molecular determinants initiating amyloid pathology and supports therapeutic interventions targeting Aβ43 in AD.
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Affiliation(s)
- Marc D Tambini
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Tao Yin
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Metin Yesiltepe
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | | | | | - Cristina d'Abramo
- Litwin-Zucker Center for the Study of Alzheimer's Disease and Memory Disorders, Feinstein Institutes for Medical Research, Institute of Molecular Medicine, Northwell Health System, Manhasset, New York, USA
| | - Luca Giliberto
- Litwin-Zucker Center for the Study of Alzheimer's Disease and Memory Disorders, Feinstein Institutes for Medical Research, Institute of Molecular Medicine, Northwell Health System, Manhasset, New York, USA; Institute of Neurology and Neurosurgery, Northwell Health System, Manhasset, New York, USA
| | - Luciano D'Adamio
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA.
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2
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Do HN, Devkota S, Bhattarai A, Wolfe MS, Miao Y. Effects of presenilin-1 familial Alzheimer's disease mutations on γ-secretase activation for cleavage of amyloid precursor protein. Commun Biol 2023; 6:174. [PMID: 36788318 PMCID: PMC9929099 DOI: 10.1038/s42003-023-04539-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 01/30/2023] [Indexed: 02/16/2023] Open
Abstract
Presenilin-1 (PS1) is the catalytic subunit of γ-secretase which cleaves within the transmembrane domain of over 150 peptide substrates. Dominant missense mutations in PS1 cause early-onset familial Alzheimer's disease (FAD); however, the exact pathogenic mechanism remains unknown. Here we combined Gaussian accelerated molecular dynamics (GaMD) simulations and biochemical experiments to determine the effects of six representative PS1 FAD mutations (P117L, I143T, L166P, G384A, L435F, and L286V) on the enzyme-substrate interactions between γ-secretase and amyloid precursor protein (APP). Biochemical experiments showed that all six PS1 FAD mutations rendered γ-secretase less active for the endoproteolytic (ε) cleavage of APP. Distinct low-energy conformational states were identified from the free energy profiles of wildtype and PS1 FAD-mutant γ-secretase. The P117L and L286V FAD mutants could still sample the "Active" state for substrate cleavage, but with noticeably reduced conformational space compared with the wildtype. The other mutants hardly visited the "Active" state. The PS1 FAD mutants were found to reduce γ-secretase proteolytic activity by hindering APP residue L49 from proper orientation in the active site and/or disrupting the distance between the catalytic aspartates. Therefore, our findings provide mechanistic insights into how PS1 FAD mutations affect structural dynamics and enzyme-substrate interactions of γ-secretase and APP.
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Affiliation(s)
- Hung N. Do
- grid.266515.30000 0001 2106 0692Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66047 USA
| | - Sujan Devkota
- grid.266515.30000 0001 2106 0692Department of Medicinal Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS 66047 USA
| | - Apurba Bhattarai
- grid.266515.30000 0001 2106 0692Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66047 USA
| | - Michael S. Wolfe
- grid.266515.30000 0001 2106 0692Department of Medicinal Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS 66047 USA
| | - Yinglong Miao
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS, 66047, USA.
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Willumsen N, Arber C, Lovejoy C, Toombs J, Alatza A, Weston PSJ, Chávez-Gutiérrez L, Hardy J, Zetterberg H, Fox NC, Ryan NS, Lashley T, Wray S. The PSEN1 E280G mutation leads to increased amyloid-β43 production in induced pluripotent stem cell neurons and deposition in brain tissue. Brain Commun 2022; 5:fcac321. [PMID: 36687397 PMCID: PMC9847549 DOI: 10.1093/braincomms/fcac321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 09/06/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
Mutations in the presenilin 1 gene, PSEN1, which cause familial Alzheimer's disease alter the processing of amyloid precursor protein, leading to the generation of various amyloid-β peptide species. These species differ in their potential for aggregation. Mutation-specific amyloid-β peptide profiles may thereby influence pathogenicity and clinical heterogeneity. There is particular interest in comparing mutations with typical and atypical clinical presentations, such as E280G. We generated PSEN1 E280G mutation induced pluripotent stem cells from two patients and differentiated them into cortical neurons, along with previously reported PSEN1 M146I, PSEN1 R278I and two control lines. We assessed both the amyloid-β peptide profiles and presenilin 1 protein maturity. We also compared amyloid-β peptide profiles in human post-mortem brain tissue from cases with matched mutations. Amyloid-β ratios significantly differed compared with controls and between different patients, implicating mutation-specific alterations in amyloid-β ratios. Amyloid-β42:40 was increased in the M146I and both E280G lines compared with controls. Amyloid-β42:40 was not increased in the R278I line compared with controls. The amyloid-β43:40 ratio was increased in R278I and both E280G lines compared with controls, but not in M146I cells. Distinct amyloid-β peptide patterns were also observed in human brain tissue from individuals with these mutations, showing some similar patterns to cell line observations. Reduced presenilin 1 maturation was observed in neurons with the PSEN1 R278I and E280G mutations, but not the M146I mutation. These results suggest that mutation location can differentially alter the presenilin 1 protein and affect its autoendoproteolysis and processivity, contributing to the pathological phenotype. Investigating differences in underlying molecular mechanisms of familial Alzheimer's disease may inform our understanding of clinical heterogeneity.
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Affiliation(s)
- Nanet Willumsen
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 1PJ, UK
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, London WC1N 1PJ, UK
| | - Charles Arber
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 1PJ, UK
| | - Christopher Lovejoy
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 1PJ, UK
| | - Jamie Toombs
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 1PJ, UK
- UK Dementia Research Institute, University College London, London WC1E 6AU, UK
| | - Argyro Alatza
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 1PJ, UK
| | - Philip S J Weston
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 1PJ, UK
- Dementia Research Centre, UCL Queen Square Institute of Neurology, London WC1E 6BT, UK
| | - Lucia Chávez-Gutiérrez
- VIB Center for Brain and Disease Research, 3000 Leuven, Belgium
- Department of Neurology, KU Leuven, 3000 Leuven, Belgium
| | - John Hardy
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 1PJ, UK
- UK Dementia Research Institute, University College London, London WC1E 6AU, UK
| | - Henrik Zetterberg
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 1PJ, UK
- UK Dementia Research Institute, University College London, London WC1E 6AU, UK
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, S-431 80 Mölndal, Sweden
| | - Nick C Fox
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 1PJ, UK
- Dementia Research Centre, UCL Queen Square Institute of Neurology, London WC1E 6BT, UK
- UK Dementia Research Institute, University College London, London WC1E 6AU, UK
| | - Natalie S Ryan
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 1PJ, UK
- Dementia Research Centre, UCL Queen Square Institute of Neurology, London WC1E 6BT, UK
- UK Dementia Research Institute, University College London, London WC1E 6AU, UK
| | - Tammaryn Lashley
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 1PJ, UK
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, London WC1N 1PJ, UK
| | - Selina Wray
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 1PJ, UK
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Switched Aβ43 generation in familial Alzheimer's disease with presenilin 1 mutation. Transl Psychiatry 2021; 11:558. [PMID: 34728605 PMCID: PMC8564532 DOI: 10.1038/s41398-021-01684-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 10/14/2021] [Accepted: 10/20/2021] [Indexed: 11/24/2022] Open
Abstract
Presenilin (PS) with a genetic mutation generates abundant β-amyloid protein (Aβ) 43. Senile plaques are formed by Aβ43 in the cerebral parenchyma together with Aβ42 at middle ages. These brains cause the early onset of Alzheimer's disease (AD), which is known as familial Alzheimer's disease (FAD). Based on the stepwise processing model of Aβ generation by γ-secretase, we reassessed the levels of Aβs in the cerebrospinal fluid (CSF) of FAD participants. While low levels of Aβ38, Aβ40, and Aβ42 were generated in the CSF of FAD participants, the levels of Aβ43 were unchanged in some of them compared with other participants. We sought to investigate why the level of Aβ43 was unchanged in FAD participants. These characteristics of Aβ generation were observed in the γ-secretase assay in vitro using cells, which express FAD mutations in PS1. Aβ38 and Aβ40 generation from their precursors, Aβ42 and Aβ43, was decreased in PS1 mutants compared with wild-type (WT) PS1, as observed in the CSF. Both the ratios of Aβ38/Aβ42 and Aβ40/Aβ43 in PS1 mutants were lower than those in the WT. However, the ratio of Aβ43/amyloid precursor protein intracellular domain (AICD) increased in the PS1 mutants in an onset age dependency, while other Aβ/AICD ratios were decreased or unchanged. Importantly, liquid chromatography-mass spectrometry found that the generation of Aβ43 was stimulated from Aβ48 in PS1 mutants. This result indicates that PS1 mutants switched the Aβ43 generating line, which reflects the level of Aβ43 in the CSF and forming senile plaques.
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Watanabe N, Nakano M, Mitsuishi Y, Hara N, Mano T, Iwata A, Murayama S, Suzuki T, Ikeuchi T, Nishimura M. Transcriptional downregulation of FAM3C/ILEI in the Alzheimer's brain. Hum Mol Genet 2021; 31:122-132. [PMID: 34378027 DOI: 10.1093/hmg/ddab226] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 07/29/2021] [Accepted: 08/02/2021] [Indexed: 11/14/2022] Open
Abstract
Amyloid-β (Aβ) accumulation in the brain triggers the pathogenic cascade for Alzheimer's disease (AD) development. The secretory protein FAM3C (also named ILEI) is a candidate for an endogenous suppressor of Aβ production. In this study, we found that FAM3C expression was transcriptionally downregulated in the AD brain. To determine the transcriptional mechanism of the human FAM3C gene, we delineated the minimal 5'-flanking sequence required for basal promoter activity. From a database search for DNA-binding motifs, expression analysis using cultured cells, and promoter DNA-binding assays, we identified SP1 and EBF1 as candidate basal transcription factors for FAM3C, and found that SMAD1 was a putative inducible transcription factor and KLF6 was a transcription repressor for FAM3C. Genomic deletion of the basal promoter sequence from HEK293 and Neuro-2a cells markedly reduced endogenous expression of FAM3C and abrogated SP1- or EBF1-mediated induction of FAM3C. Nuclear protein extracts from AD brains contained lower levels of SP1 and EBF1 than did those from control brains, although the relative mRNA levels of these factors did not differ significantly between the groups. Additionally, the ability of nuclear SP1 and EBF1 in AD brains to bind with the basal promoter sequence-containing DNA probe was reduced compared with the binding ability of these factors in control brains. Thus, the transcriptional downregulation of FAM3C in the AD brain is attributable to the reduced nuclear levels and genomic DNA binding of SP1 and EBF1. An expressional decline in FAM3C may be a risk factor for Aβ accumulation and eventually AD development.
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Affiliation(s)
- Naoki Watanabe
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Shiga 520-2192, Japan
| | - Masaki Nakano
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Shiga 520-2192, Japan
| | - Yachiyo Mitsuishi
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Shiga 520-2192, Japan
| | - Norikazu Hara
- Department of Molecular Genetics, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Tatsuo Mano
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
| | - Atsushi Iwata
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan.,Department of Neuropathology, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0015, Japan
| | - Shigeo Murayama
- Department of Neuropathology, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0015, Japan
| | - Toshiharu Suzuki
- Laboratory of Neuroscience, Graduate School of Pharmaceutical Sciences, Hokkaido University, Hokkaido 060-0812, Japan
| | - Takeshi Ikeuchi
- Department of Molecular Genetics, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Masaki Nishimura
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Shiga 520-2192, Japan
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6
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Ruiz-Riquelme A, Mao A, Barghash MM, Lau HHC, Stuart E, Kovacs GG, Nilsson KPR, Fraser PE, Schmitt-Ulms G, Watts JC. Aβ43 aggregates exhibit enhanced prion-like seeding activity in mice. Acta Neuropathol Commun 2021; 9:83. [PMID: 33971978 PMCID: PMC8112054 DOI: 10.1186/s40478-021-01187-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 04/24/2021] [Indexed: 02/07/2023] Open
Abstract
When injected into genetically modified mice, aggregates of the amyloid-β (Aβ) peptide from the brains of Alzheimer’s disease (AD) patients or transgenic AD mouse models seed cerebral Aβ deposition in a prion-like fashion. Within the brain, Aβ exists as a pool of distinct C-terminal variants with lengths ranging from 37 to 43 amino acids, yet the relative contribution of individual C-terminal Aβ variants to the seeding behavior of Aβ aggregates remains unknown. Here, we have investigated the relative seeding activities of Aβ aggregates composed exclusively of recombinant Aβ38, Aβ40, Aβ42, or Aβ43. Cerebral Aβ42 levels were not increased in AppNL−F knock-in mice injected with Aβ38 or Aβ40 aggregates and were only increased in a subset of mice injected with Aβ42 aggregates. In contrast, significant accumulation of Aβ42 was observed in the brains of all mice inoculated with Aβ43 aggregates, and the extent of Aβ42 induction was comparable to that in mice injected with brain-derived Aβ seeds. Mice inoculated with Aβ43 aggregates exhibited a distinct pattern of cerebral Aβ pathology compared to mice injected with brain-derived Aβ aggregates, suggesting that recombinant Aβ43 may polymerize into a unique strain. Our results indicate that aggregates containing longer Aβ C-terminal variants are more potent inducers of cerebral Aβ deposition and highlight the potential role of Aβ43 seeds as a crucial factor in the initial stages of Aβ pathology in AD.
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Trambauer J, Rodríguez Sarmiento RM, Fukumori A, Feederle R, Baumann K, Steiner H. Aβ43-producing PS1 FAD mutants cause altered substrate interactions and respond to γ-secretase modulation. EMBO Rep 2020; 21:e47996. [PMID: 31762188 PMCID: PMC6945062 DOI: 10.15252/embr.201947996] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 10/28/2019] [Accepted: 10/29/2019] [Indexed: 12/22/2022] Open
Abstract
Abnormal generation of neurotoxic amyloid-β peptide (Aβ) 42/43 species due to mutations in the catalytic presenilin 1 (PS1) subunit of γ-secretase is the major cause of familial Alzheimer's disease (FAD). Deeper mechanistic insight on the generation of Aβ43 is still lacking, and it is unclear whether γ-secretase modulators (GSMs) can reduce the levels of this Aβ species. By comparing several types of Aβ43-generating FAD mutants, we observe that very high levels of Aβ43 are often produced when presenilin function is severely impaired. Altered interactions of C99, the precursor of Aβ, are found for all mutants and are independent of their particular effect on Aβ production. Furthermore, unlike previously described GSMs, the novel compound RO7019009 can effectively lower Aβ43 production of all mutants. Finally, substrate-binding competition experiments suggest that RO7019009 acts mechanistically after initial C99 binding. We conclude that altered C99 interactions are a common feature of diverse types of PS1 FAD mutants and that also patients with Aβ43-generating FAD mutations could in principle be treated by GSMs.
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Affiliation(s)
- Johannes Trambauer
- Biomedical Center (BMC), Metabolic BiochemistryLudwig‐Maximilians‐UniversityMunichGermany
| | | | - Akio Fukumori
- Department of Aging NeurobiologyNational Center for Geriatrics and GerontologyObuJapan
- Department of Mental Health PromotionOsaka University Graduate School of MedicineToyonakaJapan
| | - Regina Feederle
- Institute for Diabetes and Obesity, Monoclonal Antibody Core Facility, Helmholtz Center MunichGerman Research Center for Environmental HealthNeuherbergGermany
- German Center for Neurodegenerative Diseases (DZNE)MunichGermany
| | - Karlheinz Baumann
- Roche Pharma Research and Early DevelopmentRoche Innovation Center Basel, F. Hoffmann‐La Roche Ltd.BaselSwitzerland
| | - Harald Steiner
- Biomedical Center (BMC), Metabolic BiochemistryLudwig‐Maximilians‐UniversityMunichGermany
- German Center for Neurodegenerative Diseases (DZNE)MunichGermany
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8
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Shen L, Qin W, Wu L, Zhou A, Tang Y, Wang Q, Jia L, Jia J. Two novel presenilin-1 mutations (I249L and P433S) in early onset Chinese Alzheimer's pedigrees and their functional characterization. Biochem Biophys Res Commun 2019; 516:264-269. [PMID: 31235249 DOI: 10.1016/j.bbrc.2019.05.185] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 05/30/2019] [Indexed: 01/02/2023]
Abstract
Clinical case study and functional characterization of the disease-associated presenilin-1 (PSEN1) mutations may help reveal the roles of PSEN1 in the pathogenesis of Alzheimer's disease (AD). By mutation screening of PSEN1, presenilin-2, and amyloid precursor protein genes in two Chinese Alzheimer's pedigrees, we identified two novel PSEN1 mutations, I249L and P433S. The two probands presented with progressive memory decline and subsequent psychiatric symptoms, with the age of onset at 54 and 34 years old, respectively. The effects of these two mutations on presenilin-1 endoproteolysis and β-amyloid (Aβ) production were examined in SH-SY5Y neuroblastoma cells infected with lentiviruses expressing presenilin-1 wild type (WT), I249L and P433S mutants. Both mutants showed increased Aβ42 levels and Aβ42/Aβ40 ratios. However, the I249L did not affect presenilin-1 endoproteolysis or Aβ43 production, whereas the P433S mutant inhibited presenilin-1 endoproteolysis and enhanced Aβ43 production. Our findings suggest that both I249L and P433S are pathogenic for early onset of AD by increasing Aβ42 production and Aβ42/Aβ40 ratios. Furthermore, P433S may contribute to the very early onset of AD by inhibiting PS1 endoproteolysis and enhancing the production of longer Aβ peptide Aβ43.
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Affiliation(s)
- Luxi Shen
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Wei Qin
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Liyong Wu
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Aihong Zhou
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Yi Tang
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Qi Wang
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Longfei Jia
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Jianping Jia
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China; Beijing Key Laboratory of Geriatric Cognitive Disorders, Beijing, 100053, PR China; Clinical Center for Neurodegenerative Disease and Memory Impairment, Capital Medical University, Beijing, 100053, PR China; Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing, 100053, PR China; Key Laboratory of Neurodegenerative Diseases, Ministry of Education, Beijing, 100053, PR China; National Clinical Research Center for Geriatric Disorders, Beijing, 100053, PR China.
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9
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Lessard CB, Rodriguez E, Ladd TB, Minter LM, Osborne BA, Miele L, Golde TE, Ran Y. Individual and combined presenilin 1 and 2 knockouts reveal that both have highly overlapping functions in HEK293T cells. J Biol Chem 2019; 294:11276-11285. [PMID: 31167792 DOI: 10.1074/jbc.ra119.008041] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 05/30/2019] [Indexed: 01/13/2023] Open
Abstract
Presenilins 1 and 2 (PS1 and 2) are the catalytic subunits of γ-secretase, a multiprotein protease that cleaves amyloid protein precursor and other type I transmembrane proteins. Previous studies with mouse models or cells have indicated differences in PS1 and PS2 functions. We have recently reported that clinical γ-secretase inhibitors (GSIs), initially developed to manage Alzheimer's disease and now being considered for other therapeutic interventions, are both pharmacologically and functionally distinct. Here, using CRISPR/Cas9-based gene editing, we established human HEK 293T cell lines in which endogenous PS1, PS2, or both have been knocked out. Using these knockout lines to examine differences in PS1- and PS2-mediated cleavage events, we confirmed that PS2 generates more intracellular β-amyloid than does PS1. Moreover, we observed subtle differences in PS1- and PS2-mediated cleavages of select substrates. In exploring the question of whether differences in activity among clinical GSIs could be attributed to differential inhibition of PS1 or PS2, we noted that select GSIs inhibit PS1 and PS2 activities on specific substrates with slightly different potencies. We also found that endoproteolysis of select PS1 FAD-linked variants in human cells is more efficient than what has been previously reported for mouse cell lines. Overall, these results obtained with HEK293T cells suggest that selective PS1 or PS2 inhibition by a given GSI does not explain the previously observed differences in functional and pharmacological properties among various GSIs.
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Affiliation(s)
- Christian B Lessard
- Department of Neuroscience and Neurology, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Edgardo Rodriguez
- Department of Pharmacology and Therapeutics, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, University of Florida, Gainesville, Florida 32610
| | - Thomas B Ladd
- Department of Neuroscience and Neurology, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Lisa M Minter
- Department of Veterinary and Animal Sciences, Center for Bioactive Delivery, Institute for Applied Life Sciences, and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Barbara A Osborne
- Department of Veterinary and Animal Sciences, Center for Bioactive Delivery, Institute for Applied Life Sciences, and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Lucio Miele
- Department of Genetics and Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
| | - Todd E Golde
- Department of Neuroscience and Neurology, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Yong Ran
- Department of Neuroscience and Neurology, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
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10
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Inoue K, Oliveira LMA, Abeliovich A. CRISPR Transcriptional Activation Analysis Unmasks an Occult γ-Secretase Processivity Defect in Familial Alzheimer's Disease Skin Fibroblasts. Cell Rep 2018; 21:1727-1736. [PMID: 29141208 DOI: 10.1016/j.celrep.2017.10.075] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 07/10/2017] [Accepted: 10/17/2017] [Indexed: 12/31/2022] Open
Abstract
Mutations in presenilin (PSEN) 1 and 2, which encode components of the γ-secretase (GS) complex, cause familial Alzheimer's disease (FAD). It is hypothesized that altered GS-mediated processing of the amyloid precursor protein (APP) to the Aβ42 fragment, which is accumulated in diseased brain, may be pathogenic. Here, we describe an in vitro model system that enables the facile analysis of neuronal disease mechanisms in non-neuronal patient cells using CRISPR gene activation of endogenous disease-relevant genes. In FAD patient-derived fibroblast cultures, CRISPR activation of APP or BACE unmasked an occult processivity defect in downstream GS-mediated carboxypeptidase cleavage of APP, ultimately leading to higher Aβ42 levels. These data suggest that, selectively in neurons, relatively high levels of BACE1 activity lead to substrate pressure on FAD-mutant GS complexes, promoting CNS Aβ42 accumulation. Our results introduce an additional platform for analysis of neurological disease.
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Affiliation(s)
- Keiichi Inoue
- Department of Pathology, Cell Biology and Neurology, Taub Institute, Columbia University Medical Center, 650 West 168th St., New York, NY 10032, USA.
| | - Luis M A Oliveira
- Department of Pathology, Cell Biology and Neurology, Taub Institute, Columbia University Medical Center, 650 West 168th St., New York, NY 10032, USA
| | - Asa Abeliovich
- Department of Pathology, Cell Biology and Neurology, Taub Institute, Columbia University Medical Center, 650 West 168th St., New York, NY 10032, USA.
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11
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Almdahl IS, Lauridsen C, Selnes P, Kalheim LF, Coello C, Gajdzik B, Møller I, Wettergreen M, Grambaite R, Bjørnerud A, Bråthen G, Sando SB, White LR, Fladby T. Cerebrospinal Fluid Levels of Amyloid Beta 1-43 Mirror 1-42 in Relation to Imaging Biomarkers of Alzheimer's Disease. Front Aging Neurosci 2017; 9:9. [PMID: 28223932 PMCID: PMC5293760 DOI: 10.3389/fnagi.2017.00009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 01/12/2017] [Indexed: 11/24/2022] Open
Abstract
Introduction: Amyloid beta 1-43 (Aβ43), with its additional C-terminal threonine residue, is hypothesized to play a role in early Alzheimer’s disease pathology possibly different from that of amyloid beta 1-42 (Aβ42). Cerebrospinal fluid (CSF) Aβ43 has been suggested as a potential novel biomarker for predicting conversion from mild cognitive impairment (MCI) to dementia in Alzheimer’s disease. However, the relationship between CSF Aβ43 and established imaging biomarkers of Alzheimer’s disease has never been assessed. Materials and Methods: In this observational study, CSF Aβ43 was measured with ELISA in 89 subjects; 34 with subjective cognitive decline (SCD), 51 with MCI, and four with resolution of previous cognitive complaints. All subjects underwent structural MRI; 40 subjects on a 3T and 50 on a 1.5T scanner. Forty subjects, including 24 with SCD and 12 with MCI, underwent 18F-Flutemetamol PET. Seventy-eight subjects were assessed with 18F-fluorodeoxyglucose PET (21 SCD/7 MCI and 11 SCD/39 MCI on two different scanners). Ten subjects with SCD and 39 with MCI also underwent diffusion tensor imaging. Results: Cerebrospinal fluid Aβ43 was both alone and together with p-tau a significant predictor of the distinction between SCD and MCI. There was a marked difference in CSF Aβ43 between subjects with 18F-Flutemetamol PET scans visually interpreted as negative (37 pg/ml, n = 27) and positive (15 pg/ml, n = 9), p < 0.001. Both CSF Aβ43 and Aβ42 were negatively correlated with standardized uptake value ratios for all analyzed regions; CSF Aβ43 average rho -0.73, Aβ42 -0.74. Both CSF Aβ peptides correlated significantly with hippocampal volume, inferior parietal and frontal cortical thickness and axial diffusivity in the corticospinal tract. There was a trend toward CSF Aβ42 being better correlated with cortical glucose metabolism. None of the studied correlations between CSF Aβ43/42 and imaging biomarkers were significantly different for the two Aβ peptides when controlling for multiple testing. Conclusion: Cerebrospinal fluid Aβ43 appears to be strongly correlated with cerebral amyloid deposits in the same way as Aβ42, even in non-demented patients with only subjective cognitive complaints. Regarding imaging biomarkers, there is no evidence from the present study that CSF Aβ43 performs better than the classical CSF biomarker Aβ42 for distinguishing SCD and MCI.
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Affiliation(s)
- Ina S Almdahl
- Division of Medicine and Laboratory Sciences, Institute of Clinical Medicine, Faculty of Medicine, University of OsloOslo, Norway; Department of Neurology, Akershus University HospitalLørenskog, Norway
| | - Camilla Lauridsen
- Department of Neuroscience, Faculty of Medicine, Norwegian University of Science and Technology Trondheim, Norway
| | - Per Selnes
- Division of Medicine and Laboratory Sciences, Institute of Clinical Medicine, Faculty of Medicine, University of OsloOslo, Norway; Department of Neurology, Akershus University HospitalLørenskog, Norway
| | - Lisa F Kalheim
- Division of Medicine and Laboratory Sciences, Institute of Clinical Medicine, Faculty of Medicine, University of OsloOslo, Norway; Department of Neurology, Akershus University HospitalLørenskog, Norway
| | - Christopher Coello
- Preclinical PET/CT, Institute of Basic Medical Sciences, University of Oslo Oslo, Norway
| | | | - Ina Møller
- Department of Neurology and Clinical Neurophysiology, University Hospital of Trondheim Trondheim, Norway
| | - Marianne Wettergreen
- Department of Neurology, Akershus University HospitalLørenskog, Norway; Department of Clinical Molecular Biology (EpiGen), Institute of Clinical Medicine, University of Oslo - Akershus University HospitalLørenskog, Norway
| | - Ramune Grambaite
- Department of Neurology, Akershus University Hospital Lørenskog, Norway
| | - Atle Bjørnerud
- The Intervention Centre, Oslo University Hospital Oslo, Norway
| | - Geir Bråthen
- Department of Neuroscience, Faculty of Medicine, Norwegian University of Science and TechnologyTrondheim, Norway; Department of Neurology and Clinical Neurophysiology, University Hospital of TrondheimTrondheim, Norway
| | - Sigrid B Sando
- Department of Neuroscience, Faculty of Medicine, Norwegian University of Science and TechnologyTrondheim, Norway; Department of Neurology and Clinical Neurophysiology, University Hospital of TrondheimTrondheim, Norway
| | - Linda R White
- Department of Neuroscience, Faculty of Medicine, Norwegian University of Science and TechnologyTrondheim, Norway; Department of Neurology and Clinical Neurophysiology, University Hospital of TrondheimTrondheim, Norway
| | - Tormod Fladby
- Division of Medicine and Laboratory Sciences, Institute of Clinical Medicine, Faculty of Medicine, University of OsloOslo, Norway; Department of Neurology, Akershus University HospitalLørenskog, Norway
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12
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Wang W, Moerman-Herzog AM, Slaton A, Barger SW. Presenilin 1 mutations influence processing and trafficking of the ApoE receptor apoER2. Neurobiol Aging 2016; 49:145-153. [PMID: 27810638 DOI: 10.1016/j.neurobiolaging.2016.10.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 09/29/2016] [Accepted: 10/01/2016] [Indexed: 12/15/2022]
Abstract
Presenilin (PS)-1 is an intramembrane protease serving as the catalytic component of γ-secretase. Mutations in the PS1 gene are the most common cause of familial Alzheimer's disease (FAD). The low-density lipoprotein (LDL)-receptor family member apoER2 is a γ-secretase substrate that has been associated with AD in several ways, including acting as a receptor for apolipoprotein E (ApoE). ApoER2 is processed by γ-secretase into a C-terminal fragment (γ-CTF) that appears to regulate gene expression. FAD PS1 mutations were tested for effects on apoER2. PS1 mutation R278I showed impaired γ-secretase activity for apoER2 in the basal state or after exposure to Reelin. PS1 M146V mutation permitted accumulation of apoER2 CTFs after Reelin treatment, whereas no difference was seen between wild-type (WT) and M146V in the basal state. PS1 L282V mutation, combined with the γ-secretase inhibitor N-(N-[3,5-Difluorophenacetyl]-L-alanyl)-S-phenylglycine t-butyl ester, greatly reduced the cell-surface levels of apoER2 without affecting total apoER2 levels, suggesting a defect in receptor trafficking. These findings indicate that impaired processing or localization of apoER2 may contribute to the pathogenic effects of FAD mutations in PS1.
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Affiliation(s)
- Wei Wang
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | | | - Arthur Slaton
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Steven W Barger
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA; Department of Neurobiology & Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA; Geriatrics Research, Education and Clinical Center, Central Arkansas Veterans Healthcare System, Little Rock, AR, USA.
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13
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Blain JF, Bursavich MG, Freeman EA, Hrdlicka LA, Hodgdon HE, Chen T, Costa DE, Harrison BA, Kapadnis S, Murphy DA, Nolan S, Tu Z, Tang C, Burnett DA, Patzke H, Koenig G. Characterization of FRM-36143 as a new γ-secretase modulator for the potential treatment of familial Alzheimer's disease. ALZHEIMERS RESEARCH & THERAPY 2016; 8:34. [PMID: 27572246 PMCID: PMC5004293 DOI: 10.1186/s13195-016-0199-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 07/18/2016] [Indexed: 01/01/2023]
Abstract
Background Familial Alzheimer’s disease (FAD) is caused by mutations in the amyloid precursor protein (APP) or presenilin (PS). Most PS mutations, which account for the majority of FAD cases, lead to an increased ratio of longer to shorter forms of the amyloid beta (Aβ) peptide. The therapeutic rationale of γ-secretase modulators (GSMs) for Alzheimer’s disease is based on this genetic evidence as well as on enzyme kinetics measurements showing changes in the processivity of the γ-secretase complex. This analysis suggests that GSMs could potentially offset some of the effects of PS mutations on APP processing, thereby addressing the root cause of early onset FAD. Unfortunately, the field has generated few, if any, molecules with good central nervous system (CNS) drug-like properties to enable proof-of-mechanism studies. Method We characterized the novel GSM FRM-36143 using multiple cellular assays to determine its in vitro potency and off-target activity as well as its potential to reverse the effect of PS mutations. We also tested its efficacy in vivo in wild-type mice and rats. Results FRM-36143 has much improved CNS drug-like properties compared to published GSMs. It has an in vitro EC50 for Aβ42 of 35 nM in H4 cells, can reduce Aβ42 to 58 % of the baseline in rat cerebrospinal fluid, and also increases the non-amyloidogenic peptides Aβ37 and Aβ38. It does not inhibit Notch processing, nor does it inhibit 24-dehydrocholesterol reductase (DHCR24) activity. Most interestingly, it can reverse the effects of presenilin mutations on APP processing in vitro. Conclusions FRM-36143 possesses all the characteristics of a GSM in terms of Aβ modulation Because FRM-36143 was able to reverse the effect of PS mutations, we suggest that targeting patients with this genetic defect would be the best approach at testing the efficacy of a GSM in the clinic. While the amyloid hypothesis is still being tested with β-site APP-cleaving enzyme inhibitors and monoclonal antibodies in sporadic AD, we believe it is not a hypothesis for FAD. Since GSMs can correct the molecular defect caused by PS mutations, they have the promise to provide benefits to the patients when treated early enough in the course of the disease.
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Affiliation(s)
| | | | - Emily A Freeman
- FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA
| | - Lori A Hrdlicka
- FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA
| | | | - Ting Chen
- FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA
| | - Don E Costa
- FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA
| | - Bryce A Harrison
- FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA
| | | | - Deirdre A Murphy
- FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA
| | - Scott Nolan
- FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA
| | - Zhiming Tu
- FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA
| | - Cuyue Tang
- FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA
| | - Duane A Burnett
- FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA
| | - Holger Patzke
- FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA
| | - Gerhard Koenig
- FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA
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14
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Liu L, Watanabe N, Akatsu H, Nishimura M. Neuronal expression of ILEI/FAM3C and its reduction in Alzheimer's disease. Neuroscience 2016; 330:236-46. [PMID: 27256505 DOI: 10.1016/j.neuroscience.2016.05.050] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 05/20/2016] [Accepted: 05/25/2016] [Indexed: 01/22/2023]
Abstract
Decrease in brain amyloid-β (Aβ) accumulation is a leading strategy for treating Alzheimer's disease (AD). However, the intrinsic mechanism of the regulation of brain Aβ production is largely unknown. Previously, we reported that ILEI (also referred to as FAM3C) binds to the γ-secretase complex and suppresses Aβ production without inhibiting γ-secretase activity. In this study, we examined ILEI expression in mouse brain using immunohistochemistry and subcellular fractionation. Brain ILEI showed widespread expression in neurons and ependymal cells but not in glial and vascular endothelial cells. Neuronal ILEI resided in perinuclear vesicular structures, which were positive for a marker protein of the trans-Golgi network. Although ILEI immunostaining was negative at synaptic terminals, synaptosome fractionation analysis suggested that ILEI was enriched in presynaptic terminals, particularly in the active zone-docked synaptic vesicles. ILEI expression levels in brain peaked during the postnatal period and declined with age. In comparison with age-matched control brains, the number of ILEI-immunoreactive neurons decreased in AD brains, although the subcellular localization was unaltered. Our results suggest that a decline of ILEI expression may cause accumulation of Aβ in the brain and the eventual development of AD.
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Affiliation(s)
- Lei Liu
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan
| | - Naoki Watanabe
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan
| | - Hiroyasu Akatsu
- Choju Medical Institute, Fukushimura Hospital, Toyohashi, Aichi 441-8124, Japan
| | - Masaki Nishimura
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan.
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15
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Kretner B, Trambauer J, Fukumori A, Mielke J, Kuhn PH, Kremmer E, Giese A, Lichtenthaler SF, Haass C, Arzberger T, Steiner H. Generation and deposition of Aβ43 by the virtually inactive presenilin-1 L435F mutant contradicts the presenilin loss-of-function hypothesis of Alzheimer's disease. EMBO Mol Med 2016; 8:458-65. [PMID: 26988102 PMCID: PMC5119496 DOI: 10.15252/emmm.201505952] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
As stated by the prevailing amyloid cascade hypothesis, Alzheimer's disease (AD) is caused by the aggregation and cerebral deposition of long amyloid‐β peptide (Aβ) species, which are released from a C‐terminal amyloid precursor protein fragment by γ‐secretase. Mutations in its catalytic subunit presenilin‐1 (PS1) increase the Aβ42 to Aβ40 ratio and are the major cause of familial AD (FAD). An opposing hypothesis states that loss of essential presenilin functions underlies the disease. A major argument for this hypothesis is the observation that the nearly inactive PS1 L435F mutant, paradoxically, causes FAD. We now show that the very little Aβ generated by PS1 L435F consists primarily of Aβ43, a highly amyloidogenic species which was overlooked in previous studies of this mutant. We further demonstrate that the generation of Aβ43 is not due to a trans‐dominant effect of this mutant on WT presenilin. Furthermore, we found Aβ43‐containing plaques in brains of patients with this mutation. The aberrant generation of Aβ43 by this particular mutant provides a direct objection against the presenilin hypothesis.
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Affiliation(s)
- Benedikt Kretner
- Biomedical Center, Metabolic Biochemistry, Ludwig-Maximilians-University Munich, Munich, Germany DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
| | - Johannes Trambauer
- Biomedical Center, Metabolic Biochemistry, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Akio Fukumori
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
| | - Janina Mielke
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Peer-Hendrik Kuhn
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany Neuroproteomics, Klinikum rechts der Isar and Institute for Advanced Study, Technische Universität München, Munich, Germany
| | - Elisabeth Kremmer
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany Institute of Molecular Immunology, Helmholtz Zentrum München, Munich, Germany
| | - Armin Giese
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Stefan F Lichtenthaler
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany Neuroproteomics, Klinikum rechts der Isar and Institute for Advanced Study, Technische Universität München, Munich, Germany Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Christian Haass
- Biomedical Center, Metabolic Biochemistry, Ludwig-Maximilians-University Munich, Munich, Germany DZNE - German Center for Neurodegenerative Diseases, Munich, Germany Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Thomas Arzberger
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany Center for Neuropathology and Prion Research, Ludwig-Maximilians-University Munich, Munich, Germany Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Harald Steiner
- Biomedical Center, Metabolic Biochemistry, Ludwig-Maximilians-University Munich, Munich, Germany DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
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16
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C-Terminal Threonine Reduces Aβ43 Amyloidogenicity Compared with Aβ42. J Mol Biol 2015; 428:274-291. [PMID: 26122432 DOI: 10.1016/j.jmb.2015.06.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Revised: 04/19/2015] [Accepted: 06/17/2015] [Indexed: 12/21/2022]
Abstract
Aβ43, a product of the proteolysis of the amyloid precursor protein APP, is related to Aβ42 by an additional Thr residue at the C-terminus. Aβ43 is typically generated at low levels compared with the predominant Aβ42 and Aβ40 forms, but it has been suggested that this longer peptide might have an impact on amyloid-β aggregation and Alzheimer's disease that is out of proportion to its brain content. Here, we report that both Aβ42 and Aβ43 spontaneously aggregate into mature amyloid fibrils via sequential appearance of the same series of oligomeric and protofibrillar intermediates, the earliest of which appears to lack β-structure. In spite of the additional β-branched amino acid at the C-terminus, Aβ43 fibrils have fewer strong backbone H-bonds than Aβ42 fibrils, some of which are lost at the C-terminus. In contrast to previous reports, we found that Aβ43 spontaneously aggregates more slowly than Aβ42. In addition, Aβ43 fibrils are very inefficient at seeding Aβ42 amyloid formation, even though Aβ42 fibrils efficiently seed amyloid formation by Aβ43 monomers. Finally, mixtures of Aβ42 and Aβ43 aggregate more slowly than Aβ42 alone. Both in this Aβ42/Aβ43 co-aggregation reaction and in cross-seeding by Aβ42 fibrils, the structure of the Aβ43 in the product fibrils is influenced by the presence of Aβ42. The results provide new details of amyloid structure and assembly pathways, an example of structural plasticity in prion-like replication, and data showing that low levels of Aβ43 in the brain are unlikely to favorably impact the aggregation of Aβ42.
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17
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Kretner B, Fukumori A, Kuhn PH, Pérez-Revuelta BI, Lichtenthaler SF, Haass C, Steiner H. Important functional role of residue x of the presenilin GxGD protease active site motif for APP substrate cleavage specificity and substrate selectivity of γ-secretase. J Neurochem 2013; 125:144-56. [PMID: 23237322 DOI: 10.1111/jnc.12124] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 12/10/2012] [Accepted: 12/10/2012] [Indexed: 11/30/2022]
Abstract
γ-Secretase plays a central role in the generation of the Alzheimer disease-causing amyloid β-peptide (Aβ) from the β-amyloid precursor protein (APP) and is thus a major Alzheimer's disease drug target. As several other γ-secretase substrates including Notch1 and CD44 have crucial signaling functions, an understanding of the mechanism of substrate recognition and cleavage is key for the development of APP selective γ-secretase-targeting drugs. The γ-secretase active site domain in its catalytic subunit presenilin (PS) 1 has been implicated in substrate recognition/docking and cleavage. Highly critical in this process is its GxGD active site motif, whose invariant glycine residues cannot be replaced without causing severe functional losses in substrate selection and/or cleavage efficiency. Here, we have investigated the contribution of the less well characterized residue x of the motif (L383 in PS1) to this function. Extensive mutational analysis showed that processing of APP was overall well-tolerated over a wide range of hydrophobic and hydrophilic mutations. Interestingly, however, most L383 mutants gave rise to reduced levels of Aβ37-39 species, and several increased the pathogenic Aβ42/43 species. Several of the Aβ42/43 -increasing mutants severely impaired the cleavages of Notch1 and CD44 substrates, which were not affected by any other L383 mutation. Our data thus establish an important, but compared with the glycine residues of the motif, overall less critical functional role for L383. We suggest that L383 and the flanking glycine residues form a spatial arrangement in PS1 that is critical for docking and/or cleavage of different γ-secretase substrates.
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Affiliation(s)
- Benedikt Kretner
- Adolf-Butenandt-Institute, Biochemistry, Ludwig-Maximilians-University, Munich, Germany
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18
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Sato N, Okochi M, Shinohara M, Thinakaran G, Takeda S, Fukumori A, Shinohara-Noma M, Mori-Ueda M, Hamada H, Takeda M, Rakugi H, Morishita R. Differential regulation of amyloid precursor protein/presenilin 1 interaction during Aβ40/42 [corrected] production detected using fusion constructs. PLoS One 2012; 7:e48551. [PMID: 23152781 PMCID: PMC3495957 DOI: 10.1371/journal.pone.0048551] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 09/26/2012] [Indexed: 12/12/2022] Open
Abstract
Beta amyloid peptides (Aβ) play a key role in the pathogenesis of Alzheimer disease (AD). Presenilins (PS) function as the catalytic subunits of γ-secretase, the enzyme that releases Aβ from ectodomain cleaved amyloid precursor protein (APP) by intramembrane proteolysis. Familial Alzheimer disease (FAD)-linked PSEN mutations alter APP processing in a manner that increases the relative abundance of longer Aβ42 peptides to that of Aβ40 peptides. The mechanisms by which Aβ40 and Aβ42 peptides are produced in a ratio of ten to one by wild type presenilin (PS) and by which Aβ42 is overproduced by FAD-linked PS variants are not completely understood. We generated chimeras of the amyloid precursor protein C-terminal fragment (C99) and PS to address this issue. We found a chimeric protein where C99 is fused to the PS1 N-terminus undergoes in cis processing to produce Aβ and that a fusion protein harboring FAD-linked PS1 mutations overproduced Aβ42. To change the molecular interactions within the C99-PS1 fusion protein, we made sequential deletions of the junction between C99 and PS1. We found differential effects of deletion in C99-PS1 on Aβ40 and 42 production. Deletion of the junction between APP CTF and PS1 in the fusion protein decreased Aβ40, while it did not decrease Aβ42 production in the presence or absence of FAD-linked PS1 mutation. These results are consistent with the idea that the APP/PS interaction is differentially regulated during Aβ40 and 42 production.
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Affiliation(s)
- Naoyuki Sato
- Department of Clinical Gene Therapy, Graduate School of Medicine, Osaka University, Yamada-oka, Suita, Japan.
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19
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Kakuda N, Shoji M, Arai H, Furukawa K, Ikeuchi T, Akazawa K, Takami M, Hatsuta H, Murayama S, Hashimoto Y, Miyajima M, Arai H, Nagashima Y, Yamaguchi H, Kuwano R, Nagaike K, Ihara Y. Altered γ-secretase activity in mild cognitive impairment and Alzheimer's disease. EMBO Mol Med 2012; 4:344-52. [PMID: 22354516 PMCID: PMC3376855 DOI: 10.1002/emmm.201200214] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 12/22/2011] [Accepted: 01/09/2012] [Indexed: 02/02/2023] Open
Abstract
We investigated why the cerebrospinal fluid (CSF) concentrations of Aβ42 are lower in mild cognitive impairment (MCI) and Alzheimer's disease (AD) patients. Because Aβ38/42 and Aβ40/43 are distinct product/precursor pairs, these four species in the CSF together should faithfully reflect the status of brain γ-secretase activity, and were quantified by specific enzyme-linked immunosorbent assays in the CSF from controls and MCI/AD patients. Decreases in the levels of the precursors, Aβ42 and 43, in MCI/AD CSF tended to accompany increases in the levels of the products, Aβ38 and 40, respectively. The ratios Aβ40/43 versus Aβ38/42 in CSF (each representing cleavage efficiency of Aβ43 or Aβ42) were largely proportional to each other but generally higher in MCI/AD patients compared to control subjects. These data suggest that γ-secretase activity in MCI/AD patients is enhanced at the conversion of Aβ43 and 42 to Aβ40 and 38, respectively. Consequently, we measured the in vitro activity of raft-associated γ-secretase isolated from control as well as MCI/AD brains and found the same, significant alterations in the γ-secretase activity in MCI/AD brains.
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20
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Saito T, Suemoto T, Brouwers N, Sleegers K, Funamoto S, Mihira N, Matsuba Y, Yamada K, Nilsson P, Takano J, Nishimura M, Iwata N, Van Broeckhoven C, Ihara Y, Saido TC. Potent amyloidogenicity and pathogenicity of Aβ43. Nat Neurosci 2011; 14:1023-32. [PMID: 21725313 DOI: 10.1038/nn.2858] [Citation(s) in RCA: 215] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 05/13/2011] [Indexed: 11/09/2022]
Abstract
The amyloid-β peptide Aβ42 is known to be a primary amyloidogenic and pathogenic agent in Alzheimer's disease. However, the role of Aβ43, which is found just as frequently in the brains of affected individuals, remains unresolved. We generated knock-in mice containing a pathogenic presenilin-1 R278I mutation that causes overproduction of Aβ43. Homozygosity was embryonic lethal, indicating that the mutation involves a loss of function. Crossing amyloid precursor protein transgenic mice with heterozygous mutant mice resulted in elevated Aβ43, impairment of short-term memory and acceleration of amyloid-β pathology, which accompanied pronounced accumulation of Aβ43 in plaque cores similar in biochemical composition to those observed in the brains of affected individuals. Consistently, Aβ43 showed a higher propensity to aggregate and was more neurotoxic than Aβ42. Other pathogenic presenilin mutations also caused overproduction of Aβ43 in a manner correlating with Aβ42 and with the age of disease onset. These findings indicate that Aβ43, an overlooked species, is potently amyloidogenic, neurotoxic and abundant in vivo.
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Affiliation(s)
- Takashi Saito
- Laboratory for Proteolytic Neuroscience, RIKEN Brain Science Institute, Wako-shi, Saitama, Japan
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21
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Kretner B, Fukumori A, Gutsmiedl A, Page RM, Luebbers T, Galley G, Baumann K, Haass C, Steiner H. Attenuated Abeta42 responses to low potency gamma-secretase modulators can be overcome for many pathogenic presenilin mutants by second-generation compounds. J Biol Chem 2011; 286:15240-51. [PMID: 21357415 DOI: 10.1074/jbc.m110.213587] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Sequential processing of the β-amyloid precursor protein by β- and γ-secretase generates the amyloid β-peptide (Aβ), which is widely believed to play a causative role in Alzheimer disease. Selective lowering of the pathogenic 42-amino acid variant of Aβ by γ-secretase modulators (GSMs) is a promising therapeutic strategy. Here we report that mutations in presenilin (PS), the catalytic subunit of γ-secretase, display differential responses to non-steroidal anti-inflammatory drug (NSAID)-type GSMs and more potent second-generation compounds. Although many pathogenic PS mutations resisted lowering of Aβ(42) generation by the NSAID sulindac sulfide, the potent NSAID-like second-generation compound GSM-1 was capable of lowering Aβ(42) for many but not all mutants. We further found that mutations at homologous positions in PS1 and PS2 can elicit differential Aβ(42) responses to GSM-1, suggesting that a positive GSM-1 response depends on the spatial environment in γ-secretase. The aggressive pathogenic PS1 L166P mutation was one of the few pathogenic mutations that resisted GSM-1, and Leu-166 was identified as a critical residue with respect to the Aβ(42)-lowering response of GSM-1. Finally, we found that GSM-1-responsive and -resistant PS mutants behave very similarly toward other potent second-generation compounds of different structural classes than GSM-1. Taken together, our data show that a positive Aβ(42) response for PS mutants depends both on the particular mutation and the GSM used and that attenuated Aβ(42) responses to low potency GSMs can be overcome for many PS mutants by second generation GSMs.
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Affiliation(s)
- Benedikt Kretner
- DZNE-German Center for Neurodegenerative Diseases, Ludwig-Maximilians-University, 80336 Munich, Germany
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Hasegawa H, Liu L, Nishimura M. Dilysine retrieval signal-containing p24 proteins collaborate in inhibiting γ-cleavage of amyloid precursor protein. J Neurochem 2010; 115:771-81. [PMID: 20807314 DOI: 10.1111/j.1471-4159.2010.06977.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
γ-Secretase mediates intramembranous γ-cleavage and ε-cleavage of β-amyloid precursor protein (APP) to liberate β-amyloid peptide (Aβ) and APP intracellular domain respectively from the membrane. Although the regulatory mechanism of γ-secretase cleavage remains unresolved, a member of the p24 cargo protein family, named p24δ(1) or TMP21, has been identified as an activity-modulating component. The p24 family proteins are divided into four subfamilies (p24α, β, δ and γ). In contrast to p24δ(1), p24β(1) has reportedly no effect on γ-cleavage. In this study, we determined whether p24α(2), p24γ(3) or p24γ(4) modulates APP processing. Knockdown of cellular p24α(2) induced a significant increase in Aβ generation but not in APP intracellular domain production in cell-based and cell-free assays, whereas p24α(2) over-expression suppressed Aβ secretion. By contrast, Aβ secretion was not altered by p24γ(3) or p24γ(4) knockdown. Endogenous p24α(2) co-immunoprecipitated with core components of the γ-secretase complex, and the anti-p24α(2) immunoprecipitate exhibited γ-secretase activity. Mutational disruption of the conserved dilysine ER-retrieval motifs of p24α(2) and p24δ(1) perturbed inhibition of γ-cleavage. Simultaneous knockdown, or co-over-expression, of these proteins had no additive or synergistic effect on Aβ generation. Our findings suggest that dilysine ER-retrieval signal-containing p24 proteins, p24α(2) and p24δ(1), bind with γ-secretase complexes and collaborate in attenuating γ-cleavage of APP.
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Affiliation(s)
- Hiroshi Hasegawa
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu, Shiga, Japan.
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Three-amino acid spacing of presenilin endoproteolysis suggests a general stepwise cleavage of gamma-secretase-mediated intramembrane proteolysis. J Neurosci 2010; 30:7853-62. [PMID: 20534834 DOI: 10.1523/jneurosci.1443-10.2010] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Presenilin (PS1 or PS2) is the catalytic component of the gamma-secretase complex, which mediates the final proteolytic processing step leading to the Alzheimer's disease (AD)-characterizing amyloid beta-peptide. PS is cleaved during complex assembly into its characteristic N- and C-terminal fragments. Both fragments are integral components of physiologically active gamma-secretase and harbor the two critical aspartyl residues of the active site domain. While the minimal subunit composition of gamma-secretase has been defined and numerous substrates were identified, the cellular mechanism of the endoproteolytic cleavage of PS is still unclear. We addressed this pivotal question by investigating whether familial AD (FAD)-associated PS1 mutations affect the precision of PS endoproteolysis in a manner similar to the way that such mutations shift the intramembrane cleavage of gamma-secretase substrates. We demonstrate that all FAD mutations investigated still allow endoproteolysis to occur. However, the precision of PS1 endoproteolysis is affected by PS1 mutations. Comparing the cleavage products generated by a variety of PS1 mutants revealed that specifically cleavages at positions 293 and 296 of PS1 are selectively affected. Systematic mutagenesis around the cleavage sites revealed a stepwise three amino acid spaced cleavage mechanism of PS endoproteolysis reminiscent to the epsilon-, zeta-, and gamma-cleavages described for typical gamma-secretase substrates, such as the beta-amyloid precursor protein. Our findings therefore suggest that intramembranous cleavage by gamma-secretase and related intramembrane-cleaving proteases may generally occur via stepwise endoproteolysis.
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Heilig EA, Xia W, Shen J, Kelleher RJ. A presenilin-1 mutation identified in familial Alzheimer disease with cotton wool plaques causes a nearly complete loss of gamma-secretase activity. J Biol Chem 2010; 285:22350-9. [PMID: 20460383 DOI: 10.1074/jbc.m110.116962] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in presenilin-1 and presenilin-2 (PS1 and PS2) are the most common cause of familial Alzheimer disease. PS1 and PS2 are the presumptive catalytic components of the multisubunit gamma-secretase complex, which proteolyzes a number of type I transmembrane proteins, including the amyloid precursor protein (APP) and Notch. APP processing by gamma-secretase produces beta-amyloid peptides (Abeta40 and Abeta42) that accumulate in the Alzheimer disease brain. Here we identify a pathogenic L435F mutation in PS1 in two affected siblings with early-onset familial Alzheimer disease characterized by deposition of cerebral cotton wool plaques. The L435F mutation resides in a conserved C-terminal PAL sequence implicated in active site conformation and catalytic activity. The impact of PS1 mutations in and around the PAL motif on gamma-secretase activity was assessed by expression of mutant PS1 in mouse embryo fibroblasts lacking endogenous PS1 and PS2. Surprisingly, the L435F mutation caused a nearly complete loss of gamma-secretase activity, including >90% reductions in the generation of Abeta40, Abeta42, and the APP and Notch intracellular domains. Two nonpathogenic PS1 mutations, P433L and L435R, caused essentially complete loss of gamma-secretase activity, whereas two previously identified pathogenic PS1 mutations, P436Q and P436S, caused partial loss of function with substantial reductions in production of Abeta40, Abeta42, and the APP and Notch intracellular domains. These results argue against overproduction of Abeta42 as an essential property of presenilin proteins bearing pathogenic mutations. Rather, our findings provide support for the hypothesis that pathogenic mutations cause a general loss of presenilin function.
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Affiliation(s)
- Elizabeth A Heilig
- Center for Human Genetic Research and Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
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25
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Mitsuishi Y, Hasegawa H, Matsuo A, Araki W, Suzuki T, Tagami S, Okochi M, Takeda M, Roepman R, Nishimura M. Human CRB2 inhibits gamma-secretase cleavage of amyloid precursor protein by binding to the presenilin complex. J Biol Chem 2010; 285:14920-14931. [PMID: 20299451 DOI: 10.1074/jbc.m109.038760] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Drosophila Crumbs has been reported to attenuate Notch signaling by inhibition of gamma-secretase cleavage at the wing margins. gamma-Secretase is an intramembrane protease that is responsible for the generation of amyloid-beta (Abeta) peptides from the beta-amyloid precursor protein (APP). Here, we re-examined gamma-secretase inhibition by human CRB2, which is the most abundant Crumbs ortholog in the brain. Transfected CRB2 inhibited proteolytic production of Abeta and APP intracellular domains from APP C-terminal fragments in HEK293 and SH-SY5Y cells. Conversely, knockdown of endogenous CRB2 increased gamma-secretase cleavage products in SH-SY5Y cells. CRB2 inhibition of gamma-cleavage was also detected in cell-free assays. CRB2 interacted with the gamma-secretase complex, but was not a competitive substrate for gamma-cleavage. The transmembrane domain of CRB2 was indispensable for inhibition of Abeta generation and mediated CRB2 binding with the gamma-secretase complex. In addition, the cytoplasmic domain appeared to play a supportive role in gamma-secretase inhibition, whereas mutational disruption of the two protein-binding motifs involved in the formation of cell adhesion complexes did not affect gamma-secretase inhibition. Co-overexpression of presenilin-1 or APH-1 abrogated gamma-secretase inhibition probably through prevention of the incorporation of CRB2 into the gamma-secretase complex. Our results suggest that CRB2 functions as an inhibitory binding protein that is involved in the formation of a mature but inactive pool of the gamma-secretase complex.
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Affiliation(s)
- Yachiyo Mitsuishi
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Shiga 520-2192, Japan
| | - Hiroshi Hasegawa
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Shiga 520-2192, Japan
| | - Akinori Matsuo
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Shiga 520-2192, Japan
| | - Wataru Araki
- Department of Demyelinating Disease and Aging, National Institute of Neuroscience, NCNP, Tokyo 187-8502, Japan
| | - Toshiharu Suzuki
- Laboratory of Neuroscience, Graduate School of Pharmaceutical Sciences, Hokkaido University, Hokkaido 060-0812, Japan
| | - Shinji Tagami
- Department of Post-Genomics and Diseases, Division of Psychiatry and Behavioral Proteomics, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Masayasu Okochi
- Department of Post-Genomics and Diseases, Division of Psychiatry and Behavioral Proteomics, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Masatoshi Takeda
- Department of Post-Genomics and Diseases, Division of Psychiatry and Behavioral Proteomics, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Ronald Roepman
- Department of Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen 6500 HB, The Netherlands
| | - Masaki Nishimura
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Shiga 520-2192, Japan.
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Pérez-Revuelta BI, Fukumori A, Lammich S, Yamasaki A, Haass C, Steiner H. Requirement for small side chain residues within the GxGD-motif of presenilin for gamma-secretase substrate cleavage. J Neurochem 2009; 112:940-50. [PMID: 20021564 DOI: 10.1111/j.1471-4159.2009.06510.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
gamma-Secretase is a pivotal intramembrane-cleaving protease complex and important drug target for Alzheimer's disease. The protease not only releases small peptides, such as the amyloid-beta peptide, which drives Alzheimer's disease pathogenesis, but also intracellular domains, which can have critical functions in nuclear signaling. Unlike typical aspartyl proteases, gamma-secretase contains a non-classical GxGD active site motif in its catalytic subunit presenilin (PS) 1 or PS2. It is not known whether both glycines are of similar functional relevance and why the glycine residues are invariant elements of the motif. Here we identify the N-terminal glycine of the GxGD motif in PS1, G382, as a critical residue of the active site domain of gamma-secretase. Substitution of G382 by a number of different amino acids abrogated gamma-secretase activity. Only the smallest possible G382A substitution allowed substantial gamma-secretase activity. Depending on the substrate, however, the presence of G382 could become even an absolute functional requirement of gamma-secretase. Very similar results were obtained for the C-terminal glycine residue (G384) of the GxGD motif. Our data thus identify a requirement for small side chain residues in the active site domain of gamma-secretase and suggest that the glycines of the GxGD motif could be evolutionary conserved to allow cleavage of all possible gamma-secretase substrates, including those, which are highly sensitive to minimal alteration of the PS active site domain. These findings broaden our understanding of gamma-secretase substrate recognition and cleavage, which may prove crucial for therapeutic targeting of the enzyme.
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Affiliation(s)
- Blanca Isabel Pérez-Revuelta
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE) and Adolf-Butenandt-Institute, Biochemistry, Ludwig-Maximilians-University, München, Germany
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Marks N, Berg MJ. BACE and gamma-secretase characterization and their sorting as therapeutic targets to reduce amyloidogenesis. Neurochem Res 2009; 35:181-210. [PMID: 19760173 DOI: 10.1007/s11064-009-0054-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Accepted: 08/21/2009] [Indexed: 10/20/2022]
Abstract
Secretases are named for enzymes processing amyloid precursor protein (APP), a prototypic type-1 membrane protein. This led directly to discovery of novel Aspartyl proteases (beta-secretases or BACE), a tetramer complex gamma-secretase (gamma-SC) containing presenilins, nicastrin, aph-1 and pen-2, and a new role for metalloprotease(s) of the ADAM family as a alpha-secretases. Recent advances in defining pathways that mediate endosomal-lysosomal-autophagic-exosomal trafficking now provide targets for new drugs to attenuate abnormal production of fibril forming products characteristic of AD. A key to success includes not only characterization of relevant secretases but mechanisms for sorting and transport of key metabolites to abnormal vesicles or sites for assembly of fibrils. New developments we highlight include an important role for an 'early recycling endosome' coated in retromer complex containing lipoprotein receptor LRP-II (SorLA) for switching APP to a non-amyloidogenic pathway for alpha-secretases processing, or to shuttle APP to a 'late endosome compartment' to form Abeta or AICD. LRP11 (SorLA) is of particular importance since it decreases in sporadic AD whose etiology otherwise is unknown.
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Affiliation(s)
- Neville Marks
- Center for Neurochemistry, Nathan S Kline Institute for Psychiatric Research, 140 Old Orangeburg Road, Orangeburg, NY 10962, USA.
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28
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Kim SD, Kim J. Sequence analyses of presenilin mutations linked to familial Alzheimer's disease. Cell Stress Chaperones 2008; 13:401-12. [PMID: 18491041 PMCID: PMC2673935 DOI: 10.1007/s12192-008-0046-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Revised: 04/07/2008] [Accepted: 04/09/2008] [Indexed: 12/26/2022] Open
Abstract
Familial Alzheimer's disease (FAD)-linked presenilin (PS) mutations show gain-of-toxic-function characteristics. These FAD PS mutations are scattered throughout the PS molecule, reminiscent of the distribution of cystic fibrosis transmembrane conductance regulator and p53 mutations. Because of the scattered distribution of PS mutations, it is difficult to infer mechanistic insights about how these mutations cause the disease similarly. Recent careful reexamination of gamma-secretase activity indicates that some PS mutations decrease the proteolytic activity of gamma-secretase, suggesting a loss-of-function nature of PS mutations. To extend this observation to all known PS mutations, a large number of PS mutations were evaluated using bioinformatic tools. The analyses reveal that as many as one third of PS1 residues are highly conserved, that about 75% of FAD mutations are located to the highly conserved residues, and that most PS mutations likely damage the activity of PS. These results are consistent with the idea that the majority of PS mutations lower the activity of PS/gamma-secretase.
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Affiliation(s)
- Sun Don Kim
- Section of Genetics, Department of Pediatrics, M.I.N.D. Institute, University of California – Davis Medical Center, Sacramento, CA 95817 USA
| | - Jinoh Kim
- Section of Genetics, Department of Pediatrics, M.I.N.D. Institute, University of California – Davis Medical Center, Sacramento, CA 95817 USA
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29
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The C-terminal PAL motif and transmembrane domain 9 of presenilin 1 are involved in the formation of the catalytic pore of the gamma-secretase. J Neurosci 2008; 28:6264-71. [PMID: 18550769 DOI: 10.1523/jneurosci.1163-08.2008] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Gamma-secretase is an unusual membrane-embedded protease, which cleaves the transmembrane domains (TMDs) of type I membrane proteins, including amyloid-beta precursor protein and Notch receptor. We have previously shown the existence of a hydrophilic pore formed by TMD6 and TMD7 of presenilin 1 (PS1), the catalytic subunit of gamma-secretase, within the membrane by the substituted cysteine accessibility method. Here we analyzed the structure of TMD8, TMD9, and the C terminus of PS1, which encompass the conserved PAL motif and the hydrophobic C-terminal tip, both being critical for the catalytic activity and the formation of the gamma-secretase complex. We found that the amino acid residues around the PAL motif and the extracellular/luminal portion of TMD9 are highly water accessible and located in proximity to the catalytic pore. Furthermore, the region starting from the luminal end of TMD9 toward the C terminus forms an amphipathic alpha-helix-like structure that extends along the interface between the membrane and the extracellular milieu. Competition analysis using gamma-secretase inhibitors revealed that the TMD9 is involved in the initial binding of substrates, as well as in the subsequent catalytic process as a subsite. Our results provide mechanistic insights into the role of TMD9 in the formation of the catalytic pore and the substrate entry, crucial to the unusual mode of intramembrane proteolysis by gamma-secretase.
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30
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Zhao B, Yu M, Neitzel M, Marugg J, Jagodzinski J, Lee M, Hu K, Schenk D, Yednock T, Basi G. Identification of γ-Secretase Inhibitor Potency Determinants on Presenilin. J Biol Chem 2008; 283:2927-38. [DOI: 10.1074/jbc.m708870200] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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31
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Marks N, Berg MJ. Neurosecretases provide strategies to treat sporadic and familial Alzheimer disorders. Neurochem Int 2008; 52:184-215. [PMID: 17719698 DOI: 10.1016/j.neuint.2007.06.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Revised: 06/05/2007] [Indexed: 12/30/2022]
Abstract
Recent discoveries on neurosecretases and their trafficking to release fibril-forming neuropeptides or other products, are of interest to pathology, cell signaling and drug discovery. Nomenclature arose from the use of amyloid precursor protein (APP) as a prototypic type-1 substrate leading to the isolation of beta-secretase (BACE), multimeric complexes (gamma-secretase, gamma-SC) for intramembranal cleavage, and attributing a new function to well-characterized metalloproteases of the ADAM family (alpha-secretase) for normal APP turnover. While purified alpha/beta-secretases facilitate drug discovery, gamma-SC presents greater challenges for characterization and mechanisms of catalysis. The review comments on links between mutation or polymorphisms in relation to enzyme mechanisms and disease. The association between lipoprotein receptor LRP11 variants and sporadic Alzheimer's disease (SAD) offers scope to integrate components of pre- and post-Golgi membranes, or brain clathrin-coated vesicles within pathways for trafficking as targets for intervention. The presence of APP and metabolites in brain clathrin-coated vesicles as significant cargo with lipoproteins and adaptors focuses attention as targets for therapeutic intervention. This overview emphasizes the importance to develop new therapies targeting neurosecretases to treat a major neurological disorder that has vast economic and social implications.
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Affiliation(s)
- Neville Marks
- Center for Neurochemistry, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, United States.
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32
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Regulation of Notch signaling by dynamic changes in the precision of S3 cleavage of Notch-1. Mol Cell Biol 2007; 28:165-76. [PMID: 17967888 DOI: 10.1128/mcb.00863-07] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Intramembrane proteolysis by presenilin-dependent gamma-secretase produces the Notch intracellular cytoplasmic domain (NCID) and Alzheimer disease-associated amyloid-beta. Here, we show that upon Notch signaling the intracellular domain of Notch-1 is cleaved into two distinct types of NICD species due to diversity in the site of S3 cleavage. Consistent with the N-end rule, the S3-V cleavage produces stable NICD with Val at the N terminus, whereas the S3-S/S3-L cleavage generates unstable NICD with Ser/Leu at the N terminus. Moreover, intracellular Notch signal transmission with unstable NICDs is much weaker than that with stable NICD. Importantly, the extent of endocytosis in target cells affects the relative production ratio of the two types of NICD, which changes in parallel with Notch signaling. Surprisingly, substantial amounts of unstable NICD species are generated from the Val-->Gly and the Lys-->Arg mutants, which have been reported to decrease S3 cleavage efficiency in cultured cells. Thus, we suggest that the existence of two distinct types of NICD points to a novel aspect of the intracellular signaling and that changes in the precision of S3 cleavage play an important role in the process of conversion from extracellular to intracellular Notch signaling.
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Sato T, Diehl TS, Narayanan S, Funamoto S, Ihara Y, De Strooper B, Steiner H, Haass C, Wolfe MS. Active gamma-secretase complexes contain only one of each component. J Biol Chem 2007; 282:33985-93. [PMID: 17911105 DOI: 10.1074/jbc.m705248200] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gamma-secretase is an intramembrane aspartyl protease complex that cleaves type I integral membrane proteins, including the amyloid beta-protein precursor and the Notch receptor, and is composed of presenilin, Pen-2, nicastrin, and Aph-1. Although all four of these membrane proteins are essential for assembly and activity, the stoichiometry of the complex is unknown, with the number of presenilin molecules present being especially controversial. Here we analyze functional gamma-secretase complexes, isolated by immunoprecipitation from solubilized membrane fractions and able to produce amyloid beta-peptides and amyloid beta-protein precursor intracellular domain. We show that the active isolated protease contains only one presenilin per complex, which excludes certain models of the active site that require aspartate dyads formed between two presenilin molecules. We also quantified components in the isolated complexes by Western blot using protein standards and found that the amounts of Pen-2 and nicastrin were the same as that of presenilin. Moreover, we found that one Aph-1 was not co-immunoprecipitated with another in active complexes, evidence that Aph-1 is likewise present as a monomer. Taken together, these results demonstrate that the stoichiometry of gamma-components presenilin:Pen-2:nicastrin:Aph-1 is 1:1:1:1.
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Affiliation(s)
- Toru Sato
- Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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34
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Zhou XW, Li X, Bjorkdahl C, Sjogren MJ, Alafuzoff I, Soininen H, Grundke-Iqbal I, Iqbal K, Winblad B, Pei JJ. Assessments of the accumulation severities of amyloid β-protein and hyperphosphorylated tau in the medial temporal cortex of control and Alzheimer's brains. Neurobiol Dis 2006; 22:657-68. [PMID: 16513361 DOI: 10.1016/j.nbd.2006.01.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2005] [Revised: 01/05/2006] [Accepted: 01/15/2006] [Indexed: 11/23/2022] Open
Abstract
Alzheimer's disease (AD) is characterized neuropathologically by neuritic plaques (NPs), and neurofibrillary tangles (NFTs). So far, the following key issues are not yet answered to the disease: (1) the accumulation degrees of three Abeta variants, and tau phosphorylation epitopes in AD as compared to control; (2) the correlation degrees of levels of three Abeta variants with different tau phosphorylation epitopes; (3) the correlation degrees of levels of three Abeta variants and different tau phosphorylation epitopes with Braak and CERAD staging systems. To address these issues, levels of Abeta40, Abeta42, and Abeta43, and phosphorylated tau were assessed by dot blots in homogenates of the medial temporal cortex from AD and control brains in the present study. These data implied different roles of tau phosphorylation epitopes in formation of NFTs, and in this process, Abeta might play a key role. Assessments of levels of these abnormal proteins by dot blots may serve as a useful complement to the morphological evaluations in diagnosis of AD.
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Affiliation(s)
- Xin-Wen Zhou
- Karolinska Institutet, Department of Neurotec, Geriatric-lab, Novum Plan 5, S-14157, Huddinge, Sweden
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35
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Wang J, Beher D, Nyborg AC, Shearman MS, Golde TE, Goate A. C-terminal PAL motif of presenilin and presenilin homologues required for normal active site conformation. J Neurochem 2006; 96:218-27. [PMID: 16305624 DOI: 10.1111/j.1471-4159.2005.03548.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The Alzheimer's disease-associated beta-amyloid peptide is produced through cleavage of amyloid precursor protein by beta-secretase and gamma-secretase. gamma-Secretase is a complex containing presenilin (PS) as the catalytic component and three essential cofactors: Nicastrin, anterior pharynx defective (APH-1) and presenilin enhancer-2 (PEN-2). PS and signal peptide peptidase (SPP) define a novel family of aspartyl proteases that cleave substrates within the transmembrane domain presumptively using two membrane-embedded aspartic acid residues for catalysis. Apart from the two aspartate-containing active site motifs, the only other region that is conserved between PS and SPP is a PAL sequence at the C-terminus. Although it has been well documented that this motif is essential for gamma-secretase activity, the mechanism underlying such a critical role is not understood. Here we show that mutations in this motif affect the conformation of the active site of gamma-secretase resulting in a complete loss of PS binding to a gamma-secretase transition state analog inhibitor, Merck C. Analogous mutations in SPP significantly inhibit its enzymatic activity. Furthermore, these mutations also abolish SPP binding to Merck C, indicating that SPP and gamma-secretase share a similar active site conformation, which is dependent on the PAL motif. Exploring the amino acid requirements within this motif reveals a very small side chain requirement, which is conserved during evolution. Together, these observations strongly support the hypothesis that the PAL motif contributes to the active site conformation of gamma-secretase and of SPP.
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Affiliation(s)
- Jun Wang
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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36
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Bizimungu C, Vandenbol M. At least two regions of the oncoprotein Tre2 are involved in its lack of GAP activity. Biochem Biophys Res Commun 2005; 335:883-90. [PMID: 16099424 DOI: 10.1016/j.bbrc.2005.07.159] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2005] [Accepted: 07/29/2005] [Indexed: 11/30/2022]
Abstract
The product of the human Tre2 oncogene is structurally related to the Ypt/Rab GTPase-activating proteins (Ypt/Rab GAPs). Particularly, the oncoprotein shares with the yeast proteins Msb3p and Msb4p, and with the human protein RN-tre the highly conserved TBC domain, forming the catalytically active domain of Ypt/Rab GAPs. Yet, the Tre2 oncogene seems to encode a nonfunctional Rab GAP. As regions flanking the TBC domain may be crucial for catalytic activity, regions located N- and C-terminally with respect to this domain were explored. For this, chimeric proteins created by sequence exchanges between the Tre2 oncoprotein and RN-tre were tested for their ability to replace functionally the Msb3p and Msb4p proteins in double-mutant yeast cells. These complementation experiments revealed, in addition to the TBC domain, a second Tre2 region involved in the oncoprotein's lack of GAP activity: a 93-aa region flanking the TBC domain on the C-terminal side.
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Affiliation(s)
- Christelle Bizimungu
- Animal and Microbial Biology Unit, Gembloux Agricultural University, B-5030 Gembloux, Belgium.
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