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Tsintzas E, Niccoli T. Using Drosophila amyloid toxicity models to study Alzheimer's disease. Ann Hum Genet 2024; 88:349-363. [PMID: 38517001 DOI: 10.1111/ahg.12554] [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: 10/11/2023] [Revised: 01/28/2024] [Accepted: 01/29/2024] [Indexed: 03/23/2024]
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia and is characterised by a progressive loss of neurons, which manifests as gradual memory decline, followed by cognitive loss. Despite the significant progress in identifying novel biomarkers and understanding the prodromal pathology and symptomatology, AD remains a significant unmet clinical need. Lecanemab and aducanumab, the only Food and Drug Administration approved drugs to exhibit some disease-modifying clinical efficacy, target Aβ amyloid, underscoring the importance of this protein in disease aetiology. Nevertheless, in the absence of a definitive cure, the utilisation of preclinical models remains imperative for the identification of novel therapeutic targets and the evaluation of potential therapeutic agents. Drosophila melanogaster is a model system that can be used as a research tool to investigate neurodegeneration and therapeutic interventions. The short lifespan, low price and ease of husbandry/rearing make Drosophila an advantageous model organism from a practical perspective. However, it is the highly conserved genome and similarity of Drosophila and human neurobiology which make flies a powerful tool to investigate neurodegenerative mechanisms. In addition, the ease of transgenic modifications allows for early proof of principle studies for future therapeutic approaches in neurodegenerative research. This mini review will specifically focus on utilising Drosophila as an in vivo model of amyloid toxicity in AD.
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Affiliation(s)
- Elli Tsintzas
- Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, University College London, London, UK
| | - Teresa Niccoli
- Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, University College London, London, UK
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2
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Odorčić I, Hamed MB, Lismont S, Chávez-Gutiérrez L, Efremov RG. Apo and Aβ46-bound γ-secretase structures provide insights into amyloid-β processing by the APH-1B isoform. Nat Commun 2024; 15:4479. [PMID: 38802343 PMCID: PMC11130327 DOI: 10.1038/s41467-024-48776-2] [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: 08/29/2023] [Accepted: 05/07/2024] [Indexed: 05/29/2024] Open
Abstract
Deposition of amyloid-β (Aβ) peptides in the brain is a hallmark of Alzheimer's disease. Aβs are generated through sequential proteolysis of the amyloid precursor protein by the γ-secretase complexes (GSECs). Aβ peptide length, modulated by the Presenilin (PSEN) and APH-1 subunits of GSEC, is critical for Alzheimer's pathogenesis. Despite high relevance, mechanistic understanding of the proteolysis of Aβ, and its modulation by APH-1, remain incomplete. Here, we report cryo-EM structures of human GSEC (PSEN1/APH-1B) reconstituted into lipid nanodiscs in apo form and in complex with the intermediate Aβ46 substrate without cross-linking. We find that three non-conserved and structurally divergent APH-1 regions establish contacts with PSEN1, and that substrate-binding induces concerted rearrangements in one of the identified PSEN1/APH-1 interfaces, providing structural basis for APH-1 allosteric-like effects. In addition, the GSEC-Aβ46 structure reveals an interaction between Aβ46 and loop 1PSEN1, and identifies three other H-bonding interactions that, according to functional validation, are required for substrate recognition and efficient sequential catalysis.
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Affiliation(s)
- Ivica Odorčić
- Center for Structural Biology, VIB, Brussels, Belgium
- Structural Biology Brussels, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium
| | - Mohamed Belal Hamed
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium
| | - Sam Lismont
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium
| | - Lucía Chávez-Gutiérrez
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium.
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium.
| | - Rouslan G Efremov
- Center for Structural Biology, VIB, Brussels, Belgium.
- Structural Biology Brussels, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium.
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3
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Luo JE, Li YM. Turning the tide on Alzheimer's disease: modulation of γ-secretase. Cell Biosci 2022; 12:2. [PMID: 34983641 PMCID: PMC8725520 DOI: 10.1186/s13578-021-00738-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 12/17/2021] [Indexed: 12/17/2022] Open
Abstract
Alzheimer's disease (AD) is the most common type of neurodegenerative disorder. Amyloid-beta (Aβ) plaques are integral to the "amyloid hypothesis," which states that the accumulation of Aβ peptides triggers a cascade of pathological events leading to neurodegeneration and ultimately AD. While the FDA approved aducanumab, the first Aβ-targeted therapy, multiple safe and effective treatments will be needed to target the complex pathologies of AD. γ-Secretase is an intramembrane aspartyl protease that is critical for the generation of Aβ peptides. Activity and specificity of γ-secretase are regulated by both obligatory subunits and modulatory proteins. Due to its complex structure and function and early clinical failures with pan inhibitors, γ-secretase has been a challenging drug target for AD. γ-secretase modulators, however, have dramatically shifted the approach to targeting γ-secretase. Here we review γ-secretase and small molecule modulators, from the initial characterization of a subset of NSAIDs to the most recent clinical candidates. We also discuss the chemical biology of γ-secretase, in which small molecule probes enabled structural and functional insights into γ-secretase before the emergence of high-resolution structural studies. Finally, we discuss the recent crystal structures of γ-secretase, which have provided valuable perspectives on substrate recognition and molecular mechanisms of small molecules. We conclude that modulation of γ-secretase will be part of a new wave of AD therapeutics.
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Affiliation(s)
- Joanna E Luo
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA. .,Program of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University, New York, NY, 10021, USA.
| | - Yue-Ming Li
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA. .,Program of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University, New York, NY, 10021, USA.
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4
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Specific Mutations in Aph1 Cause γ-Secretase Activation. Int J Mol Sci 2022; 23:ijms23010507. [PMID: 35008932 PMCID: PMC8745412 DOI: 10.3390/ijms23010507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 12/29/2021] [Accepted: 12/30/2021] [Indexed: 01/25/2023] Open
Abstract
Amyloid beta peptides (Aβs) are generated from amyloid precursor protein (APP) through multiple cleavage steps mediated by γ-secretase, including endoproteolysis and carboxypeptidase-like trimming. The generation of neurotoxic Aβ42/43 species is enhanced by familial Alzheimer's disease (FAD) mutations within the catalytic subunit of γ-secretase, presenilin 1 (PS1). FAD mutations of PS1 cause partial loss-of-function and decrease the cleavage activity. Activating mutations, which have the opposite effect of FAD mutations, are important for studying Aβ production. Aph1 is a regulatory subunit of γ-secretase; it is presumed to function as a scaffold of the complex. In this study, we identified Aph1 mutations that are active in the absence of nicastrin (NCT) using a yeast γ-secretase assay. We analyzed these Aph1 mutations in the presence of NCT; we found that the L30F/T164A mutation is activating. When introduced in mouse embryonic fibroblasts, the mutation enhanced cleavage. The Aph1 mutants produced more short and long Aβs than did the wild-type Aph1, without an apparent modulatory function. The mutants did not change the amount of γ-secretase complex, suggesting that L30F/T164A enhances catalytic activity. Our results provide insights into the regulatory function of Aph1 in γ-secretase activity.
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Mekala S, Nelson G, Li YM. Recent developments of small molecule γ-secretase modulators for Alzheimer's disease. RSC Med Chem 2020; 11:1003-1022. [PMID: 33479693 PMCID: PMC7513388 DOI: 10.1039/d0md00196a] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 07/29/2020] [Indexed: 12/30/2022] Open
Abstract
Alzheimer's disease (AD) is the most common form of progressive neurodegenerative disorder, marked by memory loss and a decline in cognitive function. The major hallmarks of AD are the presence of intracellular neurofibrillary tau tangles (NFTs) composed of hyperphosphorylated tau proteins and extracellular plaques composed of amyloid beta peptides (Aβ). The amyloid (Aβ) cascade hypothesis proposes that the AD pathogenesis is initiated by the accumulation of Aβ peptides in the parenchyma of the brain. An aspartyl intramembranal protease called γ-secretase is responsible for the production of Aβ by the cleavage of the amyloid precursor protein (APP). Clinical studies of γ-secretase inhibitors (GSIs) for AD failed due to the lack of substrate specificity. Therefore, γ-secretase modulators (GSMs) have been developed as potential disease modifying agents to modulate the γ-secretase cleavage activity towards the production of toxic Aβ42 peptides. Following the first-generation 'nonsteroidal anti-inflammatory drug' (NSAID) based GSMs, second-generation GSMs (carboxylic acid based NSAID derivatives and non-NSAID derived heterocyclic analogues), as well as natural product-based GSMs, have been developed. In this review, we focus on the recent developments of small molecule-based GSMs that show potential improvements in terms of drug-like properties as well as their current status in human clinical trials and the future perspectives of GSM research.
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Affiliation(s)
- Shekar Mekala
- Chemical Biology Program , Memorial Sloan-Kettering Cancer Center , 1275 York Avenue , New York , New York 10065 , USA . ;
| | - Grady Nelson
- Chemical Biology Program , Memorial Sloan-Kettering Cancer Center , 1275 York Avenue , New York , New York 10065 , USA . ;
| | - Yue-Ming Li
- Chemical Biology Program , Memorial Sloan-Kettering Cancer Center , 1275 York Avenue , New York , New York 10065 , USA . ;
- Pharmacology Graduate Program , Weill Graduate School of Medical Sciences of Cornell University , New York , New York 10021 , USA
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Yuksel M, Tacal O. Trafficking and proteolytic processing of amyloid precursor protein and secretases in Alzheimer's disease development: An up-to-date review. Eur J Pharmacol 2019; 856:172415. [PMID: 31132354 DOI: 10.1016/j.ejphar.2019.172415] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 04/26/2019] [Accepted: 05/23/2019] [Indexed: 12/25/2022]
Abstract
Alzheimer's disease (AD), which is predicted to affect 1 in 85 persons worldwide by 2050, results in progressive loss of neuronal functions, leading to impairments in memory and cognitive abilities. As being one of the major neuropathological hallmarks of AD, senile plaques mainly consist of amyloid-β (Aβ) peptides, which are derived from amyloid precursor protein (APP) via the sequential cleavage by β- and γ-secretases. Although the overproduction and accumulation of Aβ peptides are at the center of AD research, the new discoveries point out to the complexity of the disease development. In this respect, it is crucial to understand the processing and the trafficking of APP, the enzymes involved in its processing, the cleavage products and their therapeutic potentials. This review summarizes the salient features of APP processing focusing on APP, the canonical secretases as well as the novel secretases and the cleavage products with an update of the recent developments. We also discussed the intracellular trafficking of APP and secretases in addition to their potential in AD therapy.
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Affiliation(s)
- Melike Yuksel
- Department of Biochemistry, School of Pharmacy, Hacettepe University, 06100, Ankara, Turkey.
| | - Ozden Tacal
- Department of Biochemistry, School of Pharmacy, Hacettepe University, 06100, Ankara, Turkey.
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7
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Murray CE, Gami-Patel P, Gkanatsiou E, Brinkmalm G, Portelius E, Wirths O, Heywood W, Blennow K, Ghiso J, Holton JL, Mills K, Zetterberg H, Revesz T, Lashley T. The presubiculum is preserved from neurodegenerative changes in Alzheimer's disease. Acta Neuropathol Commun 2018; 6:62. [PMID: 30029687 PMCID: PMC6053705 DOI: 10.1186/s40478-018-0563-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 06/29/2018] [Indexed: 12/16/2022] Open
Abstract
In the majority of affected brain regions the pathological hallmarks of Alzheimer’s disease (AD) are β-amyloid (Aβ) deposits in the form of diffuse and neuritic plaques, tau pathology in the form of neurofibrillary tangles, neuropil threads and plaque-associated abnormal neurites in combination with an inflammatory response. However, the anatomical area of the presubiculum, is characterised by the presence of a single large evenly distributed ‘lake-like’ Aβ deposit with minimal tau deposition or accumulation of inflammatory markers. Post-mortem brain samples from sporadic AD (SAD) and familial AD (FAD) and two hereditary cerebral amyloid diseases, familial British dementia (FBD) and familial Danish dementia (FDD) were used to compare the morphology of the extracellular proteins deposited in the presubiculum compared to the entorhinal cortex. The level of tau pathology and the extent of microglial activation were quantitated in the two brain regions in SAD and FAD. Frozen tissue was used to investigate the Aβ species and proteomic differences between the two regions. Consistent with our previous investigations of FBD and FDD cases we were able to establish that the ‘lake-like’ pre-amyloid deposits of the presubiculum were not a unique feature of AD but they also found two non-Aβ amyloidosis. Comparing the presubiculum to the entorhinal cortex the number of neurofibrillary tangles and tau load were significantly reduced; there was a reduction in microglial activation; there were differences in the Aβ profiles and the investigation of the whole proteome showed significant changes in different protein pathways. In summary, understanding why the presubiculum has a different morphological appearance, biochemical and proteomic makeup compared to surrounding brain regions severely affected by neurodegeneration could lead us to understanding protective mechanisms in neurodegenerative diseases.
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Effects and Mechanism of Huannao Yicong Decoction Extract on the Ethology of Transgenic APP/PS1 Mice. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2017; 2017:9502067. [PMID: 29422937 PMCID: PMC5750494 DOI: 10.1155/2017/9502067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2017] [Accepted: 09/11/2017] [Indexed: 01/16/2023]
Abstract
To investigate the mechanism of Huannao Yicong Decoction (HYD) extract on improving of learning memory of transgenic amyloid precursor protein (APP)/presenilin 1 (PS1) mice, we randomly divided 60 transgenic APP/PS1 mice of 3 months old into 4 groups: the model group, the Donepezil group, the HYD-L group, and the HYD-H group, with 15 C57BL/6J mice of the same genetic background as the control group. These mice were gavaged for 6 months in a row. The results showed that the latency was significantly shortened and the number of passing through the original platform was increased. HYD extract can increase the amount of neurons and improve the morphological structure of Nissl body obviously. The γ-secretase activity and the expression of phosphorylated APP, Aβ1-40, and Aβ1-42 in hippocampal CA1 were significantly decreased. The expressions of protein and mRNA of PEN-2 and CREB in hippocampal were significantly downregulated. These results demonstrated that HYD extract can improve the memory ability of transgenic APP/PS1 mice, which was related to the protection of neurons and structure of Nissl body, reducing cleavage of APP and production of Aβ and inhibiting the activity of γ-secretase by decreasing CREB activity because of downregulated expression of PEN-2.
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9
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Kanatsu K, Tomita T. Membrane trafficking and proteolytic activity of γ-secretase in Alzheimer’s disease. Biol Chem 2016; 397:827-35. [DOI: 10.1515/hsz-2016-0146] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 07/04/2016] [Indexed: 12/26/2022]
Abstract
Abstract
γ-Secretase is an intramembrane-cleaving protease that generates various forms of amyloid-β peptides (Aβ) that accumulate in the brains of Alzheimer’s disease (AD) patients. The intracellular trafficking and subcellular localization of γ-secretase are linked to both qualitative and quantitative changes in Aβ production. However, the precise intracellular localization of γ-secretase as well as its detailed regulatory mechanisms have remained elusive. Recent genetic studies on AD provide ample evidence that alteration of the subcellular localization of γ-secretase contributes to the pathogenesis of AD. Here we review our current understanding of the intracellular membrane trafficking of γ-secretase, the association between its localization and proteolytic activity, and the possibility of γ-secretase as a therapeutic target against AD.
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10
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Carroll CM, Li YM. Physiological and pathological roles of the γ-secretase complex. Brain Res Bull 2016; 126:199-206. [PMID: 27133790 DOI: 10.1016/j.brainresbull.2016.04.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 04/19/2016] [Accepted: 04/27/2016] [Indexed: 12/27/2022]
Abstract
Gamma-secretase (GS) is an enzyme complex that cleaves numerous substrates, and it is best known for cleaving amyloid precursor protein (APP) to form amyloid-beta (Aβ) peptides. Aberrant cleavage of APP can lead to Alzheimer's disease, so much research has been done to better understand GS structure and function in hopes of developing therapeutics for Alzheimer's. Therefore, most of the attention in this field has been focused on developing modulators that reduce pathogenic forms of Aβ while leaving Notch and other GS substrates intact, but GS provides multiple avenues of modulation that could improve AD pathology. GS has complex regulation, through its essential subunits and other associated proteins, providing other targets for AD drugs. Therapeutics can also alter GS trafficking and thereby improve cognition, or move beyond Aβ entirely, effecting Notch and neural stem cells. GS also cleaves substrates that affect synaptic morphology and function, presenting another window by which GS modulation could improve AD pathology. Taken together, GS presents a unique cross road for neural processes and an ideal target for AD therapeutics.
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Affiliation(s)
- Courtney M Carroll
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, NY, United States; Program of Neuroscience, Weill Graduate School of Medical Sciences of Cornell University, NY, United States.
| | - Yue-Ming Li
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, NY, United States; Program of Neuroscience, Weill Graduate School of Medical Sciences of Cornell University, NY, United States; Program of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University, NY, United States
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Hydrogen Sulfide Selectively Inhibits γ-Secretase Activity and Decreases Mitochondrial Aβ Production in Neurons from APP/PS1 Transgenic Mice. Neurochem Res 2015; 41:1145-59. [PMID: 26708452 DOI: 10.1007/s11064-015-1807-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 12/11/2015] [Accepted: 12/12/2015] [Indexed: 10/22/2022]
Abstract
Hydrogen sulfide (H2S) is now considered to be a gasotransmitter and may be involved in the pathological process of Alzheimer's disease (AD). A majority of APP is associated with mitochondria and is a substrate for the mitochondrial γ-secretase. The mitochondria-associated APP metabolism where APP intracellular domains (AICD) and Aβ are generated locally and may contribute to mitochondrial dysfunction in AD. Here, we aimed to investigate the ability of H2S to mediate APP processing in mitochondria and assessed the possible mechanisms underlying H2S-mediated AD development. We treated neurons from APP/PS1 transgenic mice with a range of sodium hydrosulfide (NaHS) concentrations. NaHS attenuated APP processing and decreased Aβ production in mitochondria. Meanwhile, NaHS did not changed BACE-1 and ADAM10 (a disintegrin and metalloprotease 10) protein levels, but NaHS (30 μM) significantly increased the levels of presenilin 1(PS1), PEN-2, and NCT, as well as improved the γ-secretase activity, while NaHS (50 μM) exhibits the opposing effects. Furthermore, the intracellular ATP and the COX IV activity of APP/PS1 neurons were increased after 30 μM NaHS treatment, while the ROS level was decreased and the MMP was stabilized. The effect of NaHS differs from DAPT (a non-selective γ-secretase inhibitor), and it selectively inhibited γ-secretase in vitro, without interacting with Notch and modulating its cleavage. The results indicated that NaHS decreases Aβ accumulation in mitochondria by selectively inhibiting γ-secretase. Thus, we provide a mechanistic view of NaHS is a potential anti-AD drug candidate and it may decrease Aβ deposition in mitochondria by selectively inhibiting γ-secretase activity and therefore protecting the mitochondrial function during AD conditions.
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12
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Marinangeli C, Tasiaux B, Opsomer R, Hage S, Sodero AO, Dewachter I, Octave JN, Smith SO, Constantinescu SN, Kienlen-Campard P. Presenilin transmembrane domain 8 conserved AXXXAXXXG motifs are required for the activity of the γ-secretase complex. J Biol Chem 2015; 290:7169-84. [PMID: 25614624 DOI: 10.1074/jbc.m114.601286] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Understanding the molecular mechanisms controlling the physiological and pathological activity of γ-secretase represents a challenging task in Alzheimer disease research. The assembly and proteolytic activity of this enzyme require the correct interaction of the 19 transmembrane domains (TMDs) present in its four subunits, including presenilin (PS1 or PS2), the γ-secretase catalytic core. GXXXG and GXXXG-like motifs are critical for TMDs interactions as well as for protein folding and assembly. The GXXXG motifs on γ-secretase subunits (e.g. APH-1) or on γ-secretase substrates (e.g. APP) are known to be involved in γ-secretase assembly and in Aβ peptide production, respectively. We identified on PS1 and PS2 TMD8 two highly conserved AXXXAXXXG motifs. The presence of a mutation causing an inherited form of Alzheimer disease (familial Alzheimer disease) in the PS1 motif suggested their involvement in the physiopathological configuration of the γ-secretase complex. In this study, we targeted the role of these motifs on TMD8 of PSs, focusing on their role in PS assembly and catalytic activity. Each motif was mutated, and the impact on complex assembly, activity, and substrate docking was monitored. Different amino acid substitutions on the same motif resulted in opposite effects on γ-secretase activity, without affecting the assembly or significantly impairing the maturation of the complex. Our data suggest that AXXXAXXXG motifs in PS TMD8 are key determinants for the conformation of the mature γ-secretase complex, participating in the switch between the physiological and pathological functional conformations of the γ-secretase.
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Affiliation(s)
| | | | | | - Salim Hage
- the Louvain Drug Research Institute, and
| | | | | | | | - Steven O Smith
- the Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794-5215
| | - Stefan N Constantinescu
- the de Duve Institute and Ludwig Institute for Cancer Research, Université Catholique de Louvain, Brussels 1200, Belgium and
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Zhang X, Hoey R, Koide A, Dolios G, Paduch M, Nguyen P, Wu X, Li Y, Wagner SL, Wang R, Koide S, Sisodia SS. A synthetic antibody fragment targeting nicastrin affects assembly and trafficking of γ-secretase. J Biol Chem 2014; 289:34851-61. [PMID: 25352592 DOI: 10.1074/jbc.m114.609636] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The γ-secretase complex, composed of presenilin, nicastrin (NCT), anterior pharynx-defective 1 (APH-1), and presenilin enhancer 2 (PEN-2), is assembled in a highly regulated manner and catalyzes the intramembranous proteolysis of many type I membrane proteins, including Notch and amyloid precursor protein. The Notch family of receptors plays important roles in cell fate specification during development and in adult tissues, and aberrant hyperactive Notch signaling causes some forms of cancer. γ-Secretase-mediated processing of Notch at the cell surface results in the generation of the Notch intracellular domain, which associates with several transcriptional coactivators involved in nuclear signaling events. On the other hand, γ-secretase-mediated processing of amyloid precursor protein leads to the production of amyloid β (Aβ) peptides that play an important role in the pathogenesis of Alzheimer disease. We used a phage display approach to identify synthetic antibodies that specifically target NCT and expressed them in the single-chain variable fragment (scFv) format in mammalian cells. We show that expression of a NCT-specific scFv clone, G9, in HEK293 cells decreased the production of the Notch intracellular domain but not the production of amyloid β peptides that occurs in endosomal and recycling compartments. Biochemical studies revealed that scFvG9 impairs the maturation of NCT by associating with immature forms of NCT and, consequently, prevents its association with the other components of the γ-secretase complex, leading to degradation of these molecules. The reduced cell surface levels of mature γ-secretase complexes, in turn, compromise the intramembranous processing of Notch.
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Affiliation(s)
| | - Robert Hoey
- Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637
| | - Akiko Koide
- Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637
| | - Georgia Dolios
- the Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Marcin Paduch
- Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637
| | - Phuong Nguyen
- the Department of Neurosciences, University of California, San Diego School of Medicine, La Jolla, California 92093, and
| | - Xianzhong Wu
- Molecular Pharmacology and Chemistry, Memorial Sloan-Kettering Cancer Center, New York, New York 10065
| | - Yueming Li
- Molecular Pharmacology and Chemistry, Memorial Sloan-Kettering Cancer Center, New York, New York 10065
| | - Steven L Wagner
- the Department of Neurosciences, University of California, San Diego School of Medicine, La Jolla, California 92093, and
| | - Rong Wang
- the Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Shohei Koide
- Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637
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14
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Smolarkiewicz M, Skrzypczak T, Michalak M, Leśniewicz K, Walker JR, Ingram G, Wojtaszek P. Gamma-secretase subunits associate in intracellular membrane compartments in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3015-27. [PMID: 24723404 PMCID: PMC4071823 DOI: 10.1093/jxb/eru147] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Gamma-secretase is a multisubunit complex with intramembrane proteolytic activity. In humans it was identified in genetic screens of patients suffering from familial forms of Alzheimer's disease, and since then it was shown to mediate cleavage of more than 80 substrates, including amyloid precursor protein or Notch receptor. Moreover, in animals, γ-secretase was shown to be involved in regulation of a wide range of cellular events, including cell signalling, regulation of endocytosis of membrane proteins, their trafficking, and degradation. Here we show that genes coding for γ-secretase homologues are present in plant genomes. Also, amino acid motifs crucial for γ-secretase activity are conserved in plants. Moreover, all γ-secretase subunits: PS1/PS2, APH-1, PEN-2, and NCT colocalize and interact with each other in Arabidopsis thaliana protoplasts. The intracellular localization of γ-secretase subunits in Arabidopsis protoplasts revealed a distribution in endomembrane system compartments that is consistent with data from animal studies. Together, our data may be considered as a starting point for analysis of γ-secretase in plants.
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Affiliation(s)
- Michalina Smolarkiewicz
- Department of Molecular and Cellular Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Tomasz Skrzypczak
- Department of Molecular and Cellular Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Michał Michalak
- Department of Molecular and Cellular Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Krzysztof Leśniewicz
- Department of Molecular and Cellular Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - J Ross Walker
- Institute of Molecular Plant Sciences, University of Edinburgh, King's Buildings, Mayfield Rd, Edinburgh EH9 3JH, UK
| | - Gwyneth Ingram
- Institute of Molecular Plant Sciences, University of Edinburgh, King's Buildings, Mayfield Rd, Edinburgh EH9 3JH, UK UMR 5667 CNRS-INRA-ENSL-UCB Lyon I, Reproduction et Développement des Plantes, ENS Lyon, 46, Allée d'Italie, 69364 LYON Cedex 07, France
| | - Przemysław Wojtaszek
- Department of Molecular and Cellular Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
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15
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Tomita T. Secretase inhibitors and modulators for Alzheimer’s disease treatment. Expert Rev Neurother 2014; 9:661-79. [DOI: 10.1586/ern.09.24] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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16
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Jurisch-Yaksi N, Sannerud R, Annaert W. A fast growing spectrum of biological functions of γ-secretase in development and disease. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2815-27. [PMID: 24099003 DOI: 10.1016/j.bbamem.2013.04.016] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 04/03/2013] [Accepted: 04/11/2013] [Indexed: 12/17/2022]
Abstract
γ-secretase, which assembles as a tetrameric complex, is an aspartyl protease that proteolytically cleaves substrate proteins within their membrane-spanning domain; a process also known as regulated intramembrane proteolysis (RIP). RIP regulates signaling pathways by abrogating or releasing signaling molecules. Since the discovery, already >15 years ago, of its catalytic component, presenilin, and even much earlier with the identification of amyloid precursor protein as its first substrate, γ-secretase has been commonly associated with Alzheimer's disease. However, starting with Notch and thereafter a continuously increasing number of novel substrates, γ-secretase is becoming linked to an equally broader range of biological processes. This review presents an updated overview of the current knowledge on the diverse molecular mechanisms and signaling pathways controlled by γ-secretase, with a focus on organ development, homeostasis and dysfunction. This article is part of a Special Issue entitled: Intramembrane Proteases.
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Affiliation(s)
- Nathalie Jurisch-Yaksi
- Laboratory for Membrane Trafficking, VIB-Center for the Biology of Disease & Department for Human Genetics (KU Leuven), Leuven, Belgium
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17
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Trafficking in neurons: Searching for new targets for Alzheimer's disease future therapies. Eur J Pharmacol 2013; 719:84-106. [DOI: 10.1016/j.ejphar.2013.07.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 07/11/2013] [Indexed: 11/22/2022]
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18
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Zhang X, Song W. The role of APP and BACE1 trafficking in APP processing and amyloid-β generation. ALZHEIMERS RESEARCH & THERAPY 2013; 5:46. [PMID: 24103387 PMCID: PMC3978418 DOI: 10.1186/alzrt211] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Neuritic plaques in the brain are a major neuropathological hallmark of Alzheimer’s disease. They are formed by the deposition and aggregation of extracellular amyloid-β protein (Aβ). Aβ is derived from the sequential cleavage of amyloid-β precursor protein (APP) by β-secretase and γ-secretase. β-Site APP cleaving enzyme 1 (BACE1) functions as the primary, if not sole, β-secretase in vivo and is essential for Aβ production. Regulation of APP processing is a major focus of research into AD pathogenesis. The trafficking systems of APP and its cleavage enzymes are complex. Transporting APP and secretases into the same subcellular organelles facilitates their interaction and favors APP processing. The role of APP and BACE1 trafficking in the amyloidgenic pathway and the underlying mechanisms for Aβ production are discussed in this review. In addition, the distinct mechanisms of amino- and carboxy-terminal Aβ generation are reviewed.
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Affiliation(s)
- Xiaojie Zhang
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, Graduate Program in Neuroscience, The University of British Columbia, 2255 Wesbrook Mall, Vancouver BC V6T 1Z3, Canada
| | - Weihong Song
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, Graduate Program in Neuroscience, The University of British Columbia, 2255 Wesbrook Mall, Vancouver BC V6T 1Z3, Canada
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19
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Crump CJ, Johnson DS, Li YM. Development and mechanism of γ-secretase modulators for Alzheimer's disease. Biochemistry 2013; 52:3197-216. [PMID: 23614767 DOI: 10.1021/bi400377p] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
γ-Secretase is an aspartyl intramembranal protease composed of presenilin, Nicastrin, Aph1, and Pen2 with 19 transmembrane domains. γ-Secretase cleaves the amyloid precursor proteins (APP) to release Aβ peptides that likely play a causative role in the pathogenesis of Alzheimer's disease (AD). In addition, γ-secretase cleaves Notch and other type I membrane proteins. γ-Secretase inhibitors (GSIs) have been developed and used for clinical studies. However, clinical trials have shown adverse effects of GSIs that are potentially linked with nondiscriminatory inhibition of Notch signaling, overall APP processing, and other substrate cleavages. Therefore, these findings call for the development of disease-modifying agents that target γ-secretase activity to lower levels of Aβ42 production without blocking the overall processing of γ-secretase substrates. γ-Secretase modulators (GSMs) originally derived from nonsteroidal anti-inflammatory drugs (NSAIDs) display such characteristics and are the focus of this review. However, first-generation GSMs have limited potential because of the low potency and undesired neuropharmacokinetic properties. This generation of GSMs has been suggested to interact with the APP substrate, γ-secretase, or both. To improve the potency and brain availability, second-generation GSMs, including NSAID-derived carboxylic acid and non-NSAID-derived heterocyclic chemotypes, as well as natural product-derived GSMs have been developed. Animal studies of this generation of GSMs have shown encouraging preclinical profiles. Moreover, using potent GSM photoaffinity probes, multiple studies unambiguously have showed that both carboxylic acid and heterocyclic GSMs specifically target presenilin, the catalytic subunit of γ-secretase. In addition, two types of GSMs have distinct binding sites within the γ-secretase complex and exhibit different Aβ profiles. GSMs induce a conformational change of γ-secretase to achieve modulation. Various models are proposed and discussed. Despite the progress of GSM research, many outstanding issues remain to be investigated to achieve the ultimate goal of developing GSMs as effective AD therapies.
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Affiliation(s)
- Christina J Crump
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center , 1275 York Avenue, New York, New York 10065, United States
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20
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Tomita T, Iwatsubo T. Structural biology of presenilins and signal peptide peptidases. J Biol Chem 2013; 288:14673-80. [PMID: 23585568 DOI: 10.1074/jbc.r113.463281] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Presenilin and signal peptide peptidase are multispanning intramembrane-cleaving proteases with a conserved catalytic GxGD motif. Presenilin comprises the catalytic subunit of γ-secretase, a protease responsible for the generation of amyloid-β peptides causative of Alzheimer disease. Signal peptide peptidase proteins are implicated in the regulation of the immune system. Both protease family proteins have been recognized as druggable targets for several human diseases, but their detailed structure still remains unknown. Recently, the x-ray structures of some archaeal GxGD proteases have been determined. We review the recent progress in biochemical and biophysical probing of the structure of these atypical proteases.
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Affiliation(s)
- Taisuke Tomita
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.
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21
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Pink AE, Simpson MA, Desai N, Trembath RC, Barker JN. γ-Secretase Mutations in Hidradenitis Suppurativa: New Insights into Disease Pathogenesis. J Invest Dermatol 2013; 133:601-607. [DOI: 10.1038/jid.2012.372] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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22
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Mo JS, Yoon JH, Hong JA, Kim MY, Ann EJ, Ahn JS, Kim SM, Baek HJ, Lang F, Choi EJ, Park HS. Phosphorylation of nicastrin by SGK1 leads to its degradation through lysosomal and proteasomal pathways. PLoS One 2012; 7:e37111. [PMID: 22590650 PMCID: PMC3349648 DOI: 10.1371/journal.pone.0037111] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 04/13/2012] [Indexed: 12/18/2022] Open
Abstract
The gamma-secretase complex is involved in the intramembranous proteolysis of a variety of substrates, including the amyloid precursor protein and the Notch receptor. Nicastrin (NCT) is an essential component of the gamma-secretase complex and functions as a receptor for gamma-secretase substrates. In this study, we determined that serum- and glucocorticoid-induced protein kinase 1 (SGK1) markedly reduced the protein stability of NCT. The SGK1 kinase activity was decisive for NCT degradation and endogenous SGK1 inhibited gamma-secretase activity. SGK1 downregulates NCT protein levels via proteasomal and lysosomal pathways. Furthermore, SGK1 directly bound to and phosphorylated NCT on Ser437, thereby promoting protein degradation. Collectively, our findings indicate that SGK1 is a gamma-secretase regulator presumably effective through phosphorylation and degradation of NCT.
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Affiliation(s)
- Jung-Soon Mo
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
| | - Ji-Hye Yoon
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
| | - Ji-Ae Hong
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
| | - Mi-Yeon Kim
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
| | - Eun-Jung Ann
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
| | - Ji-Seon Ahn
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
| | - Su-Man Kim
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
| | - Hyeong-Jin Baek
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
| | - Florian Lang
- Department of Physiology, University of Tübingen, Tübingen, Germany
| | - Eui-Ju Choi
- School of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea
| | - Hee-Sae Park
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
- * E-mail:
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23
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Rajendran L, Annaert W. Membrane Trafficking Pathways in Alzheimer's Disease. Traffic 2012; 13:759-70. [DOI: 10.1111/j.1600-0854.2012.01332.x] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 01/20/2012] [Accepted: 01/23/2012] [Indexed: 11/28/2022]
Affiliation(s)
- Lawrence Rajendran
- Systems and Cell Biology of Neurodegeneration; Division of Psychiatry Research; University of Zurich; August-Forel Str. 1; Zurich; 8008; Switzerland
| | - Wim Annaert
- Laboratory for Membrane Trafficking; Center for Human Genetics (KULeuven) & VIB-Center for the Biology of Disease; Gasthuisberg O&N4, Herestraat 49; Leuven; B-3000; Belgium
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24
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D'Onofrio G, Panza F, Frisardi V, Solfrizzi V, Imbimbo BP, Paroni G, Cascavilla L, Seripa D, Pilotto A. Advances in the identification of γ-secretase inhibitors for the treatment of Alzheimer's disease. Expert Opin Drug Discov 2011; 7:19-37. [DOI: 10.1517/17460441.2012.645534] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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25
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Zhang H, Ma Q, Zhang YW, Xu H. Proteolytic processing of Alzheimer's β-amyloid precursor protein. J Neurochem 2011; 120 Suppl 1:9-21. [PMID: 22122372 DOI: 10.1111/j.1471-4159.2011.07519.x] [Citation(s) in RCA: 231] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
β-Amyloid precursor protein (APP) is a critical factor in the pathogenesis of Alzheimer's disease (AD). APP undergoes post-translational proteolysis/processing to generate the hydrophobic β-amyloid (Aβ) peptides. Deposition of Aβ in the brain, forming oligomeric Aβ and plaques, is identified as one of the key pathological hallmarks of AD. The processing of APP to generate Aβ is executed by β- and γ-secretase and is highly regulated. Aβ toxicity can lead to synaptic dysfunction, neuronal cell death, impaired learning/memory and abnormal behaviors in AD models in vitro and in vivo. Aside from Aβ, proteolytic cleavages of APP can also give rise to the APP intracellular domain, reportedly involved in multiple types of cellular events such as gene transcription and apoptotic cell death. In addition to amyloidogenic processing, APP can also be cleaved by α-secretase to form a soluble or secreted APP ectodomain (sAPP-α) that has been shown to be mostly neuro-protective. In this review, we describe the mechanisms involved in APP metabolism and the likely functions of its various proteolytic products to give a better understanding of the patho/physiological functions of APP.
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Affiliation(s)
- Han Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, College of Medicine, Xiamen University, Xiamen, Fujian, China.,Neurodegenerative Disease Research Program, Sanford-Burnham Medical Research Institute, La Jolla, California, USA
| | - Qilin Ma
- Department of Neurology, The First Affiliated Hospital of Xiamen University, Xiamen, Fujian, China
| | - Yun-Wu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, College of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, College of Medicine, Xiamen University, Xiamen, Fujian, China.,Neurodegenerative Disease Research Program, Sanford-Burnham Medical Research Institute, La Jolla, California, USA
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26
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Yonemura Y, Futai E, Yagishita S, Suo S, Tomita T, Iwatsubo T, Ishiura S. Comparison of presenilin 1 and presenilin 2 γ-secretase activities using a yeast reconstitution system. J Biol Chem 2011; 286:44569-75. [PMID: 22074918 DOI: 10.1074/jbc.m111.270108] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
γ-Secretase is composed of at least four proteins, presenilin (PS), nicastrin (NCT), Aph1, and Pen2. PS is the catalytic subunit of the γ-secretase complex, having aspartic protease activity. PS has two homologs, namely, PS1 and PS2. To compare the activity of these complexes containing different PSs, we reconstituted them in yeast, which lacks γ-secretase homologs. Yeast cells were transformed with PS1 or PS2, NCT, Pen2, Aph1, and artificial substrate C55-Gal4p. After substrate cleavage, Gal4p translocates to the nucleus and activates transcription of the reporter genes ADE2, HIS3, and lacZ. γ-Secretase activity was measured based on yeast growth on selective media and β-galactosidase activity. PS1 γ-secretase was ∼24-fold more active than PS2 γ-secretase in the β-galactosidase assay. Using yeast microsomes containing γ-secretase and C55, we compared the concentration of Aβ generated by PS1 or PS2 γ-secretase. PS1 γ-secretase produced ∼24-fold more Aβ than PS2 γ-secretase. We found the optimal pH of Aβ production by PS2 to be 7.0, as for PS1, and that the PS2 complex included immature NCT, unlike the PS1 complex, which included mature NCT. In this study, we compared the activity of PS1 or PS2 per one γ-secretase complex. Co-immunoprecipitation experiments using yeast microsomes showed that PS1 concentrations in the γ-secretase complex were ∼28 times higher than that of PS2. Our data suggest that the PS1 complex is only marginally less active than the PS2 complex in Aβ production.
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Affiliation(s)
- Yoji Yonemura
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902, Japan
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27
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γ-secretase inhibitors for treating Alzheimer’s disease: rationale and clinical data. ACTA ACUST UNITED AC 2011. [DOI: 10.4155/cli.11.86] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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28
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Fraering PC. Structural and Functional Determinants of gamma-Secretase, an Intramembrane Protease Implicated in Alzheimer's Disease. Curr Genomics 2011; 8:531-49. [PMID: 19415127 PMCID: PMC2647162 DOI: 10.2174/138920207783769521] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Revised: 12/27/2007] [Accepted: 12/27/2007] [Indexed: 12/28/2022] Open
Abstract
Alzheimer’s disease is the most common form of neurodegenerative diseases in humans, characterized by the progressive accumulation and aggregation of amyloid-β peptides (Aβ) in brain regions subserving memory and cognition. These 39-43 amino acids long peptides are generated by the sequential proteolytic cleavages of the amyloid-β precursor protein (APP) by β- and γ-secretases, with the latter being the founding member of a new class of intramembrane-cleaving proteases (I-CliPs) characterized by their intramembranous catalytic residues hydrolyzing the peptide bonds within the transmembrane regions of their respective substrates. These proteases include the S2P family of metalloproteases, the Rhomboid family of serine proteases, and two aspartyl proteases: the signal peptide peptidase (SPP) and γ-secretase. In sharp contrast to Rhomboid and SPP that function as a single component, γ-secretase is a multi-component protease with complex assembly, maturation and activation processes. Recently, two low-resolution three-dimensional structures of γ-secretase and three high-resolution structures of the GlpG rhomboid protease have been obtained almost simultaneously by different laboratories. Although these proteases are unrelated by sequence or evolution, they seem to share common functional and structural mechanisms explaining how they catalyze intramembrane proteolysis. Indeed, a water-containing chamber in the catalytic cores of both γ-secretase and GlpG rhomboid provides the hydrophilic environment required for proteolysis and a lateral gating mechanism controls substrate access to the active site. The studies that have identified and characterized the structural determinants critical for the assembly and activity of the γ-secretase complex are reviewed here.
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Affiliation(s)
- Patrick C Fraering
- Brain Mind Institute and School of Life Sciences, Swiss Federal Institute of Technology (EPFL), CH-1015 Lausanne, Switzerland
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29
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Renzi F, Zhang X, Rice WJ, Torres-Arancivia C, Gomez-Llorente Y, Diaz R, Ahn K, Yu C, Li YM, Sisodia SS, Ubarretxena-Belandia I. Structure of gamma-secretase and its trimeric pre-activation intermediate by single-particle electron microscopy. J Biol Chem 2011; 286:21440-9. [PMID: 21454611 PMCID: PMC3122203 DOI: 10.1074/jbc.m110.193326] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 03/09/2011] [Indexed: 11/06/2022] Open
Abstract
The γ-secretase membrane protein complex is responsible for proteolytic maturation of signaling precursors and catalyzes the final step in the production of the amyloid β-peptides implicated in the pathogenesis of Alzheimer disease. The incorporation of PEN-2 (presenilin enhancer 2) into a pre-activation intermediate, composed of the catalytic subunit presenilin and the accessory proteins APH-1 (anterior pharynx-defective 1) and nicastrin, triggers the endoproteolysis of presenilin and results in an active tetrameric γ-secretase. We have determined the three-dimensional reconstruction of a mature and catalytically active γ-secretase using single-particle cryo-electron microscopy. γ-Secretase has a cup-like shape with a lateral belt of ∼40-50 Å in height that encloses a water-accessible internal chamber. Active site labeling with a gold-coupled transition state analog inhibitor suggested that the γ-secretase active site faces this chamber. Comparison with the structure of a trimeric pre-activation intermediate suggested that the incorporation of PEN-2 might contribute to the maturation of the active site architecture.
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Affiliation(s)
- Fabiana Renzi
- From the Department of Structural and Chemical Biology, Mount Sinai School of Medicine, New York, New York 10029
- the Universita' di Roma “La Sapienza” 2, Rome 00185, Italy
| | - Xulun Zhang
- the Department of Neurobiology, The University of Chicago, Chicago, Illinois 60637
| | - William J. Rice
- the New York Structural Biology Center, New York, New York 10027
| | - Celia Torres-Arancivia
- From the Department of Structural and Chemical Biology, Mount Sinai School of Medicine, New York, New York 10029
- the Graduate Center, City University of New York, New York, New York 10016
| | - Yacob Gomez-Llorente
- From the Department of Structural and Chemical Biology, Mount Sinai School of Medicine, New York, New York 10029
| | - Ruben Diaz
- the New York Structural Biology Center, New York, New York 10027
| | - Kwangwook Ahn
- the Memorial Sloan-Kettering Cancer Center, New York, New York 10065, and
| | - Chunjiang Yu
- the Department of Anatomy and Cell Biology, the University of Illinois, Chicago, Illinois 60612
| | - Yue-Ming Li
- the Memorial Sloan-Kettering Cancer Center, New York, New York 10065, and
| | - Sangram S. Sisodia
- the Department of Neurobiology, The University of Chicago, Chicago, Illinois 60637
| | - Iban Ubarretxena-Belandia
- From the Department of Structural and Chemical Biology, Mount Sinai School of Medicine, New York, New York 10029
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30
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Imbimbo BP, Panza F, Frisardi V, Solfrizzi V, D'Onofrio G, Logroscino G, Seripa D, Pilotto A. Therapeutic intervention for Alzheimer's disease with γ-secretase inhibitors: still a viable option? Expert Opin Investig Drugs 2011; 20:325-41. [DOI: 10.1517/13543784.2011.550572] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Bruno P Imbimbo
- Research & Development Department, Chiesi Farmaceutici, Via Palermo 26/A, 43100 Parma, Italy ;
| | - Francesco Panza
- Geriatric Unit and Gerontology-Geriatrics Research Laboratory, Department of Medical Sciences, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Foggia, Italy
| | - Vincenza Frisardi
- University of Bari, Center for Aging Brain, Department of Geriatrics, Memory Unit, Bari, Italy
| | - Vincenzo Solfrizzi
- University of Bari, Center for Aging Brain, Department of Geriatrics, Memory Unit, Bari, Italy
| | - Grazia D'Onofrio
- Geriatric Unit and Gerontology-Geriatrics Research Laboratory, Department of Medical Sciences, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Foggia, Italy
| | - Giancarlo Logroscino
- University of Bari, Department of Neurological and Psychiatric Sciences, Bari, Italy
| | - Davide Seripa
- Geriatric Unit and Gerontology-Geriatrics Research Laboratory, Department of Medical Sciences, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Foggia, Italy
| | - Alberto Pilotto
- Geriatric Unit and Gerontology-Geriatrics Research Laboratory, Department of Medical Sciences, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Foggia, Italy
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31
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Reduced Alzheimer's disease ß-amyloid deposition in transgenic mice expressing S-palmitoylation-deficient APH1aL and nicastrin. J Neurosci 2011; 30:16160-9. [PMID: 21123562 DOI: 10.1523/jneurosci.4436-10.2010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Sequential cleavage of amyloid precursor protein by β- and γ-secretases generates β-amyloid peptides (Aβ), which accumulate in the brains of patients with Alzheimer's disease. We recently identified S-palmitoylation of two γ-secretase subunits, APH1 and nicastrin. S-Palmitoylation is an essential posttranslational modification for the proper trafficking and function of many neuronal proteins. In cultured cell lines, lack of S-palmitoylation causes instability of nascent APH1 and nicastrin but does not affect γ-secretase processing of amyloid precursor protein. To determine the importance of γ-secretase S-palmitoylation for Aβ deposition in the brain, we generated transgenic mice coexpressing human wild-type or S-palmitoylation-deficient APH1aL and nicastrin in neurons in the forebrain. We found that lack of S-palmitoylation did not impair the ability of APH1aL and nicastrin to form enzymatically active protein complexes with endogenous presenilin 1 and PEN2 or affect the localization of γ-secretase subunits in dendrites and axons of cortical neurons. When we crossed these mice with 85Dbo transgenic mice, which coexpress familial Alzheimer's disease-causing amyloid precursor protein and presenilin 1 variants, we found that coexpression of wild-type or mutant APH1aL and nicastrin led to marked stabilization of transgenic presenilin 1 in the brains of double-transgenic mice. Interestingly, we observed a moderate, but significant, reduction in amyloid deposits in the forebrain of mice expressing S-palmitoylation-deficient γ-secretase subunits compared with mice overexpressing wild-type subunits, as well as a reduction in the levels of insoluble Aβ(40-42). These results indicate that γ-secretase S-palmitoylation modulates Aβ deposition in the brain.
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32
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Placanica L, Chien JW, Li YM. Characterization of an atypical gamma-secretase complex from hematopoietic origin. Biochemistry 2010; 49:2796-804. [PMID: 20178366 DOI: 10.1021/bi901388t] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Gamma-secretase is a widely expressed multisubunit enzyme complex which is involved in the pathogenesis of Alzheimer disease and hematopoietic malignancies through its aberrant processing of the amyloid precursor protein (APP) and Notch1, respectively. While gamma-secretase has been extensively studied, there is a dearth of information surrounding the activity, composition, and function of gamma-secretase expressed in distinct cellular populations. Here we show that endogenous gamma-secretase complexes of hematopoietic origin are distinct from epithelial derived gamma-secretase complexes. Hematopoietic gamma-secretase has reduced activity for APP and Notch1 processing compared to epithelial gamma-secretase. Characterization of the active complexes with small molecule affinity probes reveals that hematopoietic gamma-secretase has an atypical subunit composition with significantly altered subunit stoichiometry. Furthermore, we demonstrate that these discrete complexes exhibit cell-line specific substrate selectivity suggesting a possible mechanism of substrate regulation. These data underscore the need for studying endogenous gamma-secretase to fully understand of the biology of gamma-secretase and its complexity as a molecular target for the development of disease therapeutics.
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Affiliation(s)
- Lisa Placanica
- Molecular Pharmacology and Chemistry Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
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33
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Watanabe N, Image Image II, Takagi S, Image Image II, Tominaga A, Image Image I, Tomita T, Image Image II, Iwatsubo T, Image Image I. Functional analysis of the transmembrane domains of presenilin 1: participation of transmembrane domains 2 and 6 in the formation of initial substrate-binding site of gamma-secretase. J Biol Chem 2010; 285:19738-46. [PMID: 20418378 DOI: 10.1074/jbc.m110.101287] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
gamma-Secretase is a multimeric membrane protein complex composed of presenilin (PS), nicastrin, Aph-1, and Pen-2, which mediates intramembrane proteolysis of a range of type I transmembrane proteins. We previously analyzed the functional roles of the N-terminal transmembrane domains (TMDs) 1-6 of PS1 in the assembly and proteolytic activity of the gamma-secretase using a series of TMD-swap PS1 mutants. Here we applied the TMD-swap method to all the TMDs of PS1 for the structure-function analysis of the proteolytic mechanism of gamma-secretase. We found that TMD2- or -6-swapped mutant PS1 failed to bind the helical peptide-based, substrate-mimic gamma-secretase inhibitor. Cross-linking experiments revealed that both TMD2 and TMD6 of PS1 locate in proximity to the TMD9, the latter being implicated in the initial substrate binding. Taken together, our data suggest that TMD2 and the luminal side of TMD6 are involved in the formation of the initial substrate-binding site of the gamma-secretase complex.
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Affiliation(s)
- Naoto Watanabe
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
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34
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Jorissen E, De Strooper B. γ-Secretase and the Intramembrane Proteolysis of Notch. Curr Top Dev Biol 2010; 92:201-30. [DOI: 10.1016/s0070-2153(10)92006-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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35
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Krishnaswamy S, Verdile G, Groth D, Kanyenda L, Martins RN. The structure and function of Alzheimer’s gamma secretase enzyme complex. Crit Rev Clin Lab Sci 2009; 46:282-301. [DOI: 10.3109/10408360903335821] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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36
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van de Hoef DL, Hughes J, Livne-Bar I, Garza D, Konsolaki M, Boulianne GL. Identifying genes that interact with Drosophila presenilin and amyloid precursor protein. Genesis 2009; 47:246-60. [PMID: 19241393 DOI: 10.1002/dvg.20485] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The gamma-secretase complex is involved in cleaving transmembrane proteins such as Notch and one of the genes targeted in Alzheimer's disease known as amyloid precursor protein (APP). Presenilins function within the catalytic core of gamma-secretase, and mutated forms of presenilins were identified as causative factors in familial Alzheimer's disease. Recent studies show that in addition to Notch and APP, numerous signal transduction pathways are modulated by presenilins, including intracellular calcium signaling. Thus, presenilins appear to have diverse roles. To further understand presenilin function, we searched for Presenilin-interacting genes in Drosophila by performing a genetic modifier screen for enhancers and suppressors of Presenilin-dependent Notch-related phenotypes. We identified 177 modifiers, including known members of the Notch pathway and genes involved in intracellular calcium homeostasis. We further demonstrate that 53 of these modifiers genetically interacted with APP. Characterization of these genes may provide valuable insights into Presenilin function in development and disease.
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Affiliation(s)
- Diana L van de Hoef
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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37
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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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38
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Hayashi I, Takatori S, Urano Y, Iwanari H, Isoo N, Osawa S, Fukuda MA, Kodama T, Hamakubo T, Li T, Wong PC, Tomita T, Iwatsubo T. Single chain variable fragment against nicastrin inhibits the gamma-secretase activity. J Biol Chem 2009; 284:27838-27847. [PMID: 19684016 DOI: 10.1074/jbc.m109.055061] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gamma-secretase is a membrane protein complex that catalyzes intramembrane proteolysis of a variety of substrates including the amyloid beta precursor protein of Alzheimer disease. Nicastrin (NCT), a single-pass membrane glycoprotein that harbors a large extracellular domain, is an essential component of the gamma-secretase complex. Here we report that overexpression of a single chain variable fragment (scFv) against NCT as an intrabody suppressed the gamma-secretase activity. Biochemical analyses revealed that the scFv disrupted the proper folding and the appropriate glycosyl maturation of the endogenous NCT, which are required for the stability of the gamma-secretase complex and the intrinsic proteolytic activity, respectively, implicating the dual role of NCT in the gamma-secretase complex. Our results also highlight the importance of the calnexin cycle in the functional maturation of the gamma-secretase complex. The engineered intrabodies may serve as rationally designed, molecular targeting tools for the discovery of novel actions of the membrane proteins.
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Affiliation(s)
- Ikuo Hayashi
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Sho Takatori
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yasuomi Urano
- Laboratory for Systems Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Hiroko Iwanari
- Laboratory for Systems Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan; Perseus Proteomics, Inc., 4-7-6 Komaba, Meguro-ku, Tokyo 153-0041, Japan
| | - Noriko Isoo
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Satoko Osawa
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Maiko A Fukuda
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tatsuhiko Kodama
- Laboratory for Systems Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Takao Hamakubo
- Laboratory for Systems Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Tong Li
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Philip C Wong
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Taisuke Tomita
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Takeshi Iwatsubo
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Department of Neuropathology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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39
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Li H, Wolfe MS, Selkoe DJ. Toward structural elucidation of the gamma-secretase complex. Structure 2009; 17:326-34. [PMID: 19278647 DOI: 10.1016/j.str.2009.01.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Revised: 01/12/2009] [Accepted: 01/16/2009] [Indexed: 12/18/2022]
Abstract
Gamma-Secretase is an intramembrane protease complex that mediates the Notch signaling pathway and the production of amyloid beta-proteins. As such, this enzyme has emerged as an important target for development of novel therapeutics for Alzheimer disease and cancer. Great progress has been made in the identification and characterization of the membrane complex and its biological functions. One major challenge now is to illuminate the structure of this fascinating and important protease at atomic resolution. Here, we review recent progress on biochemical and biophysical probing of the structure of the four-component complex and discuss obstacles and potential pathways toward elucidating its detailed structure.
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Affiliation(s)
- Huilin Li
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973-5000, USA.
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40
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Futai E, Yagishita S, Ishiura S. Nicastrin is dispensable for gamma-secretase protease activity in the presence of specific presenilin mutations. J Biol Chem 2009; 284:13013-22. [PMID: 19254953 PMCID: PMC2676034 DOI: 10.1074/jbc.m807653200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
γ-Secretase is a multisubunit membrane protein complex consisting of
presenilin (PS1), nicastrin (NCT), anterior pharynx-1, and presenilin enhancer
2. To analyze the activity of familial Alzheimer disease mutants and to
understand the roles of the subunits, we established a yeast transcriptional
activator Gal4p system with artificial γ-secretase substrates containing
amyloid precursor protein or Notch fragments. The γ-secretase activities
were evaluated by transcriptional activation of reporter genes upon Gal4p
release from the membrane-bound substrates, i.e. growth of yeast on
histidine and adenine, or β-galactosidase assay. We screened and
evaluated γ-secretase mutants using this reconstitution system in yeast,
which does not possess endogenous γ-secretase activity. When we
introduced familial Alzheimer mutants of PS1 in this system, their activities
were shown to be loss of function. Although the protease activity of wild type
PS1 depends on the other three subunits introduced, we obtained 15 new PS1
mutants, which are active in the absence of NCT. They possessed a S438P
mutation at the ninth transmembrane domain (TM9) together with one missense
mutation distributed through transmembrane and loop regions. These mutations
were not related to familial Alzheimer mutations of PS1 as identified so far.
The S438P mutant was partially active but required other mutations for full
activation. Results of the β-galactosidase assay suggested that they have
wild type protease activities, which were further confirmed by the
endoproteolysis of PS1, amyloid β peptides, and Notch intracellular
domain production in mammalian cells. These results suggest that NCT is
dispensable for the protease activity of γ-secretase.
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Affiliation(s)
- Eugene Futai
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan.
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41
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Wang Y, Jia J. Association between promoter polymorphisms in anterior pharynx-defective-1a and sporadic Alzheimer's disease in the North Chinese Han population. Neurosci Lett 2009; 455:101-4. [PMID: 19368855 DOI: 10.1016/j.neulet.2009.02.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 01/28/2009] [Accepted: 02/09/2009] [Indexed: 11/24/2022]
Abstract
Amyloid beta-peptide (Abeta) deposition in brain is important in the development of sporadic Alzheimer's disease (SAD) and Abeta is produced through sequential cleaving of amyloid precursor protein (APP) by beta-secretase and gamma-secrease. Anterior pharynx-defective-1 (APH-1) is an important subunit of the gamma-secretase complex, and its expression level was associated with the activity of gamma-secrease. We hypothesized that alterations in the APH-1 promoter region might alter APH-1 expression and the activity of gamma-secrease, thus be involved in the SAD process. In the present study, we sequenced APH-1a promoter region in 20 randomly selected controls and 20 SAD patients and detected two polymorphisms which were -980C/G (rs3754048) and -21C/A (rs2275780). Then, we investigated genotypes and allele of these two polymorphisms as well as apolipoprotein epsilon4 (APOE epsilon4) status in 256 SAD patients and 276 normal controls with restriction fragment length polymorphisms analysis and sequencing. Results showed the GG genotype and G allele of -980C/G polymorphism were more frequent in the SAD group than that in the controls not only in the whole subjects (genotype P=0.038, allele P=0.01 respectively) but also in the APOE epsilon4+subjects (genotype P=0.048, allele P=0.016 respectively). There was no statistical difference between SAD group and controls regarding to the frequency of alleles and genotypes of -21C/A whenever before or after stratification by APOE epsilon4. Our results suggest that there is an association between -980C/G and the development of SAD in the Northern Han Chinese population and that allele G may interact synergistically with the APOE epsilon4 allele to increase the risk of SAD.
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Affiliation(s)
- Yan Wang
- Department of Neurology, Xuan Wu Hospital of the Capital Medical University, Key Neurodegenerative Laboratory of Ministry of Education of the People's Republic of China, Beijing 100053, China
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42
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Placanica L, Tarassishin L, Yang G, Peethumnongsin E, Kim SH, Zheng H, Sisodia SS, Li YM. Pen2 and presenilin-1 modulate the dynamic equilibrium of presenilin-1 and presenilin-2 gamma-secretase complexes. J Biol Chem 2008; 284:2967-2977. [PMID: 19036728 DOI: 10.1074/jbc.m807269200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
gamma-Secretase is known to play a pivotal role in the pathogenesis of Alzheimer disease through production of amyloidogenic Abeta42 peptides. Early onset familial Alzheimer disease mutations in presenilin (PS), the catalytic core of gamma-secretase, invariably increase the Abeta42:Abeta40 ratio. However, the mechanism by which these mutations affect gamma-secretase complex formation and cleavage specificity is poorly understood. We show that our in vitro assay system recapitulates the effect of PS1 mutations on the Abeta42:Abeta40 ratio observed in cell and animal models. We have developed a series of small molecule affinity probes that allow us to characterize active gamma-secretase complexes. Furthermore we reveal that the equilibrium of PS1- and PS2-containing active complexes is dynamic and altered by overexpression of Pen2 or PS1 mutants and that formation of PS2 complexes is positively correlated with increased Abeta42:Abeta40 ratios. These data suggest that perturbations to gamma-secretase complex equilibrium can have a profound effect on enzyme activity and that increased PS2 complexes along with mutated PS1 complexes contribute to an increased Abeta42:Abeta40 ratio.
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Affiliation(s)
- Lisa Placanica
- Molecular Pharmacology and Chemistry Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065; Department of Pharmacology, Weill Graduate School of Medical Science of Cornell University, New York, New York 10065
| | - Leonid Tarassishin
- Molecular Pharmacology and Chemistry Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Guangli Yang
- Molecular Pharmacology and Chemistry Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Erica Peethumnongsin
- Huffington Center on Aging, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
| | - Seong-Hun Kim
- The Center for Molecular Neurobiology, The University of Chicago, Chicago, Illinois 60637
| | - Hui Zheng
- Huffington Center on Aging, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
| | - Sangram S Sisodia
- The Center for Molecular Neurobiology, The University of Chicago, Chicago, Illinois 60637
| | - Yue-Ming Li
- Molecular Pharmacology and Chemistry Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065; Department of Pharmacology, Weill Graduate School of Medical Science of Cornell University, New York, New York 10065.
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43
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Structure and function of gamma-secretase. Semin Cell Dev Biol 2008; 20:211-8. [PMID: 19007897 DOI: 10.1016/j.semcdb.2008.10.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Accepted: 10/13/2008] [Indexed: 11/22/2022]
Abstract
The gamma-secretase complex is a prime target for pharmacological intervention in Alzheimer's disease and so far drug discovery efforts have yielded a large variety of potent and rather specific inhibitors of this enzymatic activity. However, as gamma-secretase is able to cleave a wide variety of physiological important substrates, the real challenge is to develop substrate-specific compounds. Therefore, obtaining structural information about gamma-secretase is indispensable. As crystal structures of the complex will be difficult to achieve, applied biochemical approaches need to be integrated with structural information obtained from other intramembrane-cleaving proteases. Here we review current knowledge about the structure and function of gamma-secretase and discuss the value of these findings for the mechanistic understanding of this unusual protease.
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44
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Steiner H, Winkler E, Haass C. Chemical cross-linking provides a model of the gamma-secretase complex subunit architecture and evidence for close proximity of the C-terminal fragment of presenilin with APH-1. J Biol Chem 2008; 283:34677-86. [PMID: 18801744 DOI: 10.1074/jbc.m709067200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gamma-secretase is an intramembrane cleaving aspartyl protease complex intimately implicated in Alzheimer disease pathogenesis. The protease is composed of the catalytic subunit presenilin (PS1 or PS2), the substrate receptor nicastrin (NCT), and two additional subunits, APH-1 (APH-1a, as long and short splice forms (APH-1aL, APH-1aS), or APH-1b) and PEN-2. Apart from the Alzheimer disease-associated beta-amyloid precursor protein, gamma-secretase has been shown to cleave a large number of other type I membrane proteins. Despite the progress in elucidating gamma-secretase function, basic questions concerning the precise organization of its subunits, their molecular interactions, and their exact stoichiometry in the complex are largely unresolved. Here we isolated endogenous human gamma-secretase from human embryonic kidney 293 cells and investigated the subunit architecture of the gamma-secretase complex formed by PS1, NCT, APH-1aL, and PEN-2 by chemical cross-linking. Using this approach, we provide evidence for the close neighborhood of the PS1 N- and C-terminal fragments (NTF and CTF, respectively), the PS1 NTF and PEN-2, the PS1 CTF and APH-1aL, and NCT and APH-1aL. We thus identify a previously unrecognized PS1 CTF/APH-1aL interaction, verify subunit interactions deduced previously from indirect approaches, and provide a model of the gamma-secretase complex subunit architecture. Finally, we further show that, like the PS1 CTF, the PS2 CTF also interacts with APH-1aL, and we provide evidence that these interactions also occur with the other APH-1 variants, suggesting similar subunit architectures of all gamma-secretase complexes.
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Affiliation(s)
- Harald Steiner
- Center for Integrated Protein Science Munich and Adolf-Butenandt-Institute, Department of Biochemistry, Laboratory for Neurodegenerative Disease Research, Ludwig-Maximilians-University, 80336 Munich, Germany.
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45
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Spasic D, Annaert W. Building gamma-secretase: the bits and pieces. J Cell Sci 2008; 121:413-20. [PMID: 18256384 DOI: 10.1242/jcs.015255] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
gamma-Secretase is a promiscuous aspartyl protease responsible for the final intramembrane cleavage of various type I transmembrane proteins after their large ectodomains are shed. The vast functional diversity of its substrates, which are involved in cell fate decisions, adhesion, neurite outgrowth and synapse formation, highlights the important role gamma-secretase plays in development and neurogenesis. The most renowned substrates are the amyloid precursor protein and Notch, from which gamma-secretase liberates amyloid beta peptides and induces downstream signalling, respectively. gamma-Secretase is a multiprotein complex containing presenilin (which harbours the catalytic site), nicastrin, APH1 and PEN2. Its assembly occurs under tight control of ER-Golgi recycling regulators, which allows defined quantities of complexes to reach post-Golgi compartments, where gamma-secretase activity is regulated by multiple other factors. 3D-EM rendering reveals a complex with a translucent inner space, suggesting the presence of a water-filled cavity required for intramembrane proteolysis. Despite huge efforts, we are now only beginning to unravel the assembly, stoichiometry, activation and subcellular location of gamma-secretase.
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Affiliation(s)
- Dragana Spasic
- Laboratory for Membrane Trafficking, Center for Human Genetics (KULeuven) and Department of Molecular and Developmental Genetics (VIB), O&N1, Gasthuisberg, Herestraat 49, Leuven, Belgium
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46
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Tolia A, Horré K, De Strooper B. Transmembrane domain 9 of presenilin determines the dynamic conformation of the catalytic site of gamma-secretase. J Biol Chem 2008; 283:19793-803. [PMID: 18482978 DOI: 10.1074/jbc.m802461200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
One of the most prominent drug targets for the treatment of Alzheimer disease is gamma-secretase, a multi-protein complex responsible for the generation of the amyloid-beta peptide. The catalytic core of the complex lies on presenilin, a multi-spanning membrane protease, the activity of which depends on two aspartate residues located in transmembrane domains 6 and 7. We have recently shown by cysteine-scanning mutagenesis that these aspartates are facing a water-filled cavity in the lipid bilayer, demonstrating how proteolytic cleavage of the substrates can be taking place within the membrane. Here, we demonstrate that transmembrane domain 9 and hydrophobic domain VII in the large cytoplasmic loop of presenilin are dynamic structural parts of this cavity. Hydrophobic domain VII is associated with transmembrane domain 7 in the membrane, probably facilitating the entrance of water molecules in the catalytic site. Transmembrane domain 9, on the other hand, exhibits a highly flexible structure, potentially involved in the transport of substrates to the catalytic site, as well as in the binding of gamma-secretase inhibitors. The conserved proline-alanine-leucine motif at the cytoplasmic part of this domain is extremely close to the catalytic Asp257 and is crucial for conformational changes leading to the activation of the catalytic site. We, also, identify a unique mutant in this domain (I437C) that specifically blocks amyloid-beta peptide production without affecting the processing of the physiologically indispensable Notch substrate. Our data are finally combined to propose a model for the architectural organization and activation of the catalytic site of presenilin.
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Affiliation(s)
- Alexandra Tolia
- Department for Molecular and Developmental Genetics, VIB (Vlaams Instituut voor Biotechnologie), Belgium
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47
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Abstract
Gamma-Secretase is a promiscuous protease that cleaves bitopic membrane proteins within the lipid bilayer. Elucidating both the mechanistic basis of gamma-secretase proteolysis and the precise factors regulating substrate identification is important because modulation of this biochemical degradative process can have important consequences in a physiological and pathophysiological context. Here, we briefly review such information for all major classes of intramembranously cleaving proteases (I-CLiPs), with an emphasis on gamma-secretase, an I-CLiP closely linked to the etiology of Alzheimer's disease. A large body of emerging data allows us to survey the substrates of gamma-secretase to ascertain the conformational features that predispose a peptide to cleavage by this enigmatic protease. Because substrate specificity in vivo is closely linked to the relative subcellular compartmentalization of gamma-secretase and its substrates, we also survey the voluminous body of literature concerning the traffic of gamma-secretase and its most prominent substrate, the amyloid precursor protein.
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Affiliation(s)
- A. J. Beel
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine, Rm. 5142 MRBIII, 21st Ave. S., Nashville, Tennessee 37232-8725 USA
| | - C. R. Sanders
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine, Rm. 5142 MRBIII, 21st Ave. S., Nashville, Tennessee 37232-8725 USA
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48
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Jozwiak K, Krzysko K, Bojarski L, Gacia M, Filipek S. Molecular Models of the Interface between Anterior Pharynx-Defective Protein 1 (APH-1) and Presenilin Involving GxxxG Motifs. ChemMedChem 2008; 3:627-34. [DOI: 10.1002/cmdc.200700189] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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49
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Kienlen-Campard P, Tasiaux B, Van Hees J, Li M, Huysseune S, Sato T, Fei JZ, Aimoto S, Courtoy PJ, Smith SO, Constantinescu SN, Octave JN. Amyloidogenic processing but not amyloid precursor protein (APP) intracellular C-terminal domain production requires a precisely oriented APP dimer assembled by transmembrane GXXXG motifs. J Biol Chem 2008; 283:7733-44. [PMID: 18201969 DOI: 10.1074/jbc.m707142200] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The beta-amyloid peptide (Abeta) is the major constituent of the amyloid core of senile plaques found in the brain of patients with Alzheimer disease. Abeta is produced by the sequential cleavage of the amyloid precursor protein (APP) by beta- and gamma-secretases. Cleavage of APP by gamma-secretase also generates the APP intracellular C-terminal domain (AICD) peptide, which might be involved in regulation of gene transcription. APP contains three Gly-XXX-Gly (GXXXG) motifs in its juxtamembrane and transmembrane (TM) regions. Such motifs are known to promote dimerization via close apposition of TM sequences. We demonstrate that pairwise replacement of glycines by leucines or isoleucines, but not alanines, in a GXXXG motif led to a drastic reduction of Abeta40 and Abeta42 secretion. beta-Cleavage of mutant APP was not inhibited, and reduction of Abeta secretion resulted from inhibition of gamma-cleavage. It was anticipated that decreased gamma-cleavage of mutant APP would result from inhibition of its dimerization. Surprisingly, mutations of the GXXXG motif actually enhanced dimerization of the APP C-terminal fragments, possibly via a different TM alpha-helical interface. Increased dimerization of the TM APP C-terminal domain did not affect AICD production.
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Affiliation(s)
- Pascal Kienlen-Campard
- Center for Neurosciences, Experimental Pharmacology Unit, Université Catholique de Louvain, B-1200 Brussels, Belgium
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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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