1
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Serneels L, Bammens L, Zwijsen A, Tolia A, Chávez-Gutiérrez L, De Strooper B. Functional and topological analysis of PSENEN, the fourth subunit of the γ-secretase complex. J Biol Chem 2024; 300:105533. [PMID: 38072061 PMCID: PMC10790097 DOI: 10.1016/j.jbc.2023.105533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/20/2023] [Accepted: 11/26/2023] [Indexed: 01/01/2024] Open
Abstract
The γ-secretase complexes are intramembrane cleaving proteases involved in the generation of the Aβ peptides in Alzheimer's disease. The complex consists of four subunits, with Presenilin harboring the catalytic site. Here, we study the role of the smallest subunit, PSENEN or Presenilin enhancer 2, encoded by the gene Psenen, in vivo and in vitro. We find a profound Notch deficiency phenotype in Psenen-/- embryos confirming the essential role of PSENEN in the γ-secretase complex. We used Psenen-/- fibroblasts to explore the structure-function of PSENEN by the scanning cysteine accessibility method. Glycine 22 and proline 27, which border the membrane domains 1 and 2 of PSENEN, are involved in complex formation and stabilization of γ-secretase. The hairpin structured hydrophobic membrane domains 1 and 2 are exposed to a water-containing cavity in the complex, while transmembrane domain 3 is not water exposed. We finally demonstrate the essential role of PSENEN for the cleavage activity of the complex. PSENEN is more than a structural component of the γ-secretase complex and might contribute to the catalytic mechanism of the enzyme.
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Affiliation(s)
- Lutgarde Serneels
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Leen Bammens
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - An Zwijsen
- Laboratory of Developmental Signaling, Center for Human Genetics, KU Leuven, Leuven, Belgium
| | - Alexandra Tolia
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Lucía Chávez-Gutiérrez
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Bart De Strooper
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, VIB, Leuven, Belgium; Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven, Belgium.
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2
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Song C, Zhang J, Xu C, Gao M, Li N, Geng Q. The critical role of γ-secretase and its inhibitors in cancer and cancer therapeutics. Int J Biol Sci 2023; 19:5089-5103. [PMID: 37928268 PMCID: PMC10620818 DOI: 10.7150/ijbs.87334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 07/22/2023] [Indexed: 11/07/2023] Open
Abstract
As a multi-substrate transmembrane protease, γ-secretase exists widely in various cells. It controls multiple important cellular activities through substrate cleavage. γ-secretase inhibitors (GSIs) play a role in cancer inhibition by blocking Notch cleavage, and are considered as potential therapeutic strategies for cancer. Currently, GSIs have encouraging performance in preclinical models, yet this success does not translate well in clinical trials. In recent years, a number of breakthrough discoveries have shown us the promise of targeting γ-secretase for the treatment of cancer. Here, we integrate a large amount of data from γ-secretase and its inhibitors and cancer in nearly 30 years, comb and discuss the close connection between γ-secretase and cancer, as well as the potential and problems of current GSIs in cancer treatment. We analyze the possible reasons for the failure performance of current GSIs in clinical trials, and make recommendations for future research areas.
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Affiliation(s)
- Congkuan Song
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jinjin Zhang
- Department of Emergency, Taihe Hospital, Shiyan, China
| | - Chenzhen Xu
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Minglang Gao
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Ning Li
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Qing Geng
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, China
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Zhao Y, Zhou H, Zhao Y, Liang Z, Gong X, Yu J, Huang T, Yang C, Wu M, Xiao Y, Yang Y, Liu W, Wang X, Shu X, Bao J. BACE1 SUMOylation deregulates phosphorylation and ubiquitination in Alzheimer's disease pathology. J Neurochem 2023; 166:318-327. [PMID: 37286480 DOI: 10.1111/jnc.15870] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 05/10/2023] [Accepted: 05/15/2023] [Indexed: 06/09/2023]
Abstract
BACE1 is essential for the generation of amyloid-β (Aβ) that likely initiates the toxicity in Alzheimer's disease (AD). BACE1 activity is mainly regulated by post-translational modifications, but the relationship between these modifications is not fully characterized. Here, we studied the effects of BACE1 SUMOylation on its phosphorylation and ubiquitination. We demonstrate that SUMOylation of BACE1 inhibits its phosphorylation at S498 and its ubiquitination in vitro. Conversely, BACE1 phosphorylation at S498 suppresses its SUMOylation, which results in promoting BACE1 degradation in vitro. Furthermore, an increase in BACE1 SUMOylation is associated with the progression of AD pathology, while its phosphorylation and ubiquitination are decreased in an AD mouse model. Our findings suggest that BACE1 SUMOylation reciprocally influences its phosphorylation and competes against its ubiquitination, which might provide a new insight into the regulations of BACE1 activity and Aβ accumulation.
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Affiliation(s)
- Yanna Zhao
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan, China
- Department of Pathology and Pathophysiology, School of Medicine, Jianghan University, Wuhan, China
| | - Hongyan Zhou
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan, China
- Department of Pathology and Pathophysiology, School of Medicine, Jianghan University, Wuhan, China
| | - Yan Zhao
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan, China
| | - Zhen Liang
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan, China
| | - Xiaokang Gong
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan, China
| | - Jing Yu
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan, China
- Department of Pathology and Pathophysiology, School of Medicine, Jianghan University, Wuhan, China
| | - Tiantian Huang
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan, China
- Department of Pathology and Pathophysiology, School of Medicine, Jianghan University, Wuhan, China
| | - Chaoqin Yang
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan, China
- Department of Pathology and Pathophysiology, School of Medicine, Jianghan University, Wuhan, China
| | - Mengjuan Wu
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan, China
- Department of Pathology and Pathophysiology, School of Medicine, Jianghan University, Wuhan, China
| | - Yifan Xiao
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan, China
- Department of Pathology and Pathophysiology, School of Medicine, Jianghan University, Wuhan, China
| | - Youhua Yang
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan, China
- Department of Physiology, School of Medicine, Jianghan University, Wuhan, China
| | - Wei Liu
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan, China
- Department of Pathology and Pathophysiology, School of Medicine, Jianghan University, Wuhan, China
| | - Xiaochuan Wang
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan, China
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiji Shu
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan, China
- Department of Pathology and Pathophysiology, School of Medicine, Jianghan University, Wuhan, China
| | - Jian Bao
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan, China
- Department of Pathology and Pathophysiology, School of Medicine, Jianghan University, Wuhan, China
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Bao J, Liang Z, Gong X, Zhao Y, Wu M, Liu W, Tu C, Wang X, Shu X. Tangeretin Inhibits BACE1 Activity and Attenuates Cognitive Impairments in AD Model Mice. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:1536-1546. [PMID: 35084179 DOI: 10.1021/acs.jafc.1c07241] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Tangeretin (TAN) exhibits many bioactivities, including neuroprotective effects. However, the efficacy of TAN in Alzheimer's disease (AD) has not been sufficiently investigated. In the present study, we integrated behavioral tests, pathology assessment, and biochemical analyses to elucidate the antidementia activity of TAN in APPswe/PSEN1dE9 transgenic (Tg) mice. At supplementation levels of 100 mg/kg body weight per day, TAN significantly attenuated the cognitive impairment of Tg mice in behavioral tests. These effects were associated with less synaptic impairments and fewer β-amyloid accumulations after TAN administration. Furthermore, our study revealed that TAN possessed powerful inhibitory activity against β-secretase both in vitro and in vivo, which played a crucial role in the process of Aβ generation. These findings indicate that TAN is a potential drug for preventing AD pathology. The key mechanism underlying the antidementia effect of TAN may include its inhibitory activity against β-secretase.
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Affiliation(s)
- Jian Bao
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, China; Department of Pathology and Pathophysiology, School of Medicine, Jianghan University, Wuhan 430056, China
| | - Zheng Liang
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan 430056, China
| | - Xiaokang Gong
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan 430056, China
| | - Yanna Zhao
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, China; Department of Pathology and Pathophysiology, School of Medicine, Jianghan University, Wuhan 430056, China
| | - Mengjuan Wu
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, China; Department of Pathology and Pathophysiology, School of Medicine, Jianghan University, Wuhan 430056, China
| | - Wei Liu
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, China; Department of Pathology and Pathophysiology, School of Medicine, Jianghan University, Wuhan 430056, China
| | - Chenyu Tu
- School of Medicine, Jianghan University, Wuhan 430056, China
| | - Xiaochuan Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiji Shu
- Institutes of Biomedical Sciences, School of Medicine, Jianghan University, China; Department of Pathology and Pathophysiology, School of Medicine, Jianghan University, Wuhan 430056, China
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Zhou P, Liu J, Xu T, Guo Y, Han Y, He Y, Lin L, Xiao X. Mutations in γ-secretase subunit-encoding PSENEN gene alone may not be sufficient for the development of acne inversa. J Dermatol Sci 2021; 103:73-81. [PMID: 34330582 DOI: 10.1016/j.jdermsci.2021.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/11/2021] [Accepted: 06/16/2021] [Indexed: 12/21/2022]
Abstract
BACKGROUND The effects of PSENEN mutations in patients with acne inversa (AI) are poorly understood. Hyperproliferation of follicular keratinocytes and resulting occlusion may constitute the initial pathophysiology. OBJECTIVE To investigate the effects of PSENEN knockdown on γ-secretase subunits, biological behaviors, and related signaling pathways in keratinocytes. METHODS HaCaT cells were divided into an experimental group (PSENEN knock down), a negative control group, and a blank control group. Whole transcriptome sequencing was used to measure differences in mRNA expression of the whole genome; real-time PCR and Western blotting were performed to determine the interference efficiency and the effects of interference on the components of γ-secretase and related molecules. CCK-8 was used to measure cell proliferation, and flow cytometry was used to measure apoptosis and the cell cycle. RESULTS A comparison of five healthy controls with three patients with PSENEN mutation (c.66delG, c.279delC, c.229_230insCACC) revealed decreased expression of mRNA and protein in skin lesions of the experimental group. In this group, expression of the other components of γ-secretase presenilin C-terminal fragment decreased, expression of immature nicastrin increased, expression of mature nicastrin decreased, and expression of anterior pharynx defective-1 remained unchanged. KEGG analysis revealed that differentially expressed molecules were enriched in m-TOR signaling pathways. Subsequent verification confirmed that differences in PI3K-AKT-mTOR signaling pathway molecules, cell proliferation, apoptosis, cell cycle and the expression levels of Ki-67, KRT1, and IVL between the groups were not statistically significant. CONCLUSIONS PSENEN mutations alone may be insufficient to cause the development of AI, or they may only induce a mild phenotype of AI.
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Affiliation(s)
- Pengjun Zhou
- Department of Dermatology, The Union Hospital, Fujian Medical University, Fujian, China; Department of Dermatology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, China
| | - Jingjing Liu
- Department of Dermatology, The Union Hospital, Fujian Medical University, Fujian, China
| | - Tianxing Xu
- Department of Dermatology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, China
| | - Yanni Guo
- Department of Dermatology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, China
| | - Yue Han
- Department of Dermatology, The Union Hospital, Fujian Medical University, Fujian, China
| | - Yanyan He
- Institute of Dermatology, Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Chinese Academy of Medical Sciences and Peking Union Medical College, Jiangsu, China
| | - Lihang Lin
- Department of Dermatology, The Union Hospital, Fujian Medical University, Fujian, China.
| | - Xuemin Xiao
- Department of Dermatology, The Union Hospital, Fujian Medical University, Fujian, China.
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6
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Cai T, Tomita T. Structure-activity relationship of presenilin in γ-secretase-mediated intramembrane cleavage. Semin Cell Dev Biol 2020; 105:102-109. [PMID: 32171519 DOI: 10.1016/j.semcdb.2020.02.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 01/12/2023]
Abstract
Genetic research on familial cases of Alzheimer disease have identified presenilin (PS) as an important membrane protein in the pathomechanism of this disease. PS is the catalytic subunit of γ-secretase, which is responsible for the generation of amyloid-β peptide deposited in the brains of Alzheimer disease patients. γ-Secretase is an atypical protease composed of four membrane proteins (i.e., presenilin, nicastrin, anterior pharynx defective-1 (Aph-1), and presenilin enhancer-2 (Pen-2)) and mediates intramembrane proteolysis. Numerous investigations have been conducted toward understanding the structural features of γ-secretase components as well as the cleavage mechanism of γ-secretase. In this review, we summarize our current understanding of the structure and activity relationship of the γ-secretase complex.
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Affiliation(s)
- Tetsuo Cai
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Taisuke Tomita
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, 113-0033, Japan.
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7
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Wolfe MS. Unraveling the complexity of γ-secretase. Semin Cell Dev Biol 2020; 105:3-11. [PMID: 31980377 PMCID: PMC7371508 DOI: 10.1016/j.semcdb.2020.01.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/26/2019] [Accepted: 01/15/2020] [Indexed: 01/07/2023]
Abstract
γ-Secretase was initially defined as a proteolytic activity that cleaves within the transmembrane of the amyloid precursor protein (APP) to produce the amyloid β-peptide of Alzheimer's disease. The discovery of mutations in APP and the presenilins associated with familial Alzheimer's disease and their effects on APP processing dovetailed with pharmacological studies on γ-secretase, leading to the revelation that presenilins are unprecedented membrane-embedded aspartyl proteases. Other members of what became known as the γ-secretase complex were subsequently identified. In parallel with these advances, connections between presenilins and Notch receptors essential to metazoan development became evident, resulting in the concurrent realization that γ-secretase also carries out intramembrane proteolysis of Notch as part of its signaling mechanism. Substantial progress has been made toward elucidating how γ-secretase carries out complex processing of transmembrane domains, how it goes awry in familial Alzheimer's disease, the scope of its substrates, and the atomic details of its structure. Critical questions remain for future study, toward further unraveling the complexity of this unique membrane-embedded proteolytic machine and its roles in biology and disease.
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Affiliation(s)
- Michael S Wolfe
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66045, USA.
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8
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Steiner H, Fukumori A, Tagami S, Okochi M. Making the final cut: pathogenic amyloid-β peptide generation by γ-secretase. Cell Stress 2018; 2:292-310. [PMID: 31225454 PMCID: PMC6551803 DOI: 10.15698/cst2018.11.162] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Alzheimer´s disease (AD) is a devastating neurodegenerative disease of the elderly population. Genetic evidence strongly suggests that aberrant generation and/or clearance of the neurotoxic amyloid-β peptide (Aβ) is triggering the disease. Aβ is generated from the amyloid precursor protein (APP) by the sequential cleavages of β- and γ-secretase. The latter cleavage by γ-secretase, a unique and fascinating four-component protease complex, occurs in the APP transmembrane domain thereby releasing Aβ species of 37-43 amino acids in length including the longer, highly pathogenic peptides Aβ42 and Aβ43. The lack of a precise understanding of Aβ generation as well as of the functions of other γ-secretase substrates has been one factor underlying the disappointing failure of γ-secretase inhibitors in clinical trials, but on the other side also been a major driving force for structural and in depth mechanistic studies on this key AD drug target in the past few years. Here we review recent breakthroughs in our understanding of how the γ-secretase complex recognizes substrates, of how it binds and processes β-secretase cleaved APP into different Aβ species, as well as the progress made on a question of outstanding interest, namely how clinical AD mutations in the catalytic subunit presenilin and the γ-secretase cleavage region of APP lead to relative increases of Aβ42/43. Finally, we discuss how the knowledge emerging from these studies could be used to therapeutically target this enzyme in a safe way.
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Affiliation(s)
- Harald Steiner
- Biomedical Center (BMC), Metabolic Biochemistry, Ludwig-Maximilians-University Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Akio Fukumori
- Department of Aging Neurobiology, National Center for Geriatrics and Gerontology, Obu & Department of Mental Health Promotion, Osaka University Graduate School of Medicine, Toyonaka, Japan
| | - Shinji Tagami
- Neuropsychiatry, Department of Integrated Medicine, Division of Internal Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Masayasu Okochi
- Neuropsychiatry, Department of Integrated Medicine, Division of Internal Medicine, Osaka University Graduate School of Medicine, Suita, Japan
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9
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Johnson DS, Li YM, Pettersson M, St George-Hyslop PH. Structural and Chemical Biology of Presenilin Complexes. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a024067. [PMID: 28320827 PMCID: PMC5710098 DOI: 10.1101/cshperspect.a024067] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The presenilin proteins are the catalytic subunits of a tetrameric complex containing presenilin 1 or 2, anterior pharynx defective 1 (APH1), nicastrin, and PEN-2. Other components such as TMP21 may exist in a subset of specialized complexes. The presenilin complex is the founding member of a unique class of aspartyl proteases that catalyze the γ, ɛ, ζ site cleavage of the transmembrane domains of Type I membrane proteins including amyloid precursor protein (APP) and Notch. Here, we detail the structural and chemical biology of this unusual enzyme. Taken together, these studies suggest that the complex exists in several conformations, and subtle long-range (allosteric) shifts in the conformation of the complex underpin substrate access to the catalytic site and the mechanism of action for allosteric inhibitors and modulators. Understanding the mechanics of these shifts will facilitate the design of γ-secretase modulator (GSM) compounds that modulate the relative efficiency of γ, ɛ, ζ site cleavage and/or substrate specificity.
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Affiliation(s)
- Douglas S. Johnson
- Pfizer Worldwide Research and Development, Cambridge, Massachusetts 02139
| | - Yue-Ming Li
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Martin Pettersson
- Pfizer Worldwide Research and Development, Cambridge, Massachusetts 02139
| | - Peter H. St George-Hyslop
- Cambridge Institute for Medical Research, Wellcome Trust MRC Building, Addenbrookes Hospital, Cambridge CB2 0XY, United Kingdom,Tanz Centre for Research in Neurodegenerative Diseases and Departments of Medicine, Laboratory Medicine and Pathobiology, and Medical Biophysics, University of Toronto, Toronto, Ontario M5T 2S8, Canada
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10
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Aguayo-Ortiz R, Chávez-García C, Straub JE, Dominguez L. Characterizing the structural ensemble of γ-secretase using a multiscale molecular dynamics approach. Chem Sci 2017; 8:5576-5584. [PMID: 28970936 PMCID: PMC5618787 DOI: 10.1039/c7sc00980a] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 06/05/2017] [Indexed: 11/21/2022] Open
Abstract
γ-Secretase is an intramembrane-cleaving aspartyl protease that plays an essential role in the processing of a variety of integral membrane proteins. Its role in the ultimate cleavage step in the processing of amyloid precursor protein to form amyloid-β (Aβ) peptide makes it an important therapeutic target in Alzheimer's disease research. Significant recent advances have been made in structural studies of this critical membrane protein complex. However, details of the mechanism of activation of the enzyme complex remain unclear. Using a multiscale computational modeling approach, combining multiple coarse-grained microsecond dynamic trajectories with all-atom models, the structure and two conformational states of the γ-secretase complex were evaluated. The transition between enzymatic state 1 and state 2 is shown to critically depend on the protonation states of the key catalytic residues Asp257 and Asp385 in the active site domain. The active site formation, related to our γ-secretase state 2, is observed to involve a concerted movement of four transmembrane helices from the catalytic subunit, resulting in the required localization of the catalytic residues. Global analysis of the structural ensemble of the enzyme complex was used to identify collective fluctuations important to the mechanism of substrate recognition and demonstrate that the corresponding fluctuations observed were uncorrelated with structural changes associated with enzyme activation. Overall, this computational study provides essential insight into the role of structure and dynamics in the activation and function of γ-secretase.
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Affiliation(s)
- Rodrigo Aguayo-Ortiz
- Departamento de Fisicoquímica , Facultad de Química , Universidad Nacional Autónoma de México , Mexico City , 04510 , Mexico .
| | - Cecilia Chávez-García
- Departamento de Fisicoquímica , Facultad de Química , Universidad Nacional Autónoma de México , Mexico City , 04510 , Mexico .
| | - John E Straub
- Department of Chemistry , Boston University , Boston , Massachusetts 02215 , USA
| | - Laura Dominguez
- Departamento de Fisicoquímica , Facultad de Química , Universidad Nacional Autónoma de México , Mexico City , 04510 , Mexico .
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11
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Abstract
γ-secretase, a membrane-embedded aspartate protease, catalyzes peptide bond hydrolysis of a large variety of type I integral membrane proteins exemplified by amyloid precursor protein (APP). Cleavage of APP leads to formation of β-amyloid plaque, which is a hallmark of Alzheimer's disease (AD). Over 200 AD-associated mutations are mapped to presenilin 1 (PS1), the catalytic component of γ-secretase. In the past three years, several cryo-electron microscopy (cryo-EM) structures of human γ-secretase have been determined at near atomic resolutions. Here we summarize the methods involved and discuss structural features of γ-secretase and the associated functional insights.
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Affiliation(s)
- Guanghui Yang
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
| | - Rui Zhou
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
| | - Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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12
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Affiliation(s)
- Rodrigo Aguayo-Ortiz
- Departamento de Fisicoquímica; Universidad Nacional Autónoma de México; Ciudad de México 04510 México
| | - Laura Dominguez
- Departamento de Fisicoquímica; Universidad Nacional Autónoma de México; Ciudad de México 04510 México
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13
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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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Li Y, Sun H, Chen Z, Xu H, Bu G, Zheng H. Implications of GABAergic Neurotransmission in Alzheimer's Disease. Front Aging Neurosci 2016; 8:31. [PMID: 26941642 PMCID: PMC4763334 DOI: 10.3389/fnagi.2016.00031] [Citation(s) in RCA: 163] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 02/08/2016] [Indexed: 01/02/2023] Open
Abstract
Alzheimer's disease (AD) is characterized pathologically by the deposition of β-amyloid peptides (Aβ) and the accumulation of neurofibrillary tangles (NFTs) composed of hyper-phosphorylated tau. Regardless of the pathological hallmarks, synaptic dysfunction is widely accepted as a causal event in AD. Of the two major types of synapses in the central nervous system (CNS): glutamatergic and GABAergic, which provide excitatory and inhibitory outputs respectively, abundant data implicate an impaired glutamatergic system during disease progression. However, emerging evidence supports the notion that disrupted default neuronal network underlies impaired memory, and that alterations of GABAergic circuits, either plays a primary role or as a compensatory response to excitotoxicity, may also contribute to AD by disrupting the overall network function. The goal of this review is to provide an overview of the involvement of Aβ, tau and apolipoprotein E4 (apoE4), the major genetic risk factor in late-onset AD (LOAD), in GABAergic neurotransmission and the potential of modulating the GABAergic function as AD therapy.
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Affiliation(s)
- Yanfang Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University Xiamen, China
| | - Hao Sun
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University Xiamen, China
| | - Zhicai Chen
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University Xiamen, China
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen UniversityXiamen, China; Neurodegenerative Disease Research Program, Sanford-Burnham Medical Research InstituteLa Jolla, CA, USA
| | - Guojun Bu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen UniversityXiamen, China; Department of Neuroscience, Mayo ClinicJacksonville, FL, USA
| | - Hui Zheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen UniversityXiamen, China; The Interdepartmental Program of Translational Biology and Molecular Medicine, Huffington Center on Aging, Baylor College of MedicineHouston, TX, USA
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