1
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Kurth V, Ogorek I, Münch C, Lopez-Rios J, Ousson S, Lehmann S, Nieweg K, Roebroek AJM, Pietrzik CU, Beher D, Weggen S. Pathogenic Aβ production by heterozygous PSEN1 mutations is intrinsic to the mutant protein and not mediated by conformational hindrance of wild-type PSEN1. J Biol Chem 2023; 299:104997. [PMID: 37394008 PMCID: PMC10413157 DOI: 10.1016/j.jbc.2023.104997] [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: 10/13/2022] [Revised: 05/30/2023] [Accepted: 06/07/2023] [Indexed: 07/04/2023] Open
Abstract
Presenilin-1 (PSEN1) is the catalytic subunit of the intramembrane protease γ-secretase and undergoes endoproteolysis during its maturation. Heterozygous mutations in the PSEN1 gene cause early-onset familial Alzheimer's disease (eFAD) and increase the proportion of longer aggregation-prone amyloid-β peptides (Aβ42 and/or Aβ43). Previous studies had suggested that PSEN1 mutants might act in a dominant-negative fashion by functional impediment of wild-type PSEN1, but the exact mechanism by which PSEN1 mutants promote pathogenic Aβ production remains controversial. Using dual recombinase-mediated cassette exchange (dRMCE), here we generated a panel of isogenic embryonic and neural stem cell lines with heterozygous, endogenous expression of PSEN1 mutations. When catalytically inactive PSEN1 was expressed alongside the wild-type protein, we found the mutant accumulated as a full-length protein, indicating that endoproteolytic cleavage occurred strictly as an intramolecular event. Heterozygous expression of eFAD-causing PSEN1 mutants increased the Aβ42/Aβ40 ratio. In contrast, catalytically inactive PSEN1 mutants were still incorporated into the γ-secretase complex but failed to change the Aβ42/Aβ40 ratio. Finally, interaction and enzyme activity assays demonstrated the binding of mutant PSEN1 to other γ-secretase subunits, but no interaction between mutant and wild-type PSEN1 was observed. These results establish that pathogenic Aβ production is an intrinsic property of PSEN1 mutants and strongly argue against a dominant-negative effect in which PSEN1 mutants would compromise the catalytic activity of wild-type PSEN1 through conformational effects.
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Affiliation(s)
- Vanessa Kurth
- Department of Neuropathology, Heinrich Heine University, Düsseldorf, Germany
| | - Isabella Ogorek
- Department of Neuropathology, Heinrich Heine University, Düsseldorf, Germany; Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Carolina Münch
- Department of Neuropathology, Heinrich Heine University, Düsseldorf, Germany
| | - Javier Lopez-Rios
- Centro Andaluz de Biología del Desarrollo (CABD), CSIC-Universidad Pablo de Olavide-Junta de Andalucia, Sevilla, Spain
| | | | - Sandra Lehmann
- Department of Neuropathology, Heinrich Heine University, Düsseldorf, Germany
| | - Katja Nieweg
- Institute of Pharmacology and Clinical Pharmacy, Philipps-University, Marburg, Germany
| | | | - Claus U Pietrzik
- Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | | | - Sascha Weggen
- Department of Neuropathology, Heinrich Heine University, Düsseldorf, Germany.
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2
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Chen SY, Feilen LP, Chávez-Gutiérrez L, Steiner H, Zacharias M. Enzyme-substrate hybrid β-sheet controls geometry and water access to the γ-secretase active site. Commun Biol 2023; 6:670. [PMID: 37355752 PMCID: PMC10290658 DOI: 10.1038/s42003-023-05039-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 06/12/2023] [Indexed: 06/26/2023] Open
Abstract
γ-Secretase is an aspartyl intramembrane protease that cleaves the amyloid precursor protein (APP) involved in Alzheimer's disease pathology and other transmembrane proteins. Substrate-bound structures reveal a stable hybrid β-sheet immediately following the substrate scissile bond consisting of β1 and β2 from the enzyme and β3 from the substrate. Molecular dynamics simulations and enhanced sampling simulations demonstrate that the hybrid β-sheet stability is strongly correlated with the formation of a stable cleavage-compatible active geometry and it also controls water access to the active site. The hybrid β-sheet is only stable for substrates with 3 or more C-terminal residues beyond the scissile bond. The simulation model allowed us to predict the effect of Pro and Phe mutations that weaken the formation of the hybrid β-sheet which were confirmed by experimental testing. Our study provides a direct explanation why γ-secretase preferentially cleaves APP in steps of 3 residues and how the hybrid β-sheet facilitates γ-secretase proteolysis.
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Affiliation(s)
- Shu-Yu Chen
- Center of Functional Protein Assemblies, Technical University of Munich, Garching, Germany
| | - Lukas P Feilen
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Lucía Chávez-Gutiérrez
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium
- Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven, Leuven, Belgium
| | - Harald Steiner
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Biomedical Center (BMC), Division of Metabolic Biochemistry, Faculty of Medicine, LMU Munich, Germany
| | - Martin Zacharias
- Center of Functional Protein Assemblies, Technical University of Munich, Garching, Germany.
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3
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Schmidt FC, Fitz K, Feilen LP, Okochi M, Steiner H, Langosch D. Different transmembrane domains determine the specificity and efficiency of the cleavage activity of the γ-secretase subunit presenilin. J Biol Chem 2023; 299:104626. [PMID: 36944398 PMCID: PMC10164903 DOI: 10.1016/j.jbc.2023.104626] [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: 12/09/2022] [Revised: 03/07/2023] [Accepted: 03/11/2023] [Indexed: 03/23/2023] Open
Abstract
The γ-secretase complex catalyzes the intramembrane cleavage of C99, a carboxy-terminal fragment of the amyloid precursor protein. Two paralogs of its catalytic subunit presenilin (PS1 and PS2) are expressed which are autocatalytically cleaved into an N-terminal and a C-terminal fragment during maturation of γ-secretase. In this study, we compared the efficiency and specificity of C99 cleavage by PS1- and PS2-containing γ-secretases. Mass spectrometric analysis of cleavage products obtained in cell-free and cell-based assays revealed that the previously described lower amyloid-β (Aβ)38 generation by PS2 is accompanied by a reciprocal increase in Aβ37 production. We further found PS1 and PS2 to show different preferences in the choice of the initial cleavage site of C99. However, the differences in Aβ38 and Aβ37 generation appear to mainly result from altered subsequent stepwise cleavage of Aβ peptides. Apart from these differences in cleavage specificity, we confirmed a lower efficiency of initial C99 cleavage by PS2 using a detergent-solubilized γ-secretase system. By investigating chimeric PS1/2 molecules, we show that the membrane-embedded, nonconserved residues of the N-terminal fragment mainly account for the differential cleavage efficiency and specificity of both presenilins. At the level of individual transmembrane domains (TMDs), TMD3 was identified as a major modulator of initial cleavage site specificity. The efficiency of endoproteolysis strongly depends on nonconserved TMD6 residues at the interface to TMD2, i.e., at a putative gate of substrate entry. Taken together, our results highlight the role of individual presenilin TMDs in the cleavage of C99 and the generation of Aβ peptides.
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Affiliation(s)
- Fabian C Schmidt
- Biopolymer Chemistry, Technical University of Munich, Freising, Germany
| | - Katja Fitz
- Biopolymer Chemistry, Technical University of Munich, Freising, Germany
| | - Lukas P Feilen
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Masayasu Okochi
- Neuropsychiatry, Division of Internal Medicine, Department of Integrated Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Harald Steiner
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany; Division of Metabolic Biochemistry, Faculty of Medicine, Biomedical Center (BMC), Ludwig-Maximilians-University, Munich, Germany
| | - Dieter Langosch
- Biopolymer Chemistry, Technical University of Munich, Freising, Germany.
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4
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Guzmán-Ocampo DC, Aguayo-Ortiz R, Velasco-Bolom JL, Gupta PL, Roitberg AE, Dominguez L. Elucidating the Protonation State of the γ-Secretase Catalytic Dyad. ACS Chem Neurosci 2023; 14:261-269. [PMID: 36562727 DOI: 10.1021/acschemneuro.2c00563] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
γ-Secretase (GS) is an intramembrane aspartyl protease that participates in the sequential cleavage of C99 to generate different isoforms of the amyloid-β (Aβ) peptides that are associated with the development of Alzheimer's disease. Due to its importance in the proteolytic processing of C99 by GS, we performed pH replica exchange molecular dynamics (pH-REMD) simulations of GS in its apo and substrate-bound forms to sample the protonation states of the catalytic dyad. We found that the catalytic dyad is deprotonated at physiological pH in our apo form, but the presence of the substrate at the active site displaces its monoprotonated state toward physiological pH. Our results show that Asp257 acts as the general base and Asp385 as the general acid during the cleavage mechanism. We identified different amino acids such as Lys265, Arg269, and the PAL motif interacting with the catalytic dyad and promoting changes in its acid-base behavior. Finally, we also found a significant pKa shift of Glu280 related to the internalization of TM6-CT in the GS-apo form. Our study provides critical mechanistic insight into the GS mechanism and the basis for future research on the genesis of Aβ peptides and the development of Alzheimer's disease.
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Affiliation(s)
- Dulce C Guzmán-Ocampo
- Facultad de Química, Departamento de Fisicoquímica, Universidad Nacional Autónoma de México, Mexico City04510, Mexico
| | - Rodrigo Aguayo-Ortiz
- Facultad de Química, Departamento de Farmacia, Universidad Nacional Autónoma de México, Mexico City04510, Mexico
| | - José-Luis Velasco-Bolom
- Facultad de Química, Departamento de Fisicoquímica, Universidad Nacional Autónoma de México, Mexico City04510, Mexico
| | - Pancham Lal Gupta
- Department of Chemistry, University of Florida, Gainesville, Florida32611-7200, United States
| | - Adrian E Roitberg
- Department of Chemistry, University of Florida, Gainesville, Florida32611-7200, United States
| | - Laura Dominguez
- Facultad de Química, Departamento de Fisicoquímica, Universidad Nacional Autónoma de México, Mexico City04510, Mexico
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5
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6
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Ayton S, Bush AI. β-amyloid: The known unknowns. Ageing Res Rev 2021; 65:101212. [PMID: 33188924 DOI: 10.1016/j.arr.2020.101212] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 11/04/2020] [Accepted: 11/06/2020] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) stands out as a major disease without any form of preventative or disease modifying therapy. This is not for lack of trying. 33 phase 3 clinical trials of drugs targeting amyloid beta (Aβ) have failed to slow cognitive decline in AD. The field is at a cross-roads about whether to continue anti-Aβ therapy or more actively pursue alternative targets. With the burden of this disease to patients, families, and healthcare budgets growing yearly, the need for disease modifying AD therapies has become one of the highest priorities in all of medicine. While pathology, genetic and biochemical data offer a popular narrative for the causative role of Aβ, there are alternative explanations, and dissenting findings that, now more than ever, warrant thorough reanalysis. This review questions the major assumptions about Aβ on which therapies for AD were premised, and invites renewed interrogation into AD pathogenesis.
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Affiliation(s)
- Scott Ayton
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, 3052, Australia.
| | - Ashley I Bush
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, 3052, Australia.
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7
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Evolutionary History of Alzheimer Disease-Causing Protein Family Presenilins with Pathological Implications. J Mol Evol 2020; 88:674-688. [DOI: 10.1007/s00239-020-09966-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Accepted: 09/22/2020] [Indexed: 12/14/2022]
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8
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Substrate recruitment by γ-secretase. Semin Cell Dev Biol 2020; 105:54-63. [DOI: 10.1016/j.semcdb.2020.03.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 03/18/2020] [Accepted: 03/20/2020] [Indexed: 12/27/2022]
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9
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Kabir MT, Uddin MS, Setu JR, Ashraf GM, Bin-Jumah MN, Abdel-Daim MM. Exploring the Role of PSEN Mutations in the Pathogenesis of Alzheimer's Disease. Neurotox Res 2020; 38:833-849. [PMID: 32556937 DOI: 10.1007/s12640-020-00232-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/24/2020] [Accepted: 05/28/2020] [Indexed: 12/25/2022]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia. Mutations of presenilin (PSEN) genes that encode presenilin proteins have been found as the vital causal factors for early-onset familial AD (FAD). AD pathological features such as memory loss, synaptic dysfunction, and formation of plaques have been successfully mimicked in the transgenic mouse models that coexpress FAD-related presenilin and amyloid precursor protein (APP) variants. γ-Secretase (GS) is an enzyme that plays roles in catalyzing intramembranous APP proteolysis to release pathogenic amyloid beta (Aβ). It has been found that presenilins can play a role as the GS's catalytic subunit. FAD-related mutations in presenilins can modify the site of GS cleavage in a way that can elevate the production of longer and highly fibrillogenic Aβ. Presenilins can interact with β-catenin to generate presenilin complexes. Aforesaid interactions have also been studied to observe the mutational and physiological activities in the catenin signal transduction pathway. Along with APP, GS can catalyze intramembrane proteolysis of various substrates that play a vital role in synaptic function. PSEN mutations can cause FAD with autosomal dominant inheritance and early onset of the disease. In this article, we have reviewed the current progress in the analysis of PSENs and the correlation of PSEN mutations and AD pathogenesis.
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Affiliation(s)
| | - Md Sahab Uddin
- Department of Pharmacy, Southeast University, Dhaka, Bangladesh. .,Pharmakon Neuroscience Research Network, Dhaka, Bangladesh.
| | | | - Ghulam Md Ashraf
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - May N Bin-Jumah
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, Riyadh, 11474, Saudi Arabia
| | - Mohamed M Abdel-Daim
- Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia.,Pharmacology Department, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, 41522, Egypt
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10
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Chávez-Gutiérrez L, Szaruga M. Mechanisms of neurodegeneration - Insights from familial Alzheimer's disease. Semin Cell Dev Biol 2020; 105:75-85. [PMID: 32418657 DOI: 10.1016/j.semcdb.2020.03.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 03/13/2020] [Accepted: 03/16/2020] [Indexed: 12/18/2022]
Abstract
The rising prevalence of Alzheimer's disease (AD), together with the lack of effective treatments, portray it as one of the major health challenges of our times. Untangling AD implies advancing the knowledge of the biology that gets disrupted during the disease while deciphering the molecular and cellular mechanisms leading to AD-related neurodegeneration. In fact, a solid mechanistic understanding of the disease processes stands as an essential prerequisite for the development of safe and effective treatments. Genetics has provided invaluable clues to the genesis of the disease by revealing deterministic genes - Presenilins (PSENs) and the Amyloid Precursor Protein (APP) - that, when affected, lead in an autosomal dominant manner to early-onset, familial AD (FAD). PSEN is the catalytic subunit of the membrane-embedded γ-secretase complexes, which act as proteolytic switches regulating key cell signalling cascades. Importantly, these intramembrane proteases are responsible for the production of Amyloid β (Aβ) peptides from APP. The convergence of pathogenic mutations on one functional pathway, the amyloidogenic cleavage of APP, strongly supports the significance of this process in AD pathogenesis. Here, we review and discuss the state-of-the-art knowledge of the molecular mechanisms underlying FAD, their implications for the sporadic form of the disease and for the development of safe AD therapeutics.
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Affiliation(s)
- Lucía Chávez-Gutiérrez
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium; Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven, Leuven, Belgium.
| | - Maria Szaruga
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium; Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven, Leuven, Belgium
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11
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Zhang S, Cai F, Wu Y, Bozorgmehr T, Wang Z, Zhang S, Huang D, Guo J, Shen L, Rankin C, Tang B, Song W. A presenilin-1 mutation causes Alzheimer disease without affecting Notch signaling. Mol Psychiatry 2020; 25:603-613. [PMID: 29915376 DOI: 10.1038/s41380-018-0101-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 03/19/2018] [Accepted: 05/09/2018] [Indexed: 02/01/2023]
Abstract
Presenilin-1 (PSEN1) is the catalytic subunit of the γ-secretase complex, and pathogenic mutations in the PSEN1 gene account for the majority cases of familial AD (FAD). FAD-associated mutant PSEN1 proteins have been shown to affect APP processing and Aβ generation and inhibit Notch1 cleavage and Notch signaling. In this report, we found that a PSEN1 mutation (S169del) altered APP processing and Aβ generation, and promoted neuritic plaque formation as well as learning and memory deficits in AD model mice. However, this mutation did not affect Notch1 cleavage and Notch signaling in vitro and in vivo. Taken together, we demonstrated that PSEN1S169del has distinct effects on APP processing and Notch1 cleavage, suggesting that Notch signaling may not be critical for AD pathogenesis and serine169 could be a critical site as a potential target for the development of novel γ-secretase modulators without affecting Notch1 cleavage to treat AD.
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Affiliation(s)
- Shuting Zhang
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Fang Cai
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Yili Wu
- Department of Psychiatry, Graduate Program in Psychiatry, Jining Medical University, Jining, China
| | - Tahereh Bozorgmehr
- Department of Psychology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Zhe Wang
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Si Zhang
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Daochao Huang
- Chongqing City Key Lab of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Children's Hospital of Chongqing Medical University, 400014, Chongqing, China
| | - Jifeng Guo
- Department of Neurology, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lu Shen
- Department of Neurology, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Catharine Rankin
- Department of Psychology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Beisha Tang
- Department of Neurology, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Weihong Song
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada.
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12
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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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13
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Abstract
γ-Secretase is a membrane-embedded protease complex, with presenilin as the catalytic component containing two transmembrane aspartates in the active site. With more than 90 known substrates, the γ-secretase complex is considered "the proteasome of the membrane", with central roles in biology and medicine. The protease carries out hydrolysis within the lipid bilayer to cleave the transmembrane domain of the substrate multiple times before releasing secreted products. For many years, elucidation of γ-secretase structure and function largely relied on small-molecule probes and mutagenesis. Recently, however, advances in cryo-electron microscopy have led to the first detailed structures of the protease complex. Two new reports of structures of γ-secretase bound to membrane protein substrates provide great insight into the nature of substrate recognition and how Alzheimer's disease-causing mutations in presenilin might alter substrate binding and processing. These new structures offer a powerful platform for elucidating enzyme mechanisms, deciphering effects of disease-causing mutations, and advancing Alzheimer's disease drug discovery.
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Affiliation(s)
- Michael S Wolfe
- Department of Medicinal Chemistry , University of Kansas , Lawrence , Kansas 66045 , United States
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14
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Shen L, Qin W, Wu L, Zhou A, Tang Y, Wang Q, Jia L, Jia J. Two novel presenilin-1 mutations (I249L and P433S) in early onset Chinese Alzheimer's pedigrees and their functional characterization. Biochem Biophys Res Commun 2019; 516:264-269. [PMID: 31235249 DOI: 10.1016/j.bbrc.2019.05.185] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 05/30/2019] [Indexed: 01/02/2023]
Abstract
Clinical case study and functional characterization of the disease-associated presenilin-1 (PSEN1) mutations may help reveal the roles of PSEN1 in the pathogenesis of Alzheimer's disease (AD). By mutation screening of PSEN1, presenilin-2, and amyloid precursor protein genes in two Chinese Alzheimer's pedigrees, we identified two novel PSEN1 mutations, I249L and P433S. The two probands presented with progressive memory decline and subsequent psychiatric symptoms, with the age of onset at 54 and 34 years old, respectively. The effects of these two mutations on presenilin-1 endoproteolysis and β-amyloid (Aβ) production were examined in SH-SY5Y neuroblastoma cells infected with lentiviruses expressing presenilin-1 wild type (WT), I249L and P433S mutants. Both mutants showed increased Aβ42 levels and Aβ42/Aβ40 ratios. However, the I249L did not affect presenilin-1 endoproteolysis or Aβ43 production, whereas the P433S mutant inhibited presenilin-1 endoproteolysis and enhanced Aβ43 production. Our findings suggest that both I249L and P433S are pathogenic for early onset of AD by increasing Aβ42 production and Aβ42/Aβ40 ratios. Furthermore, P433S may contribute to the very early onset of AD by inhibiting PS1 endoproteolysis and enhancing the production of longer Aβ peptide Aβ43.
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Affiliation(s)
- Luxi Shen
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Wei Qin
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Liyong Wu
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Aihong Zhou
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Yi Tang
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Qi Wang
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Longfei Jia
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Jianping Jia
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China; Beijing Key Laboratory of Geriatric Cognitive Disorders, Beijing, 100053, PR China; Clinical Center for Neurodegenerative Disease and Memory Impairment, Capital Medical University, Beijing, 100053, PR China; Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing, 100053, PR China; Key Laboratory of Neurodegenerative Diseases, Ministry of Education, Beijing, 100053, PR China; National Clinical Research Center for Geriatric Disorders, Beijing, 100053, PR China.
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15
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Banerjee R, Rudloff Z, Naylor C, Yu MC, Gunawardena S. The presenilin loop region is essential for glycogen synthase kinase 3 β (GSK3β) mediated functions on motor proteins during axonal transport. Hum Mol Genet 2019; 27:2986-3001. [PMID: 29790963 DOI: 10.1093/hmg/ddy190] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 05/10/2018] [Indexed: 01/05/2023] Open
Abstract
Neurons require intracellular transport of essential components for function and viability and defects in transport has been implicated in many neurodegenerative diseases including Alzheimer's disease (AD). One possible mechanism by which transport defects could occur is by improper regulation of molecular motors. Previous work showed that reduction of presenilin (PS) or glycogen synthase kinase 3 beta (GSK3β) stimulated amyloid precursor protein vesicle motility. Excess GSK3β caused transport defects and increased motor binding to membranes, while reduction of PS decreased active GSK3β and motor binding to membranes. Here, we report that functional PS and the catalytic loop region of PS is essential for the rescue of GSK3β-mediated axonal transport defects. Disruption of PS loop (PSΔE9) or expression of the non-functional PS variant, PSD447A, failed to rescue axonal blockages in vivo. Further, active GSK3β associated with and phosphorylated kinesin-1 in vitro. Our observations together with previous work that showed that the loop region of PS interacts with GSK3β propose a scaffolding mechanism for PS in which the loop region sequesters GSK3β away from motors for the proper regulation of motor function. These findings are important to uncouple the complex regulatory mechanisms that likely exist for motor activity during axonal transport in vivo.
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Affiliation(s)
- Rupkatha Banerjee
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - Zoe Rudloff
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - Crystal Naylor
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - Michael C Yu
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - Shermali Gunawardena
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY 14260, USA
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16
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Oikawa N, Walter J. Presenilins and γ-Secretase in Membrane Proteostasis. Cells 2019; 8:cells8030209. [PMID: 30823664 PMCID: PMC6468700 DOI: 10.3390/cells8030209] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 02/26/2019] [Accepted: 02/27/2019] [Indexed: 12/20/2022] Open
Abstract
The presenilin (PS) proteins exert a crucial role in the pathogenesis of Alzheimer disease (AD) by mediating the intramembranous cleavage of amyloid precursor protein (APP) and the generation of amyloid β-protein (Aβ). The two homologous proteins PS1 and PS2 represent the catalytic subunits of distinct γ-secretase complexes that mediate a variety of cellular processes, including membrane protein metabolism, signal transduction, and cell differentiation. While the intramembrane cleavage of select proteins by γ-secretase is critical in the regulation of intracellular signaling pathways, the plethora of identified protein substrates could also indicate an important role of these enzyme complexes in membrane protein homeostasis. In line with this notion, PS proteins and/or γ-secretase has also been implicated in autophagy, a fundamental process for the maintenance of cellular functions and homeostasis. Dysfunction in the clearance of proteins in the lysosome and during autophagy has been shown to contribute to neurodegeneration. This review summarizes the recent knowledge about the role of PS proteins and γ-secretase in membrane protein metabolism and trafficking, and the functional relation to lysosomal activity and autophagy.
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Affiliation(s)
- Naoto Oikawa
- Department of Neurology, University of Bonn, 53127 Bonn, Germany.
| | - Jochen Walter
- Department of Neurology, University of Bonn, 53127 Bonn, Germany.
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17
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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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18
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Khan I, Krishnaswamy S, Sabale M, Groth D, Wijaya L, Morici M, Berger I, Schaffitzel C, Fraser PE, Martins RN, Verdile G. Efficient production of a mature and functional gamma secretase protease. Sci Rep 2018; 8:12834. [PMID: 30150752 PMCID: PMC6110731 DOI: 10.1038/s41598-018-30788-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 08/06/2018] [Indexed: 12/27/2022] Open
Abstract
Baculoviral protein expression in insect cells has been previously used to generate large quantities of a protein of interest for subsequent use in biochemical and structural analyses. The MultiBac baculovirus protein expression system has enabled, the use of a single baculovirus to reconstitute a protein complex of interest, resulting in a larger protein yield. Using this system, we aimed to reconstruct the gamma (γ)-secretase complex, a multiprotein enzyme complex essential for the production of amyloid-β (Aβ) protein. A MultiBac vector containing all components of the γ-secretase complex was generated and expression was observed for all components. The complex was active in processing APP and Notch derived γ-secretase substrates and proteolysis could be inhibited with γ-secretase inhibitors, confirming specificity of the recombinant γ-secretase enzyme. Finally, affinity purification was used to purify an active recombinant γ-secretase complex. In this study we demonstrated that the MultiBac protein expression system can be used to generate an active γ-secretase complex and provides a new tool to study γ-secretase enzyme and its variants.
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Affiliation(s)
- Imran Khan
- School of Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia. .,School of Psychiatry and Clinical Neurosciences, University of Western Australia, Crawley, Western Australia, Australia. .,Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
| | - Sudarsan Krishnaswamy
- Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
| | - Miheer Sabale
- School of Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
| | - David Groth
- School of Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
| | - Linda Wijaya
- Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.,School of Psychology and Exercise Sciences, Murdoch University, Murdoch, Western Australia, Australia
| | - Michael Morici
- School of Psychiatry and Clinical Neurosciences, University of Western Australia, Crawley, Western Australia, Australia.,Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
| | - Imre Berger
- European Molecular Biology Laboratories, Grenoble, France.,School of Biochemistry, University of Bristol, Bristol, UK
| | - Christiane Schaffitzel
- European Molecular Biology Laboratories, Grenoble, France.,School of Biochemistry, University of Bristol, Bristol, UK
| | - Paul E Fraser
- Tanz Centre for Research in Neurodegenerative Diseases and Department of Medical Biophysics, Krembil Discovery Tower, University of Toronto, Toronto, Ontario, Canada
| | - Ralph N Martins
- School of Psychiatry and Clinical Neurosciences, University of Western Australia, Crawley, Western Australia, Australia.,Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.,Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Giuseppe Verdile
- School of Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia. .,School of Psychiatry and Clinical Neurosciences, University of Western Australia, Crawley, Western Australia, Australia. .,Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
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19
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Verheijen BM, Stevens JAA, Gentier RJG, van 't Hekke CD, van den Hove DLA, Hermes DJHP, Steinbusch HWM, Ruijter JM, Grimm MOW, Haupenthal VJ, Annaert W, Hartmann T, van Leeuwen FW. Paradoxical effects of mutant ubiquitin on Aβ plaque formation in an Alzheimer mouse model. Neurobiol Aging 2018; 72:62-71. [PMID: 30216939 DOI: 10.1016/j.neurobiolaging.2018.08.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 07/03/2018] [Accepted: 08/10/2018] [Indexed: 01/08/2023]
Abstract
Amyloid-β (Aβ) plaques are a prominent pathological hallmark of Alzheimer's disease (AD). They consist of aggregated Aβ peptides, which are generated through sequential proteolytic processing of the transmembrane protein amyloid precursor protein (APP) and several Aβ-associated factors. Efficient clearance of Aβ from the brain is thought to be important to prevent the development and progression of AD. The ubiquitin-proteasome system (UPS) is one of the major pathways for protein breakdown in cells and it has been suggested that impaired UPS-mediated removal of protein aggregates could play an important role in the pathogenesis of AD. To study the effects of an impaired UPS on Aβ pathology in vivo, transgenic APPSwe/PS1ΔE9 mice (APPPS1) were crossed with transgenic mice expressing mutant ubiquitin (UBB+1), a protein-based inhibitor of the UPS. Surprisingly, the APPPS1/UBB+1 crossbreed showed a remarkable decrease in Aβ plaque load during aging. Further analysis showed that UBB+1 expression transiently restored PS1-NTF expression and γ-secretase activity in APPPS1 mice. Concurrently, UBB+1 decreased levels of β-APP-CTF, which is a γ-secretase substrate. Although UBB+1 reduced Aβ pathology in APPPS1 mice, it did not improve the behavioral deficits in these animals.
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Affiliation(s)
- Bert M Verheijen
- Department of Psychiatry and Neuropsychology, Faculty of Health Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Jo A A Stevens
- Department of Psychiatry and Neuropsychology, Faculty of Health Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Romina J G Gentier
- Department of Psychiatry and Neuropsychology, Faculty of Health Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Christian D van 't Hekke
- Department of Psychiatry and Neuropsychology, Faculty of Health Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Daniel L A van den Hove
- Department of Psychiatry and Neuropsychology, Faculty of Health Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands; Department of Psychiatry, Psychosomatics and Psychotherapy, University of Würzburg, Würzburg, Germany
| | - Denise J H P Hermes
- Department of Psychiatry and Neuropsychology, Faculty of Health Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Harry W M Steinbusch
- Department of Psychiatry and Neuropsychology, Faculty of Health Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Jan M Ruijter
- Department of Medical Biology, Academic Medical Center, Amsterdam, The Netherlands
| | - Marcus O W Grimm
- Deutsches Institut für Demenzprävention, University of Saarland, Experimental Neurology, Homburg, Germany
| | - Viola J Haupenthal
- Deutsches Institut für Demenzprävention, University of Saarland, Experimental Neurology, Homburg, Germany
| | - Wim Annaert
- VIB Center for Brain and Disease Research and KU Leuven, Gasthuisberg, Belgium
| | - Tobias Hartmann
- Deutsches Institut für Demenzprävention, University of Saarland, Experimental Neurology, Homburg, Germany
| | - Fred W van Leeuwen
- Department of Psychiatry and Neuropsychology, Faculty of Health Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands.
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20
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Medoro A, Bartollino S, Mignogna D, Passarella D, Porcile C, Pagano A, Florio T, Nizzari M, Guerra G, Di Marco R, Intrieri M, Raimo G, Russo C. Complexity and Selectivity of γ-Secretase Cleavage on Multiple Substrates: Consequences in Alzheimer's Disease and Cancer. J Alzheimers Dis 2018; 61:1-15. [PMID: 29103038 DOI: 10.3233/jad-170628] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The processing of the amyloid-β protein precursor (AβPP) by β- and γ-secretases is a pivotal event in the genesis of Alzheimer's disease (AD). Besides familial mutations on the AβPP gene, or upon its overexpression, familial forms of AD are often caused by mutations or deletions in presenilin 1 (PSEN1) and 2 (PSEN2) genes: the catalytic components of the proteolytic enzyme γ-secretase (GS). The "amyloid hypothesis", modified over time, states that the aberrant processing of AβPP by GS induces the formation of specific neurotoxic soluble amyloid-β (Aβ) peptides which, in turn, cause neurodegeneration. This theory, however, has recently evidenced significant limitations and, in particular, the following issues are debated: 1) the concept and significance of presenilin's "gain of function" versus "loss of function"; and 2) the presence of several and various GS substrates, which interact with AβPP and may influence Aβ formation. The latter consideration is suggestive: despite the increasing number of GS substrates so far identified, their reciprocal interaction with AβPP itself, even in the AD field, is significantly unexplored. On the other hand, GS is also an important pharmacological target in the cancer field; inhibitors or GS activity are investigated in clinical trials for treating different tumors. Furthermore, the function of AβPP and PSENs in brain development and in neuronal migration is well known. In this review, we focused on a specific subset of GS substrates that directly interact with AβPP and are involved in its proteolysis and signaling, by evaluating their role in neurodegeneration and in cell motility or proliferation, as a possible connection between AD and cancer.
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Affiliation(s)
- Alessandro Medoro
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, Campobasso, Italy
| | - Silvia Bartollino
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, Campobasso, Italy
| | - Donatella Mignogna
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, Campobasso, Italy
| | - Daniela Passarella
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, Campobasso, Italy
| | - Carola Porcile
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, Campobasso, Italy
| | - Aldo Pagano
- Department of Experimental Medicine, University of Genoa and Ospedale Policlinico San Martino, IRCCS per l'Oncologia, Genoa, Italy
| | - Tullio Florio
- Department of Internal Medicine and Centre of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
| | - Mario Nizzari
- Department of Internal Medicine and Centre of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
| | - Germano Guerra
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, Campobasso, Italy
| | - Roberto Di Marco
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, Campobasso, Italy
| | - Mariano Intrieri
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, Campobasso, Italy
| | - Gennaro Raimo
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, Campobasso, Italy
| | - Claudio Russo
- Department of Medicine and Health Sciences "V. Tiberio", University of Molise, Campobasso, Italy
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21
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Dong J, Qin W, Wei C, Tang Y, Wang Q, Jia J. A Novel PSEN1 K311R Mutation Discovered in Chinese Families with Late-Onset Alzheimer's Disease Affects Amyloid-β Production and Tau Phosphorylation. J Alzheimers Dis 2018; 57:613-623. [PMID: 28269784 DOI: 10.3233/jad-161188] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Presenilin-1 (PSEN1) is the most frequently mutated gene in familial Alzheimer's disease (AD), whereas only several novel mutations have been reported in China and functional studies were seldom conducted. OBJECTIVE We describe a novel PSEN1 K311R mutation in two Chinese families with late-onset AD and its functional impact on amyloid-β protein precursor (AβPP) processing and tau phosphorylation. METHODS The mutation was detected by direct sequencing of PSEN1 exon 9. HEK293 cells stably expressing wild-type APP695 (HEK293-APP695wt) were transfected with plasmids containing human wild-type PSEN1, PSEN1 K311R mutation, and PSEN1 E280A mutation to compare the K311R mutation's effects on AβPP processing with other groups. In addition, each group of cells were co-transfected with plasmids harboring PSEN1 and human wild-type MAPT complementary DNA to study the mutation's impacts on tau phosphorylation. RESULTS The K311R mutation was detected in probands of two late-onset AD families. Expression of the K311R or E280A mutation increased amyloid-β (Aβ)42 levels but decreased Aβ40 levels, resulting in an overall increase in the Aβ42/Aβ40 ratio compared to those in wild-type PSEN1 transfected cells (p < 0.05). The K311R or E280A mutation also increased the levels of phosphorylated tau compared to wild-type PSEN1 (p < 0.05). CONCLUSION The K311R mutation might contribute to AD pathogenesis by overproducing toxic Aβ species and enhancing tau phosphorylation. Further in-depth studies are needed to decipher the pathogenic mechanisms of the K311R mutation in terms of AβPP cleavage, tau phosphorylation, and other presenilin-1 mediated functional pathways.
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Affiliation(s)
- Jing Dong
- Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China
| | - Wei Qin
- Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China.,Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing, P.R. China.,Beijing Key Laboratory of Geriatric Cognitive Disorders, Beijing, P.R. China.,Key Neurodegenerative Laboratory of the Ministry of Education of the People's Republic of China, Beijing, P.R. China
| | - Cuibai Wei
- Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China.,Beijing Key Laboratory of Geriatric Cognitive Disorders, Beijing, P.R. China.,Key Neurodegenerative Laboratory of the Ministry of Education of the People's Republic of China, Beijing, P.R. China
| | - Yi Tang
- Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China
| | - Qi Wang
- Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China.,Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing, P.R. China.,Beijing Key Laboratory of Geriatric Cognitive Disorders, Beijing, P.R. China.,Key Neurodegenerative Laboratory of the Ministry of Education of the People's Republic of China, Beijing, P.R. China
| | - Jianping Jia
- Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China.,Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing, P.R. China.,Beijing Key Laboratory of Geriatric Cognitive Disorders, Beijing, P.R. China.,Key Neurodegenerative Laboratory of the Ministry of Education of the People's Republic of China, Beijing, P.R. China
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22
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Hu C, Xu J, Zeng L, Li T, Cui MZ, Xu X. Pen-2 and Presenilin are Sufficient to Catalyze Notch Processing. J Alzheimers Dis 2018; 56:1263-1269. [PMID: 28234257 DOI: 10.3233/jad-161094] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Presenilin-1 (PS1) or presenilin-2 (PS2), nicastrin (NCT), anterior pharynx-defective 1 (Aph-1), and presenilin enhancer-2 (Pen-2) have been considered the minimal essential subunits required to form an active γ-secretase complex. Besides PS, which has been widely believed to function as the catalytic subunit of the complex, the functional roles of the other subunits in the γ-secretase complex remain debatable. In the current study, we set out to determine the role of Pen-2 in γ-secretase activity. To this end, using knockout cells in combination with siRNA and immunoprecipitation approaches, our results revealed that Pen-2 together with presenilin are sufficient to form a functionally active enzyme to process Notch. Specifically, our data demonstrated that Pen-2 plays a crucial role in substrate binding, a mechanism by which Pen-2 contributes directly to the catalytic mechanism of γ-secretase activity. Our data also suggested that there may be different requirements for components to process AβPP and Notch. This information would be important for therapeutic strategy aimed at inhibition or modulation of γ-secretase activity.
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Affiliation(s)
- Chen Hu
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA
| | - Junjie Xu
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA.,Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Jilin Medical University, Jilin, China
| | - Linlin Zeng
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA.,School of Life Sciences, Jilin University, Changchun, China
| | - Ting Li
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA.,Department of Cell Biology, Tianjin Medical University, Tianjin, China
| | - Mei-Zhen Cui
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA
| | - Xuemin Xu
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA
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23
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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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24
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Somavarapu AK, Kepp KP. Membrane Dynamics of γ-Secretase Provides a Molecular Basis for β-Amyloid Binding and Processing. ACS Chem Neurosci 2017; 8:2424-2436. [PMID: 28841371 DOI: 10.1021/acschemneuro.7b00208] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
γ-Secretase produces β-amyloid (Aβ) within its presenilin (PS1) subunit, mutations in which cause Alzheimer's disease, and current therapies thus seek to modulate its activity. While the general structure is known from recent electron microscopy studies, direct loop and membrane interactions and explicit dynamics relevant to substrate processing remain unknown. We report a modeled structure utilizing the optimal multitemplate information available, including loops and missing side chains, account of maturation cleavage, and explicit all-atom molecular dynamics in the membrane. We observe three distinct conformations of γ-secretase (open, semiopen, and closed) that remarkably differ by tilting of helices 2 and 3 of PS1, directly controlling active site availability. The large hydrophilic loop of PS1 where maturation occurs reveals a new helix segment that parallels the likely helix character of other substrates. The semiopen conformation consistently shows the best fit of Aβ peptides, that is, longer residence before release and by inference more trimming. In contrast, the closed, hydrophobic conformation is largely inactive and the open conformation is active but provides fewer optimal interactions and induces shorter residence time and by inference releases Aβ peptides of longer lengths. Our simulations thus provide a molecular basis for substrate processing and changes in the Aβ42/Aβ40 ratio. Accordingly, selective binding to protect the semiopen "innocent" conformation provides a molecular recipe for effective γ-secretase modulators; we provide the full atomic structures for these states that may play a key role in developing selective γ-secretase modulators for treatment of Alzheimer's disease.
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Affiliation(s)
| | - Kasper P. Kepp
- Technical University of Denmark, DTU Chemistry, DK-2800 Kongens Lyngby, Denmark
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25
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Sogorb-Esteve A, García-Ayllón MS, Llansola M, Felipo V, Blennow K, Sáez-Valero J. Inhibition of γ-Secretase Leads to an Increase in Presenilin-1. Mol Neurobiol 2017; 55:5047-5058. [PMID: 28815510 PMCID: PMC5948247 DOI: 10.1007/s12035-017-0705-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 08/01/2017] [Indexed: 12/27/2022]
Abstract
γ-Secretase inhibitors (GSIs) are potential therapeutic agents for Alzheimer’s disease (AD); however, trials have proven disappointing. We addressed the possibility that γ-secretase inhibition can provoke a rebound effect, elevating the levels of the catalytic γ-secretase subunit, presenilin-1 (PS1). Acute treatment of SH-SY5Y cells with the GSI LY-374973 (N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester, DAPT) augments PS1, in parallel with increases in other γ-secretase subunits nicastrin, presenilin enhancer 2, and anterior pharynx-defective 1, yet with no increase in messenger RNA expression. Over-expression of the C-terminal fragment (CTF) of APP, C99, also triggered an increase in PS1. Similar increases in PS1 were evident in primary neurons treated repeatedly (4 days) with DAPT or with the GSI BMS-708163 (avagacestat). Likewise, rats examined after 21 days administered with avagacestat (40 mg/kg/day) had more brain PS1. Sustained γ-secretase inhibition did not exert a long-term effect on PS1 activity, evident through the decrease in CTFs of APP and ApoER2. Prolonged avagacestat treatment of rats produced a subtle impairment in anxiety-like behavior. The rebound increase in PS1 in response to GSIs must be taken into consideration for future drug development.
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Affiliation(s)
- Aitana Sogorb-Esteve
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Av. Ramón y Cajal s/n, 03550, Sant Joan d'Alacant, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Sant Joan d'Alacant, Spain
| | - María-Salud García-Ayllón
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Av. Ramón y Cajal s/n, 03550, Sant Joan d'Alacant, Spain. .,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Sant Joan d'Alacant, Spain. .,Unidad de Investigación, Hospital General Universitario de Elche, FISABIO, 03203, Elche, Spain.
| | - Marta Llansola
- Laboratory of Neurobiology, Fundación Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Vicente Felipo
- Laboratory of Neurobiology, Fundación Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Kaj Blennow
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden.,Institute of Neuroscience and Physiology, University of Gothenburg, Mölndal Campus, Sweden
| | - Javier Sáez-Valero
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Av. Ramón y Cajal s/n, 03550, Sant Joan d'Alacant, Spain. .,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Sant Joan d'Alacant, Spain.
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26
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Gertsik N, Am Ende CW, Geoghegan KF, Nguyen C, Mukherjee P, Mente S, Seneviratne U, Johnson DS, Li YM. Mapping the Binding Site of BMS-708163 on γ-Secretase with Cleavable Photoprobes. Cell Chem Biol 2017; 24:3-8. [PMID: 28065657 DOI: 10.1016/j.chembiol.2016.12.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 11/11/2016] [Accepted: 12/13/2016] [Indexed: 01/21/2023]
Abstract
γ-Secretase, a four-subunit transmembrane aspartic proteinase, is a highly valued drug target in Alzheimer's disease and cancer. Despite significant progress in structural studies, the respective molecular mechanisms and binding modes of γ-secretase inhibitors (GSIs) and modulators (GSMs) remain uncertain. Here, we developed biotinylated cleavable-linker photoprobes based on the BMS-708163 GSI to study its interaction with γ-secretase. Comparison of four cleavable linkers indicated that the hydrazine-labile N-1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl (Dde) linker was cleaved most efficiently to release photolabeled and affinity-captured presenilin-1 (PS1), the catalytic subunit of γ-secretase. Peptide mapping showed that the BMS-708163-based probe photoinserted at L282 of PS1. This insertion site was consistent with the results of molecular dynamics simulations of the γ-secretase complex with inhibitor. Taken together, this work reveals the binding site of a GSI and offers insights into the mechanism of action of this class of inhibitors.
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Affiliation(s)
- Natalya Gertsik
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Biochemistry and Molecular Biology Program, Weill Graduate School of Medical Sciences of Cornell University, New York, NY 10021, USA
| | - Christopher W Am Ende
- Pfizer Worldwide Research and Development, Neuroscience Medicinal Chemistry, Groton, CT 06340, USA
| | - Kieran F Geoghegan
- Pfizer Worldwide Research and Development, Structural and Molecular Sciences, Groton, CT 06340, USA
| | - Chuong Nguyen
- Pfizer Worldwide Research and Development, Structural and Molecular Sciences, Groton, CT 06340, USA
| | - Paramita Mukherjee
- Pfizer Worldwide Research and Development, Neuroscience Medicinal Chemistry, Groton, CT 06340, USA
| | - Scot Mente
- Pfizer Worldwide Research and Development, Neuroscience Medicinal Chemistry and Chemical Biology, Cambridge, MA 02139, USA
| | - Uthpala Seneviratne
- Pfizer Worldwide Research and Development, Neuroscience Medicinal Chemistry and Chemical Biology, Cambridge, MA 02139, USA
| | - Douglas S Johnson
- Pfizer Worldwide Research and Development, Neuroscience Medicinal Chemistry and Chemical Biology, Cambridge, MA 02139, USA.
| | - Yue-Ming Li
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Xiangya International Academy of Translational Medicine, Central South University, Changsha, Hunan 410013, China.
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27
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Huang HC, Zheng BW, Guo Y, Zhao J, Zhao JY, Ma XW, Jiang ZF. Antioxidative and Neuroprotective Effects of Curcumin in an Alzheimer’s Disease Rat Model Co-Treated with Intracerebroventricular Streptozotocin and Subcutaneous D-Galactose. J Alzheimers Dis 2016; 52:899-911. [DOI: 10.3233/jad-150872] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Han-Chang Huang
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China
- College of Arts and Science, Beijing Union University, Beijing, China
| | - Bo-Wen Zheng
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China
| | - Yu Guo
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China
- College of Arts and Science, Beijing Union University, Beijing, China
| | - Jian Zhao
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China
- College of Arts and Science, Beijing Union University, Beijing, China
| | - Jiang-Yan Zhao
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China
- College of Arts and Science, Beijing Union University, Beijing, China
| | - Xiao-Wei Ma
- College of Arts and Science, Beijing Union University, Beijing, China
| | - Zhao-Feng Jiang
- Beijing Key Laboratory of Bioactive Substances and Functional Foods, Beijing Union University, Beijing, China
- College of Arts and Science, Beijing Union University, Beijing, China
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28
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Pham K, Miksovska J. Molecular insight of DREAM and presenilin 1 C-terminal fragment interactions. FEBS Lett 2016; 590:1114-22. [PMID: 27009418 DOI: 10.1002/1873-3468.12156] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 02/24/2016] [Accepted: 03/21/2016] [Indexed: 12/21/2022]
Abstract
Interactions between downstream regulatory element antagonist modulator (DREAM) and presenilin 1 (PS1) are related to numerous neuronal processes. We demonstrate that association of PS1 carboxyl peptide (residues 445-467, HL9) with DREAM is calcium dependent and stabilized by a cluster of three aromatic residues: F462 and F465 from PS1 and F252 from DREAM. Additional stabilization is provided by residues in a loop connecting α helices 7 and 8 in DREAM and residues of PS1, namely cation-π interactions between R200 in DREAM and F465 in PS1 and the salt bridges formed by R207 in DREAM and D450 and D458 in PS1.
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Affiliation(s)
- Khoa Pham
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA
| | - Jaroslava Miksovska
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA.,Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
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29
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Somavarapu AK, Kepp KP. The dynamic mechanism of presenilin-1 function: Sensitive gate dynamics and loop unplugging control protein access. Neurobiol Dis 2016; 89:147-56. [PMID: 26852951 DOI: 10.1016/j.nbd.2016.02.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 02/02/2016] [Accepted: 02/03/2016] [Indexed: 12/20/2022] Open
Abstract
There is no molecular explanation for the many presenilin 1 (PSEN1) mutations causing Alzheimer's disease, but both gain of function relating to amyloid production and loss of isolated PSEN1 function have been implied. We report here the first detailed dynamic all-atom model of mature PSEN1 from molecular dynamics in an explicit membrane with particular account of the as yet unexplored loop dynamics. We find that mature PSEN1 contains multiple distinct conformational states whereas non-mature PSEN1 is a typical one-state protein. We confirm a previously suggested gating mechanism, and find that the 106-131 loop acts as a "hinge" for the TM2 and TM6 "doors". More importantly, we identify an unplugging mechanism of the Exon 9 loop associated only with mature PSEN1. Proper opening of both the "gate" and "plug" in the membrane produces channel-like morphologies and access to the catalytic aspartates. Dynamically, these features seem linked. The long-range sensitivity of this gate-plug system to subtle conformational changes can explain why so many PSEN1 mutants cause disease. Reduced access and imprecise substrate cleavage associated with impaired gate-plug dynamics is directly illustrated by the effect of maturation in our work and could explain the overall reduction in Aβ levels upon PSEN1 mutation and the increase in the Aβ 42/40 ratio. Yet, our PSEN1-only dynamics are particularly insightful in revealing PSEN1-only dynamics relating to e.g. its role as membrane channel. Thus, our identified gate-plug mechanism is relevant for designing PSEN1 modulating therapies for treatment of Alzheimer's disease within both the amyloid/γ-secretase hypothesis and within the PSEN1 loss of function paradigm.
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Affiliation(s)
| | - Kasper P Kepp
- Technical University of Denmark, DTU Chemistry, DK-2800 Kongens Lyngby, Denmark.
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30
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Chen AC, Kim S, Shepardson N, Patel S, Hong S, Selkoe DJ. Physical and functional interaction between the α- and γ-secretases: A new model of regulated intramembrane proteolysis. J Cell Biol 2015; 211:1157-76. [PMID: 26694839 PMCID: PMC4687875 DOI: 10.1083/jcb.201502001] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 11/11/2015] [Indexed: 12/20/2022] Open
Abstract
Many single-transmembrane proteins are sequentially cleaved by ectodomain-shedding α-secretases and the γ-secretase complex, a process called regulated intramembrane proteolysis (RIP). These cleavages are thought to be spatially and temporally separate. In contrast, we provide evidence for a hitherto unrecognized multiprotease complex containing both α- and γ-secretase. ADAM10 (A10), the principal neuronal α-secretase, interacted and cofractionated with γ-secretase endogenously in cells and mouse brain. A10 immunoprecipitation yielded γ-secretase proteolytic activity and vice versa. In agreement, superresolution microscopy showed that portions of A10 and γ-secretase colocalize. Moreover, multiple γ-secretase inhibitors significantly increased α-secretase processing (r = -0.86) and decreased β-secretase processing of β-amyloid precursor protein. Select members of the tetraspanin web were important both in the association between A10 and γ-secretase and the γ → α feedback mechanism. Portions of endogenous BACE1 coimmunoprecipitated with γ-secretase but not A10, suggesting that β- and α-secretases can form distinct complexes with γ-secretase. Thus, cells possess large multiprotease complexes capable of sequentially and efficiently processing transmembrane substrates through a spatially coordinated RIP mechanism.
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Affiliation(s)
- Allen C Chen
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Sumin Kim
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Nina Shepardson
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Sarvagna Patel
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Soyon Hong
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115
| | - Dennis J Selkoe
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
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31
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Walter J. Twenty Years of Presenilins--Important Proteins in Health and Disease. Mol Med 2015; 21 Suppl 1:S41-8. [PMID: 26605647 DOI: 10.2119/molmed.2015.00163] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 07/01/2015] [Indexed: 01/01/2023] Open
Abstract
Alzheimer's disease (AD) is characterized by progressive decline in cognitive functions associated with depositions of aggregated proteins in the form of extracellular plaques and neurofibrillary tangles in the brain. Extracellular plaques contain characteristic fibrils of amyloid β peptides (Aβ); tangles consist of paired helical filaments of the microtubuli-associated protein tau. Although AD manifests predominantly at ages above 65 years, rare cases show a much earlier onset of disease symptoms with very similar neuropathological characteristics. In 1995, two homologous genes were identified, in which mutations are associated with dominantly inherited familial forms of early onset AD. The genes therefore were dubbed presenilins (PS) and encode polytopic transmembrane proteins. At this time the role of these proteins in the pathogenesis of AD and their biological function in general were completely unknown. However, individuals carrying PS mutations showed alterations in the composition of different length variants of Aβ peptides in blood and cerebrospinal fluid, which indicated the potential involvement of presenilins in the metabolism of Aβ. After 20 years of intense research, the roles of presenilins in Aβ generation as well as important functions in biological processes have been identified. Presenilins represent the catalytic components of protease complexes that directly cleave the amyloid precursor protein (APP) but also many other proteins with important physiological functions. Here, the progress in presenilin research from basic characterization of their cellular functions to the targeting in clinical trials for AD therapy, and potential future directions, will be discussed.
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Affiliation(s)
- Jochen Walter
- Department of Neurology, University of Bonn, Bonn, Germany
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32
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Gertsik N, Chiu D, Li YM. Complex regulation of γ-secretase: from obligatory to modulatory subunits. Front Aging Neurosci 2015; 6:342. [PMID: 25610395 PMCID: PMC4285130 DOI: 10.3389/fnagi.2014.00342] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 12/09/2014] [Indexed: 11/29/2022] Open
Abstract
γ-Secretase is a four subunit, 19-pass transmembrane enzyme that cleaves amyloid precursor protein (APP), catalyzing the formation of amyloid beta (Aβ) peptides that form amyloid plaques, which contribute to Alzheimer’s disease (AD) pathogenesis. γ-Secretase also cleaves Notch, among many other type I transmembrane substrates. Despite its seemingly promiscuous enzymatic capacity, γ-secretase activity is tightly regulated. This regulation is a function of many cellular entities, including but not limited to the essential γ-secretase subunits, nonessential (modulatory) subunits, and γ-secretase substrates. Regulation is also accomplished by an array of cellular events, such as presenilin (active subunit of γ-secretase) endoproteolysis and hypoxia. In this review we discuss how γ-secretase is regulated with the hope that an advanced understanding of these mechanisms will aid in the development of effective therapeutics for γ-secretase-associated diseases like AD and Notch-addicted cancer.
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Affiliation(s)
- Natalya Gertsik
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center New York, NY, USA ; Biochemistry and Molecular Biology Program, Weill Graduate School of Medical Sciences of Cornell University New York, NY, USA
| | - Danica Chiu
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center New York, NY, USA ; Program of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University New York, NY, USA
| | - Yue-Ming Li
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center New York, NY, USA ; Program of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University New York, NY, USA
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33
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Li Y, Bohm C, Dodd R, Chen F, Qamar S, Schmitt-Ulms G, Fraser PE, St George-Hyslop PH. Structural biology of presenilin 1 complexes. Mol Neurodegener 2014; 9:59. [PMID: 25523933 PMCID: PMC4326451 DOI: 10.1186/1750-1326-9-59] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 12/12/2014] [Indexed: 11/17/2022] Open
Abstract
The presenilin genes were first identified as the site of missense mutations causing early onset autosomal dominant familial Alzheimer's disease. Subsequent work has shown that the presenilin proteins are the catalytic subunits of a hetero-tetrameric complex containing APH1, nicastrin and PEN-2. This complex (variously termed presenilin complex or gamma-secretase complex) performs an unusual type of proteolysis in which the transmembrane domains of Type I proteins are cleaved within the hydrophobic compartment of the membrane. This review describes some of the molecular and structural biology of this unusual enzyme complex. The presenilin complex is a bilobed structure. The head domain contains the ectodomain of nicastrin. The base domain contains a central cavity with a lateral cleft that likely provides the route for access of the substrate to the catalytic cavity within the centre of the base domain. There are reciprocal allosteric interactions between various sites in the complex that affect its function. For instance, binding of Compound E, a peptidomimetic inhibitor to the PS1 N-terminus, induces significant conformational changes that reduces substrate binding at the initial substrate docking site, and thus inhibits substrate cleavage. However, there is a reciprocal allosteric interaction between these sites such that prior binding of the substrate to the initial docking site paradoxically increases the binding of the Compound E peptidomimetic inhibitor. Such reciprocal interactions are likely to form the basis of a gating mechanism that underlies access of substrate to the catalytic site. An increasingly detailed understanding of the structural biology of the presenilin complex is an essential step towards rational design of substrate- and/or cleavage site-specific modulators of presenilin complex function.
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Affiliation(s)
| | | | | | | | | | | | | | - Peter H St George-Hyslop
- Cambridge Institute for Medical Research, Wellcome Trust MRC Building, Addenbrookes Hospital, Hills Road, Cambridge CB2 0XY, UK.
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34
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Zhang X, Li Y, Xu H, Zhang YW. The γ-secretase complex: from structure to function. Front Cell Neurosci 2014; 8:427. [PMID: 25565961 PMCID: PMC4263104 DOI: 10.3389/fncel.2014.00427] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 11/27/2014] [Indexed: 12/21/2022] Open
Abstract
One of the most critical pathological features of Alzheimer’s disease (AD) is the accumulation of β-amyloid (Aβ) peptides that form extracellular senile plaques in the brain. Aβ is derived from β-amyloid precursor protein (APP) through sequential cleavage by β- and γ-secretases. γ-secretase is a high molecular weight complex minimally composed of four components: presenilins (PS), nicastrin, anterior pharynx defective 1 (APH-1), and presenilin enhancer 2 (PEN-2). In addition to APP, γ-secretase also cleaves many other type I transmembrane (TM) protein substrates. As a crucial enzyme for Aβ production, γ-secretase is an appealing therapeutic target for AD. Here, we summarize current knowledge on the structure and function of γ-secretase, as well as recent progress in developing γ-secretase targeting drugs for AD treatment.
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Affiliation(s)
- Xian Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University Xiamen, FJ, China
| | - Yanfang Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University Xiamen, FJ, China
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University Xiamen, FJ, China ; Degenerative Disease Research Program, Sanford-Burnham Medical Research Institute La Jolla, CA, USA
| | - Yun-Wu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University Xiamen, FJ, China
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35
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Haapasalo A, Viswanathan J, Kurkinen KM, Bertram L, Soininen H, Dantuma NP, Tanzi RE, Hiltunen M. Involvement of ubiquilin-1 transcript variants in protein degradation and accumulation. Commun Integr Biol 2014. [DOI: 10.4161/cib.15283] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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36
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A novel presenilin 1 mutation (Ala275Val) as cause of early-onset familial Alzheimer disease. Neurosci Lett 2014; 566:115-9. [DOI: 10.1016/j.neulet.2014.02.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 01/22/2014] [Accepted: 02/17/2014] [Indexed: 11/23/2022]
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37
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Wolfe MS. Toward the structure of presenilin/γ-secretase and presenilin homologs. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1828:2886-97. [PMID: 24099007 PMCID: PMC3801419 DOI: 10.1016/j.bbamem.2013.04.015] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 04/03/2013] [Accepted: 04/11/2013] [Indexed: 01/30/2023]
Abstract
Presenilin is the catalytic component of the γ-secretase complex, a membrane-embedded aspartyl protease that plays a central role in biology and in the pathogenesis of Alzheimer's disease. Upon assembly with its three protein cofactors (nicastrin, Aph-1 and Pen-2), presenilin undergoes autoproteolysis into two subunits, each of which contributes one of the catalytic aspartates to the active site. A family of presenilin homologs, including signal peptide peptidase, possess proteolytic activity without the need for other protein factors, and these simpler intramembrane aspartyl proteases have given insight into the action of presenilin within the γ-secretase complex. Cellular and molecular studies support a nine-transmembrane topology for presenilins and their homologs, and small-molecule inhibitors and cysteine scanning with crosslinking have suggested certain presenilin residues and regions that contribute to substrate recognition and handling. Identification of partial complexes has also offered clues to protein-protein interactions within the γ-secretase complex. Biophysical methods have allowed 3D views of the γ-secretase complex and presenilins. Most recently, the crystal structure of a microbial presenilin homolog has confirmed a nine-transmembrane topology and intramembranous location and proximity of the two conserved and essential aspartates. The crystal structure also provides a platform for the formulation of specific hypotheses regarding substrate interaction and catalysis as well as the pathogenic mechanism of Alzheimer-causing presenilin mutations. This article is part of a Special Issue entitled: Intramembrane Proteases.
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Affiliation(s)
- Michael S Wolfe
- Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, H.I.M. 754, Boston, MA 02115 USA.
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Newman M, Wilson L, Verdile G, Lim A, Khan I, Moussavi Nik SH, Pursglove S, Chapman G, Martins RN, Lardelli M. Differential, dominant activation and inhibition of Notch signalling and APP cleavage by truncations of PSEN1 in human disease. Hum Mol Genet 2013; 23:602-17. [DOI: 10.1093/hmg/ddt448] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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García-Ayllón MS, Campanari ML, Brinkmalm G, Rábano A, Alom J, Saura CA, Andreasen N, Blennow K, Sáez-Valero J. CSF Presenilin-1 complexes are increased in Alzheimer's disease. Acta Neuropathol Commun 2013; 1:46. [PMID: 24252417 PMCID: PMC3893612 DOI: 10.1186/2051-5960-1-46] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Accepted: 08/04/2013] [Indexed: 11/24/2022] Open
Abstract
Background Presenilin-1 (PS1) is the active component of the amyloid precursor protein cleaving γ-secretase complex. PS1 protein is a transmembrane protein containing multiple hydrophobic regions which presence in cerebrospinal fluid (CSF) has not been measured to date. This study assesses whether PS1 and other components of the γ-secretase complex are present in CSF. Results Here, we show that PS1 is present in ventricular post-mortem and lumbar ante-mortem CSF, and plasma as 100–150-kDa hetero-complexes containing both the N- and C-terminal fragments (NTF and CTF) of the protein. Immunoprecipitation and immunoblotting with different antibodies confirmed the identity of the PS1 species. The γ-secretase components, APH-1 (anterior pharynx-defective 1) and PEN-2 (presenilin enhancer 2), as well as presenilin-2 (PS2) fragments, co-exist within these CSF complexes, while nicastrin is not detected. These CSF-PS1 complexes differ from active γ-secretase membrane-complexes, and may represent nonspecific aggregation of the PS1 protein. Levels of PS1 complexes are increased in CSF samples from autopsy-confirmed Alzheimer’s disease (AD) cases and were found to be more stable than complexes in CSF from control subjects. Despite similar levels of total PS1 in CSF from probable AD patients and cognitively normal subjects, an increased proportion of highly stable PS1 complexes were observed in AD CSF. Conclusions Our data suggest that fragments of the PS1 protein present in CSF as complexes may be useful as a biomarker for AD.
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40
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Zhang S, Zhang M, Cai F, Song W. Biological function of Presenilin and its role in AD pathogenesis. Transl Neurodegener 2013; 2:15. [PMID: 23866842 PMCID: PMC3718700 DOI: 10.1186/2047-9158-2-15] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Accepted: 07/14/2013] [Indexed: 01/06/2023] Open
Abstract
Presenilins (PSs) are the catalytic core of γ-secretase complex. However, the mechanism of FAD-associated PS mutations in AD pathogenesis still remains elusive. Here we review the general biology and mechanism of γ-secretase and focus on the catalytic components – presenilins and their biological functions and contributions to the AD pathogenesis. The functions of presenilins are divided into γ-secretase dependent and γ-secretase independent ones. The γ-secretase dependent functions of presenilins are exemplified by the sequential cleavages in the processing of APP and Notch; the γ-secretase independent functions of presenilins include stabilizing β-catenin in Wnt signaling pathway, regulating calcium homeostasis and their interaction with synaptic transmission.
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Affiliation(s)
- Shuting 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.
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41
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Strisovsky K. Structural and mechanistic principles of intramembrane proteolysis--lessons from rhomboids. FEBS J 2013; 280:1579-603. [PMID: 23432912 DOI: 10.1111/febs.12199] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 02/11/2013] [Accepted: 02/18/2013] [Indexed: 02/03/2023]
Abstract
Intramembrane proteases cleave membrane proteins in their transmembrane helices to regulate a wide range of biological processes. They catalyse hydrolytic reactions within the hydrophobic environment of lipid membranes where water is normally excluded. How? Do the different classes of intramembrane proteases share any mechanistic principles? In this review these questions will be discussed in view of the crystal structures of prokaryotic members of the three known catalytic types of intramembrane proteases published over the past 7 years. Rhomboids, the intramembrane serine proteases that are the best understood family, will be the initial area of focus, and the principles that have arisen from a number of structural and biochemical studies will be considered. The site-2 metalloprotease and GXGD-type aspartyl protease structures will then be discussed, with parallels drawn and differences highlighted between these enzymes and the rhomboids. Despite the significant advances achieved so far, to obtain a detailed understanding of the mechanism of any intramembrane protease, high-resolution structural information on the substrate-enzyme complex is required. This remains a major challenge for the field.
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Affiliation(s)
- Kvido Strisovsky
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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Mao G, Cui MZ, Li T, Jin Y, Xu X. Pen-2 is dispensable for endoproteolysis of presenilin 1, and nicastrin-Aph subcomplex is important for both γ-secretase assembly and substrate recruitment. J Neurochem 2012; 123:837-44. [PMID: 22973949 DOI: 10.1111/jnc.12016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 09/05/2012] [Accepted: 09/06/2012] [Indexed: 11/30/2022]
Abstract
γ-secretase is a protease complex with at least four components: presenilin, nicastrin (NCT), anterior pharynx-defective 1 (Aph-1), and presenilin enhancer 2 (Pen-2). In this study, using knockout cell lines and small interfering RNA technology, our data demonstrated that the disappeared presenilin 1 C-terminal fragment (PS1C) caused by knockdown of pen-2 or knockout of NCT or Aph-1 was recovered by the addition of proteasome inhibitors, indicating that Pen-2, as well as NCT and Aph-1α, is dispensable for presenilin endoproteolysis. Our data also demonstrate that the formation of the nicastrin-Aph-1 subcomplex plays not only an important role in γ-secretase complex assembly but also in recruiting substrate C-terminal fragment of amyloid precursor protein generated by β-cleavage. Ablating any one component resulted in the instability of other components of the γ-secretase complex, and the presence of all three of the other components is required for full maturation of NCT.
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Affiliation(s)
- Guozhang Mao
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN, USA
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43
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A role for presenilins in autophagy revisited: normal acidification of lysosomes in cells lacking PSEN1 and PSEN2. J Neurosci 2012; 32:8633-48. [PMID: 22723704 DOI: 10.1523/jneurosci.0556-12.2012] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Presenilins 1 and 2 (PS1 and PS2) are the catalytic subunits of the γ-secretase complex, and genes encoding mutant PS1 and PS2 variants cause familial forms of Alzheimer's disease. Lee et al. (2010) recently reported that loss of PS1 activity lead to impairments in autophagosomal function as a consequence of lysosomal alkalinization, caused by failed maturation of the proton translocating V0a1 subunit of the vacuolar (H+)-ATPase and targeting to the lysosome. We have reexamined these issues in mammalian cells and in brains of mice lacking PS (PScdko) and have been unable to find evidence that the turnover of autophagic substrates, vesicle pH, V0a1 maturation, or lysosome function is altered compared with wild-type counterparts. Collectively, our studies fail to document a role for presenilins in regulating cellular autophagosomal function. On the other hand, our transcriptome studies of PScdko mouse brains reveal, for the first time, a role for PS in regulating lysosomal biogenesis.
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44
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Mittendorf KF, Deatherage CL, Ohi MD, Sanders CR. Tailoring of membrane proteins by alternative splicing of pre-mRNA. Biochemistry 2012; 51:5541-56. [PMID: 22708632 DOI: 10.1021/bi3007065] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Alternative splicing (AS) of RNA is a key mechanism for diversification of the eukaryotic proteome. In this process, different mRNA transcripts can be produced through altered excision and/or inclusion of exons during processing of the pre-mRNA molecule. Since its discovery, AS has been shown to play roles in protein structure, function, and localization. Dysregulation of this process can result in disease phenotypes. Moreover, AS pathways are promising therapeutic targets for a number of diseases. Integral membrane proteins (MPs) represent a class of proteins that may be particularly amenable to regulation by alternative splicing because of the distinctive topological restraints associated with their folding, structure, trafficking, and function. Here, we review the impact of AS on MP form and function and the roles of AS in MP-related disorders such as Alzheimer's disease.
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Affiliation(s)
- Kathleen F Mittendorf
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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45
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Ye Y, Gao JX, Tian H, Yearsley K, Lange AR, Robertson FM, Barsky SH. Early to Intermediate Steps of Tumor Embolic Formation Involve Specific Proteolytic Processing of E-Cadherin Regulated by Rab7. Mol Cancer Res 2012; 10:713-26. [DOI: 10.1158/1541-7786.mcr-12-0009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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46
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van Tetering G, Vooijs M. Proteolytic cleavage of Notch: "HIT and RUN". Curr Mol Med 2011; 11:255-69. [PMID: 21506924 DOI: 10.2174/156652411795677972] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 02/07/2011] [Indexed: 01/03/2023]
Abstract
The Notch pathway is a highly conserved signaling pathway in multicellular eukaryotes essential in controlling spatial patterning, morphogenesis and homeostasis in embryonic and adult tissues. Notch proteins coordinate cell-cell communication through receptor-ligand interactions between adjacent cells. Notch signaling is frequently deregulated by oncogenic mutation or overexpression in many cancer types. Notch activity is controlled by three sequential cleavage steps leading to ectodomain shedding and transcriptional activation. Here we review the key regulatory steps in the activation of Notch, from receptor maturation to receptor activation (HIT) via a rate-limiting proteolytic cascade (RUN) in the context of species-specific differences.
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Affiliation(s)
- G van Tetering
- Department of Pathology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
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47
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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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48
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Haapasalo A, Viswanathan J, Kurkinen KM, Bertram L, Soininen H, Dantuma NP, Tanzi RE, Hiltunen M. Involvement of ubiquilin-1 transcript variants in protein degradation and accumulation. Commun Integr Biol 2011; 4:428-32. [PMID: 21966562 DOI: 10.4161/cib.4.4.15283] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 02/24/2011] [Indexed: 11/19/2022] Open
Abstract
Controlled management of protein levels and quality is essential for normal cellular function. Specific molecular chaperones and foldases monitor the levels and assist correct folding of proteins. The ubiquitin-proteasome system recognizes and degrades misfolded proteins that can otherwise be harmful to cells. However, when misfolded or aggregated proteins excessively accumulate, they may be sequestered to the microtubule-organizing center to form aggresomes. These may then be removed from cells by autophagocytosis. Abnormal protein accumulation and aggregation is a common hallmark of many neurodegenerative diseases. In a recent study, we provide evidence that specific transcript variants (TVs) of ubiquilin-1, which are genetically and functionally associated to Alzheimer's disease (AD), regulate proteasomal and aggresomal targeting of presenilin-1 (PS1), a key player in AD pathogenesis. Our study together with current data provide interesting implications for ubiquilin-1 and its TVs in the pathogenesis of AD and other neurodegenerative diseases involving abnormal protein aggregation.
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Affiliation(s)
- Annakaisa Haapasalo
- Institute of Clinical Medicine - Neurology; University of Eastern Finland; Kuopio, Finland
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49
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Teranishi Y, Hur JY, Welander H, Frånberg J, Aoki M, Winblad B, Frykman S, Tjernberg LO. Affinity pulldown of γ-secretase and associated proteins from human and rat brain. J Cell Mol Med 2011; 14:2675-86. [PMID: 19754663 PMCID: PMC4373488 DOI: 10.1111/j.1582-4934.2009.00907.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
γ-Secretase is a transmembrane protease complex responsible for the processing of a multitude of type 1 transmembrane proteins, including amyloid precursor protein (APP) and Notch. A functional complex is dependent on the assembly of four proteins: presenilin (PS), nicastrin, Aph-1 and Pen-2. Little is known about how the substrates are selected by γ-secretase, but it has been suggested that γ-secretase associated proteins (GSAPs) could be of importance. For instance, it was recently reported from studies in cell lines that TMP21, a transmembrane protein involved in trafficking, binds to γ-secretase and regulates the processing of APP-derived substrates without affecting Notch cleavage. Here, we present an efficient and selective method for purification and analysis of γ-secretase and GSAPs. Microsomal membranes were prepared from rat or human brain and incubated with a γ-secretase inhibitor coupled to biotin via a long linker and a S-S bridge. After pulldown using streptavidin beads, bound proteins were eluted under reducing conditions and digested by trypsin. The tryptic peptides were subjected to LC-MS/MS analysis, and proteins were identified by sequence data from MS/MS spectra. All of the known γ-secretase components were identified. Interestingly, TMP21 and the PS associated protein syntaxin1 were associated to γ-secretase in rat brain. We suggest that the present method can be used for further studies on the composition of the γ-secretase complex.
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Affiliation(s)
- Yasuhiro Teranishi
- The Karolinska Institutet (KI) Dainippon Sumitomo Pharma Alzheimer Center (KASPAC), KI-Alzheimer's Disease Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Novum, Huddinge, Sweden
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50
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Lichtenthaler SF, Haass C, Steiner H. Regulated intramembrane proteolysis--lessons from amyloid precursor protein processing. J Neurochem 2011; 117:779-96. [PMID: 21413990 DOI: 10.1111/j.1471-4159.2011.07248.x] [Citation(s) in RCA: 176] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Regulated intramembrane proteolysis (RIP) controls the communication between cells and the extracellular environment. RIP is essential in the nervous system, but also in other tissues. In the RIP process, a membrane protein typically undergoes two consecutive cleavages. The first one results in the shedding of its ectodomain. The second one occurs within its transmembrane domain, resulting in secretion of a small peptide and the release of the intracellular domain into the cytosol. The proteolytic cleavage fragments act as versatile signaling molecules or are further degraded. An increasing number of membrane proteins undergo RIP. These include growth factors, cytokines, cell adhesion proteins, receptors, viral proteins and signal peptides. A dysregulation of RIP is found in diseases, such as leukemia and Alzheimer's disease. One of the first RIP substrates discovered was the amyloid precursor protein (APP). RIP processing of APP controls the generation of the amyloid β-peptide, which is believed to cause Alzheimer's disease. Focusing on APP as the best-studied RIP substrate, this review describes the function and mechanism of the APP RIP proteases with the goal to elucidate cellular mechanisms and common principles of the RIP process in general.
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Affiliation(s)
- Stefan F Lichtenthaler
- DZNE-German Center for Neurodegenerative Diseases, Adolf-Butenandt-Institute, Biochemistry, Ludwig-Maximilians-University, Munich, Germany
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