scholarly journals Crystal Structure of an Active Form of BACE1, an Enzyme Responsible for Amyloid β Protein Production

2008 ◽  
Vol 28 (11) ◽  
pp. 3663-3671 ◽  
Author(s):  
Hideaki Shimizu ◽  
Asako Tosaki ◽  
Kumi Kaneko ◽  
Tamao Hisano ◽  
Takashi Sakurai ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Active Form ◽  
Amyloid Β ◽  
Bound Water ◽  
Structural Features ◽  
Cellular Trafficking ◽  
Amyloid Β Peptide ◽  
Amyloid Β Protein ◽  
Catalytically Active ◽  
Bace1 Activity

ABSTRACT BACE1 (β-secretase) is a transmembrane aspartic protease that cleaves the β-amyloid precursor protein and generates the amyloid β peptide (Aβ). BACE1 cycles between the cell surface and the endosomal system many times and becomes activated interconvertibly during its cellular trafficking, leading to the production of Aβ. Here we report the crystal structure of the catalytically active form of BACE1. The active form has novel structural features involving the conformation of the flap and subsites that promote substrate binding. The functionally essential residues and water molecules are well defined and play a key role in the iterative activation of BACE1. We further describe the crystal structure of the dehydrated form of BACE1, showing that BACE1 activity is dependent on the dynamics of a catalytically required Asp-bound water molecule, which directly affects its catalytic properties. These findings provide insight into a novel regulation of BACE1 activity and elucidate how BACE1 modulates its activity during cellular trafficking.

scholarly journals A Super-Resolved View of the Alzheimer’s Disease-Related Amyloidogenic Pathway in Hippocampal Neurons

2021 ◽  
pp. 1-20
Author(s):  
Yang Yu ◽  
Yang Gao ◽  
Bengt Winblad ◽  
Lars Tjernberg ◽  
Sophia Schedin Weiss
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Hippocampal Neurons ◽  
Three Dimensional ◽  
Amyloid Β ◽  
Stimulated Emission ◽  
Amyloid Β Peptide ◽  
Primary Neurons ◽  
Amyloid Β Protein ◽  
Early Endosomes

Background: Processing of the amyloid-β protein precursor (AβPP) is neurophysiologically important due to the resulting fragments that regulate synapse biology, as well as potentially harmful due to generation of the 42 amino acid long amyloid β-peptide (Aβ 42), which is a key player in Alzheimer’s disease. Objective: Our aim was to clarify the subcellular locations of the amyloidogenic AβPP processing in primary neurons, including the intracellular pools of the immediate substrate, AβPP C-terminal fragment (APP-CTF) and the product (Aβ 42). To overcome the difficulties of resolving these compartments due to their small size, we used super-resolution microscopy. Methods: Mouse primary hippocampal neurons were immunolabelled and imaged by stimulated emission depletion (STED) microscopy, including three-dimensional, three-channel imaging and image analyses. Results: The first (β-secretase) and second (γ-secretase) cleavages of AβPP were localized to functionally and distally distinct compartments. The β-secretase cleavage was observed in early endosomes, where we were able to show that the liberated N- and C-terminal fragments were sorted into distinct vesicles budding from the early endosomes in soma. Lack of colocalization of Aβ 42 and APP-CTF in soma suggested that γ-secretase cleavage occurs in neurites. Indeed, APP-CTF was, in line with Aβ 42 in our previous study, enriched in the presynapse but absent from the postsynapse. In contrast, full-length AβPP was not detected in either the pre- or the postsynaptic side of the synapse. Furthermore, we observed that endogenously produced and endocytosed Aβ 42 were localized in different compartments. Conclusion: These findings provide critical super-resolved insight into amyloidogenic AβPP processing in primary neurons.

scholarly journals A High-Throughput Screen to Identify Inhibitors of Amyloid β-Protein Precursor Processing

2005 ◽  
Vol 10 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Pancham Bakshi ◽  
Yung-Feng Liao ◽  
Jun Gao ◽  
Jake Ni ◽  
Ross Stein ◽  
...  
Keyword(s):  
High Throughput ◽  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Amyloid Β Protein ◽  
High Throughput Screen ◽  
Transcription Activator ◽  
Protein Precursor ◽  
App Processing ◽  
Chemical Structures ◽  
Β Protein

Cerebral accumulation of the amyloid β-peptide (Aβ) is believed to play a key role in the pathogenesis of Alzheimer’s disease (AD). Because Aβ is produced from the proteolysis of amyloid β-protein precursor (APP) by β-and γ-secretases, these enzymes are considered important drug targets for AD. The authors have developed a luciferase-based reporter system that can identify new molecules that inhibit APP processing in a high-throughput manner. Such molecules can help in understanding the biology of APP and APP processing and in developing new drug prototypes for AD. In this system, APP is fused on its C-terminus with Gal4-VP16, a chimeric yeast-viral transcription activator, and luciferase is under control of the yeast Gal4 promoter. Compounds that modulate the luciferase signal may affect the secretases directly, interact with modifiers of these proteases, or interact with APP directly. The authors successfully interfaced this assay with a high-throughput screen, testing ~60,000 compounds with diverse chemical structures. In principle, this sensitive, specific, and quantitative assay may be useful for identifying both inhibitors and stimulators of APP processing.( Journal of Biomolecular Screening 2005:1-12)

scholarly journals Statins inhibit the dimerization of β-secretase via both isoprenoid- and cholesterol-mediated mechanisms

2006 ◽  
Vol 399 (2) ◽  
pp. 205-214 ◽  
Author(s):  
Richard B. Parsons ◽  
Gemma C. Price ◽  
Joanna K. Farrant ◽  
Daryl Subramaniam ◽  
Jubril Adeagbo-Sheikh ◽  
...  
Keyword(s):  
Cholesterol Biosynthesis ◽  
Active Form ◽  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Hek 293 ◽  
Human Embryonic Kidney Cells ◽  
Cellular Effects ◽  
Aβ Amyloid ◽  
High Doses ◽  
Aβ Production

We have previously reported that protein lipidation in the form of palmitoylation and farnesylation is critical for the production of Aβ (amyloid β-peptide), the dimerization of β-secretase and its trafficking into cholesterol-rich microdomains. As statins influence these lipid modifications in addition to their effects on cholesterol biosynthesis, we have investigated the effects of lovastatin and SIMVA (simvastatin) at a range of concentrations chosen to distinguish different cellular effects on Aβ production and β-secretase structure and its localization in bHEK cells [HEK-293 cells (human embryonic kidney cells) transfected with the Asp-2 gene plus a polyhistidine coding tag] cells. We have compared the changes brought about by statins with those brought about by the palmitoylation inhibitor cerulenin and the farnesyltransferase inhibitor CVFM (Cys-Val-Phe-Met). The statin-mediated reduction in Aβ production correlated with an inhibition of β-secretase dimerization into its more active form at all concentrations of statin investigated. These effects were reversed by the administration of mevalonate, showing that these effects were mediated via 3-hydroxy-3-methylglutaryl-CoA-dependent pathways. At low (1 μM) statin concentrations, reduction in Aβ production and inhibition of β-secretase dimerization were mediated by inhibition of isoprenoid synthesis. At high (>10 μM) concentrations of statins, inhibition of β-secretase palmitoylation occurred, which we demonstrated to be regulated by intracellular cholesterol levels. There was also a concomitant concentration-dependent change in β-secretase subcellular trafficking. Significantly, Aβ release from cells was markedly higher at 50 μM SIMVA than at 1 μM, whereas these concentrations resulted in similar reductions in total Aβ production, suggesting that low-dose statins may be more beneficial than high doses for the therapeutic treatment of Alzheimer's disease.

Processive proteolysis by γ-secretase and the mechanism of Alzheimer’s disease

2012 ◽  
Vol 393 (9) ◽  
pp. 899-905 ◽  
Author(s):  
Michael S. Wolfe
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Transmembrane Domain ◽  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Amyloid Β Protein ◽  
Loss Of Function ◽  
Gain Of Function ◽  
C Terminus ◽  
Secretase Activity

Abstract γ-Secretase is a membrane-embedded protease complex with presenilin as the catalytic component. Cleavage within the transmembrane domain of the amyloid β-protein precursor (APP) by γ-secretase produces the C-terminus of the amyloid β-peptide (Aβ), a proteolytic product prone to aggregation and strongly linked to Alzheimer’s disease (AD). Presenilin mutations are associated with early-onset AD, but their pathogenic mechanisms are unclear. One hypothesis is that these mutations cause AD through a toxic gain of function, changing γ-secretase activity to increase the proportion of 42-residue Aβ over the more soluble 40-residue form. A competing hypothesis is that the mutations cause AD through a loss of function, by reducing γ-secretase activity. However, γ-secretase apparently has two types of activities, an endoproteolytic function that first cuts APP to generate a 48/49-residue form of Aβ, and a carboxypeptidase activity that processively trims these longer Aβ intermediates approximately every three residues to form shorter, secreted forms. Recent studies suggest a resolution of the gain-of-function vs. loss-of-function debate: presenilin mutations may increase the proportion of longer, more aggregation-prone Aβ by specifically decreasing the trimming activity of γ-secretase. That is, the reduction of this particular proteolytic function of presenilin, not its endoproteolytic activity, may lead to the neurotoxic gain of function.

Transcranial Laser Therapy Attenuates Amyloid-β Peptide Neuropathology in Amyloid-β Protein Precursor Transgenic Mice

2011 ◽  
Vol 23 (3) ◽  
pp. 521-535 ◽  
Author(s):  
Luis De Taboada ◽  
Jin Yu ◽  
Salim El-Amouri ◽  
Sebastiano Gattoni-Celli ◽  
Steve Richieri ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Laser Therapy ◽  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Amyloid Β Protein ◽  
Protein Precursor ◽  
Β Protein

Anti-Stroke Chinese Herbal Medicines Inhibit Abnormal Amyloid-β Protein Precursor Processing in Alzheimer’s Disease

2021 ◽  
pp. 1-12
Author(s):  
Yan Tan ◽  
Jiani Zhang ◽  
Ke Yang ◽  
Zihui Xu ◽  
Huawei Zhang ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Herbal Medicines ◽  
Amyloid Β ◽  
Amyloid Β Protein ◽  
Chinese Herbal Medicines ◽  
Protein Precursor ◽  
Chinese Herbal ◽  
Β Protein ◽  
Aβ Production ◽  
Bace1 Activity

Background: Chinese Herbal Medicines (CHMs), as an important and integral part of a larger system of medicine practiced in China, called Traditional Chinese Medicine (TCM), have been used in stroke therapy for centuries. A large body of studies suggest that some Chinese herbs can help reverse cognitive impairment in stroke patients, while whether these herbs also exert therapeutic benefits for Alzheimer’s disease remains to be seen. Objective: To address this issue, we selected four types of CHMs that are commonly prescribed for stroke treatment in clinical practice, namely DengZhanXiXin (D1), TongLuoJiuNao (T2), QingKaiLing (Q3), and HuangQinGan (H4), and tested their effects on amyloid-β protein precursor (AβPP) processing in vitro. Methods: AβPP, β-secretase (BACE1), and 99-amino acid C-terminal fragment of AβPP (C99) stably transfected cells were used for the tests of AβPP processing. The production of Aβ, activity of BACE1, neprilysin (NEP), and γ-secretase were assessed by ELISA, RT-PCR, and western blot. Results: By upregulating BACE1 activity, D1 increased Aβ production whereas decreased the ratio of Aβ 42/Aβ 40; by downregulating BACE1 activity and modulating the expression of γ-secretase, T2 decreased Aβ production and the ratio of Aβ 42/Aβ 40; by downregulating BACE1 activity, Q3 decreased Aβ production; H4 did not change Aβ production due to the simultaneously downregulation of BACE1 and NEP activity. Conclusion: Our study indicates that these four anti-stroke CHMs regulate AβPP processing through different mechanisms. Particularly, T2 with relatively simple components and prominent effect on AβPP processing may be a promising candidate for the treatment of AD.

Novel mutations introduced at the β-site of amyloid β protein precursor enhance the production of amyloid β peptide by BACE1 in vitro and in cells

2005 ◽  
Vol 7 (2) ◽  
pp. 139-148 ◽  
Author(s):  
Xiao-Ping Shi ◽  
Katherine Tugusheva ◽  
James E. Bruce ◽  
Adam Lucka ◽  
Elizabeth Chen-Dodson ◽  
...  
Keyword(s):  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Amyloid Β Protein ◽  
Novel Mutations ◽  
Protein Precursor ◽  
Β Protein ◽  
In Cells

Multicomponent Training Prevents Memory Deficit Related to Amyloid-β Protein-Induced Neurotoxicity

2021 ◽  
pp. 1-12
Author(s):  
Caroline Bitencourt Soares ◽  
Leticia Rossi Daré ◽  
Karine Ramires Lima ◽  
Luiza Freitas Lopes ◽  
Alexandre Garcia dos Santos ◽  
...  
Keyword(s):  
Recognition Memory ◽  
Physical Exercise ◽  
Amyloid Β ◽  
Memory Deficits ◽  
Amyloid Β Peptide ◽  
Amyloid Β Protein ◽  
Β Protein ◽  
Cognitive Exercise ◽  
The Brain

Background: Alzheimer’s disease (AD) is characterized by the accumulation of the amyloid-β peptide in the brain, leading to early oxidative stress and neurotoxicity. It has been suggested that physical exercise could be beneficial in preventing AD, but studies with multicomponent training are scanty. Objective: Verify the effects of multicomponent exercise training to prevent deficits in recognition memory related to Aβ neurotoxicity. Methods: We subjected Wistar rats to multicomponent training (including aerobic and anaerobic physical exercise and cognitive exercise) and then infused amyloid-β peptide into their hippocampus. Results: We show that long-term multicomponent training prevents the amyloid-β-associated neurotoxicity in the hippocampus. It reduces hippocampal lipid peroxidation, restores antioxidant capacity, and increases glutathione levels, finally preventing recognition memory deficits. Conclusion: Multicomponent training avoids memory deficits related to amyloid-β neurotoxicity on an animal model.

scholarly journals Small Molecule Amyloid-β Protein Precursor Processing Modulators Lower Amyloid-β Peptide Levels via cKit Signaling

2019 ◽  
Vol 67 (3) ◽  
pp. 1089-1106 ◽  
Author(s):  
Ci-Di Chen ◽  
Ella Zeldich ◽  
Christina Khodr ◽  
Kaddy Camara ◽  
Tze Yu Tung ◽  
...  
Keyword(s):  
Small Molecule ◽  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Amyloid Β Protein ◽  
Protein Precursor ◽  
Precursor Processing ◽  
Β Protein

Nicotine lowers the secretion of the Alzheimer's amyloid β-protein precursor that contains amyloid β-peptide in rat

2002 ◽  
Vol 4 (5) ◽  
pp. 405-415 ◽  
Author(s):  
Tadanobu Utsuki ◽  
Mohammed Shoaib ◽  
Harold W. Holloway ◽  
Donald K. Ingram ◽  
William C. Wallace ◽  
...  
Keyword(s):  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Amyloid Β Protein ◽  
Protein Precursor ◽  
Β Protein
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