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Presenilin

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https://www.readbyqxmd.com/read/28096459/zinc-and-copper-differentially-modulate-amyloid-precursor-protein-processing-by-%C3%AE-secretase-and-amyloid-%C3%AE-peptide-production
#1
Hermeto Gerber, Fang Wu, Mitko Dimitrov, Guillermo M Garcia Osuna, Patrick C Fraering
Recent evidence suggests involvement of biometal homeostasis in the pathological mechanisms in Alzheimer's disease (AD). For example, increased intracellular copper or zinc has been linked to a reduction in secreted levels of the AD-causing amyloid-β peptide (Aβ). However, little is known about whether these biometals modulate the generation of Aβ. In the present study, we demonstrate in both cell-free and cell-based assays that zinc and copper regulate Aβ production by distinct molecular mechanisms affecting the processing by γ-secretase of its Aβ precursor protein substrate APP-C99...
January 17, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28068334/two-paralogous-tetraspanins-tsp-12-and-tsp-14-function-with-the-adam10-metalloprotease-sup-17-to-promote-bmp-signaling-in-caenorhabditis-elegans
#2
Lin Wang, Zhiyu Liu, Herong Shi, Jun Liu
The highly conserved bone morphogenetic protein (BMP) signaling pathway regulates many developmental and homeostatic processes. While the core components of the BMP pathway have been well studied, much research is needed for understanding the mechanisms involved in the precise spatiotemporal control of BMP signaling in vivo. Here, we provide evidence that two paralogous and evolutionarily conserved tetraspanins, TSP-12 and TSP-14, function redundantly to promote BMP signaling in C. elegans. We further show that the ADAM10 (a disintegrin and metalloprotease 10) ortholog SUP-17 also functions to promote BMP signaling, and that TSP-12 can bind to and promote the cell surface localization of SUP-17...
January 9, 2017: PLoS Genetics
https://www.readbyqxmd.com/read/28065657/mapping-the-binding-site-of-bms-708163-on-%C3%AE-secretase-with-cleavable-photoprobes
#3
Natalya Gertsik, Christopher W Am Ende, Kieran F Geoghegan, Chuong Nguyen, Paramita Mukherjee, Scot Mente, Uthpala Seneviratne, Douglas S Johnson, Yue-Ming Li
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...
January 19, 2017: Cell Chemical Biology
https://www.readbyqxmd.com/read/28065273/screening-and-characterization-strategies-for-nanobodies-targeting-membrane-proteins
#4
S Veugelen, M Dewilde, B De Strooper, L Chávez-Gutiérrez
The study of membrane protein function and structure requires their successful detection, expression, solubilization, and/or reconstitution, which poses a challenging task and relies on the availability of suitable tools. Several research groups have successfully applied Nanobodies in the purification, as well as the functional and structural characterization of membrane proteins. Nanobodies are small, single-chain antibody fragments originating from camelids presenting on average a longer CDR3 which enables them to bind in cavities and clefts (such as active and allosteric sites)...
2017: Methods in Enzymology
https://www.readbyqxmd.com/read/28065263/probing-the-structure-and-function-relationships-of-presenilin-by-substituted-cysteine-accessibility-method
#5
T Tomita
Presenilin is a catalytic subunit of γ-secretase, which hydrolyzes several transmembrane proteins within the lipid bilayer, together with binding cofactors such as nicastrin, Aph-1, and Pen-2. However, the structural basis as well as molecular mechanism of this unusual proteolytic process remains unknown. We have analyzed the structure and function relationships of presenilin using the substituted-cysteine accessibility method (SCAM), which enables identification of the hydrophilic environment by the accessibility of sulfhydryl reagents to cysteine residues introduced at a desired position...
2017: Methods in Enzymology
https://www.readbyqxmd.com/read/28065261/expression-purification-and-enzymatic-characterization-of-intramembrane-proteases
#6
R Zhou, Y Shi, G Yang
Intramembrane proteases catalyze peptide bond hydrolysis in the lipid bilayer and play a key role in numerous cellular processes. These integral membrane enzymes consist of four classes: site-2 protease (S2P), rhomboid serine protease, Rce1-type glutamyl protease, and aspartyl protease exemplified by presenilin and signal peptide peptidase (SPP). Structural elucidation of these enzymes is important for mechanistic understanding of their functions, particularly their roles in cell signaling and debilitating diseases such as Parkinson's disease and Alzheimer's disease...
2017: Methods in Enzymology
https://www.readbyqxmd.com/read/28061464/met-receptor-variant-r970c-favors-calpain-dependent-generation-of-a-fragment-promoting-epithelial-cell-scattering
#7
Rémi Montagne, Anne Baranzelli, Ghaffar Muharram, Leroy Catherine, Marie Lesaffre, Audrey Vinchent, Zoulika Kherrouche, Elisabeth Werkmeister, Alexis B Cortot, David Tulasne
The receptor tyrosine kinase MET and its ligand, the hepatocyte growth factor, are essential to embryonic development, whereas deregulation of MET signaling is associated with tumorigenesis leading to various cancers, including lung carcinoma. Mutations in the MET kinase domain lead to constitutive kinase activity and are associated with tumorigenesis. In lung cancer, however, some mutations are found in the juxtamembrane domain, and their functional consequences are unknown. Because the juxtamembrane domain of MET is targeted by several proteolytic cleavages, involved in its degradation during cell death or under steady-state conditions, we evaluated the influence of these mutations on the MET proteolytic cleavages...
January 4, 2017: Oncotarget
https://www.readbyqxmd.com/read/28053619/overexpression-of-n141i-ps2-increases-%C3%AE-secretase-activity-through-up-regulation-of-presenilin-and-pen-2-in-brain-mitochondria-of-nse-hps2m-transgenic-mice
#8
Woo Bin Yun, Jin Ju Park, Ji Eun Kim, Ji Eun Sung, Hyun Ah Lee, Jae Ho Lee, Chang Jun Bae, Dae Youn Hwang
Alzheimer's disease (AD) is known to induce alterations of mitochondrial function such as elevation of oxidative stress and activation of apopotosis. The aim of this study was to investigate the effects of human Presenilin 2 mutant (hPS2m) overexpression on the γ-secretase complex in the mitochondrial fraction. To achieve this, alterations of γ-secretase complex expression and activity were detected in the mitochondrial fraction derived from brains of NSE/hPS2m Tg mice and Non-Tg mice. Herein, the following were observed: i) overexpression of the hPS2m gene significantly up-regulated the deposition of Aβ-42 peptides in the hippocampus and cortex of brain, ii) overexpression of hPS2m protein induced alterations of γ-secretase components such as main component protein and activator protein but not stabilization-related proteins, iii) changes in γ-secretase components induced by overexpression of hPS2m protein up-regulated γ-secretase activity in the mitochondrial fraction, and iv) elevation of γ-secretase activity induced production of Aβ-42 peptides in the mitochondrial fraction...
December 2016: Laboratory Animal Research
https://www.readbyqxmd.com/read/28034848/regulated-intramembrane-proteolysis-of-the-axl-receptor-kinase-generates-an-intracellular-domain-that-localizes-in-the-nucleus-of-cancer-cells
#9
Yinzhong Lu, Jun Wan, Zhifeng Yang, Xiling Lei, Qi Niu, Lanxin Jiang, Willemijn M Passtoors, Aiping Zang, Patrick C Fraering, Fang Wu
Deregulation of the TAM (TYRO3, AXL, and MERTK) family of receptor tyrosine kinases (RTKs) has recently been demonstrated to predominately promote survival and chemoresistance of cancer cells. Intramembrane proteolysis mediated by presenilin/γ-secretase is known to regulate the homeostasis of some RTKs. In the present study, we demonstrate that AXL, but not TYRO3 or MERTK, is efficiently and sequentially cleaved by α- and γ-secretases in various types of cancer cell lines. Proteolytic processing of AXL redirected signaling toward a secretase-mediated pathway, away from the classic, well-known, ligand-dependent canonical RTK signaling pathway...
December 29, 2016: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
https://www.readbyqxmd.com/read/28025335/caspneurod-a-knowledgebase-of-predicted-caspase-cleavage-sites-in-human-proteins-related-to-neurodegenerative-diseases
#10
Sonu Kumar, Piotr Cieplak
BACKGROUND: A variety of neurodegenerative diseases (NDs) have been associated with deregulated caspase activation that leads to neuronal death. Caspases appear to be involved in the molecular pathology of NDs by directly cleaving important proteins. For instance, several proteins involved in Alzheimer's disease, including β-amyloid precursor protein (APP) and presenilins, are known to be cleaved by caspases. Therefore, cell death pathway may play a central role in many neurological diseases, and targeting the important proteins that control the cell survival and death may potentially represent a therapeutic approach for chronic neurodegenerative disorders...
2016: Database: the Journal of Biological Databases and Curation
https://www.readbyqxmd.com/read/27987381/hypoxia-ischemia-activate-processing-of-amyloid-precursor-protein-impact-of-vascular-dysfunction-in-the-pathogenesis-of-alzheimer-s-disease
#11
REVIEW
Antero Salminen, Anu Kauppinen, Kai Kaarniranta
Alzheimer's disease (AD) is associated with deficiencies in cerebrovascular functions, e.g. reduced cerebral blood flow and capillary amyloid angiopathy, both of which are evident during the early phase of AD, thus local hypoxia/ischemia could augment the pathogenesis of AD. There is abundant literature revealing that exposures to hypoxia/ischemia increase the amyloidogenic processing of amyloid-β precursor protein (APP) leading to the accumulation of amyloid-β peptides in brain. This hypoxia-induced response has been attributed to a significant increase in the activities of β- and γ-secretases, whereas α-secretase activity decreases in hypoxia...
December 17, 2016: Journal of Neurochemistry
https://www.readbyqxmd.com/read/27932977/human-neural-stem-cell-transplantation-rescues-cognitive-defects-in-app-ps1-model-of-alzheimer-s-disease-by-enhancing-neuronal-connectivity-and-metabolic-activity
#12
Xueyuan Li, Hua Zhu, Xicai Sun, Fuxing Zuo, Jianfeng Lei, Zhanjing Wang, Xinjie Bao, Renzhi Wang
Alzheimer's disease (AD), the most frequent type of dementia, is featured by Aβ pathology, neural degeneration and cognitive decline. To date, there is no cure for this disease. Neural stem cell (NSC) transplantation provides new promise for treating AD. Many studies report that intra-hippocampal transplantation of murine NSCs improved cognition in rodents with AD by alleviating neurodegeneration via neuronal complement or replacement. However, few reports examined the potential of human NSC transplantation for AD...
2016: Frontiers in Aging Neuroscience
https://www.readbyqxmd.com/read/27930341/analysis-of-138-pathogenic-mutations-in-presenilin-1-on-the-in-vitro-production-of-a%C3%AE-42-and-a%C3%AE-40-peptides-by-%C3%AE-secretase
#13
Linfeng Sun, Rui Zhou, Guanghui Yang, Yigong Shi
A hallmark of Alzheimer's disease (AD) is the aggregation of β-amyloid peptides (Aβ) into amyloid plaques in patient brain. Cleavage of amyloid precursor protein (APP) by the intramembrane protease γ-secretase produces Aβ of varying lengths, of which longer peptides such as Aβ42 are thought to be more harmful. Increased ratios of longer Aβs over shorter ones, exemplified by the ratio of Aβ42 over Aβ40, may lead to formation of amyloid plaques and consequent development of AD. In this study, we analyzed 138 reported mutations in human presenilin-1 (PS1) by individually reconstituting the mutant PS1 proteins into anterior-pharynx-defective protein 1 (APH-1)aL-containing γ-secretases and examining their abilities to produce Aβ42 and Aβ40 in vitro...
December 5, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27928512/extracellular-vesicle-associated-a%C3%AE-mediates-trans-neuronal-bioenergetic-and-ca-2-handling-deficits-in-alzheimer-s-disease-models
#14
Erez Eitan, Emmette R Hutchison, Krisztina Marosi, James Comotto, Maja Mustapic, Saket M Nigam, Caitlin Suire, Chinmoyee Maharana, Gregory A Jicha, Dong Liu, Vasiliki Machairaki, Kenneth W Witwer, Dimitrios Kapogiannis, Mark P Mattson
Alzheimer's Disease (AD) is an age-related neurodegenerative disorder in which aggregation-prone neurotoxic amyloid β-peptide (Aβ) accumulates in the brain. Extracellular vesicles (EVs) are small 50-150 nanometer membrane vesicles that have recently been implicated in the prion-like spread of self-aggregating proteins. Here we report that EVs isolated from AD patient CSF and plasma, from the plasma of two AD mouse models, and from the medium of neural cells expressing familial AD presenilin 1 mutations, destabilize neuronal Ca(2+) homeostasis, impair mitochondrial function, and sensitize neurons to excitotoxicity...
2016: NPJ Aging and Mechanisms of Disease
https://www.readbyqxmd.com/read/27911305/nitrosylation-of-vesicular-transporters-in-brain-of-amyloid-precursor-protein-presenilin-1-double-transgenic-mice
#15
Ying Wang, Zhu Zhou, Hua Tan, Shenghua Zhu, Yiran Wang, Yingxia Sun, Xin-Min Li, Jun-Feng Wang
Nitric oxide can attack thiol groups of cysteine residues in proteins and induce protein cysteine S-nitrosylation. Cholinergic and glutamatergic systems are dysregulated in Alzheimer's disease. Vesicular acetylcholine transporter (VAChT) and vesicular glutamate transporter 1 (VGLUT1) are important in packaging acetylcholine and glutamate into vesicles, which is an important step for neurotransmission. Previously we found that VAChT and VGLUT1 can be nitrosylated and that S-nitrosylation of these transporters inhibits vesicular uptake of acetylcholine and glutamate...
2017: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/27908425/copper-accumulation-in-rodent-brain-astrocytes-a-species-difference
#16
Brendan Sullivan, Gregory Robison, Yulia Pushkar, John K Young, Kebreten F Manaye
Changes in Cu homeostasis have been implicated in multiple neurodegenerative diseases. Factors controlling and regulating the distribution of Cu in the brain remain largely unknown. We have previously reported that a sub-set of astrocytes in the subventricular zone (SVZ) contain Cu-rich aggregates. Here we expand previous studies with detailed X-ray fluorescent imaging (XRF) analysis of the additional brain areas of hippocampus (HP) and rostral migratory stream (RMS). We also use conventional DAB (3,3'-diaminobenzidine) staining which accesses both peroxidase and pseudo-peroxidase activities...
January 2017: Journal of Trace Elements in Medicine and Biology
https://www.readbyqxmd.com/read/27904493/beta-2-adrenergic-receptor-activation-enhances-neurogenesis-in-alzheimer-s-disease-mice
#17
Gao-Shang Chai, Yang-Yang Wang, Amina Yasheng, Peng Zhao
Impaired hippocampal neurogenesis is one of the early pathological features of Alzheimer's disease. Enhancing adult hippocampal neurogenesis has been pursued as a potential therapeutic strategy for Alzheimer's disease. Recent studies have demonstrated that environmental novelty activates β2-adrenergic signaling and prevents the memory impairment induced by amyloid-β oligomers. Here, we hypothesized that β2-adrenoceptor activation would enhance neurogenesis and ameliorate memory deficits in Alzheimer's disease...
October 2016: Neural Regeneration Research
https://www.readbyqxmd.com/read/27889678/early-hippocampal-hyperexcitability-in-ps2app-mice-role-of-mutant-ps2-and-app
#18
Roberto Fontana, Mario Agostini, Emanuele Murana, Mufti Mahmud, Elena Scremin, Maria Rubega, Giovanni Sparacino, Stefano Vassanelli, Cristina Fasolato
Alterations of brain network activity are observable in Alzheimer's disease (AD) together with the occurrence of mild cognitive impairment, before overt pathology. However, in humans as well in AD mouse models, identification of early biomarkers of network dysfunction is still at its beginning. We performed in vivo recordings of local field potential activity in the dentate gyrus of PS2APP mice expressing the human amyloid precursor protein (APP) Swedish mutation and the presenilin-2 (PS2) N141I. From a frequency-domain analysis, we uncovered network hyper-synchronicity as early as 3 months, when intracellular accumulation of amyloid beta was also observable...
February 2017: Neurobiology of Aging
https://www.readbyqxmd.com/read/27881772/store-operated-calcium-channel-complex-in-postsynaptic-spines-a-new-therapeutic-target-for-alzheimer-s-disease-treatment
#19
Hua Zhang, Suya Sun, Lili Wu, Ekaterina Pchitskaya, Olga Zakharova, Klementina Fon Tacer, Ilya Bezprozvanny
: Mushroom dendritic spine structures are essential for memory storage and the loss of mushroom spines may explain memory defects in aging and Alzheimer's disease (AD). The stability of mushroom spines depends on stromal interaction molecule 2 (STIM2)-mediated neuronal-store-operated Ca(2+) influx (nSOC) pathway, which is compromised in AD mouse models, in aging neurons, and in sporadic AD patients. Here, we demonstrate that the Transient Receptor Potential Canonical 6 (TRPC6) and Orai2 channels form a STIM2-regulated nSOC Ca(2+) channel complex in hippocampal mushroom spines...
November 23, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/27875990/inverse-relationship-between-alzheimer-s-disease-and-cancer-and-other-factors-contributing-to-alzheimer-s-disease-a-systematic-review
#20
REVIEW
Ovais Shafi
BACKGROUND: The AD etiology is yet not properly known. Interactions among environmental factors, multiple susceptibility genes and aging, contribute to AD. This study investigates the factors that play role in causing AD and how changes in cellular pathways contribute to AD. METHODS: PUBMED database, MEDLINE database and Google Scholar were searched with no date restrictions for published articles involving cellular pathways with roles in cancers, cell survival, growth, proliferation, development, aging, and also contributing to Alzheimer's disease...
November 22, 2016: BMC Neurology
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