The Experts below are selected from a list of 17379 Experts worldwide ranked by ideXlab platform
Michael S. Wolfe - One of the best experts on this subject based on the ideXlab platform.
-
nicastrin functions to sterically hinder γ Secretase substrate interactions driven by substrate transmembrane domain
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: David M Bolduc, Daniel R Montagna, Yongli Gu, Dennis J Selkoe, Michael S. WolfeAbstract:γ-Secretase is an intramembrane-cleaving protease that processes many type-I integral membrane proteins within the lipid bilayer, an event preceded by shedding of most of the substrate’s ectodomain by α- or β-Secretases. The mechanism by which γ-Secretase selectively recognizes and recruits ectodomain-shed substrates for catalysis remains unclear. In contrast to previous reports that substrate is actively recruited for catalysis when its remaining short ectodomain interacts with the nicastrin component of γ-Secretase, we find that substrate ectodomain is entirely dispensable for cleavage. Instead, γ-Secretase–substrate binding is driven by an apparent tight-binding interaction derived from substrate transmembrane domain, a mechanism in stark contrast to rhomboid—another family of intramembrane-cleaving proteases. Disruption of the nicastrin fold allows for more efficient cleavage of substrates retaining longer ectodomains, indicating that nicastrin actively excludes larger substrates through steric hindrance, thus serving as a molecular gatekeeper for substrate binding and catalysis.
-
presenilins and γ Secretase structure function and role in alzheimer disease
Cold Spring Harbor Perspectives in Medicine, 2012Co-Authors: Bart De Strooper, Takeshi Iwatsubo, Michael S. WolfeAbstract:Presenilins were first discovered as sites of missense mutations responsible for early-onset Alzheimer disease (AD). The encoded multipass membrane proteins were subsequently found to be the catalytic components of γ-Secretases, membrane-embedded aspartyl protease complexes responsible for generating the carboxyl terminus of the amyloid β-protein (Aβ) from the amyloid protein precursor (APP). The protease complex also cleaves a variety of other type I integral membrane proteins, most notably the Notch receptor, signaling from which is involved in many cell differentiation events. Although γ-Secretase is a top target for developing disease-modifying AD therapeutics, interference with Notch signaling should be avoided. Compounds that alter Aβ production by γ-Secretase without affecting Notch proteolysis and signaling have been identified and are currently at various stages in the drug development pipeline.
-
tumor necrosis factor α interleukin 1β and interferon γ stimulate γ Secretase mediated cleavage of amyloid precursor protein through a jnk dependent mapk pathway
Journal of Biological Chemistry, 2004Co-Authors: Yungfeng Liao, Bojeng Wang, Huiting Cheng, Lanhsin Kuo, Michael S. WolfeAbstract:The deposition of the amyloid beta (Abeta) peptide in neuritic plaques plays a critical role in the pathogenesis of Alzheimer's disease (AD). Abeta is generated through the proteolysis of amyloid precursor protein (APP) by the sequential actions of beta- and gamma-Secretases. Although recent evidence has unveiled much about the biochemical identity and characteristics of gamma-Secretase, the mechanism regulating endogenous gamma-Secretase activity remains elusive. To identify possible extracellular signals and associated signaling cascades that could regulate APP proteolysis by gamma-Secretase activity, we have developed a cell-based reporter gene assay by stably cotransfecting HEK293 cells with the Gal4-driven luciferase reporter gene and the Gal4/VP16-tagged C-terminal fragment of APP (C99-GV), the immediate substrate of gamma-Secretase. The cleavage of C99-GV by gamma-Secretase releases the transcription factor that activates luciferase expression, providing a quantitative measurement of gamma-Secretase activity. Using this reporter assay, we have demonstrated that interferon-gamma, interleukin-1beta, and tumor necrosis factor-alpha can specifically stimulate gamma-Secretase activity, concomitant with increased production of Abeta and the intracellular domain of APP (AICD). The gamma-Secretase-dependent cleavage of Notch is also enhanced upon the stimulation of these cytokines. The cytokine-enhanced gamma-Secretase activity can be suppressed by a potent inhibitor of c-Jun N-terminal kinase (JNK). Furthermore, cells transfected with dominant-positive MEKK1, one of the most potent activators of the JNK cascade, exhibit increased gamma-Secretase activity, suggesting that the JNK-dependent mitogen-activated protein kinase pathway could mediate the cytokine-elicited regulation of gamma-Secretase. Our studies provide direct evidence that cytokine-elicited signaling cascades control Abeta production by modulating gamma-Secretase activity.
-
transition state analogue inhibitors of γ Secretase bind directly to presenilin 1
Nature Cell Biology, 2000Co-Authors: William P Esler, Dennis J Selkoe, Taylor W Kimberly, Beth L Ostaszewski, Thekla S Diehl, Chad L Moore, Jui Yi Tsai, Talat Rahmati, Weiming Xia, Michael S. WolfeAbstract:The β-amyloid precursor protein (β-APP), which is involved in the pathogenesis of Alzheimer’s disease, and the Notch receptor, which is responsible for critical signalling events during development, both undergo unusual proteolysis within their transmembrane domains by unknown γ-Secretases. Here we show that an affinity reagent designed to interact with the active site of γ-Secretase binds directly and specifically to heterodimeric forms of presenilins, polytopic proteins that are mutated in hereditary Alzheimer’s and are known mediators of γ-Secretase cleavage of both β-APP and Notch. These results provide evidence that heterodimeric presenilins contain the active site of γ-Secretase, and validate presenilins as principal targets for the design of drugs to treat and prevent Alzheimer’s disease.
-
peptidomimetic probes and molecular modeling suggest that alzheimer s γ Secretase is an intramembrane cleaving aspartyl protease
Biochemistry, 1999Co-Authors: Michael S. Wolfe, Beth L Ostaszewski, Chad L Moore, Talat Rahmati, Weiming Xia, Dartha D Leatherwood, Isaac O Donkor, Dennis J SelkoeAbstract:The amyloid β-protein (Aβ), implicated in the pathogenesis of Alzheimer's disease (AD), is a proteolytic metabolite generated by the sequential action of β- and γ-Secretases on the amyloid precursor protein (APP). The two main forms of Aβ are 40- and 42-amino acid C-terminal variants, Aβ40 and Aβ42. We recently described a difluoro ketone peptidomimetic (1) that blocks Aβ production at the γ-Secretase level [Wolfe, M. S., et al. (1998) J. Med. Chem. 41, 6−9]. Although designed to inhibit Aβ42 production, 1 also effectively blocked Aβ40 formation. Various amino acid changes in 1 still resulted in inhibition of Aβ40 and Aβ42 production, suggesting relatively loose sequence specificity by γ-Secretase. The alcohol counterparts of selected difluoro ketones also lowered Aβ levels, indicating that the ketone carbonyl is not essential for activity and suggesting that these compounds inhibit an aspartyl protease. Selected compounds inhibited the aspartyl protease cathepsin D but not the cysteine protease calpain, ...
Ishrut Hussain - One of the best experts on this subject based on the ideXlab platform.
-
characterization of the ectodomain shedding of the β site amyloid precursor protein cleaving enzyme 1 bace1
Journal of Biological Chemistry, 2003Co-Authors: Ishrut Hussain, Andrew Faller, Julie Hawkins, Aarti Shikotra, David R Riddell, Colin DingwallAbstract:Abstract Generation of the amyloid peptide through proteolytic processing of the amyloid precursor protein by β- and γ-Secretases is central to the etiology of Alzheimer's disease. β-Secretase, known more widely as the β-site amyloid precursor protein cleaving enzyme 1 (BACE1), has been identified as a transmembrane aspartic proteinase, and its ectodomain has been reported to be cleaved and secreted from cells in a soluble form. The extracellular domains of many diverse proteins are known to be cleaved and secreted from cells by a process known as ectodomain shedding. Here we confirm that the ectodomain of BACE1 is secreted from cells and that this processing is up-regulated by agents that activate protein kinase C. A metalloproteinase is involved in the cleavage of BACE1 as hydroxamic acid-based metalloproteinase inhibitors abolish the release of shed BACE1. Using potent and selective inhibitors, we demonstrate that ADAM10 is a strong candidate for the BACE1 sheddase. In addition, we show that the BACE1 sheddase is distinct from α-Secretase and, importantly, that inhibition of BACE1 shedding does not influence amyloid precursor protein processing at the β-site.
-
asp1 bace2 cleaves the amyloid precursor protein at the beta Secretase site
Molecular and Cellular Neuroscience, 2000Co-Authors: Ishrut Hussain, David J. Powell, Thomas D. Meek, Conrad Gerald Chapman, David R. Howlett, G A Chapman, L Gilmour, Paul R Murdock, Klaus Schneider, S J RatcliffeAbstract:Abstract Sequential proteolytic processing of the Amyloid Precursor Protein (APP) by β- and γ-Secretases generates the 4-kDa amyloid (Aβ) peptide, a key component of the amyloid plaques seen in Alzheimer's disease (AD). We and others have recently reported the identification and characterisation of an aspartic proteinase, Asp2 (BACE), as β-Secretase. Here we describe the characterization of a second highly related aspartic proteinase, Asp1 as a second β-Secretase candidate. Asp1 is expressed in brain as detected at the mRNA level and at the protein level. Transient expression of Asp1 in APP-expressing cells results in an increase in the level of β-Secretase-derived soluble APP and the corresponding carboxy-terminal fragment. Paradoxically there is a decrease in the level of soluble Aβ secreted from the cells. Asp1 colocalizes with APP in the Golgi/endoplasmic reticulum compartments of cultured cells. Asp1, when expressed as an Fc fusion protein (Asp1-Fc), has the N-terminal sequence ALEP… , indicating that it has lost the prodomain. Asp1-Fc exhibits β-Secretase activity by cleaving both wild-type and Swedish variant (KM/NL) APP peptides at the β-Secretase site.
-
Identification of a novel aspartic protease (Asp 2) as beta-Secretase.
Molecular and Cellular Neuroscience, 1999Co-Authors: Ishrut Hussain, David J. Powell, Thomas D. Meek, Conrad Gerald Chapman, Israel S. Gloger, Kay Murphy, Christopher Southan, David R. Howlett, Dominic M. RyanAbstract:The Alzheimer's disease beta-amyloid peptide (Abeta) is produced by excision from the type 1 integral membrane glycoprotein amyloid precursor protein (APP) by the sequential actions of beta- and then gamma-Secretases. Here we report that Asp 2, a novel transmembrane aspartic protease, has the key activities expected of beta-Secretase. Transient expression of Asp 2 in cells expressing APP causes an increase in the secretion of the N-terminal fragment of APP and an increase in the cell-associated C-terminal beta-Secretase APP fragment. Mutation of either of the putative catalytic aspartyl residues in Asp 2 abrogates the production of the fragments characteristic of cleavage at the beta-Secretase site. The enzyme is present in normal and Alzheimer's disease (AD) brain and is also found in cell lines known to produce Abeta. Asp 2 localizes to the Golgi/endoplasmic reticulum in transfected cells and shows clear colocalization with APP in cells stably expressing the 751-amino-acid isoform of APP.
-
identification of a novel aspartic protease asp 2 as beta Secretase
Molecular and Cellular Neuroscience, 1999Co-Authors: Ishrut Hussain, David J. Powell, Thomas D. Meek, Conrad Gerald Chapman, Israel S. Gloger, Kay Murphy, Dominic M. Ryan, Christopher Southan, David R. Howlett, Trudi S SmithAbstract:Abstract The Alzheimer's disease β-amyloid peptide (Aβ) is produced by excision from the type 1 integral membrane glycoprotein amyloid precursor protein (APP) by the sequential actions of β- and then γ-Secretases. Here we report that Asp 2, a novel transmembrane aspartic protease, has the key activities expected of β-Secretase. Transient expression of Asp 2 in cells expressing APP causes an increase in the secretion of the N-terminal fragment of APP and an increase in the cell-associated C-terminal β-Secretase APP fragment. Mutation of either of the putative catalytic aspartyl residues in Asp 2 abrogates the production of the fragments characteristic of cleavage at the β-Secretase site. The enzyme is present in normal and Alzheimer's disease (AD) brain and is also found in cell lines known to produce Aβ. Asp 2 localizes to the Golgi/endoplasmic reticulum in transfected cells and shows clear colocalization with APP in cells stably expressing the 751-amino-acid isoform of APP.
Joachim Kirsch - One of the best experts on this subject based on the ideXlab platform.
-
app anterograde transport requires rab3a gtpase activity for assembly of the transport vesicle
The Journal of Neuroscience, 2009Co-Authors: Anita Szodorai, Ulrike Engel, Ayuko Sakane, Takuya Sasaki, Yoshimi Takai, Joachim KirschAbstract:The amyloid precursor protein (APP) is anterogradely transported by conventional kinesin in a distinct transport vesicle, but both the biochemical composition of such a vesicle and the specific kinesin-1 motor responsible for transport are poorly defined. APP may be sequentially cleaved by β- and γ-Secretases leading to accumulation of β-amyloid (Aβ) peptides in brains of Alzheimer's disease patients, whereas cleavage of APP by α-Secretases prevents Aβ generation. Here, we demonstrate by time-lapse analysis and immunoisolations that APP is a cargo of a vesicle containing the kinesin heavy chain isoform kinesin-1C, the small GTPase Rab3A, and a specific subset of presynaptic protein components. Moreover, we report that assembly of kinesin-1C and APP in this vesicle type requires Rab3A GTPase activity. Finally, we show cleavage of APP in transport vesicles by α-Secretase activity, likely mediated by ADAM10. Together, these data indicate that maturation of APP transport vesicles, including recruitment of conventional kinesin, requires Rab3 GTPase activity.
-
APP Anterograde Transport Requires Rab3A GTPase Activity for Assembly of the Transport Vesicle
The Journal of neuroscience : the official journal of the Society for Neuroscience, 2009Co-Authors: Anita Szodorai, Ulrike Engel, Ayuko Sakane, Takuya Sasaki, Yoshimi Takai, Joachim Kirsch, Yung Hui Kuan, Silke Hunzelmann, Ulrike Müller, Konrad BeyreutherAbstract:The amyloid precursor protein (APP) is anterogradely transported by conventional kinesin in a distinct transport vesicle, but both the biochemical composition of such a vesicle and the specific kinesin-1 motor responsible for transport are poorly defined. APP may be sequentially cleaved by beta- and gamma-Secretases leading to accumulation of beta-amyloid (Abeta) peptides in brains of Alzheimer's disease patients, whereas cleavage of APP by alpha-Secretases prevents Abeta generation. Here, we demonstrate by time-lapse analysis and immunoisolations that APP is a cargo of a vesicle containing the kinesin heavy chain isoform kinesin-1C, the small GTPase Rab3A, and a specific subset of presynaptic protein components. Moreover, we report that assembly of kinesin-1C and APP in this vesicle type requires Rab3A GTPase activity. Finally, we show cleavage of APP in transport vesicles by alpha-Secretase activity, likely mediated by ADAM10. Together, these data indicate that maturation of APP transport vesicles, including recruitment of conventional kinesin, requires Rab3 GTPase activity.
Jose Lopez A De Castro - One of the best experts on this subject based on the ideXlab platform.
-
l 685 458 an aspartyl protease transition state mimic is a potent inhibitor of amyloid β protein precursor γ Secretase activity
Biochemistry, 2000Co-Authors: Mark S Shearman, Dirk Beher, Earl E Clarke, Huw D Lewis, Tim Harrison, Peter W Hunt, Alan Nadin, Adrian L Smith, Graeme Irvine Stevenson, Jose Lopez A De CastroAbstract:Progressive cerebral amyloid β-protein (Aβ) deposition is believed to play a central role in the pathogenesis of Alzheimer's disease (AD). Elevated levels of Aβ(42) peptide formation have been linked to early-onset familial AD-causing gene mutations in the amyloid β-protein precursor (AβPP) and the presenilins. Sequential cleavage of AβPP by the β- and γ-Secretases generates the N- and C-termini of the Aβ peptide, making both the β- and γ-Secretase enzymes potential therapeutic targets for AD. The identity of the AβPP γ-Secretase and the mechanism by which the C-termini of Aβ are formed remain uncertain, although it has been suggested that the presenilins themselves are novel intramembrane-cleaving γ-Secretases of the aspartyl protease class [Wolfe, M. S., Xia, W., Ostaszewski, B. L., Diehl, T. S., Kimberly, W. T., and Selkoe, D. J. (1999) Nature 398, 513−517]. In this study we report the identification of L-685,458 as a structurally novel inhibitor of AβPP γ-Secretase activity, with a similar potency for...
-
l 685 458 an aspartyl protease transition state mimic is a potent inhibitor of amyloid beta protein precursor gamma Secretase activity
Biochemistry, 2000Co-Authors: Mark S Shearman, Dirk Beher, Earl E Clarke, Huw D Lewis, Peter W Hunt, Alan Nadin, Adrian L Smith, Graeme Irvine Stevenson, Timothy Harrison, Jose Lopez A De CastroAbstract:Progressive cerebral amyloid β-protein (Aβ) deposition is believed to play a central role in the pathogenesis of Alzheimer's disease (AD). Elevated levels of Aβ(42) peptide formation have been linked to early-onset familial AD-causing gene mutations in the amyloid β-protein precursor (AβPP) and the presenilins. Sequential cleavage of AβPP by the β- and γ-Secretases generates the N- and C-termini of the Aβ peptide, making both the β- and γ-Secretase enzymes potential therapeutic targets for AD. The identity of the AβPP γ-Secretase and the mechanism by which the C-termini of Aβ are formed remain uncertain, although it has been suggested that the presenilins themselves are novel intramembrane-cleaving γ-Secretases of the aspartyl protease class [Wolfe, M. S., Xia, W., Ostaszewski, B. L., Diehl, T. S., Kimberly, W. T., and Selkoe, D. J. (1999) Nature 398, 513−517]. In this study we report the identification of L-685,458 as a structurally novel inhibitor of AβPP γ-Secretase activity, with a similar potency for...
Alan Nadin - One of the best experts on this subject based on the ideXlab platform.
-
l 685 458 an aspartyl protease transition state mimic is a potent inhibitor of amyloid β protein precursor γ Secretase activity
Biochemistry, 2000Co-Authors: Mark S Shearman, Dirk Beher, Earl E Clarke, Huw D Lewis, Tim Harrison, Peter W Hunt, Alan Nadin, Adrian L Smith, Graeme Irvine Stevenson, Jose Lopez A De CastroAbstract:Progressive cerebral amyloid β-protein (Aβ) deposition is believed to play a central role in the pathogenesis of Alzheimer's disease (AD). Elevated levels of Aβ(42) peptide formation have been linked to early-onset familial AD-causing gene mutations in the amyloid β-protein precursor (AβPP) and the presenilins. Sequential cleavage of AβPP by the β- and γ-Secretases generates the N- and C-termini of the Aβ peptide, making both the β- and γ-Secretase enzymes potential therapeutic targets for AD. The identity of the AβPP γ-Secretase and the mechanism by which the C-termini of Aβ are formed remain uncertain, although it has been suggested that the presenilins themselves are novel intramembrane-cleaving γ-Secretases of the aspartyl protease class [Wolfe, M. S., Xia, W., Ostaszewski, B. L., Diehl, T. S., Kimberly, W. T., and Selkoe, D. J. (1999) Nature 398, 513−517]. In this study we report the identification of L-685,458 as a structurally novel inhibitor of AβPP γ-Secretase activity, with a similar potency for...
-
l 685 458 an aspartyl protease transition state mimic is a potent inhibitor of amyloid beta protein precursor gamma Secretase activity
Biochemistry, 2000Co-Authors: Mark S Shearman, Dirk Beher, Earl E Clarke, Huw D Lewis, Peter W Hunt, Alan Nadin, Adrian L Smith, Graeme Irvine Stevenson, Timothy Harrison, Jose Lopez A De CastroAbstract:Progressive cerebral amyloid β-protein (Aβ) deposition is believed to play a central role in the pathogenesis of Alzheimer's disease (AD). Elevated levels of Aβ(42) peptide formation have been linked to early-onset familial AD-causing gene mutations in the amyloid β-protein precursor (AβPP) and the presenilins. Sequential cleavage of AβPP by the β- and γ-Secretases generates the N- and C-termini of the Aβ peptide, making both the β- and γ-Secretase enzymes potential therapeutic targets for AD. The identity of the AβPP γ-Secretase and the mechanism by which the C-termini of Aβ are formed remain uncertain, although it has been suggested that the presenilins themselves are novel intramembrane-cleaving γ-Secretases of the aspartyl protease class [Wolfe, M. S., Xia, W., Ostaszewski, B. L., Diehl, T. S., Kimberly, W. T., and Selkoe, D. J. (1999) Nature 398, 513−517]. In this study we report the identification of L-685,458 as a structurally novel inhibitor of AβPP γ-Secretase activity, with a similar potency for...
-
photoactivated γ Secretase inhibitors directed to the active site covalently label presenilin 1
Nature, 2000Co-Authors: Mingtain Lai, Alan Nadin, Timothy Harrison, Qian Huang, Jose L Castro, Jillian Dimuziomower, Colin Lellis, Joseph G Neduvelil, Bruce R Register, Mohinder K SardanaAbstract:Cleavage of amyloid precursor protein (APP) by the β- and γ-Secretases generates the amino and carboxy termini, respectively, of the Aβ amyloidogenic peptides Aβ40 and Aβ42—the major constituents of the amyloid plaques in the brain parenchyma of Alzheimer's disease patients1. There is evidence that the polytopic membrane-spanning proteins, presenilin 1 and 2 (PS1 and PS2), are important determinants of γ-Secretase activity: mutations in PS1 and PS2 that are associated with early-onset familial Alzheimer's disease2,3 increase the production of Aβ42 (refs 4,5,6), the more amyloidogenic peptide; γ-Secretase activity is reduced in neuronal cultures derived from PS1-deficient mouse embryos7; and directed mutagenesis of two conserved aspartates in transmembrane segments of PS1 inactivates the ability of γ-Secretase to catalyse processing of APP within its transmembrane domain8. It is unknown, however, whether PS1 (which has little or no homology to any known aspartyl protease) is itself a transmembrane aspartyl protease or a γ-Secretase cofactor, or helps to colocalize γ-Secretase and APP. Here we report photoaffinity labelling of PS1 (and PS2) by potent γ-Secretase inhibitors that were designed to function as transition state analogue inhibitors directed to the active site of an aspartyl protease. This observation indicates that PS1 (and PS2) may contain the active site of γ-Secretase. Interestingly, the intact, single-chain form of wild-type PS1 is not labelled by an active-site-directed photoaffinity probe, suggesting that intact wild-type PS1 may be an aspartyl protease zymogen.
-
photoactivated γ Secretase inhibitors directed to the active site covalently label presenilin 1
Nature, 2000Co-Authors: Mingtain Lai, Alan Nadin, Qian Huang, Jose L Castro, Jillian Dimuziomower, Colin Lellis, Joseph G Neduvelil, T Harrison, R B Register, Mohinder K SardanaAbstract:Cleavage of amyloid precursor protein (APP) by the beta- and gamma-Secretases generates the amino and carboxy termini, respectively, of the A beta amyloidogenic peptides A beta40 and A beta42--the major constituents of the amyloid plaques in the brain parenchyma of Alzheimer's disease patients. There is evidence that the polytopic membrane-spanning proteins, presenilin 1 and 2 (PS1 and PS2), are important determinants of gamma-Secretase activity: mutations in PS1 and PS2 that are associated with early-onset familial Alzheimer's disease increase the production of A beta42 (refs 4-6), the more amyloidogenic peptide; gamma-Secretase activity is reduced in neuronal cultures derived from PS1-deficient mouse embryos; and directed mutagenesis of two conserved aspartates in transmembrane segments of PS1 inactivates the ability of gamma-Secretase to catalyse processing of APP within its transmembrane domain. It is unknown, however, whether PS1 (which has little or no homology to any known aspartyl protease) is itself a transmembrane aspartyl protease or a gamma-Secretase cofactor, or helps to colocalize gamma-Secretase and APP. Here we report photoaffinity labelling of PS1 (and PS2) by potent gamma-Secretase inhibitors that were designed to function as transition state analogue inhibitors directed to the active site of an aspartyl protease. This observation indicates that PS1 (and PS2) may contain the active site of gamma-Secretase. Interestingly, the intact, single-chain form of wild-type PS1 is not labelled by an active-site-directed photoaffinity probe, suggesting that intact wild-type PS1 may be an aspartyl protease zymogen.
