Alzheimer Disease: Yu G

Sephton CF, Yu G. · No affiliation provided · Arch Neurol. · Pubmed #18625853 No free full text.

This publication has no abstract.

Dries DR, Yu G. · Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA. · Curr Alzheimer Res. · Pubmed #18393798 links to  free full text

Abstract: In this review, we discuss the biology of gamma-secretase, an enigmatic enzyme complex that is responsible for the generation of the amyloid-beta peptide that constitutes the amyloid plaques of Alzheimer's disease. We begin with a brief review on the processing of the amyloid precursor protein and a brief discussion on the family of enzymes involved in regulated intramembrane proteolysis, of which gamma-secretase is a member. We then identify the four major components of the gamma-secretase complex - presenilin, nicastrin, Aph-1, and Pen-2 - with a focus on the identification of each and the role that each plays in the maturation and activity of the complex. We also discuss two new proteins that may play a role in modulating the assembly and activity of the gamma-secretase complex. Next, we summarize the known subcellular locations of each gamma-secretase component and the sites of gamma-secretase activity, as defined by the production of Abeta. Finally, we close by synthesizing all of the included topics into an overarching model for the assembly and trafficking of the gamma-secretase complex, which serves as a launching point for further questions into the biology and function of gamma-secretase in Alzheimer's disease.

Shah S, Yu G. · Center for Basic Neuroscience and Department of Cell Biology, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA. · Mol Interv. · Pubmed #16565469 links to  free full text

Abstract: The accumulation of amyloid-beta peptides in the brain is a major factor of Alzheimer Disease. Central to the production of the amyloid-beta peptides are the proteolytic secretases, which, recently, have been important targets of drug discovery. Newly published results indicate that the sorting protein-related receptor sorLA/LR11 regulates processing and trafficking of the precursor of the amyloid-beta peptides, revealing an alternative target for developing molecular clinical therapeutic compounds for Alzheimer Disease.

Fraser PE, Yang DS, Yu G, Lévesque L, Nishimura M, Arawaka S, Serpell LC, Rogaeva E, St George-Hyslop P. · Centre for Research in Neurodegenerative Diseases, University of Toronto, Ont, Canada. · Biochim Biophys Acta. · Pubmed #10899427 No free full text.

Abstract: Numerous missense mutations in the presenilins are associated with the autosomal dominant form of familial Alzheimer disease. Presenilin genes encode polytopic transmembrane proteins, which are processed by proteolytic cleavage and form high-molecular-weight complexes under physiological conditions. The presenilins have been suggested to be functionally involved in developmental morphogenesis, unfolded protein responses and processing of selected proteins including the beta-amyloid precursor protein. Although the underlying mechanism by which presenilin mutations lead to development of Alzheimer disease remains elusive, one consistent mutational effect is an overproduction of long-tailed amyloid beta-peptides. Furthermore, presenilins interact with beta-catenin to form presenilin complexes, and the physiological and mutational effects are also observed in the catenin signal transduction pathway.

Nishimura M, Yu G, St George-Hyslop PH. · Centre for Research in Neurodegenerative Diseases, Department of Medicine, University of Toronto, Ontario, Canada. · Clin Genet. · Pubmed #10361981 No free full text.

Abstract: Many missense mutations in the presenilins are associated with autosomal dominant forms of familial Alzheimer disease (AD). Presenilin genes encode polytopic transmembrane proteins, which are processed by proteolytic cleavage and form high-molecular-weight complexes under physiological conditions. The presenilins have been suggested to be functionally involved in developmental morphogenesis, apoptosis signal pathways, and processing of selected proteins including beta-amyloid precursor protein. Although the underlying mechanism in which presenilin mutations lead to development of AD remains elusive, one consistent mutational effect is an overproduction of long-tailed amyloid beta-peptides. Furthermore, presenilins interact with beta-catenin to form presenilin complexes and presenilin mutations effect beta-catenin signalling pathways.

Mueller-Steiner S, Zhou Y, Arai H, Roberson ED, Sun B, Chen J, Wang X, Yu G, Esposito L, Mucke L, Gan L. · Gladstone Institute of Neurological Disease, University of California, San Francisco, 1650 Owens Street, 94158, USA. · Neuron. · Pubmed #16982417 No free full text.

Abstract: Alzheimer's disease (AD) may result from the accumulation of amyloid-beta (Abeta) peptides in the brain. The cysteine protease cathepsin B (CatB) is associated with amyloid plaques in AD brains and has been suspected to increase Abeta production. Here, we demonstrate that CatB actually reduces levels of Abeta peptides, especially the aggregation-prone species Abeta1-42, through proteolytic cleavage. Genetic inactivation of CatB in mice with neuronal expression of familial AD-mutant human amyloid precursor protein (hAPP) increased the relative abundance of Abeta1-42, worsening plaque deposition and other AD-related pathologies. Lentivirus-mediated expression of CatB in aged hAPP mice reduced preexisting amyloid deposits, even thioflavin S-positive plaques. Under cell-free conditions, CatB effectively cleaved Abeta1-42, generating C-terminally truncated Abeta peptides that are less amyloidogenic. Thus, CatB likely fulfills antiamyloidogenic and neuroprotective functions. Insufficient CatB activity might promote AD; increasing CatB activity could counteract the neuropathology of this disease.

Tu H, Nelson O, Bezprozvanny A, Wang Z, Lee SF, Hao YH, Serneels L, De Strooper B, Yu G, Bezprozvanny I. · Department of Physiology, UT Southwestern Medical Center at Dallas, Dallas, TX 75390, USA. · Cell. · Pubmed #16959576 No free full text.

Abstract: Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative disorder. Mutations in presenilins 1 and 2 (PS1 and PS2) account for approximately 40% of familial AD (FAD) cases. FAD mutations and genetic deletions of presenilins have been associated with calcium (Ca(2+)) signaling abnormalities. We demonstrate that wild-type presenilins, but not PS1-M146V and PS2-N141I FAD mutants, can form low-conductance divalent-cation-permeable ion channels in planar lipid bilayers. In experiments with PS1/2 double knockout (DKO) mouse embryonic fibroblasts (MEFs), we find that presenilins account for approximately 80% of passive Ca(2+) leak from the endoplasmic reticulum. Deficient Ca(2+) signaling in DKO MEFs can be rescued by expression of wild-type PS1 or PS2 but not by expression of PS1-M146V or PS2-N141I mutants. The ER Ca(2+) leak function of presenilins is independent of their gamma-secretase activity. Our data suggest a Ca(2+) signaling function for presenilins and provide support for the "Ca(2+) hypothesis of AD."

Pardossi-Piquard R, Dunys J, Yu G, St George-Hyslop P, Alves da Costa C, Checler F. · Institut de Pharmacologie Moléculaire et Cellulaire du Centre National de la Recherche Scientifique, Equipe labellisée Fondation pour la Recherche Médicale, Valbonne, France. · J Neurochem. · Pubmed #16606360 No free full text.

Abstract: We recently demonstrated that the presenilin-dependent gamma-secretase complex regulates the expression and activity of neprilysin, one of the main enzymes that degrade the amyloid beta-peptide (Abeta) which accumulates in Alzheimer's disease. Here, we examined the influence of endogenous nicastrin (NCT), a member of the gamma-secretase complex, on neprilysin physiology. We show that nicastrin deficiency drastically lowers neprilysin expression, membrane-bound activity and mRNA levels, but it did not modulate the expression of two other putative Abeta-cleaving enzymes, endothelin-converting enzyme and insulin-degrading enzyme. Furthermore, we show that nicastrin restores neprilysin activity and expression in nicastrin-deficient, but not presenilin-deficient fibroblasts, indicating that the control of neprilysin necessitates the complete gamma-secretase complex harbouring its four reported components. Finally, we show that NCT expression peaked 24 h after NCT cDNA transfection of wild-type and NCT-/- fibroblasts, while neprilysin expression drastically increased only after 36 h and was maximal at 48 h. This delayed effect on neprilysin expression correlates well with our demonstration of an indirect gamma-secretase-dependent modulation of neprilysin at its transcriptional level.

Garzon D, Yu G, Fahnestock M. · Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada. · J Neurochem. · Pubmed #12358753 No free full text.

Abstract: Brain-derived neurotrophic factor (BDNF) supports hippocampal, cortical and basal forebrain cholinergic neurons, which lose function in Alzheimer's disease. In Alzheimer's tissues such as hippocampus and parietal cortex, brain- derived neurotrophic factor mRNA is decreased three- to four-fold compared with controls. However, the molecular mechanism of the down-regulation of BDNF in Alzheimer's disease is unknown. The human brain-derived neurotrophic factor gene has multiple promoters governing six non-coding upstream exons that are spliced to one downstream coding exon, leading to six different transcripts. Here we report an alternate human splice variant within exon 4I for a total of seven transcripts. Previous brain-derived neurotrophic factor mRNA measurements in Alzheimer's disease tissue were done using the downstream coding exon present in all transcripts. Using RT-PCR primers specific for each upstream exon, we observe a significant decrease in three human brain-derived neurotrophic factor mRNA transcripts in Alzheimer's disease samples compared with controls. Transcripts 1 and 3 each exhibit a two-fold decrease, and transcript 2 shows a five-fold decrease. There are no significant differences between control and Alzheimer's disease samples for the other transcripts, including the new splice variant. In rat, both transcripts 1 and 3 are regulated through the transcription factor cAMP response element binding protein, whose phosphorylation is decreased in the Alzheimer's disease brain. This could lead to specific down-regulation of the brain-derived neurotrophic factor transcripts shown here.

Yang DS, Tandon A, Chen F, Yu G, Yu H, Arawaka S, Hasegawa H, Duthie M, Schmidt SD, Ramabhadran TV, Nixon RA, Mathews PM, Gandy SE, Mount HT, St George-Hyslop P, Fraser PE. · Centre for Research in Neurodegenerative Diseases, Tanz Neuroscience Building, University of Toronto, Toronto, Ontario M5S 3H2, Canada. · J Biol Chem. · Pubmed #12032140 links to  free full text

Abstract: Nicastrin is an integral component of the high molecular weight presenilin complexes that control proteolytic processing of the amyloid precursor protein and Notch. We report here that nicastrin is most probably a type 1 transmembrane glycoprotein that is expressed at moderate levels in the brain and in cultured neurons. Immunofluorescence studies demonstrate that nicastrin is localized in the endoplasmic reticulum, Golgi, and a discrete population of vesicles. Glycosidase analyses reveal that endogenous nicastrin undergoes a conventional, trafficking-dependent maturation process. However, when highly expressed in transfected cells, there is a disproportionate accumulation of the endo-beta-N-acetylglucosaminidase H-sensitive, immature form, with no significant increase in the levels of the fully mature species. Immunoprecipitation revealed that presenilin-1 interacts preferentially with mature nicastrin, suggesting that correct trafficking and co-localization of the presenilin complex components are essential for activity. These findings demonstrate that trafficking and post-translational modifications of nicastrin are tightly regulated processes that accompany the assembly of the active presenilin complexes that execute gamma-secretase cleavage. These results also underscore the caveat that simple overexpression of nicastrin in transfected cells may result in the accumulation of large amounts of the immature protein, which is apparently unable to assemble into the active complexes capable of processing amyloid precursor protein and Notch.

Fergani A, Yu G, St George-Hyslop P, Checler F. · IPMC du CNRS, UMR6097, 660 route des Lucioles, 06560 Valbonne, France. · Biochem Biophys Res Commun. · Pubmed #11726200 No free full text.

Abstract: Nicastrin is a recently discovered protein interacting with presenilins and the beta-amyloid precursor protein, the proteins playing key roles in Alzheimer's disease and which, when mutated, appear responsible for early-onset familial forms of Alzheimer's disease. Nicastrin was reported to modulate beta-amyloid production, a phenotype affected differently by missense mutations or deletions of a conserved hydrophilic domain. In addition to such a function, nicastrin was recently suggested to possess putative catalytic activity based on its sequence homology with enzymes of the aminopeptidase family. We set up stably transfected human HEK293 cells expressing either wild-type or mutated nicastrins and we show that these proteins do not exhibit aminopeptidase M- and B-like activities.

Chen F, Yu G, Arawaka S, Nishimura M, Kawarai T, Yu H, Tandon A, Supala A, Song YQ, Rogaeva E, Milman P, Sato C, Yu C, Janus C, Lee J, Song L, Zhang L, Fraser PE, St George-Hyslop PH. · Centre for Research in Neurodegenerative Diseases; Departments of Medicine and Medical Biophysics, University of Toronto, Tanz Neuroscience Building, 6 Queen's Park Crescent West, Toronto, Ontario M5S 3H2, Canada. · Nat Cell Biol. · Pubmed #11483961 No free full text.

Abstract: The presenilins and nicastrin, a type 1 transmembrane glycoprotein, form high molecular weight complexes that are involved in cleaving the beta-amyloid precursor protein (betaAPP) and Notch in their transmembrane domains. The former process (termed gamma-secretase cleavage) generates amyloid beta-peptide (Abeta), which is involved in the pathogenesis of Alzheimer's disease. The latter process (termed S3-site cleavage) generates Notch intracellular domain (NICD), which is involved in intercellular signalling. Nicastrin binds both full-length betaAPP and the substrates of gamma-secretase (C99- and C83-betaAPP fragments), and modulates the activity of gamma-secretase. Although absence of the Caenorhabditis elegans nicastrin homologue (aph-2) is known to cause an embryonic-lethal glp-1 phenotype, the role of nicastrin in this process has not been explored. Here we report that nicastrin binds to membrane-tethered forms of Notch (substrates for S3-site cleavage of Notch), and that, although mutations in the conserved 312-369 domain of nicastrin strongly modulate gamma-secretase, they only weakly modulate the S3-site cleavage of Notch. Thus, nicastrin has a similar role in processing Notch and betaAPP, but the 312-369 domain may have differential effects on these activities. In addition, we report that the Notch and betaAPP pathways do not significantly compete with each other.

Fraser PE, Yu G, Lévesque L, Nishimura M, Yang DS, Mount HT, Westaway D, St George-Hyslop PH. · Department of Medicine, University of Toronto, Toronto, Ontario M5S 3H2, Canada. · Biochem Soc Symp. · Pubmed #11447843 No free full text.

Abstract: Missense mutations in presenilin 1 (PS1) and presenilin 2 (PS2) are associated with early-onset familial Alzheimer's disease which displays an accelerated deposition of amyloid plaques and neurofibrillary tangles. Presenilins are multi-spanning transmembrane proteins which localize primarily to the endoplasmic reticulum and the Golgi compartments. We have previously demonstrated that PS1 exists as a high-molecular-mass complex that is likely to contain several functional ligands. Potential binding proteins were screened by the yeast two-hybrid system using the cytoplasmically orientated PS1 loop domain which was shown to interact strongly with members of the armadillo family of proteins, including beta-catenin, p0071 and a novel neuron-specific plakophilin-related armadillo protein (NPRAP). Armadillo proteins can have dual functions that encompass the stabilization of cellular junctions/synapses and the mediation of signal transduction pathways. Our observations suggest that PS1 may contribute to both aspects of armadillo-related pathways involving neurite outgrowth and nuclear translocation of beta-catenin upon activation of the wingless (Wnt) pathway. Alzheimer's disease (AD)-related presenilin mutations exhibit a dominant gain of aberrant function resulting in the prevention of beta-catenin translocation following Wnt signalling. These findings indicate a functional role for PS1 in signalling and suggest that mistrafficking of selected presenilin ligands may be a potential mechanism in the genesis of AD.

Yu G, Chen F, Nishimura M, Steiner H, Tandon A, Kawarai T, Arawaka S, Supala A, Song YQ, Rogaeva E, Holmes E, Zhang DM, Milman P, Fraser P, Haass C, St George-Hyslop P. · Centre for Research in Neurodegenerative Diseases, Department of Medical, Biophysics, University of Toronto, Ontario, Canada. · Acta Neurol Scand Suppl. · Pubmed #11261807 No free full text.

Abstract: Presenilin (PS1 and PS2) holoproteins are transiently incorporated into low molecular weight (MW) complexes. During subsequent incorporation into a higher MW complex, they undergo endoproteolysis to generate stable N- and C-terminal fragments (NTF/CTF). Mutation of either of two conserved aspartate residues in transmembrane domains inhibits both presenilin-endoproteolysis and the proteolytic processing of APP and Notch. We show that aspartate-mutant holoprotein presenilins are not incorporated into the high molecular weight, NTF/CTF-containing complexes. Aspartate-mutant presenilin holoproteins also preclude entry of endogenous wild-type PS1/PS2 into the high molecular weight complexes, but do not affect the incorporation of wild-type holoproteins into lower molecular weight holoprotein complexes. These data suggest that the loss-of-function aspartate-mutants cause altered PS complex maturation, and argue that the functional presenilin moieties are contained in the high molecular weight presenilin NTF/CTF-containing complexes.

Van Gassen G, De Jonghe C, Nishimura M, Yu G, Kuhn S, St George-Hyslop P, Van Broeckhoven C. · Molecular Genetics Laboratory, Neurogenetics Group, Flanders Interuniversity Institute for Biotechnology (VIB), Born-Bunge Foundation, University of Antwerp, Belgium. · Mol Med. · Pubmed #10997338 links to  free full text

Abstract: BACKGROUND: Mutations in the presenilin (PSEN) genes are responsible for the majority of early-onset Alzheimer disease (AD) cases. PSEN1 is a component of a high molecular weight, endoplasmic reticulum, membrane-bound protein complex, including beta-catenin. Pathogenic PSEN1 mutations were demonstrated to have an effect on beta-catenin and glycogen synthase kinase-3beta(GSK-3beta), two members of the wingless Wnt pathway. The nuclear translocation and the stability of beta-catenin, and the interaction between GSK3beta and PSEN1 were influenced. MATERIALS AND METHODS: Stably transfected human embryonic kidney (HEK) 293 cells overexpressing wild-type (wt) and mutant (mt) PSEN1, treated with and without LiCl, were used to isolate cytoplasmic and nuclear fractions. By Western blot analysis, endogenous beta-catenin levels were examined. By analyzing cytosolic fractions of PSEN1, transfected and nontransfected HEK 293 cells, and total brain extracts of AD patients and controls, we evaluated the effect of PSEN1 overexpression on beta-catenin stability. Finally, we analyzed the effect of pathogenic PSEN1 mutations on the interaction between PSEN1 and GSK3beta by co-immunoprecipitation experiments. RESULTS: We report reduced nuclear translocation of beta-catenin in cells stably expressing I143T, G384A, and T113-114ins PSEN1. The G384A PSEN1 mutation showed a similar pronounced effect on nuclear translocation of beta-catenin, as reported for processing of amyloid precursor protein (APP) into amyloid beta(Abeta). Overexpression of PSEN1 and the presence of pathogenic mutations in PSEN1 had no significant effect on the stability of beta-catenin. Nonspecific binding of overexpressed PSEN1 to endogenous GSK3beta was observed when GSK3beta was immunoprecipitated. Immunoprecipitation of PSEN1 in cells overexpressing PSEN1 and in native cells, however, did not result in co-immunoprecipitation of endogenous GSK3beta. CONCLUSION: Our results further establish the nuclear translocation assay of beta-catenin as an adequate alternative for traditional Abeta measurement to evaluate the effect of PSEN1 mutations on biochemical processes. We detected no significant effect of overexpressed wt or mt PSEN1 on the stability of beta-catenin. Finally, co-immunoprecipitation between PSEN1 and GSK3beta was not observed in our experimental setup.

Chen F, Yang DS, Petanceska S, Yang A, Tandon A, Yu G, Rozmahel R, Ghiso J, Nishimura M, Zhang DM, Kawarai T, Levesque G, Mills J, Levesque L, Song YQ, Rogaeva E, Westaway D, Mount H, Gandy S, St George-Hyslop P, Fraser PE. · Centre for Research in Neurodegenerative Diseases, Departments of Laboratory Medicine and Pathobiology, Medical Biophysics and Medicine, University of Toronto, Ontario, Canada. · J Biol Chem. · Pubmed #10962005 links to  free full text

Abstract: Absence of functional presenilin 1 (PS1) protein leads to loss of gamma-secretase cleavage of the amyloid precursor protein (betaAPP), resulting in a dramatic reduction in amyloid beta peptide (Abeta) production and accumulation of alpha- or beta-secretase-cleaved COOH-terminal fragments of betaAPP (alpha- or beta-CTFs). The major COOH-terminal fragment (CTF) in brain was identified as betaAPP-CTF-(11-98), which is consistent with the observation that cultured neurons generate primarily Abeta-(11-40). In PS1(-/-) murine neurons and fibroblasts expressing the loss-of-function PS1(D385A) mutant, CTFs accumulated in the endoplasmic reticulum, Golgi, and lysosomes, but not late endosomes. There were some subtle differences in the subcellular distribution of CTFs in PS1(-/-) neurons as compared with PS1(D385A) mutant fibroblasts. However, there was no obvious redistribution of full-length betaAPP or of markers of other organelles in either mutant. Blockade of endoplasmic reticulum-to-Golgi trafficking indicated that in PS1(-/-) neurons (as in normal cells) trafficking of betaAPP to the Golgi compartment is necessary before alpha- and beta-secretase cleavages occur. Thus, although we cannot exclude a specific role for PS1 in trafficking of CTFs, these data argue against a major role in general protein trafficking. These results are more compatible with a role for PS1 either as the actual gamma-secretase catalytic activity or in other functions indirectly related to gamma-secretase catalysis (e.g. an activator of gamma-secretase, a substrate adaptor for gamma-secretase, or delivery of gamma-secretase to betaAPP-containing compartments).

Smith SK, Anderson HA, Yu G, Robertson AG, Allen SJ, Tyler SJ, Naylor RL, Mason G, Wilcock GW, Roche PA, Fraser PE, Dawbarn D. · Molecular Neurobiology Unit, Department of Medicine (Care of the Elderly), University of Bristol, Bristol, BS2 8HW, UK. · Brain Res Mol Brain Res. · Pubmed #10891589 No free full text.

Abstract: Mutations in the presenilin 1 gene have been shown to result in Alzheimer's disease. Presenilin 1 is a multi-transmembrane protein with a large hydrophilic loop near the C-terminus. This region is required for known functions of presenilin 1. We have constrained this loop within the active site of the bacterial protein, thioredoxin, to mimic its native conformational state. This hybrid protein was used as bait in a yeast two hybrid screen in an attempt to identify presenilin binding proteins. By this method syntaxin 1A, a synaptic plasma membrane protein, was identified as a novel binding protein for presenilin 1. In vitro experiments confirm the two-hybrid results suggesting that PS1 binds syntaxin under physiological conditions.

Levesque G, Yu G, Nishimura M, Zhang DM, Levesque L, Yu H, Xu D, Liang Y, Rogaeva E, Ikeda M, Duthie M, Murgolo N, Wang L, VanderVere P, Bayne ML, Strader CD, Rommens JM, Fraser PE, St George-Hyslop P. · Centre for Research in Neurodegenerative Diseases, Department of Medicine (Neurology), University of Toronto, and Toronto Hospital, Ontario, Canada. · J Neurochem. · Pubmed #10037471 No free full text.

Abstract: Missense substitutions in the presenilin 1 (PS1) and presenilin 2 (PS2) proteins are associated with early-onset familial Alzheimer's disease. We have used yeast-two-hybrid and coimmunoprecipitation methods to show that the large cytoplasmic loop domains of PS1 and PS2 interact specifically with three members of the armadillo protein family, including beta-catenin, p0071, and a novel neuronal-specific armadillo protein--neural plakophilin-related armadillo protein (NPRAP). The PS1:NPRAP interaction occurs between the arm repeats of NPRAP and residues 372-399 at the C-terminal end of the large cytoplasmic loop of PS1. The latter residues contain a single arm-like domain and are highly conserved in the presenilins, suggesting that they form a functional armadillo protein binding site for the presenilins.

Nishimura M, Yu G, Levesque G, Zhang DM, Ruel L, Chen F, Milman P, Holmes E, Liang Y, Kawarai T, Jo E, Supala A, Rogaeva E, Xu DM, Janus C, Levesque L, Bi Q, Duthie M, Rozmahel R, Mattila K, Lannfelt L, Westaway D, Mount HT, Woodgett J, St George-Hyslop P. · Centre for Research in Neurodegenerative Diseases, Department of Medicine (Neurology), University of Toronto, Ontario, Canada. · Nat Med. · Pubmed #9930863 No free full text.

Abstract: The presenilin proteins are components of high-molecular-weight protein complexes in the endoplasmic reticulum and Golgi apparatus that also contain beta-catenin. We report here that presenilin mutations associated with familial Alzheimer disease (but not the non-pathogenic Glu318Gly polymorphism) alter the intracellular trafficking of beta-catenin after activation of the Wnt/beta-catenin signal transduction pathway. As with their effect on betaAPP processing, the effect of PS1 mutations on trafficking of beta-catenin arises from a dominant 'gain of aberrant function' activity. These results indicate that mistrafficking of selected presenilin ligands is a candidate mechanism for the genesis of Alzheimer disease associated with presenilin mutations, and that dysfunction in the presenilin-beta-catenin protein complexes is central to this process.

Rogaeva EA, Premkumar S, Grubber J, Serneels L, Scott WK, Kawarai T, Song Y, Hill DL, Abou-Donia SM, Martin ER, Vance JJ, Yu G, Orlacchio A, Pei Y, Nishimura M, Supala A, Roberge B, Saunders AM, Roses AD, Schmechel D, Crane-Gatherum A, Sorbi S, Bruni A, Small GW, Conneally PM, Haines JL, Van Leuven F, St George-Hyslop PH, Farrer LA, Pericak-Vance MA. · No affiliation provided · Nat Genet. · Pubmed #10319855 No free full text.

This publication has no abstract.