11 results on '"Peter, St George-Hyslop"'
Search Results
2. p53-Dependent Aph-1 and Pen-2 anti-apoptotic phenotype requires the integrity of the gamma-secretase complex but is independent of its activity
- Author
-
Virginia Dolcini, Cristine Alves da Costa, Jean Sevalle, Julie Dunys, Frédéric Checler, Peter St George-Hyslop, T. Kawarai, Institut de pharmacologie moléculaire et cellulaire (IPMC), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), Centre for Research in Neurodegenerative Diseases, University of Toronto, and CNRS, APOPIS, FRM, URMA
- Subjects
MESH: Membrane Glycoproteins ,Apoptosis ,MESH: Amyloid beta-Protein ,Biochemistry ,0302 clinical medicine ,MESH: Caspase 3 ,Amyloid precursor protein ,Staurosporine ,APH-1 ,Enzyme Inhibitors ,MESH: Tumor Suppressor Protein p53 ,0303 health sciences ,Membrane Glycoproteins ,biology ,Caspase 3 ,Presenilins ,MESH: Presenilins ,Cell biology ,Phenotype ,MESH: Enzyme Inhibitors ,[SDV.NEU]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC] ,MESH: Membrane Proteins ,Poly(ADP-ribose) Polymerases ,medicine.drug ,Programmed cell death ,Nicastrin ,MESH: Phenotype ,Presenilin ,Cell Line ,03 medical and health sciences ,PEN-2 ,Endopeptidases ,medicine ,Humans ,Molecular Biology ,030304 developmental biology ,MESH: Humans ,Amyloid beta-Peptides ,MESH: Apoptosis ,MESH: Poly(ADP-ribose) Polymerases ,Membrane Proteins ,Cell Biology ,MESH: Multiprotein Complexes ,MESH: Cell Line ,MESH: Amyloid Precursor Protein Secretases ,Multiprotein Complexes ,MESH: Staurosporine ,biology.protein ,Amyloid Precursor Protein Secretases ,Tumor Suppressor Protein p53 ,030217 neurology & neurosurgery ,Peptide Hydrolases - Abstract
The presenilin-dependent gamma-secretase activity, which is responsible for the generation of amyloid beta-peptide, is a high molecular weight complex composed of at least four components, namely, presenilin-1 (or presenilin-2), nicastrin, Aph-1, and Pen-2. Previous data indicated that presenilins, which are thought to harbor the catalytic core of the complex, also control p53-dependent cell death. Whether the other components of the gamma-secretase complex could also modulate the cell death process in mammalian neurons remained to be established. Here, we examined the putative contribution of Aph-1 and Pen-2 in the control of apoptosis in TSM1 cells from a neuronal origin. We show by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling and DNA fragmentation analyses that the overexpression of Aph-1a, Aph-1b, or Pen-2 drastically lowered staurosporine-induced cellular toxicity. In support of an apoptosis rather than necrosis process, Aph-1 and Pen-2 also lower staurosporine- and etoposide-induced caspase-3 expression and diminished caspase-3 activity and poly(ADP-ribose) polymerase inactivation. The Aph-1 and Pen-2 anti-apoptotic phenotype was associated with a drastic reduction of p53 expression and activity and lowered p53 mRNA transcription. Furthermore, the Aph-1- and Pen-2-associated reduction of staurosporine-induced caspase-3 activation was fully abolished by p53 deficiency. Conversely, Aph-1a, Aph-1b, and Pen-2 gene inactivation increases both caspase-3 activity and p53 mRNA levels. Finally, we show that Aph-1 and Pen-2 did not trigger an anti-apoptotic response in cells devoid of presenilins or nicastrin, whereas the protective response was still observed in fibroblasts devoid of beta-amyloid precursor protein and amyloid precursor protein like-protein 2. Furthermore, Aph-1- and Pen-2-associated protection against staurosporine-induced caspase-3 activation was not affected by the gamma-secretase inhibitors N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester and difluoromethylketone. Altogether, our study indicates that Aph-1 and Pen-2 trigger an anti-apoptotic response by lowering p53-dependent control of caspase-3. Our work also demonstrates that this phenotype is strictly dependent on the molecular integrity of the gamma-secretase complex but remains independent of the gamma-secretase catalytic activity.
- Published
- 2007
3. Cytosolic proteins regulate alpha-synuclein dissociation from presynaptic membranes
- Author
-
Peter St George-Hyslop, Sabine Wislet-Gendebien, Anurag Tandon, Toshitaka Kawarai, Cheryl A. D'Souza, Paul E. Fraser, and David Westaway
- Subjects
animal diseases ,Synaptic Membranes ,Mice, Transgenic ,Biology ,Biochemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Mice ,0302 clinical medicine ,Cytosol ,Downregulation and upregulation ,mental disorders ,Animals ,Withdrawals/Retractions ,Molecular Biology ,030304 developmental biology ,Regulation of gene expression ,Alpha-synuclein ,Brain Chemistry ,0303 health sciences ,Vesicle ,Temperature ,Proteins ,Parkinson Disease ,Cell Biology ,nervous system diseases ,Cell biology ,Up-Regulation ,Kinetics ,Membrane ,nervous system ,chemistry ,Gene Expression Regulation ,Cytoplasm ,alpha-Synuclein ,030217 neurology & neurosurgery ,Intracellular ,Synaptosomes - Abstract
Intracellular accumulation of insoluble alpha-synuclein in Lewy bodies is a key neuropathological trait of Parkinson disease (PD). Neither the normal function of alpha-synuclein nor the biochemical mechanisms that cause its deposition are understood, although both are likely influenced by the interaction of alpha-synuclein with vesicular membranes, either for a physiological role in vesicular trafficking or as a pathological seeding mechanism that exacerbates the propensity of alpha-synuclein to self-assemble into fibrils. In addition to the alpha-helical form that is peripherally-attached to vesicles, a substantial portion of alpha-synuclein is freely diffusible in the cytoplasm. The mechanisms controlling alpha-synuclein exchange between these compartments are unknown and the possibility that chronic dysregulation of membrane-bound and soluble alpha-synuclein pools may contribute to Lewy body pathology led us to search for cellular factors that can regulate alpha-synuclein membrane interactions. Here we reveal that dissociation of membrane-bound alpha-synuclein is dependent on brain-specific cytosolic proteins and insensitive to calcium or metabolic energy. Two PD-linked mutations (A30P and A53T) significantly increase the cytosol-dependent alpha-synuclein off-rate but have no effect on cytosol-independent dissociation. These results reveal a novel mechanism by which cytosolic brain proteins modulate alpha-synuclein interactions with intracellular membranes. Importantly, our finding that alpha-synuclein dissociation is up-regulated by both familial PD mutations implicates cytosolic cofactors in disease pathogenesis and as molecular targets to influence alpha-synuclein aggregation.
- Published
- 2006
4. Both the sequence and length of the C terminus of PEN-2 are critical for intermolecular interactions and function of presenilin complexes
- Author
-
Gerold Schmitt-Ulms, Peter St George-Hyslop, Taiichi Katayama, Cortney Shier, Agnes Petit, Nobuo Sanjo, Yongjun Gu, Paul M. Mathews, Hiroshi Hasegawa, Fusheng Chen, Toshitaka Kawarai, Paul E. Fraser, Stephen D. Schmidt, Institut de pharmacologie moléculaire et cellulaire (IPMC), Centre National de la Recherche Scientifique (CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)
- Subjects
DNA, Complementary ,Stereochemistry ,[SDV]Life Sciences [q-bio] ,Molecular Sequence Data ,Nicastrin ,Biochemistry ,Presenilin ,Cell Line ,03 medical and health sciences ,0302 clinical medicine ,Protein structure ,PEN-2 ,Centrifugation, Density Gradient ,Animals ,Humans ,Immunoprecipitation ,Amino Acid Sequence ,APH-1 ,Cycloheximide ,Molecular Biology ,Peptide sequence ,ComputingMilieux_MISCELLANEOUS ,030304 developmental biology ,Gene Library ,0303 health sciences ,Amyloid beta-Peptides ,biology ,Chemistry ,C-terminus ,Brain ,Membrane Proteins ,Cell Biology ,Transmembrane protein ,Protein Structure, Tertiary ,Mutation ,biology.protein ,Mutagenesis, Site-Directed ,RNA Interference ,Amyloid Precursor Protein Secretases ,030217 neurology & neurosurgery ,Gene Deletion ,Plasmids ,Protein Binding - Abstract
Presenilin 1 or presenilin 2, nicastrin, APH-1, and PEN-2 form high molecular weight complexes that play a pivotal role in the cleavage of various Type I transmembrane proteins, including the beta-amyloid precursor protein. The specific function of PEN-2 is unclear. To explore its function and intermolecular interactions, we conducted deletion and mutagenesis studies on a series of conserved residues at the C terminus of PEN-2. These studies suggest that: 1) both the presence and amino acid sequence of the conserved DYLSF domain at the C terminus of PEN-2 (residues 90-94) is critical for binding PEN-2 to other components in the presenilin complex and 2) the overall length of the exposed C terminus is critical for functional gamma-secretase activity.
- Published
- 2004
5. APH-1 interacts with mature and immature forms of presenilins and nicastrin and may play a role in maturation of presenilin.nicastrin complexes
- Author
-
Toshitaka Kawarai, Howard T.J. Mount, Peter St George-Hyslop, Anurag Tandon, Nobuo Sanjo, Anchla Luthra, Fusheng Chen, Monica Duthie, Paul E. Fraser, Yongjun Gu, Hiroshi Hasegawa, Wenping Li, and Xueying Ruan
- Subjects
DNA, Complementary ,Glycosylation ,Blotting, Western ,Molecular Sequence Data ,Nicastrin ,Golgi Apparatus ,Centrifugation ,Plasma protein binding ,Endoplasmic Reticulum ,Transfection ,Biochemistry ,Presenilin ,Catalysis ,Cell Line ,symbols.namesake ,PEN-2 ,Triiodobenzoic Acids ,Endopeptidases ,Presenilin-2 ,Presenilin-1 ,Humans ,Amino Acid Sequence ,APH-1 ,Molecular Biology ,Membrane Glycoproteins ,biology ,Sequence Homology, Amino Acid ,Endoplasmic reticulum ,Temperature ,Brain ,Membrane Proteins ,Cell Biology ,Golgi apparatus ,Immunohistochemistry ,Precipitin Tests ,Membrane protein ,symbols ,biology.protein ,Amyloid Precursor Protein Secretases ,Peptide Hydrolases ,Protein Binding - Abstract
APH-1 and PEN-2 genes modulate the function of nicastrin and the presenilins in Caenorhabditis elegans. Preliminary studies in transfected mammalian cells overexpressing tagged APH-1 proteins suggest that this genetic interaction is mediated by a direct physical interaction. Using the APH-1 protein encoded on human chromosome 1 (APH-1(1)L; also known as APH-1a) as an archetype, we report here that endogenous forms of APH-1 are predominantly expressed in intracellular membrane compartments, including the endoplasmic reticulum and cis-Golgi. APH-1 proteins directly interact with immature and mature forms of the presenilins and nicastrin within high molecular weight complexes that display gamma- and epsilon-secretase activity. Indeed APH-1 proteins can bind to the nicastrin delta312-369 loss of function mutant, which does not undergo glycosylation maturation and is not trafficking beyond the endoplasmic reticulum. The levels of expression of endogenous APH-1(1)L can be suppressed by overexpression of any other members of the APH-1 family, suggesting that their abundance is coordinately regulated. Finally, although the absence of APH-1 destabilizes the presenilins, in contrast to nicastrin and PEN-2, APH-1 itself is only modestly destabilized in cells lacking functional expression of presenilin 1 or presenilin 2. Taken together, our data suggest that APH-1 proteins, and APH-1(1) in particular, may have a role in the initial assembly and maturation of presenilin.nicastrin complexes.
- Published
- 2002
6. Presenilin 1 mutations activate gamma 42-secretase but reciprocally inhibit epsilon-secretase cleavage of amyloid precursor protein (APP) and S3-cleavage of notch
- Author
-
Paul E. Fraser, Fusheng Chen, Shigeki Arawaka, Peter St George-Hyslop, Hiroshi Hasegawa, David Westaway, Yongjun Gu, Xueying Ruan, and Howard T.J. Mount
- Subjects
Blotting, Western ,Molecular Sequence Data ,Cleavage (embryo) ,Transfection ,Biochemistry ,Presenilin ,Catalysis ,Mass Spectrometry ,Cell Line ,Amyloid beta-Protein Precursor ,Microsomes ,mental disorders ,Endopeptidases ,Amyloid precursor protein ,Presenilin-1 ,Aspartic Acid Endopeptidases ,Humans ,Amino Acid Sequence ,APH-1 ,Molecular Biology ,biology ,Models, Genetic ,Receptors, Notch ,C-terminus ,Temperature ,Membrane Proteins ,Cell Biology ,Precipitin Tests ,Cell biology ,Protein Structure, Tertiary ,Enzyme Activation ,Transmembrane domain ,Alpha secretase ,Mutation ,biology.protein ,Amyloid Precursor Protein Secretases ,Amyloid precursor protein secretase ,Protein Binding - Abstract
The presenilin 1 (PS1) and presenilin 2 (PS2) proteins are necessary for proteolytic cleavage of the amyloid precursor protein (APP) within its transmembrane domain. One of these cleavage events (termed gamma-secretase) generates the C-terminal end of the Abeta-peptide by proteolysis near residue 710 or 712 of APP(770). Another event (termed gamma-like or epsilon-secretase cleavage) cleaves near residue 721 at approximately 2-5 residues inside the cytoplasmic membrane boundary to generate a series of stable, C-terminal APP fragments. This latter cleavage is analogous to S3-cleavage of Notch. We report here that specific mutations in the N terminus, loop, or C terminus of PS1 all increase the production of Abeta(42) but cause inhibition of both epsilon-secretase cleavage of APP and S3-cleavage of Notch. These data support the hypothesis that epsilon-cleavage of APP and S3-cleavage of Notch are similar events. They also argue that, although both the gamma-site and the epsilon-site cleavage of APP are presenilin-dependent, they are likely to be independent catalytic events.
- Published
- 2002
7. Disturbed activation of endoplasmic reticulum stress transducers by familial Alzheimer's disease-linked presenilin-1 mutations
- Author
-
Masatoshi Takeda, Taiichi Katayama, Peter St George-Hyslop, Kazutoshi Mori, Kazunori Imaizumi, Paul E. Fraser, Masaya Tohyama, Takashi Kudo, Akiko Honda, Richard Rozmahel, and Takunari Yoneda
- Subjects
endocrine system ,Protein Folding ,Time Factors ,animal diseases ,Mutant ,Blotting, Western ,Down-Regulation ,Biology ,medicine.disease_cause ,Bioinformatics ,Endoplasmic Reticulum ,Transfection ,Biochemistry ,Presenilin ,Mice ,Alzheimer Disease ,Stress, Physiological ,Transduction, Genetic ,mental disorders ,medicine ,Presenilin-1 ,Tumor Cells, Cultured ,Animals ,Humans ,Molecular Biology ,Genes, Dominant ,Mice, Knockout ,Mutation ,Aspartic Acid ,ATF6 ,Endoplasmic reticulum ,Membrane Proteins ,Translation (biology) ,Cell Biology ,Fibroblasts ,nervous system diseases ,Cell biology ,nervous system ,Microscopy, Fluorescence ,Unfolded protein response ,Signal transduction ,Plasmids ,Protein Binding ,Signal Transduction - Abstract
Recent studies have shown independently that presenilin-1 (PS1) null mutants and familial Alzheimer's disease (FAD)-linked mutants should both down-regulate signaling of the unfolded protein response (UPR). However, it is difficult to accept that both mutants possess the same effects on the UPR. Furthermore, contrary to these observations, neither loss of PS1 and PS2 function nor expression of FAD-linked PS1 mutants were reported to have a discernable impact on the UPR. Therefore, re-examination and detailed analyses are needed to clarify the relationship between PS1 function and UPR signaling. Here, we report that PS1/PS2 null and dominant negative PS1 mutants, which are mutated at aspartate residue 257 or 385, did not affect signaling of the UPR. In contrast, FAD-linked PS1 mutants were confirmed to disturb UPR signaling by inhibiting activation of both Ire1alpha and ATF6, both of which are endoplasmic reticulum (ER) stress transducers in the UPR. Furthermore, PS1 mutants also disturbed activation of PERK (PKR-like ER kinase), which plays a crucial role in inhibiting translation during ER stress. Taken together, these observations suggested that PS1 mutations could affect signaling pathways controlled by each of the respective ER-stress transducers, possibly through a gain-of-function.
- Published
- 2001
8. Early-onset amyloid deposition and cognitive deficits in transgenic mice expressing a double mutant form of amyloid precursor protein 695
- Author
-
Céline Morissette, Patrick Horne, George A. Carlson, Sherry Turner, Christopher Janus, Noah Zuker, Peter St George-Hyslop, David Westaway, Jacqueline Pearson, Paul E. Fraser, Amie L. Phinney, Dun-Shen Yang, Gianluca Lozza, Francine Gervais, Janet French, Suzanne Kunicki, Robert Strome, Mariagrazia Grilli, Catherine Bergeron, M. Azhar Chishti, Julie Paquette, and James E. Loukides
- Subjects
Genetically modified mouse ,Male ,medicine.medical_specialty ,Aging ,Amyloid ,Transgene ,BACE1-AS ,Restriction Mapping ,Morris water navigation task ,Mice, Transgenic ,Biochemistry ,Presenilin ,Amyloid beta-Protein Precursor ,Mice ,Internal medicine ,Amyloid precursor protein ,medicine ,Animals ,Humans ,Maze Learning ,Promoter Regions, Genetic ,Molecular Biology ,Crosses, Genetic ,Mice, Inbred C3H ,biology ,Brain ,Cell Biology ,Amyloidosis ,Biochemistry of Alzheimer's disease ,Mice, Inbred C57BL ,Endocrinology ,Amino Acid Substitution ,biology.protein ,Mutagenesis, Site-Directed ,Female ,Cognition Disorders - Abstract
We have created early-onset transgenic (Tg) models by exploiting the synergistic effects of familial Alzheimer's disease mutations on amyloid beta-peptide (Abeta) biogenesis. TgCRND8 mice encode a double mutant form of amyloid precursor protein 695 (KM670/671NL+V717F) under the control of the PrP gene promoter. Thioflavine S-positive Abeta amyloid deposits are present at 3 months, with dense-cored plaques and neuritic pathology evident from 5 months of age. TgCRND8 mice exhibit 3,200-4,600 pmol of Abeta42 per g brain at age 6 months, with an excess of Abeta42 over Abeta40. High level production of the pathogenic Abeta42 form of Abeta peptide was associated with an early impairment in TgCRND8 mice in acquisition and learning reversal in the reference memory version of the Morris water maze, present by 3 months of age. Notably, learning impairment in young mice was offset by immunization against Abeta42 (Janus, C., Pearson, J., McLaurin, J., Mathews, P. M., Jiang, Y., Schmidt, S. D., Chishti, M. A., Horne, P., Heslin, D., French, J., Mount, H. T. J., Nixon, R. A., Mercken, M., Bergeron, C., Fraser, P. E., St. George-Hyslop, P., and Westaway, D. (2000) Nature 408, 979-982). Amyloid deposition in TgCRND8 mice was enhanced by the expression of presenilin 1 transgenes including familial Alzheimer's disease mutations; for mice also expressing a M146L+L286V presenilin 1 transgene, amyloid deposits were apparent by 1 month of age. The Tg mice described here suggest a potential to investigate aspects of Alzheimer's disease pathogenesis, prophylaxis, and therapy within short time frames.
- Published
- 2001
9. Carboxyl-terminal fragments of Alzheimer beta-amyloid precursor protein accumulate in restricted and unpredicted intracellular compartments in presenilin 1-deficient cells
- Author
-
D. M. Zhang, G. Levesque, David Westaway, Gang Yu, Anurag Tandon, Ekaterina Rogaeva, Peter St George-Hyslop, Toshitaka Kawarai, Lyne Levesque, Masaki Nishimura, Paul E. Fraser, Fusheng Chen, Howard T.J. Mount, Richard Rozmahel, S.E. Gandy, Dun-Sheng Yang, Suzana Petanceska, Austin J. Yang, Jorge Ghiso, Julia Mills, and You-Qiang Song
- Subjects
Endosome ,Mutant ,Biology ,Biochemistry ,Presenilin ,symbols.namesake ,Amyloid beta-Protein Precursor ,Mice ,Alzheimer Disease ,mental disorders ,Endopeptidases ,Amyloid precursor protein ,Presenilin-1 ,Animals ,Aspartic Acid Endopeptidases ,Molecular Biology ,Mice, Knockout ,Amyloid beta-Peptides ,Activator (genetics) ,Endoplasmic reticulum ,Brain ,Membrane Proteins ,Cell Biology ,Golgi apparatus ,Peptide Fragments ,Cell biology ,Cell Compartmentation ,Microscopy, Electron ,nervous system ,symbols ,biology.protein ,Electrophoresis, Polyacrylamide Gel ,Amyloid Precursor Protein Secretases ,Intracellular ,Biomarkers - 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).
- Published
- 2000
10. Mutation of conserved aspartates affects maturation of both aspartate mutant and endogenous presenilin 1 and presenilin 2 complexes
- Author
-
Gang Yu, Fusheng Chen, Masaki Nishimura, Harald Steiner, Anurag Tandon, Toshitaka Kawarai, Shigeki Arawaka, Agnes Supala, You-Qiang Song, Ekaterina Rogaeva, Erin Holmes, Dong Mei Zhang, Paul Milman, Paul E. Fraser, Christian Haass, and Peter St. George-Hyslop
- Subjects
Aspartic Acid ,Mutagenesis ,Presenilin-2 ,Presenilin-1 ,Humans ,Membrane Proteins ,Cell Biology ,Molecular Biology ,Biochemistry ,Protein Processing, Post-Translational ,Cell Line - 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. Mutation of either of two conserved aspartate residues in transmembrane domains inhibits both presenilin-endoproteolysis and the proteolytic processing of beta-amyloid precursor protein and Notch. We show that although PS1/PS2 endoproteolysis is not required for inclusion into the higher MW N- and C-terminal fragment-containing complex, aspartate mutant holoprotein presenilins are not incorporated into the high MW complexes. Aspartate mutant presenilin holoproteins also preclude entry of endogenous wild type PS1/PS2 into the high MW complexes but do not affect the incorporation of wild type holoproteins into lower MW holoprotein complexes. These data suggest that the loss of function effects of the aspartate mutants result in altered PS complex maturation and argue that the functional presenilin moieties are contained in the high molecular weight complexes.
- Published
- 2000
11. Phosphorylation, subcellular localization, and membrane orientation of the Alzheimer's disease-associated presenilins
- Author
-
Barbara Cordell, Katleen Craessaerts, Peter St George-Hyslop, Bart Contreras, Fred Van Leuven, Paul E. Fraser, Dieder Moechars, Lyne Levesque, Monique Beullens, Mathieu Bollen, and Bart De Strooper
- Subjects
Models, Molecular ,CHO Cells ,Transfection ,Biochemistry ,Presenilin ,Cell membrane ,symbols.namesake ,Alzheimer Disease ,Cricetinae ,mental disorders ,Presenilin-2 ,medicine ,Amyloid precursor protein ,Presenilin-1 ,Animals ,Phosphorylation ,Fluorescent Antibody Technique, Indirect ,Molecular Biology ,biology ,Endoplasmic reticulum ,Chinese hamster ovary cell ,Cell Membrane ,Membrane Proteins ,Cell Biology ,Golgi apparatus ,Subcellular localization ,Cell biology ,medicine.anatomical_structure ,Membrane protein ,COS Cells ,symbols ,biology.protein ,Protein Processing, Post-Translational ,Subcellular Fractions - Abstract
Presenilins 1 and 2 are unglycosylated proteins with apparent molecular mass of 45 and 50 kDa, respectively, in transfected COS-1 and Chinese hamster ovary cells. They colocalize with proteins from the endoplasmic reticulum and the Golgi apparatus in transfected and untransfected cells. In COS-1 cells low amounts of intact endogeneous presenilin 1 migrating at 45 kDa are detected together with relative larger amounts of presenilin 1 fragments migrating between 18 and 30 kDa. The presenilins have a strong tendency to form aggregates (mass of 100-250 kDa) in SDS-polyacrylamide gel electrophoresis, which can be partially resolved when denatured by SDS at 37 degrees C instead of 95 degrees C. Sulfation, glycosaminoglycan modification, or acylation of the presenilins was not observed, but both proteins are posttranslationally phosphorylated on serine residues. The mutations Ala-246 --> Glu or Cys-410 --> Tyr that cause Alzheimer's disease do not interfere with the biosynthesis or phosphorylation of presenilin 1. Finally, using low concentrations of digitonin to selectively permeabilize the cell membrane but not the endoplasmic reticulum membrane, it is demonstrated that the two major hydrophilic domains of presenilin 1 are oriented to the cytoplasm. The current investigation documents the posttranslational modifications and subcellular localization of the presenilins and indicates that postulated interactions with amyloid precursor protein metabolism should occur in the early compartments of the biosynthetic pathway.
- Published
- 1997
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.