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Shen T, Shi J, Zhao X, Fu L, Wang N, Zheng X, Chen Y, Li M, Ma C, Liu P, Zhu D. Presenilin 1 Is a Therapeutic Target in Pulmonary Hypertension and Promotes Vascular Remodeling. Am J Respir Cell Mol Biol 2024; 70:468-481. [PMID: 38381098 DOI: 10.1165/rcmb.2022-0426oc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 02/20/2024] [Indexed: 02/22/2024] Open
Abstract
Small muscular pulmonary artery remodeling is a dominant feature of pulmonary arterial hypertension (PAH). PSEN1 affects angiogenesis, cancer, and Alzheimer's disease. We aimed to determine the role of PSEN1 in the pathogenesis of vascular remodeling in pulmonary hypertension (PH). Hemodynamics and vascular remodeling in the Psen1-knockin and smooth muscle-specific Psen1-knockout mice were assessed. The functional partners of PSEN1 were predicted by bioinformatics analysis and biochemical experiments. The therapeutic effect of PH was evaluated by administration of the PSEN1-specific inhibitor ELN318463. We discovered that both the mRNA and protein levels of PSEN1 were increased over time in hypoxic rats, monocrotaline rats, and Su5416/hypoxia mice. Psen1 transgenic mice were highly susceptible to PH, whereas smooth muscle-specific Psen1-knockout mice were resistant to hypoxic PH. STRING analysis showed that Notch1/2/3, β-catenin, Cadherin-1, DNER (delta/notch-like epidermal growth factor-related receptor), TMP10, and ERBB4 appeared to be highly correlated with PSEN1. Immunoprecipitation confirmed that PSEN1 interacts with β-catenin and DNER, and these interactions were suppressed by the catalytic PSEN1 mutations D257A, D385A, and C410Y. PSEN1 was found to mediate the nuclear translocation of the Notch1 intracellular domains and activated RBP-Jκ. Octaarginine-coated liposome-mediated pharmacological inhibition of PSEN1 significantly prevented and reversed the pathological process in hypoxic and monocrotaline-induced PH. PSEN1 essentially drives the pathogenesis of PAH and interacted with the noncanonical Notch ligand DNER. PSEN1 can be used as a promising molecular target for treating PAH. PSEN1 inhibitor ELN318463 can prevent and reverse the progression of PH and can be developed as a potential anti-PAH drug.
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Affiliation(s)
- TingTing Shen
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - JiuCheng Shi
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - XiJuan Zhao
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - Li Fu
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - Na Wang
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - XiaoDong Zheng
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - YingLi Chen
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - MingHui Li
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - Cui Ma
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - PiXu Liu
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China
| | - DaLing Zhu
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
- College of Pharmacy, Harbin Medical University, Harbin, China
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2
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Do HN, Devkota S, Bhattarai A, Wolfe MS, Miao Y. Effects of presenilin-1 familial Alzheimer's disease mutations on γ-secretase activation for cleavage of amyloid precursor protein. Commun Biol 2023; 6:174. [PMID: 36788318 PMCID: PMC9929099 DOI: 10.1038/s42003-023-04539-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 01/30/2023] [Indexed: 02/16/2023] Open
Abstract
Presenilin-1 (PS1) is the catalytic subunit of γ-secretase which cleaves within the transmembrane domain of over 150 peptide substrates. Dominant missense mutations in PS1 cause early-onset familial Alzheimer's disease (FAD); however, the exact pathogenic mechanism remains unknown. Here we combined Gaussian accelerated molecular dynamics (GaMD) simulations and biochemical experiments to determine the effects of six representative PS1 FAD mutations (P117L, I143T, L166P, G384A, L435F, and L286V) on the enzyme-substrate interactions between γ-secretase and amyloid precursor protein (APP). Biochemical experiments showed that all six PS1 FAD mutations rendered γ-secretase less active for the endoproteolytic (ε) cleavage of APP. Distinct low-energy conformational states were identified from the free energy profiles of wildtype and PS1 FAD-mutant γ-secretase. The P117L and L286V FAD mutants could still sample the "Active" state for substrate cleavage, but with noticeably reduced conformational space compared with the wildtype. The other mutants hardly visited the "Active" state. The PS1 FAD mutants were found to reduce γ-secretase proteolytic activity by hindering APP residue L49 from proper orientation in the active site and/or disrupting the distance between the catalytic aspartates. Therefore, our findings provide mechanistic insights into how PS1 FAD mutations affect structural dynamics and enzyme-substrate interactions of γ-secretase and APP.
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Affiliation(s)
- Hung N. Do
- grid.266515.30000 0001 2106 0692Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66047 USA
| | - Sujan Devkota
- grid.266515.30000 0001 2106 0692Department of Medicinal Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS 66047 USA
| | - Apurba Bhattarai
- grid.266515.30000 0001 2106 0692Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66047 USA
| | - Michael S. Wolfe
- grid.266515.30000 0001 2106 0692Department of Medicinal Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS 66047 USA
| | - Yinglong Miao
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS, 66047, USA.
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3
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Genetics, Functions, and Clinical Impact of Presenilin-1 (PSEN1) Gene. Int J Mol Sci 2022; 23:ijms231810970. [PMID: 36142879 PMCID: PMC9504248 DOI: 10.3390/ijms231810970] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/09/2022] [Accepted: 09/14/2022] [Indexed: 12/29/2022] Open
Abstract
Presenilin-1 (PSEN1) has been verified as an important causative factor for early onset Alzheimer's disease (EOAD). PSEN1 is a part of γ-secretase, and in addition to amyloid precursor protein (APP) cleavage, it can also affect other processes, such as Notch signaling, β-cadherin processing, and calcium metabolism. Several motifs and residues have been identified in PSEN1, which may play a significant role in γ-secretase mechanisms, such as the WNF, GxGD, and PALP motifs. More than 300 mutations have been described in PSEN1; however, the clinical phenotypes related to these mutations may be diverse. In addition to classical EOAD, patients with PSEN1 mutations regularly present with atypical phenotypic symptoms, such as spasticity, seizures, and visual impairment. In vivo and in vitro studies were performed to verify the effect of PSEN1 mutations on EOAD. The pathogenic nature of PSEN1 mutations can be categorized according to the ACMG-AMP guidelines; however, some mutations could not be categorized because they were detected only in a single case, and their presence could not be confirmed in family members. Genetic modifiers, therefore, may play a critical role in the age of disease onset and clinical phenotypes of PSEN1 mutations. This review introduces the role of PSEN1 in γ-secretase, the clinical phenotypes related to its mutations, and possible significant residues of the protein.
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Banerjee R, Rudloff Z, Naylor C, Yu MC, Gunawardena S. The presenilin loop region is essential for glycogen synthase kinase 3 β (GSK3β) mediated functions on motor proteins during axonal transport. Hum Mol Genet 2019; 27:2986-3001. [PMID: 29790963 DOI: 10.1093/hmg/ddy190] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 05/10/2018] [Indexed: 01/05/2023] Open
Abstract
Neurons require intracellular transport of essential components for function and viability and defects in transport has been implicated in many neurodegenerative diseases including Alzheimer's disease (AD). One possible mechanism by which transport defects could occur is by improper regulation of molecular motors. Previous work showed that reduction of presenilin (PS) or glycogen synthase kinase 3 beta (GSK3β) stimulated amyloid precursor protein vesicle motility. Excess GSK3β caused transport defects and increased motor binding to membranes, while reduction of PS decreased active GSK3β and motor binding to membranes. Here, we report that functional PS and the catalytic loop region of PS is essential for the rescue of GSK3β-mediated axonal transport defects. Disruption of PS loop (PSΔE9) or expression of the non-functional PS variant, PSD447A, failed to rescue axonal blockages in vivo. Further, active GSK3β associated with and phosphorylated kinesin-1 in vitro. Our observations together with previous work that showed that the loop region of PS interacts with GSK3β propose a scaffolding mechanism for PS in which the loop region sequesters GSK3β away from motors for the proper regulation of motor function. These findings are important to uncouple the complex regulatory mechanisms that likely exist for motor activity during axonal transport in vivo.
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Affiliation(s)
- Rupkatha Banerjee
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - Zoe Rudloff
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - Crystal Naylor
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - Michael C Yu
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - Shermali Gunawardena
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY 14260, USA
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Kim HJ, Joe Y, Chen Y, Park GH, Kim UH, Chung HT. Carbon monoxide attenuates amyloidogenesis via down-regulation of NF-κB-mediated BACE1 gene expression. Aging Cell 2019; 18:e12864. [PMID: 30411846 PMCID: PMC6351829 DOI: 10.1111/acel.12864] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 09/03/2018] [Accepted: 09/15/2018] [Indexed: 12/18/2022] Open
Abstract
Amyloid-β (Aβ) peptides, the major constituent of plaques, are generated by sequential proteolytic cleavage of the amyloid precursor protein (APP) via β-secretase (BACE1) and the γ-secretase complex. It has been proposed that the abnormal secretion and accumulation of Aβ are the initial causative events in the development of Alzheimer's disease (AD). Drugs modulating this pathway could be used for AD treatment. Previous studies indicated that carbon monoxide (CO), a product of heme oxygenase (HO)-1, protects against Aβ-induced toxicity and promotes neuroprotection. However, the mechanism underlying the mitigative effect of CO on Aβ levels and BACE1 expression is unclear. Here, we show that CO modulates cleavage of APP and Aβ production by decreasing BACE1 expression in vivo and in vitro. CO reduces Aβ levels and improves memory deficits in AD transgenic mice. The regulation of BACE1 expression by CO is dependent on nuclear factor-kappa B (NF-κB). Consistent with the negative role of SIRT1 in the NF-κB activity, CO fails to evoke significant decrease in BACE1 expression in the presence of the SIRT1 inhibitor. Furthermore, CO attenuates elevation of BACE1 level in brains of 3xTg-AD mouse model as well as mice fed high-fat, high-cholesterol diets. CO reduces the NF-κB-mediated transcription of BACE1 induced by the cholesterol oxidation product 27-hydroxycholesterol or hydrogen peroxide. These data suggest that CO reduces the NF-κB-mediated BACE1 transcription and consequently decreases Aβ production. Our study provides novel mechanisms by which CO reduces BACE1 expression and Aβ production and may be an effective agent for AD treatment.
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Affiliation(s)
- Hyo Jeong Kim
- Meta-Inflammation Research Institute of Basic Research, School of Biological Sciences; University of Ulsan; Ulsan South Korea
| | - Yeonsoo Joe
- Meta-Inflammation Research Institute of Basic Research, School of Biological Sciences; University of Ulsan; Ulsan South Korea
| | - Yingqing Chen
- Meta-Inflammation Research Institute of Basic Research, School of Biological Sciences; University of Ulsan; Ulsan South Korea
| | - Gyu Hwan Park
- College of Pharmacy, Research Institute of Pharmaceutical Sciences; Kyungpook National University; Daegu South Korea
| | - Uh-Hyun Kim
- National Creative Research Laboratory for Ca Signaling Network, Medical School; Chonbuk National University; Jeonju South Korea
| | - Hun Taeg Chung
- Meta-Inflammation Research Institute of Basic Research, School of Biological Sciences; University of Ulsan; Ulsan South Korea
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Dong J, Qin W, Wei C, Tang Y, Wang Q, Jia J. A Novel PSEN1 K311R Mutation Discovered in Chinese Families with Late-Onset Alzheimer's Disease Affects Amyloid-β Production and Tau Phosphorylation. J Alzheimers Dis 2018; 57:613-623. [PMID: 28269784 DOI: 10.3233/jad-161188] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Presenilin-1 (PSEN1) is the most frequently mutated gene in familial Alzheimer's disease (AD), whereas only several novel mutations have been reported in China and functional studies were seldom conducted. OBJECTIVE We describe a novel PSEN1 K311R mutation in two Chinese families with late-onset AD and its functional impact on amyloid-β protein precursor (AβPP) processing and tau phosphorylation. METHODS The mutation was detected by direct sequencing of PSEN1 exon 9. HEK293 cells stably expressing wild-type APP695 (HEK293-APP695wt) were transfected with plasmids containing human wild-type PSEN1, PSEN1 K311R mutation, and PSEN1 E280A mutation to compare the K311R mutation's effects on AβPP processing with other groups. In addition, each group of cells were co-transfected with plasmids harboring PSEN1 and human wild-type MAPT complementary DNA to study the mutation's impacts on tau phosphorylation. RESULTS The K311R mutation was detected in probands of two late-onset AD families. Expression of the K311R or E280A mutation increased amyloid-β (Aβ)42 levels but decreased Aβ40 levels, resulting in an overall increase in the Aβ42/Aβ40 ratio compared to those in wild-type PSEN1 transfected cells (p < 0.05). The K311R or E280A mutation also increased the levels of phosphorylated tau compared to wild-type PSEN1 (p < 0.05). CONCLUSION The K311R mutation might contribute to AD pathogenesis by overproducing toxic Aβ species and enhancing tau phosphorylation. Further in-depth studies are needed to decipher the pathogenic mechanisms of the K311R mutation in terms of AβPP cleavage, tau phosphorylation, and other presenilin-1 mediated functional pathways.
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Affiliation(s)
- Jing Dong
- Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China
| | - Wei Qin
- Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China.,Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing, P.R. China.,Beijing Key Laboratory of Geriatric Cognitive Disorders, Beijing, P.R. China.,Key Neurodegenerative Laboratory of the Ministry of Education of the People's Republic of China, Beijing, P.R. China
| | - Cuibai Wei
- Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China.,Beijing Key Laboratory of Geriatric Cognitive Disorders, Beijing, P.R. China.,Key Neurodegenerative Laboratory of the Ministry of Education of the People's Republic of China, Beijing, P.R. China
| | - Yi Tang
- Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China
| | - Qi Wang
- Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China.,Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing, P.R. China.,Beijing Key Laboratory of Geriatric Cognitive Disorders, Beijing, P.R. China.,Key Neurodegenerative Laboratory of the Ministry of Education of the People's Republic of China, Beijing, P.R. China
| | - Jianping Jia
- Department of Neurology, Xuan Wu Hospital, Capital Medical University, Beijing, P.R. China.,Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing, P.R. China.,Beijing Key Laboratory of Geriatric Cognitive Disorders, Beijing, P.R. China.,Key Neurodegenerative Laboratory of the Ministry of Education of the People's Republic of China, Beijing, P.R. China
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7
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Park SY, Lee HR, Lee WS, Shin HK, Kim HY, Hong KW, Kim CD. Cilostazol Modulates Autophagic Degradation of β-Amyloid Peptide via SIRT1-Coupled LKB1/AMPKα Signaling in Neuronal Cells. PLoS One 2016; 11:e0160620. [PMID: 27494711 PMCID: PMC4975437 DOI: 10.1371/journal.pone.0160620] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 06/01/2016] [Indexed: 01/19/2023] Open
Abstract
A neuroprotective role of autophagy mediates the degradation of β-amyloid peptide (Aβ) in Alzheimer’s disease (AD). The previous study showed cilostazol modulates autophagy by increasing beclin1, Atg5 and LC3-II expressions, and depletes intracellular Aβ accumulation. This study elucidated the mechanisms through which cilostazol modulates the autophagic degradation of Aβ in neurons. In N2a cells, cilostazol (10–30 μM), significantly increased the expression of P-AMPKα (Thr 172) and downstream P-ACC (acetyl-CoA carboxylase) (Ser 79) as did resveratrol (SIRT1 activator), or AICAR (AMPK activator), which were blocked by KT5720, compound C (AMPK inhibitor), or sirtinol. Furthermore, phosphorylated-mTOR (Ser 2448) and phosphorylated-P70S6K (Thr 389) expressions were suppressed, and LC3-II levels were elevated in association with decreased P62/Sqstm1 by cilostazol. Cilostazol increased cathepsin B activity and decreased p62/SQSTM 1, consequently decreased accumulation of Aβ1–42 in the activated N2aSwe cells, and these results were blocked by sirtinol, compound C and bafilomycin A1 (autophagosome blocker), suggesting enhanced autophagosome formation by cilostazol. In SIRT1 gene-silenced N2a cells, cilostazol failed to increase the expressions of P-LKB1 (Ser 428) and P-AMPKα, which contrasted with its effect in negative control cells transfected with scrambled siRNA duplex. Further, N2a cells transfected with expression vectors encoding pcDNA SIRT1 showed increased P-AMPKα expression, which mimicked the effect of cilostazol in N2a cells; suggesting cilostazol-stimulated expressions of P-LKB1 and P-AMPKα were SIRT1-dependent. Unlike their effects in N2a cells, in HeLa cells, which lack LKB1, cilostazol and resveratrol did not elevate SIRT1 or P-AMPKα expression, indicating cilostazol and resveratrol-stimulated expressions of SIRT1 and P-AMPKα are LKB1-dependent. In conclusion, cilostazol upregulates autophagy by activating SIRT1-coupled P-LKB1/P-AMPKα and inhibiting mTOR activation, thereby decreasing Aβ accumulation.
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Affiliation(s)
- So Youn Park
- Department of Pharmacology, School of Korean Medicine, Pusan National University, Gyeongsangnam-do, 50612, Republic of Korea.,Gene & Cell Therapy Research Center for Vessel-associated Diseases, Pusan National University, Gyeongsangnam-do, 50612, Republic of Korea
| | - Hye Rin Lee
- Gene & Cell Therapy Research Center for Vessel-associated Diseases, Pusan National University, Gyeongsangnam-do, 50612, Republic of Korea
| | - Won Suk Lee
- Department of Pharmacology, School of Korean Medicine, Pusan National University, Gyeongsangnam-do, 50612, Republic of Korea
| | - Hwa Kyoung Shin
- Division of Meridian and Structural Medicine, Pusan National University, Gyeongsangnam-do, 50612, Republic of Korea
| | - Hye Young Kim
- Gene & Cell Therapy Research Center for Vessel-associated Diseases, Pusan National University, Gyeongsangnam-do, 50612, Republic of Korea
| | - Ki Whan Hong
- Gene & Cell Therapy Research Center for Vessel-associated Diseases, Pusan National University, Gyeongsangnam-do, 50612, Republic of Korea
| | - Chi Dae Kim
- Department of Pharmacology, School of Korean Medicine, Pusan National University, Gyeongsangnam-do, 50612, Republic of Korea.,Gene & Cell Therapy Research Center for Vessel-associated Diseases, Pusan National University, Gyeongsangnam-do, 50612, Republic of Korea
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8
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Lee HR, Shin HK, Park SY, Kim HY, Bae SS, Lee WS, Rhim BY, Hong KW, Kim CD. Cilostazol Upregulates Autophagy via SIRT1 Activation: Reducing Amyloid-β Peptide and APP-CTFβ Levels in Neuronal Cells. PLoS One 2015; 10:e0134486. [PMID: 26244661 PMCID: PMC4526537 DOI: 10.1371/journal.pone.0134486] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 07/10/2015] [Indexed: 11/26/2022] Open
Abstract
Autophagy is a vital pathway for the removal of β-amyloid peptide (Aβ) and the aggregated proteins that cause Alzheimer’s disease (AD). We previously found that cilostazol induced SIRT1 expression and its activity in neuronal cells, and thus, we hypothesized that cilostazol might stimulate clearances of Aβ and C-terminal APP fragment β subunit (APP-CTFβ) by up-regulating autophagy.When N2a cells were exposed to soluble Aβ1–42, protein levels of beclin-1, autophagy-related protein5 (Atg5), and SIRT1 decreased significantly. Pretreatment with cilostazol (10–30 μM) or resveratrol (20 μM) prevented these Aβ1–42 evoked suppressions. LC3-II (a marker of mammalian autophagy) levels were significantly increased by cilostazol, and this increase was reduced by 3-methyladenine. To evoke endogenous Aβ overproduction, N2aSwe cells (N2a cells stably expressing human APP containing the Swedish mutation) were cultured in medium with or without tetracycline (Tet+ for 48 h and then placed in Tet- condition). Aβ and APP-CTFβ expressions were increased after 12~24 h in Tet- condition, and these increased expressions were significantly reduced by pretreating cilostazol. Cilostazol-induced reductions in the expressions of Aβ and APP-CTFβ were blocked by bafilomycin A1 (a blocker of autophagosome to lysosome fusion). After knockdown of the SIRT1 gene (to ~40% in SIRT1 protein), cilostazol failed to elevate the expressions of beclin-1, Atg5, and LC3-II, indicating that cilostazol increases these expressions by up-regulating SIRT1. Further, decreased cell viability induced by Aβ was prevented by cilostazol, and this inhibition was reversed by 3-methyladenine, indicating that the protective effect of cilostazol against Aβ induced neurotoxicity is, in part, ascribable to the induction of autophagy. In conclusion, cilostazol modulates autophagy by increasing the activation of SIRT1, and thereby enhances Aβ clearance and increases cell viability.
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Affiliation(s)
- Hye Rin Lee
- Gene & Cell Therapy Research Center for Vessel-associated Diseases, Pusan National University, Yangsan-si, Gyeongsangnam-do, Republic of Korea
- Medical Research Center for Ischemic Tissue Regeneration, Pusan National University, Yangsan-si, Gyeongsangnam-do, Republic of Korea
| | - Hwa Kyoung Shin
- Division of Meridian and Structural Medicine, School of Korean Medicine, Pusan National University, Yangsan-si, Gyeongsangnam-do, Republic of Korea
| | - So Youn Park
- Gene & Cell Therapy Research Center for Vessel-associated Diseases, Pusan National University, Yangsan-si, Gyeongsangnam-do, Republic of Korea
- Medical Research Center for Ischemic Tissue Regeneration, Pusan National University, Yangsan-si, Gyeongsangnam-do, Republic of Korea
| | - Hye Young Kim
- Medical Research Center for Ischemic Tissue Regeneration, Pusan National University, Yangsan-si, Gyeongsangnam-do, Republic of Korea
| | - Sun Sik Bae
- Department of Pharmacology, School of Medicine, Pusan National University, Yangsan-si, Gyeongsangnam-do, Republic of Korea
- Gene & Cell Therapy Research Center for Vessel-associated Diseases, Pusan National University, Yangsan-si, Gyeongsangnam-do, Republic of Korea
| | - Won Suk Lee
- Department of Pharmacology, School of Medicine, Pusan National University, Yangsan-si, Gyeongsangnam-do, Republic of Korea
| | - Byung Yong Rhim
- Department of Pharmacology, School of Medicine, Pusan National University, Yangsan-si, Gyeongsangnam-do, Republic of Korea
| | - Ki Whan Hong
- Gene & Cell Therapy Research Center for Vessel-associated Diseases, Pusan National University, Yangsan-si, Gyeongsangnam-do, Republic of Korea
- Medical Research Center for Ischemic Tissue Regeneration, Pusan National University, Yangsan-si, Gyeongsangnam-do, Republic of Korea
| | - Chi Dae Kim
- Department of Pharmacology, School of Medicine, Pusan National University, Yangsan-si, Gyeongsangnam-do, Republic of Korea
- Gene & Cell Therapy Research Center for Vessel-associated Diseases, Pusan National University, Yangsan-si, Gyeongsangnam-do, Republic of Korea
- Medical Research Center for Ischemic Tissue Regeneration, Pusan National University, Yangsan-si, Gyeongsangnam-do, Republic of Korea
- * E-mail:
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9
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Matz A, Halamoda-Kenzaoui B, Hamelin R, Mosser S, Alattia JR, Dimitrov M, Moniatte M, Fraering PC. Identification of new Presenilin-1 phosphosites: implication for γ-secretase activity and Aβ production. J Neurochem 2015; 133:409-21. [PMID: 25458374 DOI: 10.1111/jnc.12996] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 11/02/2014] [Accepted: 11/10/2014] [Indexed: 02/02/2023]
Abstract
An important pathological hallmark of Alzheimer's disease (AD) is the deposition of amyloid-beta (Aβ) peptides in the brain parenchyma, leading to neuronal death and impaired learning and memory. The protease γ-secretase is responsible for the intramembrane proteolysis of the amyloid-β precursor protein (APP), which leads to the production of the toxic Aβ peptides. Thus, an attractive therapeutic strategy to treat AD is the modulation of the γ-secretase activity, to reduce Aβ42 production. Because phosphorylation of proteins is a post-translational modification known to modulate the activity of many different enzymes, we used electrospray (LC-MS/MS) mass spectrometry to identify new phosphosites on highly purified human γ-secretase. We identified 11 new single or double phosphosites in two well-defined domains of Presenilin-1 (PS1), the catalytic subunit of the γ-secretase complex. Next, mutagenesis and biochemical approaches were used to investigate the role of each phosphosite in the maturation and activity of γ-secretase. Together, our results suggest that the newly identified phosphorylation sites in PS1 do not modulate γ-secretase activity and the production of the Alzheimer's Aβ peptides. Individual PS1 phosphosites shall probably not be considered therapeutic targets for reducing cerebral Aβ plaque formation in AD. In this study, we identified 11 new phosphosites in Presenilin-1 (PS1), the catalytic subunit of the Alzheimer's γ-secretase complex. By combining a mutagenesis approach with cell-based and cell-free γ-secretase assays, we demonstrate that the new phosphosites do not modulate the maturation and activity of γ-secretase. Individual PS1 phosphosites shall thus not be considered therapeutic targets for reducing cerebral Aβ plaque formation in Alzheimer's Disease. Aβ, amyloid beta.
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Affiliation(s)
- Alexandre Matz
- Brain Mind Institute and School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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10
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Presenilin/γ-secretase regulates neurexin processing at synapses. PLoS One 2011; 6:e19430. [PMID: 21559374 PMCID: PMC3084856 DOI: 10.1371/journal.pone.0019430] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Accepted: 04/04/2011] [Indexed: 12/21/2022] Open
Abstract
Neurexins are a large family of neuronal plasma membrane proteins, which function as trans-synaptic receptors during synaptic differentiation. The binding of presynaptic neurexins to postsynaptic partners, such as neuroligins, has been proposed to participate in a signaling pathway that regulates synapse formation/stabilization. The identification of mutations in neurexin genes associated with autism and mental retardation suggests that dysfunction of neurexins may underlie synaptic defects associated with brain disorders. However, the mechanisms that regulate neurexin function at synapses are still unclear. Here, we show that neurexins are proteolytically processed by presenilins (PS), the catalytic components of the γ-secretase complex that mediates the intramembraneous cleavage of several type I membrane proteins. Inhibition of PS/γ-secretase by using pharmacological and genetic approaches induces a drastic accumulation of neurexin C-terminal fragments (CTFs) in cultured rat hippocampal neurons and mouse brain. Neurexin-CTFs accumulate mainly at the presynaptic terminals of PS conditional double knockout (PS cDKO) mice lacking both PS genes in glutamatergic neurons of the forebrain. The fact that loss of PS function enhances neurexin accumulation at glutamatergic terminals mediated by neuroligin-1 suggests that PS regulate the processing of neurexins at glutamatergic synapses. Interestingly, presenilin 1 (PS1) is recruited to glutamatergic terminals mediated by neuroligin-1, thus concentrating PS1 at terminals containing β-neurexins. Furthermore, familial Alzheimer's disease (FAD)-linked PS1 mutations differentially affect β-neurexin-1 processing. Expression of PS1 M146L and PS1 H163R mutants in PS−/− cells rescues the processing of β-neurexin-1, whereas PS1 C410Y and PS1 ΔE9 fail to rescue the processing defect. These results suggest that PS regulate the synaptic function and processing of neurexins at glutamatergic synapses, and that impaired neurexin processing by PS may play a role in FAD.
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11
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Three-amino acid spacing of presenilin endoproteolysis suggests a general stepwise cleavage of gamma-secretase-mediated intramembrane proteolysis. J Neurosci 2010; 30:7853-62. [PMID: 20534834 DOI: 10.1523/jneurosci.1443-10.2010] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Presenilin (PS1 or PS2) is the catalytic component of the gamma-secretase complex, which mediates the final proteolytic processing step leading to the Alzheimer's disease (AD)-characterizing amyloid beta-peptide. PS is cleaved during complex assembly into its characteristic N- and C-terminal fragments. Both fragments are integral components of physiologically active gamma-secretase and harbor the two critical aspartyl residues of the active site domain. While the minimal subunit composition of gamma-secretase has been defined and numerous substrates were identified, the cellular mechanism of the endoproteolytic cleavage of PS is still unclear. We addressed this pivotal question by investigating whether familial AD (FAD)-associated PS1 mutations affect the precision of PS endoproteolysis in a manner similar to the way that such mutations shift the intramembrane cleavage of gamma-secretase substrates. We demonstrate that all FAD mutations investigated still allow endoproteolysis to occur. However, the precision of PS1 endoproteolysis is affected by PS1 mutations. Comparing the cleavage products generated by a variety of PS1 mutants revealed that specifically cleavages at positions 293 and 296 of PS1 are selectively affected. Systematic mutagenesis around the cleavage sites revealed a stepwise three amino acid spaced cleavage mechanism of PS endoproteolysis reminiscent to the epsilon-, zeta-, and gamma-cleavages described for typical gamma-secretase substrates, such as the beta-amyloid precursor protein. Our findings therefore suggest that intramembranous cleavage by gamma-secretase and related intramembrane-cleaving proteases may generally occur via stepwise endoproteolysis.
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12
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Watanabe N, Image Image II, Takagi S, Image Image II, Tominaga A, Image Image I, Tomita T, Image Image II, Iwatsubo T, Image Image I. Functional analysis of the transmembrane domains of presenilin 1: participation of transmembrane domains 2 and 6 in the formation of initial substrate-binding site of gamma-secretase. J Biol Chem 2010; 285:19738-46. [PMID: 20418378 DOI: 10.1074/jbc.m110.101287] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
gamma-Secretase is a multimeric membrane protein complex composed of presenilin (PS), nicastrin, Aph-1, and Pen-2, which mediates intramembrane proteolysis of a range of type I transmembrane proteins. We previously analyzed the functional roles of the N-terminal transmembrane domains (TMDs) 1-6 of PS1 in the assembly and proteolytic activity of the gamma-secretase using a series of TMD-swap PS1 mutants. Here we applied the TMD-swap method to all the TMDs of PS1 for the structure-function analysis of the proteolytic mechanism of gamma-secretase. We found that TMD2- or -6-swapped mutant PS1 failed to bind the helical peptide-based, substrate-mimic gamma-secretase inhibitor. Cross-linking experiments revealed that both TMD2 and TMD6 of PS1 locate in proximity to the TMD9, the latter being implicated in the initial substrate binding. Taken together, our data suggest that TMD2 and the luminal side of TMD6 are involved in the formation of the initial substrate-binding site of the gamma-secretase complex.
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Affiliation(s)
- Naoto Watanabe
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
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13
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Rocher-Ros V, Marco S, Mao JH, Gines S, Metzger D, Chambon P, Balmain A, Saura CA. Presenilin modulates EGFR signaling and cell transformation by regulating the ubiquitin ligase Fbw7. Oncogene 2010; 29:2950-61. [PMID: 20208556 DOI: 10.1038/onc.2010.57] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The epidermal growth factor receptor (EGFR) and Notch signaling pathways have antagonistic roles during epidermal differentiation and carcinogenesis. The molecular mechanisms regulating the crosstalk between EGFR and Notch during epidermal transformation are largely unknown. We found enhanced EGFR-dependent signaling, proliferation and oncogenic transformation caused by loss of presenilins (PS), the catalytic components of gamma-secretase that generates the Notch1 intracellular domain (NICD). The underlying mechanism for abnormal EGFR signaling in PS-deficient cells involves gamma-secretase-independent transcriptional upregulation of the E3 ubiquitin ligase Fbw7. Fbw7alpha, which targets NICD for degradation, regulates positively EGFR by affecting a proteasome-dependent ubiquitination step essential for constitutive degradation and stability of EGFR. To investigate the pathological relevance of this findings in vivo, we generated a novel epidermal conditional PS-deficient (ePS cDKO) mouse by deleting both PS in keratinocytes of the basal layer of the epidermis. The ePS cDKO mice develop epidermal hyperplasia associated with enhanced expression of both EGFR and Fbw7 and reduced NICD levels in keratinocytes. These findings establish a novel role for PS on epidermal growth and transformation by reciprocally regulating the EGFR and Notch signaling pathways through Fbw7.
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Affiliation(s)
- V Rocher-Ros
- Institut de Neurociències, Department de Bioquímica i Biologia Molecular, Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas, Universitat Autònoma de Barcelona, Barcelona 08193, Spain
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14
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Wanngren J, Frånberg J, Svensson AI, Laudon H, Olsson F, Winblad B, Liu F, Näslund J, Lundkvist J, Karlström H. The large hydrophilic loop of presenilin 1 is important for regulating gamma-secretase complex assembly and dictating the amyloid beta peptide (Abeta) Profile without affecting Notch processing. J Biol Chem 2010; 285:8527-36. [PMID: 20106965 DOI: 10.1074/jbc.m109.055590] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Gamma-secretase is an enzyme complex that mediates both Notch signaling and beta-amyloid precursor protein (APP) processing, resulting in the generation of Notch intracellular domain, APP intracellular domain, and the amyloid beta peptide (Abeta), the latter playing a central role in Alzheimer disease (AD). By a hitherto undefined mechanism, the activity of gamma-secretase gives rise to Abeta peptides of different lengths, where Abeta42 is considered to play a particular role in AD. In this study we have examined the role of the large hydrophilic loop (amino acids 320-374, encoded by exon 10) of presenilin 1 (PS1), the catalytic subunit of gamma-secretase, for gamma-secretase complex formation and activity on Notch and APP processing. Deletion of exon 10 resulted in impaired PS1 endoproteolysis, gamma-secretase complex formation, and had a differential effect on Abeta-peptide production. Although the production of Abeta38, Abeta39, and Abeta40 was severely impaired, the effect on Abeta42 was affected to a lesser extent, implying that the production of the AD-related Abeta42 peptide is separate from the production of the Abeta38, Abeta39, and Abeta40 peptides. Interestingly, formation of the intracellular domains of both APP and Notch was intact, implying a differential cleavage activity between the epsilon/S3 and gamma sites. The most C-terminal amino acids of the hydrophilic loop were important for regulating APP processing. In summary, the large hydrophilic loop of PS1 appears to differentially regulate the relative production of different Abeta peptides without affecting Notch processing, two parameters of significance when considering gamma-secretase as a target for pharmaceutical intervention in AD.
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Affiliation(s)
- Johanna Wanngren
- Department of Neurobiology, Caring Sciences and Society, KI-Alzheimer Disease Research Center, Karolinska Institutet, Novum, SE-141 86 Stockholm, Sweden
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15
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An alternative spliced mouse presenilin-2 mRNA encodes a novel gamma-secretase inhibitor. FEBS Lett 2009; 583:1403-8. [PMID: 19376115 DOI: 10.1016/j.febslet.2009.04.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Revised: 04/02/2009] [Accepted: 04/03/2009] [Indexed: 12/23/2022]
Abstract
The gamma-secretase, composed of presenilin-1 (PS1) or presenilin-2 (PS2), nicastrin (NCT), anterior pharynx-defective phenotype 1 (APH-1), and PEN-2, is critical for the development of Alzheimer's disease (AD). PSs are autoproteolytically cleaved, producing an N-terminal fragment (NTF) and a hydrophilic loop domain-containing C-terminal fragment. However, the role of the loop domain in the gamma-secretase complex assembly remains unknown. Here, we report a novel PS2 isoform generated by alternative splicing, named PS2beta, which is composed of an NTF with a hydrophilic loop domain. PS2beta disturbed the interaction between NCT and APH-1, resulting in the inhibition of amyloid-beta production. We concluded that PS2beta may inhibit gamma-secretase activity by affecting the gamma-secretase complex assembly.
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16
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Raurell I, Codina M, Casagolda D, del Valle B, Baulida J, de Herreros AG, Duñach M. Gamma-secretase-dependent and -independent effects of presenilin1 on beta-catenin.Tcf-4 transcriptional activity. PLoS One 2008; 3:e4080. [PMID: 19114997 PMCID: PMC2603589 DOI: 10.1371/journal.pone.0004080] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2008] [Accepted: 11/27/2008] [Indexed: 11/18/2022] Open
Abstract
Presenilin1 (PS1) is a component of the gamma-secretase complex mutated in cases of Familial Alzheimer's disease (FAD). PS1 is synthesized as a 50 kDa peptide subsequently processed to two 29 and 20 kDa subunits that remain associated. Processing of PS1 is inhibited by several mutations detected in FAD patients. PS1 acts as negative modulator of beta-catenin.Tcf-4 transcriptional activity. In this article we show that in murine embryonic fibroblasts (MEFs) the mechanisms of action of the processed and non-processed forms of PS1 on beta-catenin.Tcf-4 transcription are different. Whereas non-processed PS1 inhibits beta-catenin.Tcf-4 activity through a mechanism independent of gamma-secretase and associated with the interaction of this protein with plakoglobin and Tcf-4, the effect of processed PS1 is prevented by gamma-secretase inhibitors, and requires its interaction with E- or N-cadherin and the generation of cytosolic terminal fragments of these two cadherins, which in turn destabilize the beta-catenin transcriptional cofactor CBP. Accordingly, the two forms of PS1 interact differently with E-cadherin or beta-catenin and plakoglobin: whereas processed PS1 binds E-cadherin with high affinity and beta-catenin or plakoglobin weakly, the non-processed form behaves inversely. Moreover, contrarily to processed PS1, that decreases the levels of c-fos RNA, non-processed PS1 inhibits the expression c-myc, a known target of beta-catenin.Tcf-4, and does not block the activity of other transcriptional factors requiring CBP. These results indicate that prevention of PS1 processing in FAD affects the mechanism of repression of the transcriptional activity dependent on beta-catenin.
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Affiliation(s)
- Imma Raurell
- Unitat de Biofísica-CEB, Departament de Bioquímica i Biologia Molecular, Facultat Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Montserrat Codina
- Unitat de Biofísica-CEB, Departament de Bioquímica i Biologia Molecular, Facultat Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Programa de Recerca en Càncer, IMIM-Hospital del Mar, Barcelona, Spain
| | - David Casagolda
- Unitat de Biofísica-CEB, Departament de Bioquímica i Biologia Molecular, Facultat Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Beatriz del Valle
- Unitat de Biofísica-CEB, Departament de Bioquímica i Biologia Molecular, Facultat Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Josep Baulida
- Programa de Recerca en Càncer, IMIM-Hospital del Mar, Barcelona, Spain
| | - Antonio García de Herreros
- Programa de Recerca en Càncer, IMIM-Hospital del Mar, Barcelona, Spain
- Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain
- * E-mail: (MD); (AGdH)
| | - Mireia Duñach
- Unitat de Biofísica-CEB, Departament de Bioquímica i Biologia Molecular, Facultat Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
- * E-mail: (MD); (AGdH)
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17
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Structure and function of gamma-secretase. Semin Cell Dev Biol 2008; 20:211-8. [PMID: 19007897 DOI: 10.1016/j.semcdb.2008.10.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Accepted: 10/13/2008] [Indexed: 11/22/2022]
Abstract
The gamma-secretase complex is a prime target for pharmacological intervention in Alzheimer's disease and so far drug discovery efforts have yielded a large variety of potent and rather specific inhibitors of this enzymatic activity. However, as gamma-secretase is able to cleave a wide variety of physiological important substrates, the real challenge is to develop substrate-specific compounds. Therefore, obtaining structural information about gamma-secretase is indispensable. As crystal structures of the complex will be difficult to achieve, applied biochemical approaches need to be integrated with structural information obtained from other intramembrane-cleaving proteases. Here we review current knowledge about the structure and function of gamma-secretase and discuss the value of these findings for the mechanistic understanding of this unusual protease.
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18
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Kuo LH, Hu MK, Hsu WM, Tung YT, Wang BJ, Tsai WW, Yen CT, Liao YF. Tumor necrosis factor-alpha-elicited stimulation of gamma-secretase is mediated by c-Jun N-terminal kinase-dependent phosphorylation of presenilin and nicastrin. Mol Biol Cell 2008; 19:4201-12. [PMID: 18667537 DOI: 10.1091/mbc.e07-09-0987] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Gamma-secretase is a multiprotein complex composed of presenilin (PS), nicastrin (NCT), Aph-1, and Pen-2, and it catalyzes the final proteolytic step in the processing of amyloid precursor protein to generate amyloid-beta. Our previous results showed that tumor necrosis factor-alpha (TNF-alpha) can potently stimulate gamma-secretase activity through a c-Jun N-terminal kinase (JNK)-dependent pathway. Here, we demonstrate that TNF-alpha triggers JNK-dependent serine/threonine phosphorylation of PS1 and NCT to stimulate gamma-secretase activity. Blocking of JNK activity with a potent JNK inhibitor (SP600125) reduces TNF-alpha-triggered phosphorylation of PS1 and NCT. Consistent with this, we show that activated JNKs can be copurified with gamma-secretase complexes and that active recombinant JNK2 can promote the phosphorylation of PS1 and NCT in vitro. Using site-directed mutagenesis and a synthetic peptide, we clearly show that the Ser(319)Thr(320) motif in PS1 is an important JNK phosphorylation site that is critical for the TNF-alpha-elicited regulation of gamma-secretase. This JNK phosphorylation of PS1 at Ser(319)Thr(320) enhances the stability of the PS1 C-terminal fragment that is necessary for gamma-secretase activity. Together, our findings strongly suggest that JNK is a critical intracellular mediator of TNF-alpha-elicited regulation of gamma-secretase and governs the pivotal step in the assembly of functional gamma-secretase.
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Affiliation(s)
- Lan-Hsin Kuo
- Laboratory of Molecular Neurobiology, Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan
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19
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Prager K, Wang-Eckhardt L, Fluhrer R, Killick R, Barth E, Hampel H, Haass C, Walter J. A Structural Switch of Presenilin 1 by Glycogen Synthase Kinase 3β-mediated Phosphorylation Regulates the Interaction with β-Catenin and Its Nuclear Signaling. J Biol Chem 2007; 282:14083-93. [PMID: 17360711 DOI: 10.1074/jbc.m608437200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Presenilins (PS) are critical components of the gamma-secretase complex that mediates cleavage of type I membrane proteins including the beta-amyloid precursor protein to generate the amyloid beta-peptide. In addition, PS1 interacts with beta-catenin and facilitates its metabolism. We demonstrate that phosphorylation of serines 353 and 357 by glycogen synthase kinase-3beta (GSK3beta) induces a structural change of the hydrophilic loop of PS1 that can also be mimicked by substitution of the phosphorylation sites by negatively charged amino acids in vitro and in cultured cells. The structural change of PS1 reduces the interaction with beta-catenin leading to decreased phosphorylation and ubiquitination of beta-catenin. The decreased interaction of PS1 with beta-catenin leads to stabilization of beta-catenin thereby increasing its nuclear signaling and the transcription of target genes, including c-MYC. Consistent with increased expression of c-myc, a PS1 mutant that mimics phosphorylated PS1 increased cell proliferation as compared with wild-type PS1. These results indicate a regulatory mechanism in which GSK3beta-mediated phosphorylation induces a structural change of the hydrophilic loop of PS1 thereby negatively modulating the formation of a ternary complex between beta-catenin, PS1, and GSK3beta, which leads to stabilization of beta-catenin.
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Affiliation(s)
- Kai Prager
- Department of Neurology, University of Bonn, Bonn, Germany
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20
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Abstract
Gamma-secretase is responsible for the proteolytic processing of a variety of membrane-associated fragments derived from type I integral membrane proteins, including the amyloid beta-protein precursor and the Notch receptor. This enzyme is composed of four different integral membrane proteins: presenilin, nicastrin, Aph-1, and Pen-2. During assembly and maturation of the protease complex, presenilin is endoproteolyzed into two subunits, each of which contributes one aspartate to the active site of an aspartyl protease. Substrate apparently interacts with an initial docking site before passing in whole or in part between the two presenilin subunits to the internal water-containing active site. The ectodomain of nicastrin also interacts with the N-terminus of the substrate as an essential step in substrate recognition and processing. Sites for allosteric regulation on the protease complex allow selective inhibition or modulation of APP processing without interfering with Notch signaling, and such selective agents may represent promising leads for the development of Alzheimer's disease therapeutics. Elucidation of detailed structural features of gamma-secretase and other membrane-embedded proteases is the next frontier in understanding how these enzymes carry out hydrolysis within the lipid bilayer.
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Affiliation(s)
- Michael S Wolfe
- Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
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21
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Vetrivel KS, Zhang YW, Xu H, Thinakaran G. Pathological and physiological functions of presenilins. Mol Neurodegener 2006; 1:4. [PMID: 16930451 PMCID: PMC1513131 DOI: 10.1186/1750-1326-1-4] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Accepted: 06/12/2006] [Indexed: 11/16/2022] Open
Abstract
Mutations in PSEN1 and PSEN2 genes account for the majority of cases of early-onset familial Alzheimer disease. Since the first prediction of a genetic link between PSEN1 and PSEN2 with Alzheimer's disease, many research groups from both academia and pharmaceutical industry have sought to unravel how pathogenic mutations in PSEN cause presenile dementia. PSEN genes encode polytopic membrane proteins termed presenilins (PS1 and PS2), which function as the catalytic subunit of γ-secretase, an intramembrane protease that has a wide spectrum of type I membrane protein substrates. Sequential cleavage of amyloid precursor protein by BACE and γ-secretase releases highly fibrillogenic β-amyloid peptides, which accumulate in the brains of aged individuals and patients with Alzheimer's disease. Familial Alzheimer's disease-associated presenilin variants are thought to exert their pathogenic function by selectively elevating the levels of highly amyloidogenic Aβ42 peptides. In addition to Alzheimer's disease, several recent studies have linked PSEN1 to familiar frontotemporal dementia. Here, we review the biology of PS1, its role in γ-secretase activity, and discuss recent developments in the cell biology of PS1 with respect to Alzheimer's disease pathogenesis.
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Affiliation(s)
- Kulandaivelu S Vetrivel
- Department of Neurobiology, Pharmacology and Physiology, The University of Chicago, Chicago, IL 60637, USA
| | - Yun-wu Zhang
- Center for Neuroscience and Aging, Burnham Institute for Medical Research, LaJolla, CA 92037, USA
| | - Huaxi Xu
- Center for Neuroscience and Aging, Burnham Institute for Medical Research, LaJolla, CA 92037, USA
| | - Gopal Thinakaran
- Department of Neurobiology, Pharmacology and Physiology, The University of Chicago, Chicago, IL 60637, USA
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22
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Morohashi Y, Kan T, Tominari Y, Fuwa H, Okamura Y, Watanabe N, Sato C, Natsugari H, Fukuyama T, Iwatsubo T, Tomita T. C-terminal Fragment of Presenilin Is the Molecular Target of a Dipeptidic γ-Secretase-specific Inhibitor DAPT (N-[N-(3,5-Difluorophenacetyl)-L-alanyl]-S-phenylglycine t-Butyl Ester). J Biol Chem 2006; 281:14670-6. [PMID: 16569643 DOI: 10.1074/jbc.m513012200] [Citation(s) in RCA: 158] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gamma-secretase is a multimeric membrane protein complex composed of presenilin (PS), nicastrin, Aph-1 and, Pen-2 that is responsible for the intramembrane proteolysis of various type I transmembrane proteins, including amyloid beta-precursor protein and Notch. The direct labeling of PS polypeptides by transition-state analogue gamma-secretase inhibitors suggested that PS represents the catalytic center of gamma-secretase. Here we show that one of the major gamma-secretase inhibitors of dipeptidic type, N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT), targets the C-terminal fragment of PS, especially the transmembrane domain 7 or more C-terminal region, by designing and synthesizing DAP-BpB (N-[N-(3,5-difluorophenacetyl)-l-alanyl]-(S)-phenylglycine-4-(4-(8-biotinamido)octylamino)benzoyl)benzyl)methylamide), a photoactivable DAPT derivative. We also found that DAP-BpB selectively binds to the high molecular weight gamma-secretase complex in an activity-dependent manner. Photolabeling of PS by DAP-BpB is completely blocked by DAPT or its structural relatives (e.g. Compound E) as well as by arylsulfonamides. In contrast, transition-state analogue inhibitor L-685,458 or alpha-helical peptidic inhibitor attenuated the photolabeling of PS1 only at higher concentrations. These data illustrate the DAPT binding site as a novel functional domain within the PS C-terminal fragment that is distinct from the catalytic site or the substrate binding site.
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Affiliation(s)
- Yuichi Morohashi
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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23
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Deng Y, Tarassishin L, Kallhoff V, Peethumnongsin E, Wu L, Li YM, Zheng H. Deletion of presenilin 1 hydrophilic loop sequence leads to impaired gamma-secretase activity and exacerbated amyloid pathology. J Neurosci 2006; 26:3845-54. [PMID: 16597739 PMCID: PMC6674120 DOI: 10.1523/jneurosci.5384-05.2006] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
gamma-Secretase processing of the amyloid precursor protein (APP) generates Abeta40 and Abeta42, peptides that constitute the principal components of the beta-amyloid plaque pathology of Alzheimer's disease (AD). The gamma-secretase activity is executed by a high-molecular-weight complex of which presenilin 1 (PS1) is an essential component. PS1 is a multi-pass membrane protein, and the large hydrophilic loop domain between transmembrane domains 6 and 7 has been shown to interact with various proteins. To determine the physiological function of the loop domain, we created a strain of PS1 knock-in mice in which the exon 10, which encodes most of the hydrophilic loop sequence, was deleted from the endogenous PS1 gene. We report here that the homozygous exon 10-deleted mice are viable but exhibit drastically reduced gamma-secretase cleavage at the Abeta40, but not the Abeta42, site. Surprisingly, this reduction of Abeta40 is associated with exacerbated plaque pathology when expressed on APP transgenic background. Thus, the PS1 loop plays a regulatory role in gamma-secretase processing, and decreased Abeta40, not increased Abeta42 is likely the cause for the accelerated plaque deposition in these animals. Our finding supports a protective role of Abeta40 against amyloid pathology and raises the possibility that impaired gamma-secretase activity could be the basis for AD pathogenesis in general.
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24
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Hansson CA, Popescu BO, Laudon H, Cedazo-Minguez A, Popescu LM, Winblad B, Ankarcrona M. Caspase cleaved presenilin-1 is part of active gamma-secretase complexes. J Neurochem 2006; 97:356-64. [PMID: 16539675 DOI: 10.1111/j.1471-4159.2006.03735.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
gamma-Secretase is a key enzyme involved in the processing of the beta-amyloid precursor protein into amyloid beta-peptides (Abeta). Abeta accumulates and forms plaques in Alzheimer's disease (AD) brains. A progressive neurodegeneration and cognitive decline occurs during the course of the disease, and Abeta is believed to be central for the molecular pathogenesis of AD. Apoptosis has been implicated as one of the mechanisms behind the neuronal cell loss seen in AD. We have studied preservation and activity of the gamma-secretase complex during apoptosis in neuroblastoma cells (SH-SY5Y) exposed to staurosporine (STS). We report that the known components (presenilin, Nicastrin, Aph-1 and Pen-2) interact and form active gamma-secretase complexes in apoptotic cells. In addition, the fragments corresponding to the PS1 N-terminal fragment and the caspase-cleaved PS1 C-terminal fragment (PS1-caspCTF) were found to form active gamma-secretase complexes when co-expressed in presenilin (PS) knockout cells. Interestingly, PS1-caspCTF replaced the normal PS1 C-terminal fragment and was co-immunoprecipitated with the gamma-secretase complex in SH-SY5Y cells exposed to STS. In addition, Abeta was detected in medium from apoptotic HEK APP(swe) cells. Together, the data show that gamma-secretase complexes containing PS1-caspCTF are active, and suggest that this proteolytic activity is also important in dying cells and may affect the progression of AD.
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Affiliation(s)
- Camilla A Hansson
- Karolinska Institutet, Neurotec, Section for Experimental Geriatrics, Huddinge, Sweden
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25
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Watanabe N, Tomita T, Sato C, Kitamura T, Morohashi Y, Iwatsubo T. Pen-2 is incorporated into the gamma-secretase complex through binding to transmembrane domain 4 of presenilin 1. J Biol Chem 2005; 280:41967-75. [PMID: 16234244 DOI: 10.1074/jbc.m509066200] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
gamma-Secretase is a multimeric membrane protein complex comprised of presenilin (PS), nicastrin (Nct), Aph-1, and Pen-2. It is a member of an atypical class of aspartic proteases that hydrolyzes peptide bonds within the membrane. During the biosynthetic process of the gamma-secretase complex, Nct and Aph-1 form a heterodimeric intermediate complex and bind to the C-terminal region of PS, serving as a stabilizing scaffold for the complex. Pen-2 is then recruited into this trimeric complex and triggers endoproteolysis of PS, conferring gamma-secretase activity. Although the Pen-2 accumulation depends on PS, the binding partner of Pen-2 within the gamma-secretase complex remains unknown. We reconstituted PS1 in Psen1/Psen2 deficient cells by expressing a series of PS1 mutants in which one of the N-terminal six transmembrane domains (TMDs) was swapped with those of CD4 (a type I transmembrane protein) or CLAC-P (a type II transmembrane protein). We report that the proximal two-thirds of TMD4 of PS1, including the conserved Trp-Asn-Phe sequence, are required for its interaction with Pen-2. Using a chimeric CD4 molecule harboring PS1 TMD4, we further demonstrate that the PS1 TMD4 bears a direct binding motif to Pen-2. Pen-2 may contribute to the activation of the gamma-secretase complex by directly binding to the TMD4 of PS1.
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Affiliation(s)
- Naoto Watanabe
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Jutras I, Laplante A, Boulais J, Brunet S, Thinakaran G, Desjardins M. γ-Secretase Is a Functional Component of Phagosomes. J Biol Chem 2005; 280:36310-7. [PMID: 16103123 DOI: 10.1074/jbc.m504069200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Gamma-secretase is a high molecular mass protein complex that catalyzes the intramembrane cleavage of its protein substrates. Two proteins involved in phagocytosis, CD44 and the low density lipoprotein receptor-related protein, are gamma-secretase substrates, suggesting that this complex might regulate some aspects of phagocytosis. Our results indicate that the four components of gamma-secretase, viz. presenilin, nicastrin, APH-1, and PEN-2, are present and enriched on phagosome membranes from both murine macrophages and Drosophila S2 phagocytes. The gamma-secretase components form high molecular mass complexes in lipid microdomains of the phagosome membrane with the topology expected for the functional enzyme. In contrast to the majority of the phagosome proteins studied so far, which appear to associate transiently with this organelle, gamma-secretase resides on newly formed phagosomes and remains associated throughout their maturation into phagolysosomes. Finally, our results indicate that interferon-gamma stimulates gamma-secretase-dependent cleavages on phagosomes and that gamma-secretase activity may be involved in the phagocytic response of macrophages to inflammatory cytokines.
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Affiliation(s)
- Isabelle Jutras
- Département de Pathologie et Biologie Cellulaire, Université de Montréal, Montréal, Québec H3C 3J7, Canada
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Kang DE, Yoon IS, Repetto E, Busse T, Yermian N, Ie L, Koo EH. Presenilins mediate phosphatidylinositol 3-kinase/AKT and ERK activation via select signaling receptors. Selectivity of PS2 in platelet-derived growth factor signaling. J Biol Chem 2005; 280:31537-47. [PMID: 16014629 DOI: 10.1074/jbc.m500833200] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The Alzheimer's disease-linked genes, PS1 and PS2, are required for intramembrane proteolysis of multiple type I proteins, including Notch and amyloid precursor protein. In addition, it has been documented that PS1 positively regulates, whereas PS1 familial Alzheimer disease mutations suppress, phosphatidylinositol 3-kinase (PI3K)/Akt activation, a pathway known to inactivate glycogen synthase kinase-3 and reduce tau phosphorylation. In this study, we show that the loss of presenilins not only inhibits PI3K/Akt signaling and increases tau phosphorylation but also suppresses the MEK/ERK pathway. The deficits in Akt and ERK activation in cells deficient in both PS1 and PS2 (PS-/-) are evident after serum withdrawal and stimulation with fetal bovine serum or ligands of select receptor tyrosine kinases, platelet-derived growth factor receptor beta (PDGFR beta) and PDGFR alpha, but not insulin-like growth factor-1R and epidermal growth factor receptor. The defects in PDGF signaling in PS-/- cells are due to reduced expression of PDGF receptors. Whereas fetal bovine serum-induced Akt activation is reconstituted by both PS1 and PS2 in PS-/- cells, PDGF signaling is selectively restored by PS2 but not PS1 and is dependent on the N-terminal fragment of PS2 but not gamma-secretase activity or the hydrophilic loop of PS2. The rescue of PDGF receptor expression and activation by PS2 is facilitated by FHL2, a PS2-interacting transcriptional co-activator. Finally, we present evidence that PS1 mutations interfere with this PS2-mediated activity by reducing PS2 fragments. These findings highlight important roles of both presenilins in Akt and ERK signaling via select signaling receptors.
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Affiliation(s)
- David E Kang
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093, USA.
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Marambaud P, Robakis NK. Genetic and molecular aspects of Alzheimer's disease shed light on new mechanisms of transcriptional regulation. GENES BRAIN AND BEHAVIOR 2005; 4:134-46. [PMID: 15810902 DOI: 10.1111/j.1601-183x.2005.00086.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Rapid advances made in biological research aimed at understanding the molecular basis of the pathogenesis of Alzheimer's disease have led to the characterization of a novel catalytic activity termed gamma-secretase. First described for its beta-amyloid-producing function, gamma-secretase is now actively studied for its role in a novel signal transduction paradigm, which implicates cell-surface receptor proteolysis and direct surface-to-nucleus signal transduction. gamma-Secretase targets numerous type I protein receptors involved in diverse functions ranging from normal development to neurodegeneration. In this Review we discuss how the study of the genetic and molecular aspects of Alzheimer's disease has revealed a dual role of gamma-secretase in transcriptional regulation and in the pathogenesis of familial Alzheimer's disease.
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Affiliation(s)
- P Marambaud
- Department of Psychiatry and Fishberg Research Center for Neurobiology, Mount Sinai School of Medicine, New York, New York 10029, USA.
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29
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Abstract
Alzheimer's disease (AD) is the most common form of dementia and is characterized pathologically by the accumulation of beta-amyloid (Abeta) plaques and neurofibrillary tangles in the brain. Genetic studies of AD first highlighted the importance of the presenilins (PS). Subsequent functional studies have demonstrated that PS form the catalytic subunit of the gamma-secretase complex that produces the Abeta peptide, confirming the central role of PS in AD biology. Here, we review the studies that have characterized PS function in the gamma-secretase complex in Caenorhabditis elegans, mice and in in vitro cell culture systems, including studies of PS structure, PS interactions with substrates and other gamma-secretase complex members, and the evidence supporting the hypothesis that PS are aspartyl proteases that are active in intramembranous proteolysis. A thorough knowledge of the mechanism of PS cleavage in the context of the gamma-secretase complex will further our understanding of the molecular mechanisms that cause AD, and may allow the development of therapeutics that can alter Abeta production and modify the risk for AD.
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Affiliation(s)
- A L Brunkan
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO 63100, USA
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30
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Garnis C, Campbell J, Davies JJ, Macaulay C, Lam S, Lam WL. Involvement of multiple developmental genes on chromosome 1p in lung tumorigenesis. Hum Mol Genet 2004; 14:475-82. [PMID: 15615770 DOI: 10.1093/hmg/ddi043] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Lung cancer is the leading cause of cancer death in North America. Despite advances in lung cancer treatment, the overall 5 year survival rate for those diagnosed with the disease is bleak presumably due to the late stage of diagnosis. Owing to the difficulty of early detection, preneoplastic specimens are rare. However, studying both preinvasive and invasive stages of disease is necessary to fully understand lung cancer progression. Aberration of chromosome arm 1p is common in lung and other cancers. In this study, we used a genomic array with complete tiling coverage of 1p to profile preinvasive and invasive squamous non-small cell lung carcinoma samples. With this technology, multiple novel submegabase alterations were identified. Three of the 1p alterations harbored genes belonging to gene families known to be involved in cancer development through either the Wnt or the Notch developmental pathways. Our finding of a 0.4 Mb amplified region at 1p36.12 containing WNT4 in preinvasive lung cancer, coupled with the identification of three additional alterations in invasive tumors that also contain genes related to the Notch and Wnt pathways, strongly suggests an intricate role of these pathways in early and late stages of lung cancer development. Furthermore, ectopic expression of DVL1, LRP8 and Notch2 in malignant lung tissue validates the biological impact of these genetic alterations. Importantly, this implication of pathways known only to be activated in fetal lung development lends support to the proposed model of lung cancer ontology whereby tumors arise from dysregulated pleuripotent stem cells.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Biomarkers, Tumor/metabolism
- Chromosomes, Human, Pair 1/genetics
- Dishevelled Proteins
- Gene Expression Profiling
- Gene Expression Regulation, Neoplastic
- Humans
- LDL-Receptor Related Proteins
- Lung Neoplasms/genetics
- Lung Neoplasms/pathology
- Neoplasm Invasiveness/pathology
- Oligonucleotide Array Sequence Analysis
- Phosphoproteins
- Proteins/genetics
- Proteins/metabolism
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism
- Receptor, Notch2
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Receptors, Lipoprotein/genetics
- Receptors, Lipoprotein/metabolism
- Signal Transduction
- Wnt Proteins
- Wnt4 Protein
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Affiliation(s)
- Cathie Garnis
- British Columbia Cancer Research Centre, Vancouver, BC V5Z 1L3, Canada.
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31
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Nagaoka U, Kim K, Jana NR, Doi H, Maruyama M, Mitsui K, Oyama F, Nukina N. Increased expression of p62 in expanded polyglutamine-expressing cells and its association with polyglutamine inclusions. J Neurochem 2004; 91:57-68. [PMID: 15379887 DOI: 10.1111/j.1471-4159.2004.02692.x] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Huntington's disease is a progressive neurodegenerative disorder that is associated with a CAG repeat expansion in the gene encoding huntingtin. We found that a 60-kDa protein was increased in Neuro2a cells expressing the N-terminal portion of huntingtin with expanded polyglutamine. We purified this protein, and, using mass spectrometry, identified it as p62, an ubiquitin-associated domain-containing protein. A specific p62 antibody stained the ubiquitylated polyQ inclusions in expanded polyglutamine-expressing cells, as well as in the brain of the huntingtin exon 1 transgenic mice. Furthermore, the level of p62 protein and mRNA was increased in expanded polyglutamine-expressing cells. We also found that p62 formed aggresome-like inclusions when p62 was increased in normal Neuro2a cells by a proteasome inhibitor. Knock-down of p62 does not affect the formation of aggresomes or polyglutamine inclusions, suggesting that p62 is recruited to the aggresome or inclusions secondary to their formation. These results suggest that p62 may play important roles as a responsive protein to a polyglutamine-induced stress rather than as a cross-linker between ubiquitylated proteins.
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Affiliation(s)
- Utako Nagaoka
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Wako-shi, Saitama, Japan
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32
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Morin PJ, Medina M, Semenov M, Brown AMC, Kosik KS. Wnt-1 expression in PC12 cells induces exon 15 deletion and expression of L-APP. Neurobiol Dis 2004; 16:59-67. [PMID: 15207262 DOI: 10.1016/j.nbd.2004.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2003] [Revised: 11/11/2003] [Accepted: 01/08/2004] [Indexed: 11/20/2022] Open
Abstract
The metabolism of amyloid precursor protein (APP) is central to Alzheimer's disease pathogenesis. Recent data have linked APP and presenilin to the Wnt/wingless signaling pathway. To assess affects of Wnt stimulation on APP isoform expression, we infected PC12 cells and C57MG cells with a retrovirus containing murine Wnt-1. In PC12 cells, Wnt-1 expression is associated with induction of exon 15 deletion from APP mRNA and expression of L-APP. Our data suggest that APP isoform expression is regulated, in part, by the Wnt/wingless signaling pathway.
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Affiliation(s)
- Peter J Morin
- Center for Neurologic Diseases, Brigham and Women's Hospital, Department of Neurology, Harvard Medical School, Boston, MA 02115, USA.
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33
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Affiliation(s)
- Jinoh Kim
- Howard Hughes Medical Institute and Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3203, USA
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34
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Fluhrer R, Friedlein A, Haass C, Walter J. Phosphorylation of Presenilin 1 at the Caspase Recognition Site Regulates Its Proteolytic Processing and the Progression of Apoptosis. J Biol Chem 2004; 279:1585-93. [PMID: 14576165 DOI: 10.1074/jbc.m306653200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Alzheimer's disease-associated presenilin (PS) 1 is intimately involved in gamma-secretase cleavage of beta-amyloid precursor protein and other proteins. In addition, PS1 plays a role in beta-catenin signaling and in the regulation of apoptosis. Here we demonstrate that phosphorylation of PS1 is regulated by two independent signaling pathways involving protein kinase (PK) A and PKC and that both kinases can directly phosphorylate the large hydrophilic domain of PS1 in vitro and in cultured cells. A phosphorylation site at serine residue 346 was identified that is selectively phosphorylated by PKC but not by PKA. This site is localized within a recognition motif for caspases, and phosphorylation strongly inhibits proteolytic processing of PS1 by caspase activity during apoptosis. Moreover, PS1 phosphorylation reduces the progression of apoptosis. Our data indicate that phosphorylation/dephosphorylation at the caspase recognition site provides a mechanism to reversibly regulate properties of PS1 in apoptosis.
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Affiliation(s)
- Regina Fluhrer
- Department of Neurology, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn, Germany
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35
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Selkoe D, Kopan R. Notch and Presenilin: regulated intramembrane proteolysis links development and degeneration. Annu Rev Neurosci 2003; 26:565-97. [PMID: 12730322 DOI: 10.1146/annurev.neuro.26.041002.131334] [Citation(s) in RCA: 533] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Intensive studies of three proteins--Presenilin, Notch, and the amyloid precursor protein (APP)--have led to the recognition of a direct intersection between early development and late-life neurodegeneration. Notch signaling mediates many different intercellular communication events that are essential for determining the fates of neural and nonneural cells during development and in the adult. The Notch receptor acts in a core pathway as a membrane-bound transcription factor that is released to the nucleus by a two-step cleavage mechanism called regulated intramembrane proteolysis (RIP). The second cleavage is effected by Presenilin, an unusual polytopic aspartyl protease that apparently cleaves Notch and numerous other single-transmembrane substrates within the lipid bilayer. Another Presenilin substrate, APP, releases the amyloid ss-protein that can accumulate over time in limbic and association cortices and help initiate Alzheimer's disease. Elucidating the detailed mechanism of Presenilin processing of membrane proteins is important for understanding diverse signal transduction pathways and potentially for treating and preventing Alzheimer's disease.
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Affiliation(s)
- Dennis Selkoe
- Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115, USA.
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36
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Selkoe DJ, Schenk D. Alzheimer's disease: molecular understanding predicts amyloid-based therapeutics. Annu Rev Pharmacol Toxicol 2003; 43:545-84. [PMID: 12415125 DOI: 10.1146/annurev.pharmtox.43.100901.140248] [Citation(s) in RCA: 616] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Degenerative diseases of the brain were long considered among the most obscure and intractable of human maladies. However, recent advances in understanding their mechanisms have brought us to the verge of potential disease-modifying agents. This progress is perhaps best exemplified by the case of Alzheimer's disease. The application of molecular pathology and genetics has led to the recognition that the four genes implicated to date in familial Alzheimer's disease all chronically elevate cerebral levels of the amyloid beta-protein (Abeta). Accordingly, small molecule inhibitors of the beta- and gamma-secretases, the proteases that generate Abeta from its precursor, are under active development, and some have shown in vivo efficacy in mouse models. An alternative approach, active or passive immunization against Abeta, has received extensive pre-clinical validation in mice, but an effective preparation free of significant side effects in humans is still awaited. Several other potential therapies are also reviewed here. If one or more of these varied approaches is ultimately proven to slow or prevent dementia, Alzheimer's disease will become a salient example of the successful application of reductionist biology to the most complex of organs, the human cerebral cortex.
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Affiliation(s)
- Dennis J Selkoe
- Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
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37
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Tezapsidis N, Merz PA, Merz G, Hong H. Microtubular interactions of presenilin direct kinesis of Abeta peptide and its precursors. FASEB J 2003; 17:1322-4. [PMID: 12738804 DOI: 10.1096/fj.02-0980fje] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In our previous study we demonstrated that presenilin 1 (PS1) interacts with cytoplasmic linker protein 170/Restin (CLIP-170/Restin). Herein we show that disruption of the interaction of these proteins within neuronal cell-lines (SY5Y and N2a) can be accomplished by the transfection of vectors that drive the expression of peptide fragments corresponding to their binding domains (BDPs). Interestingly, the disruption of the PS1/CLIP-170 complex is associated with both decreased secretion of endogenous Abeta and decreased uptake of exogenous Abeta from the medium. BDP-expressing cells were also more resistant to surges of Abeta secretion induced by thapsigargin and ionomycin (that elevate intracellular calcium concentrations) and mutations in PS1 linked to familial Alzheimer's disease. Uptake of Abeta by SY5Y cells was amplified when preincubated with ApoE and was mediated through lipoprotein receptor-related protein (LRP). BDP-expressing cells or cells treated with PS1 anti-sense oligonucleotides were less capable of taking up Abeta from the medium compared with controls, indicating that the PS1/CLIP-170 interaction is involved and that PS1 cannot be substituted. In this study, we also mapped the minimum binding domains (mBDPs) of PS1 and CLIP-70 to regions corresponding to the N-terminal end of the large cytoplasmic loop of PS1 and the metal binding motif-containing C-terminal end of CLIP-170. Further, our data obtained from experiments involving in vitro taxol-polymerization of tubulin and confocal immunofluorescence suggest that PS1, via CLIP-170, may serve as an anchor to the microtubules for specific subcellular fractions containing amyloidogenic fragments. Interestingly, Notch is absent from this population of microtubule binding subcellular fractions and its cleavage was unaffected in cells transfected with the PS1-based BDP. This raises the possibility that the interaction of PS1 with CLIP-170 could provide the conceptual basis for anti-amyloidogenic therapeutic strategies with improved specificity. However, this approach may be hampered by a low efficiency, because it may also block Abeta clearance from the interstitial space of the CNS.
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Affiliation(s)
- Nikolaos Tezapsidis
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Department of Pathology, College of Physicians and Surgeons, Columbia University, P&S 15-408, 630 W. 168th St., New York, NY 10032, USA.
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38
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Rocchi A, Pellegrini S, Siciliano G, Murri L. Causative and susceptibility genes for Alzheimer's disease: a review. Brain Res Bull 2003; 61:1-24. [PMID: 12788204 DOI: 10.1016/s0361-9230(03)00067-4] [Citation(s) in RCA: 193] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD) is the most common type of dementia in the elderly population. Three genes have been identified as responsible for the rare early-onset familial form of the disease: the amyloid precursor protein (APP) gene, the presenilin 1 (PSEN1) gene and the presenilin 2 (PSEN2) gene. Mutations in these genes, however, account for less than 5% of the total number of AD cases. The remaining 95% of AD patients are mostly sporadic late-onset cases, with a complex aetiology due to interactions between environmental conditions and genetic features of the individual. In this paper, we review the most important genes supposed to be involved in the pathogenesis of AD, known as susceptibility genes, in an attempt to provide a comprehensive picture of what is known about the genetic mechanisms underlying the onset and progression of AD. Hypotheses about the role of each gene in the pathogenic pathway are discussed, taking into account the functions and molecular features, if known, of the coded protein. A major susceptibility gene, the apolipoprotein E (APOE) gene, found to be associated with sporadic late-onset AD cases and the only one, whose role in AD has been confirmed in numerous studies, will be included in a specific chapter. As the results reported by association studies are conflicting, we conclude that a better understanding of the complex aetiology that underlies AD may be achieved likely through a multidisciplinary approach that combines clinical and neurophysiological characterization of AD subtypes and in vivo functional brain imaging studies with molecular investigations of genetic components.
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Affiliation(s)
- A Rocchi
- Department of Neurosciences, Neurological Clinics, University of Pisa Medical School, Via Roma 67, 56126 Pisa, Italy
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39
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Zaidi NF, Berezovska O, Choi EK, Miller JS, Chan H, Lilliehook C, Hyman BT, Buxbaum JD, Wasco W. Biochemical and immunocytochemical characterization of calsenilin in mouse brain. Neuroscience 2002; 114:247-63. [PMID: 12207970 DOI: 10.1016/s0306-4522(02)00251-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Mutations in the presenilin 1 and 2 genes cause the majority of early onset familial forms of Alzheimer's disease. Here we describe the biochemical and immunohistochemical characterization of calsenilin, a novel calcium binding protein that we have previously shown to interact with presenilins 1 and 2, in mouse brain. The co-immunoprecipitation of endogenous calsenilin and presenilin 1 demonstrates that these proteins are physiologic binding partners. Although calsenilin has been predicted to be a soluble protein, we have found that the majority of it is tightly associated with the cytoplasmic face of intracellular membranes and that it can only be dissociated using harsh treatments such as urea. In addition, we have demonstrated that calsenilin is a developmentally regulated protein that is mainly present in the brain, where it localizes to both the hippocampus and cerebellum. Calsenilin staining co-localized with the somatodendritic marker microtubule-associated protein-2 primarily in the granular cell layer of the cerebellum, indicating that calsenilin expression is primarily neuronal. In primary cultured neurons, calsenilin immunoreactivity was observed in cell bodies as well as in some neuronal processes. Co-localization experiments using specific axonal and dendritic markers indicate that these processes were mainly axonal in nature, although a smaller subset of dendrites also appears to contain calsenilin. In summary, we have established that calsenilin and presenilin 1 can interact at physiologic levels, and that calsenilin is a developmentally regulated protein that is expressed primarily in the cerebellum and hippocampus. Although calsenilin is a soluble protein, it is tightly associated with the membrane. Finally, the expression pattern of calsenilin, which is similar to that of the presenilin(s), suggests that the common locations of these two proteins provide an opportunity for physical interaction in vivo.
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Affiliation(s)
- N F Zaidi
- Genetics and Aging Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 114, 16th Street, Charlestown, MA 02129, USA
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40
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Kaether C, Lammich S, Edbauer D, Ertl M, Rietdorf J, Capell A, Steiner H, Haass C. Presenilin-1 affects trafficking and processing of betaAPP and is targeted in a complex with nicastrin to the plasma membrane. J Cell Biol 2002; 158:551-61. [PMID: 12147673 PMCID: PMC2173840 DOI: 10.1083/jcb.200201123] [Citation(s) in RCA: 159] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Amyloid beta-peptide (Abeta) is generated by the consecutive cleavages of beta- and gamma-secretase. The intramembraneous gamma-secretase cleavage critically depends on the activity of presenilins (PS1 and PS2). Although there is evidence that PSs are aspartyl proteases with gamma-secretase activity, it remains controversial whether their subcellular localization overlaps with the cellular sites of Abeta production. We now demonstrate that biologically active GFP-tagged PS1 as well as endogenous PS1 are targeted to the plasma membrane (PM) of living cells. On the way to the PM, PS1 binds to nicastrin (Nct), an essential component of the gamma-secretase complex. This complex is targeted through the secretory pathway where PS1-bound Nct becomes endoglycosidase H resistant. Moreover, surface-biotinylated Nct can be coimmunoprecipitated with PS1 antibodies, demonstrating that this complex is located to cellular sites with gamma-secretase activity. Inactivating PS1 or PS2 function by mutagenesis of one of the critical aspartate residues or by gamma-secretase inhibitors results in delayed reinternalization of the beta-amyloid precursor protein and its accumulation at the cell surface. Our data suggest that PS is targeted as a biologically active complex with Nct through the secretory pathway to the cell surface and suggest a dual function of PS in gamma-secretase processing and in trafficking.
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Affiliation(s)
- Christoph Kaether
- Adolf-Butenandt-Institute, Department of Biochemistry, Laboratory for Alzheimer's and Parkinson's Disease Research, Ludwig-Maximilians-University, 80336 Munich, Germany
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41
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Xia X, Wang P, Sun X, Soriano S, Shum WK, Yamaguchi H, Trumbauer ME, Takashima A, Koo EH, Zheng H. The aspartate-257 of presenilin 1 is indispensable for mouse development and production of beta-amyloid peptides through beta-catenin-independent mechanisms. Proc Natl Acad Sci U S A 2002; 99:8760-5. [PMID: 12070348 PMCID: PMC124372 DOI: 10.1073/pnas.132045399] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To differentiate multiple activities of presenilin 1 (PS1), we generated transgenic mice expressing two human PS1 alleles: one with the aspartate to alanine mutation at residue 257 (hPS1D257A) that impairs the proteolytic activity of PS1, and the other deleting amino acids 340-371 of the hydrophilic loop sequence (hPS1Deltacat) essential for beta-catenin interaction. We show here that although hPS1Deltacat is fully competent in rescuing the PS1-null lethal phenotype, hPS1D257A does not exhibit developmental activity. hPS1D257A also leads to the concurrent loss of the proteolytic processing of Notch and beta-amyloid precursor protein (APP) and the generation of beta-amyloid peptides (Abeta). Further, by measuring the levels of endogenous Abeta(X-40) and Abeta(X-42) in primary neuronal cultures, we confirmed the concept that PS1 is indispensable for the production of secreted Abeta.
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Affiliation(s)
- Xuefeng Xia
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
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42
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Sai X, Kawamura Y, Kokame K, Yamaguchi H, Shiraishi H, Suzuki R, Suzuki T, Kawaichi M, Miyata T, Kitamura T, De Strooper B, Yanagisawa K, Komano H. Endoplasmic reticulum stress-inducible protein, Herp, enhances presenilin-mediated generation of amyloid beta-protein. J Biol Chem 2002; 277:12915-20. [PMID: 11799129 DOI: 10.1074/jbc.m112372200] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Presenilin (PS) is essential for the gamma-cleavage required for the generation of the C terminus of amyloid beta-protein (Abeta). However, the mechanism underlying PS-mediated gamma-cleavage remains unclear. We have identified Herp cDNA by our newly developed screening method for the isolation of cDNAs that increase the degree of gamma-cleavage. Herp was originally identified as a homocysteine-responsive protein, and its expression is up-regulated by endoplasmic reticulum stress. Herp is an endoplasmic reticulum-localized membrane protein that has a ubiquitin-like domain. Here, we report that a high expression of Herp in cells increases the level of Abeta generation, although not in PS-deficient cells. We found that Herp interacts with both PS1 and PS2. Thus, Herp regulates PS-mediated Abeta generation, possibly through its binding to PS. Immunohistochemical analysis of a normal human brain section with an anti-Herp antibody revealed the exclusive staining of neurons and vascular smooth muscle cells. Moreover, the antibody strongly stained activated microglia in senile plaques in the brain of patients with Alzheimer disease. Taken together, Herp could be involved in Abeta accumulation, including the formation of senile plaques and vascular Abeta deposits.
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Affiliation(s)
- Xiaorei Sai
- Department of Dementia Research, National Institute for Longevity Sciences, 36-3 Gengo, Morioka, Obu, Aichi 474-8522, Japan
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43
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Sisodia SS, St George-Hyslop PH. gamma-Secretase, Notch, Abeta and Alzheimer's disease: where do the presenilins fit in? Nat Rev Neurosci 2002; 3:281-90. [PMID: 11967558 DOI: 10.1038/nrn785] [Citation(s) in RCA: 407] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sangram S Sisodia
- Center for Molecular Neurobiology, Department of Neurobiology, Pharmacology and Physiology, The University of Chicago, Chicago, Illinois 60637, USA
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44
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Annaert WG, Esselens C, Baert V, Boeve C, Snellings G, Cupers P, Craessaerts K, De Strooper B. Interaction with telencephalin and the amyloid precursor protein predicts a ring structure for presenilins. Neuron 2001; 32:579-89. [PMID: 11719200 DOI: 10.1016/s0896-6273(01)00512-8] [Citation(s) in RCA: 156] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The carboxyl terminus of presenilin 1 and 2 (PS1 and PS2) binds to the neuron-specific cell adhesion molecule telencephalin (TLN) in the brain. PS1 deficiency results in the abnormal accumulation of TLN in a yet unidentified intracellular compartment. The first transmembrane domain and carboxyl terminus of PS1 form a binding pocket with the transmembrane domain of TLN. Remarkably, APP binds to the same regions via part of its transmembrane domain encompassing the critical residues mutated in familial Alzheimer's disease. Our data surprisingly indicate a spatial dissociation between the binding site and the proposed catalytic site near the critical aspartates in PSs. They provide important experimental evidence to support a ring structure model for PS.
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Affiliation(s)
- W G Annaert
- Laboratory for Neuronal Cell Biology, Department of Human Genetics, Flanders Interuniversity Institute for Biotechnology, KUL-Gasthuisberg, B-3000 Leuven, Belgium.
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Strooper BD, Annaert W. Presenilins and the intramembrane proteolysis of proteins: facts and fiction. Nat Cell Biol 2001; 3:E221-5. [PMID: 11584280 DOI: 10.1038/ncb1001-e221] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- B D Strooper
- Center for Human Genetics, Neuronal Cell Biology Laboratory, The K.U. Leuven and Flanders Interuniversity Institute for Biotechnology, Herestraat 49 3000 Leuven, Belgium.
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46
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Abstract
Understanding mechanisms involved in the production of Abeta has long been the central focus of cell biologists engaged in molecular AD research. The discovery of two genes that encode homologous polytopic membrane proteins termed Presenilins (PS), has lead to several exciting recent findings on the proteolytic processes responsible for generating the COOH-terminus of Abeta. What we now know is that PS proteins play an important role in Abeta production and are considered one of the therapeutic targets. Here I have reviewed the vast literature on the biology of PS, especially focusing on PS endoproteolysis and the accumulation of stable PS derivatives that are likely the functional units.
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Affiliation(s)
- G Thinakaran
- Department of Neurobiology, Pharmacology and Physiology, Center for Molecular Neurobiology, The University of Chicago, IL 60637, USA.
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47
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Xia X, Qian S, Soriano S, Wu Y, Fletcher AM, Wang XJ, Koo EH, Wu X, Zheng H. Loss of presenilin 1 is associated with enhanced beta-catenin signaling and skin tumorigenesis. Proc Natl Acad Sci U S A 2001; 98:10863-8. [PMID: 11517342 PMCID: PMC58565 DOI: 10.1073/pnas.191284198] [Citation(s) in RCA: 183] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2001] [Indexed: 01/08/2023] Open
Abstract
Presenilin 1 (PS1) is required for the proteolytic processing of Notch and the beta-amyloid precursor protein (APP), molecules that play pivotal roles in cell-fate determination during development and Alzheimer's disease pathogenesis, respectively. In addition, PS1 interacts with beta-catenin and promotes its turnover through independent mechanisms. Consistent with this activity, we report here that PS1 is important in controlling epidermal cell proliferation in vivo. PS1 knockout mice that are rescued through neuronal expression of human PS1 transgene develop spontaneous skin cancers. PS1-null keratinocytes exhibit higher cytosolic beta-catenin and beta-catenin/lymphoid enhancer factor-1/T cell factor (beta-catenin/LEF)-mediated signaling. This effect can be reversed by reintroducing wild-type PS1, but not a PS1 mutant active in Notch processing but defective in beta-catenin binding. Nuclear beta-catenin protein can be detected in tumors. Elevated beta-catenin/LEF signaling is correlated with activation of its downstream target cyclin D1 and accelerated entry from G(1) into S phase of the cell cycle. This report demonstrates a function of PS1 in adult tissues, and our analysis suggests that deregulation of beta-catenin pathway contributes to the skin tumor phenotype.
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Affiliation(s)
- X Xia
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
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48
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Kirschenbaum F, Hsu SC, Cordell B, McCarthy JV. Substitution of a glycogen synthase kinase-3beta phosphorylation site in presenilin 1 separates presenilin function from beta-catenin signaling. J Biol Chem 2001; 276:7366-75. [PMID: 11104755 DOI: 10.1074/jbc.m004697200] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The majority of cases with early onset familial Alzheimer's disease have been attributed to mutations in the presenilin 1 (PS1) gene. PS1 protein is a component of a high molecular weight membrane-bound complex that also contains beta-catenin. The physiological relevance of the association between PS1 and beta-catenin remains controversial. In this study, we report the identification and functional characterization of a highly conserved glycogen synthase kinase-3beta consensus phosphorylation site within the hydrophilic loop domain of PS1. Site-directed mutagenesis, together with in vitro and in vivo phosphorylation assays, indicates that PS1 residues Ser(353) and Ser(357) are glycogen synthase kinase-3beta targets. Substitution of one or both of these residues greatly reduces the ability of PS1 to associate with beta-catenin. By disrupting this interaction, we demonstrate that the association between PS1 and beta-catenin has no effect on Abeta peptide production, beta-catenin stability, or cellular susceptibility to apoptosis. Significantly, in the absence of PS1/beta-catenin association, we found no alteration in beta-catenin signaling using induction of this pathway by exogenous expression of Wnt-1 or beta-catenin and a Tcf/Lef transcriptional assay. These results argue against a pathologically relevant role for the association between PS1 and beta-catenin in familial Alzheimer's disease.
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49
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Affiliation(s)
- B De Strooper
- Center for Human Genetics, Neuronal Cell Biology Laboratory, Katholieke Universiteit Leuven and Flanders Interuniversitary Institute for Biotechnology, 3000 Leuven, Belgium.
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50
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Soriano S, Kang DE, Fu M, Pestell R, Chevallier N, Zheng H, Koo EH. Presenilin 1 negatively regulates beta-catenin/T cell factor/lymphoid enhancer factor-1 signaling independently of beta-amyloid precursor protein and notch processing. J Cell Biol 2001; 152:785-94. [PMID: 11266469 PMCID: PMC2195782 DOI: 10.1083/jcb.152.4.785] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In addition to its documented role in the proteolytic processing of Notch-1 and the beta-amyloid precursor protein, presenilin 1 (PS1) associates with beta-catenin. In this study, we show that this interaction plays a critical role in regulating beta-catenin/T Cell Factor/Lymphoid Enhancer Factor-1 (LEF) signaling. PS1 deficiency results in accumulation of cytosolic beta-catenin, leading to a beta-catenin/LEF-dependent increase in cyclin D1 transcription and accelerated entry into the S phase of the cell cycle. Conversely, PS1 specifically represses LEF-dependent transcription in a dose-dependent manner. The hyperproliferative response can be reversed by reintroducing PS1 expression or overexpressing axin, but not a PS1 mutant that does not bind beta-catenin (PS1Deltacat) or by two different familial Alzheimer's disease mutants. In contrast, PS1Deltacat restores Notch-1 proteolytic cleavage and Abeta generation in PS1-deficient cells, indicating that PS1 function in modulating beta-catenin levels can be separated from its roles in facilitating gamma-secretase cleavage of beta-amyloid precursor protein and in Notch-1 signaling. Finally, we show an altered response to Wnt signaling and impaired ubiquitination of beta-catenin in the absence of PS1, a phenotype that may account for the increased stability in PS1-deficient cells. Thus, PS1 adds to the molecules that are known to regulate the rapid turnover of beta-catenin.
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Affiliation(s)
- Salvador Soriano
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093
| | - David E. Kang
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093
| | - Maofu Fu
- The Albert Einstein Cancer Center, Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Richard Pestell
- The Albert Einstein Cancer Center, Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Nathalie Chevallier
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093
| | - Hui Zheng
- Huffington Center on Aging and Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
| | - Edward H. Koo
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093
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