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Singh Y, Regmi D, Ormaza D, Ayyalasomayajula R, Vela N, Mundim G, Du D, Minond D, Cudic M. Mucin-Type O-Glycosylation Proximal to β-Secretase Cleavage Site Affects APP Processing and Aggregation Fate. Front Chem 2022; 10:859822. [PMID: 35464218 PMCID: PMC9023740 DOI: 10.3389/fchem.2022.859822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/07/2022] [Indexed: 12/04/2022] Open
Abstract
The amyloid-β precursor protein (APP) undergoes proteolysis by β- and γ-secretases to form amyloid-β peptides (Aβ), which is a hallmark of Alzheimer’s disease (AD). Recent findings suggest a possible role of O-glycosylation on APP’s proteolytic processing and subsequent fate for AD-related pathology. We have previously reported that Tyr681-O-glycosylation and the Swedish mutation accelerate cleavage of APP model glycopeptides by β-secretase (amyloidogenic pathway) more than α-secretase (non-amyloidogenic pathway). Therefore, to further our studies, we have synthesized additional native and Swedish-mutated (glyco)peptides with O-GalNAc moiety on Thr663 and/or Ser667 to explore the role of glycosylation on conformation, secretase activity, and aggregation kinetics of Aβ40. Our results show that conformation is strongly dependent on external conditions such as buffer ions and solvent polarity as well as internal modifications of (glyco)peptides such as length, O-glycosylation, and Swedish mutation. Furthermore, the level of β-secretase activity significantly increases for the glycopeptides containing the Swedish mutation compared to their nonglycosylated and native counterparts. Lastly, the glycopeptides impact the kinetics of Aβ40 aggregation by significantly increasing the lag phase and delaying aggregation onset, however, this effect is less pronounced for its Swedish-mutated counterparts. In conclusion, our results confirm that the Swedish mutation and/or O-glycosylation can render APP model glycopeptides more susceptible to cleavage by β-secretase. In addition, this study sheds new light on the possible role of glycosylation and/or glycan density on the rate of Aβ40 aggregation.
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Affiliation(s)
- YashoNandini Singh
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Deepika Regmi
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - David Ormaza
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Ramya Ayyalasomayajula
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Nancy Vela
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Gustavo Mundim
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Deguo Du
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Dmitriy Minond
- College of Pharmacy and Rumbaugh-Goodwin Institute for Cancer Research, Nova Southeastern University, Fort Lauderdale, FL, United States
| | - Maré Cudic
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
- *Correspondence: Maré Cudic,
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2
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Abstract
Peptidases generate bioactive peptides that can regulate cell signaling and mediate intercellular communication. While the processing of peptide precursors is initiated intracellularly, some modifications by peptidases may be conducted extracellularly. Thimet oligopeptidase (TOP) is a peptidase that processes neuroendocrine peptides with roles in mood, metabolism, and immune responses, among other functions. TOP also hydrolyzes angiotensin I to angiotensin 1–7, which may be involved in the pathophysiology of COVID-19 infection. Although TOP is primarily cytosolic, it can also be associated with the cell plasma membrane or secreted to the extracellular space. Recent work indicates that membrane-associated TOP can be released with extracellular vesicles (EVs) to the extracellular space. Here we briefly summarize the enzyme’s classical function in extracellular processing of neuroendocrine peptides, as well as its more recently understood role in intracellular processing of various peptides that impact human diseases. Finally, we discuss new findings of EV-associated TOP in the extracellular space.
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Pedrero-Prieto CM, Frontiñán-Rubio J, Alcaín FJ, Durán-Prado M, Peinado JR, Rabanal-Ruiz Y. Biological Significance of the Protein Changes Occurring in the Cerebrospinal Fluid of Alzheimer's Disease Patients: Getting Clues from Proteomic Studies. Diagnostics (Basel) 2021; 11:1655. [PMID: 34573996 PMCID: PMC8467255 DOI: 10.3390/diagnostics11091655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/18/2021] [Accepted: 08/26/2021] [Indexed: 11/16/2022] Open
Abstract
The fact that cerebrospinal fluid (CSF) deeply irrigates the brain together with the relative simplicity of sample extraction from patients make this biological fluid the best target for biomarker discovery in neurodegenerative diseases. During the last decade, biomarker discovery has been especially fruitful for the identification new proteins that appear in the CSF of Alzheimer's disease (AD) patients together with amyloid-β (Aβ42), total tau (T-tau), and phosphorylated tau (P-tau). Thus, several proteins have been already stablished as important biomarkers, due to an increase (i.e., CHI3L1) or a decrease (i.e., VGF) in AD patients' CSF. Notwithstanding this, only a deep analysis of a database generated with all the changes observed in CSF across multiple proteomic studies, and especially those using state-of-the-art methodologies, may expose those components or metabolic pathways disrupted at different levels in AD. Deep comparative analysis of all the up- and down-regulated proteins across these studies revealed that 66% of the most consistent protein changes in CSF correspond to intracellular proteins. Interestingly, processes such as those associated to glucose metabolism or RXR signaling appeared inversely represented in CSF from AD patients in a significant manner. Herein, we discuss whether certain cellular processes constitute accurate indicators of AD progression by examining CSF. Furthermore, we uncover new CSF AD markers, such as ITAM, PTPRZ or CXL16, identified by this study.
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Affiliation(s)
- Cristina M. Pedrero-Prieto
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, CRIB, University of Castilla-La Mancha (UCLM), Paseo de Moledores SN, 13071 Ciudad Real, Spain; (C.M.P.-P.); (J.F.-R.); (F.J.A.); (M.D.-P.)
- Neuroplasticity and Neurodegeneration Laboratory, Ciudad Real Medical School, CRIB, University of Castilla-La Mancha (UCLM), 13005 Ciudad Real, Spain
| | - Javier Frontiñán-Rubio
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, CRIB, University of Castilla-La Mancha (UCLM), Paseo de Moledores SN, 13071 Ciudad Real, Spain; (C.M.P.-P.); (J.F.-R.); (F.J.A.); (M.D.-P.)
| | - Francisco J. Alcaín
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, CRIB, University of Castilla-La Mancha (UCLM), Paseo de Moledores SN, 13071 Ciudad Real, Spain; (C.M.P.-P.); (J.F.-R.); (F.J.A.); (M.D.-P.)
| | - Mario Durán-Prado
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, CRIB, University of Castilla-La Mancha (UCLM), Paseo de Moledores SN, 13071 Ciudad Real, Spain; (C.M.P.-P.); (J.F.-R.); (F.J.A.); (M.D.-P.)
| | - Juan R. Peinado
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, CRIB, University of Castilla-La Mancha (UCLM), Paseo de Moledores SN, 13071 Ciudad Real, Spain; (C.M.P.-P.); (J.F.-R.); (F.J.A.); (M.D.-P.)
| | - Yoana Rabanal-Ruiz
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, CRIB, University of Castilla-La Mancha (UCLM), Paseo de Moledores SN, 13071 Ciudad Real, Spain; (C.M.P.-P.); (J.F.-R.); (F.J.A.); (M.D.-P.)
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4
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Singh Y, Ormaza D, Massetti A, Minond D, Cudic M. Tyrosine O-GalNAc Alters the Conformation and Proteolytic Susceptibility of APP Model Glycopeptides. ACS Chem Neurosci 2021; 12:2974-2980. [PMID: 34324289 PMCID: PMC8378340 DOI: 10.1021/acschemneuro.1c00387] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
![]()
The amyloid-β precursor protein (APP) undergoes proteolytic cleavage by α-,
β-, and γ-secretases, to determine its fate in Alzheimer’s disease
(AD) pathogenesis. Recent findings suggest a possible role of
O-glycosylation in APP’s proteolytic processing. Therefore, we
synthesized native and Swedish-double-mutated APP (glyco)peptides with
Tyr681-O-GalNAc. We studied conformational changes and
proteolytic processing using circular dichroism (CD) spectroscopy and enzyme cleavage
assay, respectively. CD analysis was carried out in four solvent systems to evaluate
peptide environment and O-glycosylation induced conformational changes.
The Swedish mutation and Tyr681-O-GalNAc were the key
factors driving conformational changes. Furthermore, the level of α- and
β-secretase activity was increased by the presence of mutation and this effect was
more pronounced for its glycosylated analogues. Our results suggest that
O-glycosylation of Tyr681 can induce a conformational
change in APP and affect its proteolytic processing fate toward the amyloidogenic
pathway.
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Affiliation(s)
- YashoNandini Singh
- Department of Chemistry and Biochemistry, Charles E, Schmidt College of Science, Florida Atlantic University, 777 Glades Road, Boca Raton, Florida 33431, United States
| | - David Ormaza
- Department of Chemistry and Biochemistry, Charles E, Schmidt College of Science, Florida Atlantic University, 777 Glades Road, Boca Raton, Florida 33431, United States
| | - Alessandra Massetti
- Department of Chemistry and Biochemistry, Charles E, Schmidt College of Science, Florida Atlantic University, 777 Glades Road, Boca Raton, Florida 33431, United States
| | - Dmitriy Minond
- College of Pharmacy and Rumbaugh-Goodwin Institute for Cancer Research, Nova Southeastern University, 3301 College Ave, Fort Lauderdale, Florida 33314, United States
| | - Maré Cudic
- Department of Chemistry and Biochemistry, Charles E, Schmidt College of Science, Florida Atlantic University, 777 Glades Road, Boca Raton, Florida 33431, United States
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5
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Huang YR, Liu RT. The Toxicity and Polymorphism of β-Amyloid Oligomers. Int J Mol Sci 2020; 21:E4477. [PMID: 32599696 PMCID: PMC7352971 DOI: 10.3390/ijms21124477] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/19/2020] [Accepted: 06/20/2020] [Indexed: 12/26/2022] Open
Abstract
It is widely accepted that β-amyloid oligomers (Aβos) play a key role in the progression of Alzheimer's disease (AD) by inducing neuron damage and cognitive impairment, but Aβos are highly heterogeneous in their size, structure and cytotoxicity, making the corresponding studies tough to carry out. Nevertheless, a number of studies have recently made remarkable progress in the describing the characteristics and pathogenicity of Aβos. We here review the mechanisms by which Aβos exert their neuropathogenesis for AD progression, including receptor binding, cell membrane destruction, mitochondrial damage, Ca2+ homeostasis dysregulation and tau pathological induction. We also summarize the characteristics and pathogenicity such as the size, morphology and cytotoxicity of dimers, trimers, Aβ*56 and spherical oligomers, and suggest that Aβos may play a different role at different phases of AD pathogenesis, resulting in differential consequences on neuronal synaptotoxicity and survival. It is warranted to investigate the temporal sequence of Aβos in AD human brain and examine the relationship between different Aβos and cognitive impairment.
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Affiliation(s)
- Ya-ru Huang
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
- School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rui-tian Liu
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
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Chen S, Ge X, Chen Y, Lv N, Liu Z, Yuan W. Advances with RNA interference in Alzheimer's disease research. DRUG DESIGN DEVELOPMENT AND THERAPY 2013; 7:117-25. [PMID: 23459401 PMCID: PMC3582316 DOI: 10.2147/dddt.s40229] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized clinically by memory and cognitive dysfunction. Unfortunately, there is no effective therapeutic method for AD treatment or ways to halt disease progression. Many mechanisms are involved in the disease, including genes mutation and protein dysfunction. RNA interference (RNAi) technology may potentially be able to control AD. It can inhibit the protein expression of specific genes by activating a sequence-specific RNA degradation process. This is a powerful tool with which to study gene function, investigate the mechanism of the disease, and validate drug targets. In this review, we highlight the advances in RNAi technology in the investigation and treatment of AD.
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Affiliation(s)
- Shun Chen
- Department of Neurology, Xinhua Hospital affiliated to Shanghai Jiaotong University School of Medicine, Shanghai Jiaotong University, Shanghai
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7
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The Enigma of Tripeptidyl-Peptidase II: Dual Roles in Housekeeping and Stress. JOURNAL OF ONCOLOGY 2010; 2010. [PMID: 20847939 PMCID: PMC2933905 DOI: 10.1155/2010/128478] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 05/25/2010] [Accepted: 07/12/2010] [Indexed: 12/02/2022]
Abstract
The tripeptidyl-peptidase II complex consists of repeated 138 kDa subunits, assembled into two twisted strands that form a high molecular weight complex (>5 MDa). TPPII, like many other cytosolic peptidases, plays a role in the ubiquitin-proteasome pathway downstream of the proteasome as well as in the production and destruction of MHC class I antigens and degradation of neuropeptides. Tripeptidyl-peptidase II activity is increased in cells with an increased demand for protein degradation, but whether degradation of cytosolic peptides is the only cell biological role for TPPII has remained unclear. Recent data indicated that TPPII translocates into the nucleus to control DNA damage responses in malignant cells, supporting that cytosolic “housekeeping peptidases” may have additional roles in cell biology, besides their contribution to protein turnover. Overall, TPPII has an emerging importance in several cancer-related fields, such as metabolism, cell death control, and control of genome integrity; roles that are not understood in detail. The present paper reviews the cell biology of TPPII and discusses distinct roles for TPPII in the nucleus and cytosol.
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8
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Mancini F, Andrisano V. Development of a liquid chromatographic system with fluorescent detection for β-secretase immobilized enzyme reactor on-line enzymatic studies. J Pharm Biomed Anal 2010; 52:355-61. [DOI: 10.1016/j.jpba.2009.07.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 07/04/2009] [Accepted: 07/09/2009] [Indexed: 11/24/2022]
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9
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Kakizawa T, Hidaka K, Hamada D, Yamaguchi R, Uemura T, Kitamura H, Tagad HD, Hamada T, Ziora Z, Hamada Y, Kimura T, Kiso Y. Tetrapeptides, as small-sized peptidic inhibitors; synthesis and their inhibitory activity against BACE1. J Pept Sci 2010; 16:257-62. [DOI: 10.1002/psc.1238] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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10
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Sigman J, Patwa T, Tablante A, Joseph C, Glucksman M, Wolfson A. Flexibility in substrate recognition by thimet oligopeptidase as revealed by denaturation studies. Biochem J 2009; 388:255-61. [PMID: 15647004 PMCID: PMC1186714 DOI: 10.1042/bj20041481] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Thimet oligopeptidase (TOP) is a soluble metalloendopeptidase belonging to a family of enzymes including neurolysin and neprilysin that utilize the HEXXH metal-binding motif. TOP is widely distributed among cell types and is able to cleave a number of structurally unrelated peptides. A recent focus of interest has been on structure-function relationships in substrate selectivity by TOP. The enzyme's structural fold comprises two domains that are linked at the bottom of a deep substrate-binding cleft via several flexible loop structures. In the present study, fluorescence spectroscopy has been used to probe structural changes in TOP induced by the chemical denaturant urea. Fluorescence emission, anisotropy and collisional quenching data support a two-step unfolding process for the enzyme in which complete loss of the tertiary structure occurs in the second step. Complete loss of activity and loss of catalytic Zn(II) from the active site, monitored by absorption changes of the metal chelator 4-(2-pyridylazo)-resorcinol, are also connected with the second step. In contrast, the first unfolding event, which is linked to changes in the non-catalytic domain, leads to a sharp increase in kcat towards a 9-residue substrate and a sharp decrease in kcat for a 5-residue substrate. Thus a conformational change in TOP has been directly correlated with a change in substrate selectivity. These results provide insight into how the enzyme can process the range of structurally unrelated peptides necessary for its many physiological roles.
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Affiliation(s)
- Jeffrey A. Sigman
- *Chemistry Department, Saint Mary's College of California, 1928 St. Mary's Road, Moraga, CA 94556, U.S.A
| | - Tasneem H. Patwa
- †Chemistry Department, Wellesley College, 106 Central Street, Wellesley, MA 02841, U.S.A
| | - Ana V. Tablante
- †Chemistry Department, Wellesley College, 106 Central Street, Wellesley, MA 02841, U.S.A
| | - Calleen D. Joseph
- †Chemistry Department, Wellesley College, 106 Central Street, Wellesley, MA 02841, U.S.A
| | - Marc J. Glucksman
- ‡Midwest Proteome Center and Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, N. Chicago, IL 60064, U.S.A
| | - Adele J. Wolfson
- †Chemistry Department, Wellesley College, 106 Central Street, Wellesley, MA 02841, U.S.A
- To whom correspondence should be addressed (email )
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11
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Koike H, Kouchi Z, Kinouchi T, Maeda T, Sorimachi H, Saido TC, Maruyama K, Okuyama A, Suzuki K, Ishiura S. Metabolism of amyloid precursor protein in COS cells transfected with a beta-secretase candidate. Cytotechnology 2008; 33:213-9. [PMID: 19002828 DOI: 10.1023/a:1008119512341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Thimet oligopeptidase (TOP) is a thiol- andmetallo-dependent peptidase and has been shown to beone of the beta-secretase candidates. TOPexpressed in COS cells cleaved amyloid precursorprotein (APP) at the beta-secretase site, and wefound a proteolytic product of APP called secretedform of APP by beta-secretase (sAPPbeta) in theconditioned media. Here we demonstrate thatsAPPbeta was increased in conditioned media whenTOP was coexpressed in COS cells with APP and treatedwith an ADAM inhibitor SI-27. In addition, althoughTOP expressed in COS cell was localized at nuclei orGolgi apparatus, it exclusively colocalized at Golgiapparatus when APP was coexpressed with TOP.
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Affiliation(s)
- H Koike
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902, Japan
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12
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Pollio G, Hoozemans JJM, Andersen CA, Roncarati R, Rosi MC, van Haastert ES, Seredenina T, Diamanti D, Gotta S, Fiorentini A, Magnoni L, Raggiaschi R, Rozemuller AJM, Casamenti F, Caricasole A, Terstappen GC. Increased expression of the oligopeptidase THOP1 is a neuroprotective response to Abeta toxicity. Neurobiol Dis 2008; 31:145-58. [PMID: 18571100 DOI: 10.1016/j.nbd.2008.04.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 04/03/2008] [Accepted: 04/17/2008] [Indexed: 01/18/2023] Open
Abstract
In a comprehensive proteomics study aiming at the identification of proteins associated with amyloid-beta (Abeta)-mediated toxicity in cultured cortical neurons, we have identified Thimet oligopeptidase (THOP1). Functional modulation of THOP1 levels in primary cortical neurons demonstrated that its overexpression was neuroprotective against Abeta toxicity, while RNAi knockdown made neurons more vulnerable to amyloid peptide. In the TgCRND8 transgenic mouse model of amyloid plaque deposition, an age-dependent increase of THOP1 expression was found in brain tissue, where it co-localized with Abeta plaques. In accordance with these findings, THOP1 expression was significantly increased in human AD brain tissue as compared to non-demented controls. These results provide compelling evidence for a neuroprotective role of THOP1 against toxic effects of Abeta in the early stages of AD pathology, and suggest that the observed increase in THOP1 expression might be part of a compensatory defense mechanism of the brain against an increased Abeta load.
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Affiliation(s)
- Giuseppe Pollio
- Siena Biotech SpA, Discovery Research, Via Fiorentina 1, 53100 Siena, Italy
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13
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Heiseke A, Schöbel S, Lichtenthaler SF, Vorberg I, Groschup MH, Kretzschmar H, Schätzl HM, Nunziante M. The novel sorting nexin SNX33 interferes with cellular PrP formation by modulation of PrP shedding. Traffic 2008; 9:1116-29. [PMID: 18419754 DOI: 10.1111/j.1600-0854.2008.00750.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The cellular prion protein (PrP(c)) is a glycosyl-phosphatidylinositol (GPI)-anchored protein trafficking in the secretory and endocytic pathway and localized mainly at the plasma membrane. Conversion of PrP(c) into its pathogenic isoform PrP(Sc) is associated with pathogenesis and transmission of prion diseases. Intramolecular cleavage in the middle, the extreme C-terminal part or within the GPI anchor and shedding of PrP(c) modulate this conversion process by reducing the substrate for prion formation. These phenomena provide similarities with the processing of amyloid precursor protein in Alzheimer's disease. Sorting nexins are a family of proteins with important functions in protein trafficking. In this study, we investigated the role of the newly described sorting nexin 33 (SNX33) in trafficking and processing of PrP(c). We found that overexpression of SNX33 in neuronal and non-neuronal cell lines resulted in increased shedding of full-length PrP(c) from the plasma membrane and modulated the rate of PrP(c) endocytosis. This was paralleled by reduction of PrP(Sc) formation in persistently and newly infected cells. Using deletion mutants, we demonstrate that production of PrP fragment N1 is not influenced by SNX33. Our data provide new insights into the cellular mechanisms of PrP(c) shedding and show how this can affect cellular PrP(Sc) conversion.
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Affiliation(s)
- Andreas Heiseke
- Institute of Virology, Technical University of Munich, Trogerstr. 30, 81675 Munich, Germany
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14
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Ray K, Hines CS, Coll-Rodriguez J, Rodgers DW. Crystal structure of human thimet oligopeptidase provides insight into substrate recognition, regulation, and localization. J Biol Chem 2004; 279:20480-9. [PMID: 14998993 DOI: 10.1074/jbc.m400795200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thimet oligopeptidase (TOP) is a zinc metallopeptidase that metabolizes a number of bioactive peptides and degrades peptides released by the proteasome, limiting antigenic presentation by MHC class I molecules. We present the crystal structure of human TOP at 2.0-A resolution. The active site is located at the base of a deep channel that runs the length of the elongated molecule, an overall fold first seen in the closely related metallopeptidase neurolysin. Comparison of the two related structures indicates hinge-like flexibility and identifies elements near one end of the channel that adopt different conformations. Relatively few of the sequence differences between TOP and neurolysin map to the proposed substrate-binding site, and four of these variable residues may account for differences in substrate specificity. In addition, a loop segment (residues 599-611) in TOP differs in conformation and degree of order from the corresponding neurolysin loop, suggesting it may also play a role in activity differences. Cysteines thought to mediate covalent oligomerization of rat TOP, which can inactivate the enzyme, are found to be surface-accessible in the human enzyme, and additional cysteines (residues 321,350, and 644) may also mediate multimerization in the human homolog. Disorder in the N terminus of TOP indicates it may be involved in subcellular localization, but a potential nuclear import element is found to be part of a helix and, therefore, unlikely to be involved in transport. A large acidic patch on the surface could potentially mediate a protein-protein interaction, possibly through formation of a covalent linkage.
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Affiliation(s)
- Kallol Ray
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, KY 40536, USA
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15
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Komai T, Kawabata C, Amano M, Lee BR, Ichishima E. Todarepsin, a new cathepsin D from hepatopancreas of Japanese common squid (Todarodes pacificus). Comp Biochem Physiol B Biochem Mol Biol 2004; 137:373-82. [PMID: 15050524 DOI: 10.1016/j.cbpc.2004.01.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2003] [Revised: 12/28/2003] [Accepted: 01/05/2004] [Indexed: 11/20/2022]
Abstract
An intracellular aspartic proteinase obtained from the hepatopancreas (liver) of Japanese common squid (Todarodes pacificus) was purified to homogeneity. The molecular mass of the enzyme was 36,500 Da on SDS-PAGE, and the isoelectric point was 8.29 by isoelectric focusing. The enzyme activity was optimal at pH 3.5, pH 2.2 and pH 3.0 for the substrates acid-denatured hemoglobin, acid-denatured casein, and MOCAc-GKPILFFRLK(Dnp)-D-R-NH2, respectively. Enzyme activity decreased rapidly at 50 degrees C. The Km and kcat values of the enzyme were estimated to be 3.2 mM and 46 s(-1) with MOCAc-GKPILFFRLK(Dnp)-D-R-NH2, and 1.7 mM and 1.1 s(-1) with MOCAc-SEVNLDAEFRK(Dnp)RR-NH2. The enzyme activity was strongly inhibited by pepstatin A, but only partially inhibited by DAN and EPNP. The Ki values for pepstatin A, DAN and EPNP were 0.5 nM, 0.5 mM and 0.2 mM, respectively. A cDNA encoding the enzyme was cloned by RT-PCR and subjected to nucleotide sequencing. The entire open reading frame was 1179 bp and coded for a protein of 392 amino acid residues. The mature enzyme consisted of 334 amino acids. The deduced amino acid sequence of the enzyme showed a high degree of identity to the sequences of cathepsins D found in various species.
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Affiliation(s)
- Tsuyoshi Komai
- Technical Research Center, T. Hasegawa Co., Ltd., Kariyado, 335 Nakahara-ku, Kawasaki 211-0022, Japan.
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Kim SI, Grum-Tokars V, Swanson TA, Cotter EJ, Cahill PA, Roberts JL, Cummins PM, Glucksman MJ. Novel roles of neuropeptide processing enzymes: EC3.4.24.15 in the neurome. J Neurosci Res 2003; 74:456-67. [PMID: 14598322 DOI: 10.1002/jnr.10779] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Neuropeptide processing metalloenzymes, such as angiotensin converting enzyme, neprilysin, endothelin converting enzyme, neurolysin, and EC3.4.24.15 (EP24.15), are central to the formation and degradation of bioactive peptides. We present EP24.15 as a paradigm for novel functions ascribed to these enzymes in the neurome. Although the neurome typically encompasses proteomes of the brain and central nervous system, exciting new roles of these neuropeptidases have been demonstrated in other organ systems. We discuss the involvement of EP24.15 with clinical sequelae involving the use of gonadotropin-releasing hormone (GnRH; LHRH) analogs that act as enzyme inhibitors, in vascular physiology (blood pressure regulation), and in the hematologic system (immune surveillance). Hemodynamic forces, such as cyclic strain and shear stress, on vascular cells, induce an increase in EP24.15 transcription, suggesting that neuropeptidase-mediated hydrolysis of pressor/depressor peptides is likely regulated by changes in hemodynamic force and blood pressure. Lastly, EP24.15 regulates surface expression of major histocompatibility complex Class I proteins in vivo, suggesting that EP24.15 may play an important role in maintenance of immune privilege in sites of increased endogenous expression. In these extraneural systems, regulation of both neuropeptide and other peptide substrates by neuropeptidases indicates that the influence of these enzymes may be more global than was anticipated previously, and suggests that their attributed role as neuropeptidases underestimates their physiologic actions in the neural system.
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Affiliation(s)
- S I Kim
- Midwest Proteome Center, Department of Biochemistry and Molecular Biology, Finch University of Health Sciences/Chicago Medical School, North Chicago, Illinois 60064, USA
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17
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Shuto D, Kasai S, Kimura T, Liu P, Hidaka K, Hamada T, Shibakawa S, Hayashi Y, Hattori C, Szabo B, Ishiura S, Kiso Y. KMI-008, a novel β-Secretase inhibitor containing a hydroxymethylcarbonyl isostere as a transition-State mimic: design and synthesis of substrate-based octapeptides. Bioorg Med Chem Lett 2003; 13:4273-6. [PMID: 14643307 DOI: 10.1016/j.bmcl.2003.09.053] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
A novel class of substrate-based beta-secretase (BACE1) inhibitors containing a hydroxymethylcarbonyl (HMC) isostere was designed and synthesized. Phenylnorstatine [(2R,3S)-3-amino-2-hydroxy-4-phenylbutyric acid; Pns] was an effective transition-state mimic at the P(1) position. Structure-activity relationships (SARs) of the P(3)-P(3)' positions of BACE1 inhibitors were studied.
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Affiliation(s)
- Daisuke Shuto
- Department of Medicinal Chemistry, Center for Frontier Research in Medicinal Science, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan
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18
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Ahmed MM, Yamamoto M, Chikuma T, Rahman MK, Kato T. Dose-dependent effect of MK-801 on the levels of neuropeptides processing enzymes in rat brain regions. Neurosci Res 2003; 47:177-89. [PMID: 14512142 DOI: 10.1016/s0168-0102(03)00197-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The appropriate levels of neuropeptides and their processing enzyme activities are required to continue a normal cell life, and the dysfunction of these peptides and enzymes are responsible for many neuronal abnormalities. Systemic administration of (+) MK-801 (dizocilpine maleate), a noncompetitive N-methyl-[D]-aspartate (NMDA) receptor antagonist, causes both neuroprotective and neurotoxic activities depending on doses and conditions. In the present study, we investigated the dose dependent effect of (+) MK-801 on prolyl endopeptidase (PEP), endopeptidase EC 24.15 (EP 24.15) and beta-D-glucuronidase activities as well as the protein levels of EP 24.15 and neuron specific enolase (NSE) in the posterior cingulate/retrosplenial cortices (PC/RSC), hippocampus, frontal cortex and striatum of female rats 3 days after the treatment. The activity of PEP was significantly increased compared with controls (saline) in the PC/RSC at 1.0 and 5.0 mg/kg doses, and in the frontal cortex at 5.0 mg/kg dose. beta-D-Glucuronidase activity was dose-dependently increased in all brain regions examined. The activity of EP 24.15 was unchanged in all regions after the treatment, whereas the Western blot analysis for EP 24.15 showed the increased protein level in the PC/RSC. These results suggest that a low dose treatment with MK-801 causes neurotoxicity in the PC/RSC and hippocampus, and the high dose treatment causes neurotoxicity in all the brain regions examined.
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Affiliation(s)
- Md Mahiuddin Ahmed
- Laboratory of Natural Information Science, Graduate School of Integrated Science, Yokohama City University, 22-2 Seto, Kanazawa-Ku, Yokohama 236-0027, Japan
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19
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Kim SI, Pabon A, Swanson TA, Glucksman MJ. Regulation of cell-surface major histocompatibility complex class I expression by the endopeptidase EC3.4.24.15 (thimet oligopeptidase). Biochem J 2003; 375:111-20. [PMID: 12877658 PMCID: PMC1223673 DOI: 10.1042/bj20030490] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2003] [Revised: 07/23/2003] [Accepted: 07/24/2003] [Indexed: 11/17/2022]
Abstract
Endopeptidase EP24.15 (EC 3.4.24.15; thimet oligopeptidase), traditionally classified as a neuropeptide-processing enzyme, degrades well-known MHC I (major histocompatibility complex class I) peptides in cell extracts. In the present study, we determine the contribution of EP24.15 in vivo to the surface expression of MHC I on intact cells. CTLs (cytotoxic T-lymphocytes) recognize a vast array of peptides presented in the context of MHC I cell-surface molecules. Stable retroviral overexpression of EP24.15 induces a dramatic, long-term inhibition of surface MHC I. In contrast, overexpression of a mutant EP24.15, which is expressed, but is enzymically inactive, does not affect the surface MHC I expression level. We observed no difference in the effect of EP24.15 on the expression of different classes of MHC I. IFN-gamma (interferon-gamma) treatment re-established MHC I expression on these EP24.15-overexpressing cells, and also induced EP24.15 cytosolic protein expression and enzyme activity. To our knowledge, this is the first demonstration of cytokine-induced EP24.15 expression and activity. Conversely, stable retroviral silencing of endogenous EP24.15 by RNA interference induced a striking, long-term increase in surface MHC I. Subcellular fractionation and enzyme-activity experiments localized the vast majority of EP24.15 protein expression and function to the cytosol. Therefore we introduce a novel function of the cytosolic form of EP24.15. EP24.15 activity in the extracellular space is significant for neuropeptide processing, and in the present paper, we demonstrate that EP24.15 activity in the cytosol may be significant for regulation of MHC I cell-surface expression.
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Affiliation(s)
- Sandra I Kim
- Midwest Proteome Center, Department of Biochemistry and Molecular Biology, Finch University of Health Sciences/Chicago Medical School, 3333 Green Bay Road, North Chicago, IL 60064, USA
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20
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Abstract
Peptidases play a vital and often highly specific role in the physiological and pathological generation and termination of peptide hormone signals. The thermolysin-like family of metalloendopeptidases involved in the extracellular processing of neuroendocrine and cardiovascular peptides are of particular significance, reflecting both their specificity for particular peptide substrates and their utility as therapeutic targets. Although the functions of the membrane-bound members of this family, such as angiotensin-converting enzyme and neutral endopeptidase, are well established, a role for the predominantly soluble family members in peptide metabolism is only just emerging. This review will focus on the biochemistry, cell biology, and physiology of the soluble metalloendopeptidases EC 3.4.24.15 (thimet oligopeptidase) and EC 3.4.24.16 (neurolysin), as well as presenting evidence that both peptidases play an important role in such diverse functions as reproduction, nociception, and cardiovascular homeostasis.
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21
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Shaw KT, Utsuki T, Rogers J, Yu QS, Sambamurti K, Brossi A, Ge YW, Lahiri DK, Greig NH. Phenserine regulates translation of beta -amyloid precursor protein mRNA by a putative interleukin-1 responsive element, a target for drug development. Proc Natl Acad Sci U S A 2001; 98:7605-10. [PMID: 11404470 PMCID: PMC34715 DOI: 10.1073/pnas.131152998] [Citation(s) in RCA: 146] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2000] [Accepted: 03/29/2001] [Indexed: 01/21/2023] Open
Abstract
The reduction in levels of the potentially toxic amyloid-beta peptide (Abeta) has emerged as one of the most important therapeutic goals in Alzheimer's disease. Key targets for this goal are factors that affect the expression and processing of the Abeta precursor protein (betaAPP). Earlier reports from our laboratory have shown that a novel cholinesterase inhibitor, phenserine, reduces betaAPP levels in vivo. Herein, we studied the mechanism of phenserine's actions to define the regulatory elements in betaAPP processing. Phenserine treatment resulted in decreased secretion of soluble betaAPP and Abeta into the conditioned media of human neuroblastoma cells without cellular toxicity. The regulation of betaAPP protein expression by phenserine was posttranscriptional as it suppressed betaAPP protein expression without altering betaAPP mRNA levels. However, phenserine's action was neither mediated through classical receptor signaling pathways, involving extracellular signal-regulated kinase or phosphatidylinositol 3-kinase activation, nor was it associated with the anticholinesterase activity of the drug. Furthermore, phenserine reduced expression of a chloramphenicol acetyltransferase reporter fused to the 5'-mRNA leader sequence of betaAPP without altering expression of a control chloramphenicol acetyltransferase reporter. These studies suggest that phenserine reduces Abeta levels by regulating betaAPP translation via the recently described iron regulatory element in the 5'-untranslated region of betaAPP mRNA, which has been shown previously to be up-regulated in the presence of interleukin-1. This study identifies an approach for the regulation of betaAPP expression that can result in a substantial reduction in the level of Abeta.
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Affiliation(s)
- K T Shaw
- Drug Design and Development, Laboratory of Neurosciences, National Institute on Aging, Baltimore, MD 21224, USA
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22
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Abstract
The extracellular deposition of short amyloid peptides in the brain of patients is thought to be a central event in the pathogenesis of Alzheimer's Disease. The generation of the amyloid peptide occurs via a regulated cascade of cleavage events in its precursor protein, A beta PP. At least three enzymes are responsible for A beta PP proteolysis and have been tentatively named alpha-, beta- and gamma-secretases. The recent identification of several of these secretases is a major leap in the understanding how these secretases regulate amyloid peptide formation. Members of the ADAM family of metalloproteases are involved in the non-amyloidogenic alpha-secretase pathway. The amyloidogenic counterpart pathway is initiated by the recently cloned novel aspartate protease named BACE. The available data are conclusive and crown BACE as the long-sought beta-secretase. This enzyme is a prime candidate drug target for the development of therapy aiming to lower the amyloid burden in the disease. Finally, the gamma-secretases are intimately linked to the function of the presenilins. These multi-transmembrane domain proteins remain intriguing study objects. The hypothesis that the presenilins constitute a complete novel type of protease family, and are cleaving A beta PP within the transmembrane region, remains an issue of debate. Several questions remain unanswered and direct proof that they exert catalytic activity is still lacking. The subcellular localization of presenilins in neurons, their integration in functional multiprotein complexes and the recent identification of additional modulators of gamma-secretase, like nicastrin, indicate already that several players are involved. Nevertheless, the rapidly increasing knowledge in this area is already paving the road towards selective inhibitors of this secretase as well. It is hoped that such drugs, possibly in concert with the experimental vaccination therapies that are currently tested, will lead to a cure of this inexorable disease.
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Affiliation(s)
- D I Dominguez
- Flanders Interuniversitary Institute for Biotechnology and K.U. Leuven, Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Gasthuisberg, B-3000 Leuven, Belgium
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23
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Futai E, Kubo T, Sorimachi H, Suzuki K, Maeda T. Molecular cloning of PalBH, a mammalian homologue of the Aspergillus atypical calpain PalB. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1517:316-9. [PMID: 11342116 DOI: 10.1016/s0167-4781(00)00256-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A mammalian homologue of the Aspergillus atypical calpain PalB, PalBH, was identified and its cDNA sequences were determined in human and mouse. The PalBH mRNA was expressed nearly ubiquitously throughout mammalian tissues. When expressed in COS cells, PalBH was enriched in the nucleus, suggesting its role is distinct from that of conventional calpains.
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Affiliation(s)
- E Futai
- Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
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24
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Pinnix I, Musunuru U, Tun H, Sridharan A, Golde T, Eckman C, Ziani-Cherif C, Onstead L, Sambamurti K. A novel gamma -secretase assay based on detection of the putative C-terminal fragment-gamma of amyloid beta protein precursor. J Biol Chem 2001; 276:481-7. [PMID: 11035007 DOI: 10.1074/jbc.m005968200] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Alzheimer's disease is characterized by the deposits of the 4-kDa amyloid beta peptide (A beta). The A beta protein precursor (APP) is cleaved by beta-secretase to generate a C-terminal fragment, CTF beta, which in turn is cleaved by gamma-secretase to generate A beta. Alternative cleavage of the APP by alpha-secretase at A beta 16/17 generates the C-terminal fragment, CTFalpha. In addition to A beta, endoproteolytic cleavage of CTF alpha and CTF beta by gamma-secretase should yield a C-terminal fragment of 57-59 residues (CTF gamma). However, CTF gamma has not yet been reported in either brain or cell lysates, presumably due to its instability in vivo. We detected the in vitro generation of A beta as well as an approximately 6-kDa fragment from guinea pig brain membranes. We have provided biochemical and pharmacological evidence that this 6-kDa fragment is the elusive CTF gamma, and we describe an in vitro assay for gamma-secretase activity. The fragment migrates with a synthetic peptide corresponding to the 57-residue CTF gamma fragment. Three compounds previously identified as gamma-secretase inhibitors, pepstatin-A, MG132, and a substrate-based difluoroketone (t-butoxycarbonyl-Val-Ile-(S)-4-amino-3-oxo-2, 2-difluoropentanoyl-Val-Ile-OMe), reduced the yield of CTF gamma, providing additional evidence that the fragment arises from gamma-secretase cleavage. Consistent with reports that presenilins are the elusive gamma-secretases, subcellular fractionation studies showed that presenilin-1, CTF alpha, and CTF beta are enriched in the CTF gamma-generating fractions. The in vitro gamma-secretase assay described here will be useful for the detailed characterization of the enzyme and to screen for gamma-secretase inhibitors.
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Affiliation(s)
- I Pinnix
- Mayo Clinic, Jacksonville, Florida 32224, USA
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25
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Okida N, Tokumoto M, Tokumoto T, Nagahama Y, Ohe Y, Miyamoto K, Ishikawa K. Cloning of cDNA Encoding Thimet Oligopeptidase from Xenopus Oocytes and Regulation of the mRNA During Oogenesis. Zoolog Sci 2000. [DOI: 10.2108/0289-0003(2000)17[431:coceto]2.0.co;2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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