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González C, Martínez‐Sánchez L, Clemente P, Toivonen JM, Arredondo JJ, Fernández‐Moreno MÁ, Carrodeguas JA. Dysfunction of Drosophila mitochondrial carrier homolog (Mtch) alters apoptosis and disturbs development. FEBS Open Bio 2024; 14:276-289. [PMID: 38013241 PMCID: PMC10839352 DOI: 10.1002/2211-5463.13742] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/27/2023] [Accepted: 11/24/2023] [Indexed: 11/29/2023] Open
Abstract
Mitochondrial carrier homologs 1 (MTCH1) and 2 (MTCH2) are orphan members of the mitochondrial transporter family SLC25. Human MTCH1 is also known as presenilin 1-associated protein, PSAP. MTCH2 is a receptor for tBid and is related to lipid metabolism. Both proteins have been recently described as protein insertases of the outer mitochondrial membrane. We have depleted Mtch in Drosophila and show here that mutant flies are unable to complete development, showing an excess of apoptosis during pupation; this observation was confirmed by RNAi in Schneider cells. These findings are contrary to what has been described in humans. We discuss the implications in view of recent reports concerning the function of these proteins.
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Affiliation(s)
- Cristina González
- Departamento de Bioquímica & Instituto de Investigaciones Biomédicas “Alberto Sols”The Autonomous University of Madrid‐Consejo Superior de Investigaciones CientíficasSpain
| | - Lidia Martínez‐Sánchez
- Departamento de Bioquímica & Instituto de Investigaciones Biomédicas “Alberto Sols”The Autonomous University of Madrid‐Consejo Superior de Investigaciones CientíficasSpain
| | - Paula Clemente
- Departamento de Bioquímica & Instituto de Investigaciones Biomédicas “Alberto Sols”The Autonomous University of Madrid‐Consejo Superior de Investigaciones CientíficasSpain
| | - Janne Markus Toivonen
- LAGENBIO, Departamento de Anatomía, Embriología y Genética Animal, Facultad de Veterinaria, Instituto Agroalimentario de Aragón (IA2)Universidad de ZaragozaSpain
- IIS AragónZaragozaSpain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED)MadridSpain
| | - Juan José Arredondo
- Departamento de Bioquímica & Instituto de Investigaciones Biomédicas “Alberto Sols”The Autonomous University of Madrid‐Consejo Superior de Investigaciones CientíficasSpain
| | - Miguel Ángel Fernández‐Moreno
- Centro de Investigación Biomédica en Red en Enfermedades Raras (CIBERER)Facultad de Medicina, UAMMadridSpain
- Departamento de Bioquímica & Instituto de Investigaciones Biomédicas Sols‐MorrealeThe Autonomous University of Madrid‐Consejo Superior de Investigaciones CientíficasMadridSpain
| | - José Alberto Carrodeguas
- IIS AragónZaragozaSpain
- Institute for Biocomputation and Physics of Complex Systems (BIFI)University of ZaragozaSpain
- Department of Biochemistry and Molecular and Cellular Biology, School of SciencesUniversity of ZaragozaSpain
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Zhang J, Zhao ZJ, Fu X, Niu H, Hu C, Dong Y, Cui MZ, Zhang F, Zeng L, Xu X. Proapoptotic Mitochondrial Carrier Homolog Protein PSAP Mediates Death Receptor 6 Induced Apoptosis. J Alzheimers Dis 2021; 74:1097-1106. [PMID: 32144986 DOI: 10.3233/jad-191086] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Presenilin-associated protein (PSAP) was originally identified as a mitochondrial proapoptotic protein. To further explore the apoptotic pathway that involves PSAP, our yeast two-hybrid screen revealed that PSAP interacts with a death receptor, DR6. DR6 is a relatively less common member of the death receptor family and has been shown to mediate the neurotoxicity of amyloid-β, mutant SOD1, and prion proteins and has also been implicated in the regulation of immune cell proliferation and differentiation. Our previous study showed that DR6 induces apoptosis via a unique mitochondria-dependent pathway different from the conventional death receptor-mediated extrinsic apoptotic pathways. Thus, the interaction of DR6 with PSAP established a direct molecular link between DR6 and mitochondrial apoptotic pathway. We investigated the possible role of PSAP in DR6-induced apoptosis. Interestingly, it was discovered that knockdown of PSAP strongly inhibited DR6-induced apoptosis. To further elucidate the mechanism by which PSAP mediates DR6-induced mitochondria-dependent apoptosis, our data demonstrated that knockdown of PSAP blocked DR6-induced Bax translocation and cytochrome c release from the mitochondria. Moreover, it was found that both PSAP and DR6 form complexes with Bax, but at different subcellular locations. The DR6-Bax complex was detected in the cytosolic fraction while the PSAP-Bax complex was detected in the mitochondrial fraction. The observation that knockdown of DR6 significantly reduced the amount of PSAP-Bax complex detected in mitochondria suggests a possibility that DR6-bound Bax is transferred to PSAP upon interaction with PSAP at the mitochondria, leading to cytochrome c release and eventually apoptosis.
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Affiliation(s)
- Jingtian Zhang
- Edmond H. Fischer Signal Transduction Laboratory, College of Life Sciences, Jilin University, Changchun, China
| | - Zhizhuang Joe Zhao
- Edmond H. Fischer Signal Transduction Laboratory, College of Life Sciences, Jilin University, Changchun, China.,Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Xueqi Fu
- Edmond H. Fischer Signal Transduction Laboratory, College of Life Sciences, Jilin University, Changchun, China
| | - Han Niu
- Edmond H. Fischer Signal Transduction Laboratory, College of Life Sciences, Jilin University, Changchun, China
| | - Chen Hu
- School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Yunzhou Dong
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Mei-Zhen Cui
- Department of Biology, College of Arts and Sciences, University of Texas of the Permian Basin, Odessa, TX, USA
| | - Fuqiang Zhang
- Scientific Research Centre of China-Japan Union Hospital, Jilin University, Changchun, China
| | - Linlin Zeng
- Edmond H. Fischer Signal Transduction Laboratory, College of Life Sciences, Jilin University, Changchun, China
| | - Xuemin Xu
- Department of Biology, College of Arts and Sciences, University of Texas of the Permian Basin, Odessa, TX, USA
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Korkotian E, Meshcheriakova A, Segal M. Presenilin 1 Regulates [Ca 2+]i and Mitochondria/ER Interaction in Cultured Rat Hippocampal Neurons. Oxid Med Cell Longev 2019; 2019:7284967. [PMID: 31467635 DOI: 10.1155/2019/7284967] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/26/2019] [Accepted: 06/11/2019] [Indexed: 01/17/2023]
Abstract
Mutations in the presenilin 1 (PS1) gene are a major trigger of familial Alzheimer's disease (AD), yet the mechanisms affected by mutated PS1 causing cognitive decline are not yet elucidated. In the present study, we compared rat hippocampal neurons in culture, transfected with PS1 or with mutant (M146V) PS1 (mPS1) plasmids in several neuronal functions. Initially, we confirmed earlier observations that mPS1-expressing neurons are endowed with fewer mature “mushroom” spines and more filopodial immature protrusions. The correlation between calcium changes in the cytosol, mitochondria, and endoplasmic reticulum (ER) is mitigated in the mPS1 neurons, tested by the response to an abrupt increase in ambient [Ca2+]o; cytosolic [Ca2+]i is higher in the mPS1 neurons but mitochondrial [Ca2+] is lower than in control neurons. Strikingly, mPS1-transfected neurons express higher excitability and eventual lower survival rate when exposed to the oxidative stressor, paraquat. These results highlight an impaired calcium regulation in mPS1 neurons, resulting in a reduced ability to handle oxidative stress, which may lead to cell death and AD.
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Karch CM, Ezerskiy LA, Bertelsen S, Goate AM. Alzheimer's Disease Risk Polymorphisms Regulate Gene Expression in the ZCWPW1 and the CELF1 Loci. PLoS One 2016; 11:e0148717. [PMID: 26919393 PMCID: PMC4769299 DOI: 10.1371/journal.pone.0148717] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 12/17/2015] [Indexed: 11/18/2022] Open
Abstract
Late onset Alzheimer’s disease (LOAD) is a genetically complex and clinically heterogeneous disease. Recent large-scale genome wide association studies (GWAS) have identified more than twenty loci that modify risk for AD. Despite the identification of these loci, little progress has been made in identifying the functional variants that explain the association with AD risk. Thus, we sought to determine whether the novel LOAD GWAS single nucleotide polymorphisms (SNPs) alter expression of LOAD GWAS genes and whether expression of these genes is altered in AD brains. The majority of LOAD GWAS SNPs occur in gene dense regions under large linkage disequilibrium (LD) blocks, making it unclear which gene(s) are modified by the SNP. Thus, we tested for brain expression quantitative trait loci (eQTLs) between LOAD GWAS SNPs and SNPs in high LD with the LOAD GWAS SNPs in all of the genes within the GWAS loci. We found a significant eQTL between rs1476679 and PILRB and GATS, which occurs within the ZCWPW1 locus. PILRB and GATS expression levels, within the ZCWPW1 locus, were also associated with AD status. Rs7120548 was associated with MTCH2 expression, which occurs within the CELF1 locus. Additionally, expression of several genes within the CELF1 locus, including MTCH2, were highly correlated with one another and were associated with AD status. We further demonstrate that PILRB, as well as other genes within the GWAS loci, are most highly expressed in microglia. These findings together with the function of PILRB as a DAP12 receptor supports the critical role of microglia and neuroinflammation in AD risk.
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Affiliation(s)
- Celeste M. Karch
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Hope Center Program on Protein Aggregation and Neurodegeneration, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail: (CMK); (AMG)
| | - Lubov A. Ezerskiy
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Sarah Bertelsen
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, 1425 Madison Avenue, New York, NY 10029, United States of America
| | | | - Alison M. Goate
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, 1425 Madison Avenue, New York, NY 10029, United States of America
- * E-mail: (CMK); (AMG)
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5
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Zeng L, Hu C, Zhang F, Xu DC, Cui MZ, Xu X. Cellular FLICE-like Inhibitory Protein (c-FLIP) and PS1-associated Protein (PSAP) Mediate Presenilin 1-induced γ-Secretase-dependent and -independent Apoptosis, Respectively. J Biol Chem 2015; 290:18269-80. [PMID: 26025363 DOI: 10.1074/jbc.m115.640177] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Indexed: 12/21/2022] Open
Abstract
Presenilin 1 (PS1) has been implicated in apoptosis; however, its mechanism remains elusive. We report that PS1-induced apoptosis was associated with cellular FLICE-like inhibitory protein (c-FLIP) turnover and that γ-secretase inhibitor blocked c-FLIP turnover and also partially blocked PS1-induced apoptosis. A complete inhibition of PS1-induced apoptosis was achieved by knockdown of PS1-associated protein (PSAP), a mitochondrial proapoptotic protein that forms a complex with Bax upon induction of apoptosis, in the presence of γ-secretase inhibitor. PS1-induced apoptosis was partially inhibited by knockdown of caspase-8, Fas-associated protein with death domain (FADD), or Bid. However, knockdown of Bax or overexpression of Bcl-2 resulted in complete inhibition of PS1-induced apoptosis. These data suggest that PS1 induces apoptosis through two pathways: the γ-secretase-dependent pathway mediated by turnover of c-FLIP and the γ-secretase-independent pathway mediated by PSAP-Bax complex formation. These two pathways converge on Bax to activate mitochondria-dependent apoptosis. These findings provide new insight into the mechanisms by which PS1 is involved in apoptosis and the mechanism by which PS1 exerts its pathogenic effects. In addition, our results suggest that PS2 induces apoptosis through a pathway that is different from that of PS1.
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Affiliation(s)
- Linlin Zeng
- From the Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, and
| | - Chen Hu
- From the Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, and the Department of Comparative and Experimental Medicine, University of Tennessee, Knoxville, Tennessee 37996 and
| | - Fuqiang Zhang
- From the Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, and
| | - Daniel C Xu
- the Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544
| | - Mei-Zhen Cui
- From the Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, and
| | - Xuemin Xu
- From the Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, and
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Echenique-Robba P, Nelo-Bazán MA, Carrodeguas JA. Reducing the standard deviation in multiple-assay experiments where the variation matters but the absolute value does not. PLoS One 2013; 8:e78205. [PMID: 24205158 PMCID: PMC3813515 DOI: 10.1371/journal.pone.0078205] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 09/10/2013] [Indexed: 11/18/2022] Open
Abstract
When the value of a quantity x for a number of systems (cells, molecules, people, chunks of metal, DNA vectors, so on) is measured and the aim is to replicate the whole set again for different trials or assays, despite the efforts for a near-equal design, scientists might often obtain quite different measurements. As a consequence, some systems' averages present standard deviations that are too large to render statistically significant results. This work presents a novel correction method of a very low mathematical and numerical complexity that can reduce the standard deviation of such results and increase their statistical significance. Two conditions are to be met: the inter-system variations of x matter while its absolute value does not, and a similar tendency in the values of x must be present in the different assays (or in other words, the results corresponding to different assays must present a high linear correlation). We demonstrate the improvements this method offers with a cell biology experiment, but it can definitely be applied to any problem that conforms to the described structure and requirements and in any quantitative scientific field that deals with data subject to uncertainty.
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Affiliation(s)
- Pablo Echenique-Robba
- Instituto de Química Física Rocasolano, Consejo Superior de Investigaciones Científicas, Madrid, Spain
- Instituto de Biocomputación y Física de Sistemas Complejos, Universidad de Zaragoza, Zaragoza, Spain
- Zaragoza Scientific Center for Advanced Modeling, Universidad de Zaragoza, Zaragoza, Spain
- Departamento de Fsica Teórica, Universidad de Zaragoza, Zaragoza, Spain
- Unidad Asociada IQFR-BIFI, Madrid-Zaragoza, Spain
- * E-mail:
| | - María Alejandra Nelo-Bazán
- Instituto de Biocomputación y Física de Sistemas Complejos, Universidad de Zaragoza, Zaragoza, Spain
- Fundación Gran Mariscal de Ayacucho (Fundayacucho), La Urbina, Venezuela
- Departamento de Bioqumica y Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain
| | - José A. Carrodeguas
- Instituto de Biocomputación y Física de Sistemas Complejos, Universidad de Zaragoza, Zaragoza, Spain
- Unidad Asociada IQFR-BIFI, Madrid-Zaragoza, Spain
- Departamento de Bioqumica y Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain
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Hodas JJL, Nehring A, Höche N, Sweredoski MJ, Pielot R, Hess S, Tirrell DA, Dieterich DC, Schuman EM. Dopaminergic modulation of the hippocampal neuropil proteome identified by bioorthogonal noncanonical amino acid tagging (BONCAT). Proteomics 2012; 12:2464-76. [PMID: 22744909 DOI: 10.1002/pmic.201200112] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Local protein synthesis and its activity-dependent modulation via dopamine receptor stimulation play an important role in synaptic plasticity - allowing synapses to respond dynamically to changes in their activity patterns. We describe here the metabolic labeling, enrichment, and MS-based identification of candidate proteins specifically translated in intact hippocampal neuropil sections upon treatment with the selective D1/D5 receptor agonist SKF81297. Using the noncanonical amino acid azidohomoalanine and click chemistry, we identified over 300 newly synthesized proteins specific to dendrites and axons. Candidates specific for the SKF81297-treated samples were predominantly involved in protein synthesis and synapse-specific functions. Furthermore, we demonstrate a dendrite-specific increase in proteins synthesis upon application of SKF81297. This study provides the first snapshot in the dynamics of the dopaminergic hippocampal neuropil proteome.
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Affiliation(s)
- Jennifer J L Hodas
- Division of Biology, California Institute of Technology, Pasadena, CA, USA
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8
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Ospina A, Lagunas-Martínez A, Pardo J, Carrodeguas JA. Protein oligomerization mediated by the transmembrane carboxyl terminal domain of Bcl-XL. FEBS Lett 2011; 585:2935-42. [PMID: 21856303 PMCID: PMC7164028 DOI: 10.1016/j.febslet.2011.08.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 07/28/2011] [Accepted: 08/09/2011] [Indexed: 12/22/2022]
Abstract
Bcl-XL is a pro-survival member of the Bcl-2 family that can be found in the outer mitochondrial membrane and in soluble cytosolic homodimers. Bcl-XL can bind pro-apoptotic members of this family preventing them from activating the execution phase of apoptosis. Bcl-XL has been shown to homodimerize in different ways, although most binding and structural assays have been carried out in the absence of its carboxyl terminal transmembrane domain. We show here that this domain can by itself direct protein oligomerization, which could be related to its previously reported role in mitochondrial morphology alterations and apoptosis inhibition. Structured summary of protein interactions Vamp2 physically interacts with Vamp2 by blue native page (View interaction) Vamp2 physically interacts with Vamp2 by cross-linking study (View interaction) Bcl-Xl physically interacts with Bcl-Xl by blue native page (View interaction) Bcl-Xl physically interacts with Bcl-Xl by cross-linking study (View interaction)
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Affiliation(s)
- Angélica Ospina
- Institute for Biocomputation and Physics of Complex Systems, Edificio I+D, University of Zaragoza, Zaragoza, Spain
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Proctor DT, Coulson EJ, Dodd PR. Post-synaptic scaffolding protein interactions with glutamate receptors in synaptic dysfunction and Alzheimer's disease. Prog Neurobiol 2011; 93:509-21. [PMID: 21382433 DOI: 10.1016/j.pneurobio.2011.02.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 02/18/2011] [Accepted: 02/24/2011] [Indexed: 11/19/2022]
Abstract
Alzheimer's disease (AD) is characterized clinically by an insidious decline in cognition. Much attention has been focused on proposed pathogenic mechanisms that relate Aβ plaque and neurofibrillary tangle pathology to cognitive symptoms, but compelling evidence now identifies early synaptic loss and dysfunction, which precede plaque and tangle formation, as the more probable initiators of cognitive impairment. Glutamate-mediated transmission is severely altered in AD. Glutamate receptor expression is most markedly altered in regions of the AD brain that show the greatest pathological changes. Signaling via glutamate receptors controls synaptic strength and plasticity, and changes in these parameters are likely to contribute to memory and cognitive deficits in AD. Glutamate receptor expression and activity are modulated by interactions with post-synaptic scaffolding proteins that augment the strength and direction of signal cascades initiated by glutamate receptor activity. Scaffold proteins offer promising targets for more focused and effective drug therapy. In consequence, interest is developing into the roles these proteins play in neurological disease. In this review we discuss disruptions to excitatory neurotransmission at the level of glutamate receptor-post-synaptic scaffolding protein interactions that may contribute to synaptic dysfunction in AD.
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Affiliation(s)
- Dustin T Proctor
- School of Chemistry and Molecular Biosciences, Molecular Biosciences Building #76, Coopers Road, St Lucia campus, University of Queensland, Brisbane 4072, Australia
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10
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Carpenter G, Liao HJ. Trafficking of receptor tyrosine kinases to the nucleus. Exp Cell Res 2008; 315:1556-66. [PMID: 18951890 DOI: 10.1016/j.yexcr.2008.09.027] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 09/17/2008] [Accepted: 09/19/2008] [Indexed: 12/23/2022]
Abstract
It has been known for at least 20 years that growth factors induce the internalization of cognate receptor tyrosine kinases (RTKs). The internalized receptors are then sorted to lysosomes or recycled to the cell surface. More recently, data have been published to indicate other intracellular destinations for the internalized RTKs. These include the nucleus, mitochondria, and cytoplasm. Also, it is recognized that trafficking to these novel destinations involves new biochemical mechanisms, such as proteolytic processing or interaction with translocons, and that these trafficking events have a function in signal transduction, implicating the receptor itself as a signaling element between the cell surface and the nucleus.
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Affiliation(s)
- Graham Carpenter
- Department of Biochemistry, Vanderbilt University Medical Center, Nashville, Tennessee 37232-0146, USA.
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Lamarca V, Marzo I, Sanz-Clemente A, Carrodeguas JA. Exposure of any of two proapoptotic domains of presenilin 1-associated protein/mitochondrial carrier homolog 1 on the surface of mitochondria is sufficient for induction of apoptosis in a Bax/Bak-independent manner. Eur J Cell Biol 2008; 87:325-34. [PMID: 18375015 DOI: 10.1016/j.ejcb.2008.02.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2007] [Revised: 02/01/2008] [Accepted: 02/06/2008] [Indexed: 10/22/2022] Open
Abstract
Presenilin 1-associated protein/mitochondrial carrier homolog 1 (PSAP/Mtch1) is a proapoptotic outer mitochondrial membrane protein first identified as a presenilin 1-associated protein. The mechanism by which it induces apoptosis upon overexpression in cultured cells is so far unknown. We had previously reported that deletion of two independent regions of PSAP/Mtch1 is required to prevent apoptosis. We now report that mitochondrial targeting of the region containing both proapoptotic domains, or any of them independently, to the outer membrane is sufficient to induce apoptosis. On the other hand, targeting of that region to the surface of the endoplasmic reticulum does not induce apoptosis, indicating that attachment of those domains to the outer mitochondrial membrane, and not just cytosolic exposure, is a requisite for apoptosis. Overexpression of PSAP/Mtch1 in cultured cells causes mitochondrial depolarization and apoptosis that does not depend on Bax or Bak, since apoptosis is induced in mouse embryonic fibroblasts lacking these two proteins. Our results suggest that apoptosis induced by PSAP/Mtch1 likely involves the permeability transition pore.
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Affiliation(s)
- Violeta Lamarca
- Institute for Biocomputation and Physics of Complex Systems, University of Zaragoza, Corona de Aragón, 42, Edificio Cervantes, E-50009 Zaragoza, Spain
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Mao G, Tan J, Gao W, Shi Y, Cui MZ, Xu X. Both the N-terminal fragment and the protein-protein interaction domain (PDZ domain) are required for the pro-apoptotic activity of presenilin-associated protein PSAP. Biochim Biophys Acta Gen Subj 2008; 1780:696-708. [PMID: 18291114 DOI: 10.1016/j.bbagen.2008.01.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Revised: 01/16/2008] [Accepted: 01/17/2008] [Indexed: 11/25/2022]
Abstract
Presenilin-associated protein (PSAP) was originally identified as a PS1-associated, PDZ domain protein. In a subsequent study, PSAP was found to be a mitochondrial apoptotic molecule. In this study, we cloned the PSAP gene and found that it is composed of 12 exons and localizes on chromosome 6. To better understand the structure and function of PSAP, we have generated a series of antibodies that recognize different regions of PSAP. Using these antibodies, we found that PSAP is expressed in four isoforms as a result of differential splicing of exon 8 in addition to the use of either the first or the second ATG codon as the start codon. We also found that all these isoforms are localized in the mitochondria and are pro-apoptotic. Furthermore, our data revealed that the PDZ domain and N-terminal fragment are required for the pro-apoptotic activity of PSAP.
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Affiliation(s)
- Guozhang Mao
- Department of Pathobiology, College of Veterinary Medicine, The University of Tennessee, 2407 River Dr., Knoxville, TN 37996, USA
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Leibowitz-Amit R, Tsarfaty G, Abargil Y, Yerushalmi GM, Horev J, Tsarfaty I. Mimp, a mitochondrial carrier homologue, inhibits Met-HGF/SF-induced scattering and tumorigenicity by altering Met-HGF/SF signaling pathways. Cancer Res 2007; 66:8687-97. [PMID: 16951184 DOI: 10.1158/0008-5472.can-05-2294] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have recently shown that Mimp, a mitochondrial carrier protein homologue, is induced by Met-hepatocyte growth factor/scatter factor (HGF/SF) signaling and decreases the mitochondrial membrane potential in DA3 mammary adenocarcinoma cells. We show here that induction of Mimp leads to growth arrest in response to HGF/SF by arresting cells at the S phase of the cell cycle. Induction of Mimp or its transient expression does not lead to apoptosis. Mimp also attenuates HGF/SF-induced cellular scattering in vitro and tumor growth in vivo. The exogenous induction of Mimp at levels similar to its endogenous induction by HGF/SF increases the level of the Met protein and its phosphorylation by HGF/SF but reduces the levels of Shc and prevents the HGF/SF-induced tyrosine phosphorylation of Grb2 and Shc. In contrast, the level of phosphatidylinositol 3-kinase (PI3K) increases following Mimp induction and the level of phosphorylated PI3K in response to HGF/SF is unaffected by the exogenous induction of Mimp. Moreover, exogenous Mimp prevents the HGF/SF-induced transcription of the serum response element-luciferase reporter gene. Our results show that Mimp expression reduces Met-HGF/SF-induced proliferation and scattering by attenuating and altering the downstream signaling of Met. These data show a new link between a tyrosine kinase growth factor receptor and a mitochondrial carrier homologue that regulates cellular growth, motility, and tumorigenicity.
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Affiliation(s)
- Raya Leibowitz-Amit
- Department of Human Microbiology, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel
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14
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Lamarca V, Sanz-Clemente A, Pérez-Pé R, Martínez-Lorenzo MJ, Halaihel N, Muniesa P, Carrodeguas JA. Two isoforms of PSAP/MTCH1 share two proapoptotic domains and multiple internal signals for import into the mitochondrial outer membrane. Am J Physiol Cell Physiol 2007; 293:C1347-61. [PMID: 17670888 DOI: 10.1152/ajpcell.00431.2006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Presenilin 1-associated protein (PSAP) was first identified as a protein that interacts with presenilin 1. It was later reported that PSAP is a mitochondrial protein that induces apoptosis when overexpressed in cultured cells. PSAP is also known as mitochondrial carrier homolog 1 (Mtch1). In this study, we show that there are two proapoptotic PSAP isoforms generated by alternative splicing that differ in the length of a hydrophilic loop located between two predicted transmembrane domains. Using RT-PCR and Western blot assays, we determined that both isoforms are expressed in human and rat tissues as well as in culture cells. Our results indicate that PSAP is an integral mitochondrial outer membrane protein, although it contains a mitochondrial carrier domain conserved in several inner membrane carriers, which partially overlaps one of the predicted transmembrane segments. Deletion of this transmembrane segment impairs mitochondrial import of PSAP. Replacement of this segment with each of two transmembrane domains, with opposite membrane orientations, from an unrelated protein indicated that one of them allowed mitochondrial localization of the PSAP mutant, whereas the other one did not. Our interpretation of these results is that PSAP contains multiple mitochondrial targeting motifs dispersed along the protein but that a transmembrane domain in the correct position and orientation is necessary for membrane insertion. The amino acid sequence within this transmembrane domain may also be important. Furthermore, two independent regions in the amino terminal side of the protein are responsible for its proapoptotic activity. Possible implications of these findings in PSAP function are discussed.
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Affiliation(s)
- Violeta Lamarca
- Institute for Biocomputation and Physics of Complex Systems, University of Zaragoza, Corona de Aragón 42, Edificio Cervantes, 50009, Zaragoza, Spain
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15
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Abstract
The biogenesis and accumulation of the beta amyloid protein (Abeta) is a key event in the cascade of oxidative and inflammatory processes that characterises Alzheimer's disease. The presenilins and its interacting proteins play a pivotal role in the generation of Abeta from the amyloid precursor protein (APP). In particular, three proteins (nicastrin, aph-1 and pen-2) interact with presenilins to form a large multi-subunit enzymatic complex (gamma-secretase) that cleaves APP to generate Abeta. Reconstitution studies in yeast and insect cells have provided strong evidence that these four proteins are the major components of the gamma-secretase enzyme. Current research is directed at elucidating the roles that each of these protein play in the function of this enzyme. In addition, a number of presenilin interacting proteins that are not components of gamma-secretase play important roles in modulating Abeta production. This review will discuss the components of the gamma-secretase complex and the role of presenilin interacting proteins on gamma-secretase activity.
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Affiliation(s)
- Giuseppe Verdile
- Centre of Excellence for Alzheimer’s disease Research and Care, and the Sir James McCusker Alzheimer’s Disease Research Unit, School of Exercise, Biomedical and Health Sciences, Edith Cowan University, 100 Joondalup Drive, Joondalup, 6027 WA Australia
- Hollywood Private Hospital, Nedlands, WA Australia
- School of Psychiatry and Clinical Neurosciences, University of Western Australia, Crawley, WA Australia
| | - Samuel E Gandy
- Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA USA
| | - Ralph N. Martins
- Centre of Excellence for Alzheimer’s disease Research and Care, and the Sir James McCusker Alzheimer’s Disease Research Unit, School of Exercise, Biomedical and Health Sciences, Edith Cowan University, 100 Joondalup Drive, Joondalup, 6027 WA Australia
- Hollywood Private Hospital, Nedlands, WA Australia
- School of Psychiatry and Clinical Neurosciences, University of Western Australia, Crawley, WA Australia
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16
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Spasic D, Tolia A, Dillen K, Baert V, De Strooper B, Vrijens S, Annaert W. Presenilin-1 Maintains a Nine-Transmembrane Topology throughout the Secretory Pathway. J Biol Chem 2006; 281:26569-77. [PMID: 16846981 DOI: 10.1074/jbc.m600592200] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Presenilin-1 is a polytopic membrane protein that assembles with nicastrin, PEN-2, and APH-1 into an active gamma-secretase complex required for intramembrane proteolysis of type I transmembrane proteins. Although essential for a correct understanding of structure-function relationships, its exact topology remains an issue of strong controversy. We revisited presenilin-1 topology by inserting glycosylation consensus sequences in human PS1 and expressing the obtained mutants in a presenilin-1 and 2 knock-out background. Based on the glycosylation status of these variants we provide evidence that presenilin-1 traffics through the Golgi after a conformational change induced by complex assembly. Based on our glycosylation variants of presenilin-1 we hypothesize that complex assembly occurs during transport between the endoplasmic reticulum and the Golgi apparatus. Furthermore, our data indicate that presenilin-1 has a nine-transmembrane domain topology with the COOH terminus exposed to the lumen/extracellular surface. This topology is independently underscored by lysine mutagenesis, cell surface biotinylation, and cysteine derivation strategies and is compatible with the different physiological functions assigned to presenilin-1.
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Affiliation(s)
- Dragana Spasic
- Laboratory of Membrane Trafficking, Department of Human Genetics, Gasthuisberg, Katholieke Universiteit Leuven/VIB11, B-3000 Leuven, Belgium
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17
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Laudon H, Hansson EM, Melén K, Bergman A, Farmery MR, Winblad B, Lendahl U, von Heijne G, Näslund J. A nine-transmembrane domain topology for presenilin 1. J Biol Chem 2005; 280:35352-60. [PMID: 16046406 DOI: 10.1074/jbc.m507217200] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Presenilin (PS) provides the catalytic core of the gamma-secretase complex. Gamma-secretase activity leads to generation of the amyloid beta-peptide, a key event implicated in the pathogenesis of Alzheimer disease. PS has ten hydrophobic regions, which can all theoretically form membrane-spanning domains. Various topology models have been proposed, and the prevalent view holds that PS has an eight-transmembrane (TM) domain organization; however, the precise topology has not been unequivocally determined. Previous topological studies are based on non-functional truncated variants of PS proteins fused to reporter domains, or immunocytochemical staining. In this study, we used a more subtle N-linked glycosylation scanning approach, which allowed us to assess the topology of functional PS1 molecules. Glycosylation acceptor sequences were introduced into full-length human PS1, and the results showed that the first hydrophilic loop is oriented toward the lumen of the endoplasmic reticulum, whereas the N terminus and large hydrophilic loop are in the cytosol. Although this is in accordance with most current models, our data unexpectedly revealed that the C terminus localized to the luminal side of the endoplasmic reticulum. Additional studies on the glycosylation pattern after TM domain deletions, combined with computer-based TM protein topology predictions and biotinylation assays of different PS1 mutants, led us to conclude that PS1 has nine TM domains and that the C terminus locates to the lumen/extracellular space.
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Affiliation(s)
- Hanna Laudon
- Department of Neurotec, Division of Experimental Geriatrics, Karolinska Institutet, Novum, SE-141 86 Huddinge, Sweden.
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18
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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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19
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Abstract
The transmembrane topology of presenilins is still the subject of debate despite many experimental topology studies using antibodies or gene fusions. The results from these studies are partly contradictory and consequently several topology models have been proposed. Studies of presenilin-interacting proteins have produced further contradiction, primarily regarding the location of the C-terminus. It is thus impossible to produce a topology model that agrees with all published data on presenilin. We have analyzed the presenilin topology through computational sequence analysis of the presenilin family and the homologous presenilin-like protein family. Members of these families are intramembrane-cleaving aspartyl proteases. Although the overall sequence homology between the two families is low, they share the conserved putative active site residues and the conserved 'PAL' motif. Therefore, the topology model for the presenilin-like proteins can give some clues about the presenilin topology. Here we propose a novel nine-transmembrane topology with the C-terminus in the extracytosolic space. This model has strong support from published data on gamma-secretase function and presenilin topology. Contrary to most presenilin topology models, we show that hydrophobic region X is probably a transmembrane segment. Consequently, the C-terminus would be located in the extracytosolic space. However, the last C-terminal amino acids are relatively hydrophobic and in conjunction with existing experimental data we cannot exclude the possibility that the extreme C-terminus could be buried within the gamma-secretase complex. This might explain the difficulties in obtaining consistent experimental evidence regarding the location of the C-terminal region of presenilin.
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Affiliation(s)
- Anna Henricson
- Center for Genomics and Bioinformatics, Karolinska Institutet, Stockholm, Sweden
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20
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Abstract
The structural requirements for presenilin (PS) to produce active presenilinase and gamma-secretase enzymes are poorly understood. Here we investigate the role the cytoplasmic C-terminal region of PS1 plays in PS1 activity. Deletion or addition of residues at the PS C-terminus has been reported to inhibit presenilinase endoproteolysis of PS and alter gamma-secretase activity. In this study, we use a sensitive assay in PS1/2KO MEFs to define a domain at the extreme C-terminus of PS1 that is essential for both presenilinase and gamma-secretase activities. Progressive deletion of the C-terminus demonstrated that removal of nine residues produces a PS1 molecule (458ST) that lacks both presenilinase processing and gamma-secretase cleavage of Notch and APP substrates. In contrast, removal of four or five residues had no effect (462ST, 463ST), while intermediate truncations partially inhibited PS1 activity. The 458ST mutant was unable to replace endogenous wtPS1 in HEK293 cells. Although 458ST was able to form a gamma-secretase complex, this complex was not matured, illustrated by mutant PS1 instability, lack of endoproteolysis, and little production of mature Nicastrin. These data indicate that the C-terminal end of PS1 is essential for Nicastrin trafficking and modification as well as the replacement of endogenous PS1 by PS1 transgenes.
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Affiliation(s)
- A L Brunkan
- Department of Psychiatry, Washington University School of Medicine, 660 S.Euclid B8134, St Louis, Mo 63110, Missouri, USA
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21
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Gupta S, Singh R, Datta P, Zhang Z, Orr C, Lu Z, Dubois G, Zervos AS, Meisler MH, Srinivasula SM, Fernandes-Alnemri T, Alnemri ES. The C-terminal Tail of Presenilin Regulates Omi/HtrA2 Protease Activity. J Biol Chem 2004; 279:45844-54. [PMID: 15294909 DOI: 10.1074/jbc.m404940200] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Presenilin mutations are responsible for most cases of autosomal dominant inherited forms of early onset Alzheimer disease. Presenilins play an important role in amyloid beta-precursor processing, NOTCH receptor signaling, and apoptosis. However, the molecular mechanisms by which presenilins regulate apoptosis are not fully understood. Here, we report that presenilin-1 (PS1) regulates the proteolytic activity of the serine protease Omi/HtrA2 through direct interaction with its regulatory PDZ domain. We show that a peptide corresponding to the cytoplasmic C-terminal tail of PS1 dramatically increases the proteolytic activity of Omi/HtrA2 toward the inhibitor of apoptosis proteins and beta-casein and induces cell death in an Omi/HtrA2-dependent manner. Consistent with these results, ectopic expression of full-length PS1, but not PS1 lacking the C-terminal PDZ binding motif, potentiated Omi/HtrA2-induced cell death. Our results suggest that the C terminus of PS1 is an activation peptide ligand for the PDZ domain of Omi/HtrA2 and may regulate the protease activity of Omi/HtrA2 after its release from the mitochondria during apoptosis. This mechanism of Omi/HtrA2 activation is similar to the mechanism of activation of the related bacterial DegS protease by the outer-membrane porins.
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Affiliation(s)
- Sanjeev Gupta
- Center for Apoptosis Research and the Department of Microbiology and Immunology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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22
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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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23
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Lamy L, Ticchioni M, Rouquette-Jazdanian AK, Samson M, Deckert M, Greenberg AH, Bernard A. CD47 and the 19 kDa interacting protein-3 (BNIP3) in T cell apoptosis. J Biol Chem 2003; 278:23915-21. [PMID: 12690108 DOI: 10.1074/jbc.m301869200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CD47 is a surface receptor that induces either coactivation or apoptosis in lymphocytes, depending on the ligand(s) bound. Interestingly, the apoptotic pathway is independent of caspase activation and cytochrome c release and is accompanied by early mitochondrial dysfunction with suppression of mitochondrial membrane potential (Deltapsim). Using CD47 as bait in a yeast two-hybrid system, we identified the Bcl-2 homology 3 (BH3)-only protein 19 kDa interacting protein-3 (BNIP3), a pro-apoptotic member of the Bcl-2 family, as a novel partner. Interaction between CD47 and the BH3-only protein was confirmed by immunoprecipitation analysis, and CD47-induced apoptosis was inhibited by attenuating BNIP3 expression with antisense oligonucleotides. Finally, we showed that the C-terminal domain of thrombospondin-1 (TSP-1), but not signal-regulatory protein (SIRPalpha1), is the ligand for CD47 involved in inducing cell death. Immunofluorescence analysis of CD47 and BNIP3 revealed a partial colocalization of both molecules under basal conditions. After T cell stimulation via CD47, BNIP3 translocates to the mitochondria to induce apoptosis. These results show that the BH3-dependent apoptotic pathways, previously shown to be activated by intracellular pro-apoptotic events, can also be turned on by surface receptors. This new pathway results in a fast induction of cell death resembling necrosis, which is likely to play an important role in lymphocyte regulation at inflammatory sites and/or in the vicinity of thrombosis.
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Affiliation(s)
- Laurence Lamy
- Unité INSERM 576 et Laboratoire d'Immunologie, 06202 Nice cedex 3, France
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24
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Keino H, Kishikawa M, Satoh M, Shimada A. Expression of presenilin 1 and synapse-related proteins during postnatal development is not different between accelerated senescence-prone and -resistant mice. Neuropathology 2003; 23:16-24. [PMID: 12722922 DOI: 10.1046/j.1440-1789.2003.00482.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SAMP1TA/Ngs is an inbred strain of senescence-accelerated mice in which there is delayed development of cognitive functions and dendritic spine formation compared with normal control SAMR1TA//Ngs mice. It is hypothesized that abnormalities might be in the postnatal expression of synapse-related proteins in SAMP1TA/Ngs mice. Quantitative western blot analyses showed that the postnatal developmental changes in the expression of synaptophysin, post-synaptic density protein 95 and presenilin 1 in the cerebrum were similar between SAMP1TA/Ngs and SAMR1TA//Ngs mice. Therefore, the expression of synapse-related proteins was not disturbed in SAMP1TA/ Ngs mice regardless of reported abnormal numbers of dendritic spines during postnatal development. Immunohistochemical studies showed that the expression of synaptophysin in the neuropil increased postnatally with development in the same way in SAMP1TA/Ngs and SAMR1TA//Ngs mice. Presenilin 1 expression was relatively high at age 5 days in the neuropil of the cerebral cortex and decreased with postnatal development in the same way in SAMP1TA/Ngs and SAMR1TA//Ngs mice. At age 5 days the distribution of presenilin 1 was similar to the distribution of synaptophysin in that there were two separate immunoreactive patterns: a subpial band and patches in the middle layers reminiscent of barrels. These findings suggest that presenilin 1 is transiently expressed in the neuropil to induce synaptogenesis, and then its expression decreases overall.
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Affiliation(s)
- Hiromi Keino
- Department of Pathology, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Aichi, Japan
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25
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Abstract
The ErbB-4 receptor tyrosine kinase has a PDZ domain recognition motif at its carboxyl terminus. The first step in ErbB-4 proteolytic processing is a metalloprotease-dependent cleavage of the receptor ectodomain, which is not influenced by deletion of this motif. Metalloprotease cleavage of ErbB-4 produces a membrane-associated 80-kDa fragment that is a substrate for subsequent gamma-secretase cleavage, which releases the cytoplasmic domain from the membrane and allows nuclear translocation of this fragment. Deletion of the PDZ domain recognition motif does abrogate the gamma-secretase cleavage of ErbB-4. The wild-type 80-kDa ErbB-4 fragment forms an association complex with presenilin, thought to be the catalytic moiety of gamma-secretase activity. However, this association is significantly impaired by loss of the PDZ domain recognition motif from ErbB-4. Deletion of this ErbB-4 motif prevents the nuclear localization of the ErbB-4 cytoplasmic domain. Data also show that the basal cleavage of wild-type ErbB-4 by this proteolytic system can produce a sufficient level of ErbB-4 processing to negatively influence cell growth and that loss of the PDZ domain recognition motif abrogates this response.
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Affiliation(s)
- Chang-Yuan Ni
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA
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26
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Xu X, Shi YC, Gao W, Mao G, Zhao G, Agrawal S, Chisolm GM, Sui D, Cui MZ. The novel presenilin-1-associated protein is a proapoptotic mitochondrial protein. J Biol Chem 2002; 277:48913-22. [PMID: 12377771 DOI: 10.1074/jbc.m209613200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recent studies have suggested a possible role for presenilin proteins in apoptotic cell death observed in Alzheimer's disease. The mechanism by which presenilin proteins regulate apoptotic cell death is not well understood. Using the yeast two-hybrid system, we previously isolated a novel protein, presenilin-associated protein (PSAP) that specifically interacts with the C terminus of presenilin 1 (PS1), but not presenilin 2 (PS2). Here we report that PSAP is a mitochondrial resident protein sharing homology with mitochondrial carrier protein. PSAP was detected in a mitochondria-enriched fraction, and PSAP immunofluorescence was present in a punctate pattern that colocalized with a mitochondrial marker. More interestingly, overexpression of PSAP caused apoptotic death. PSAP-induced apoptosis was documented using multiple independent approaches, including membrane blebbing, chromosome condensation and fragmentation, DNA laddering, cleavage of the death substrate poly(ADP-ribose) polymerase, and flow cytometry. PSAP-induced cell death was accompanied by cytochrome c release from mitochondria and caspase-3 activation. Moreover, the general caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, which blocked cell death, did not block the release of cytochrome c from mitochondria caused by overexpression of PSAP, indicating that PSAP-induced cytochrome c release was independent of caspase activity. The mitochondrial localization and proapoptotic activity of PSAP suggest that it is an important regulator of apoptosis.
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Affiliation(s)
- Xuemin Xu
- Department of Pathology, College of Veterinary Medicine, University of Tennessee, Knoxville 37996, USA
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27
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Yerushalmi GM, Leibowitz-Amit R, Shaharabany M, Tsarfaty I. Met-HGF/SF signal transduction induces mimp, a novel mitochondrial carrier homologue, which leads to mitochondrial depolarization. Neoplasia 2002; 4:510-22. [PMID: 12407445 PMCID: PMC1503665 DOI: 10.1038/sj.neo.7900272] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2002] [Accepted: 07/01/2002] [Indexed: 01/17/2023]
Abstract
Met-hepatocyte growth factor/scatter factor (HGF/SF) signaling plays an important role in epithelial tissue morphogenesis, lumen formation, and tumorigenicity. We have recently demonstrated that HGF/SF also alters the metabolic activity of cells by enhancing both the glycolytic and oxidative phosphorylation pathways of energy production. Using differential display polymerase chain reaction, we cloned a novel gene, designated mimp (Met-Induced Mitochondrial Protein), which is upregulated in NIH-3T3 cells cotransfected with both HGF/SF and Met (HMH cells). Northern and Western blot analyses showed that mimp is induced in several Met-expressing cell lines following treatment with HGF/SF. Mimp encodes a 33-kDa protein that shows sequence homology to the family of mitochondrial carrier proteins (MCPs). Murine Mimp (mMimp) is expressed in a wide variety of tissues, exhibiting an expression pattern similar to Met. Predominant expression is seen in liver, kidney, heart, skeletal muscle, and testis. Using immunostaining for HA-tagged mMimp and a GFP-mMimp chimeric protein as well as subcellular fractionation, we determined that Mimp is primarily localized to the mitochondria. Ectopic expression of mMimp in the Met-responsive adenocarcinoma cell line, DA3, reduced the mitochondrial membrane potential (uncoupling activity). The extent of the mitochondrial depolarization positively correlated with the level of Mimp expression. Our results demonstrate that Mimp is a novel mitochondrial carrier homologue upregulated by Met-HGF/SF signal transduction, which leads to mitochondrial depolarization, and suggest novel links among tyrosine kinase signaling, mitochondrial function, and cellular bioenergetics.
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Affiliation(s)
- Gil M Yerushalmi
- Department of Human Microbiology, Sackler Faculty of Medicine, Tel-Aviv University, Israel
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28
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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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29
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Yu H, Saura CA, Choi SY, Sun LD, Yang X, Handler M, Kawarabayashi T, Younkin L, Fedeles B, Wilson MA, Younkin S, Kandel ER, Kirkwood A, Shen J. APP processing and synaptic plasticity in presenilin-1 conditional knockout mice. Neuron 2001; 31:713-26. [PMID: 11567612 DOI: 10.1016/s0896-6273(01)00417-2] [Citation(s) in RCA: 197] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We have developed a presenilin-1 (PS1) conditional knockout mouse (cKO), in which PS1 inactivation is restricted to the postnatal forebrain. The PS1 cKO mouse is viable and exhibits no gross abnormalities. The carboxy-terminal fragments of the amyloid precursor protein differentially accumulate in the cerebral cortex of cKO mice, while generation of beta-amyloid peptides is reduced. Expression of Notch downstream effector genes, Hes1, Hes5, and Dll1, is unaffected in the cKO cortex. Although basal synaptic transmission, long-term potentiation, and long-term depression at hippocampal area CA1 synapses are normal, the PS1 cKO mice exhibit subtle but significant deficits in long-term spatial memory. These results demonstrate that inactivation of PS1 function in the adult cerebral cortex leads to reduced Abeta generation and subtle cognitive deficits without affecting expression of Notch downstream genes.
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Affiliation(s)
- H Yu
- Center for Neurologic Diseases, Brigham and Women's Hospital, Boston, MA 02115, USA
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30
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Ishii K, Lippa C, Tomiyama T, Miyatake F, Ozawa K, Tamaoka A, Hasegawa T, Fraser PE, Shoji S, Nee LE, Pollen DA, St George-Hyslop PH, Ii K, Ohtake T, Kalaria RN, Rossor MN, Lantos PL, Cairns NJ, Farrer LA, Mori H. Distinguishable effects of presenilin-1 and APP717 mutations on amyloid plaque deposition. Neurobiol Aging 2001; 22:367-76. [PMID: 11378241 DOI: 10.1016/s0197-4580(01)00216-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Both APP and PS-1 are causal genes for early-onset familial Alzheimer's disease (AD) and their mutation effects on cerebral Abeta deposition in the senile plaques were examined in human brains of 29 familial AD (23 PS-1, 6 APP) cases and 14 sporadic AD cases in terms of Abeta40 and Abeta42. Abeta isoform data were evaluated using repeated measures analysis of variance which adjusted for within-subject measurement variation and confounding effects of individual APP and PS-1 mutations, age at onset, duration of illness and APOE genotype. We observed that mutations in both APP and PS-1 were associated with a significant increase of Abeta42 in plaques as been documented previously. In comparison to sporadic AD cases, both APP717 and PS-1 mutation cases had an increased density (measured as the number of plaques/mm(2)) and area (%) of Abeta42 plaques. However, we found an unexpected differential effect of PS-1 but not APP717 mutation cases. At least some of PS-1 but not APP717 mutation cases had the significant increase of density and area of Abeta40-plaques as compared to sporadic AD independently of APOE genotype. Our results suggest that PS-1 mutations affect cerebral accumulation of Abeta burden in a different fashion from APP717 mutations in their familial AD brains.
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Affiliation(s)
- K Ishii
- Department of Molecular Biology, Tokyo Institute of Psychiatry, Tokyo, Japan
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31
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Abstract
Rapid progress in deciphering the biological mechanism of Alzheimer's disease (AD) has arisen from the application of molecular and cell biology to this complex disorder of the limbic and association cortices. In turn, new insights into fundamental aspects of protein biology have resulted from research on the disease. This beneficial interplay between basic and applied cell biology is well illustrated by advances in understanding the genotype-to-phenotype relationships of familial Alzheimer's disease. All four genes definitively linked to inherited forms of the disease to date have been shown to increase the production and/or deposition of amyloid beta-protein in the brain. In particular, evidence that the presenilin proteins, mutations in which cause the most aggressive form of inherited AD, lead to altered intramembranous cleavage of the beta-amyloid precursor protein by the protease called gamma-secretase has spurred progress toward novel therapeutics. The finding that presenilin itself may be the long-sought gamma-secretase, coupled with the recent identification of beta-secretase, has provided discrete biochemical targets for drug screening and development. Alternate and novel strategies for inhibiting the early mechanism of the disease are also emerging. The progress reviewed here, coupled with better ability to diagnose the disease early, bode well for the successful development of therapeutic and preventative drugs for this major public health problem.
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Affiliation(s)
- D J Selkoe
- Department of Neurology and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts, USA
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32
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Abstract
Cellular genes that are mutated in neurodegenerative diseases code for proteins that are expressed throughout neural development. Genetic analysis suggests that these genes are essential for a broad range of normal neurodevelopmental processes. The proteins they code for interact with numerous other cellular proteins that are components of signaling pathways involved in patterning of the neural tube and in regional specification of neuronal subtypes. Further, pathogenetic mutations of these genes can cause progressive, sublethal alterations in the cellular homeostasis of evolving regional neuronal subpopulations, culminating in late-onset cell death. Therefore, as a consequence of the disease mutations, targeted cell populations may retain molecular traces of abnormal interactions with disease-associated proteins by exhibiting changes in a spectrum of normal cellular functions and enhanced vulnerability to a host of environmental stressors. These observations suggest that the normal functions of these disease-associated proteins are to ensure the fidelity and integration of developmental events associated with the progressive elaboration of neuronal subtypes as well as the maintenance of mature neuronal populations during adult life. The ability to identify alterations within vulnerable neuronal precursors present in pre-symptomatic individuals prior to the onset of irrevocable cellular injury may help foster the development of effective therapeutic interventions using evolving pharmacologic, gene and stem cell technologies.
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Affiliation(s)
- M F Mehler
- Laboratory of Developmental and Molecular Neuroscience, Department of Neurology, Rose F. Kennedy Center for Research in Mental Retardation and Developmental Disabilities, Albert Einstein College of Medicine, Bronx 10461, NY, USA.
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33
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Abstract
X11 alpha and X11 beta are two neuronal adaptor proteins that interact with the Alzheimer's disease amyloid precursor protein (APP). X11 alpha and X11 beta stabilise APP and inhibit production of proteolytic APP fragments including the A beta peptide that is deposited in the brains of Alzheimer's disease patients. The mechanisms by which X11 alpha and X11 beta modulate APP processing are not clear but one possibility is that they influence the activity of the secretases that cleave APP to give rise to A beta. Presenilin-1 is required for gamma-secretase activity and here we demonstrate that both X11 alpha and X11 beta interact with presenilin-1. X11/presenilin-1 binding is via two X11 PDZ domains and sequences within the carboxy-terminus of presenilin-1. We also demonstrate that both X11 alpha and X11 beta mediate the formation of complexes between APP and presenilin-1. These results suggest that the X11 regulation of APP processing is controlled, at least in part, via their interactions with APP and presenilin-1.
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Affiliation(s)
- K F Lau
- Department of Neuroscience, Institute of Psychiatry, Denmark Hill, London SE5 8AF, United Kingdom
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34
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Abstract
Using the yeast two-hybrid system, we screened for proteins interacting with presenilin 2 (PS2) and cloned DRAL. DRAL is an LIM-only protein containing four LIM domains and an N-terminal half LIM domain. Previously DRAL has been cloned as a co-activator of the androgen receptor and as a protein interacting with a DNA replication regulatory protein, hCDC47. Our yeast two-hybrid assay showed that DRAL interacted with a hydrophilic loop region (amino acids 269-298) in the endoproteolytic N-terminal fragment of PS2, but not that of PS1, although the region 269-298 of PS2 and the corresponding PS1 sequence differ by only three amino acids. Each point mutation within this region, R275A, T280A, Q282A, R284A, N285A, P287T, I288L, F289A and S296A, in PS2 abolished the binding. This suggests that DRAL recognizes the PS2 structure specifically. The in vitro interaction was confirmed by affinity column assay and the physiological interactions between endogenous PS2 and DRAL by co-immunoprecipitation from human lung fibroblast MRC5 cells. Furthermore, in PS2-overexpressing HEK293 cells, we found an increase in the amount of DRAL in the membrane fraction and an increase in the amount of DRAL that was co-immunoprecipitated with PS2. The potential role of DRAL in the cellular signaling suggests that DRAL functions as an adaptor protein that links PS2 to an intracellular signaling.
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Affiliation(s)
- H Tanahashi
- Division of Demyelinating Disease and Aging, National Institute of Neuroscience, 4-1-1 Ogawahigashi, Kodaira, Tokyo 187-8502, Japan.
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35
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Gray CW, Ward RV, Karran E, Turconi S, Rowles A, Viglienghi D, Southan C, Barton A, Fantom KG, West A, Savopoulos J, Hassan NJ, Clinkenbeard H, Hanning C, Amegadzie B, Davis JB, Dingwall C, Livi GP, Creasy CL. Characterization of human HtrA2, a novel serine protease involved in the mammalian cellular stress response. Eur J Biochem 2000; 267:5699-710. [PMID: 10971580 DOI: 10.1046/j.1432-1327.2000.01589.x] [Citation(s) in RCA: 183] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Human HtrA2 is a novel member of the HtrA serine protease family and shows extensive homology to the Escherichia coli HtrA genes that are essential for bacterial survival at high temperatures. HumHtrA2 is also homologous to human HtrA1, also known as L56/HtrA, which is differentially expressed in human osteoarthritic cartilage and after SV40 transformation of human fibroblasts. HumHtrA2 is upregulated in mammalian cells in response to stress induced by both heat shock and tunicamycin treatment. Biochemical characterization of humHtrA2 shows it to be predominantly a nuclear protease which undergoes autoproteolysis. This proteolysis is abolished when the predicted active site serine residue is altered to alanine by site-directed mutagenesis. In human cell lines, it is present as two polypeptides of 38 and 40 kDa. HumHtrA2 cleaves beta-casein with an inhibitor profile similar to that previously described for E. coli HtrA, in addition to an increase in beta-casein turnover when the assay temperature is raised from 37 to 45 degrees C. The biochemical and sequence similarities between humHtrA2 and its bacterial homologues, in conjunction with its nuclear location and upregulation in response to tunicamycin and heat shock suggest that it is involved in mammalian stress response pathways.
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Affiliation(s)
- C W Gray
- SmithKline Beecham Pharmaceuticals, New Frontiers Science Park North, Harlow, Essex, UK
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36
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Abstract
Protein-protein interactions are a molecular basis for the structural and functional organization within cells. They are mediated by a growing number of protein modules that bind peptide targets. Alterations in binding affinities can have serious consequences for some essential cellular processes. The three proteins identified to have mutations in their corresponding genes leading to presenile Alzheimer dementia (AD)-the amyloid precursor protein (APP) and presenilin 1 and 2-all interact with other proteins. The nature and function of these interacting proteins may contribute to elucidating the proper physiological functions of the AD proteins. APP-interacting proteins are pointing toward a function of APP in cell adhesion and neurite outgrowth and signaling. Proteins interacting with the presenilins however are more diverse in nature linking presenilin function to regulation in different signaling pathways including Wnt and Notch but also in apoptosis and Ca(2+) homeostasis. Further research however is still needed to delineate the exact functional relevance of these interactions with respect to the physiological functions of the AD proteins in particular and the contribution of these proteins to AD pathogenesis in general.
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Affiliation(s)
- G Van Gassen
- Molecular Genetics Laboratory, University of Antwerp (UIA), Antwerpen, Belgium
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