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Weiß J, Heib M, Korn T, Hoyer J, Fuchslocher Chico J, Voigt S, Koudelka T, Tholey A, Adam D. Protease-independent control of parthanatos by HtrA2/Omi. Cell Mol Life Sci 2023; 80:258. [PMID: 37594630 PMCID: PMC10439076 DOI: 10.1007/s00018-023-04904-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/15/2023] [Accepted: 07/31/2023] [Indexed: 08/19/2023]
Abstract
HtrA2/Omi is a mitochondrial serine protease with ascribed pro-apoptotic as well as pro-necroptotic functions. Here, we establish that HtrA2/Omi also controls parthanatos, a third modality of regulated cell death. Deletion of HtrA2/Omi protects cells from parthanatos while reconstitution with the protease restores the parthanatic death response. The effects of HtrA2/Omi on parthanatos are specific and cannot be recapitulated by manipulating other mitochondrial proteases such as PARL, LONP1 or PMPCA. HtrA2/Omi controls parthanatos in a manner mechanistically distinct from its action in apoptosis or necroptosis, i.e., not by cleaving cytosolic IAP proteins but rather exerting its effects without exiting mitochondria, and downstream of PARP-1, the first component of the parthanatic signaling cascade. Also, previously identified or candidate substrates of HtrA2/Omi such as PDXDC1, VPS4B or moesin are not cleaved and dispensable for parthanatos, whereas DBC-1 and stathmin are cleaved, and thus represent potential parthanatic downstream mediators of HtrA2/Omi. Moreover, mass-spectrometric screening for novel parthanatic substrates of HtrA2/Omi revealed that the induction of parthanatos does not cause a substantial proteolytic cleavage or major alterations in the abundance of mitochondrial proteins. Resolving these findings, reconstitution of HtrA2/Omi-deficient cells with a catalytically inactive HtrA2/Omi mutant restored their sensitivity against parthanatos to the same level as the protease-active HtrA2/Omi protein. Additionally, an inhibitor of HtrA2/Omi's protease activity did not confer protection against parthanatic cell death. Our results demonstrate that HtrA2/Omi controls parthanatos in a protease-independent manner, likely via novel, unanticipated functions as a scaffolding protein and an interaction with so far unknown mitochondrial proteins.
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Affiliation(s)
- Jonas Weiß
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105, Kiel, Germany
| | - Michelle Heib
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105, Kiel, Germany
| | - Thiemo Korn
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105, Kiel, Germany
| | - Justus Hoyer
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105, Kiel, Germany
| | - Johaiber Fuchslocher Chico
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105, Kiel, Germany
| | - Susann Voigt
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105, Kiel, Germany
| | - Tomas Koudelka
- Institut für Experimentelle Medizin, Christian-Albrechts-Universität zu Kiel, Niemannsweg 11, 24105, Kiel, Germany
| | - Andreas Tholey
- Institut für Experimentelle Medizin, Christian-Albrechts-Universität zu Kiel, Niemannsweg 11, 24105, Kiel, Germany
| | - Dieter Adam
- Institut für Immunologie, Christian-Albrechts-Universität zu Kiel, Michaelisstr. 5, 24105, Kiel, Germany.
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Nam MK, Seong Y, Jeong GH, Yoo SA, Rhim H. HtrA2 regulates α-Synuclein-mediated mitochondrial reactive oxygen species production in the mitochondria of microglia. Biochem Biophys Res Commun 2023; 638:84-93. [PMID: 36442236 DOI: 10.1016/j.bbrc.2022.11.049] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 11/17/2022] [Indexed: 11/19/2022]
Abstract
Aggregation and misfolding of α-Synuclein (α-Syn), a causative agent for Parkinson's disease (PD), and oxidative stress are tightly implicated in the pathogenesis of PD. Although more than 20 genes including HtrA2 have been identified as causative genes for PD, the molecular mechanisms underlying the pathophysiological functions between HtrA2 and α-Syn in the pathogenesis of PD remain unclear. This study shows that HtrA2 serine protease selectively recognizes and interacts with the NAC region of α-Syn. Interestingly, we found that HtrA2 causes proteolysis of α-Syn to prevent mitochondrial accumulation of α-Syn, thereby inhibiting the production of reactive oxygen species (ROS) in the mitochondria. We have further demonstrated that HtrA2 knockdown promotes α-Syn-mediated mitochondrial ROS production, thereby activating microglial cells. This study is the first to demonstrate that the HtrA2/α-Syn cellular partner may play a crucial role in the pathogenesis of PD and provide new insights into the pathological processes and effective therapeutic strategies for PD.
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Affiliation(s)
- Min-Kyung Nam
- Department of Biomedicine & Health Sciences, Department of Medical Life Sciences, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Youngmo Seong
- Department of Biomedicine & Health Sciences, Department of Medical Life Sciences, College of Medicine, The Catholic University of Korea, Seoul, South Korea; Division of Life Sciences, College of Life Sciences and Biotechnology, Korea University, Seoul, South Korea
| | - Gi Heon Jeong
- Department of Biomedicine & Health Sciences, Department of Medical Life Sciences, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Seung-Ah Yoo
- Department of Biomedicine & Health Sciences, Department of Medical Life Sciences, College of Medicine, The Catholic University of Korea, Seoul, South Korea.
| | - Hyangshuk Rhim
- Department of Biomedicine & Health Sciences, Department of Medical Life Sciences, College of Medicine, The Catholic University of Korea, Seoul, South Korea.
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Nam MK, Moon JM, Kim GY, Kim SM, Rhim H. The novel human HtrA2 ortholog in zebrafish: New molecular insight and challenges into the imbalance of homeostasis. Gene 2022; 819:146263. [PMID: 35121025 DOI: 10.1016/j.gene.2022.146263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 01/17/2022] [Accepted: 01/27/2022] [Indexed: 11/28/2022]
Abstract
High temperature requirement A2 (HtrA2) contributes to regulating mitochondrial quality control and maintaining the balance between the death and survival of cells and living organisms. However, the molecular mechanism of HtrA2 in physiological and pathophysiological processes remains unclear. HtrA2 exhibits multifaceted characteristics according to the expression levels and acts opposite functions depending on its subcellular localization. Thus, innovative technologies and systems that can be freely manipulated at the quantitative, biochemical, molecular and cellular levels are needed to address not only the challenges faced by HtrA2 research but also the general obstacles to protein research. Here, we are the first to identify zebrafish HtrA2 (zHtrA2) as the true ortholog of human HtrA2 (hHtrA2), by in silico sequence analysis of genomic DNA and molecular biological techniques, which is highly conserved structurally and functionally as a serine protease and cell death regulator. The zHtrA2 protein is primarily localized in the mitochondria, where alanine-exposed mature zHtrA2 ((A)-zHtrA2) is generated by removing 111 residues at the N-terminus of pro-zHtrA2. The (A)-zHtrA2 released from the mitochondria into the cytosol induces the caspase cascade by binding to and inhibiting hXIAP, a cognate partner of hHtrA2. Notably, zHtrA2 has well conserved properties of serine protease that specifically cleaves hParkin, a cognate substrate of hHtrA2. Interestingly, cytosolic (M)-zHtrA2, which does not bind hXIAP, induces atypical cell death in a serine protease-dependent manner, as occurs in hHtrA2. Thus, the zebrafish-zHtrA2 system can be used to clarify the crucial role of HtrA2 in maintaining the survival of living organisms and provide an opportunity to develop novel therapeutics for HtrA2-associated diseases, such as neurodegenerative diseases and cancer, which are caused by dysregulation of HtrA2.
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Affiliation(s)
- Min-Kyung Nam
- Department of Medical Life Sciences, College of Medicine, The Catholic University of Korea, Seocho-gu, Seoul 06591, Republic of Korea.
| | - Jeong-Mi Moon
- Department of Medical Life Sciences, College of Medicine, The Catholic University of Korea, Seocho-gu, Seoul 06591, Republic of Korea
| | - Goo-Young Kim
- Department of Medical Life Sciences, College of Medicine, The Catholic University of Korea, Seocho-gu, Seoul 06591, Republic of Korea
| | - Sung Min Kim
- Department of Biomedicine & Health Sciences, The Catholic University of Korea, Seocho-gu, Seoul 06591, Republic of Korea
| | - Hyangshuk Rhim
- Department of Medical Life Sciences, College of Medicine, The Catholic University of Korea, Seocho-gu, Seoul 06591, Republic of Korea; Department of Biomedicine & Health Sciences, The Catholic University of Korea, Seocho-gu, Seoul 06591, Republic of Korea.
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4
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Mandal P, Nagrani LN, Hernandez L, McCormick AL, Dillon CP, Koehler HS, Roback L, Alnemri ES, Green DR, Mocarski ES. Multiple Autonomous Cell Death Suppression Strategies Ensure Cytomegalovirus Fitness. Viruses 2021; 13:v13091707. [PMID: 34578288 PMCID: PMC8473406 DOI: 10.3390/v13091707] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/13/2021] [Accepted: 08/20/2021] [Indexed: 12/31/2022] Open
Abstract
Programmed cell death pathways eliminate infected cells and regulate infection-associated inflammation during pathogen invasion. Cytomegaloviruses encode several distinct suppressors that block intrinsic apoptosis, extrinsic apoptosis, and necroptosis, pathways that impact pathogenesis of this ubiquitous herpesvirus. Here, we expanded the understanding of three cell autonomous suppression mechanisms on which murine cytomegalovirus relies: (i) M38.5-encoded viral mitochondrial inhibitor of apoptosis (vMIA), a BAX suppressor that functions in concert with M41.1-encoded viral inhibitor of BAK oligomerization (vIBO), (ii) M36-encoded viral inhibitor of caspase-8 activation (vICA), and (iii) M45-encoded viral inhibitor of RIP/RHIM activation (vIRA). Following infection of bone marrow-derived macrophages, the virus initially deflected receptor-interacting protein kinase (RIPK)3-dependent necroptosis, the most potent of the three cell death pathways. This process remained independent of caspase-8, although suppression of this apoptotic protease enhances necroptosis in most cell types. Second, the virus deflected TNF-mediated extrinsic apoptosis, a pathway dependent on autocrine TNF production by macrophages that proceeds independently of mitochondrial death machinery or RIPK3. Third, cytomegalovirus deflected BCL-2 family protein-dependent mitochondrial cell death through combined TNF-dependent and -independent signaling even in the absence of RIPK1, RIPK3, and caspase-8. Furthermore, each of these cell death pathways dictated a distinct pattern of cytokine and chemokine activation. Therefore, cytomegalovirus employs sequential, non-redundant suppression strategies to specifically modulate the timing and execution of necroptosis, extrinsic apoptosis, and intrinsic apoptosis within infected cells to orchestrate virus control and infection-dependent inflammation. Virus-encoded death suppressors together hold control over an intricate network that upends host defense and supports pathogenesis in the intact mammalian host.
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Affiliation(s)
- Pratyusha Mandal
- Emory Vaccine Center, Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA; (L.H.); (H.S.K.); (L.R.)
- Correspondence: (P.M.); (E.S.M.); Tel.: +404-727-0563 (P.M.); +404-727-4273 (E.S.M.)
| | | | - Liliana Hernandez
- Emory Vaccine Center, Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA; (L.H.); (H.S.K.); (L.R.)
| | | | | | - Heather S. Koehler
- Emory Vaccine Center, Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA; (L.H.); (H.S.K.); (L.R.)
| | - Linda Roback
- Emory Vaccine Center, Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA; (L.H.); (H.S.K.); (L.R.)
| | - Emad S. Alnemri
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA;
| | - Douglas R. Green
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA;
| | - Edward S. Mocarski
- Emory Vaccine Center, Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA; (L.H.); (H.S.K.); (L.R.)
- Correspondence: (P.M.); (E.S.M.); Tel.: +404-727-0563 (P.M.); +404-727-4273 (E.S.M.)
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Schmelter C, Fomo KN, Perumal N, Pfeiffer N, Grus FH. Regulation of the HTRA2 Protease Activity by an Inhibitory Antibody-Derived Peptide Ligand and the Influence on HTRA2-Specific Protein Interaction Networks in Retinal Tissues. Biomedicines 2021; 9:biomedicines9081013. [PMID: 34440217 PMCID: PMC8427973 DOI: 10.3390/biomedicines9081013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/03/2021] [Accepted: 08/10/2021] [Indexed: 02/06/2023] Open
Abstract
The mitochondrial serine protease HTRA2 has many versatile biological functions ranging from being an important regulator of apoptosis to being an essential component for neuronal cell survival and mitochondrial homeostasis. Loss of HTRA2 protease function is known to cause neurodegeneration, whereas overactivation of its proteolytic function is associated with cell death and inflammation. In accordance with this, our group verified in a recent study that the synthetic peptide ASGYTFTNYGLSWVR, encoding the hypervariable sequence part of an antibody, showed a high affinity for the target protein HTRA2 and triggered neuroprotection in an in vitro organ culture model for glaucoma. To unravel this neuroprotective mechanism, the present study showed for the first time that the synthetic CDR1 peptide significantly (p < 0.01) inhibited the proteolytic activity of HTRA2 up to 50% using a specific protease function assay. Furthermore, using state-of-the-art co-immunoprecipitation technologies in combination with high-resolution MS, we identified 50 significant protein interaction partners of HTRA2 in the retina of house swine (p < 0.01; log2 fold change > 1.5). Interestingly, 72% of the HTRA2-specific interactions (23 of 31 binders) were inhibited by additional treatment with UCF-101 (HTRA2 protease inhibitor) or the synthetic CDR peptide. On the other hand, the remaining 19 binders of HTRA2 were exclusively identified in the UCF101 and/or CDR group. However, many of the interactors were involved in the ER to Golgi anterograde transport (e.g., AP3D1), aggrephagy (e.g., PSMC1), and the pyruvate metabolism/citric acid cycle (e.g., SHMT2), and illustrated the complex protein interaction networks of HTRA2 in neurological tissues. In conclusion, the present study provides, for the first time, a comprehensive protein catalogue of HTRA2-specific interaction partners in the retina, and will serve as reference map in the future for studies focusing on HTRA2-mediated neurodegeneration.
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Hofsetz E, Demir F, Szczepanowska K, Kukat A, Kizhakkedathu JN, Trifunovic A, Huesgen PF. The Mouse Heart Mitochondria N Terminome Provides Insights into ClpXP-Mediated Proteolysis. Mol Cell Proteomics 2020; 19:1330-1345. [PMID: 32467259 PMCID: PMC8014998 DOI: 10.1074/mcp.ra120.002082] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/24/2020] [Indexed: 12/29/2022] Open
Abstract
The mammalian mitochondrial proteome consists of more than 1100 annotated proteins and their proteostasis is regulated by only a few ATP-dependent protease complexes. Technical advances in protein mass spectrometry allowed for detailed description of the mitoproteome from different species and tissues and their changes under specific conditions. However, protease-substrate relations within mitochondria are still poorly understood. Here, we combined Terminal Amine Isotope Labeling of Substrates (TAILS) N termini profiling of heart mitochondria proteomes isolated from wild type and Clpp-/- mice with a classical substrate-trapping screen using FLAG-tagged proteolytically active and inactive CLPP variants to identify new ClpXP substrates in mammalian mitochondria. Using TAILS, we identified N termini of more than 200 mitochondrial proteins. Expected N termini confirmed sequence determinants for mitochondrial targeting signal (MTS) cleavage and subsequent N-terminal processing after import, but the majority were protease-generated neo-N termini mapping to positions within the proteins. Quantitative comparison revealed widespread changes in protein processing patterns, including both strong increases or decreases in the abundance of specific neo-N termini, as well as an overall increase in the abundance of protease-generated neo-N termini in CLPP-deficient mitochondria that indicated altered mitochondrial proteostasis. Based on the combination of altered processing patterns, protein accumulation and stabilization in CLPP-deficient mice and interaction with CLPP, we identified OAT, HSPA9 and POLDIP2 and as novel bona fide ClpXP substrates. Finally, we propose that ClpXP participates in the cooperative degradation of UQCRC1. Together, our data provide the first landscape of the heart mitochondria N terminome and give further insights into regulatory and assisted proteolysis mediated by ClpXP.
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Affiliation(s)
- Eduard Hofsetz
- Institute for Mitochondrial Diseases and Aging at CECAD Research Centre, and Center for Molecular Medicine Cologne (CMMC), Medical Faculty, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), Cologne, Germany, Medical Faculty and University Hospital, University of Cologne, Cologne, Germany
| | - Fatih Demir
- Central Institute for Engineering, Electronics and Analytics, ZEA-3, Forschungszentrum Jülich, Germany
| | - Karolina Szczepanowska
- Institute for Mitochondrial Diseases and Aging at CECAD Research Centre, and Center for Molecular Medicine Cologne (CMMC), Medical Faculty, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), Cologne, Germany, Medical Faculty and University Hospital, University of Cologne, Cologne, Germany
| | - Alexandra Kukat
- Institute for Mitochondrial Diseases and Aging at CECAD Research Centre, and Center for Molecular Medicine Cologne (CMMC), Medical Faculty, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), Cologne, Germany, Medical Faculty and University Hospital, University of Cologne, Cologne, Germany
| | - Jayachandran N Kizhakkedathu
- Centre for Blood Research, School of Biomedical Engineering, Department of Pathology & Laboratory Medicine, Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Aleksandra Trifunovic
- Institute for Mitochondrial Diseases and Aging at CECAD Research Centre, and Center for Molecular Medicine Cologne (CMMC), Medical Faculty, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), Cologne, Germany, Medical Faculty and University Hospital, University of Cologne, Cologne, Germany.
| | - Pitter F Huesgen
- Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), Cologne, Germany, Medical Faculty and University Hospital, University of Cologne, Cologne, Germany; Central Institute for Engineering, Electronics and Analytics, ZEA-3, Forschungszentrum Jülich, Germany; Institute for Biochemistry, Faculty of Mathematics and Natural Sciences, University of Cologne, Cologne, Germany.
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7
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Yun SE, Nam MK, Rhim H. Quantitative biochemical characterization and biotechnological production of caspase modulator, XIAP: Therapeutic implications for apoptosis-associated diseases. Biochim Biophys Acta Gen Subj 2018; 1862:1602-1611. [DOI: 10.1016/j.bbagen.2018.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 04/03/2018] [Accepted: 04/05/2018] [Indexed: 12/26/2022]
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8
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Lebeau J, Rainbolt TK, Wiseman RL. Coordinating Mitochondrial Biology Through the Stress-Responsive Regulation of Mitochondrial Proteases. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 340:79-128. [PMID: 30072094 PMCID: PMC6402875 DOI: 10.1016/bs.ircmb.2018.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Proteases are localized throughout mitochondria and function as critical regulators of all aspects of mitochondrial biology. As such, the activities of these proteases are sensitively regulated through transcriptional and post-translational mechanisms to adapt mitochondrial function to specific cellular demands. Here, we discuss the stress-responsive mechanisms responsible for regulating mitochondrial protease activity and the implications of this regulation on mitochondrial function. Furthermore, we describe how imbalances in the activity or regulation of mitochondrial proteases induced by genetic, environmental, or aging-related factors influence mitochondria in the context of disease. Understanding the molecular mechanisms by which cells regulate mitochondrial function through alterations in protease activity provide insights into the contributions of these proteases in pathologic mitochondrial dysfunction and reveals new therapeutic opportunities to ameliorate this dysfunction in the context of diverse classes of human disease.
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Affiliation(s)
- Justine Lebeau
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - T Kelly Rainbolt
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - R Luke Wiseman
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
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9
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Szoradi T, Schaeff K, Garcia-Rivera EM, Itzhak DN, Schmidt RM, Bircham PW, Leiss K, Diaz-Miyar J, Chen VK, Muzzey D, Borner GHH, Schuck S. SHRED Is a Regulatory Cascade that Reprograms Ubr1 Substrate Specificity for Enhanced Protein Quality Control during Stress. Mol Cell 2018; 70:1025-1037.e5. [PMID: 29861160 DOI: 10.1016/j.molcel.2018.04.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 03/12/2018] [Accepted: 04/27/2018] [Indexed: 12/31/2022]
Abstract
When faced with proteotoxic stress, cells mount adaptive responses to eliminate aberrant proteins. Adaptive responses increase the expression of protein folding and degradation factors to enhance the cellular quality control machinery. However, it is unclear whether and how this augmented machinery acquires new activities during stress. Here, we uncover a regulatory cascade in budding yeast that consists of the hydrophilin protein Roq1/Yjl144w, the HtrA-type protease Ynm3/Nma111, and the ubiquitin ligase Ubr1. Various stresses stimulate ROQ1 transcription. The Roq1 protein is cleaved by Ynm3. Cleaved Roq1 interacts with Ubr1, transforming its substrate specificity. Altered substrate recognition by Ubr1 accelerates proteasomal degradation of misfolded as well as native proteins at the endoplasmic reticulum membrane and in the cytosol. We term this pathway stress-induced homeostatically regulated protein degradation (SHRED) and propose that it promotes physiological adaptation by reprogramming a key component of the quality control machinery.
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Affiliation(s)
- Tamas Szoradi
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, 69120 Heidelberg, Germany
| | - Katharina Schaeff
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, 69120 Heidelberg, Germany
| | - Enrique M Garcia-Rivera
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Daniel N Itzhak
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Rolf M Schmidt
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, 69120 Heidelberg, Germany
| | - Peter W Bircham
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, 69120 Heidelberg, Germany
| | - Kevin Leiss
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, 69120 Heidelberg, Germany
| | - Juan Diaz-Miyar
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, 69120 Heidelberg, Germany
| | - Vivian K Chen
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Dale Muzzey
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Georg H H Borner
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Sebastian Schuck
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance and CellNetworks Cluster of Excellence, 69120 Heidelberg, Germany.
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10
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Sun Y, Chao JR, Xu W, Pourpak A, Boyd K, Moshiach S, Qi GY, Fu A, Shao HR, Pounds S, Morris SW. MLF1 is a proapoptotic antagonist of HOP complex-mediated survival. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:719-727. [PMID: 28137643 DOI: 10.1016/j.bbamcr.2017.01.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 01/16/2017] [Accepted: 01/26/2017] [Indexed: 10/20/2022]
Abstract
In the HAX1/HtrA2-OMI/PARL (HOP) mitochondrial protein complex, anti-apoptotic signals are generated by cleavage and activation of the serine protease HtrA2/OMI by the rhomboid protease PARL upon recruitment of both proteases to inner mitochondrial membrane protein HAX1 (HS1-associated protein X-1). Here we report the negative regulation of the HOP complex by human leukemia-associated myeloid leukemia factor 1 (MLF1). We demonstrate that MLF1 physically and functionally associates with HAX1 and HtrA2. Increased interaction of MLF1 with HAX1 and HtrA2 displaces HtrA2 from the HOP complex and inhibits HtrA2 cleavage and activation, resulting in the apoptotic cell death. Conversely, over-expressed HAX1 neutralizes MLF1's effect and inhibits MLF1-induced apoptosis. Importantly, Mlf1 deletion reverses B- and T-cell lymphopenia and significantly ameliorates the progressive striatal and cerebellar neurodegeneration observed in Hax1-/- mice, with a doubling of the lifespan of Mlf1-/-/Hax1-/- animals compared to Hax1-/- animals. Collectively, these data indicate that MLF1 serves as a proapoptotic antagonist that interacts with the HOP mitochondrial complex to modulate cell survival.
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Affiliation(s)
- Yi Sun
- Department of Oncology, ShiJiaZhuangShi First Hospital, 36 FanXiLu, ShiJiaZhuangShi, Hebei 050011, PR China; Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA.
| | - Jyh-Rong Chao
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA
| | - Wu Xu
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, LA 70504, USA
| | - Alan Pourpak
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA
| | - Kelli Boyd
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA
| | - Simon Moshiach
- Department of Genetics, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA
| | - Guo-Yan Qi
- Department of Oncology, ShiJiaZhuangShi First Hospital, 36 FanXiLu, ShiJiaZhuangShi, Hebei 050011, PR China
| | - Amina Fu
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA
| | - Hua-Rong Shao
- Department of Orthopaedics, ShiJiaZhuangShi First Hospital, 36 FanXiLu, ShiJiaZhuangShi, Hebei 050011, PR China
| | - Stanley Pounds
- Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA
| | - Stephan W Morris
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA
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Pruefer FG, Lizarraga F, Maldonado V, Melendez-Zajgla J. Participation of Omi Htra2 Serine-Protease Activity in the Apoptosis Induced by Cisplatin on SW480 Colon Cancer Cells. J Chemother 2013; 20:348-54. [DOI: 10.1179/joc.2008.20.3.348] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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12
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Goo HG, Jung MK, Han SS, Rhim H, Kang S. HtrA2/Omi deficiency causes damage and mutation of mitochondrial DNA. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1866-75. [PMID: 23542127 DOI: 10.1016/j.bbamcr.2013.03.016] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 03/18/2013] [Accepted: 03/20/2013] [Indexed: 10/27/2022]
Abstract
High-temperature requirement protein A2 (HtrA2), a serine protease, localizes in the mitochondria and has diverse roles, including maintenance of mitochondrial homeostasis and regulation of cellular apoptosis. HtrA2 (also known as Omi) is associated with many neurodegenerative diseases, including Parkinson disease. By employing agarose gel electrophoresis, a fluorescent dye, PicoGreen, intercalation into mtDNA, and long-range PCR (LR-PCR), we showed that mitochondrial DNA conformational stability is related to HtrA2. Nicked forms of mtDNA were produced through reactive oxygen species generated by loss of HtrA2 protease activity, and mtDNA mutations frequently occurred in HtrA2(-/-) cells, but not in HtrA2(+/+) cells. We found conformational changes in mtDNA from the brain tissue of mnd2 mutant mice that lack the serine protease activity of HtrA2. Overexpression of HtrA2 with protease activity targeted to mitochondria only was able to restore mtDNA conformational stability in HtrA2(-/-) MEF cells. Nuclear-encoded mtDNA repair genes, including POLG2, Twinkle, and APTX1, were significantly upregulated in HtrA2(-/-) cells. Electron microscopy showed that mitochondrial morphology itself was not affected, even in HtrA2(-/-) cells. Our results demonstrate that HtrA2 deficiency causes mtDNA damage through ROS generation and mutation, which may lead to mitochondrial dysfunction and consequent triggering of cell death in aging cells.
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Affiliation(s)
- Hui-Gwan Goo
- Division of Life Sciences, Korea University, Seoul, Republic of Korea
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13
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Zurawa-Janicka D, Kobiela J, Galczynska N, Stefaniak T, Lipinska B, Lachinski A, Skorko-Glonek J, Narkiewicz J, Proczko-Markuszewska M, Sledzinski Z. Changes in expression of human serine protease HtrA1, HtrA2 and HtrA3 genes in benign and malignant thyroid tumors. Oncol Rep 2012; 28:1838-44. [PMID: 22923201 DOI: 10.3892/or.2012.1988] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 05/31/2012] [Indexed: 11/06/2022] Open
Abstract
Human HtrA proteins are serine proteases involved in essential physiological processes. HtrA1 and HtrA3 function as tumor suppressors and inhibitors of the TGF-β signaling pathway. HtrA2 regulates mitochondrial homeostasis and plays a pivotal role in the induction of apoptosis. The aim of the study was to determine whether the HtrA proteins are involved in thyroid carcinogenesis. We used the immunoblotting technique to estimate protein levels of HtrA1, HtrA2, long and short variants of HtrA3 (HtrA3-L and HtrA3-S) and TGF-β1 in tissues of benign and malignant thyroid lesions, and control groups. We found that the levels of HtrA2 and HtrA3-S were higher in thyroid malignant tumors compared to normal tissues and benign tumors. The HtrA3-L level was increased in malignant tumor tissues compared to benign tumor tissues and control tissues from patients with benign lesions, and elevated in normal tissues from patients with thyroid carcinoma compared to normal tissues from patients with benign lesions. We also compared levels of HtrA proteins in follicular thyroid carcinoma (FTC) and papillary thyroid carcinoma (PTC) and found that these types of carcinoma differed in the expression of HtrA3-S and HtrA1. These results indicate the implication of HtrA proteins in thyroid carcinogenesis suggest that HtrA3 variants may play different roles in cancer development, and that the increased HtrA3-L levels in thyroid tissue could be correlated with the development of malignant lesions. The TGF-β1 levels in tumor tissues were not significantly altered compared to control tissues.
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14
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HtrA1 is a novel antagonist controlling fibroblast growth factor (FGF) signaling via cleavage of FGF8. Mol Cell Biol 2012; 32:4482-92. [PMID: 22949504 DOI: 10.1128/mcb.00872-12] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Accumulating evidence suggests that HtrA1 (high-temperature requirement A1) is involved in modulating crucial cellular processes and implicated in life-threatening diseases, such as cancer and neuropathological disorders; however, the exact functions of this protease in vivo remain unknown. Here, we show that loss of HtrA1 function increases fibroblast growth factor 8 (FGF8) mRNA levels and triggers activation of FGF signaling, resulting in dorsalization in zebrafish embryos. Notably, HtrA1 directly cleaves FGF8 in the extracellular region, and this cleavage results in decreased activation of FGF signaling, which is essential for many physiological processes. Therefore, HtrA1 is indispensable for dorsoventral patterning in early zebrafish embryogenesis and serves as a key upstream regulator of FGF signaling through the control of FGF levels. Furthermore, this study offers insight into new strategies to control human diseases associated with HtrA1 and FGF signaling.
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15
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Cytoplasmic expression, antibody production, and characterization of the novel zinc finger protein 637. Appl Microbiol Biotechnol 2012; 97:741-9. [PMID: 22733115 DOI: 10.1007/s00253-012-4235-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 06/07/2012] [Accepted: 06/08/2012] [Indexed: 02/05/2023]
Abstract
Zinc finger protein 637 (zfp637), belonging to the Kruppel-like protein family, comprises one atypical C(2)H(2) and six consecutive typical zinc finger motifs. Based on the structural characterization of zfp637 and its location in the cell nucleus, we predict that zfp637 might function as a DNA-binding protein to regulate gene transcription. However, the absence of both a purified zfp637 protein and any commercial antibody for detecting it in cells and tissues has limited functional studies of zfp637 to date. Here, we developed and optimized an expression system by fusing zfp637 with glutathione S-transferase (GST) to achieve a maximal yield of soluble GST-zfp637 fusion protein in Escherichia coli BL21(DE3) cells. The yield was about 10 mg/l of the original bacterial culture. The recombinant GST-zfp637 fusion protein was purified and used for polyclonal antibody production in rabbits. In addition, we developed a method to remove the anti-GST antibody component and obtained a highly purified anti-zfp637 antibody, as demonstrated by an enzyme-linked immunosorbent assay. Western blotting showed that the anti-zfp637 antibody recognized not only the recombinant zfp637 protein but also endogenous zfp637 in several cell lines. The protein was localized mainly in the cell nucleus by immunofluorescence and immunohistochemistry. The expression levels of zfp637 mRNA and protein were significantly increased in NIH3T3 cells treated with 200 μM of H(2)O(2) in a time-dependent manner. The recombinant GST-zfp637 fusion protein and our purified anti-zfp637 antibody will help in elucidating the function of zfp637.
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16
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Zheng ZL, Tan LZ, Yu YP, Michalopoulos G, Luo JH. Interaction of CSR1 with XIAP reverses inhibition of caspases and accelerates cell death. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 181:463-71. [PMID: 22683311 DOI: 10.1016/j.ajpath.2012.04.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 03/29/2012] [Accepted: 04/12/2012] [Indexed: 11/29/2022]
Abstract
Cellular Stress Response 1 (CSR1) is a tumor suppressor gene that is located at 8p21, a region that is frequently deleted in prostate cancer as well as a variety of human malignancies. Previous studies have indicated that the expression of CSR1 induces cell death. In this study, we found that CSR1 interacts with X-linked Inhibitor of Apoptosis Protein (XIAP), using yeast two-hybrid screening analyses. XIAP overexpression has been found in many human cancers, and forced expression of XIAP blocks apoptosis. Both in vitro and in vivo analyses indicated that the C-terminus of CSR1 binds XIAP with high affinity. Through a series of in vitro recombinant protein-binding analyses, the XIAP-binding motif in CSR1 was determined to include amino acids 513 to 572. Targeted knock-down of XIAP enhanced CSR1-induced cell death, while overexpression of XIAP antagonized CSR1 activity. The binding of CSR1 with XIAP enhanced caspase-9 and caspase-3 protease activities, and CSR1-induced cell death was dramatically reduced on expression of a mutant CSR1 that does not bind XIAP. However, a XIAP mutant that does not interact with caspase-9 had no impact on CSR1-induced cell death. These results suggest that cell death is induced when CSR1 binds XIAP, preventing the interaction of XIAP with caspases. Thus, this study may have elucidated a novel mechanism by which tumor suppressors induce cell death.
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Affiliation(s)
- Zhong-Liang Zheng
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA
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17
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Park DW, Kim SS, Nam MK, Kim GY, Kim J, Rhim H. Improved recovery of active GST-fusion proteins from insoluble aggregates: solubilization and purification conditions using PKM2 and HtrA2 as model proteins. BMB Rep 2011; 44:279-84. [PMID: 21524355 DOI: 10.5483/bmbrep.2011.44.4.279] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The glutathione S-transferase (GST) system is useful for increasing protein solubility and purifying soluble GST fusion proteins. However, purifying half of the GST fusion proteins is still difficult, because they are virtually insoluble under non-denaturing conditions. To optimize a simple and rapid purification condition for GST-pyruvate kinase muscle 2 (GST-PKM2) protein, we used 1% sarkosyl for lysis and a 1:200 ratio of sarkosyl to Triton X-100 (S-T) for purification. We purified the GST-PKM2 protein with a high yield, approximately 5 mg/L culture, which was 33 times higher than that prepared using a conventional method. Notably, the GST-high-temperature requirement A2 (GST-HtrA2) protein, used as a model protein for functional activity, fully maintained its proteolytic activity, even when purified under our S-T condition. This method may be useful to apply to other biologically important proteins that become highly insoluble in the prokaryotic expression system.
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Affiliation(s)
- Dae-Wook Park
- Department of Biomedical Sciences, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea
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18
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Abstract
Wilms' tumour is a paediatric malignancy of the kidneys and is one of the most common solid childhood cancers. The Wilms' tumour 1 protein (WT1) is a transcription factor that can either activate or repress genes involved in growth, apoptosis and differentiation. It is frequently mutated or aberrantly expressed in Wilms' tumour, where the wild type protein would normally act as a tumour suppressor. Several studies, however, have found that wild type WT1 acts as an oncogene in adult tumours, primarily through the inhibition of apoptosis. The expression of WT1 correlates with the aggressiveness of several adult cancers, and its continued expression following treatment is indicative of a poor outcome.We recently found that the treatment of tumour cell lines with cytotoxic drugs leads to the cleavage of WT1 by the serine protease HtrA2. HtrA2 binds to a specific region of WT1, the suppression domain, and then cleaves WT1 at multiple sites. The HtrA2-mediated proteolysis of WT1 leads to its removal from gene promoter regions and changes in gene expression. Cleavage of WT1 by HtrA2 enhances apoptosis. This event is advantageous to the treatment of adult tumours where WT1 acts as an oncogene. However, when WT1 is acting as a tumour suppressor in paediatric malignancies, proteolysis by HtrA2 would be antagonistic to therapy.
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Affiliation(s)
- Jörg Hartkamp
- Faculty of Life Sciences, The Michael Smith Building, University of Manchester, Manchester, UK
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19
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Westerlund M, Behbahani H, Gellhaar S, Forsell C, Belin AC, Anvret A, Zettergren A, Nissbrandt H, Lind C, Sydow O, Graff C, Olson L, Ankarcrona M, Galter D. Altered enzymatic activity and allele frequency of OMI/HTRA2 in Alzheimer's disease. FASEB J 2010; 25:1345-52. [PMID: 21163861 DOI: 10.1096/fj.10-163402] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The serine-protease OMI/HTRA2, required for several cellular processes, including mitochondrial function, autophagy, chaperone activity, and apoptosis, has been implicated in the pathogenesis of both Alzheimer's disease (AD) and Parkinson's disease (PD). Western blot quantification of OMI/HTRA2 in frontal cortex of patients with AD (n=10) and control subjects (n=10) in two separate materials indicated reduced processed (active, 35 kDa) OMI/HTRA2 levels, whereas unprocessed (50 kDa) enzyme levels were not significantly different between the groups. Interestingly, the specific protease activity of OMI/HTRA2 was found to be significantly increased in patients with AD (n=10) compared to matched control subjects (n=10) in frontal cortex in two separate materials. Comparison of OMI/HTRA2 mRNA levels in frontal cortex and hippocampus, two brain areas particularly affected by AD, indicated similar levels in patients with AD (n=10) and matched control subjects (n=10). In addition, we analyzed the occurrence of the OMI/HTRA2 variants A141S and G399S in Swedish case-control materials for AD and PD and found a weak association of A141S with AD, but not with PD. In conclusion, our genetic, histological, and biochemical findings give further support to an involvement of OMI/HTRA2 in the pathology of AD; however, further studies are needed to clarify the role of this gene in neurodegeneration.
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Affiliation(s)
- Marie Westerlund
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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20
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Zurawa-Janicka D, Skorko-Glonek J, Lipinska B. HtrA proteins as targets in therapy of cancer and other diseases. Expert Opin Ther Targets 2010; 14:665-79. [PMID: 20469960 DOI: 10.1517/14728222.2010.487867] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD The HtrA family proteins are serine proteases that are involved in important physiological processes, including maintenance of mitochondrial homeostasis, apoptosis and cell signaling. They are involved in the development and progression of several pathological processes such as cancer, neurodegenerative disorders and arthritic diseases. AREAS COVERED IN THIS REVIEW We present characteristics of the human HtrA1, HtrA2 and HtrA3 proteins, with the stress on their function in apoptosis and in the diseases. We describe regulation of the HtrAs' proteolytic activity, focusing on allosteric interactions of ligands/substrates with the PDZ domains, and make suggestions on how the HtrA proteolytic activity could be modified. Literature cited covers years 1996 - 2010. WHAT THE READER WILL GAIN An overview of the HtrAs' function/regulation and involvement in diseases (cancer, neurodegenerative disorders, arthritis), and ideas how modulation of their proteolytic activity could be used in therapies. TAKE HOME MESSAGE HtrA2 is the best target for cancer drug development. An increase in the HtrAs' proteolytic activity could be beneficial in cancer treatment, by stimulation of apoptosis, anoikis or necrosis of cancer cells, or by modulation of the TGF-beta signaling cascade; modulation of HtrA activity could be helpful in therapy of neurodegenerative diseases and arthritis.
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21
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Beleford D, Rattan R, Chien J, Shridhar V. High temperature requirement A3 (HtrA3) promotes etoposide- and cisplatin-induced cytotoxicity in lung cancer cell lines. J Biol Chem 2010; 285:12011-27. [PMID: 20154083 DOI: 10.1074/jbc.m109.097790] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lung cancer is the leading cause of cancer-related deaths worldwide. Here we show for the first time that HtrA3 is a mitochondrial stress-response factor that promotes cytotoxicity to etoposide and cisplatin in lung cancer cell lines. Exogenous expression of wild type HtrA3 domain variants significantly attenuated cell survival with etoposide and cisplatin treatment in lung cancer cell lines H157 and A549 compared with expression of protease inactive mutants (S305A) or vector control. Conversely, HtrA3 suppression promoted cell survival with etoposide and cisplatin treatment in lung cancer cell lines Hop62 and HCC827. Survival was attenuated by re-expression of wild type HtrA3 variants during treatment but not by protease inactive mutants or vector control. HtrA3 also co-fractionated and co-localized with mitochondrial markers with both endogenous and exogenous expression in normal lung and lung cancer cell lines but was translocated from mitochondria following etoposide treatment. Moreover, HtrA3 translocation from mitochondria correlated with an increase in cell death that was attenuated by either HtrA3 suppression or Bcl-2 overexpression. Taken together, these results suggest that HtrA3 may be a previously uncharacterized mitochondrial cell death effector whose serine protease function may be crucial to modulating etoposide- and cisplatin-induced cytotoxicity in lung cancer cell lines.
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Affiliation(s)
- Daniah Beleford
- Department of Experimental Pathology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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22
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Johnson F, Kaplitt MG. Novel mitochondrial substrates of omi indicate a new regulatory role in neurodegenerative disorders. PLoS One 2009; 4:e7100. [PMID: 19763263 PMCID: PMC2740829 DOI: 10.1371/journal.pone.0007100] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Accepted: 08/19/2009] [Indexed: 12/30/2022] Open
Abstract
The mitochondrial protease OMI (also known as HtrA2) has been implicated in Parkinson's Disease (PD) and deletion or protease domain point mutations have shown profound neuropathologies in mice. A beneficial role by OMI, in preserving cell viability, is assumed to occur via the avoidance of dysfunctional protein turnover. However relatively few substrates for mitochondrial Omi are known. Here we report our identification of three novel mitochondrial substrates that impact metabolism and ATP production. Using a dual proteomic approach we have identified three interactors based upon ability to bind to OMI, and/or to persist in the proteome after OMI activity has been selectively inhibited. One candidate, the chaperone HSPA8, was common to each independent study. Two others (PDHB subunit and IDH3A subunit) did not appear to bind to OMI, however persisted in the mito-proteome when OMI was inhibited. Pyruvate dehydrogenase (PDH) and isocitrate dehydrogenase (IDH) are two key Kreb's cycle enzymes that catalyse oxidative decarboxylation control points in mitochondrial respiration. We verified both PDHB and IDH3A co-immunoprecipitate with HSPA8 and after elution, were degraded by recombinant HtrA2 in vitro. Additionally our gene expression studies, using rotenone (an inhibitor of Complex I) showed Omi expression was silenced when pdhb and idh3a were increased when a sub-lethal dose was applied. However higher dose treatment caused increased Omi expression and decreased levels of pdhb and idh3a transcripts. This implicates mitochondrial OMI in a novel mechanism relating to metabolism.
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Affiliation(s)
- Felicity Johnson
- Department of Neurological Surgery, Cornell University, Weill Medical College, New York, New York, USA.
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23
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McCormick AL, Roback L, Mocarski ES. HtrA2/Omi terminates cytomegalovirus infection and is controlled by the viral mitochondrial inhibitor of apoptosis (vMIA). PLoS Pathog 2008; 4:e1000063. [PMID: 18769594 PMCID: PMC2528007 DOI: 10.1371/journal.ppat.1000063] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Accepted: 04/10/2008] [Indexed: 02/07/2023] Open
Abstract
Viruses encode suppressors of cell death to block intrinsic and extrinsic host-initiated death pathways that reduce viral yield as well as control the termination of infection. Cytomegalovirus (CMV) infection terminates by a caspase-independent cell fragmentation process after an extended period of continuous virus production. The viral mitochondria-localized inhibitor of apoptosis (vMIA; a product of the UL37x1 gene) controls this fragmentation process. UL37x1 mutant virus-infected cells fragment three to four days earlier than cells infected with wt virus. Here, we demonstrate that infected cell death is dependent on serine proteases. We identify mitochondrial serine protease HtrA2/Omi as the initiator of this caspase-independent death pathway. Infected fibroblasts develop susceptibility to death as levels of mitochondria-resident HtrA2/Omi protease increase. Cell death is suppressed by the serine protease inhibitor TLCK as well as by the HtrA2-specific inhibitor UCF-101. Experimental overexpression of HtrA2/Omi, but not a catalytic site mutant of the enzyme, sensitizes infected cells to death that can be blocked by vMIA or protease inhibitors. Uninfected cells are completely resistant to HtrA2/Omi induced death. Thus, in addition to suppression of apoptosis and autophagy, vMIA naturally controls a novel serine protease-dependent CMV-infected cell-specific programmed cell death (cmvPCD) pathway that terminates the CMV replication cycle. Cellular suicide is an effective host defense mechanism to control viral infection. Host cells encode proteins that induce infected cell death while viruses encode proteins that prevent death and facilitate viral replication. Human cytomegalovirus encodes vMIA to suppress host-initiated death pathways. Cytomegalovirus infection is controlled by the evolutionarily ancient mitochondrial serine protease, HtrA2/Omi. HtrA2/Omi levels rise dramatically within mitochondria at late times during viral infection, eventually overcoming viral control of a cell death pathway that is dependent on this serine protease and independent of the well-studied apoptotic cell death pathway that conventionally depends upon a class of proteases called caspases. vMIA naturally counteracts HtrA2/Omi-dependent cell death and allows infected cells to survive and produce virus for several days. The natural inhibitory role of vMIA can be overwhelmed by overexpression of HtrA2/Omi in virus-infected cells, but uninfected cells are insensitive to HtrA2/Omi-induced death. The broad distribution of HtrA2/Omi within mammalian host species suggests this may represent an ancient antiviral response or a process of viral detente that establishes the timing of infection. Either way, the success of cytomegalovirus rests in the balance between cell death initiation and the viral cell death suppressor vMIA.
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Affiliation(s)
- A Louise McCormick
- Department of Microbiology and Immunology and Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia, United States of America.
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24
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Vande Walle L, Lamkanfi M, Vandenabeele P. The mitochondrial serine protease HtrA2/Omi: an overview. Cell Death Differ 2008; 15:453-60. [PMID: 18174901 DOI: 10.1038/sj.cdd.4402291] [Citation(s) in RCA: 233] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The HtrA family refers to a group of related oligomeric serine proteases that combine a trypsin-like protease domain with at least one PDZ interaction domain. Mammals encode four HtrA proteases, named HtrA1-4. The protease activity of the HtrA member HtrA2/Omi is required for mitochondrial homeostasis in mice and humans and inactivating mutations associated with neurodegenerative disorders such as Parkinson's disease. Moreover, HtrA2/Omi is released in the cytosol, where it contributes to apoptosis through both caspase-dependent and -independent pathways. Here, we review the current knowledge of HtrA2/Omi biology and discuss the signaling pathways that underlie its mitochondrial and apoptotic functions from an evolutionary perspective.
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Affiliation(s)
- L Vande Walle
- Department for Molecular Biomedical Research, Unit for Molecular Signalling and Cell Death, VIB, Ghent, Belgium
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25
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A simple and rapid strategy for the molecular cloning and monitoring of mouse HtrA2 serine protease. Biotechnol Lett 2007; 30:397-403. [DOI: 10.1007/s10529-007-9556-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 09/10/2007] [Accepted: 09/18/2007] [Indexed: 10/22/2022]
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26
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Griparic L, Kanazawa T, van der Bliek AM. Regulation of the mitochondrial dynamin-like protein Opa1 by proteolytic cleavage. ACTA ACUST UNITED AC 2007; 178:757-64. [PMID: 17709430 PMCID: PMC2064541 DOI: 10.1083/jcb.200704112] [Citation(s) in RCA: 362] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The dynamin-related protein Opa1 is localized to the mitochondrial intermembrane space, where it facilitates fusion between mitochondria. Apoptosis causes Opa1 release into the cytosol and causes mitochondria to fragment. Loss of mitochondrial membrane potential also causes mitochondrial fragmentation but not Opa1 release into the cytosol. Both conditions induce the proteolytic cleavage of Opa1, suggesting that mitochondrial fragmentation is triggered by Opa1 inactivation. The opposite effect was observed with knockdown of the mitochondrial intermembrane space protease Yme1. Knockdown of Yme1 prevents the constitutive cleavage of a subset of Opa1 splice variants but does not affect carbonyl cyanide m-chlorophenyl hydrazone or apoptosis-induced cleavage. Knockdown of Yme1 also increases mitochondrial connectivity, but this effect is independent of Opa1 because it also occurs in Opa1 knockdown cells. We conclude that Yme1 constitutively regulates a subset of Opa1 isoforms and an unknown mitochondrial morphology protein, whereas the loss of membrane potential induces the further proteolysis of Opa1.
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Affiliation(s)
- Lorena Griparic
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
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27
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Yang L, Sun M, Sun XM, Cheng GZ, Nicosia SV, Cheng JQ. Akt Attenuation of the Serine Protease Activity of HtrA2/Omi through Phosphorylation of Serine 212. J Biol Chem 2007; 282:10981-7. [PMID: 17311912 DOI: 10.1074/jbc.m700445200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The serine protease HtrA2/Omi is released from the mitochondria into the cytosol following apoptosis stimuli, leading to the programmed cell death in caspase-dependent and -independent manners. The function of HtrA2/Omi closely relates to its protease activity, which is required for cleavage of its substrate such as the members of the X-linked inhibitor of apoptotic protein family. However, the regulation of HtrA2/Omi by signaling molecule has not been documented. Here we report that serine/threonine kinases Akt1 and Akt2 phosphorylate mitochondria-released HtrA2/Omi on serine 212 in vivo and in vitro, which results in attenuation of its serine protease activity and pro-apoptotic function. Abolishing HtrA2/Omi phosphorylation by Akt through mutation of serine 212 to alanine (HtrA2/Omi-S212A) retains its serine protease activity and induces more apoptosis as compared with wild-type HtrA2/Omi. Conversely, HtrA2/Omi-S212D, a mutant mimicking phosphorylation, lost the protease activity and failed to induce the programmed cell death. Furthermore, the phosphorylated HtrA2/Omi fails to cleave X-linked inhibitor of apoptotic protein without interfering with their complex formation. In addition, Akt inhibits the release of HtrA2/Omi from the mitochondria into the cytoplasm in response to cisplatin treatment. These data reveal for the first time that HtrA2/Omi is directly regulated by Akt and provide a mechanism by which Akt induces cell survival at post-mitochondrial level.
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Affiliation(s)
- Lin Yang
- Department of Pathology and Cell Biology and Molecular Oncology Program, H. Lee Moffitt Cancer Center and College of Medicine, University of South Florida, Tampa, Florida 33612, USA
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28
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Straszewski-Chavez SL, Visintin IP, Karassina N, Los G, Liston P, Halaban R, Fadiel A, Mor G. XAF1 mediates tumor necrosis factor-alpha-induced apoptosis and X-linked inhibitor of apoptosis cleavage by acting through the mitochondrial pathway. J Biol Chem 2007; 282:13059-72. [PMID: 17329253 DOI: 10.1074/jbc.m609038200] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Tumor necrosis factor-alpha (TNF-alpha) and Fas ligand induce apoptosis by interacting with their corresponding membrane-bound death receptors and activating caspases. Since both systems share several components of the intracellular apoptotic cascade and are expressed by first trimester trophoblasts, it is unknown how these cells remain resistant to Fas ligand while sensitive to TNF-alpha. XAF1 (X-linked inhibitor of apoptosis (XIAP)-associated factor 1) is a proapoptotic protein that antagonizes the caspase-inhibitory activity of XIAP. Here, we demonstrated that XAF1 functions as an alternative pathway for TNF-alpha-induced apoptosis by translocating to the mitochondria and promoting XIAP inactivation. In addition, we showed that the overexpression of XAF1 sensitized first trimester trophoblast cells to Fas-mediated apoptosis. Furthermore, we also determined that the differential expression of XAF1 in first and third trimester trophoblast cells was due to changes in XAF1 gene methylation. Our results establish a novel regulatory pathway controlling trophoblast cell survival and provide a molecular mechanism to explain trophoblast sensitivity to TNF-alpha and the increased number of apoptotic trophoblast cells observed near term. Aberrant XAF1 expression and/or localization may have consequences for normal pregnancy outcome.
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Affiliation(s)
- Shawn L Straszewski-Chavez
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA
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Ryter SW, Kim HP, Hoetzel A, Park JW, Nakahira K, Wang X, Choi AMK. Mechanisms of cell death in oxidative stress. Antioxid Redox Signal 2007; 9:49-89. [PMID: 17115887 DOI: 10.1089/ars.2007.9.49] [Citation(s) in RCA: 876] [Impact Index Per Article: 51.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Reactive oxygen or nitrogen species (ROS/RNS) generated endogenously or in response to environmental stress have long been implicated in tissue injury in the context of a variety of disease states. ROS/RNS can cause cell death by nonphysiological (necrotic) or regulated pathways (apoptotic). The mechanisms by which ROS/RNS cause or regulate apoptosis typically include receptor activation, caspase activation, Bcl-2 family proteins, and mitochondrial dysfunction. Various protein kinase activities, including mitogen-activated protein kinases, protein kinases-B/C, inhibitor-of-I-kappaB kinases, and their corresponding phosphatases modulate the apoptotic program depending on cellular context. Recently, lipid-derived mediators have emerged as potential intermediates in the apoptosis pathway triggered by oxidants. Cell death mechanisms have been studied across a broad spectrum of models of oxidative stress, including H2O2, nitric oxide and derivatives, endotoxin-induced inflammation, photodynamic therapy, ultraviolet-A and ionizing radiations, and cigarette smoke. Additionally ROS generated in the lung and other organs as the result of high oxygen therapy or ischemia/reperfusion can stimulate cell death pathways associated with tissue damage. Cells have evolved numerous survival pathways to counter proapoptotic stimuli, which include activation of stress-related protein responses. Among these, the heme oxygenase-1/carbon monoxide system has emerged as a major intracellular antiapoptotic mechanism.
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Affiliation(s)
- Stefan W Ryter
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, The University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA.
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Zhang M, Liu H, Tian Z, Griffith BN, Ji M, Li QQ. Gossypol induces apoptosis in human PC-3 prostate cancer cells by modulating caspase-dependent and caspase-independent cell death pathways. Life Sci 2006; 80:767-74. [PMID: 17156797 DOI: 10.1016/j.lfs.2006.11.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2006] [Revised: 10/18/2006] [Accepted: 11/03/2006] [Indexed: 12/20/2022]
Abstract
The rate of gossypol-induced apoptosis does not correlate very well with the same dose of gossypol-induced cell growth inhibition, indicating an anti-proliferative effect of gossypol. Using a co-immunoprecipitation assay, it was observed that the level of Bcl-X(L) protein bound to Bax was clearly lower than that of Bcl-2 protein at 5 micro M of gossypol treatment, and the level of Bim protein bound to Bcl-X(L) was lowered at 20 micro M of gossypol treatment for 24 h, implicating that gossypol inhibits the heterodimerization of Bcl-X(L) with Bax and Bim. Gossypol-induced apoptosis is partly suppressed by as low as 0.5 micro M, but not abolished by as high as 50 micro M of a broad range caspase inhibitor, Z-VAD-FMK, suggesting that gossypol-induced apoptosis is both caspase-dependent and -independent. Furthermore, the release of apoptosis inducing factor (AIF), which triggers caspase-independent apoptosis, from mitochondria to cytosol was observed in PC-3 cells exposed to gossypol treatment. In conclusion, gossypol inhibits the proliferation and induces apoptosis in PC-3 cells. Gossypol-induced apoptosis is, at least, through inhibiting the heterodimerization of Bcl-X(L)/Bcl-2 with pro-apoptosis molecules, followed by a caspase-dependent and -independent process which involves the release of AIF from the mitochondria to cytosol.
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Affiliation(s)
- Manchao Zhang
- Department of Biochemistry and Molecular Pharmacology, West Virginia University, Morgantown, WV 26506, USA.
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Park HJ, Kim SS, Seong YM, Kim KH, Goo HG, Yoon EJ, Min DS, Kang S, Rhim H. Beta-amyloid precursor protein is a direct cleavage target of HtrA2 serine protease. Implications for the physiological function of HtrA2 in the mitochondria. J Biol Chem 2006; 281:34277-87. [PMID: 16968707 DOI: 10.1074/jbc.m603443200] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The processing and metabolism of amyloid precursor protein (APP) is a major interest in Alzheimer disease (AD) research, because not only amyloid beta (Abeta) peptide, but also cellular or mitochondrial APP are intimately involved in cellular dysfunction and AD pathogenesis. Here we demonstrate that APP is directly and efficiently cleaved by the HtrA2 serine protease in vitro and in vivo. Using several APP mutants and N-terminal amino acid sequencing, we identified that the HtrA2-mediated APP cleavage product is the C161 fragment encompassing amino acids 535-695 of APP695. The immunofluorescence and subcellular fractionation studies indicate that APP is partly colocalized with HtrA2 in the mitochondria where HtrA2 can cleave APP under normal conditions. The HtrA2-cleaved C161 fragment was detected in the cytosolic fraction; therefore, we postulate that the C161 fragment is released into the cytosol after cleavage of APP by HtrA2. Interestingly, the level of C161 was remarkably decreased in motor neuron degeneration (mnd2) mice in which the serine protease activity of HtrA2 was greatly reduced. These results show that the protease activity of HtrA2 is essential for the production of C161 and that processing of APP into C161 is a natural event occurring under normal physiological conditions. Our study suggests that the direct cleavage of mitochondrial APP by HtrA2 may prevent mitochondrial dysfunction caused by accumulation of APP and that the regulation of HtrA2 protease activity may be a therapeutic target in AD.
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Affiliation(s)
- Hyo-Jin Park
- School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, South Korea
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Han J, Goldstein LA, Gastman BR, Rabinowich H. Interrelated roles for Mcl-1 and BIM in regulation of TRAIL-mediated mitochondrial apoptosis. J Biol Chem 2006; 281:10153-63. [PMID: 16478725 DOI: 10.1074/jbc.m510349200] [Citation(s) in RCA: 151] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The current study demonstrates a novel cross-talk mechanism between the TRAIL receptor death signaling pathway and the mitochondria. This newly identified pathway is regulated at the mitochondrial outer membrane by a complex between the prosurvival Bcl-2 member, Mcl-1 and the BH3-only protein, Bim. Under non-apoptotic conditions, Bim is sequestered by Mcl-1. Direct degradation of Mcl-1 by TRAIL-activated caspase-8 or caspase-3 produces Mcl-1-free Bim that mediates a Bax-dependent apoptotic cascade. Using Mcl-1 or Bim RNAi, we demonstrate that a loss in Mcl-1 expression significantly enhances the mitochondrial apoptotic response to TRAIL that is now mediated by freed Bim. Whereas overexpression of Mcl-1 contributes to the preservation of the mitochondrial membrane potential, Mcl-1 knockdown facilitates the Bim-mediated dissipation of this potential. Loss of Mcl-1 contributes to an increased level of caspase activity downstream of the mitochondrial response to TRAIL. Furthermore, the Mcl-1 expression level at the mitochondrial outer membrane determines the release efficiency for the apoptogenic proteins cytochrome c, Smac, and HtrA2 in response to Bim. These are the first findings to demonstrate the involvement of Bim in the TRAIL-mediated mitochondrial cascade. They also suggest that Mcl-1 may serve as a direct substrate for TRAIL-activated caspases implying the existence of a novel TRAIL/caspase-8/Mcl-1/Bim communication mechanism between the extrinsic and the intrinsic apoptotic pathways.
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Affiliation(s)
- Jie Han
- Department of Pathology, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
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Burri L, Strahm Y, Hawkins CJ, Gentle IE, Puryer MA, Verhagen A, Callus B, Vaux D, Lithgow T. Mature DIABLO/Smac is produced by the IMP protease complex on the mitochondrial inner membrane. Mol Biol Cell 2005; 16:2926-33. [PMID: 15814844 PMCID: PMC1142436 DOI: 10.1091/mbc.e04-12-1086] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
DIABLO/Smac is a mitochondrial protein that can promote apoptosis by promoting the release and activation of caspases. To do so, DIABLO/Smac must first be processed by a mitochondrial protease and then released into the cytosol, and we show this in an intact cellular system. We propose that the precursor form of DIABLO/Smac enters the mitochondria through a stop-transfer pathway and is processed to its active form by the inner membrane peptidase (IMP) complex. Catalytic subunits of the mammalian IMP complex were identified based on sequence conservation and functional complementation, and the novel sequence motif RX(5)P in Imp1 and NX(5)S in Imp2 distinguish the two catalytic subunits. DIABLO/Smac is one of only a few specific proteins identified as substrates for the IMP complex in the mitochondrial intermembrane space.
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Affiliation(s)
- Lena Burri
- Russell Grimwade School of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
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