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Tian L, Li Y, Shi Y. Dark and Dronc activation in Drosophila melanogaster. Proc Natl Acad Sci U S A 2024; 121:e2312784121. [PMID: 38381783 PMCID: PMC10907274 DOI: 10.1073/pnas.2312784121] [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: 07/26/2023] [Accepted: 01/19/2024] [Indexed: 02/23/2024] Open
Abstract
The onset of apoptosis is characterized by a cascade of caspase activation, where initiator caspases are activated by a multimeric adaptor complex known as the apoptosome. In Drosophila melanogaster, the initiator caspase Dronc undergoes autocatalytic activation in the presence of the Dark apoptosome. Despite rigorous investigations, the activation mechanism for Dronc remains elusive. Here, we report the cryo-EM structures of an auto-inhibited Dark monomer and a single-layered, multimeric Dark/Dronc complex. Our biochemical analysis suggests that the auto-inhibited Dark oligomerizes upon binding to Dronc, which is sufficient for the activation of both Dark and Dronc. In contrast, the previously observed double-ring Dark apoptosome may represent a non-functional or "off-pathway" conformation. These findings expand our understanding on the molecular mechanism of apoptosis in Drosophila.
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Affiliation(s)
- Lu Tian
- Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
| | - Yini Li
- Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
| | - Yigong Shi
- Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
- Westlake Laboratory of Life Sciences and Biomedicine, Westlake Institute for Advanced Study, Hangzhou310024, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou310024, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou310024, China
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2
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Long S, Cao W, Qiu Y, Deng R, Liu J, Zhang L, Dong R, Liu F, Li S, Zhao H, Li N, Li K. The appearance of cytoplasmic cytochrome C precedes apoptosis during Drosophila salivary gland degradation. INSECT SCIENCE 2024; 31:157-172. [PMID: 37370257 DOI: 10.1111/1744-7917.13240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 05/16/2023] [Accepted: 05/22/2023] [Indexed: 06/29/2023]
Abstract
Apoptosis is an important process for organism development that functions to eliminate cell damage, maintain homeostasis, and remove obsolete tissues during morphogenesis. In mammals, apoptosis is accompanied by the release of cytochrome C (Cyt-c) from mitochondria to the cytoplasm. However, whether this process is conserved in the fruit fly, Drosophila melanogaster, remains controversial. In this study, we discovered that during the degradation of Drosophila salivary gland, the transcription of mitochondria apoptosis factors (MAPFs), Cyt-c, and death-associated APAF1-related killer (Dark) encoding genes are all upregulated antecedent to initiator and effector caspases encoding genes. The proteins Cyt-c and the active caspase 3 appear gradually in the cytoplasm during salivary gland degradation. Meanwhile, the Cyt-c protein colocates with mito-GFP, the marker indicating cytoplasmic mitochondria, and the change in mitochondrial membrane potential coincides with the appearance of Cyt-c in the cytoplasm. Moreover, impeding or promoting 20E-induced transcription factor E93 suppresses or enhances the staining of Cyt-c and the active caspase 3 in the cytoplasm of salivary gland, and accordingly decreases or increases the mitochondrial membrane potential, respectively. Our research provides evidence that cytoplasmic Cyt-c appears before apoptosis during Drosophila salivary gland degradation, shedding light on partial conserved mechanism in apoptosis between insects and mammals.
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Affiliation(s)
- Shihui Long
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Wenxin Cao
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Yongyu Qiu
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Ruohan Deng
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Jiali Liu
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Lidan Zhang
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Renke Dong
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Fengxin Liu
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Sheng Li
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
- Guangmeiyuan R&D Center, Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, South China Normal University, Meizhou, Guangdong Province, China
| | - Haigang Zhao
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
- ChemPartner PharmaTech Co., Ltd, Jiangmen, Guangdong Province, China
| | - Na Li
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
- Guangmeiyuan R&D Center, Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, South China Normal University, Meizhou, Guangdong Province, China
| | - Kang Li
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
- Guangmeiyuan R&D Center, Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, South China Normal University, Meizhou, Guangdong Province, China
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3
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Heron R, Amato C, Wood W, Davidson AJ. Understanding the diversity and dynamics of in vivo efferocytosis: Insights from the fly embryo. Immunol Rev 2023; 319:27-44. [PMID: 37589239 PMCID: PMC10952863 DOI: 10.1111/imr.13266] [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: 04/03/2023] [Accepted: 07/18/2023] [Indexed: 08/18/2023]
Abstract
The clearance of dead and dying cells, termed efferocytosis, is a rapid and efficient process and one that is critical for organismal health. The extraordinary speed and efficiency with which dead cells are detected and engulfed by immune cells within tissues presents a challenge to researchers who wish to unravel this fascinating process, since these fleeting moments of uptake are almost impossible to catch in vivo. In recent years, the fruit fly (Drosophila melanogaster) embryo has emerged as a powerful model to circumvent this problem. With its abundance of dying cells, specialist phagocytes and relative ease of live imaging, the humble fly embryo provides a unique opportunity to catch and study the moment of cell engulfment in real-time within a living animal. In this review, we explore the recent advances that have come from studies in the fly, and how live imaging and genetics have revealed a previously unappreciated level of diversity in the efferocytic program. A variety of efferocytic strategies across the phagocytic cell population ensure efficient and rapid clearance of corpses wherever death is encountered within the varied and complex setting of a multicellular living organism.
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Affiliation(s)
- Rosalind Heron
- Institute for Regeneration and RepairUniversity of EdinburghEdinburghUK
| | - Clelia Amato
- Institute for Regeneration and RepairUniversity of EdinburghEdinburghUK
| | - Will Wood
- Institute for Regeneration and RepairUniversity of EdinburghEdinburghUK
| | - Andrew J. Davidson
- Institute for Regeneration and RepairUniversity of EdinburghEdinburghUK
- School of Cancer SciencesWolfson Wohl Cancer Research Centre, University of GlasgowGlasgowUK
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4
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Joglekar I, Clark AC. Sequential Unfolding Mechanisms of Monomeric Caspases. Biochemistry 2023; 62:1878-1889. [PMID: 37337671 DOI: 10.1021/acs.biochem.3c00004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2023]
Abstract
Caspases are evolutionarily conserved cysteinyl proteases that are integral in cell development and apoptosis. All apoptotic caspases evolved from a common ancestor into two distinct subfamilies with either monomeric (initiators) or dimeric (effectors) oligomeric states. The regulation of apoptosis is influenced by the activation mechanism of the two subfamilies, but the evolution of the well-conserved caspase-hemoglobinase fold into the two subfamilies is not well understood. We examined the folding landscape of monomeric caspases from two coral species over a broad pH range of 3-10.5. On an evolutionary timescale, the two coral caspases diverged from each other approximately 300 million years ago, and they diverged from human caspases about 600 million years ago. Our results indicate that both proteins have overall high stability, ∼15 kcal mol-1, near the physiological pH range (pH 6-8) and unfold via two partially folded intermediates, I1 and I2*, that are in equilibrium with the native and the unfolded state. Like the dimeric caspases, the monomeric coral caspases undergo a pH-dependent conformational change resulting from the titration of an evolutionarily conserved site. Data from molecular dynamics simulations paired with limited proteolysis and MALDI-TOF mass spectrometry show that the small subunit of the monomeric caspases is unstable and unfolds prior to the large subunit. Overall, the data suggest that all caspases share a conserved folding landscape, that a conserved allosteric site can be fine-tuned for species-specific regulation, and that the subfamily of stable dimers may have evolved to stabilize the small subunit.
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Affiliation(s)
- Isha Joglekar
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76019, United States
| | - A Clay Clark
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76019, United States
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5
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Kaczmarek A, Wrońska AK, Boguś MI. The Changes in Mitochondrial Morphology and Physiology Accompanying Apoptosis in Galleria mellonella (Lepidoptera) Immunocompetent Cells during Conidiobolus coronatus (Entomophthorales) Infection. Int J Mol Sci 2023; 24:10169. [PMID: 37373316 DOI: 10.3390/ijms241210169] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/07/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
Mitochondria have been shown to play an important role in apoptosis using mammalian cell lines. However, their role in insects is not fully understood; thus, more indepth studies of insect cell apoptosis are necessary. The present study investigates mitochondrial involvement during Conidiobolus coronatus-induced apoptosis in Galleria mellonella hemocytes. Previous research has shown that fungal infection could induce apoptosis in insect hemocytes. Our findings indicate that mitochondria undergo several morphological and physiological changes during fungal infection, e.g., loss of mitochondrial membrane potential, megachannel formation, disturbances in intracellular respiration, increased nonrespiratory oxygen consumption in mitochondria, decreased ATP-coupled oxygen consumption and increased non-ATP-coupled oxygen consumption, decreased extracellular and intracellular oxygen consumption, and increased extracellular pH. Our findings confirm that G. mellonella immunocompetent cells demonstrate Ca2+ overload in mitochondria, translocation of cytochrome c-like protein from mitochondrial to cytosol fraction, and higher activation of caspase-9-like protein after C. coronatus infection. Most importantly, several of the changes observed in insect mitochondria are similar to those accompanying apoptosis in mammalian cells, suggesting that the process is evolutionarily conserved.
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Affiliation(s)
- Agata Kaczmarek
- Museum and Institute of Zoology, Polish Academy of Science, Wilcza 64, 00-679 Warsaw, Poland
- Witold Stefański Institute of Parasitology, Polish Academy of Sciences, Twarda 51/55, 00-875 Warsaw, Poland
| | - Anna Katarzyna Wrońska
- Museum and Institute of Zoology, Polish Academy of Science, Wilcza 64, 00-679 Warsaw, Poland
- Witold Stefański Institute of Parasitology, Polish Academy of Sciences, Twarda 51/55, 00-875 Warsaw, Poland
| | - Mieczysława Irena Boguś
- Museum and Institute of Zoology, Polish Academy of Science, Wilcza 64, 00-679 Warsaw, Poland
- Witold Stefański Institute of Parasitology, Polish Academy of Sciences, Twarda 51/55, 00-875 Warsaw, Poland
- Biomibo, 04-872 Warsaw, Poland
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6
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Frigo E, Tommasin L, Lippe G, Carraro M, Bernardi P. The Haves and Have-Nots: The Mitochondrial Permeability Transition Pore across Species. Cells 2023; 12:1409. [PMID: 37408243 PMCID: PMC10216546 DOI: 10.3390/cells12101409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/09/2023] [Accepted: 05/11/2023] [Indexed: 07/07/2023] Open
Abstract
The demonstration that F1FO (F)-ATP synthase and adenine nucleotide translocase (ANT) can form Ca2+-activated, high-conductance channels in the inner membrane of mitochondria from a variety of eukaryotes led to renewed interest in the permeability transition (PT), a permeability increase mediated by the PT pore (PTP). The PT is a Ca2+-dependent permeability increase in the inner mitochondrial membrane whose function and underlying molecular mechanisms have challenged scientists for the last 70 years. Although most of our knowledge about the PTP comes from studies in mammals, recent data obtained in other species highlighted substantial differences that could be perhaps attributed to specific features of F-ATP synthase and/or ANT. Strikingly, the anoxia and salt-tolerant brine shrimp Artemia franciscana does not undergo a PT in spite of its ability to take up and store Ca2+ in mitochondria, and the anoxia-resistant Drosophila melanogaster displays a low-conductance, selective Ca2+-induced Ca2+ release channel rather than a PTP. In mammals, the PT provides a mechanism for the release of cytochrome c and other proapoptotic proteins and mediates various forms of cell death. In this review, we cover the features of the PT (or lack thereof) in mammals, yeast, Drosophila melanogaster, Artemia franciscana and Caenorhabditis elegans, and we discuss the presence of the intrinsic pathway of apoptosis and of other forms of cell death. We hope that this exercise may help elucidate the function(s) of the PT and its possible role in evolution and inspire further tests to define its molecular nature.
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Affiliation(s)
- Elena Frigo
- Department of Biomedical Sciences and CNR Neuroscience Institute, University of Padova, Via Ugo Bassi 58/B, I-35131 Padova, Italy; (E.F.); (L.T.); (M.C.)
| | - Ludovica Tommasin
- Department of Biomedical Sciences and CNR Neuroscience Institute, University of Padova, Via Ugo Bassi 58/B, I-35131 Padova, Italy; (E.F.); (L.T.); (M.C.)
| | - Giovanna Lippe
- Department of Medicine, University of Udine, Piazzale Kolbe 4, I-33100 Udine, Italy;
| | - Michela Carraro
- Department of Biomedical Sciences and CNR Neuroscience Institute, University of Padova, Via Ugo Bassi 58/B, I-35131 Padova, Italy; (E.F.); (L.T.); (M.C.)
| | - Paolo Bernardi
- Department of Biomedical Sciences and CNR Neuroscience Institute, University of Padova, Via Ugo Bassi 58/B, I-35131 Padova, Italy; (E.F.); (L.T.); (M.C.)
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7
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Joglekar I, Clark AC. Sequential unfolding mechanisms of monomeric caspases. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.04.522771. [PMID: 36711547 PMCID: PMC9881926 DOI: 10.1101/2023.01.04.522771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Caspases are evolutionarily conserved cysteinyl proteases that are integral in cell development and apoptosis. All apoptotic caspases evolved from a common ancestor into two distinct subfamilies with either monomeric (initiators) or dimeric (effectors) oligomeric states. The regulation of apoptosis is influenced by the activation mechanism of the two subfamilies, but the evolution of the well-conserved caspase-hemoglobinase fold into the two subfamilies is not well understood. We examined the folding landscape of monomeric caspases from two coral species over a broad pH range of 3 to 10.5. On an evolutionary timescale, the two coral caspases diverged from each other approximately 300 million years ago, and they diverged from human caspases about 600 million years ago. Our results indicate that both proteins have overall high stability, ∼ 15 kcal mol -1 near the physiological pH range (pH 6 to pH 8), and unfold via two partially folded intermediates, I 1 and I 2 , that are in equilibrium with the native and the unfolded state. Like the dimeric caspases, the monomeric coral caspases undergo a pH-dependent conformational change resulting from the titration of an evolutionarily conserved site. Data from molecular dynamics simulations paired with limited proteolysis and MALDI-TOF mass spectrometry show that the small subunit of the monomeric caspases is unstable and unfolds prior to the large subunit. Overall, the data suggest that all caspases share a conserved folding landscape, that a conserved allosteric site can be fine-tuned for species-specific regulation, and that the subfamily of stable dimers may have evolved to stabilize the small subunit.
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Affiliation(s)
- Isha Joglekar
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - A. Clay Clark
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019,Corresponding author: A. Clay Clark,
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8
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Watase GJ, Nelson JO, Yamashita YM. Nonrandom sister chromatid segregation mediates rDNA copy number maintenance in Drosophila. SCIENCE ADVANCES 2022; 8:eabo4443. [PMID: 35895823 PMCID: PMC9328678 DOI: 10.1126/sciadv.abo4443] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 06/10/2022] [Indexed: 06/15/2023]
Abstract
Although considered to be exact copies of each other, sister chromatids can segregate nonrandomly in some cases. For example, sister chromatids of the X and Y chromosomes segregate nonrandomly during asymmetric division of male germline stem cells (GSCs) in Drosophila melanogaster. Here, we demonstrate that the ribosomal DNA (rDNA) loci, which are located on the X and Y chromosomes, and an rDNA binding protein Indra are required for nonrandom sister chromatid segregation (NRSS). We provide the evidence that NRSS, following unequal sister chromatid exchange, is a mechanism by which GSCs recover rDNA copy number, counteracting the spontaneous copy number loss that occurs during aging. Our study reveals an unexpected role for NRSS in maintaining germline immortality through maintenance of a vulnerable genomic element, rDNA.
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Affiliation(s)
- George J. Watase
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, 455 Main Street, Cambridge, MA 02142, USA
| | - Jonathan O. Nelson
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, 455 Main Street, Cambridge, MA 02142, USA
| | - Yukiko M. Yamashita
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, 455 Main Street, Cambridge, MA 02142, USA
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9
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The role of caspases as executioners of apoptosis. Biochem Soc Trans 2021; 50:33-45. [PMID: 34940803 DOI: 10.1042/bst20210751] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/29/2021] [Accepted: 12/06/2021] [Indexed: 12/13/2022]
Abstract
Caspases are a family of cysteine aspartyl proteases mostly involved in the execution of apoptotic cell death and in regulating inflammation. This article focuses primarily on the evolutionarily conserved function of caspases in apoptosis. We summarise which caspases are involved in apoptosis, how they are activated and regulated, and what substrates they target for cleavage to orchestrate programmed cell death by apoptosis.
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10
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Mitochondrion-Dependent Apoptosis Is Essential for Rickettsia parkeri Infection and Replication in Vector Cells. mSystems 2021; 6:6/2/e01209-20. [PMID: 33727398 PMCID: PMC8546998 DOI: 10.1128/msystems.01209-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Apoptosis is an innate immune response induced by infection in eukaryotes that contributes significantly to protection from pathogens. However, little is known about the role of apoptosis in the interactions of arthropod vectors with the rickettsiae that they transmit. Rickettsia spp. are vector-borne obligately intracellular bacteria and display different degrees of virulence in their eukaryotic hosts. In this study, we found that infection with Rickettsia parkeri (Rp) activated the apoptosis pathway in an Amblyomma americanum tick cell line (AAE2), as evidenced by the loss of phospholipid membrane asymmetry and DNA fragmentations. Additionally, infection with Rp also led to apoptosis activation in cell lines of different tick species. Interestingly, suppressing apoptosis decreased Rp infection and replication, while the activation of apoptosis increased Rp accumulation at the early stage of infection. Moreover, mitochondrion-dependent apoptosis was essential for Rp infection and replication in vector cells, and apoptosis induction required intracellular rickettsia replication. We further showed that Rp utilizes two different survival strategies to modulate apoptosis in the arthropod vectors and mammalian host cells. There was no direct correlation between apoptosis activation in vector cells and rickettsial pathogenicity. These novel findings indicate a possible mechanism whereby apoptosis facilitates infection and replication of a Rickettsia sp. in an arthropod vector. These results contribute to our understanding of how the vector's responses to pathogen infection affect pathogen replication and therefore transmission. IMPORTANCE Rickettsioses, infections caused by the genus Rickettsia, are among the oldest known infectious diseases. Ticks are essential arthropod vectors for rickettsiae, and knowledge about the interactions between ticks, their hosts, and pathogens is fundamental for identifying drivers of tick-borne rickettsioses. Despite the rapid development in apoptosis research with rickettsiae, little is known regarding the role of apoptosis in the interactions between Rickettsia spp., vertebrate hosts, and arthropod vectors. Here, we demonstrated that mitochondrion-dependent apoptosis is essential for rickettsial infection and replication in vector cells and that apoptosis induction requires intracellular rickettsial replication. However, rickettsial pathogenicity is not linked with apoptosis activation in tick cells. Our findings improve understanding of the apoptosis mechanism in arthropods exploited by rickettsiae and also the potential to discover specific targets for new vaccines and drugs to prevent or treat rickettsial infections.
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Shrestha S, Tung J, Grinshpon RD, Swartz P, Hamilton PT, Dimos B, Mydlarz L, Clark AC. Caspases from scleractinian coral show unique regulatory features. J Biol Chem 2020; 295:14578-14591. [PMID: 32788218 PMCID: PMC7586219 DOI: 10.1074/jbc.ra120.014345] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 08/04/2020] [Indexed: 12/11/2022] Open
Abstract
Coral reefs are experiencing precipitous declines around the globe with coral diseases and temperature-induced bleaching being primary drivers of these declines. Regulation of apoptotic cell death is an important component in the coral stress response. Although cnidaria are known to contain complex apoptotic signaling pathways, similar to those in vertebrates, the mechanisms leading to cell death are largely unexplored. We identified and characterized two caspases each from Orbicella faveolata, a disease-sensitive reef-building coral, and Porites astreoides, a disease-resistant reef-building coral. The caspases are predicted homologs of the human executioner caspases-3 and -7, but OfCasp3a (Orbicella faveolata caspase-3a) and PaCasp7a (Porites astreoides caspase-7a), which we show to be DXXDases, contain an N-terminal caspase activation/recruitment domain (CARD) similar to human initiator/inflammatory caspases. OfCasp3b (Orbicella faveolata caspase-3b) and PaCasp3 (Porites astreoides caspase-3), which we show to be VXXDases, have short pro-domains, like human executioner caspases. Our biochemical analyses suggest a mechanism in coral which differs from that of humans, where the CARD-containing DXXDase is activated on death platforms but the protease does not directly activate the VXXDase. The first X-ray crystal structure of a coral caspase, of PaCasp7a determined at 1.57 Å resolution, reveals a conserved fold and an N-terminal peptide bound near the active site that may serve as a regulatory exosite. The binding pocket has been observed in initiator caspases of other species. These results suggest mechanisms for the evolution of substrate selection while maintaining common activation mechanisms of CARD-mediated dimerization.
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Affiliation(s)
- Suman Shrestha
- Department of Biology, University of Texas at Arlington, Arlington, Texas, USA
| | - Jessica Tung
- Department of Biology, University of Texas at Arlington, Arlington, Texas, USA
| | - Robert D Grinshpon
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA
| | - Paul Swartz
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA
| | - Paul T Hamilton
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, USA
| | - Bradford Dimos
- Department of Biology, University of Texas at Arlington, Arlington, Texas, USA
| | - Laura Mydlarz
- Department of Biology, University of Texas at Arlington, Arlington, Texas, USA
| | - A Clay Clark
- Department of Biology, University of Texas at Arlington, Arlington, Texas, USA.
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12
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Wang XY, Wu KH, Pang HL, Xu PZ, Li MW, Zhang GZ. Study on the Role of Cytc in Response to BmNPV Infection in Silkworm, Bombyx mori (Lepidoptera). Int J Mol Sci 2019; 20:E4325. [PMID: 31487808 PMCID: PMC6770455 DOI: 10.3390/ijms20184325] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 08/29/2019] [Accepted: 09/02/2019] [Indexed: 01/02/2023] Open
Abstract
Bombyx mori nucleopolyhedrovirus (BmNPV) is one of the primary pathogens of the silkworm. Cytochrome c (cytc) showed a significant response to BmNPV infection in our previous transcriptome study. However, little is known about the role of Bombyx mori cytc (Bmcytc) in resistance to BmNPV infection. In this study, the expression levels analysis of Bmcytc showed stable expression levels in selected tissues of the resistant strain AN following BmNPV infection, while there was downregulation in the susceptible strain p50, except in the malpighian tubule. To further study the role of Bmcytc in viral infection, Bmcytc was knocked down with siRNA in vitro, resulting in significant downregulation of selected downstream genes of the mitochondrial pathway, including Bmapaf, Bmcaspase-Nc, and Bmcaspase-1; this was also confirmed by overexpression of Bmcytc using the pIZT/V5-His-mCherry insect vector, except Bmcaspase-1. Moreover, knockdown of Bmcytc significantly promoted the infection process of BmNPV in vitro, while the infection was inhibited by overexpression of Bmcytc at the early stage and subsequently increased rapidly. Based on these results, we concluded that Bmcytc plays a vital role in BmNPV infection by regulating the mitochondrial apoptosis pathway. Our work provides valuable data for the clarification of the mechanism of silkworm resistance to BmNPV infection.
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Affiliation(s)
- Xue-Yang Wang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China.
- The Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Science, Zhenjiang 212018, Jiangsu, China.
| | - Kang-Hui Wu
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China.
| | - Hui-Lin Pang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China.
| | - Ping-Zhen Xu
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China.
- The Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Science, Zhenjiang 212018, Jiangsu, China.
| | - Mu-Wang Li
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China.
- The Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Science, Zhenjiang 212018, Jiangsu, China.
| | - Guo-Zheng Zhang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China.
- The Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Science, Zhenjiang 212018, Jiangsu, China.
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13
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Dorstyn L, Akey CW, Kumar S. New insights into apoptosome structure and function. Cell Death Differ 2018; 25:1194-1208. [PMID: 29765111 DOI: 10.1038/s41418-017-0025-z] [Citation(s) in RCA: 132] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 10/23/2017] [Accepted: 10/25/2017] [Indexed: 02/08/2023] Open
Abstract
The apoptosome is a platform that activates apical procaspases in response to intrinsic cell death signals. Biochemical and structural studies in the past two decades have extended our understanding of apoptosome composition and structure, while illuminating the requirements for initiator procaspase activation. A number of studies have now provided high-resolution structures for apoptosomes from C. elegans (CED-4), D. melanogaster (Dark), and H. sapiens (Apaf-1), which define critical protein interfaces, including intra and interdomain interactions. This work also reveals interactions of apoptosomes with their respective initiator caspases, CED-3, Dronc and procaspase-9. Structures of the human apoptosome have defined the requirements for cytochrome c binding, which triggers the conversion of inactive Apaf-1 molecules to an extended, assembly competent state. While recent data have provided a detailed understanding of apoptosome formation and procaspase activation, they also highlight important evolutionary differences with functional implications for caspase activation. Comparison of the CARD/CARD disks and apoptosomes formed by CED-4, Dark and Apaf-1. Cartoons of the active states of the CARD-CARD disks, illustrating the two CED-4 CARD tetrameric ring layers (CED4a and CED4b; top row) and the binding of 8 Dronc CARDs and between 3-4 pc-9 CARDs, to the Dark and Apaf-1 CARD disk respectively (middle and lower rows). Ribbon diagrams of the active CED-4, Dark and Apaf-1 apoptosomes are shown (right column).
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Affiliation(s)
- Loretta Dorstyn
- Center for Cancer Biology, University of South Australia and SA Pathology, Frome Road, Adelaide, SA, 5001, Australia.
| | - Christopher W Akey
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA, 02118, USA
| | - Sharad Kumar
- Center for Cancer Biology, University of South Australia and SA Pathology, Frome Road, Adelaide, SA, 5001, Australia.
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14
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Starfish Apaf-1 activates effector caspase-3/9 upon apoptosis of aged eggs. Sci Rep 2018; 8:1611. [PMID: 29371610 PMCID: PMC5785508 DOI: 10.1038/s41598-018-19845-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 01/09/2018] [Indexed: 11/29/2022] Open
Abstract
Caspase-3-related DEVDase activity is initiated upon apoptosis in unfertilized starfish eggs. In this study, we cloned a starfish procaspase-3 corresponding to mammalian effector caspase containing a CARD that is similar to the amino terminal CARD of mammalian capsase-9, and we named it procaspase-3/9. Recombinant procaspase-3/9 expressed at 15 °C was cleaved to form active caspase-3/9 which has DEVDase activity. Microinjection of the active caspase-3/9 into starfish oocytes/eggs induced apoptosis. An antibody against the recombinant protein recognized endogenous procaspase-3/9 in starfish oocytes, which was cleaved upon apoptosis in aged unfertilized eggs. These results indicate that caspase-3/9 is an effector caspase in starfish. To verify the mechanism of caspase-3/9 activation, we cloned starfish Apaf-1 containing a CARD, a NOD, and 11 WD40 repeat regions, and we named it sfApaf-1. Recombinant sfApaf-1 CARD interacts with recombinant caspase-3/9 CARD and with endogenous procaspase-3/9 in cell-free preparations made from starfish oocytes, causing the formation of active caspase-3/9. When the cell-free preparation without mitochondria was incubated with inactive recombinant procaspase-3/9 expressed at 37 °C, DEVDase activity increased and apoptosome-like complexes were formed in the high molecular weight fractions containing both sfApaf-1 and cleaved caspase-3/9. These results suggest that sfApaf-1 activation is not dependent on cytochrome c.
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15
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Abstract
Apoptosis is a form of active cell death engaged by developmental cues as well as many different cellular stresses in which the dying cell essentially 'packages' itself for removal. The process of apoptotic cell death, as defined at the molecular level, is unique to the Metazoa (animals). Yet active cell death exists in non-animal organisms, and in some cases molecules involved in such death show some sequence similarities to those involved in apoptosis, leading to extensive speculation regarding the evolution of apoptosis. Here, we examine such speculation from the perspective of the functional properties of molecules of the mitochondrial apoptotic cell death pathway. We suggest scenarios for the evolution of one pathway of apoptosis, the mitochondrial pathway, and consider how they might be tested. We conclude with a 'Just So Story' of how the mitochondrial pathway of apoptosis might have evolved during eukaryotic evolution.
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Affiliation(s)
- Douglas R Green
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
| | - Patrick Fitzgerald
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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16
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Transcriptome analysis of Spodoptera frugiperda Sf9 cells reveals putative apoptosis-related genes and a preliminary apoptosis mechanism induced by azadirachtin. Sci Rep 2017; 7:13231. [PMID: 29038528 PMCID: PMC5643380 DOI: 10.1038/s41598-017-12713-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 09/18/2017] [Indexed: 12/20/2022] Open
Abstract
As an important botanical pesticide, azadirachtin demonstrates broad insecticidal activity against many agricultural pests. The results of a previous study indicated the toxicity and apoptosis induction of azadirachtin in Spodoptera frugiperda Sf9 cells. However, the lack of genomic data has hindered a deeper investigation of apoptosis in Sf9 cells at a molecular level. In the present study, the complete transcriptome data for Sf9 cell line was accomplished using Illumina sequencing technology, and 97 putative apoptosis-related genes were identified through BLAST and KEGG orthologue annotations. Fragments of potential candidate apoptosis-related genes were cloned, and the mRNA expression patterns of ten identified genes regulated by azadirachtin were examined using qRT-PCR. Furthermore, Western blot analysis showed that six putative apoptosis-related proteins were upregulated after being treated with azadirachtin while the protein Bcl-2 were downregulated. These data suggested that both intrinsic and extrinsic apoptotic signal pathways comprising the identified potential apoptosis-related genes were potentially active in S. frugiperda. In addition, the preliminary results revealed that caspase-dependent or caspase-independent apoptotic pathways could function in azadirachtin-induced apoptosis in Sf9 cells.
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17
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Li Y, Zhang L, Qu T, Tang X, Li L, Zhang G. Conservation and divergence of mitochondrial apoptosis pathway in the Pacific oyster, Crassostrea gigas. Cell Death Dis 2017; 8:e2915. [PMID: 28682310 PMCID: PMC5550854 DOI: 10.1038/cddis.2017.307] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 05/27/2017] [Accepted: 05/31/2017] [Indexed: 02/07/2023]
Abstract
Apoptosis is considered a crucial part of the host defense system in oysters according to previous reports; however, the exact process by which this occurs remains unclear. Besides, mitochondrial apoptosis is the primary method of apoptosis in vertebrate cells, but has been poorly studied in invertebrates and is quite controversial. In this study, we investigated the molecular mechanism of mitochondrial apoptosis in the Pacific oyster Crassostrea gigas. Notably, we show that most key elements involved in the vertebrate mitochondrial apoptosis pathway – including mitochondrial outer membrane permeabilization, cytochrome c release, and caspase activation – are also present in C. gigas. In contrast, the lack of Bcl-2 homology 3-only subfamily members and apoptotic protease activating factor-1 (APAF-1) protein revealed evolutionary diversity from other phyla. Our results support that mitochondrial apoptosis in animals predates the emergence of vertebrates, but suggest that an unexpectedly diverse mitochondrial apoptosis pathway may exist in invertebrates. In addition, our work provided new clues for an improved understanding of how bivalve acclimate themselves to an inconstant environment.
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Affiliation(s)
- Yingxiang Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,National &Local Joint Engineering Laboratory of Ecological Mariculture, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Linlin Zhang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,National &Local Joint Engineering Laboratory of Ecological Mariculture, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Tao Qu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,National &Local Joint Engineering Laboratory of Ecological Mariculture, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Xueying Tang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,National &Local Joint Engineering Laboratory of Ecological Mariculture, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Li Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,National &Local Joint Engineering Laboratory of Ecological Mariculture, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Guofan Zhang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,National &Local Joint Engineering Laboratory of Ecological Mariculture, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
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18
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Xie K, Tian L, Guo X, Li K, Li J, Deng X, Li Q, Xia Q, Zhong Y, Huang Z, Liu J, Li S, Yang W, Cao Y. BmATG5 and BmATG6 mediate apoptosis following autophagy induced by 20-hydroxyecdysone or starvation. Autophagy 2016; 12:381-96. [PMID: 26727186 DOI: 10.1080/15548627.2015.1134079] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Autophagy and apoptosis, which could be induced by common stimuli, play crucial roles in development and disease. The functional relationship between autophagy and apoptosis is complex, due to the dual effects of autophagy. In the Bombyx Bm-12 cells, 20-hydroxyecdysone (20E) treatment or starvation-induced cell death, with autophagy preceding apoptosis. In response to 20E or starvation, BmATG8 was rapidly cleaved and conjugated with PE to form BmATG8-PE; subsequently, BmATG5 and BmATG6 were cleaved into BmATG5-tN and BmATG6-C, respectively. Reduction of expression of BmAtg5 or BmAtg6 by RNAi decreased the proportion of cells undergoing both autophagy and apoptosis after 20E treatment or starvation. Overexpression of BmAtg5 or BmAtg6 induced autophagy but not apoptosis in the absence of the stimuli, but promoted both autophagy and apoptosis induced by 20E or starvation. Notably, overexpression of cleavage site-deleted BmAtg5 or BmAtg6 increased autophagy but not apoptosis induced by 20E or starvation, whereas overexpression of BmAtg5-tN and BmAtg6-C was able to directly trigger apoptosis or promote the induced apoptosis. In conclusion, being cleaved into BmATG5-tN and BmATG6-C, BmATG5 and BmATG6 mediate apoptosis following autophagy induced by 20E or starvation in Bombyx Bm-12 cells, reflecting that autophagy precedes apoptosis in the midgut during Bombyx metamorphosis.
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Affiliation(s)
- Kun Xie
- a Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding/Guangdong Provincial Sericulture and Mulberry Engineering Research Center, College of Animal Science, South China Agricultural University , Guangzhou , China.,b Key Laboratory of Crops with High Quality and Efficient Cultivation and Security Control, Yunnan Higher Education Institutions, College of Life Science and Technology, HongHe University , Mengzi , Yunnan , China
| | - Ling Tian
- a Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding/Guangdong Provincial Sericulture and Mulberry Engineering Research Center, College of Animal Science, South China Agricultural University , Guangzhou , China.,c Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai , China
| | - Xinyu Guo
- a Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding/Guangdong Provincial Sericulture and Mulberry Engineering Research Center, College of Animal Science, South China Agricultural University , Guangzhou , China
| | - Kang Li
- a Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding/Guangdong Provincial Sericulture and Mulberry Engineering Research Center, College of Animal Science, South China Agricultural University , Guangzhou , China.,c Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai , China
| | - Jianping Li
- a Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding/Guangdong Provincial Sericulture and Mulberry Engineering Research Center, College of Animal Science, South China Agricultural University , Guangzhou , China
| | - Xiaojuan Deng
- a Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding/Guangdong Provincial Sericulture and Mulberry Engineering Research Center, College of Animal Science, South China Agricultural University , Guangzhou , China
| | - Qingrong Li
- d The Sericultural and Agri-Food Research Institute of the Guangdong Academy of Agricultural Sciences , Guangzhou , China
| | - Qingyou Xia
- e State Key Laboratory of Silkworm Genome Biology, Southwest University , Chongqing , China
| | - Yangjin Zhong
- a Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding/Guangdong Provincial Sericulture and Mulberry Engineering Research Center, College of Animal Science, South China Agricultural University , Guangzhou , China
| | - Zhijun Huang
- a Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding/Guangdong Provincial Sericulture and Mulberry Engineering Research Center, College of Animal Science, South China Agricultural University , Guangzhou , China
| | - Jiping Liu
- a Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding/Guangdong Provincial Sericulture and Mulberry Engineering Research Center, College of Animal Science, South China Agricultural University , Guangzhou , China
| | - Sheng Li
- c Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai , China
| | - Wanying Yang
- a Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding/Guangdong Provincial Sericulture and Mulberry Engineering Research Center, College of Animal Science, South China Agricultural University , Guangzhou , China
| | - Yang Cao
- a Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding/Guangdong Provincial Sericulture and Mulberry Engineering Research Center, College of Animal Science, South China Agricultural University , Guangzhou , China
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19
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Cheng TC, Akey IV, Yuan S, Yu Z, Ludtke SJ, Akey CW. A Near-Atomic Structure of the Dark Apoptosome Provides Insight into Assembly and Activation. Structure 2016; 25:40-52. [PMID: 27916517 DOI: 10.1016/j.str.2016.11.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 09/11/2016] [Accepted: 10/27/2016] [Indexed: 11/19/2022]
Abstract
In Drosophila, the Apaf-1-related killer (Dark) forms an apoptosome that activates procaspases. To investigate function, we have determined a near-atomic structure of Dark double rings using cryo-electron microscopy. We then built a nearly complete model of the apoptosome that includes 7- and 8-blade β-propellers. We find that the preference for dATP during Dark assembly may be governed by Ser325, which is in close proximity to the 2' carbon of the deoxyribose ring. Interestingly, β-propellers in V-shaped domains of the Dark apoptosome are more widely separated, relative to these features in the Apaf-1 apoptosome. This wider spacing may be responsible for the lack of cytochrome c binding to β-propellers in the Dark apoptosome. Our structure also highlights the roles of two loss-of-function mutations that may block Dark assembly. Finally, the improved model provides a framework to understand apical procaspase activation in the intrinsic cell death pathway.
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Affiliation(s)
- Tat Cheung Cheng
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA
| | - Ildikó V Akey
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA
| | - Shujun Yuan
- Department of Biologics Research - Protein Sciences, U.S. Innovation Center, Bayer Healthcare, 455 Mission Bay Boulevard South, San Francisco, CA 94158, USA
| | - Zhiheng Yu
- Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Steven J Ludtke
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA
| | - Christopher W Akey
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA.
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20
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Chen RT, Jiao P, Lu Y, Xin HH, Zhang DP, Wang MX, Liang S, Miao YG. BMDREDD REGULATES THE APOPTOSIS COORDINATING WITH BMDAXX, BMCIDE-B, BMFADD, AND BMCREB IN BMN CELLS. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2016; 93:160-173. [PMID: 27558456 DOI: 10.1002/arch.21349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The apoptosis mechanisms in mammals were investigated relatively clearly. However, little is known about how apoptosis is achieved at a molecular level in silkworm cells. We cloned a caspase homologous gene named BmDredd (where Bm is Bombyx mori and Dredd is death-related ced-3/Nedd2-like caspase) in BmN cells from the ovary of Bm and analyzed its biological information. We constructed the N-terminal, C-terminal, and overexpression vector of BmDredd, respectively. Our results showed that the transcriptional expression level of BmDredd was increased in the apoptotic BmN cells. Furthermore, overexpression of BmDredd increased the caspase-3/7 activity. Simultaneously, RNAi of BmDredd could save BmN cells from apoptosis. The immunofluorescence study showed that BmDredd located at the cytoplasm in normal cell otherwise is found at the nucleus when cells undergo apoptosis. Moreover, we quantified the transcriptional expressions of apoptosis-related genes including BmDredd, BmDaxx (where Daxx is death-domain associated protein), BmCide-b (where Cide-b is cell death inducing DFF45-like effector), BmFadd (Fadd is fas-associated via death domain), and BmCreb (where Creb is cAMP-response element binding protein) in BmN cells with dsRNA interferences to detect the molecular mechanism of apoptosis. In conclusion, BmDredd may function for promoting apoptosis and there are various regulatory interactions among these apoptosis-related genes.
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Affiliation(s)
- Rui-Ting Chen
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, P. R. China
| | - Peng Jiao
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, P. R. China
| | - Yan Lu
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, P. R. China
| | - Hu-Hu Xin
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, P. R. China
| | - Deng-Pan Zhang
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, P. R. China
| | - Mei-Xian Wang
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, P. R. China
| | - Shuang Liang
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, P. R. China
| | - Yun-Gen Miao
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, P. R. China.
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21
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Clavier A, Rincheval-Arnold A, Mignotte B, Guénal I. [The comeback of mitochondria in Drosophila apoptosis]. Med Sci (Paris) 2016; 32:478-84. [PMID: 27225920 DOI: 10.1051/medsci/20163205014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The role of the mitochondrion in mammalian cell apoptosis has been established since the mid-1990s. However, the importance of this organelle in non-mammalian apoptosis has long been regarded as minor, notably because of the absence of a crucial role for cytochrome c in caspase activation. Recent results indicate that the control of caspase activation and apoptosis in Drosophila cell death occurs at the mitochondrial level. Numerous proteins that appear key for Drosophila apoptosis regulation constitutively or transiently bind to mitochondria. They participate in the cell death process at different levels such as degradation of an IAP caspase inhibitor, production of mitochondrial reactive oxygen species or stimulation of the mitochondrial fission machinery. The aim of this review is to take stock of these events that might have their counterpart in humans.
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Affiliation(s)
- Amandine Clavier
- Laboratoire de génétique et biologie cellulaire, université de Versailles Saint-Quentin-en-Yvelines, université Paris-Saclay, 2, avenue de la Source de la Bièvre, 78180 Montigny-le-Bretonneux, France - Laboratoire de génétique moléculaire et physiologique, École pratique des hautes études, PSL research university, 78180 Montigny-le-Bretonneux, France
| | - Aurore Rincheval-Arnold
- Laboratoire de génétique et biologie cellulaire, université de Versailles Saint-Quentin-en-Yvelines, université Paris-Saclay, 2, avenue de la Source de la Bièvre, 78180 Montigny-le-Bretonneux, France
| | - Bernard Mignotte
- Laboratoire de génétique et biologie cellulaire, université de Versailles Saint-Quentin-en-Yvelines, université Paris-Saclay, 2, avenue de la Source de la Bièvre, 78180 Montigny-le-Bretonneux, France - Laboratoire de génétique moléculaire et physiologique, École pratique des hautes études, PSL research university, 78180 Montigny-le-Bretonneux, France
| | - Isabelle Guénal
- Laboratoire de génétique et biologie cellulaire, université de Versailles Saint-Quentin-en-Yvelines, université Paris-Saclay, 2, avenue de la Source de la Bièvre, 78180 Montigny-le-Bretonneux, France
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22
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Mitochondrial calcium uniporter regulator 1 (MCUR1) regulates the calcium threshold for the mitochondrial permeability transition. Proc Natl Acad Sci U S A 2016; 113:E1872-80. [PMID: 26976564 DOI: 10.1073/pnas.1602264113] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
During the mitochondrial permeability transition, a large channel in the inner mitochondrial membrane opens, leading to the loss of multiple mitochondrial solutes and cell death. Key triggers include excessive reactive oxygen species and mitochondrial calcium overload, factors implicated in neuronal and cardiac pathophysiology. Examining the differential behavior of mitochondrial Ca(2+) overload in Drosophila versus human cells allowed us to identify a gene, MCUR1, which, when expressed in Drosophila cells, conferred permeability transition sensitive to electrophoretic Ca(2+) uptake. Conversely, inhibiting MCUR1 in mammalian cells increased the Ca(2+) threshold for inducing permeability transition. The effect was specific to the permeability transition induced by Ca(2+), and such resistance to overload translated into improved cell survival. Thus, MCUR1 expression regulates the Ca(2+) threshold required for permeability transition.
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23
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Hwangbo DS, Biteau B, Rath S, Kim J, Jasper H. Control of apoptosis by Drosophila DCAF12. Dev Biol 2016; 413:50-9. [PMID: 26972874 DOI: 10.1016/j.ydbio.2016.03.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 01/08/2016] [Accepted: 03/05/2016] [Indexed: 11/30/2022]
Abstract
Regulated Apoptosis (Programmed Cell Death, PCD) maintains tissue homeostasis in adults, and ensures proper growth and morphogenesis of tissues during development of metazoans. Accordingly, defects in cellular processes triggering or executing apoptotic programs have been implicated in a variety of degenerative and neoplastic diseases. Here, we report the identification of DCAF12, an evolutionary conserved member of the WD40-motif repeat family of proteins, as a new regulator of apoptosis in Drosophila. We find that DCAF12 is required for Diap1 cleavage in response to pro-apoptotic signals, and is thus necessary and sufficient for RHG (Reaper, Hid, and Grim)-mediated apoptosis. Loss of DCAF12 perturbs the elimination of supernumerary or proliferation-impaired cells during development, and enhances tumor growth induced by loss of neoplastic tumor suppressors, highlighting the wide requirement for DCAF12 in PCD.
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Affiliation(s)
- Dae-Sung Hwangbo
- Department of Biology, University of Rochester, River Campus Box 270211, Rochester, NY 14627, USA; Department of Biomedical Genetics, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Benoit Biteau
- Department of Biomedical Genetics, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Sneha Rath
- Department of Biology, University of Rochester, River Campus Box 270211, Rochester, NY 14627, USA
| | - Jihyun Kim
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945-1400, USA
| | - Heinrich Jasper
- Department of Biology, University of Rochester, River Campus Box 270211, Rochester, NY 14627, USA; Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945-1400, USA.
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24
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Zhang Y, Liu S, Yang X, Yang M, Xu W, Li Y, Tao L. Staurosporine shows insecticidal activity against Mythimna separata Walker (Lepidoptera: Noctuidae) potentially via induction of apoptosis. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2016; 128:37-44. [PMID: 26969438 DOI: 10.1016/j.pestbp.2015.10.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 09/20/2015] [Accepted: 10/07/2015] [Indexed: 06/05/2023]
Abstract
Staurosporine (STS), a wide-spectrum kinase inhibitor, is widely used in studies of apoptosis in mammalian cells. However, its physiological and mechanistic effects have never been clearly defined in insect cells, and other applications of STS have rarely been reported. The present study reveals the insecticidal activity of STS on larvae of Mythimna separata Walker, and the apoptotic mechanism induced by STS on lepidopteran Sf9 cell lines. We demonstrate that the viability of Sf9 cells is inhibited by STS in a time- and concentration-dependent manner. Intracellular biochemical assays show that STS-induced apoptosis of Sf9 cells coincides with a decrease in the mitochondrial membrane potential, the release of cytochrome c into the cytosol, a significant increase of the Bax/Bcl-2 ratio, and a marked activation of caspase-9 and caspase-3. These results indicate that a mitochondrial-dependent intrinsic pathway contributes to STS induced caspase-3 activation and apoptosis in Sf9 cells which is homologous to the mechanisms in mammalian cells. This study contributes to our understanding of the mechanism of insect cell apoptosis and suggests a possible new application of STS as a potential insecticide against Lepidopteran insect pests in agriculture.
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Affiliation(s)
- Yang Zhang
- Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Songlin Liu
- Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Xing Yang
- Shanghai Pesticide Research Institute, Shanghai 200032, China
| | - Mingjun Yang
- Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Wenping Xu
- Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Yaxiao Li
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Liming Tao
- Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China.
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25
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Clavier A, Rincheval-Arnold A, Colin J, Mignotte B, Guénal I. Apoptosis in Drosophila: which role for mitochondria? Apoptosis 2015; 21:239-51. [DOI: 10.1007/s10495-015-1209-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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26
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Bernardi P, Rasola A, Forte M, Lippe G. The Mitochondrial Permeability Transition Pore: Channel Formation by F-ATP Synthase, Integration in Signal Transduction, and Role in Pathophysiology. Physiol Rev 2015; 95:1111-55. [PMID: 26269524 DOI: 10.1152/physrev.00001.2015] [Citation(s) in RCA: 420] [Impact Index Per Article: 46.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The mitochondrial permeability transition (PT) is a permeability increase of the inner mitochondrial membrane mediated by a channel, the permeability transition pore (PTP). After a brief historical introduction, we cover the key regulatory features of the PTP and provide a critical assessment of putative protein components that have been tested by genetic analysis. The discovery that under conditions of oxidative stress the F-ATP synthases of mammals, yeast, and Drosophila can be turned into Ca(2+)-dependent channels, whose electrophysiological properties match those of the corresponding PTPs, opens new perspectives to the field. We discuss structural and functional features of F-ATP synthases that may provide clues to its transition from an energy-conserving into an energy-dissipating device as well as recent advances on signal transduction to the PTP and on its role in cellular pathophysiology.
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Affiliation(s)
- Paolo Bernardi
- Department of Biomedical Sciences and Consiglio Nazionale delle Ricerche Neuroscience Institute, University of Padova, Padova, Italy; Vollum Institute, Oregon Health and Sciences University, Portland, Oregon; and Department of Food Science, University of Udine, Udine, Italy
| | - Andrea Rasola
- Department of Biomedical Sciences and Consiglio Nazionale delle Ricerche Neuroscience Institute, University of Padova, Padova, Italy; Vollum Institute, Oregon Health and Sciences University, Portland, Oregon; and Department of Food Science, University of Udine, Udine, Italy
| | - Michael Forte
- Department of Biomedical Sciences and Consiglio Nazionale delle Ricerche Neuroscience Institute, University of Padova, Padova, Italy; Vollum Institute, Oregon Health and Sciences University, Portland, Oregon; and Department of Food Science, University of Udine, Udine, Italy
| | - Giovanna Lippe
- Department of Biomedical Sciences and Consiglio Nazionale delle Ricerche Neuroscience Institute, University of Padova, Padova, Italy; Vollum Institute, Oregon Health and Sciences University, Portland, Oregon; and Department of Food Science, University of Udine, Udine, Italy
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27
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Clavier A, Ruby V, Rincheval-Arnold A, Mignotte B, Guénal I. The Drosophila retinoblastoma protein, Rbf1, induces a Debcl- and Drp1-dependent mitochondrial apoptosis. J Cell Sci 2015. [PMID: 26208635 DOI: 10.1242/jcs.169896] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
In accordance with its tumor suppressor role, the retinoblastoma protein pRb can ensure pro-apoptotic functions. Rbf1, the Drosophila homolog of Rb, also displays a pro-apoptotic activity in proliferative cells. We have previously shown that the Rbf1 pro-apoptotic activity depends on its ability to decrease the level of anti-apoptotic proteins such as the Bcl-2 family protein Buffy. Buffy often acts in an opposite manner to Debcl, the other Drosophila Bcl-2-family protein. Both proteins can localize at the mitochondrion, but the way they control apoptosis still remains unclear. Here, we demonstrate that Debcl and the pro-fission gene Drp1 are necessary downstream of Buffy to trigger a mitochondrial fragmentation during Rbf1-induced apoptosis. Interestingly, Rbf1-induced apoptosis leads to a Debcl- and Drp1-dependent reactive oxygen species production, which in turn activates the Jun Kinase pathway to trigger cell death. Moreover, we show that Debcl and Drp1 can interact and that Buffy inhibits this interaction. Notably, Debcl modulates Drp1 mitochondrial localization during apoptosis. These results provide a mechanism by which Drosophila Bcl-2 family proteins can control apoptosis, and shed light on a link between Rbf1 and mitochondrial dynamics in vivo.
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Affiliation(s)
- Amandine Clavier
- Université de Versailles Saint-Quentin-en-Yvelines, Laboratoire de Génétique et Biologie Cellulaire, EA4589, 2 avenue de la Source de la Bièvre, Montigny-le-Bretonneux 78180, France Ecole Pratique des Hautes Etudes, Laboratoire de Génétique et Biologie Cellulaire, 2 avenue de la Source de la Bièvre, Montigny-le-Bretonneux 78180, France
| | - Vincent Ruby
- Université de Versailles Saint-Quentin-en-Yvelines, Laboratoire de Génétique et Biologie Cellulaire, EA4589, 2 avenue de la Source de la Bièvre, Montigny-le-Bretonneux 78180, France
| | - Aurore Rincheval-Arnold
- Université de Versailles Saint-Quentin-en-Yvelines, Laboratoire de Génétique et Biologie Cellulaire, EA4589, 2 avenue de la Source de la Bièvre, Montigny-le-Bretonneux 78180, France
| | - Bernard Mignotte
- Université de Versailles Saint-Quentin-en-Yvelines, Laboratoire de Génétique et Biologie Cellulaire, EA4589, 2 avenue de la Source de la Bièvre, Montigny-le-Bretonneux 78180, France Ecole Pratique des Hautes Etudes, Laboratoire de Génétique et Biologie Cellulaire, 2 avenue de la Source de la Bièvre, Montigny-le-Bretonneux 78180, France
| | - Isabelle Guénal
- Université de Versailles Saint-Quentin-en-Yvelines, Laboratoire de Génétique et Biologie Cellulaire, EA4589, 2 avenue de la Source de la Bièvre, Montigny-le-Bretonneux 78180, France
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28
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Abstract
The apoptotic machinery is highly conserved throughout evolution, and central to the regulation of apoptosis is the caspase family of cysteine proteases. Insights into the regulation and function of apoptosis in mammals have come from studies using model organisms. Drosophila provides an exceptional model system for identifying the function of conserved mechanisms regulating apoptosis, especially during development. The characteristic patterns of apoptosis during Drosophila development have been well described, as has the apoptotic response following DNA damage. The focus of this discussion is to introduce methodologies for monitoring apoptosis during Drosophila development and also in Drosophila cell lines.
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Affiliation(s)
- Donna Denton
- Centre for Cancer Biology, University of South Australia, Adelaide, South Australia 5001, Australia
| | - Sharad Kumar
- Centre for Cancer Biology, University of South Australia, Adelaide, South Australia 5001, Australia
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29
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Accorsi A, Zibaee A, Malagoli D. The multifaceted activity of insect caspases. JOURNAL OF INSECT PHYSIOLOGY 2015; 76:17-23. [PMID: 25783954 DOI: 10.1016/j.jinsphys.2015.03.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 02/09/2015] [Accepted: 03/09/2015] [Indexed: 06/04/2023]
Abstract
Caspases are frequently considered synonymous with apoptotic cell death. Increasing evidence demonstrates that these proteases may exert their activities in non-apoptotic functions. The non-apoptotic roles of caspases may include developmentally regulated autophagy during insect metamorphosis, as well as neuroblast self-renewal and the immune response. Here, we summarize the established knowledge and the recent advances in the multiple roles of insect caspases to highlight their relevance for physiological processes and survival.
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Affiliation(s)
- A Accorsi
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - A Zibaee
- Department of Plant Protection, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran
| | - D Malagoli
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy.
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30
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von Stockum S, Giorgio V, Trevisan E, Lippe G, Glick GD, Forte MA, Da-Rè C, Checchetto V, Mazzotta G, Costa R, Szabò I, Bernardi P. F-ATPase of Drosophila melanogaster forms 53-picosiemen (53-pS) channels responsible for mitochondrial Ca2+-induced Ca2+ release. J Biol Chem 2014; 290:4537-4544. [PMID: 25550160 DOI: 10.1074/jbc.c114.629766] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mitochondria of Drosophila melanogaster undergo Ca(2+)-induced Ca(2+) release through a putative channel (mCrC) that has several regulatory features of the permeability transition pore (PTP). The PTP is an inner membrane channel that forms from F-ATPase, possessing a conductance of 500 picosiemens (pS) in mammals and of 300 pS in yeast. In contrast to the PTP, the mCrC of Drosophila is not permeable to sucrose and appears to be selective for Ca(2+) and H(+). We show (i) that like the PTP, the mCrC is affected by the sense of rotation of F-ATPase, by Bz-423, and by Mg(2+)/ADP; (ii) that expression of human cyclophilin D in mitochondria of Drosophila S2R(+) cells sensitizes the mCrC to Ca(2+) but does not increase its apparent size; and (iii) that purified dimers of D. melanogaster F-ATPase reconstituted into lipid bilayers form 53-pS channels activated by Ca(2+) and thiol oxidants and inhibited by Mg(2+)/γ-imino ATP. These findings indicate that the mCrC is the PTP of D. melanogaster and that the signature conductance of F-ATPase channels depends on unique structural features that may underscore specific roles in different species.
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Affiliation(s)
| | | | | | - Giovanna Lippe
- the Department of Food Science, University of Udine, I-33100 Udine, Italy
| | - Gary D Glick
- the Department of Chemistry, Graduate Program in Immunology, University of Michigan, Ann Arbor, Michigan 48109, and
| | - Michael A Forte
- the Vollum Institute, Oregon Health and Sciences University, Portland, Oregon 97239
| | - Caterina Da-Rè
- Biology, University of Padova and Consiglio Nazionale delle Ricerche Neuroscience Institute, I-35131 Padova, Italy
| | - Vanessa Checchetto
- Biology, University of Padova and Consiglio Nazionale delle Ricerche Neuroscience Institute, I-35131 Padova, Italy
| | - Gabriella Mazzotta
- Biology, University of Padova and Consiglio Nazionale delle Ricerche Neuroscience Institute, I-35131 Padova, Italy
| | - Rodolfo Costa
- Biology, University of Padova and Consiglio Nazionale delle Ricerche Neuroscience Institute, I-35131 Padova, Italy
| | - Ildikò Szabò
- Biology, University of Padova and Consiglio Nazionale delle Ricerche Neuroscience Institute, I-35131 Padova, Italy
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31
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Denton D, Aung-Htut MT, Lorensuhewa N, Nicolson S, Zhu W, Mills K, Cakouros D, Bergmann A, Kumar S. UTX coordinates steroid hormone-mediated autophagy and cell death. Nat Commun 2014; 4:2916. [PMID: 24336022 DOI: 10.1038/ncomms3916] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 11/12/2013] [Indexed: 02/07/2023] Open
Abstract
Correct spatial and temporal induction of numerous cell type-specific genes during development requires regulated removal of the repressive histone H3 lysine 27 trimethylation (H3K27me3) modification. Here we show that the H3K27me3 demethylase dUTX is required for hormone-mediated transcriptional regulation of apoptosis and autophagy genes during ecdysone-regulated programmed cell death of Drosophila salivary glands. We demonstrate that dUTX binds to the nuclear hormone receptor complex Ecdysone Receptor/Ultraspiracle, and is recruited to the promoters of key apoptosis and autophagy genes. Salivary gland cell death is delayed in dUTX mutants, with reduced caspase activity and autophagy that coincides with decreased apoptosis and autophagy gene transcripts. We further show that salivary gland degradation requires dUTX catalytic activity. Our findings provide evidence for an unanticipated role for UTX demethylase activity in regulating hormone-dependent cell death and demonstrate how a single transcriptional regulator can modulate a specific complex functional outcome during animal development.
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Affiliation(s)
- Donna Denton
- 1] Centre for Cancer Biology, SA Pathology, Frome Road, Adelaide, South Australia 5000, Australia [2] Division of Health Sciences, University of South Australia, Adelaide, South Australia 5001, Australia
| | - May T Aung-Htut
- Centre for Cancer Biology, SA Pathology, Frome Road, Adelaide, South Australia 5000, Australia
| | - Nirmal Lorensuhewa
- Centre for Cancer Biology, SA Pathology, Frome Road, Adelaide, South Australia 5000, Australia
| | - Shannon Nicolson
- Centre for Cancer Biology, SA Pathology, Frome Road, Adelaide, South Australia 5000, Australia
| | - Wenying Zhu
- Centre for Cancer Biology, SA Pathology, Frome Road, Adelaide, South Australia 5000, Australia
| | - Kathryn Mills
- Centre for Cancer Biology, SA Pathology, Frome Road, Adelaide, South Australia 5000, Australia
| | - Dimitrios Cakouros
- Centre for Cancer Biology, SA Pathology, Frome Road, Adelaide, South Australia 5000, Australia
| | - Andreas Bergmann
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Sharad Kumar
- 1] Centre for Cancer Biology, SA Pathology, Frome Road, Adelaide, South Australia 5000, Australia [2] Division of Health Sciences, University of South Australia, Adelaide, South Australia 5001, Australia [3] Department of Medicine, The University of Adelaide, Adelaide, South Australia 5005, Australia
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32
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Chan EYL, McQuibban GA. The mitochondrial rhomboid protease: its rise from obscurity to the pinnacle of disease-relevant genes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2916-25. [PMID: 24099009 DOI: 10.1016/j.bbamem.2013.05.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 05/08/2013] [Accepted: 05/10/2013] [Indexed: 12/15/2022]
Abstract
The Rhomboid proteases belong to a highly conserved family of proteins that are present in all branches of life. In Drosophila, the secretory pathway-localized rhomboid proteases are crucial for epidermal growth factor (EGF) signaling. The identification of a mitochondrial-localized rhomboid protease shed light on other functions of rhomboid proteases including the maintenance of mitochondrial morphology and the regulation of apoptosis. More recent work has revealed other functions of the mitochondrial rhomboid protease in mitochondrial and cellular biology, failure of which have been implicated in human diseases. In this review, we will summarize the current knowledge and disease relevance of the mitochondrial-localized rhomboid protease. This article is part of a Special Issue entitled: Intramembrane Proteases.
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Affiliation(s)
- Eliana Y L Chan
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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33
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Denton D, Aung-Htut MT, Kumar S. Developmentally programmed cell death in Drosophila. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:3499-3506. [DOI: 10.1016/j.bbamcr.2013.06.014] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 06/16/2013] [Indexed: 12/24/2022]
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34
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Yuan S, Akey CW. Apoptosome structure, assembly, and procaspase activation. Structure 2013; 21:501-15. [PMID: 23561633 PMCID: PMC3644875 DOI: 10.1016/j.str.2013.02.024] [Citation(s) in RCA: 188] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2012] [Revised: 02/04/2013] [Accepted: 02/11/2013] [Indexed: 11/22/2022]
Abstract
Apaf-1-like molecules assemble into a ring-like platform known as the apoptosome. This cell death platform then activates procaspases in the intrinsic cell death pathway. In this review, crystal structures of Apaf-1 monomers and CED-4 dimers have been combined with apoptosome structures to provide insights into the assembly of cell death platforms in humans, nematodes, and flies. In humans, the caspase recognition domains (CARDs) of procaspase-9 and Apaf-1 interact with each other to form a CARD-CARD disk, which interacts with the platform to create an asymmetric proteolysis machine. The disk tethers multiple pc-9 catalytic domains to the platform to raise their local concentration, and this leads to zymogen activation. These findings have now set the stage for further studies of this critical activation process on the apoptosome.
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Affiliation(s)
- Shujun Yuan
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA
| | - Christopher W. Akey
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA
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35
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Huang J, Lv C, Hu M, Zhong G. The mitochondria-mediate apoptosis of Lepidopteran cells induced by azadirachtin. PLoS One 2013; 8:e58499. [PMID: 23516491 PMCID: PMC3596413 DOI: 10.1371/journal.pone.0058499] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2011] [Accepted: 02/07/2013] [Indexed: 01/31/2023] Open
Abstract
Mitochondria have been shown to play an important role in apoptosis using mammalian cell lines. However, this seems not to be the case in Drosophila, an insect model organism; thus more in-depth studies of insect cell apoptosis are necessary. In the present study, mitochondrial involvement during azadirachtin- and camptothecin-induced apoptosis in Spodoptera frugiperda Sf9 cells (isolated from Spodoptera frugiperda pupal ovarian tissue) was investigated. The results showed that both azadirachtin and camptothecin could induce apoptosis in Sf9 cells. Reactive oxygen species (ROS) generation, activation of mitochondrial permeability transition pores (MPTPs) and loss of mitochondrial membrane potential (MMP) were observed very early during apoptosis and were followed subsequently by the release of cytochrome-c from the mitochondria. Furthermore, the results also revealed that the opening of MPTPs and the loss of MMP induced by azadirachtin could be significantly inhibited by the permeability transition pore (PTP) inhibitor cyclosporin A (CsA), which was used to identify the key role of mitochondria in the apoptosis of Sf9 cells. However, in camptothecin-treated Sf9 cells, CsA could not suppress the opening of MPTPs and the loss of MMP when apoptosis was induced. The data from caspase-3 and caspase-9 activity assays and detection of apoptosis by morphological observation and flow cytometry also uncovered the different effect of CsA on the two botanical apoptosis inducers. Although different mechanisms of apoptosis induction exist, our study revealed that mitochondria play a crucial role in insect cell line apoptosis.
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Affiliation(s)
- Jingfei Huang
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Laboratory of Insect Toxicology, South China Agricultural University, Guangzhou, P.R. China
| | - Chaojun Lv
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Laboratory of Insect Toxicology, South China Agricultural University, Guangzhou, P.R. China
- Institute of Coconut, Chinese Academy of Tropical Agricultural Sciences, Wenchang, Hainan Province, China
| | - Meiying Hu
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Laboratory of Insect Toxicology, South China Agricultural University, Guangzhou, P.R. China
| | - Guohua Zhong
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Laboratory of Insect Toxicology, South China Agricultural University, Guangzhou, P.R. China
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36
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Abstract
The caspases, a family of cysteine proteases, function as central regulators of cell death. Recently, caspase activity and caspase substrates identified in the absence of cell death have sparked strong interest in caspase functions in nonapoptotic cellular responses; these functions suggest that caspases may be activated without inducing or before apoptosis, thus leading to the cleavage of a specific subset of substrates. This review focuses primarily on the caspase enzymatic activity. Detailed genetic analyses of caspase-deficient Caenorhabditis elegans, Drosophila, and mice have shown that caspases are essential, not only for controlling the number of cells involved in sculpting or deleting structures in developing animals, but also for dynamic, nonapoptotic cell processes, such as innate immune response, tissue regeneration, cell-fate determination, stem-cell differentiation and neural activation. Our understanding of the spatio-temporal caspase activation mechanisms has advanced, primarily through the study of Drosophila developmental processes. This review will discuss current findings regarding caspase functions in cytoskeletal modification, morphogenetic regulation of cell shape, cell migration and the production of mechanical force during embryogenesis.
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Affiliation(s)
- Erina Kuranaga
- Laboratory for Histogenetic Dynamics, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan
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37
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Liu K, Shu D, Song N, Gai Z, Yuan Y, Li J, Li M, Guo S, Peng J, Hong H. The role of cytochrome c on apoptosis induced by Anagrapha falcifera multiple nuclear polyhedrosis virus in insect Spodoptera litura cells. PLoS One 2012; 7:e40877. [PMID: 22952575 PMCID: PMC3429461 DOI: 10.1371/journal.pone.0040877] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Accepted: 06/17/2012] [Indexed: 12/12/2022] Open
Abstract
There are conflicting reports on the role of cytochrome c during insect apoptosis. Our previous studies have showed that cytochrome c released from the mitochondria was an early event by western blot analysis and caspase-3 activation was closely related to cytochrome c release during apoptosis induced by baculovirus in Spodoptera litura cells (Sl-1 cell line). In the present study, alteration in mitochondrial morphology was observed by transmission electron microscopy, and cytochrome c release from mitochondria in apoptotic Sl-1 cells induced with Anagrapha falcifera multiple nuclear polyhedrosis virus (AfMNPV) has further been confirmed by immunofluoresence staining protocol, suggesting that structural disruption of mitochondria and the release of cytochrome c are important events during Lepidoptera insect cell apoptosis. We also used Sl-1 cell-free extract system and the technique of RNA interference to further investigate the role of cytochrome c in apoptotic Sl-1 cells induced by AfMNPV. Caspase-3 activity in cell- free extracts supplemented with exogenous cytochrome c was determined and showed an increase with the extension of incubation time. DsRNA-mediated silencing of cytochrome c resulted in the inhibition of apoptosis and protected the cells from AfMNPV-induced cell death. Silencing of expression of cytochrome c had a remarkable effect on pro-caspase-3 and pro-caspase-9 activation and resulted in the reduction of caspase-3 and caspase-9 activity in Sl-1 cells undergoing apoptosis. Caspase-9 inhibitor could inhibit activation of pro-caspase-3, and the inhibition of the function of Apaf-1 with FSBA blocked apoptosis, hinting that Apaf-1 could be involved in Sl-1 cell apoptosis induced by AfMNPV. Taken together, these results strongly demonstrate that cytochrome c plays an important role in apoptotic signaling pathways in Lepidopteran insect cells.
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Affiliation(s)
- Kaiyu Liu
- Institute of Entomology, Central China Normal University, Wuhan, People's Republic of China
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, Central China Normal University, Wuhan, People's Republic of China
| | - Duanyang Shu
- Institute of Entomology, Central China Normal University, Wuhan, People's Republic of China
| | - Na Song
- Institute of Entomology, Central China Normal University, Wuhan, People's Republic of China
| | - Zhongchao Gai
- Institute of Entomology, Central China Normal University, Wuhan, People's Republic of China
| | - Yuan Yuan
- Institute of Entomology, Central China Normal University, Wuhan, People's Republic of China
| | - Juan Li
- Institute of Entomology, Central China Normal University, Wuhan, People's Republic of China
| | - Min Li
- Institute of Entomology, Central China Normal University, Wuhan, People's Republic of China
| | - Shuying Guo
- Institute of Entomology, Central China Normal University, Wuhan, People's Republic of China
| | - Jianxin Peng
- Institute of Entomology, Central China Normal University, Wuhan, People's Republic of China
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, Central China Normal University, Wuhan, People's Republic of China
- * E-mail:
| | - Huazhu Hong
- Institute of Entomology, Central China Normal University, Wuhan, People's Republic of China
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, Central China Normal University, Wuhan, People's Republic of China
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38
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Debattisti V, Scorrano L. D. melanogaster, mitochondria and neurodegeneration: small model organism, big discoveries. Mol Cell Neurosci 2012; 55:77-86. [PMID: 22940086 DOI: 10.1016/j.mcn.2012.08.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 08/10/2012] [Accepted: 08/15/2012] [Indexed: 10/28/2022] Open
Abstract
In developed countries, increased life expectancy is accompanied by an increased prevalence of age-related disorders like cancer and neurodegenerative diseases. Albeit the molecular mechanisms behind the clinically, pathologically and etiologically heterogeneous forms of neurodegeneration are often unclear, impairment of mitochondrial fusion-fission and dynamics emerged in recent years as a feature of neuronal dysfunction and death, pinpointing the need for animal models to investigate the relationship between mitochondrial shape and neurodegeneration. While research on mammalian models is slowed down by the complexity of the organisms and their genomes, the long latency of the symptoms and by the difficulty to generate and analyze large cohorts, the lower metazoan Drosophila melanogaster overcomes these problems, proving to be a suitable model to study neurodegenerative diseases and mitochondria-shaping proteins. Here we will summarize our current knowledge on the link between mitochondrial shape and models of neurodegeneration in the fruitfly. This article is part of a Special Issue entitled 'Mitochondrial function and dysfunction in neurodegeneration'.
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Affiliation(s)
- Valentina Debattisti
- Dulbecco-Telethon Institute, Venetian Institute of Molecular Medicine, Via Orus 2 35129 Padova, Italy
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39
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Park JH, Wang Z, Jeong HJ, Park HH, Kim BG, Tan WS, Choi SS, Park TH. Enhancement of recombinant human EPO production and glycosylation in serum-free suspension culture of CHO cells through expression and supplementation of 30Kc19. Appl Microbiol Biotechnol 2012; 96:671-83. [DOI: 10.1007/s00253-012-4203-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 05/18/2012] [Accepted: 05/21/2012] [Indexed: 11/29/2022]
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40
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Reubold TF, Eschenburg S. A molecular view on signal transduction by the apoptosome. Cell Signal 2012; 24:1420-5. [PMID: 22446004 DOI: 10.1016/j.cellsig.2012.03.007] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 03/05/2012] [Indexed: 12/22/2022]
Abstract
Apoptosomes are signaling platforms that initiate the dismantling of a cell during apoptosis. In mammals, assembly of the apoptosome is the pivotal point in the mitochondrial pathway of apoptosis, and is prompted by binding of cytochrome c to the apoptotic protease-activating factor 1 (Apaf-1) in the presence of ATP. The resulting wheel-like heptamer of seven molecules Apaf-1 and seven molecules cytochrome c binds and activates the initiator caspase-9, which in turn ignites the downstream caspase cascade. In this review we discuss the molecular determinants for the formation of the mammalian apoptosome and caspase activation and describe the related signaling platforms in flies and nematodes.
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Affiliation(s)
- Thomas F Reubold
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
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41
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Abstract
The mitochondrial pathway of apoptosis is the major mechanism of physiological cell death in vertebrates. In this pathway, proapoptotic members of the Bcl-2 family cause mitochondrial outer membrane permeabilization (MOMP), allowing the release of cytochrome c, which interacts with Apaf-1 to trigger caspase activation and apoptosis. Despite conservation of Bcl-2, Apaf-1, and caspases in invertebrate phyla, the existence of the mitochondrial pathway in any invertebrate is, at best, controversial. Here we show that apoptosis in a lophotrochozoan, planaria (phylum Platyhelminthes), is associated with MOMP and that cytochrome c triggers caspase activation in cytosolic extracts from these animals. Further, planarian Bcl-2 family proteins can induce and/or regulate cell death in yeast and can replace Bcl-2 proteins in mammalian cells to regulate MOMP. These results suggest that the mitochondrial pathway of apoptosis in animals predates the emergence of the vertebrates but was lost in some lineages (e.g., nematodes). In further support of this hypothesis, we surveyed the ability of cytochrome c to trigger caspase activation in cytosolic extracts from a variety of organisms and found this effect in cytosolic extracts from invertebrate deuterostomes (phylum Echinodermata).
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Saleh M. The machinery of Nod-like receptors: refining the paths to immunity and cell death. Immunol Rev 2011; 243:235-46. [DOI: 10.1111/j.1600-065x.2011.01045.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Abstract
The caspases are a family of cysteine proteases that function as central regulators of cell death. Recent investigations in Caenorhabditis elegans, Drosophila, and mice indicate that caspases are essential not only in controlling the number of cells involved in sculpting or deleting structures in developing animals, but also in dynamic cell processes such as cell-fate determination, compensatory proliferation of neighboring cells, and actin cytoskeleton reorganization, in a non-apoptotic context during development. This review focuses primarily on caspase functions involving their enzymatic activity.
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Affiliation(s)
- Erina Kuranaga
- Laboratory for Histogenetic Dynamics, RIKEN Center for Developmental Biology, Kobe, 650-0047, Japan.
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Wang H, Clem RJ. The role of IAP antagonist proteins in the core apoptosis pathway of the mosquito disease vector Aedes aegypti. Apoptosis 2011; 16:235-48. [PMID: 21274634 DOI: 10.1007/s10495-011-0575-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
While apoptosis regulation has been studied extensively in Drosophila melanogaster, similar studies in other insects, including disease vectors, lag far behind. In D. melanogaster, the inhibitor of apoptosis (IAP) protein DIAP1 is the major negative regulator of caspases, while IAP antagonists induce apoptosis, in part, by binding to DIAP1 and inhibiting its ability to regulate caspases. In this study, we characterized the roles of two IAP antagonists, Michelob_x (Mx) and IMP, in apoptosis in the yellow fever mosquito Aedes aegypti. Overexpression of Mx or IMP caused apoptosis in A. aegypti Aag2 cells, while silencing expression of mx or imp attenuated apoptosis. Addition of recombinant Mx or IMP, but not cytochrome c, to Aag2 cytosolic extract caused caspase activation. Consistent with this finding, AeIAP1 bound and inhibited both initiator and effector caspases from A. aegypti, and Mx and IMP competed with caspases for binding to AeIAP1. However, a difference was observed in the BIR domains responsible for Dronc binding by AeIAP1 versus DIAP1. These findings demonstrate that the mechanisms by which IAP antagonists regulate apoptosis are largely conserved between A. aegypti and D. melanogaster, although subtle differences exist.
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Affiliation(s)
- Hua Wang
- Molecular, Cellular, and Developmental Biology Program, Arthropod Genomics Center, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
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Courtiade J, Pauchet Y, Vogel H, Heckel DG. A comprehensive characterization of the caspase gene family in insects from the order Lepidoptera. BMC Genomics 2011; 12:357. [PMID: 21740565 PMCID: PMC3141678 DOI: 10.1186/1471-2164-12-357] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 07/08/2011] [Indexed: 11/22/2022] Open
Abstract
Background The cell suicide pathway of apoptosis is a necessary event in the life of multicellular organisms. It is involved in many biological processes ranging from development to the immune response. Evolutionarily conserved proteases, called caspases, play a central role in regulating apoptosis. Reception of death stimuli triggers the activation of initiator caspases, which in turn activate the effector caspases. In Lepidoptera, apoptosis is crucial in processes such as metamorphosis or defending against baculovirus infection. The discovery of p35, a baculovirus protein inhibiting caspase activity, has led to the characterization of the first lepidopteran caspase, Sf-Caspase-1. Studies on Sf-Caspase-1 mode of activation suggested that apoptosis in Lepidoptera requires a cascade of caspase activation, as demonstrated in many other species. Results In order to get insights into this gene family in Lepidoptera, we performed an extensive survey of lepidopteran-derived EST datasets. We identified 66 sequences distributed among 27 species encoding putative caspases. Phylogenetic analyses showed that Lepidoptera possess at least 5 caspases, for which we propose a unified nomenclature. According to homology to their Drosophila counterparts and their primary structure, we determined that Lep-Caspase-1, -2 and -3 are putative effector caspases, whereas Lep-Caspase-5 and -6 are putative initiators. The likely function of Lep-Caspase-4 remains unclear. Lep-Caspase-2 is absent from the silkworm genome and appears to be noctuid-specific, and to have arisen from a tandem duplication of the Caspase-1 gene. In the tobacco hawkmoth, 3 distinct transcripts encoding putative Caspase-4 were identified, suggesting at least 2 duplication events in this species. Conclusions The basic repertoire of five major types of caspases shared among Lepidoptera seems to be smaller than for most other groups studied to date, but gene duplication still plays a role in lineage-specific increases in diversity, just as in Diptera and mammals.
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Affiliation(s)
- Juliette Courtiade
- Department of Entomology, Max Planck Institute for Chemical Ecology, Jena, Germany
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Affiliation(s)
- Shawn B Bratton
- Division of Pharmacology and Toxicology, College of Pharmacy, and Center for Molecular and Cellular Toxicology, and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712-0125, USA.
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Abstract
In this issue of Structure, Yuan et al. (2011) utilize biochemical approaches to reconstitute an active Drosophila apoptosome, as well as cryo-electron microscopy to generate an improved model for this conserved caspase-activating complex.
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Yuan S, Yu X, Topf M, Dorstyn L, Kumar S, Ludtke SJ, Akey CW. Structure of the Drosophila apoptosome at 6.9 å resolution. Structure 2011; 19:128-40. [PMID: 21220123 DOI: 10.1016/j.str.2010.10.009] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 09/26/2010] [Accepted: 10/01/2010] [Indexed: 11/19/2022]
Abstract
The Drosophila Apaf-1 related killer forms an apoptosome in the intrinsic cell death pathway. In this study we show that Dark forms a single ring when initiator procaspases are bound. This Dark-Dronc complex cleaves DrICE efficiently; hence, a single ring represents the Drosophila apoptosome. We then determined the 3D structure of a double ring at ∼6.9 Å resolution and created a model of the apoptosome. Subunit interactions in the Dark complex are similar to those in Apaf-1 and CED-4 apoptosomes, but there are significant differences. In particular, Dark has "lost" a loop in the nucleotide-binding pocket, which opens a path for possible dATP exchange in the apoptosome. In addition, caspase recruitment domains (CARDs) form a crown on the central hub of the Dark apoptosome. This CARD geometry suggests that conformational changes will be required to form active Dark-Dronc complexes. When taken together, these data provide insights into apoptosome structure, function, and evolution.
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Affiliation(s)
- Shujun Yuan
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA
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Mitochondrial fusion is regulated by Reaper to modulate Drosophila programmed cell death. Cell Death Differ 2011; 18:1640-50. [PMID: 21475305 PMCID: PMC3172116 DOI: 10.1038/cdd.2011.26] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
In most multicellular organisms, the decision to undergo programmed cell death in response to cellular damage or developmental cues is typically transmitted through mitochondria. It has been suggested that an exception is the apoptotic pathway of Drosophila melanogaster, in which the role of mitochondria remains unclear. Although IAP antagonists in Drosophila such as Reaper, Hid and Grim may induce cell death without mitochondrial membrane permeabilization, it is surprising that all three localize to mitochondria. Moreover, induction of Reaper and Hid appears to result in mitochondrial fragmentation during Drosophila cell death. Most importantly, disruption of mitochondrial fission can inhibit Reaper and Hid-induced cell death, suggesting that alterations in mitochondrial dynamics can modulate cell death in fly cells. We report here that Drosophila Reaper can induce mitochondrial fragmentation by binding to and inhibiting the pro-fusion protein MFN2 and its Drosophila counterpart dMFN/Marf. Our in vitro and in vivo analyses reveal that dMFN overexpression can inhibit cell death induced by Reaper or γ-irradiation. In addition, knockdown of dMFN causes a striking loss of adult wing tissue and significant apoptosis in the developing wing discs. Our findings are consistent with a growing body of work describing a role for mitochondrial fission and fusion machinery in the decision of cells to die.
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Mitochondrial fission/fusion dynamics and apoptosis. Mitochondrion 2010; 10:640-8. [DOI: 10.1016/j.mito.2010.08.005] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 08/04/2010] [Accepted: 08/04/2010] [Indexed: 11/18/2022]
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