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1.
Cell ; 187(9): 2117-2119, 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38670068

RESUMO

While some people pore over the textbook and train through the classics of the field, many scientists come to immunology when they discover it intersecting with their "first love" interests. Five of these "accidental immunologists" tell us how they found their way to a fascination with the immune system.


Assuntos
Alergia e Imunologia , Humanos , História do Século XX , História do Século XXI , Animais , Sistema Imunitário
2.
Nat Rev Mol Cell Biol ; 24(10): 732-748, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37438560

RESUMO

The proteins of the BCL-2 family are key regulators of mitochondrial apoptosis, acting as either promoters or inhibitors of cell death. The functional interplay and balance between the opposing BCL-2 family members control permeabilization of the outer mitochondrial membrane, leading to the release of activators of the caspase cascade into the cytosol and ultimately resulting in cell death. Despite considerable research, our knowledge about the mechanisms of the BCL-2 family of proteins remains insufficient, which complicates cell fate predictions and does not allow us to fully exploit these proteins as targets for drug discovery. Detailed understanding of the formation and molecular architecture of the apoptotic pore in the outer mitochondrial membrane remains a holy grail in the field, but new studies allow us to begin constructing a structural model of its arrangement. Recent literature has also revealed unexpected activities for several BCL-2 family members that challenge established concepts of how they regulate mitochondrial permeabilization. In this Review, we revisit the most important advances in the field and integrate them into a new structure-function-based classification of the BCL-2 family members that intends to provide a comprehensive model for BCL-2 action in apoptosis. We close this Review by discussing the potential of drugging the BCL-2 family in diseases characterized by aberrant apoptosis.


Assuntos
Apoptose , Proteínas Proto-Oncogênicas c-bcl-2 , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Apoptose/fisiologia , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Caspases/metabolismo
3.
Mol Cell ; 83(6): 843-856, 2023 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-36931255

RESUMO

Mitochondria are cellular organelles with a major role in many cellular processes, including not only energy production, metabolism, and calcium homeostasis but also regulated cell death and innate immunity. Their proteobacterial origin makes them a rich source of potent immune agonists, normally hidden within the mitochondrial membrane barriers. Alteration of mitochondrial permeability through mitochondrial pores thus provides efficient mechanisms not only to communicate mitochondrial stress to the cell but also as a key event in the integration of cellular responses. In this regard, eukaryotic cells have developed diverse signaling networks that sense and respond to the release of mitochondrial components into the cytosol and play a key role in controlling cell death and inflammatory pathways. Modulating pore formation at mitochondria through direct or indirect mechanisms may thus open new opportunities for therapy. In this review, we discuss the current understanding of the structure and molecular mechanisms of mitochondrial pores and how they function at the interface between cell death and inflammatory signaling to regulate cellular outcomes.


Assuntos
Mitocôndrias , Membranas Mitocondriais , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Apoptose/fisiologia , Morte Celular , Transdução de Sinais
4.
Mol Cell ; 82(5): 933-949.e9, 2022 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-35120587

RESUMO

BAX and BAK are key apoptosis regulators that mediate the decisive step of mitochondrial outer membrane permeabilization. However, the mechanism by which they assemble the apoptotic pore remains obscure. Here, we report that BAX and BAK present distinct oligomerization properties, with BAK organizing into smaller structures with faster kinetics than BAX. BAK recruits and accelerates BAX assembly into oligomers that continue to grow during apoptosis. As a result, BAX and BAK regulate each other as they co-assemble into the same apoptotic pores, which we visualize. The relative availability of BAX and BAK molecules thereby determines the growth rate of the apoptotic pore and the relative kinetics by which mitochondrial contents, most notably mtDNA, are released. This feature of BAX and BAK results in distinct activation kinetics of the cGAS/STING pathway with implications for mtDNA-mediated paracrine inflammatory signaling.


Assuntos
DNA Mitocondrial , Mitocôndrias , Proteína Killer-Antagonista Homóloga a bcl-2/metabolismo , Proteína X Associada a bcl-2/metabolismo , Animais , Apoptose/genética , Linhagem Celular Tumoral , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Humanos , Inflamação/genética , Inflamação/metabolismo , Mitocôndrias/genética , Mitocôndrias/metabolismo , Multimerização Proteica , Proteína Killer-Antagonista Homóloga a bcl-2/genética , Proteína X Associada a bcl-2/genética
5.
Nat Rev Mol Cell Biol ; 21(10): 564-565, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32699359
6.
EMBO J ; 41(8): e108587, 2022 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-35023587

RESUMO

The apoptotic executioner protein BAX and the dynamin-like protein DRP1 co-localize at mitochondria during apoptosis to mediate mitochondrial permeabilization and fragmentation. However, the molecular basis and functional consequences of this interplay remain unknown. Here, we show that BAX and DRP1 physically interact, and that this interaction is enhanced during apoptosis. Complex formation between BAX and DRP1 occurs exclusively in the membrane environment and requires the BAX N-terminal region, but also involves several other BAX surfaces. Furthermore, the association between BAX and DRP1 enhances the membrane activity of both proteins. Forced dimerization of BAX and DRP1 triggers their activation and translocation to mitochondria, where they induce mitochondrial remodeling and permeabilization to cause apoptosis even in the absence of apoptotic triggers. Based on this, we propose that DRP1 can promote apoptosis by acting as noncanonical direct activator of BAX through physical contacts with its N-terminal region.


Assuntos
Apoptose , Dinaminas , Apoptose/fisiologia , Dinaminas/genética , Dinaminas/metabolismo , Mitocôndrias/metabolismo , Proteína X Associada a bcl-2/genética , Proteína X Associada a bcl-2/metabolismo
7.
EMBO J ; 41(2): e108690, 2022 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-34931711

RESUMO

During apoptosis, the BCL-2-family protein tBID promotes mitochondrial permeabilization by activating BAX and BAK and by blocking anti-apoptotic BCL-2 members. Here, we report that tBID can also mediate mitochondrial permeabilization by itself, resulting in release of cytochrome c and mitochondrial DNA, caspase activation and apoptosis even in absence of BAX and BAK. This previously unrecognized activity of tBID depends on helix 6, homologous to the pore-forming regions of BAX and BAK, and can be blocked by pro-survival BCL-2 proteins. Importantly, tBID-mediated mitochondrial permeabilization independent of BAX and BAK is physiologically relevant for SMAC release in the immune response against Shigella infection. Furthermore, it can be exploited to kill leukaemia cells with acquired venetoclax resistance due to lack of active BAX and BAK. Our findings define tBID as an effector of mitochondrial permeabilization in apoptosis and provide a new paradigm for BCL-2 proteins, with implications for anti-bacterial immunity and cancer therapy.


Assuntos
Apoptose , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/metabolismo , Proteínas Reguladoras de Apoptose/metabolismo , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/química , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/genética , Células HCT116 , Células HeLa , Humanos , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Domínios Proteicos , Proteólise , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteína Killer-Antagonista Homóloga a bcl-2/metabolismo , Proteína X Associada a bcl-2/metabolismo
8.
J Cell Sci ; 136(22)2023 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-37994778

RESUMO

The proteins of the BCL-2 family are known as key regulators of apoptosis, with interactions between family members determining permeabilisation of the mitochondrial outer membrane (MOM) and subsequent cell death. However, the exact mechanism through which they form the apoptotic pore responsible for MOM permeabilisation (MOMP), the structure and specific components of this pore, and what roles BCL-2 proteins play outside of directly regulating MOMP are incompletely understood. Owing to the link between apoptosis dysregulation and disease, the BCL-2 proteins are important targets for drug development. With the development and clinical use of drugs targeting BCL-2 proteins showing success in multiple haematological malignancies, enhancing the efficacy of these drugs, or indeed developing novel drugs targeting BCL-2 proteins is of great interest to treat cancer patients who have developed resistance or who suffer other disease types. Here, we review our current understanding of the molecular mechanism of MOMP, with a particular focus on recently discovered roles of BCL-2 proteins in apoptosis and beyond, and discuss what implications these functions might have in both healthy tissues and disease.


Assuntos
Membranas Mitocondriais , Proteínas Proto-Oncogênicas c-bcl-2 , Humanos , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteína X Associada a bcl-2/química , Membranas Mitocondriais/metabolismo , Apoptose/fisiologia
9.
EMBO J ; 39(23): e105753, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33124082

RESUMO

The discovery of alternative signaling pathways that regulate cell death has revealed multiple strategies for promoting cell death with diverse consequences at the tissue and organism level. Despite the divergence in the molecular components involved, membrane permeabilization is a common theme in the execution of regulated cell death. In apoptosis, the permeabilization of the outer mitochondrial membrane by BAX and BAK releases apoptotic factors that initiate the caspase cascade and is considered the point of no return in cell death commitment. Pyroptosis and necroptosis also require the perforation of the plasma membrane at the execution step, which involves Gasdermins in pyroptosis, and MLKL in the case of necroptosis. Although BAX/BAK, Gasdermins and MLKL share certain molecular features like oligomerization, they form pores in different cellular membranes via distinct mechanisms. Here, we compare and contrast how BAX/BAK, Gasdermins, and MLKL alter membrane permeability from a structural and biophysical perspective and discuss the general principles of membrane permeabilization in the execution of regulated cell death.


Assuntos
Morte Celular/imunologia , Morte Celular/fisiologia , Morte Celular Regulada/imunologia , Morte Celular Regulada/fisiologia , Animais , Apoptose/fisiologia , Autofagia/fisiologia , Caspases/metabolismo , Membrana Celular/metabolismo , Permeabilidade da Membrana Celular , Humanos , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Necroptose/fisiologia , Proteínas Quinases/metabolismo , Piroptose/fisiologia , Transdução de Sinais/fisiologia
10.
Genes Dev ; 30(8): 878-80, 2016 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-27083995

RESUMO

The minimum requirement for mitochondrial apoptosis has been controversial ever since the discovery of BCL-2 as a cell death regulator. In this issue ofGenes&Development, O'Neill and colleagues (pp. 973-988) end a long-standing debate by creating a cellular system free of BCL-2 family proteins, thereby identifying the outer mitochondrial membrane rather than BH3-only proteins as the only requirement for BAX/BAK activation and mitochondrial outer membrane permeabilization (MOMP).


Assuntos
Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Membranas Mitocondriais/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteína Killer-Antagonista Homóloga a bcl-2/genética , Proteína X Associada a bcl-2/genética , Apoptose/genética , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Sistemas CRISPR-Cas , Humanos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Modelos Biológicos , Permeabilidade , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteína Killer-Antagonista Homóloga a bcl-2/metabolismo , Proteína X Associada a bcl-2/metabolismo
11.
J Phys Chem A ; 127(15): 3490-3496, 2023 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-37023388

RESUMO

Single molecule fluorescence microscopy has the unique advantage to provide real-time information on the spatiotemporal assembly of individual protein complexes in cellular membranes. This includes the assembly of proteins into oligomer species of numerous copy numbers. However, there is a need for improved tracing analysis of the real-time growth kinetics of these assemblies in cells with single molecule resolution. Here, we present an automated analysis software to accurately measure the real-time kinetics of assembly of individual high-order oligomer complexes. Our software comes with a simple Graphical User Interface (GUI), is available as a source code and an executable, and can analyze a full data set of several hundred to thousand molecules in less than 2 minutes. Importantly, this software is suitable for the analysis of intracellular protein oligomers, whose stoichiometry is usually more difficult to quantify due to variability in signal detection in the different areas of the cell. We validated our method with simulated ground-truth data and time-lapse images of diffraction-limited oligomeric assemblies of BAX and BAK proteins on mitochondria of cells undergoing apoptosis. Our approach provides the broad community of biologists with a fast, user-friendly tool to trace the compositional evolution of macromolecular assemblies, and potentially model their growth for a deeper understanding of the structural and biophysical mechanisms underlying their functions.


Assuntos
Software , Cinética
12.
Cell Mol Life Sci ; 79(6): 284, 2022 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-35526196

RESUMO

BACKGROUND AND AIMS: Recent evidences highlight a role of the mitochondria calcium homeostasis in the development of colorectal cancer (CRC). To overcome treatment resistance, we aimed to evaluate the role of the mitochondrial sodium-calcium-lithium exchanger (NCLX) and its targeting in CRC. We also identified curcumin as a new inhibitor of NCLX. METHODS: We examined whether curcumin and pharmacological compounds induced the inhibition of NCLX-mediated mitochondrial calcium (mtCa2+) extrusion, the role of redox metabolism in this process. We evaluated their anti-tumorigenic activity in vitro and in a xenograft mouse model. We analyzed NCLX expression and associations with survival in The Cancer Genome Atlas (TCGA) dataset and in tissue microarrays from 381 patients with microsatellite instability (MSI)-driven CRC. RESULTS: In vitro, curcumin exerted strong anti-tumoral activity through its action on NCLX with mtCa2+ and reactive oxygen species overload associated with a mitochondrial membrane depolarization, leading to reduced ATP production and apoptosis. NCLX inhibition with pharmacological and molecular approaches reproduced the effects of curcumin. NCLX inhibitors decreased CRC tumor growth in vivo. Both transcriptomic analysis of TCGA dataset and immunohistochemical analysis of tissue microarrays demonstrated that higher NCLX expression was associated with MSI status, and for the first time, NCLX expression was significantly associated with recurrence-free survival. CONCLUSIONS: Our findings highlight a novel anti-tumoral mechanism of curcumin through its action on NCLX and mitochondria calcium overload that could benefit for therapeutic schedule of patients with MSI CRC.


Assuntos
Neoplasias Colorretais , Curcumina , Instabilidade de Microssatélites , Trocador de Sódio e Cálcio , Animais , Cálcio/metabolismo , Sinalização do Cálcio , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Curcumina/farmacologia , Humanos , Camundongos , Repetições de Microssatélites , Proteínas Mitocondriais/metabolismo , Trocador de Sódio e Cálcio/antagonistas & inibidores
13.
Proc Natl Acad Sci U S A ; 117(50): 31871-31881, 2020 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-33257567

RESUMO

TAT-RasGAP317-326 is a cell-penetrating peptide-based construct with anticancer and antimicrobial activities. This peptide kills a subset of cancer cells in a manner that does not involve known programmed cell death pathways. Here we have elucidated the mode of action allowing TAT-RasGAP317-326 to kill cells. This peptide binds and disrupts artificial membranes containing lipids typically enriched in the inner leaflet of the plasma membrane, such as phosphatidylinositol-bisphosphate (PIP2) and phosphatidylserine (PS). Decreasing the amounts of PIP2 in cells renders them more resistant to TAT-RasGAP317-326, while reducing the ability of cells to repair their plasma membrane makes them more sensitive to the peptide. The W317A TAT-RasGAP317-326 point mutant, known to have impaired killing activities, has reduced abilities to bind and permeabilize PIP2- and PS-containing membranes and to translocate through biomembranes, presumably because of a higher propensity to adopt an α-helical state. This work shows that TAT-RasGAP317-326 kills cells via a form of necrosis that relies on the physical disruption of the plasma membrane once the peptide targets specific phospholipids found on the cytosolic side of the plasma membrane.


Assuntos
Morte Celular/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Proteínas Ativadoras de GTPase/farmacologia , Fragmentos de Peptídeos/farmacologia , Fosfatidilinositol 4,5-Difosfato/metabolismo , Fosfatidilserinas/metabolismo , Animais , Células CHO , Membrana Celular/metabolismo , Membrana Celular/ultraestrutura , Cricetulus , Proteínas Ativadoras de GTPase/uso terapêutico , Células HeLa , Humanos , Lipossomos/metabolismo , Lipossomos/ultraestrutura , Microscopia Eletrônica , Simulação de Dinâmica Molecular , Neoplasias/tratamento farmacológico , Ressonância Magnética Nuclear Biomolecular , Fragmentos de Peptídeos/uso terapêutico
14.
Angew Chem Int Ed Engl ; 62(18): e202219050, 2023 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-36735334

RESUMO

Self-labeling enzymes (SLE) such as the HaloTag have emerged as powerful tools in high and super-resolution fluorescence microscopy. Newly developed fluorogenic SLE substrates enable imaging in the presence of excess dye. To exploit this feature for reversible labeling, we engineered two variants of HaloTag7 with restored dehalogenase activity. Kinetic studies in vitro showed different turnover kinetics for reHaloTagS (≈0.006 s-1 ) and reHaloTagF (≈0.055 s-1 ). Imaging by confocal and stimulated emission depletion microscopy yielded 3-5-time enhanced photostability of reHaloTag labeling. Prominently, single molecule imaging with reHaloTags enabled controlled and stable labeling density over extended time periods. By combination with structured illumination, simultaneous visualization of single molecule diffusion and organellar dynamics was achieved. These applications highlight the potential of reHaloTag labeling for pushing the limits of advanced fluorescence microscopy techniques.


Assuntos
Corantes Fluorescentes , Corantes Fluorescentes/química , Cinética , Microscopia de Fluorescência/métodos
15.
Nat Methods ; 16(8): 711-714, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31263253

RESUMO

Super-resolution microscopy allows imaging of cellular structures with high throughput and detail. However, the efficient and quantitative analysis of images generated is challenging with existing tools. Here, we develop ASAP (automated structures analysis program) to enable rapid and automated detection, classification and quantification of super-resolved structures. We validate ASAP on ground truth data and demonstrate its broad applicability by analyzing images of nucleoporins, TORC1 complexes, endocytic vesicles and Bax pores.


Assuntos
Endossomos/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/análise , Microscopia de Fluorescência/métodos , Imagem Molecular/métodos , Complexo de Proteínas Formadoras de Poros Nucleares/análise , Vesículas Transportadoras/metabolismo , Proteína X Associada a bcl-2/análise , Humanos
16.
Bioinformatics ; 37(21): 3998-4000, 2021 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-33964131

RESUMO

MOTIVATION: Imaging single molecules has emerged as a powerful characterization tool in the biological sciences. The detection of these under various noise conditions requires the use of algorithms that are dependent on the end-user inputting several parameters, the choice of which can be challenging and subjective. RESULTS: In this work, we propose DeepSinse, an easily trainable and useable deep neural network that can detect single molecules with little human input and across a wide range of signal-to-noise ratios. We validate the neural network on the detection of single bursts in simulated and experimental data and compare its performance with the best-in-class, domain-specific algorithms. AVAILABILITYAND IMPLEMENTATION: Ground truth ROI simulating code, neural network training, validation code, classification code, ROI picker, GUI for simulating, training and validating DeepSinse as well as pre-trained networks are all released under the MIT License on www.github.com/jdanial/DeepSinse. The dSTORM dataset processing code is released under the MIT License on www.github.com/jdanial/StormProcessor. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Disciplinas das Ciências Biológicas , Aprendizado Profundo , Humanos , Redes Neurais de Computação , Algoritmos , Razão Sinal-Ruído
17.
Mol Cell ; 56(4): 496-505, 2014 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-25458844

RESUMO

Bax plays a central role in the mitochondrial pathway of apoptosis. Upon activation, cytosolic Bax monomers oligomerize on the surface of mitochondria and change conformation concertedly to punch holes into the outer membrane. The subsequent release of cytochrome c initiates cell death. However, the structure of membrane-inserted Bax and its mechanism of action remain largely unknown. Here, we propose a 3D model of active Bax at the membrane based on double electron-electron resonance (DEER) spectroscopy in liposomes and isolated mitochondria. We show that active Bax is organized at the membrane as assemblies of dimers. In addition to a stable dimerization domain, each monomer contains a more flexible piercing domain involved in interdimer interactions and pore formation. The most important structural change during Bax activation is the opening of the hairpin formed by helices 5 and 6, which adopts a clamp-like conformation central to the mechanism of mitochondrial permeabilization.


Assuntos
Membrana Celular/química , Proteína X Associada a bcl-2/química , Animais , Camundongos , Modelos Moleculares , Multimerização Proteica , Estrutura Quaternária de Proteína , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína
18.
Cell Mol Life Sci ; 78(8): 3777-3790, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33576840

RESUMO

Apoptotic cell death is essential for development, immune function or tissue homeostasis, and its mis-regulation is linked to various diseases. Mitochondrial outer membrane permeabilization (MOMP) is a central event in the intrinsic apoptotic pathway and essential to control the execution of cell death. Here we review current concepts in regulation of MOMP focusing on the interaction network of the Bcl-2 family proteins as well as further regulatory elements influencing MOMP. As MOMP is a complex spatially and temporally controlled process, we point out the importance of single-molecule techniques to unveil processes which would be masked by ensemble measurements. We report key single-molecule studies applied to decipher the composition, assembly mechanism and structure of protein complexes involved in MOMP regulation.


Assuntos
Apoptose , Mitocôndrias/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Animais , Transferência Ressonante de Energia de Fluorescência/métodos , Humanos , Impressão Molecular/métodos , Permeabilidade , Mapeamento de Interação de Proteínas/métodos , Mapas de Interação de Proteínas , Proteínas Proto-Oncogênicas c-bcl-2/análise
19.
J Biol Chem ; 295(6): 1623-1636, 2020 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-31901077

RESUMO

Permeabilization of the mitochondrial outer membrane is a key step in the intrinsic apoptosis pathway, triggered by the release of mitochondrial intermembrane space proteins into the cytoplasm. The BCL-2-associated X apoptosis regulator (BAX) protein critically contributes to this process by forming pores in the mitochondrial outer membrane. However, the relative roles of the mitochondrial residence of BAX and its oligomerization in promoting membrane permeabilization are unclear. To this end, using both cell-free and cellular experimental systems, including membrane permeabilization, size-exclusion chromatography-based oligomer, and retrotranslocation assays, along with confocal microscopy analysis, here we studied two BAX C-terminal variants, T182I and G179P. Neither variant formed large oligomers when activated in liposomes. Nevertheless, the G179P variant could permeabilize liposome membranes, suggesting that large BAX oligomers are not essential for the permeabilization. However, when G179P was transduced into BAX/BCL2 agonist killer (BAK) double-knockout mouse embryonic fibroblasts, its location was solely cytoplasmic, and it then failed to mediate cell death. In contrast, T182I was inefficient in both liposome insertion and permeabilization. Yet, when transduced into cells, BAXT182I resided predominantly on mitochondria, because of its slow retrotranslocation and mediated apoptosis as efficiently as WT BAX. We conclude that BAX's mitochondrial residence in vivo, regulated by both targeting and retrotranslocation, is more significant for its pro-apoptotic activity than its ability to insert and to form higher-order oligomers in model membranes. We propose that this finding should be taken into account when developing drugs that modulate BAX activity.


Assuntos
Apoptose , Bicamadas Lipídicas/metabolismo , Mitocôndrias/metabolismo , Proteína X Associada a bcl-2/metabolismo , Animais , Células Cultivadas , Técnicas de Inativação de Genes , Humanos , Camundongos , Mitocôndrias/genética , Permeabilidade , Mutação Puntual , Multimerização Proteica , Proteína X Associada a bcl-2/análise , Proteína X Associada a bcl-2/genética
20.
Biochem Soc Trans ; 49(2): 663-674, 2021 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-33704419

RESUMO

Mitochondria are double-membrane bound organelles that not only provide energy for intracellular metabolism, but also play a key role in the regulation of cell death. Mitochondrial outer membrane permeabilization (MOMP), allowing the release of intermembrane space proteins like cytochrome c, is considered a point of no return in apoptosis. MOMP is controlled by the proteins of the B-cell lymphoma 2 (BCL-2) family, including pro-and anti-apoptotic members, whose balance determines the decision between cell death and survival. Other factors such as membrane lipid environment, membrane dynamics, and inter-organelle communications are also known to influence this process. MOMP and apoptosis have been acknowledged as immunologically silent. Remarkably, a growing body of evidence indicates that MOMP can engage in various pro-inflammatory signaling functions. In this mini-review, we discuss about our current knowledge on the mechanisms of mitochondrial apoptosis, as well as the involvement of mitochondria in other kinds of programmed cell death pathways.


Assuntos
Apoptose/fisiologia , Morte Celular/fisiologia , Ferroptose/fisiologia , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Piroptose/fisiologia , Animais , Humanos , Modelos Biológicos , Transdução de Sinais/fisiologia
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