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Srivastava S, Sekar G, Ojoawo A, Aggarwal A, Ferreira E, Uchikawa E, Yang M, Grace CR, Dey R, Lin YL, Guibao CD, Jayaraman S, Mukherjee S, Kossiakoff AA, Dong B, Myasnikov A, Moldoveanu T. Structural basis of BAK sequestration by MCL-1 in apoptosis. Mol Cell 2025; 85:1606-1623.e10. [PMID: 40187349 DOI: 10.1016/j.molcel.2025.03.013] [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: 07/22/2024] [Revised: 12/11/2024] [Accepted: 03/12/2025] [Indexed: 04/07/2025]
Abstract
Apoptosis controls cell fate, ensuring tissue homeostasis and promoting disease when dysregulated. The rate-limiting step in apoptosis is mitochondrial poration by the effector B cell lymphoma 2 (BCL-2) family proteins BAK and BAX, which are activated by initiator BCL-2 homology 3 (BH3)-only proteins (e.g., BIM) and inhibited by guardian BCL-2 family proteins (e.g., MCL-1). We integrated structural, biochemical, and pharmacological approaches to characterize the human prosurvival MCL-1:BAK complex assembled from their BCL-2 globular core domains. We reveal a canonical interaction with BAK BH3 bound to the hydrophobic groove of MCL-1 and disordered and highly dynamic BAK regions outside the complex interface. We predict similar conformations of activated effectors in complex with other guardians or effectors. The MCL-1:BAK complex is a major cancer drug target. We show that MCL-1 inhibitors are inefficient in neutralizing the MCL-1:BAK complex, requiring high doses to initiate apoptosis. Our study underscores the need to design superior clinical candidate MCL-1 inhibitors.
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Affiliation(s)
- Shagun Srivastava
- Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Giridhar Sekar
- Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Adedolapo Ojoawo
- Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105; Integrative Structural and Computational Biology, Scripps Research Institute, La Jolla, CA 92037, USA
| | - Anup Aggarwal
- Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105; Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Elisabeth Ferreira
- Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Emiko Uchikawa
- Dubochet Center for Imaging, EPFL, Lausanne 1015, Vaud, Switzerland
| | - Meek Yang
- Chemistry and Biochemistry, University of Arkansas Fayetteville, Fayetteville, AR 72701, USA
| | - Christy R Grace
- Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Raja Dey
- Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Yi-Lun Lin
- Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Cristina D Guibao
- Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Seetharaman Jayaraman
- Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105; Pharmacology, Addiction Science, and Toxicology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Somnath Mukherjee
- Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - Anthony A Kossiakoff
- Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - Bin Dong
- Chemistry and Biochemistry, University of Arkansas Fayetteville, Fayetteville, AR 72701, USA
| | | | - Tudor Moldoveanu
- Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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Liu D, Liu Z, Hu Y, Xiong W, Wang D, Zeng Z. MOMP: A critical event in cell death regulation and anticancer treatment. Biochim Biophys Acta Rev Cancer 2025; 1880:189280. [PMID: 39947442 DOI: 10.1016/j.bbcan.2025.189280] [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: 11/04/2024] [Revised: 01/25/2025] [Accepted: 02/04/2025] [Indexed: 02/21/2025]
Abstract
Mitochondrial outer membrane permeabilization (MOMP) refers to the increase in permeability of the mitochondrial outer membrane, allowing proteins, DNA, and other molecules to pass through the intermembrane space into the cytosol. As a crucial event in the induction of apoptosis, MOMP plays a significant role in regulating various forms of cell death, including apoptosis, ferroptosis, and pyroptosis. Importantly, MOMP is not a binary process of "all-or-nothing." Under sub-lethal stress stimuli, cells may experience a phenomenon referred to as minority MOMP (miMOMP), where only a subset of mitochondria undergo functional impairment, thereby disrupting the normal life cycle of the cell. This can lead to pathological and physiological changes such as tumor formation, cellular senescence, innate immune dysfunction, and chronic inflammation. This review focuses on the diversity of MOMP events to elucidate how varying degrees of MOMP under different stress conditions influence cell fate. Additionally, it summarizes the current research progress on novel antitumor therapeutic strategies targeting MOMP in clinical contexts.
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Affiliation(s)
- Dan Liu
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China; Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and Xiangya School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Ziqi Liu
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and Xiangya School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Yan Hu
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and Xiangya School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Wei Xiong
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and Xiangya School of Basic Medical Sciences, Central South University, Changsha, Hunan, China
| | - Dan Wang
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China; Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and Xiangya School of Basic Medical Sciences, Central South University, Changsha, Hunan, China.
| | - Zhaoyang Zeng
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China; Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and Xiangya School of Basic Medical Sciences, Central South University, Changsha, Hunan, China.
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3
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Li K, Yap YQ, Moujalled DM, Sumardy F, Khakham Y, Georgiou A, Jahja M, Lew TE, De Silva M, Luo MX, Gong JN, Yuan Z, Birkinshaw RW, Czabotar PE, Lowes K, Huang DCS, Kile BT, Wei AH, Dewson G, van Delft MF, Lessene G. Differential regulation of BAX and BAK apoptotic activity revealed by small molecules. SCIENCE ADVANCES 2025; 11:eadr8146. [PMID: 40043112 PMCID: PMC11881913 DOI: 10.1126/sciadv.adr8146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2024] [Accepted: 01/30/2025] [Indexed: 05/13/2025]
Abstract
Defective apoptosis mediated by B cell lymphoma 2 antagonist/killer (BAK) or B cell lymphoma 2-associated X protein (BAX) underlies various pathologies including autoimmune and degenerative conditions. On mitochondria, voltage-dependent anion channel 2 (VDAC2) interacts with BAK and BAX through a common interface to inhibit BAK or to facilitate BAX apoptotic activity. We identified a small molecule (WEHI-3773) that inhibits interaction between VDAC2 and BAK or BAX revealing contrasting effects on their apoptotic activity. WEHI-3773 inhibits apoptosis mediated by BAX by blocking VDAC2-mediated BAX recruitment to mitochondria. Conversely, WEHI-3773 promotes BAK-mediated apoptosis by limiting inhibitory sequestration by VDAC2. In cells expressing both pro-apoptotic proteins, apoptosis promotion by WEHI-3773 dominates, because activated BAK activates BAX through a feed-forward mechanism. Loss of BAX drives resistance to the BCL-2 inhibitor venetoclax in some leukemias. WEHI-3773 overcomes this resistance by promoting BAK-mediated killing. This work highlights the coordination of BAX and BAK apoptotic activity through interaction with VDAC2 that may be targeted therapeutically.
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Affiliation(s)
- Kaiming Li
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Yu Q. Yap
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Donia M. Moujalled
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Fransisca Sumardy
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Yelena Khakham
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Angela Georgiou
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Michelle Jahja
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Thomas E. Lew
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
- Department of Clinical Haematology, Peter MacCallum Cancer Centre and Royal Melbourne Hospital, Melbourne, Victoria, Australia
| | - Melanie De Silva
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Meng-Xiao Luo
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Jia-nan Gong
- National Human Diseases Animal Model Resource Center, National Center of Technology Innovation for Animal Model, Laboratory of Human Disease Comparative Medicine, Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Zheng Yuan
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Richard W. Birkinshaw
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Peter E. Czabotar
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Kym Lowes
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - David C. S. Huang
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Benjamin T. Kile
- Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales, Australia
| | - Andrew H. Wei
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
- Department of Clinical Haematology, Peter MacCallum Cancer Centre and Royal Melbourne Hospital, Melbourne, Victoria, Australia
| | - Grant Dewson
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Mark F. van Delft
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Guillaume Lessene
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, Victoria, Australia
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4
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Wang L, Chen Y, Zhang M, Liu J, Li H, Liu M, Wu S, Zhang Y, Li W, Wang B. Chemical dissection of selective myeloid leukemia-1 inhibitors: How they were found and evolved. Eur J Med Chem 2025; 283:117168. [PMID: 39708769 DOI: 10.1016/j.ejmech.2024.117168] [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: 08/17/2024] [Accepted: 12/11/2024] [Indexed: 12/23/2024]
Abstract
Myeloid cell leukemia-1 (MCL-1), a key anti-apoptotic protein within the BCL-2 family, is essential in regulating cell survival, particularly in cancer, where its overexpression is often linked to therapeutic resistance. This review begins with an overview of BCL-2-mediated apoptosis, highlighting the pivotal role of MCL-1 in cellular homeostasis. We then focus on the structure and function of MCL-1, elucidating how its unique structural features contribute to its function and interaction with pro-apoptotic proteins. The core of this review is a detailed structural analysis of selective MCL-1 inhibitors, tracing their development from initial discovery to stepwise optimization. We explore various classes of inhibitors, including those with distinct core structures, covalent inhibitors that reversibly/irreversibly bind to MCL-1, and innovative approaches such as metal-based inhibitors and proteolysis-targeting chimeras (PROTACs). The structural evolution of these inhibitors is discussed, with particular emphasis on the modifications that have enhanced their selectivity, potency, and pharmacokinetic profiles. Additionally, we summarize the synergistic potential of MCL-1 inhibitors when used in combination with other therapeutic agents, emphasizing their role in overcoming drug resistance. The review concludes with a discussion of current challenges in MCL-1 modulation and future perspectives, proposing alternative strategies for targeting this critical protein for cancer therapy.
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Affiliation(s)
- Luyao Wang
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Yuxiang Chen
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Maoqian Zhang
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Jin Liu
- Chia Tai Tianqing Pharmaceutical Group Co., Ltd., Nanjing 211162, China
| | - Haozhe Li
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Menghui Liu
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Shuyun Wu
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Yongmin Zhang
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China; Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, UMR 8232, 4 Place Jussieu, 75005 Paris, France; Key Laboratory of Tropical Medicinal Resource Chemistry of Ministry of Education, College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou, 571158, China; Fuyang Institute & School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 311422, Zhejiang, China.
| | - Wei Li
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China.
| | - Bo Wang
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China; State Key Laboratory on Technologies for Chinese Medicine Pharmaceutical Process Control and Intelligent Manufacture, Nanjing University of Chinese Medicine, Nanjing 210023, China.
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5
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Johnson L, Sarosiek KA. Role of intrinsic apoptosis in environmental exposure health outcomes. Trends Mol Med 2024; 30:56-73. [PMID: 38057226 DOI: 10.1016/j.molmed.2023.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 10/31/2023] [Accepted: 11/06/2023] [Indexed: 12/08/2023]
Abstract
Environmental exposures are linked to diseases of high public health concern, including cancer, neurodegenerative disorders, and autoimmunity. These diseases are caused by excessive or insufficient cell death, prompting investigation of mechanistic links between environmental toxicants and dysregulation of cell death pathways, including apoptosis. This review describes how legacy and emerging environmental exposures target the intrinsic apoptosis pathway to potentially drive pathogenesis. Recent discoveries reveal that dynamic regulation of apoptosis may heighten the vulnerability of healthy tissues to exposures in children, and that apoptotic signaling can guide immune responses, tissue repair, and tumorigenesis. Understanding how environmental toxicants dysregulate apoptosis will uncover opportunities to deploy apoptosis-modulating agents for the treatment or prevention of exposure-linked diseases.
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Affiliation(s)
- Lissah Johnson
- John B. Little Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Molecular and Integrative Physiological Sciences Program, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Laboratory for Systems Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Kristopher A Sarosiek
- John B. Little Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Molecular and Integrative Physiological Sciences Program, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Laboratory for Systems Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Medical Oncology, Dana-Farber Cancer Institute/Harvard Cancer Center, Boston, MA, USA.
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6
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Czabotar PE, Garcia-Saez AJ. Mechanisms of BCL-2 family proteins in mitochondrial apoptosis. Nat Rev Mol Cell Biol 2023; 24:732-748. [PMID: 37438560 DOI: 10.1038/s41580-023-00629-4] [Citation(s) in RCA: 223] [Impact Index Per Article: 111.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2023] [Indexed: 07/14/2023]
Abstract
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.
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Affiliation(s)
- Peter E Czabotar
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia.
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia.
| | - Ana J Garcia-Saez
- Membrane Biophysics, Institute of Genetics, CECAD, University of Cologne, Cologne, Germany.
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Flores-Romero H, Dadsena S, García-Sáez AJ. Mitochondrial pores at the crossroad between cell death and inflammatory signaling. Mol Cell 2023; 83:843-856. [PMID: 36931255 DOI: 10.1016/j.molcel.2023.02.021] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 02/13/2023] [Accepted: 02/16/2023] [Indexed: 03/18/2023]
Abstract
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.
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Affiliation(s)
- Hector Flores-Romero
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne, Germany
| | - Shashank Dadsena
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne, Germany
| | - Ana J García-Sáez
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne, Germany.
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8
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Aguilar F, Yu S, Grant RA, Swanson S, Ghose D, Su BG, Sarosiek KA, Keating AE. Peptides from human BNIP5 and PXT1 and non-native binders of pro-apoptotic BAK can directly activate or inhibit BAK-mediated membrane permeabilization. Structure 2023; 31:265-281.e7. [PMID: 36706751 PMCID: PMC9992319 DOI: 10.1016/j.str.2023.01.001] [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: 08/30/2022] [Revised: 11/24/2022] [Accepted: 01/02/2023] [Indexed: 01/27/2023]
Abstract
Apoptosis is important for development and tissue homeostasis, and its dysregulation can lead to diseases, including cancer. As an apoptotic effector, BAK undergoes conformational changes that promote mitochondrial outer membrane disruption, leading to cell death. This is termed "activation" and can be induced by peptides from the human proteins BID, BIM, and PUMA. To identify additional peptides that can regulate BAK, we used computational protein design, yeast surface display screening, and structure-based energy scoring to identify 10 diverse new binders. We discovered peptides from the human proteins BNIP5 and PXT1 and three non-native peptides that activate BAK in liposome assays and induce cytochrome c release from mitochondria. Crystal structures and binding studies reveal a high degree of similarity among peptide activators and inhibitors, ruling out a simple function-determining property. Our results shed light on the vast peptide sequence space that can regulate BAK function and will guide the design of BAK-modulating tools and therapeutics.
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Affiliation(s)
- Fiona Aguilar
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Stacey Yu
- Laboratory of Systems Pharmacology, Harvard Program in Therapeutic Science, Department of Systems Biology, Harvard Medical School, Boston, MA, USA; Program in Molecular and Integrative Physiological Sciences Program, Harvard T.H. Chan School of Public Health, Boston, MA, USA; John B. Little Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Robert A Grant
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Sebastian Swanson
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Dia Ghose
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Bonnie G Su
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kristopher A Sarosiek
- Laboratory of Systems Pharmacology, Harvard Program in Therapeutic Science, Department of Systems Biology, Harvard Medical School, Boston, MA, USA; Program in Molecular and Integrative Physiological Sciences Program, Harvard T.H. Chan School of Public Health, Boston, MA, USA; John B. Little Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Amy E Keating
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA.
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9
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Moldoveanu T. Apoptotic mitochondrial poration by a growing list of pore-forming BCL-2 family proteins. Bioessays 2023; 45:e2200221. [PMID: 36650950 PMCID: PMC9975053 DOI: 10.1002/bies.202200221] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/31/2022] [Accepted: 01/02/2023] [Indexed: 01/19/2023]
Abstract
The pore-forming BCL-2 family proteins are effectors of mitochondrial poration in apoptosis initiation. Two atypical effectors-BOK and truncated BID (tBID)-join the canonical effectors BAK and BAX. Gene knockout revealed developmental phenotypes in the absence the effectors, supporting their roles in vivo. During apoptosis effectors are activated and change shape from dormant monomers to dynamic oligomers that associate with and permeabilize mitochondria. BID is activated by proteolysis, BOK accumulates on inhibition of its degradation by the E3 ligase gp78, while BAK and BAX undergo direct activation by BH3-only initiators, autoactivation, and crossactivation. Except tBID, effector oligomers on the mitochondria appear as arcs and rings in super-resolution microscopy images. The BH3-in-groove dimers of BAK and BAX, the tBID monomers, and uncharacterized BOK species are the putative building blocks of apoptotic pores. Effectors interact with lipids and bilayers but the mechanism of membrane poration remains elusive. I discuss effector-mediated mitochondrial poration.
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Affiliation(s)
- Tudor Moldoveanu
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences,Correspondence:
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