1
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Ghorbani N, Yaghubi R, Davoodi J, Pahlavan S. How does caspases regulation play role in cell decisions? apoptosis and beyond. Mol Cell Biochem 2024; 479:1599-1613. [PMID: 37976000 DOI: 10.1007/s11010-023-04870-5] [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: 06/14/2023] [Accepted: 10/05/2023] [Indexed: 11/19/2023]
Abstract
Caspases are a family of cysteine proteases, and the key factors behind the cellular events which occur during apoptosis and inflammation. However, increasing evidence shows the non-conventional pro-survival action of apoptotic caspases in crucial processes. These cellular events include cell proliferation, differentiation, and migration, which may appear in the form of metastasis, and chemotherapy resistance in cancerous situations. Therefore, there should be a precise and strict control of caspases activity, perhaps through maintaining the threshold below the required levels for apoptosis. Thus, understanding the regulators of caspase activities that render apoptotic caspases as non-apoptotic is of paramount importance both mechanistically and clinically. Furthermore, the functions of apoptotic caspases are affected by numerous post-translational modifications. In the present mini-review, we highlight the various mechanisms that directly impact caspases with respect to their anti- or non-apoptotic functions. In this regard, post-translational modifications (PTMs), isoforms, subcellular localization, transient activity, substrate availability, substrate selection, and interaction-mediated regulations are discussed.
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Affiliation(s)
- Negar Ghorbani
- Department of Biochemistry, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Roham Yaghubi
- Department of Biotechnology, College of Science, University of Tehran, Tehran, Iran
| | - Jamshid Davoodi
- Department of Biochemistry, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.
| | - Sara Pahlavan
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran.
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2
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Sahoo G, Samal D, Khandayataray P, Murthy MK. A Review on Caspases: Key Regulators of Biological Activities and Apoptosis. Mol Neurobiol 2023; 60:5805-5837. [PMID: 37349620 DOI: 10.1007/s12035-023-03433-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 06/06/2023] [Indexed: 06/24/2023]
Abstract
Caspases are proteolytic enzymes that belong to the cysteine protease family and play a crucial role in homeostasis and programmed cell death. Caspases have been broadly classified by their known roles in apoptosis (caspase-3, caspase-6, caspase-7, caspase-8, and caspase-9 in mammals) and in inflammation (caspase-1, caspase-4, caspase-5, and caspase-12 in humans, and caspase-1, caspase-11, and caspase-12 in mice). Caspases involved in apoptosis have been subclassified by their mechanism of action as either initiator caspases (caspase-8 and caspase-9) or executioner caspases (caspase-3, caspase-6, and caspase-7). Caspases that participate in apoptosis are inhibited by proteins known as inhibitors of apoptosis (IAPs). In addition to apoptosis, caspases play a role in necroptosis, pyroptosis, and autophagy, which are non-apoptotic cell death processes. Dysregulation of caspases features prominently in many human diseases, including cancer, autoimmunity, and neurodegenerative disorders, and increasing evidence shows that altering caspase activity can confer therapeutic benefits. This review covers the different types of caspases, their functions, and their physiological and biological activities and roles in different organisms.
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Affiliation(s)
- Gayatri Sahoo
- Department of Zoology, PSSJ College, Banarpal, 759128, Odisha, India
| | - Dibyaranjan Samal
- Department of Biotechnology, Academy of Management and Information Technology (AMIT, affiliated to Utkal University), Khurda, 752057, Odisha, India
| | | | - Meesala Krishna Murthy
- Department of Allied Health Sciences, Chitkara School of Health Sciences, Chitkara University, Rajpura, Punjab, 140401, India.
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3
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Che W, Zhao M, Li X, Li C, Cho WC, Yu S. Current insights in molecular characterization of non-alcoholic fatty liver disease and treatment. Front Endocrinol (Lausanne) 2022; 13:1002916. [PMID: 36523601 PMCID: PMC9744925 DOI: 10.3389/fendo.2022.1002916] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/14/2022] [Indexed: 11/30/2022] Open
Abstract
There is a continuously rising incidence of non-alcoholic fatty liver disease (NAFLD) around the world, which parallels the increasing incidence of metabolic diseases. NAFLD is a range of liver conditions that contains simple non-alcoholic fatty liver and advanced non-alcoholic steatohepatitis. In serious cases, NAFLD may develop into cirrhosis or even liver cancer. NAFLD has an intense relationship with metabolic syndrome, type 2 diabetes mellitus. It is known that gut microbiota, and functional molecules such as adenosine monophosphate-activated protein kinase JNK, and peroxisome proliferator-activated receptors (PPARs) in progressing and treating NAFLD. Traditionally, the conventional and effective therapeutic strategy is lifestyle intervention. Nowadays, new medicines targeting specific molecules, such as farnesoid X receptor, PPARs, and GLP-1 receptor, have been discovered and shown beneficial effects on patients with NAFLD. In this article, we focus on the molecular mechanisms and therapeutic approaches to NAFLD.
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Affiliation(s)
- Wensheng Che
- Department of General Surgery, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Ming Zhao
- Chengdu Medical College, Chengdu, China
- Department of Gastroenterology, The First Affiliated Hospital of Chengdu Medical College, Chengdu, China
| | - Xiaoqing Li
- Department of Pathology, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Chunlong Li
- Department of General Surgery, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - William C. Cho
- Department of Clinical Oncology, Queen Elizabeth Hospital, Kowloon, Hong Kong SAR, China
| | - Shan Yu
- Department of Pathology, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
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4
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Horbowicz-Drożdżal P, Kamel K, Kmiecik S, Borkiewicz L, Tumer NE, Shaw PC, Tchórzewski M, Grela P. Phosphorylation of the conserved C-terminal domain of ribosomal P-proteins impairs the mode of interaction with plant toxins. FEBS Lett 2021; 595:2221-2236. [PMID: 34328639 DOI: 10.1002/1873-3468.14170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 07/14/2021] [Accepted: 07/21/2021] [Indexed: 11/12/2022]
Abstract
The ribosome is subjected to post-translational modifications, including phosphorylation, that affect its biological activity. Among ribosomal elements, the P-proteins undergo phosphorylation within the C terminus, the element which interacts with trGTPases or ribosome-inactivating proteins (RIPs); however, the role of phosphorylation has never been elucidated. Here, we probed the function of phosphorylation on the interaction of P-proteins with RIPs using the ribosomal P1-P2 dimer. We determined the kinetic parameters of the interaction with the toxins using biolayer interferometry and microscale thermophoresis. The results present the first mechanistic insight into the function of P-protein phosphorylation, showing that introduction of a negative charge into the C terminus of P1-P2 proteins promotes α-helix formation and decreases the affinity of the P-proteins for the RIPs.
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Affiliation(s)
- Patrycja Horbowicz-Drożdżal
- Department of Molecular Biology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland
| | - Karol Kamel
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
| | - Sebastian Kmiecik
- Biological and Chemical Research Centre, Faculty of Chemistry, University of Warsaw, Poland
| | - Lidia Borkiewicz
- Department of Biochemistry and Molecular Biology, Medical University of Lublin, Poland
| | - Nilgun E Tumer
- Department of Plant Biology and Pathology, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, NJ, USA
| | - Pang-Chui Shaw
- School of Life Sciences, The Chinese University of Hong Kong, China
| | - Marek Tchórzewski
- Department of Molecular Biology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland
| | - Przemysław Grela
- Department of Molecular Biology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland
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5
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Bhat AS, Dustin Schaeffer R, Kinch L, Medvedev KE, Grishin NV. Recent advances suggest increased influence of selective pressure in allostery. Curr Opin Struct Biol 2020; 62:183-188. [PMID: 32302874 DOI: 10.1016/j.sbi.2020.02.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 02/21/2020] [Accepted: 02/25/2020] [Indexed: 12/19/2022]
Abstract
Allosteric regulation of protein functions is ubiquitous in organismal biology, but the principles governing its evolution are not well understood. Here we discuss recent studies supporting the large-scale existence of latent allostery in ancestor proteins of superfamilies. As suggested, the evolution of allostery could be driven by the need for specificity in paralogs of slow evolving protein complexes with conserved active sites. The same slow evolution is displayed by purifying selection exhibited in allosteric proteins with somatic mutations involved in cancer, where disease-associated mutations are enriched in both orthosteric and allosteric sites. Consequently, disease-associated variants can be used to identify druggable allosteric sites that are specific for paralogs in protein superfamilies with otherwise similar functions.
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Affiliation(s)
- Archana S Bhat
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9050, United States
| | - Richard Dustin Schaeffer
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9050, United States
| | - Lisa Kinch
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-9050, United States
| | - Kirill E Medvedev
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9050, United States
| | - Nick V Grishin
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9050, United States; Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-9050, United States.
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6
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Zhao P, Sun X, Chaggan C, Liao Z, In Wong K, He F, Singh S, Loomba R, Karin M, Witztum JL, Saltiel AR. An AMPK-caspase-6 axis controls liver damage in nonalcoholic steatohepatitis. Science 2020; 367:652-660. [PMID: 32029622 PMCID: PMC8012106 DOI: 10.1126/science.aay0542] [Citation(s) in RCA: 178] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 12/23/2019] [Indexed: 12/14/2022]
Abstract
Liver cell death has an essential role in nonalcoholic steatohepatitis (NASH). The activity of the energy sensor adenosine monophosphate (AMP)-activated protein kinase (AMPK) is repressed in NASH. Liver-specific AMPK knockout aggravated liver damage in mouse NASH models. AMPK phosphorylated proapoptotic caspase-6 protein to inhibit its activation, keeping hepatocyte apoptosis in check. Suppression of AMPK activity relieved this inhibition, rendering caspase-6 activated in human and mouse NASH. AMPK activation or caspase-6 inhibition, even after the onset of NASH, improved liver damage and fibrosis. Once phosphorylation was decreased, caspase-6 was activated by caspase-3 or -7. Active caspase-6 cleaved Bid to induce cytochrome c release, generating a feedforward loop that leads to hepatocyte death. Thus, the AMPK-caspase-6 axis regulates liver damage in NASH, implicating AMPK and caspase-6 as therapeutic targets.
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Affiliation(s)
- Peng Zhao
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Xiaoli Sun
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Cynthia Chaggan
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Zhongji Liao
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kai In Wong
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Feng He
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Seema Singh
- NAFLD Research Center, Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Rohit Loomba
- NAFLD Research Center, Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Michael Karin
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Joseph L Witztum
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Alan R Saltiel
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
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7
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Activation of Caspase-6 Is Promoted by a Mutant Huntingtin Fragment and Blocked by an Allosteric Inhibitor Compound. Cell Chem Biol 2019; 26:1295-1305.e6. [PMID: 31353319 DOI: 10.1016/j.chembiol.2019.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 01/08/2019] [Accepted: 06/28/2019] [Indexed: 01/04/2023]
Abstract
Aberrant activation of caspase-6 (C6) in the absence of other hallmarks of apoptosis has been demonstrated in cells and tissues from patients with Huntington disease (HD) and animal models. C6 activity correlates with disease progression in patients with HD and the cleavage of mutant huntingtin (mHTT) protein is thought to strongly contribute to disease pathogenesis. Here we show that the mHTT1-586 fragment generated by C6 cleavage interacts with the zymogen form of the enzyme, stabilizing a conformation that contains an active site and is prone to full activation. This shift toward enhanced activity can be prevented by a small-molecule inhibitor that blocks the interaction between C6 and mHTT1-586. Molecular docking studies suggest that the inhibitor binds an allosteric site in the C6 zymogen. The interaction of mHTT1-586 with C6 may therefore promote a self-reinforcing, feedforward cycle of C6 zymogen activation and mHTT cleavage driving HD pathogenesis.
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8
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Dhuriya YK, Sharma D, Naik AA. Cellular demolition: Proteins as molecular players of programmed cell death. Int J Biol Macromol 2019; 138:492-503. [PMID: 31330212 DOI: 10.1016/j.ijbiomac.2019.07.113] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 06/25/2019] [Accepted: 07/19/2019] [Indexed: 12/11/2022]
Abstract
Apoptosis, a well-characterized and regulated cell death programme in eukaryotes plays a fundamental role in developing or later-life periods to dispose of unwanted cells to maintain typical tissue architecture, homeostasis in a spatiotemporal manner. This silent cellular death occurs without affecting any neighboring cells/tissue and avoids triggering of immunological response. Furthermore, diminished forms of apoptosis result in cancer and autoimmune diseases, whereas unregulated apoptosis may also lead to the development of a myriad of neurodegenerative diseases. Unraveling the mechanistic events in depth will provide new insights into understanding physiological control of apoptosis, pathological consequences of abnormal apoptosis and development of novel therapeutics for diseases. Here we provide a brief overview of molecular players of programmed cell death with discussion on the role of caspases, modifications, ubiquitylation in apoptosis, removal of the apoptotic body and its relevance to diseases.
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Affiliation(s)
- Yogesh Kumar Dhuriya
- Developmental Toxicology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhawan, 31, Mahatma Gandhi Marg, Lucknow 226 001, India
| | - Divakar Sharma
- Department of Biochemistry, National JALMA Institute for Leprosy and Other Mycobacterial Diseases, Tajganj, Agra, India; Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India.
| | - Aijaz A Naik
- Neurology, School of Medicine, University of Virginia, Charlottesville 22908, United States of America
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9
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Tubeleviciute-Aydin A, Beautrait A, Lynham J, Sharma G, Gorelik A, Deny LJ, Soya N, Lukacs GL, Nagar B, Marinier A, LeBlanc AC. Identification of Allosteric Inhibitors against Active Caspase-6. Sci Rep 2019; 9:5504. [PMID: 30940883 PMCID: PMC6445123 DOI: 10.1038/s41598-019-41930-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 03/21/2019] [Indexed: 01/04/2023] Open
Abstract
Caspase-6 is a cysteine protease that plays essential roles in programmed cell death, axonal degeneration, and development. The excess neuronal activity of Caspase-6 is associated with Alzheimer disease neuropathology and age-dependent cognitive impairment. Caspase-6 inhibition is a promising strategy to stop early stage neurodegenerative events, yet finding potent and selective Caspase-6 inhibitors has been a challenging task due to the overlapping structural and functional similarities between caspase family members. Here, we investigated how four rare non-synonymous missense single-nucleotide polymorphisms (SNPs), resulting in amino acid substitutions outside human Caspase-6 active site, affect enzyme structure and catalytic efficiency. Three investigated SNPs were found to align with a putative allosteric pocket with low sequence conservation among human caspases. Virtual screening of 57,700 compounds against the putative Caspase-6 allosteric pocket, followed by in vitro testing of the best virtual hits in recombinant human Caspase-6 activity assays identified novel allosteric Caspase-6 inhibitors with IC50 and Ki values ranging from ~2 to 13 µM. This report may pave the way towards the development and optimisation of novel small molecule allosteric Caspase-6 inhibitors and illustrates that functional characterisation of rare natural variants holds promise for the identification of allosteric sites on other therapeutic targets in drug discovery.
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Affiliation(s)
- Agne Tubeleviciute-Aydin
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Ch. Cote Ste-Catherine, Montreal, Quebec, H3T 1E2, Canada
- Department of Neurology and Neurosurgery, McGill University, 3775 University St., Montreal, Quebec, H3A 2B4, Canada
| | - Alexandre Beautrait
- Institute for Research in Immunology and Cancer, Université de Montréal, 2590, chemin de Polytechnique, Montreal, Quebec, H3T 1J4, Canada
| | - Jeffrey Lynham
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Ch. Cote Ste-Catherine, Montreal, Quebec, H3T 1E2, Canada
- Department of Anatomy and Cell Biology, McGill University, 3640 University St., Montreal, Quebec, H3A 0C7, Canada
| | - Gyanesh Sharma
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Ch. Cote Ste-Catherine, Montreal, Quebec, H3T 1E2, Canada
- Department of Neurology and Neurosurgery, McGill University, 3775 University St., Montreal, Quebec, H3A 2B4, Canada
| | - Alexei Gorelik
- Department of Biochemistry, McGill University, 3649 promenade Sir-William-Osler, Montreal, Quebec, H3G 0B1, Canada
| | - Ludovic J Deny
- Institute for Research in Immunology and Cancer, Université de Montréal, 2590, chemin de Polytechnique, Montreal, Quebec, H3T 1J4, Canada
| | - Naoto Soya
- Department of Physiology and Biochemistry, McGill University, 3655 Promenade Sir-William-Osler, Montréal, Québec, H3G 1Y6, Canada
| | - Gergely L Lukacs
- Department of Physiology and Biochemistry, McGill University, 3655 Promenade Sir-William-Osler, Montréal, Québec, H3G 1Y6, Canada
| | - Bhushan Nagar
- Department of Biochemistry, McGill University, 3649 promenade Sir-William-Osler, Montreal, Quebec, H3G 0B1, Canada
| | - Anne Marinier
- Institute for Research in Immunology and Cancer, Université de Montréal, 2590, chemin de Polytechnique, Montreal, Quebec, H3T 1J4, Canada
| | - Andrea C LeBlanc
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Ch. Cote Ste-Catherine, Montreal, Quebec, H3T 1E2, Canada.
- Department of Neurology and Neurosurgery, McGill University, 3775 University St., Montreal, Quebec, H3A 2B4, Canada.
- Department of Anatomy and Cell Biology, McGill University, 3640 University St., Montreal, Quebec, H3A 0C7, Canada.
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10
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Islam MI, Nagakannan P, Ogungbola O, Djordjevic J, Albensi BC, Eftekharpour E. Thioredoxin system as a gatekeeper in caspase-6 activation and nuclear lamina integrity: Implications for Alzheimer's disease. Free Radic Biol Med 2019; 134:567-580. [PMID: 30769159 DOI: 10.1016/j.freeradbiomed.2019.02.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 01/28/2019] [Accepted: 02/10/2019] [Indexed: 02/01/2023]
Abstract
Recent reports in pathophysiology of neurodegenerative diseases (ND) have linked nuclear lamina degradation/deficits to neuronal cell death. Lamin-B1 damage is specifically involved in this process leading to nuclear envelope invagination and heterochromatin rearrangement. The underlying mechanisms involved in these events are not yet defined. In this study, while examining the effect of Thioredoxin-1(Trx1) inhibition on cell death in a model of oxidative stress, we noted robust nuclear invagination in SH-SY5Y cells. Evaluation of nuclear lamina proteins revealed lamin-B1 cleavage that was prevented by caspase-6 (CASP6) inhibitor and exacerbated after pharmacologic/genetic inhibition of Trx1 system, but not after glutathione depletion. Activation of CASP6 was upstream of CASP3/7 activation and its inhibition was sufficient to prevent cell death in our system. The effect of Trx1 redox status on CASP6 activation was assessed by administration of reduced/oxidized forms in cell-free nuclei preparation and purified enzymatic assays. Although reduced Trx1 decreased CASP6 enzymatic activity and lamin-B1 cleavage, the fully oxidized Trx1 showed opposite effects. The enhanced CASP6 activation was also associated with lower levels of DJ-1, a neuroprotective and master regulator of cellular antioxidants. The implication of our findings in ND pathophysiology was strengthened with detection of lower Trx1 levels in the hippocampi tissue of a mouse model of Alzheimer's disease. This coincided with higher CASP6 activation resulting in increased lamin-B1 and DJ-1 depletion. This study provides a first mechanistic explanation for the key regulatory role of Trx1 as a gatekeeper in activation of CASP6 and induction of nuclear invagination, an important player in ND pathophysiology.
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Affiliation(s)
- Md Imamul Islam
- Regenerative Medicine Program and Spinal Cord Research Centre, Canada; Dept. Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada
| | - Pandian Nagakannan
- Regenerative Medicine Program and Spinal Cord Research Centre, Canada; Dept. Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada
| | - Olamide Ogungbola
- Regenerative Medicine Program and Spinal Cord Research Centre, Canada; Dept. Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada
| | - Jelena Djordjevic
- Division of Neurodegenerative Disorders, St. Boniface Hospital Research, Winnipeg, Manitoba, Canada; Department of Pharmacology and Therapeutics, Faculty of Health Sciences, College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Benedict C Albensi
- Division of Neurodegenerative Disorders, St. Boniface Hospital Research, Winnipeg, Manitoba, Canada; Department of Pharmacology and Therapeutics, Faculty of Health Sciences, College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Eftekhar Eftekharpour
- Regenerative Medicine Program and Spinal Cord Research Centre, Canada; Dept. Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada.
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11
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Abstract
The cysteine protease Caspase-6 (Casp6) is a potential therapeutic target of Alzheimer Disease (AD) and age-dependent cognitive impairment. To assess if Casp6 is essential to human health, we investigated the effect of CASP6 variants sequenced from healthy humans on Casp6 activity. Here, we report the effects of two rare Casp6 amino acid polymorphisms, R65W and G66R, on the catalytic function and structure of Casp6. The G66R substitution eliminated and R65W substitution significantly reduced Casp6 catalytic activity through impaired substrate binding. In contrast to wild-type Casp6, both Casp6 variants were unstable and inactive in transfected mammalian cells. In addition, Casp6-G66R acted as a dominant negative inhibitor of wild-type Casp6. The R65W and G66R substitutions caused perturbations in substrate recognition and active site organization as revealed by molecular dynamics simulations. Our results suggest that full Casp6 activity may not be essential for healthy humans and support the use of Casp6 inhibitors against Casp6-dependent neurodegeneration in age-dependent cognitive impairment and AD. Furthermore, this work illustrates that studying natural single amino acid polymorphisms of enzyme drug targets is a promising approach to uncover previously uncharacterized regulatory sites important for enzyme activity.
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12
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Caspase-8 function, and phosphorylation, in cell migration. Semin Cell Dev Biol 2018; 82:105-117. [PMID: 29410361 DOI: 10.1016/j.semcdb.2018.01.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 01/17/2018] [Accepted: 01/21/2018] [Indexed: 11/22/2022]
Abstract
Caspase-8 is involved in a number of cellular functions, with the most well established being the control of cell death. Yet caspase-8 is unique among the caspases in that it acts as an environmental sensor, transducing a range of signals to cells, modulating responses that extend far beyond simple survival. Ranging from the control of apoptosis and necroptosis and gene regulation to cell adhesion and migration, caspase-8 uses proteolytic and non-proteolytic functions to alter cell behavior. Novel interacting partners provide mechanisms for caspase-8 to position itself at signaling nodes that affect a variety of signaling pathways. Here, we examine the catalytic and noncatalytic modes of action by which caspase-8 influences cell adhesion and migration. The mechanisms vary from post-cleavage remodeling of the cytoskeleton to signaling elements that control focal adhesion turnover. This is facilitated by caspase-8 interaction with a host of cell proteins ranging from the proteases caspase-3 and calpain-2 to adaptor proteins such as p85 and Crk, to the Src family of tyrosine kinases.
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13
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Phosphorylation by protein kinase A disassembles the caspase-9 core. Cell Death Differ 2018; 25:1025-1039. [PMID: 29352269 DOI: 10.1038/s41418-017-0052-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 11/30/2017] [Accepted: 12/05/2017] [Indexed: 01/04/2023] Open
Abstract
Caspases, the cysteine proteases which facilitate the faithful execution of apoptosis, are tightly regulated by a number of mechanisms including phosphorylation. In response to cAMP, PKA phosphorylates caspase-9 at three sites preventing caspase-9 activation, and suppressing apoptosis progression. Phosphorylation of caspase-9 by PKA at the functionally relevant site Ser-183 acts as an upstream block of the apoptotic cascade, directly inactivating caspase-9 by a two-stage mechanism. First, Ser-183 phosphorylation prevents caspase-9 self-processing and directly blocks substrate binding. In addition, Ser-183 phosphorylation breaks the fundamental interactions within the caspase-9 core, promoting disassembly of the large and small subunits. This occurs despite Ser-183 being a surface residue distal from the interface between the large and small subunits. This phosphorylation-induced disassembly promotes the formation of ordered aggregates around 20 nm in diameter. Similar aggregates of caspase-9 have not been previously reported. This two-stage regulatory mechanism for caspase-9 has likewise not been reported previously but may be conserved across the caspases.
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14
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Serrano BP, Szydlo HS, Alfandari D, Hardy JA. Active site-adjacent phosphorylation at Tyr-397 by c-Abl kinase inactivates caspase-9. J Biol Chem 2017; 292:21352-21365. [PMID: 29066624 DOI: 10.1074/jbc.m117.811976] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 10/11/2017] [Indexed: 12/11/2022] Open
Abstract
Caspase-9 (casp-9) is an initiator caspase and plays a central role in activating apoptotic cell death. Control of all caspases is tightly regulated by a series of phosphorylation events enacted by several different kinases. Caspase-9 is the most heavily phosphorylated of all caspases, with phosphorylation of at least 11 distinct residues in all three caspase-9 domains by nine kinases. Caspase-9 phosphorylation by the non-receptor tyrosine kinase c-Abl at Tyr-153 reportedly leads to caspase-9 activation. All other phosphorylation events on caspases have been shown to block proteolytic function by a number of mechanisms, so we sought to unravel the molecular mechanism of the putative caspase-9 activation by phosphorylation. Surprisingly, we observed no evidence for Tyr-153 phosphorylation of caspase-9 in vitro or in cells, suggesting that Tyr-153 is not phosphorylated by c-Abl. Instead, we identified a new site for c-Abl-mediated phosphorylation, Tyr-397. This residue is adjacent to the caspase-9 active site but, as a member of the second shell, not a residue that directly contacts substrate. Our results further indicate that Tyr-397 is the dominant site of c-Abl phosphorylation both in vitro and upon c-Abl activation in cells. Of note, phosphorylation at this site inhibits caspase-9 activity, and the bulk of the added phosphate moiety appeared to directly block substrate binding. c-Abl plays both proapoptotic and prosurvival roles, and our findings suggest that c-Abl's effects on caspase-9 activity promote the prosurvival mode.
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Affiliation(s)
| | - Hannah S Szydlo
- Veterinary and Animal Sciences, University of Massachusetts, Amherst, Massachusetts 01003
| | - Dominique Alfandari
- Veterinary and Animal Sciences, University of Massachusetts, Amherst, Massachusetts 01003
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15
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Dagbay KB, Hill ME, Barrett E, Hardy JA. Tumor-Associated Mutations in Caspase-6 Negatively Impact Catalytic Efficiency. Biochemistry 2017; 56:4568-4577. [PMID: 28726391 DOI: 10.1021/acs.biochem.7b00357] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Unregulated, particularly suppressed programmed cell death is one of the distinguishing features of many cancer cells. The cysteine protease caspase-6, one of the executioners of apoptotic cell death, plays a crucial role in regulation of apoptosis. Several somatic mutations in the CASP6 gene in tumor tissues have been reported. This work explores the effect of CASP6 tumor-associated mutations on the catalytic efficiency and structure of caspase-6. In general, these mutations showed decreased overall rates of catalytic turnover. Mutations within 8 Å of the substrate-binding pocket of caspase-6 were found to be the most catalytically deactivating. Notably, the R259H substitution decreased activity by 457-fold. This substitution disrupts the cation-π stacking interaction between Arg-259 and Trp-227, which is indispensable for proper assembly of the substrate-binding loops in caspase-6. Sequence conservation analysis at the homologous position across the caspase family suggests a role for this cation-π stacking in the catalytic function of caspases generally. These data suggest that caspase-6 deactivating mutations may contribute to multifactorial carcinogenic transformations.
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Affiliation(s)
- Kevin B Dagbay
- Department of Chemistry, University of Massachusetts Amherst , Amherst, Massachusetts 01003, United States
| | - Maureen E Hill
- Department of Chemistry, University of Massachusetts Amherst , Amherst, Massachusetts 01003, United States
| | - Elizabeth Barrett
- Department of Chemistry, University of Massachusetts Amherst , Amherst, Massachusetts 01003, United States
| | - Jeanne A Hardy
- Department of Chemistry, University of Massachusetts Amherst , Amherst, Massachusetts 01003, United States
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16
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Alves J, Garay-Malpartida M, Occhiucci JM, Belizário JE. Modulation of procaspase-7 self-activation by PEST amino acid residues of the N-terminal prodomain and intersubunit linker. Biochem Cell Biol 2017; 95:634-643. [PMID: 28658581 DOI: 10.1139/bcb-2016-0220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Procaspase-7 zymogen polypeptide is composed of a short prodomain, a large subunit (p20), and a small subunit (p10) connected to an intersubunit linker. Caspase-7 is activated by an initiator caspase-8 and -9, or by autocatalysis after specific cleavage at IQAD198↓S located at the intersubunit linker. Previously, we identified that PEST regions made of amino acid residues Pro (P), Glu (E), Asp (D), Ser (S), Thr (T), Asn (N), and Gln (Q) are conserved flanking amino acid residues in the cleavage sites within a prodomain and intersubunit linker of all caspase family members. Here we tested the impact of alanine substitution of PEST amino acid residues on procaspase-7 proteolytic self-activation directly in Escherichia coli. The p20 and p10 subunit cleavage were significantly delayed in double caspase-7 mutants in the prodomain (N18A/P26A) and intersubunit linker (S199A/P201A), compared with the wild-type caspase-7. The S199A/P201A mutants effectively inhibited the p10 small subunit cleavage. However, the mutations did not change the kinetic parameters (kcat/KM) and optimal tetrapeptide specificity (DEVD) of the purified mutant enzymes. The results suggest a role of PEST-amino acid residues in the molecular mechanism for prodomain and intersubunit cleavage and caspase-7 self-activation.
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Affiliation(s)
- Juliano Alves
- a Department of Pharmacology, Institute of Biomedical Sciences, Avenida Lineu Prestes, 1524, São Paulo, SP, 05508-900, Brazil
| | - Miguel Garay-Malpartida
- b School of Arts, Communication and Humanity, University of São Paulo, Rua Arlindo Béttio, 1000, São Paulo, SP, 03828-000, Brazil
| | - João M Occhiucci
- a Department of Pharmacology, Institute of Biomedical Sciences, Avenida Lineu Prestes, 1524, São Paulo, SP, 05508-900, Brazil
| | - José E Belizário
- a Department of Pharmacology, Institute of Biomedical Sciences, Avenida Lineu Prestes, 1524, São Paulo, SP, 05508-900, Brazil
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17
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Skotte NH, Sanders SS, Singaraja RR, Ehrnhoefer DE, Vaid K, Qiu X, Kannan S, Verma C, Hayden MR. Palmitoylation of caspase-6 by HIP14 regulates its activation. Cell Death Differ 2017; 24:433-444. [PMID: 27911442 PMCID: PMC5344205 DOI: 10.1038/cdd.2016.139] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 10/03/2016] [Accepted: 10/25/2016] [Indexed: 02/06/2023] Open
Abstract
Caspase-6 (CASP6) has an important role in axonal degeneration during neuronal apoptosis and in the neurodegenerative diseases Alzheimer and Huntington disease. Decreasing CASP6 activity may help to restore neuronal function in these and other diseases such as stroke and ischemia, where increased CASP6 activity has been implicated. The key to finding approaches to decrease CASP6 activity is a deeper understanding of the mechanisms regulating CASP6 activation. We show that CASP6 is posttranslationally palmitoylated by the palmitoyl acyltransferase HIP14 and that the palmitoylation of CASP6 inhibits its activation. Palmitoylation of CASP6 is decreased both in Hip14-/- mice, where HIP14 is absent, and in YAC128 mice, a model of Huntington disease, where HIP14 is dysfunctional and where CASP6 activity is increased. Molecular modeling suggests that palmitoylation of CASP6 may inhibit its activation via steric blockage of the substrate-binding groove and inhibition of CASP6 dimerization, both essential for CASP6 function. Our studies identify palmitoylation as a novel CASP6 modification and as a key regulator of CASP6 activity.
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Affiliation(s)
- Niels H Skotte
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Shaun S Sanders
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Roshni R Singaraja
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
- Translational Laboratories in Genetic Medicine, Agency for Science, Technology and Research, Singapore, Singapore
- Department of Medicine at Yong Loo Lin School of Medicine, National University of Singapore, Singapore 138648, Singapore
| | - Dagmar E Ehrnhoefer
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Kuljeet Vaid
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Xiaofan Qiu
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Srinivasaragavan Kannan
- Bioinformatics Institute, Agency for Science, Technology and Research, 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore
| | - Chandra Verma
- Bioinformatics Institute, Agency for Science, Technology and Research, 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
- School of Biological Sciences, Nanyang Technological University, 50 Nanyang Drive, Singapore 637551, Singapore
| | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
- Translational Laboratories in Genetic Medicine, Agency for Science, Technology and Research, Singapore, Singapore
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18
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Zamaraev AV, Kopeina GS, Prokhorova EA, Zhivotovsky B, Lavrik IN. Post-translational Modification of Caspases: The Other Side of Apoptosis Regulation. Trends Cell Biol 2017; 27:322-339. [PMID: 28188028 DOI: 10.1016/j.tcb.2017.01.003] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 12/21/2016] [Accepted: 01/05/2017] [Indexed: 12/20/2022]
Abstract
Apoptosis is a crucial program of cell death that controls development and homeostasis of multicellular organisms. The main initiators and executors of this process are the Cysteine-dependent ASPartate proteASES - caspases. A number of regulatory circuits tightly control caspase processing and activity. One of the most important, yet, at the same time still poorly understood control mechanisms of activation of caspases involves their post-translational modifications. The addition and/or removal of chemical groups drastically alters the catalytic activity of caspases or stimulates their nonapoptotic functions. In this review, we will describe and discuss the roles of key caspase modifications such as phosphorylation, ubiquitination, nitrosylation, glutathionylation, SUMOylation, and acetylation in the regulation of apoptotic cell death and cell survival.
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Affiliation(s)
- Alexey V Zamaraev
- Faculty of Basic Medicine, MV Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Gelina S Kopeina
- Faculty of Basic Medicine, MV Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Evgeniia A Prokhorova
- Faculty of Basic Medicine, MV Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Boris Zhivotovsky
- Faculty of Basic Medicine, MV Lomonosov Moscow State University, 119991 Moscow, Russia; Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, 17177 Stockholm, Sweden.
| | - Inna N Lavrik
- Faculty of Basic Medicine, MV Lomonosov Moscow State University, 119991 Moscow, Russia; Department of Translational Inflammation, Institute of Experimental Internal Medicine, Otto von Guericke University, Magdeburg, Germany.
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19
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Eron SJ, Raghupathi K, Hardy JA. Dual Site Phosphorylation of Caspase-7 by PAK2 Blocks Apoptotic Activity by Two Distinct Mechanisms. Structure 2016; 25:27-39. [PMID: 27889207 DOI: 10.1016/j.str.2016.11.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/20/2016] [Accepted: 10/27/2016] [Indexed: 01/23/2023]
Abstract
Caspases, the cysteine proteases that execute apoptosis, are tightly regulated via phosphorylation by a series of kinases. Although all apoptotic caspases work in concert to promote apoptosis, different kinases regulate individual caspases. Several sites of caspase-7 phosphorylation have been reported, but without knowing the molecular details, it has been impossible to exploit or control these complex interactions, which normally prevent unwanted proliferation. During dysregulation, PAK2 kinase plays an alternative anti-apoptotic role, phosphorylating caspase-7 and promoting unfettered cell growth and chemotherapeutic resistance. PAK2 phosphorylates caspase-7 at two sites, inhibiting activity using two different molecular mechanisms, before and during apoptosis. Phosphorylation of caspase-7 S30 allosterically obstructs its interaction with caspase-9, preventing intersubunit linker processing, slowing or preventing caspase-7 activation. S239 phosphorylation renders active caspase-7 incapable of binding substrate, blocking later events in apoptosis. Each of these mechanisms is novel, representing new opportunities for synergistic control of caspases and their counterpart kinases.
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Affiliation(s)
- Scott J Eron
- Department of Chemistry, University of Massachusetts Amherst, 104 LGRT, 710 North Pleasant Street, Amherst, MA 01003, USA
| | - Kishore Raghupathi
- Department of Chemistry, University of Massachusetts Amherst, 104 LGRT, 710 North Pleasant Street, Amherst, MA 01003, USA
| | - Jeanne A Hardy
- Department of Chemistry, University of Massachusetts Amherst, 104 LGRT, 710 North Pleasant Street, Amherst, MA 01003, USA.
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20
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Tunable allosteric library of caspase-3 identifies coupling between conserved water molecules and conformational selection. Proc Natl Acad Sci U S A 2016; 113:E6080-E6088. [PMID: 27681633 DOI: 10.1073/pnas.1603549113] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The native ensemble of caspases is described globally by a complex energy landscape where the binding of substrate selects for the active conformation, whereas targeting an allosteric site in the dimer interface selects an inactive conformation that contains disordered active-site loops. Mutations and posttranslational modifications stabilize high-energy inactive conformations, with mostly formed, but distorted, active sites. To examine the interconversion of active and inactive states in the ensemble, we used detection of related solvent positions to analyze 4,995 waters in 15 high-resolution (<2.0 Å) structures of wild-type caspase-3, resulting in 450 clusters with the most highly conserved set containing 145 water molecules. The data show that regions of the protein that contact the conserved waters also correspond to sites of posttranslational modifications, suggesting that the conserved waters are an integral part of allosteric mechanisms. To test this hypothesis, we created a library of 19 caspase-3 variants through saturation mutagenesis in a single position of the allosteric site of the dimer interface, and we show that the enzyme activity varies by more than four orders of magnitude. Altogether, our database consists of 37 high-resolution structures of caspase-3 variants, and we demonstrate that the decrease in activity correlates with a loss of conserved water molecules. The data show that the activity of caspase-3 can be fine-tuned through globally desolvating the active conformation within the native ensemble, providing a mechanism for cells to repartition the ensemble and thus fine-tune activity through conformational selection.
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21
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Hill ME, MacPherson DJ, Wu P, Julien O, Wells JA, Hardy JA. Reprogramming Caspase-7 Specificity by Regio-Specific Mutations and Selection Provides Alternate Solutions for Substrate Recognition. ACS Chem Biol 2016; 11:1603-12. [PMID: 27032039 DOI: 10.1021/acschembio.5b00971] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The ability to routinely engineer protease specificity can allow us to better understand and modulate their biology for expanded therapeutic and industrial applications. Here, we report a new approach based on a caged green fluorescent protein (CA-GFP) reporter that allows for flow-cytometry-based selection in bacteria or other cell types enabling selection of intracellular protease specificity, regardless of the compositional complexity of the protease. Here, we apply this approach to introduce the specificity of caspase-6 into caspase-7, an intracellular cysteine protease important in cellular remodeling and cell death. We found that substitution of substrate-contacting residues from caspase-6 into caspase-7 was ineffective, yielding an inactive enzyme, whereas saturation mutagenesis at these positions and selection by directed evolution produced active caspases. The process produced a number of nonobvious mutations that enabled conversion of the caspase-7 specificity to match caspase-6. The structures of the evolved-specificity caspase-7 (esCasp-7) revealed alternate binding modes for the substrate, including reorganization of an active site loop. Profiling the entire human proteome of esCasp-7 by N-terminomics demonstrated that the global specificity toward natural protein substrates is remarkably similar to that of caspase-6. Because the esCasp-7 maintained the core of caspase-7, we were able to identify a caspase-6 substrate, lamin C, that we predict relies on an exosite for substrate recognition. These reprogrammed proteases may be the first tool built with the express intent of distinguishing exosite dependent or independent substrates. This approach to specificity reprogramming should also be generalizable across a wide range of proteases.
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Affiliation(s)
- Maureen E. Hill
- Department
of Chemistry, 104 LGRT,
710 N. Pleasant St., University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Derek J. MacPherson
- Department
of Chemistry, 104 LGRT,
710 N. Pleasant St., University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Peng Wu
- Department
of Chemistry, 104 LGRT,
710 N. Pleasant St., University of Massachusetts, Amherst, Massachusetts 01003, United States
| | | | | | - Jeanne A. Hardy
- Department
of Chemistry, 104 LGRT,
710 N. Pleasant St., University of Massachusetts, Amherst, Massachusetts 01003, United States
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22
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Unsain N, Barker PA. New Views on the Misconstrued: Executioner Caspases and Their Diverse Non-apoptotic Roles. Neuron 2016; 88:461-74. [PMID: 26539888 DOI: 10.1016/j.neuron.2015.08.029] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Initially characterized for their roles in apoptosis, executioner caspases have emerged as important regulators of an array of cellular activities. This is especially true in the nervous system, where sublethal caspase activity has been implicated in axonal pathfinding and branching, axonal degeneration, dendrite pruning, regeneration, long-term depression, and metaplasticity. Here we examine the roles of sublethal executioner caspase activity in nervous system development and maintenance, consider the mechanisms that locally activate and restrain these potential killers, and discuss how their activity be subverted in neurodegenerative disease.
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Affiliation(s)
- Nicolas Unsain
- Laboratorio de Neurobiología, Instituto de Investigación Médica Mercedes y Martín Ferreyra, Instituto Nacional de Investigación Médica Córdoba-Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Córdoba, Friuli 2434, Córdoba (5016), Argentina
| | - Philip A Barker
- Irving K. Barber School of Arts and Sciences, University of British Columbia, Kelowna, BC V1V 1V7, Canada.
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23
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Abstract
The role of caspase proteases in regulated processes such as apoptosis and inflammation has been studied for more than two decades, and the activation cascades are known in detail. Apoptotic caspases also are utilized in critical developmental processes, although it is not known how cells maintain the exquisite control over caspase activity in order to retain subthreshold levels required for a particular adaptive response while preventing entry into apoptosis. In addition to active site-directed inhibitors, caspase activity is modulated by post-translational modifications or metal binding to allosteric sites on the enzyme, which stabilize inactive states in the conformational ensemble. This review provides a comprehensive global view of the complex conformational landscape of caspases and mechanisms used to select states in the ensemble. The caspase structural database provides considerable detail on the active and inactive conformations in the ensemble, which provide the cell multiple opportunities to fine tune caspase activity. In contrast, the current database on caspase modifications is largely incomplete and thus provides only a low-resolution picture of global allosteric communications and their effects on the conformational landscape. In recent years, allosteric control has been utilized in the design of small drug compounds or other allosteric effectors to modulate caspase activity.
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Affiliation(s)
- A Clay Clark
- Department of Biology, University of Texas at Arlington , Arlington, Texas 76019, United States
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24
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Pakavathkumar P, Sharma G, Kaushal V, Foveau B, LeBlanc AC. Methylene Blue Inhibits Caspases by Oxidation of the Catalytic Cysteine. Sci Rep 2015; 5:13730. [PMID: 26400108 PMCID: PMC4585840 DOI: 10.1038/srep13730] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 08/03/2015] [Indexed: 12/20/2022] Open
Abstract
Methylene blue, currently in phase 3 clinical trials against Alzheimer Disease, disaggregates the Tau protein of neurofibrillary tangles by oxidizing specific cysteine residues. Here, we investigated if methylene blue can inhibit caspases via the oxidation of their active site cysteine. Methylene blue, and derivatives, azure A and azure B competitively inhibited recombinant Caspase-6 (Casp6), and inhibited Casp6 activity in transfected human colon carcinoma cells and in serum-deprived primary human neuron cultures. Methylene blue also inhibited recombinant Casp1 and Casp3. Furthermore, methylene blue inhibited Casp3 activity in an acute mouse model of liver toxicity. Mass spectrometry confirmed methylene blue and azure B oxidation of the catalytic Cys163 cysteine of Casp6. Together, these results show a novel inhibitory mechanism of caspases via sulfenation of the active site cysteine. These results indicate that methylene blue or its derivatives could (1) have an additional effect against Alzheimer Disease by inhibiting brain caspase activity, (2) be used as a drug to prevent caspase activation in other conditions, and (3) predispose chronically treated individuals to cancer via the inhibition of caspases.
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Affiliation(s)
- Prateep Pakavathkumar
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Gyanesh Sharma
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Vikas Kaushal
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Bénédicte Foveau
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Andrea C. LeBlanc
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
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25
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Cade C, Swartz P, MacKenzie SH, Clark AC. Modifying caspase-3 activity by altering allosteric networks. Biochemistry 2014; 53:7582-95. [PMID: 25343534 PMCID: PMC4263430 DOI: 10.1021/bi500874k] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Caspases have several allosteric sites that bind small molecules or peptides. Allosteric regulators are known to affect caspase enzyme activity, in general, by facilitating large conformational changes that convert the active enzyme to a zymogen-like form in which the substrate-binding pocket is disordered. Mutations in presumed allosteric networks also decrease activity, although large structural changes are not observed. Mutation of the central V266 to histidine in the dimer interface of caspase-3 inactivates the enzyme by introducing steric clashes that may ultimately affect positioning of a helix on the protein surface. The helix is thought to connect several residues in the active site to the allosteric dimer interface. In contrast to the effects of small molecule allosteric regulators, the substrate-binding pocket is intact in the mutant, yet the enzyme is inactive. We have examined the putative allosteric network, in particular the role of helix 3, by mutating several residues in the network. We relieved steric clashes in the context of caspase-3(V266H), and we show that activity is restored, particularly when the restorative mutation is close to H266. We also mimicked the V266H mutant by introducing steric clashes elsewhere in the allosteric network, generating several mutants with reduced activity. Overall, the data show that the caspase-3 native ensemble includes the canonical active state as well as an inactive conformation characterized by an intact substrate-binding pocket, but with an altered helix 3. The enzyme activity reflects the relative population of each species in the native ensemble.
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Affiliation(s)
- Christine Cade
- Department of Molecular and Structural Biochemistry and ‡Center for Comparative Medicine and Translational Research, North Carolina State University , Raleigh, North Carolina 27695, United States
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26
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Wang XJ, Cao Q, Zhang Y, Su XD. Activation and regulation of caspase-6 and its role in neurodegenerative diseases. Annu Rev Pharmacol Toxicol 2014; 55:553-72. [PMID: 25340928 DOI: 10.1146/annurev-pharmtox-010814-124414] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Caspases, a family of cysteine proteases, are major mediators of apoptosis and inflammation. Caspase-6 is classified as an apoptotic effector, and it mediates nuclear shrinkage during apoptosis, but it possesses unique activation and regulation mechanisms that differ from those of other effector caspases. Furthermore, increasing evidence has shown that caspase-6 is highly involved in axon degeneration and neurodegenerative diseases, such as Huntington's disease and Alzheimer's disease. Cleavage at the caspase-6 site in mutated huntingtin protein is a prerequisite for the development of the characteristic behavioral and neuropathological features of Huntington's disease. Active caspase-6 is present in early stages of Alzheimer's disease, and caspase-6 activity is associated with the disease's pathological lesions. In this review, we discuss the evidence relevant to the role of caspase-6 in neurodegenerative diseases and summarize its activation and regulation mechanisms. In doing so, we provide new insight about potential therapeutic approaches that incorporate the modulation of caspase-6 function for the treatment of neurodegenerative diseases.
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Affiliation(s)
- Xiao-Jun Wang
- State Key Laboratory of Protein and Plant Gene Research and
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27
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Dagbay K, Eron SJ, Serrano BP, Velázquez-Delgado EM, Zhao Y, Lin D, Vaidya S, Hardy JA. A multipronged approach for compiling a global map of allosteric regulation in the apoptotic caspases. Methods Enzymol 2014; 544:215-49. [PMID: 24974292 DOI: 10.1016/b978-0-12-417158-9.00009-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
One of the most promising and as yet underutilized means of regulating protein function is exploitation of allosteric sites. All caspases catalyze the same overall reaction, but they perform different biological roles and are differentially regulated. It is our hypothesis that many allosteric sites exist on various caspases and that understanding both the distinct and overlapping mechanisms by which each caspase can be allosterically controlled should ultimately enable caspase-specific inhibition. Here we describe the ongoing work and methods for compiling a comprehensive map of apoptotic caspase allostery. Central to this approach are the use of (i) the embedded record of naturally evolved allosteric sites that are sensitive to zinc-mediated inhibition, phosphorylation, and other posttranslational modifications, (ii) structural and mutagenic approaches, and (iii) novel binding sites identified by both rationally-designed and screening-derived small-molecule inhibitors.
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Affiliation(s)
- Kevin Dagbay
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts, USA
| | - Scott J Eron
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts, USA
| | - Banyuhay P Serrano
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts, USA
| | | | - Yunlong Zhao
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts, USA
| | - Di Lin
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts, USA
| | - Sravanti Vaidya
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts, USA
| | - Jeanne A Hardy
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts, USA.
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Cao Q, Wang XJ, Li LF, Su XD. The regulatory mechanism of the caspase 6 pro-domain revealed by crystal structure and biochemical assays. ACTA ACUST UNITED AC 2013; 70:58-67. [PMID: 24419379 DOI: 10.1107/s1399004713024218] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 08/29/2013] [Indexed: 11/10/2022]
Abstract
Caspase 6 (CASP6) is a neuron degeneration-related protease and is widely considered to be a potential drug-design target against neurodegenerative diseases such as Huntington's disease and Alzheimer's disease. The N-terminal pro-peptide of CASP6, also referred to as the pro-domain, contains 23 residues and its functional role remains elusive. In this study, the crystal structure of a full-length CASP6 zymogen mutant, proCASP6H121A, was solved. Although the pro-domain was flexible in the crystal, without visible electron density, structural analyses combined with biochemical assays revealed that the pro-domain inhibited CASP6 auto-activation by inhibiting intramolecular cleavage at the intersubunit cleavage site TEVD(193) and also by preventing this site from intermolecular cleavage at low protein concentration through a so-called `suicide-protection' mechanism. Further experiments showed that the length of the pro-domain and the side chain of Asn18 played critical roles in suicide protection. These results disclosed a new inhibitory mechanism of CASP6 and shed light on the pathogenesis and therapeutically relevant study of CASP6-related neurodegenerative diseases.
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Affiliation(s)
- Qin Cao
- State Key Laboratory of Protein and Plant Gene Research, and Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Xiao-Jun Wang
- State Key Laboratory of Protein and Plant Gene Research, and Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Lan-Fen Li
- State Key Laboratory of Protein and Plant Gene Research, and Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Xiao-Dong Su
- State Key Laboratory of Protein and Plant Gene Research, and Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, People's Republic of China
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LeBlanc AC. Caspase-6 as a novel early target in the treatment of Alzheimer's disease. Eur J Neurosci 2013; 37:2005-18. [DOI: 10.1111/ejn.12250] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 04/01/2013] [Accepted: 04/06/2013] [Indexed: 12/16/2022]
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Structural snapshots reveal distinct mechanisms of procaspase-3 and -7 activation. Proc Natl Acad Sci U S A 2013; 110:8477-82. [PMID: 23650375 DOI: 10.1073/pnas.1306759110] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Procaspase-3 (P3) and procaspase-7 (P7) are activated through proteolytic maturation to form caspase-3 (C3) and caspase-7 (C7), respectively, which serve overlapping but nonredundant roles as the executioners of apoptosis in humans. However, it is unclear if differences in P3 and P7 maturation mechanisms underlie their unique biological functions, as the structure of P3 remains unknown. Here, we report structures of P3 in a catalytically inactive conformation, structures of P3 and P7 bound to covalent peptide inhibitors that reveal the active conformation of the zymogens, and the structure of a partially matured C7:P7 heterodimer. Along with a biochemical analysis, we show that P3 is catalytically inactive and matures through a symmetric all-or-nothing process. In contrast, P7 contains latent catalytic activity and matures through an asymmetric and tiered mechanism, suggesting a lower threshold for activation. Finally, we use our structures to design a selection strategy for conformation specific antibody fragments that stimulate procaspase activity, showing that executioner procaspase conformational equilibrium can be rationally modulated. Our studies provide a structural framework that may help to explain the unique roles of these important proapoptotic enzymes, and suggest general strategies for the discovery of proenzyme activators.
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31
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Apicularen A acetate induces cell death via AIF translocation and disrupts the microtubule network by down-regulating tubulin in HM7 human colon cancer cells. Biochem Biophys Res Commun 2013; 434:634-40. [DOI: 10.1016/j.bbrc.2013.03.133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 03/29/2013] [Indexed: 11/18/2022]
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Velázquez-Delgado EM, Hardy JA. Zinc-mediated allosteric inhibition of caspase-6. J Biol Chem 2012; 287:36000-11. [PMID: 22891250 DOI: 10.1074/jbc.m112.397752] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Zinc and caspase-6 have independently been implicated in several neurodegenerative disorders. Depletion of zinc intracellularly leads to apoptosis by an unknown mechanism. Zinc inhibits cysteine proteases, including the apoptotic caspases, leading to the hypothesis that zinc-mediated inhibition of caspase-6 might contribute to its regulation in a neurodegenerative context. Using inductively coupled plasma optical emission spectroscopy, we observed that caspase-6 binds one zinc per monomer, under the same conditions where the zinc leads to complete loss of enzymatic activity. To understand the molecular details of zinc binding and inhibition, we performed an anomalous diffraction experiment above the zinc edge. The anomalous difference maps showed strong 5σ peaks, indicating the presence of one zinc/monomer bound at an exosite distal from the active site. Zinc was not observed bound to the active site. The zinc in the exosite was liganded by Lys-36, Glu-244, and His-287 with a water molecule serving as the fourth ligand, forming a distorted tetrahedral ligation sphere. This exosite appears to be unique to caspase-6, as the residues involved in zinc binding were not conserved across the caspase family. Our data suggest that binding of zinc at the exosite is the primary route of inhibition, potentially locking caspase-6 into the inactive helical conformation.
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Kominami K, Nakabayashi J, Nagai T, Tsujimura Y, Chiba K, Kimura H, Miyawaki A, Sawasaki T, Yokota H, Manabe N, Sakamaki K. The molecular mechanism of apoptosis upon caspase-8 activation: quantitative experimental validation of a mathematical model. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:1825-40. [PMID: 22801217 DOI: 10.1016/j.bbamcr.2012.07.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 06/29/2012] [Accepted: 07/06/2012] [Indexed: 12/22/2022]
Abstract
Caspase-8 (CASP8) is a cysteine protease that plays a pivotal role in the extrinsic apoptotic signaling pathway via death receptors. The kinetics, dynamics, and selectivity with which the pathway transmits apoptotic signals to downstream molecules upon CASP8 activation are not fully understood. We have developed a system for using high-sensitivity FRET-based biosensors to monitor the protease activity of CASP8 and its downstream effector, caspase-3, in living single cells. Using this system, we systematically investigated the caspase cascade by regulating the magnitude of extrinsic signals received by the cell. Furthermore, we determined the molar concentration of five caspases and Bid required for hierarchical transmission of apoptotic signals in a HeLa cell. Based on these quantitative experimental data, we validated a mathematical model suitable for estimation of the kinetics and dynamics of caspases, which predicts the minimal concentration of CASP8 required to act as an initiator. Consequently, we found that less than 1% of the total CASP8 proteins are sufficient to set the apoptotic program in motion if activated. Taken together, our findings demonstrate the precise cascade of CASP8-mediated apoptotic signals through the extrinsic pathway.
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Affiliation(s)
- Katsuya Kominami
- Department of Animal Development and Physiology, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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Abstract
Phosphorylation is a reversible post-translational modification that regulates many proteins and enzymes, including proteases, as shown by two recent publications. Huang and colleagues and Velázquez-Delgado and Hardy (this issue of Structure) describe how phosphorylation activates the protease activity of the deubiquitinating enzyme DUBA and how it inhibits caspase-6, respectively.
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Affiliation(s)
- Martin Renatus
- Novartis Institutes for BioMedical Research, Forum 1, Novartis Campus, CH-4002 Basel, Switzerland.
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