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Selim MS, Mounier MM, Abdelhamid SA, Hamed AA, Abo Elsoud MM, Mohamed SS. Characterization, modeling, and anticancer activity of L.arginase production from marine Bacillus licheniformis OF2. BMC Biotechnol 2024; 24:6. [PMID: 38273334 PMCID: PMC10811824 DOI: 10.1186/s12896-024-00829-6] [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: 11/12/2023] [Accepted: 01/03/2024] [Indexed: 01/27/2024] Open
Abstract
BACKGROUND L-arginase, is a powerful anticancer that hydrolyzes L-arginine to L-ornithine and urea. This enzyme is widely distributed and expressed in organisms like plants, fungi, however very scarce from bacteria. Our study is based on isolating, purifying, and screening the marine bacteria that can produce arginase. RESULTS The highest arginase producing bacteria will be identified by using microbiological and molecular biology methods as Bacillus licheniformis OF2. Characterization of arginase is the objective of this study. The activity of enzyme was screened, and estimated beside partial sequencing of arginase gene was analyzed. In silico homology modeling was applied to generate the protein's 3D structure, and COACH and COFACTOR were applied to determine the protein's binding sites and biological annotations based on the I-TASSER structure prediction. The purified enzyme was undergone an in vitro anticancer test. CONCLUSIONS L-arginase demonstrated more strong anti-cancer cells with an IC50 of 21.4 ug/ml in a dose-dependent manner. L-arginase underwent another investigation for its impact on the caspase 7 and BCL2 family of proteins (BCL2, Bax, and Bax/Bcl2). Through cell arrest in the G1/S phase, L-arginase signals the apoptotic cascade, which is supported by a flow cytometry analysis of cell cycle phases.
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Affiliation(s)
- Manal S Selim
- Microbial Biotechnology Department, National Research Centre, Cairo, Egypt
| | - Marwa M Mounier
- Pharmacognosy Department, National Research Centre, Cairo, Egypt
| | | | | | | | - Sahar S Mohamed
- Microbial Biotechnology Department, National Research Centre, Cairo, Egypt
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2
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Wei S, Feng M, Zhang S. Molecular Characteristics of Cell Pyroptosis and Its Inhibitors: A Review of Activation, Regulation, and Inhibitors. Int J Mol Sci 2022; 23:ijms232416115. [PMID: 36555757 PMCID: PMC9783510 DOI: 10.3390/ijms232416115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 12/02/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Pyroptosis is an active and ordered form of programmed cell death. The signaling pathways of pyroptosis are mainly divided into canonical pathways mediated by caspase-1 and noncanonical pathways mediated by caspase-11. Cell pyroptosis is characterized by the activation of inflammatory caspases (mainly caspase-1, 4, 5, 11) and cleavage of various members of the Gasdermin family to form membrane perforation components, leading to cell membrane rupture, inflammatory mediators release, and cell death. Moderate pyroptosis is an innate immune response that fights against infection and plays an important role in the occurrence and development of the normal function of the immune system. However, excessive pyroptosis occurs and leads to immune disorders in many pathological conditions. Based on canonical pathways, research on pyroptosis regulation has demonstrated several pyroptotic inhibitors, including small-molecule drugs, natural products, and formulations of traditional Chinese medicines. In this paper, we review the characteristics and molecular mechanisms of pyroptosis, summarize inhibitors of pyroptosis, and propound that herbal medicines should be a focus on the research and development for pyroptosis blockers.
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Affiliation(s)
| | | | - Shidong Zhang
- Correspondence: ; Tel.: +86-931-211-5256; Fax: +86-931-211-5191
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3
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New 1,2,3-Triazole-Coumarin-Glycoside Hybrids and Their 1,2,4-Triazolyl Thioglycoside Analogs Targeting Mitochondria Apoptotic Pathway: Synthesis, Anticancer Activity and Docking Simulation. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27175688. [PMID: 36080455 PMCID: PMC9458111 DOI: 10.3390/molecules27175688] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/27/2022] [Accepted: 08/30/2022] [Indexed: 12/02/2022]
Abstract
Toxicity and resistance to newly synthesized anticancer drugs represent a challenging phenomenon of intensified concern arising from variation in drug targets and consequently the prevalence of the latter concern requires further research. The current research reports the design, synthesis, and anticancer activity of new 1,2,3-triazole-coumarin-glycosyl hybrids and their 1,2,4-triazole thioglycosides as well as acyclic analogs. The cytotoxic activity of the synthesized products was studied against a panel of human cancer cell lines. Compounds 8, 10, 16 and 21 resulted in higher activities against different human cancer cells. The impact of the hybrid derivative 10 upon different apoptotic protein markers, including cytochrome c, Bcl-2, Bax, and caspase-7 along with its effect on the cell cycle was investigated. It revealed a mitochondria-apoptotic effect on MCF-7 cells and had the ability to upregulate pro-apoptotic Bax protein and downregulate anti-apoptotic Bcl-2 protein and thus implies the apoptotic fate of the cells. Furthermore, the inhibitory activities against EGFR, VEGFR-2 and CDK-2/cyclin A2 kinases for 8, 10 and 21 were studied to detect the mechanism of their high potency. The coumarin-triazole-glycosyl hybrids 8 and 10 illustrated excellent broad inhibitory activity (IC50= 0.22 ± 0.01, 0.93 ± 0.42 and 0.24 ± 0.20 μM, respectively, for compound 8), (IC50 = 0.12 ± 0.50, 0.79 ± 0.14 and 0.15± 0. 60 μM, respectively, for compound 10), in comparison with the reference drugs, erlotinib, sorafenib and roscovitine (IC50 = 0.18 ± 0.05, 1.58 ± 0.11 and 0.46 ± 0.30 μM, respectively). In addition, the docking study was simulated to afford better rationalization and put insight into the binding affinity between the promising derivatives and their targeted enzymes and that might be used as an optimum lead for further modification in the anticancer field.
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4
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Roychowdury H, Romero PA. Microfluidic deep mutational scanning of the human executioner caspases reveals differences in structure and regulation. Cell Death Dis 2022; 8:7. [PMID: 35013287 PMCID: PMC8748541 DOI: 10.1038/s41420-021-00799-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 12/02/2021] [Accepted: 12/14/2021] [Indexed: 12/19/2022]
Abstract
The human caspase family comprises 12 cysteine proteases that are centrally involved in cell death and inflammation responses. The members of this family have conserved sequences and structures, highly similar enzymatic activities and substrate preferences, and overlapping physiological roles. In this paper, we present a deep mutational scan of the executioner caspases CASP3 and CASP7 to dissect differences in their structure, function, and regulation. Our approach leverages high-throughput microfluidic screening to analyze hundreds of thousands of caspase variants in tightly controlled in vitro reactions. The resulting data provides a large-scale and unbiased view of the impact of amino acid substitutions on the proteolytic activity of CASP3 and CASP7. We use this data to pinpoint key functional differences between CASP3 and CASP7, including a secondary internal cleavage site, CASP7 Q196 that is not present in CASP3. Our results will open avenues for inquiry in caspase function and regulation that could potentially inform the development of future caspase-specific therapeutics.
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Affiliation(s)
| | - Philip A Romero
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA. .,Department of Chemical & Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA. .,The University of Wisconsin Carbone Cancer Center, Madison, WI, USA.
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5
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Araya LE, Soni IV, Hardy JA, Julien O. Deorphanizing Caspase-3 and Caspase-9 Substrates In and Out of Apoptosis with Deep Substrate Profiling. ACS Chem Biol 2021; 16:2280-2296. [PMID: 34553588 DOI: 10.1021/acschembio.1c00456] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Caspases are a family of enzymes that regulate biological processes such as inflammation and programmed cell death, through proteolysis. For example, in the intrinsic pathway of apoptosis, cell death signaling involves cytochrome c release from the mitochondria, which leads to the activation of caspase-9 and eventually the executioners caspase-3 and -7. One key step in our understanding of these proteases is to identify their respective protein substrates. Although hundreds of substrates have been linked to caspase-3, only a small handful of substrates have been reported for caspase-9. Employing deep profiling by subtiligase N-terminomics, we present here an unbiased analysis of caspase-3 and caspase-9 substrates in native cell lysates. We identified 906 putative protein substrates associated with caspase-3 and 124 protein substrates for caspase-9. This is the most comprehensive list of caspase substrates reported for each of these proteases, revealing a pool of new substrates that could not have been discovered using other approaches. Over half of the caspase-9 substrates were also cleaved by caspase-3, but often at unique sites, suggesting an evolved functional redundancy for these two proteases. Correspondingly, nearly half of the caspase-9 cleavage sites were not recognized by caspase-3. Our results suggest that in addition to its important role in activating the executioners, the role of caspase-9 is likely broader and more complex than previously appreciated, which includes proteolysis of key apoptotic substrates other than just caspase-3 and -7 and involvement in non-apoptotic pathways. Our results are well poised to aid the discovery of new biological functions for these two caspases.
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Affiliation(s)
- Luam E. Araya
- Department of Biochemistry, University of Alberta, Edmonton T6G 2H7, Alberta, Canada
| | - Ishankumar V. Soni
- Department of Chemistry, University of Massachusetts, Amherst 01003, Massachusetts, United States
| | - Jeanne A. Hardy
- Department of Chemistry, University of Massachusetts, Amherst 01003, Massachusetts, United States
| | - Olivier Julien
- Department of Biochemistry, University of Alberta, Edmonton T6G 2H7, Alberta, Canada
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6
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Soni IV, Hardy JA. Caspase-9 Activation of Procaspase-3 but Not Procaspase-6 Is Based on the Local Context of Cleavage Site Motifs and on Sequence. Biochemistry 2021; 60:2824-2835. [PMID: 34472839 DOI: 10.1021/acs.biochem.1c00459] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Studying the interactions between a protease and its protein substrates at a molecular level is crucial for identifying the factors facilitating selection of particular proteolytic substrates and not others. These selection criteria include both the sequence and the local context of the substrate cleavage site where the active site of the protease initially binds and then performs proteolytic cleavage. Caspase-9, an initiator of the intrinsic apoptotic pathway, mediates activation of executioner procaspase-3 by cleavage of the intersubunit linker (ISL) at site 172IETD↓S. Although procaspase-6, another executioner, possesses two ISL cleavage sites (site 1, 176DVVD↓N; site 2, 190TEVD↓A), neither is directly cut by caspase-9. Thus, caspase-9 directly activates procaspase-3 but not procaspase-6. To elucidate this selectivity of caspase-9, we engineered constructs of procaspase-3 (e.g., swapping the ISL site, 172IETD↓S, with DVVDN and TEVDA) and procaspase-6 (e.g., swapping site 1, 176DVVD↓N, and site 2, 190TEVD↓A, with IETDS). Using the substrate digestion data of these constructs, we show here that the P4-P1' sequence of procaspase-6 ISL site 1 (DVVDN) can be accessed but not cleaved by caspase-9. We also found that caspase-9 can recognize the P4-P1' sequence of procaspase-6 ISL site 2 (TEVDA); however, the local context of this cleavage site is the critical factor that prevents proteolytic cleavage. Overall, our data have demonstrated that both the sequence and the local context of the ISL cleavage sites play a vital role in preventing the activation of procaspase-6 directly by caspase-9.
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Affiliation(s)
- Ishankumar V Soni
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Jeanne A Hardy
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States.,Models to Medicine Center, Institute of Applied Life Sciences, University of Massachusetts, Amherst, Massachusetts 01003, United States
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7
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Moustafa GO, Shalaby A, Naglah AM, Mounier MM, El-Sayed H, Anwar MM, Nossier ES. Synthesis, Characterization, In Vitro Anticancer Potentiality, and Antimicrobial Activities of Novel Peptide-Glycyrrhetinic-Acid-Based Derivatives. Molecules 2021; 26:4573. [PMID: 34361728 PMCID: PMC8346995 DOI: 10.3390/molecules26154573] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/23/2021] [Accepted: 07/23/2021] [Indexed: 01/10/2023] Open
Abstract
Glycyrrhetinic acid (GA) is one of many interesting pentacyclic triterpenoids showing significant anticancer activity by triggering apoptosis in tumor cell lines. This study deals with the design and synthesis of new glycyrrhetinic acid (GA)-amino acid peptides and peptide ester derivatives. The structures of the new derivatives were established through various spectral and microanalytical data. The novel compounds were screened for their in vitro cytotoxic activity. The evaluation results showed that the new peptides produced promising cytotoxic activity against the human breast MCF-7 cancer cell line while comparing to doxorubicin. On the other hand, only compounds 3, 5, and 7 produced potent activity against human colon HCT-116 cancer cell line. The human liver cancer (HepG-2) cell line represented a higher sensitivity to peptide 7 (IC50; 3.30 μg/mL), while it appeared insensitive to the rest of the tested peptides. Furthermore, compounds 1, 3, and 5 exhibited a promising safety profile against human normal skin fibroblasts cell line BJ-1. In order to investigate the mode of action, compound 5 was selected as a representative example to study its in vitro effect against the apoptotic parameters and Bax/BCL-2/p53/caspase-7/caspase-3/tubulin, and DNA fragmentation to investigate beta (TUBb). Additionally, all the new analogues were subjected to antimicrobial assay against a panel of Gram-positive and Gram-negative bacteria and the yeast candida Albicans. All the tested GA analogues 1-8 exhibited more antibacterial effect against Micrococcus Luteus than gentamicin, but they exhibited moderate antimicrobial activity against the tested bacterial and yeast strains. Molecular docking studies were also simulated for compound 5 to give better rationalization and put insight to the features of its structure.
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Affiliation(s)
- Gaber O. Moustafa
- National Research Centre, Peptide Chemistry Department, Chemical Industries Research Division, Cairo 12622, Egypt;
| | - Ahmed Shalaby
- National Research Centre, Peptide Chemistry Department, Chemical Industries Research Division, Cairo 12622, Egypt;
| | - Ahmed M. Naglah
- National Research Centre, Peptide Chemistry Department, Chemical Industries Research Division, Cairo 12622, Egypt;
- Department of Pharmaceutical Chemistry, Drug Exploration and Development Chair (DEDC), College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia
| | - Marwa M. Mounier
- National Research Centre, Pharmacognosy Department, Pharmaceutical and Drug Industries Research Division, 33-El Bohouth St., Giza 12622, Egypt;
| | - Heba El-Sayed
- Botany and Microbiology Department, Faculty of Science, Helwan University, Helwan 11111, Egypt;
| | - Manal M. Anwar
- National Research Centre, Department of Therapeutic Chemistry, Cairo 12622, Egypt;
| | - Eman S. Nossier
- Department of Pharmaceutical Medicinal Chemistry and Drug Design, Faculty of Pharmacy (Girls), Al-Azhar University, Cairo 11754, Egypt;
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8
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Characterization of caspase-7 interaction with RNA. Biochem J 2021; 478:2681-2696. [PMID: 34156061 DOI: 10.1042/bcj20210366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/18/2021] [Accepted: 06/22/2021] [Indexed: 11/17/2022]
Abstract
Apoptosis is a regulated form of cell death essential to the removal of unwanted cells. At its core, a family of cysteine peptidases named caspases cleave key proteins allowing cell death to occur. To do so, each caspase catalytic pocket recognizes preferred amino acid sequences resulting in proteolysis, but some also use exosites to select and cleave important proteins efficaciously. Such exosites have been found in a few caspases, notably caspase-7 that has a lysine patch (K38KKK) that binds RNA, which acts as a bridge to RNA-binding proteins favoring proximity between the peptidase and its substrates resulting in swifter cleavage. Although caspase-7 interaction with RNA has been identified, in-depth characterization of this interaction is lacking. In this study, using in vitro cleavage assays, we determine that RNA concentration and length affect the cleavage of RNA-binding proteins. Additionally, using binding assays and RNA sequencing, we found that caspase-7 binds RNA molecules regardless of their type, sequence, or structure. Moreover, we demonstrate that the N-terminal peptide of caspase-7 reduces the affinity of the peptidase for RNA, which translates into slower cleavages of RNA-binding proteins. Finally, employing engineered heterodimers, we show that a caspase-7 dimer can use both exosites simultaneously to increase its affinity to RNA because a heterodimer with only one exosite has reduced affinity for RNA and cleavage efficacy. These findings shed light on a mechanism that furthers substrate recognition by caspases and provides potential insight into its regulation during apoptosis.
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9
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Makoni NJ, Nichols MR. The intricate biophysical puzzle of caspase-1 activation. Arch Biochem Biophys 2021; 699:108753. [PMID: 33453207 DOI: 10.1016/j.abb.2021.108753] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 12/22/2020] [Accepted: 01/05/2021] [Indexed: 12/13/2022]
Abstract
This review takes a closer look at the structural components of the molecules involved in the processes leading to caspase-1 activation. Interleukins 1β and 18 (IL-1β, IL-18) are well-known proinflammatory cytokines that are produced following cleavage of their respective precursor proteins by the cysteine protease caspase-1. Active caspase-1 is the final step of the NLRP3 inflammasome, a three-protein intracellular complex involved in inflammation and induction of pyroptosis (a proinflammatory cell-death process). NLRP3 activators facilitate assembly of the inflammasome complex and subsequent activation of caspase-1 by autoproteolysis. However, the definitive structural components of active caspase-1 are still unclear and new data add to the complexity of this process. This review outlines the historical and recent findings that provide supporting evidence for the structural aspects of caspase-1 autoproteolysis and activation.
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Affiliation(s)
- Nyasha J Makoni
- Department of Chemistry & Biochemistry, University of Missouri-St. Louis, St. Louis, MO, USA
| | - Michael R Nichols
- Department of Chemistry & Biochemistry, University of Missouri-St. Louis, St. Louis, MO, USA.
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10
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Resurrection of ancestral effector caspases identifies novel networks for evolution of substrate specificity. Biochem J 2020; 476:3475-3492. [PMID: 31675069 PMCID: PMC6874516 DOI: 10.1042/bcj20190625] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 10/30/2019] [Accepted: 11/01/2019] [Indexed: 12/18/2022]
Abstract
Apoptotic caspases evolved with metazoans more than 950 million years ago (MYA), and a series of gene duplications resulted in two subfamilies consisting of initiator and effector caspases. The effector caspase genes (caspases-3, -6, and -7) were subsequently fixed into the Chordata phylum more than 650 MYA when the gene for a common ancestor (CA) duplicated, and the three effector caspases have persisted throughout mammalian evolution. All caspases prefer an aspartate residue at the P1 position of substrates, so each caspase evolved discrete cellular roles through changes in substrate recognition at the P4 position combined with allosteric regulation. We examined the evolution of substrate specificity in caspase-6, which prefers valine at the P4 residue, compared with caspases-3 and -7, which prefer aspartate, by reconstructing the CA of effector caspases (AncCP-Ef1) and the CA of caspase-6 (AncCP-6An). We show that AncCP-Ef1 is a promiscuous enzyme with little distinction between Asp, Val, or Leu at P4. The specificity of caspase-6 was defined early in its evolution, where AncCP-6An demonstrates a preference for Val over Asp at P4. Structures of AncCP-Ef1 and of AncCP-6An show a network of charged amino acids near the S4 pocket that, when combined with repositioning a flexible active site loop, resulted in a more hydrophobic binding pocket in AncCP-6An. The ancestral protein reconstructions show that the caspase-hemoglobinase fold has been conserved for over 650 million years and that only three substitutions in the scaffold are necessary to shift substrate selection toward Val over Asp.
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11
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Boon L, Ugarte-Berzal E, Vandooren J, Opdenakker G. Protease propeptide structures, mechanisms of activation, and functions. Crit Rev Biochem Mol Biol 2020; 55:111-165. [PMID: 32290726 DOI: 10.1080/10409238.2020.1742090] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Proteases are a diverse group of hydrolytic enzymes, ranging from single-domain catalytic molecules to sophisticated multi-functional macromolecules. Human proteases are divided into five mechanistic classes: aspartate, cysteine, metallo, serine and threonine proteases, based on the catalytic mechanism of hydrolysis. As a protective mechanism against uncontrolled proteolysis, proteases are often produced and secreted as inactive precursors, called zymogens, containing inhibitory N-terminal propeptides. Protease propeptide structures vary considerably in length, ranging from dipeptides and propeptides of about 10 amino acids to complex multifunctional prodomains with hundreds of residues. Interestingly, sequence analysis of the different protease domains has demonstrated that propeptide sequences present higher heterogeneity compared with their catalytic domains. Therefore, we suggest that protease inhibition targeting propeptides might be more specific and have less off-target effects than classical inhibitors. The roles of propeptides, besides keeping protease latency, include correct folding of proteases, compartmentalization, liganding, and functional modulation. Changes in the propeptide sequence, thus, have a tremendous impact on the cognate enzymes. Small modifications of the propeptide sequences modulate the activity of the enzymes, which may be useful as a therapeutic strategy. This review provides an overview of known human proteases, with a focus on the role of their propeptides. We review propeptide functions, activation mechanisms, and possible therapeutic applications.
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Affiliation(s)
- Lise Boon
- Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, Laboratory of Immunobiology, KU Leuven, Leuven, Belgium
| | - Estefania Ugarte-Berzal
- Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, Laboratory of Immunobiology, KU Leuven, Leuven, Belgium
| | - Jennifer Vandooren
- Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, Laboratory of Immunobiology, KU Leuven, Leuven, Belgium
| | - Ghislain Opdenakker
- Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, Laboratory of Immunobiology, KU Leuven, Leuven, Belgium
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12
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Caspase-7 uses RNA to enhance proteolysis of poly(ADP-ribose) polymerase 1 and other RNA-binding proteins. Proc Natl Acad Sci U S A 2019; 116:21521-21528. [PMID: 31586028 PMCID: PMC6815152 DOI: 10.1073/pnas.1909283116] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
During apoptosis, hundreds of intracellular proteins are cleaved by caspases. In addition to recognizing optimized motifs in the primary structure of its substrates, we show that caspase-7 possesses an exosite to enhance poly(ADP-ribose) polymerase 1 (PARP-1) recognition via the mutual binding of RNA. We also demonstrate that caspase-7 binds RNA and that PARP-1, via 2 RNA-binding domains, likely binds the same RNA molecule, bringing itself near caspase-7 for prompt inactivation. This mechanism is conserved in the mouse ortholog. We have also validated the use of RNA for the efficient cleavage of 6 other RNA-BPs, demonstrating that this distinctive mode of proteolysis enhancement by caspase-7 is an essential feature of substrate recognition during apoptosis. To achieve swift cell demise during apoptosis, caspases cleave essential proteins for cell survival and removal. In addition to the binding of preferred amino acid sequences to its substrate-binding pocket, caspase-7 also uses exosites to select specific substrates. 4 lysine residues (K38KKK) located in the N-terminal domain of caspase-7 form such an exosite and promote the rapid proteolysis of the poly(ADP-ribose) polymerase 1 (PARP-1), but the mechanism of recognition remains mostly unknown. In this study, we show that the overall positive charge of the exosite is the critical feature of this evolutionarily conserved binding site. Additionally, interaction with the caspase-7 exosite involves both the Zn3 and BRCT domains of PARP-1 and is mediated by RNA. Indeed, PARP-1 proteolysis efficacy is sensitive to RNase A and promoted by added RNA. Moreover, using affinity chromatography and gel shift assays, we demonstrate that caspase-7, but not caspase-3 or a caspase-7 with a mutated exosite, binds nucleic acids. Finally, we show that caspase-7 prefers RNA-binding proteins (RNA-BPs) as substrates compared to caspase-3 and that RNA enhances proteolysis by caspase-7 of many of these RNA-BPs. Thus, we have uncovered an unusual way by which caspase-7 selects and cleaves specific substrates.
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13
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Kassem AF, Moustafa GO, Nossier ES, Khalaf HS, Mounier MM, Al-Yousef SA, Mahmoud SY. In vitro anticancer potentiality and molecular modelling study of novel amino acid derivatives based on N1, N3-bis-(1-hydrazinyl-1-oxopropan-2-yl) isophthalamide. J Enzyme Inhib Med Chem 2019; 34:1247-1258. [PMID: 31286782 PMCID: PMC6691786 DOI: 10.1080/14756366.2019.1613390] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
A series of N1,N3-bis (1-oxopropan-2-yl) isophthalamide-based derivatives 4–16 were prepared and their structures were confirmed by different spectral tools. The cytotoxic potentiality of novel compounds 4–16 was assessed by the MTT assay method on colon, lung and breast tumour cell lines. Compound 5 gave the most significant specificity anticancer activity with safety response on normal cell lines. In vitro enzyme assay and several apoptotic parameters were examined to elucidate the mode of action of compound 5. Molecular docking studies also were simulated to put insight and give better understanding to its structural features.
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Affiliation(s)
- Asmaa F Kassem
- a Department of Chemistry of Natural and Microbial Products, Pharmaceutical and Drug Industries Research Division , National Research Centre , Giza , Egypt
| | - Gaber O Moustafa
- b Department of Peptide Chemistry, Chemical Industries Research Division , National Research Centre , Cairo , Egypt
| | - Eman S Nossier
- c Department of Pharmaceutical Medicinal Chemistry, Faculty of Pharmacy (Girls) , Al-Azhar University , Cairo , Egypt
| | - Hemat S Khalaf
- d Department of Chemistry , College of Science and Arts, Jouf University , Al Qurayat , Saudi Arabia.,e Chemical Industries Research Division, Department of Photochemistry , National Research Centre , Cairo , Egypt
| | - Marwa M Mounier
- f Pharmaceutical and Drug Industries Research Division, Department of Pharmacognosy , National Research Centre , Giza , Egypt
| | - Suliman A Al-Yousef
- g Department of Clinical Laboratory Science, College of Applied Medical Science , University of Hafr Al Batin , Hafr Al Batin , Saudi Arabia
| | - Sabry Y Mahmoud
- h Department of Biology , College of Science, University of Hafr Al Batin , Hafr Al Batin , Saudi Arabia
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14
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Gonçalves AV, Margolis SR, Quirino GFS, Mascarenhas DPA, Rauch I, Nichols RD, Ansaldo E, Fontana MF, Vance RE, Zamboni DS. Gasdermin-D and Caspase-7 are the key Caspase-1/8 substrates downstream of the NAIP5/NLRC4 inflammasome required for restriction of Legionella pneumophila. PLoS Pathog 2019; 15:e1007886. [PMID: 31251782 PMCID: PMC6622555 DOI: 10.1371/journal.ppat.1007886] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 07/11/2019] [Accepted: 06/03/2019] [Indexed: 11/24/2022] Open
Abstract
Inflammasomes are cytosolic multi-protein complexes that detect infection or cellular damage and activate the Caspase-1 (CASP1) protease. The NAIP5/NLRC4 inflammasome detects bacterial flagellin and is essential for resistance to the flagellated intracellular bacterium Legionella pneumophila. The effectors required downstream of NAIP5/NLRC4 to restrict bacterial replication remain unclear. Upon NAIP5/NLRC4 activation, CASP1 cleaves and activates the pore-forming protein Gasdermin-D (GSDMD) and the effector caspase-7 (CASP7). However, Casp1–/– (and Casp1/11–/–) mice are only partially susceptible to L. pneumophila and do not phenocopy Nlrc4–/–mice, because NAIP5/NLRC4 also activates CASP8 for restriction of L. pneumophila infection. Here we show that CASP8 promotes the activation of CASP7 and that Casp7/1/11–/– and Casp8/1/11–/– mice recapitulate the full susceptibility of Nlrc4–/– mice. Gsdmd–/– mice exhibit only mild susceptibility to L. pneumophila, but Gsdmd–/–Casp7–/– mice are as susceptible as the Nlrc4–/– mice. These results demonstrate that GSDMD and CASP7 are the key substrates downstream of NAIP5/NLRC4/CASP1/8 required for resistance to L. pneumophila. Inflammasomes are multi-protein complexes that detect infection and other stimuli and activate the Caspase-1 (CASP1) protease. The effectors required downstream of NAIP5/NLRC4 to restrict bacterial replication remain unclear. Active CASP1 cleaves and activates the pore-forming protein gasdermin D (GSDMD) to induce inflammation and cell death. We have previously shown that CASP8 is activated by the NAIP5/NLRC4 inflammasome independently of CASP1 and functions to restrict replication of the intracellular bacterium Legionella pneumophila. Here, we show that CASP7 is activated downstream of CASP8 and is required for CASP8-dependent restriction of L. pneumophila replication in macrophages and in vivo. In addition, CASP7 is also activated by CASP1. Taken together, these results imply that CASP7 and GSDMD are the two key caspase substrates downstream of NAIP5/NLRC4. In support of this hypothesis, we found that mice double deficient in CASP7 and GSDMD are more susceptible than the single knockouts and are as susceptible as the Nlrc4 deficient mice for restriction of L. pneumophila replication in vivo. Collectively, our data indicate that GSDMD and CASP7 are activated by CASP1 and induce cell death and restriction of bacterial infection. Therefore, GSDMD and multiple caspases (CASP1, CASP7 and CASP8) operate downstream of the NAIP5/NLRC4 inflammasome for restriction of infection by pathogenic bacteria.
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Affiliation(s)
- Augusto V. Gonçalves
- Department of Cell Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Shally R. Margolis
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, and Cancer Research Laboratory, University of California, Berkeley, California, United States of America
| | - Gustavo F. S. Quirino
- Department of Cell Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Danielle P. A. Mascarenhas
- Department of Cell Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Isabella Rauch
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, and Cancer Research Laboratory, University of California, Berkeley, California, United States of America
| | - Randilea D. Nichols
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, and Cancer Research Laboratory, University of California, Berkeley, California, United States of America
| | - Eduard Ansaldo
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, and Cancer Research Laboratory, University of California, Berkeley, California, United States of America
| | - Mary F. Fontana
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, and Cancer Research Laboratory, University of California, Berkeley, California, United States of America
| | - Russell E. Vance
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, and Cancer Research Laboratory, University of California, Berkeley, California, United States of America
- Howard Hughes Medical Institute, University of California, Berkeley, California, United States of America
- * E-mail: (REV); (DSZ)
| | - Dario S. Zamboni
- Department of Cell Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- * E-mail: (REV); (DSZ)
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15
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Rashdan HRM, Farag MM, El-Gendey MS, Mounier MM. Toward Rational Design of Novel Anti-Cancer Drugs Based on Targeting, Solubility, and Bioavailability Exemplified by 1,3,4-Thiadiazole Derivatives Synthesized Under Solvent-Free Conditions. Molecules 2019; 24:molecules24132371. [PMID: 31252614 PMCID: PMC6651776 DOI: 10.3390/molecules24132371] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 06/17/2019] [Accepted: 06/19/2019] [Indexed: 01/23/2023] Open
Abstract
The 1,3,4-thiadiazole derivatives (9a–i) were synthesized under solvent free conditions and their chemical composition was confirmed using different spectral tools (IR, Mass, and NMR spectrometry). All the synthesized compounds were screened for their anti-cancer potentiality over human breast carcinoma (MCF-7) and human lung carcinoma (A-549). Most of the tested compounds showed remarkable anti-breast cancer activity. However, compound 4 showed the most anti-lung cancer activity. Then, compounds with cytotoxic activity ≥ 80% over breast and lung cells were subjected to investigate their specificity on human normal skin cell line (BJ-1). Compounds 9b and 9g were chosen owing to their high breast anti-cancer efficacy and their safety, in order to study the possible anti-cancer mode of action. Otherwise, drug delivery provides a means to overcome the low solubility, un-targeted release, and limited bioavailability of the prepared 1,3,4-thiadiazole drug-like substances. Compounds 9b and 9g were chosen to be encapsulated in Na-alginate microspheres. The release profile and mechanism of both compounds were investigated, and the results revealed that the release profiles of both microspheres showed a sustained release, and the release mechanism was controlled by Fickian diffusion. Accordingly, these compounds are promising for their use in chemotherapy for cancer treatment, and their hydrophilicity was improved by polymer encapsulation to become more effective in their pharmaceutical application.
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Affiliation(s)
- Huda R M Rashdan
- Chemistry of Natural and Microbial Products Department, Pharmaceutical and Drug Industries Research Division, National Research Centre, Dokki, Cairo 12622, Egypt.
| | - Mohammad M Farag
- Glass Research Department, National Research Centre, 33 El-Behooth Str., Dokki, Cairo 12622, Egypt
| | - Marwa S El-Gendey
- Chemistry Department, Faculty of Science "Girls", Al-Azhar University, Cairo 11754, Egypt
- Chemistry Department, Faculty of College, Turabah, Taif University, Taif 21974, Saudi Arabia
| | - Marwa M Mounier
- Pharmacognosy Department, Pharmaceutical and Drug Industries Research Division, National Research Centre, Dokki, Cairo 12622, Egypt
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16
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Caspase-9 CARD : core domain interactions require a properly formed active site. Biochem J 2018; 475:1177-1196. [PMID: 29500231 DOI: 10.1042/bcj20170913] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 02/27/2018] [Accepted: 03/01/2018] [Indexed: 12/20/2022]
Abstract
Caspase-9 is a critical factor in the initiation of apoptosis and as a result is tightly regulated by many mechanisms. Caspase-9 contains a Caspase Activation and Recruitment Domain (CARD), which enables caspase-9 to form a tight interaction with the apoptosome, a heptameric activating platform. The caspase-9 CARD has been thought to be principally involved in recruitment to the apoptosome, but its roles outside this interaction have yet to be uncovered. In this work, we show that the CARD is involved in physical interactions with the catalytic core of caspase-9 in the absence of the apoptosome; this interaction requires a properly formed caspase-9 active site. The active sites of caspases are composed of four extremely mobile loops. When the active-site loops are not properly ordered, the CARD and core domains of caspase-9 do not interact and behave independently, like loosely tethered beads. When the active-site loop bundle is properly ordered, the CARD domain interacts with the catalytic core, forming a single folding unit. Taken together, these findings provide mechanistic insights into a new level of caspase-9 regulation, prompting speculation that the CARD may also play a role in the recruitment or recognition of substrate.
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17
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Thomas ME, Grinshpon R, Swartz P, Clark AC. Modifications to a common phosphorylation network provide individualized control in caspases. J Biol Chem 2018; 293:5447-5461. [PMID: 29414778 DOI: 10.1074/jbc.ra117.000728] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 01/24/2018] [Indexed: 11/06/2022] Open
Abstract
Caspase-3 activation and function have been well-defined during programmed cell death, but caspase activity, at low levels, is also required for developmental processes such as lymphoid proliferation and erythroid differentiation. Post-translational modification of caspase-3 is one method used by cells to fine-tune activity below the threshold required for apoptosis, but the allosteric mechanism that reduces activity is unknown. Phosphorylation of caspase-3 at a conserved allosteric site by p38-MAPK (mitogen-activated protein kinase) promotes survival in human neutrophils, and the modification of the loop is thought to be a key regulator in many developmental processes. We utilized phylogenetic, structural, and biophysical studies to define the interaction networks that facilitate the allosteric mechanism in caspase-3. We show that, within the modified loop, Ser150 evolved with the apoptotic caspases, whereas Thr152 is a more recent evolutionary event in mammalian caspase-3. Substitutions at Ser150 result in a pH-dependent decrease in dimer stability, and localized changes in the modified loop propagate to the active site of the same protomer through a connecting surface helix. Likewise, a cluster of hydrophobic amino acids connects the conserved loop to the active site of the second protomer. The presence of Thr152 in the conserved loop introduces a "kill switch" in mammalian caspase-3, whereas the more ancient Ser150 reduces without abolishing enzyme activity. These data reveal how evolutionary changes in a conserved allosteric site result in a common pathway for lowering activity during development or a more recent cluster-specific switch to abolish activity.
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Affiliation(s)
- Melvin E Thomas
- From the Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27608 and
| | - Robert Grinshpon
- From the Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27608 and
| | - Paul Swartz
- From the Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27608 and
| | - A Clay Clark
- the Department of Biology, University of Texas, Arlington, Texas 76019
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18
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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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19
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MicroRNA-146a down-regulation correlates with neuroprotection and targets pro-apoptotic genes in cerebral ischemic injury in vitro. Brain Res 2016; 1648:136-143. [PMID: 27449900 DOI: 10.1016/j.brainres.2016.07.034] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Revised: 07/11/2016] [Accepted: 07/19/2016] [Indexed: 12/25/2022]
Abstract
MicroRNAs (miRNAs) are short, non-coding RNAs that negatively regulate target gene expression, and play an important role in cerebral ischemic injury. MiR-146a has been reported to be highly related to cell invasion, metastasis, immunity, inflammation and apoptosis. Previous studies have indicated that miR-146a can either inhibit or promote apoptosis through different pathophysiological processes. In our previous study, miR-146a in the blood was down-regulated during acute ischemic stroke. However, the connection between miR-146a and acute cerebral ischemic injury and the mechanism underlying the connection remain unclear. Here, we aimed to investigate the role of miR-146a and its possible target genes in human SK-N-SH cells subjected to 16h of oxygen-glucose deprivation and 12h of reperfusion (OGD/R) injury. Cells were transfected with miR-146a mimic or inhibitor to alter the expression of miR-146a. MiR-146a in the SK-N-SH cells was down-regulated after OGD/R injury. Moreover, bioinformatics analysis and dual luciferase assays demonstrated that miR-146a directly recognized the 3'-UTR of the pro-apoptotic genes, Caspase7 and Bcl-2-associated transcription factor 1 (Bclaf1). Furthermore, miR-146a over-expression effectively decreased the mRNA and protein expression of Caspase7 and Bclaf1, and aggravated OGD/R-induced cell apoptosis; in contrast, miR-146a down-regulation was neuroprotective. In conclusion, our study revealed that miR-146a contributes to OGD/R injury in vitro, while negatively regulating the pro-apoptotic genes, Caspase7 and Bclaf1. This special mechanism provides new insight into miRNA regulatory networks. In addition, miR-146a may offer a potential therapeutic approach to cerebral ischemic injury.
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20
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Protective effect of magnesium acetyltaurate against endothelin-induced retinal and optic nerve injury. Neuroscience 2016; 325:153-64. [PMID: 27012609 DOI: 10.1016/j.neuroscience.2016.03.041] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/14/2016] [Accepted: 03/15/2016] [Indexed: 12/27/2022]
Abstract
Vascular dysregulation has long been recognized as an important pathophysiological factor underlying the development of glaucomatous neuropathy. Endothelin-1 (ET1) has been shown to be a key player due to its potent vasoconstrictive properties that result in retinal ischemia and oxidative stress leading to retinal ganglion cell (RGC) apoptosis and optic nerve (ON) damage. In this study we investigated the protective effects of magnesium acetyltaurate (MgAT) against retinal cell apoptosis and ON damage. MgAT was administered intravitreally prior to, along with or after administration of ET1. Seven days post-injection, animals were euthanized and retinae were subjected to morphometric analysis, TUNEL and caspase-3 staining. ON sections were stained with toluidine blue and were graded for neurodegenerative effects. Oxidative stress was also estimated in isolated retinae. Pre-treatment with MgAT significantly lowered ET1-induced retinal cell apoptosis as measured by retinal morphometry and TUNEL staining. This group of animals also showed significantly lesser caspase-3 activation and significantly reduced retinal oxidative stress compared to the animals that received intravitreal injection of only ET1. Additionally, the axonal degeneration in ON was markedly reduced in MgAT pretreated animals. The animals that received MgAT co- or post-treatment with ET1 also showed improvement in all parameters; however, the effects were not as significant as observed in MgAT pretreated animals. The current study showed that the intravitreal pre-treatment with MgAT reduces caspase-3 activation and prevents retinal cell apoptosis and axon loss in ON induced by ET1. This protective effect of ET1 was associated with reduced retinal oxidative stress.
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21
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McLuskey K, Grewal JS, Das D, Godzik A, Lesley SA, Deacon AM, Coombs GH, Elsliger MA, Wilson IA, Mottram JC. Crystal Structure and Activity Studies of the C11 Cysteine Peptidase from Parabacteroides merdae in the Human Gut Microbiome. J Biol Chem 2016; 291:9482-91. [PMID: 26940874 PMCID: PMC4850288 DOI: 10.1074/jbc.m115.706143] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Indexed: 11/21/2022] Open
Abstract
Clan CD cysteine peptidases, a structurally related group of peptidases that include mammalian caspases, exhibit a wide range of important functions, along with a variety of specificities and activation mechanisms. However, for the clostripain family (denoted C11), little is currently known. Here, we describe the first crystal structure of a C11 protein from the human gut bacterium, Parabacteroides merdae (PmC11), determined to 1.7-Å resolution. PmC11 is a monomeric cysteine peptidase that comprises an extended caspase-like α/β/α sandwich and an unusual C-terminal domain. It shares core structural elements with clan CD cysteine peptidases but otherwise structurally differs from the other families in the clan. These studies also revealed a well ordered break in the polypeptide chain at Lys147, resulting in a large conformational rearrangement close to the active site. Biochemical and kinetic analysis revealed Lys147 to be an intramolecular processing site at which cleavage is required for full activation of the enzyme, suggesting an autoinhibitory mechanism for self-preservation. PmC11 has an acidic binding pocket and a preference for basic substrates, and accepts substrates with Arg and Lys in P1 and does not require Ca2+ for activity. Collectively, these data provide insights into the mechanism and activity of PmC11 and a detailed framework for studies on C11 peptidases from other phylogenetic kingdoms.
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Affiliation(s)
- Karen McLuskey
- From the Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom
| | - Jaspreet S Grewal
- From the Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom, the Department of Biology, Centre for Immunology and Infection, University of York, Wentworth Way, Heslington, York YO10 5DD, United Kingdom
| | - Debanu Das
- the Joint Center for Structural Genomics, the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025
| | - Adam Godzik
- the Joint Center for Structural Genomics, the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, the Program on Bioinformatics and Systems Biology, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037
| | - Scott A Lesley
- the Joint Center for Structural Genomics, the Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92037, the Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, and
| | - Ashley M Deacon
- the Joint Center for Structural Genomics, the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025
| | - Graham H Coombs
- the Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, United Kingdom
| | - Marc-André Elsliger
- the Joint Center for Structural Genomics, the Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Ian A Wilson
- the Joint Center for Structural Genomics, the Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92037,
| | - Jeremy C Mottram
- From the Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, United Kingdom, the Department of Biology, Centre for Immunology and Infection, University of York, Wentworth Way, Heslington, York YO10 5DD, United Kingdom,
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22
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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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23
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Yakovlev AA, Gulyaeva NV. Possible role of proteases in preconditioning of brain cells to pathological conditions. BIOCHEMISTRY (MOSCOW) 2015; 80:163-71. [PMID: 25756531 DOI: 10.1134/s0006297915020030] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Preconditioning (PC) is one of the most effective strategies to reduce the severity of cell damage, in particular of nervous tissue cells. Although PC mechanisms are studied insufficiently, it is clear that proteases are involved in them, but their role has yet been not studied in detail. In this work, some mechanisms of a potential recruiting of proteases in PC are considered. Our attention is mainly focused on the protease families of caspases and cathepsins and on protease receptors. We present evidence that just these proteins are involved in the PC of brain cells. A hypothesis is proposed that secreted cathepsin B is involved in the realization of PC through activation of PAR2 receptor.
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Affiliation(s)
- A A Yakovlev
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, 117485, Russia.
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24
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McLuskey K, Mottram J. Comparative structural analysis of the caspase family with other clan CD cysteine peptidases. Biochem J 2015; 466:219-32. [PMID: 25697094 PMCID: PMC4357240 DOI: 10.1042/bj20141324] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 11/19/2014] [Accepted: 12/08/2014] [Indexed: 11/29/2022]
Abstract
Clan CD forms a structural group of cysteine peptidases, containing seven individual families and two subfamilies of structurally related enzymes. Historically, it is most notable for containing the mammalian caspases, on which the structures of the clan were founded. Interestingly, the caspase family is split into two subfamilies: the caspases, and a second subfamily containing both the paracaspases and the metacaspases. Structural data are now available for both the paracaspases and the metacaspases, allowing a comprehensive structural analysis of the entire caspase family. In addition, a relative plethora of structural data has recently become available for many of the other families in the clan, allowing both the structures and the structure-function relationships of clan CD to be fully explored. The present review compares the enzymes in the caspase subfamilies with each other, together with a comprehensive comparison of all the structural families in clan CD. This reveals a diverse group of structures with highly conserved structural elements that provide the peptidases with a variety of substrate specificities and activation mechanisms. It also reveals conserved structural elements involved in substrate binding, and potential autoinhibitory functions, throughout the clan, and confirms that the metacaspases are structurally diverse from the caspases (and paracaspases), suggesting that they should form a distinct family of clan CD peptidases.
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Key Words
- caspase
- clan cd
- crystallography
- metacaspase
- peptidase
- protein structure
- ap, activation peptide
- card, caspase recruitment domain
- chf, caspase/haemoglobinase fold
- cpd, cysteine peptidase domain
- csd, c-terminal subdomain
- dd, death domain
- ded, death effector domain
- insp6, myo-inositol hexakisphosphate
- lsam, legumain stabilization and activity modulation
- lsd1, lesion-simulating disease 1
- malt1, mucosa-associated lymphoid tissue translocation protein 1
- martx, multi-functional, autoprocessing repeat in toxin
- rmsd, root-mean-square deviation
- sse, secondary structural element
- xiap, x-linked inhibitor of apoptosis
- z-vrpr-fmk, benzoxycarbonyl-val-arg-pro-arg-fluoromethylketone
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Affiliation(s)
- Karen McLuskey
- *Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - Jeremy C. Mottram
- *Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
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25
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McStay GP, Green DR. Identification of active caspases using affinity-based probes. Cold Spring Harb Protoc 2014; 2014:856-60. [PMID: 25086016 DOI: 10.1101/pdb.prot080309] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Small-molecule inhibitors of caspases can be modified with moieties such as biotin or fluorescent molecules. After the inhibitor molecule has bound to an active caspase, the caspase itself becomes labeled and can be isolated using affinity purification. This protocol describes the use of the biotinylated pan-caspase inhibitor VAD-FMK and streptavidin beads to isolate active caspases. These caspases are then separated by gel electrophoresis and identified with caspase-specific antibodies using western blotting techniques. Other caspase inhibitors bound with biotin or other labels can be substituted in this assay; labeled inhibitors are available commercially as either pan-caspase or caspase-specific probes.
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Affiliation(s)
- Gavin P McStay
- Department of Life Sciences, New York Institute of Technology, Old Westbury, New York 11568
| | - Douglas R Green
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
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26
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IL-15 maintains T-cell survival via S-nitrosylation-mediated inhibition of caspase-3. Cell Death Differ 2014; 21:904-14. [PMID: 24510126 DOI: 10.1038/cdd.2014.10] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 12/27/2013] [Accepted: 01/08/2014] [Indexed: 12/18/2022] Open
Abstract
Caspase activity is critical for both T-cell survival and death. However, little is known regarding what determines caspase activity in cycling T cells. Interleukin (IL)-2 and IL-15 confer very different susceptibilities to T-cell death. We therefore considered that IL-2 and IL-15 differentially regulate caspase activity to influence T-cell survival. We observed that IL-2-cultured primary murine effector T cells manifested elevated levels of caspase-3 activity compared with IL-15-cultured T cells. T cell receptor (TCR) restimulation further increased caspase activity and induced considerable cell death in IL-2-cultured T cells, but provoked only a minimal increase of caspase activity and cell death in IL-15-cultured T cells. IL-2 sensitization to cell death was caspase-3 mediated. Interestingly, increased active caspase-3 levels with IL-2 were independent of active initiator caspase-8 and caspase-9 that were similar with IL-2 and IL-15. Rather, caspase-3 activity was inhibited by posttranslational S-nitrosylation in IL-15-cultured T cells, but not in the presence of IL-2. This paralleled increased reactive nitrogen and oxygen species with IL-15 and reduced glycolysis. Taken together, these data suggest that the metabolic state conferred by IL-15 inhibits T-cell apoptosis in part by maintaining low levels of active caspase-3 via S-nitrosylation.
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Abstract
Apical caspases 8, 9, and 10 are only active as dimers. These dimers are unstable, and to characterize their activity they need to be maintained in vitro in a dimeric state. We provide updated methods for those looking to characterize various aspects of caspase function. We describe full methods for those looking to activate caspases in vitro using kosmotropic reagents, an essential step in characterizing upstream (apical) caspases. We detail methods for fusion of caspase domains to engineered dimerization domains as an alternative method to trigger regulated dimerization of caspases. We also describe methods to determine caspase activity profiles in cells and provide methods for studying the ability of SMAC-mimetic reagents to release inhibition of caspases by IAPs.
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Affiliation(s)
- Peter D Mace
- Biochemistry Department, University of Otago, Dunedin, New Zealand
| | - Stefan J Riedl
- Program in Cell Death and Survival Networks, NCI Designated Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, USA
| | - Guy S Salvesen
- Program in Cell Death and Survival Networks, NCI Designated Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, USA.
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Lin YF, Lai TC, Chang CK, Chen CL, Huang MS, Yang CJ, Liu HG, Dong JJ, Chou YA, Teng KH, Chen SH, Tian WT, Jan YH, Hsiao M, Liang PH. Targeting the XIAP/caspase-7 complex selectively kills caspase-3-deficient malignancies. J Clin Invest 2013; 123:3861-75. [PMID: 23979166 DOI: 10.1172/jci67951] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 06/21/2013] [Indexed: 01/06/2023] Open
Abstract
Caspase-3 downregulation (CASP3/DR) in tumors frequently confers resistance to cancer therapy and is significantly correlated with a poor prognosis in cancer patients. Because CASP3/DR cancer cells rely heavily on the activity of caspase-7 (CASP7) to initiate apoptosis, inhibition of activated CASP7 (p19/p12-CASP7) by X-linked inhibitor of apoptosis protein (XIAP) is a potential mechanism by which apoptosis is prevented in those cancer cells. Here, we identify the pocket surrounding the Cys246 residue of p19/p12-CASP7 as a target for the development of a protein-protein interaction (PPI) inhibitor of the XIAP:p19/p12-CASP7 complex. Interrupting this PPI directly triggered CASP7-dependent apoptotic signaling that bypassed the activation of the apical caspases and selectively killed CASP3/DR malignancies in vitro and in vivo without adverse side effects in nontumor cells. Importantly, CASP3/DR combined with p19/p12-CASP7 accumulation correlated with the aggressive evolution of clinical malignancies and a poor prognosis in cancer patients. Moreover, targeting of this PPI effectively killed cancer cells with multidrug resistance due to microRNA let-7a-1-mediated CASP3/DR and resensitized cancer cells to chemotherapy-induced apoptosis. These findings not only provide an opportunity to treat CASP3/DR malignancies by targeting the XIAP:p19/p12-CASP7 complex, but also elucidate the molecular mechanism underlying CASP3/DR in cancers.
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Affiliation(s)
- Yuan-Feng Lin
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
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29
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MacKenzie SH, Schipper JL, England EJ, Thomas ME, Blackburn K, Swartz P, Clark AC. Lengthening the intersubunit linker of procaspase 3 leads to constitutive activation. Biochemistry 2013; 52:6219-31. [PMID: 23941397 DOI: 10.1021/bi400793s] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The conformational ensemble of procaspase 3, the primary executioner in apoptosis, contains two major forms, inactive and active, with the inactive state favored in the native ensemble. A region of the protein known as the intersubunit linker (IL) is cleaved during maturation, resulting in movement of the IL out of the dimer interface and subsequent active site formation (activation-by-cleavage mechanism). We examined two models for the role of the IL in maintaining the inactive conformer, an IL-extension model versus a hydrophobic cluster model, and we show that increasing the length of the IL by introducing 3-5 alanines results in constitutively active procaspases. Active site labeling and subsequent analyses by mass spectrometry show that the full-length zymogen is enzymatically active. We also show that minor populations of alternately cleaved procaspase result from processing at D169 when the normal cleavage site, D175, is unavailable. Importantly, the alternately cleaved proteins have little to no activity, but increased flexibility of the linker increases the exposure of D169. The data show that releasing the strain of the short IL, in and of itself, is not sufficient to populate the active conformer of the native ensemble. The IL must also allow for interactions that stabilize the active site, possibly from a combination of optimal length, flexibility in the IL, and specific contacts between the IL and interface. The results provide further evidence that substantial energy is required to shift the protein to the active conformer. As a result, the activation-by-cleavage mechanism dominates in the cell.
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Affiliation(s)
- Sarah H MacKenzie
- 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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Kang HJ, Lee YM, Bae KH, Kim SJ, Chung SJ. Structural asymmetry of procaspase-7 bound to a specific inhibitor. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:1514-21. [PMID: 23897474 DOI: 10.1107/s0907444913010196] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 04/14/2013] [Indexed: 02/26/2023]
Abstract
Caspase-7 is expressed as a proenzyme and is activated by initiator caspases upon the transmission of cell-death signals. Despite extensive structural and biochemical analyses, many questions regarding the mechanism of caspase-7 activation remain unanswered. Caspase-7 is auto-activated during overexpression in Escherichia coli, even in the absence of initiator caspases, indicating that procaspase-7 has intrinsic catalytic activity. When variants of procaspase-7 with altered L2 loops were prepared, a variant with six inserted amino acids showed meaningful catalytic activity which was inhibited by Ac-DEVD-CHO. The kinetic constants of the procaspase-7 variant were determined and its three-dimensional structure was solved with and without bound inhibitor. The homodimeric procaspase-7 bound to the inhibitor revealed an asymmetry. One monomer formed a complete active site bound to the inhibitor in collaboration with the L2 loop from the other monomer, whereas the other monomer had an incomplete active site despite the bound inhibitor. Consequently, the two L2 loops in homodimeric procaspase-7 served as inherent L2 and L2' loops forming one complete active site. These data represent the first three-dimensional structure of a procaspase-7 variant bound to a specific inhibitor, Ac-DEVD-CHO, and provide insight into the folding mechanism during caspase-7 activation and the basal activity level of procaspase-7.
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Affiliation(s)
- Hyo Jin Kang
- Department of Chemistry, College of Natural Science, Dongguk University, 26 Pil-dong 3-ga, Jung-gu, Seoul 100-715, Republic of Korea
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31
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Ching B, Chen XL, Yong JHA, Wilson JM, Hiong KC, Sim EWL, Wong WP, Lam SH, Chew SF, Ip YK. Increases in apoptosis, caspase activity and expression of p53 and bax, and the transition between two types of mitochondrion-rich cells, in the gills of the climbing perch, Anabas testudineus, during a progressive acclimation from freshwater to seawater. Front Physiol 2013; 4:135. [PMID: 23760020 PMCID: PMC3675322 DOI: 10.3389/fphys.2013.00135] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 05/21/2013] [Indexed: 01/17/2023] Open
Abstract
This study aimed to test the hypothesis that branchial osmoregulatory acclimation involved increased apoptosis and replacement of mitochdonrion-rich cells (MRCs) in the climbing perch, Anabas testudineus, during a progressive acclimation from freshwater to seawater. A significant increase in branchial caspase-3/-7 activity was observed on day 4 (salinity 20), and an extensive TUNEL-positive apoptosis was detected on day 5 (salinity 25), indicating salinity-induced apoptosis had occurred. This was further supported by an up-regulation of branchial mRNA expression of p53, a key regulator of cell cycle arrest and apoptosis, between day 2 (salinity 10) and day 6 (seawater), and an increase in branchial p53 protein abundance on day 6. Seawater acclimation apparently activated both the extrinsic and intrinsic pathways, as reflected by significant increases in branchial caspase-8 and caspase-9 activities. The involvement of the intrinsic pathway was confirmed by the significant increase in branchial mRNA expression of bax between day 4 (salinity 20) and day 6 (seawater). Western blotting results revealed the presence of a freshwater Na(+)/K(+)-ATPase (Nka) α-isoform, Nka α1a, and a seawater isoform, Nka α1b, the protein abundance of which decreased and increased, respectively, during seawater acclimation. Immunofluorescence microscopy revealed the presence of two types of MRCs distinctly different in sizes, and confirmed that the reduction in Nka α1a expression, and the prominent increases in expression of Nka α1b, Na(+):K(+):2Cl(-) cotransporter 1, and cystic fibrosis transmembrane conductance regulator Cl(-) channel coincided with the salinity-induced apoptotic event. Since modulation of existing MRCs alone could not have led to extensive salinity-induced apoptosis, it is probable that some, if not all, freshwater-type MRCs could have been removed through increased apoptosis and subsequently replaced by seawater-type MRCs in the gills of A. testudineus during seawater acclimation.
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Affiliation(s)
- Biyun Ching
- Department of Biological Science, National University of Singapore Kent Ridge, Singapore, Singapore
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32
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Parrish AB, Freel CD, Kornbluth S. Cellular mechanisms controlling caspase activation and function. Cold Spring Harb Perspect Biol 2013; 5:5/6/a008672. [PMID: 23732469 DOI: 10.1101/cshperspect.a008672] [Citation(s) in RCA: 410] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Caspases are the primary drivers of apoptotic cell death, cleaving cellular proteins that are critical for dismantling the dying cell. Initially translated as inactive zymogenic precursors, caspases are activated in response to a variety of cell death stimuli. In addition to factors required for their direct activation (e.g., dimerizing adaptor proteins in the case of initiator caspases that lie at the apex of apoptotic signaling cascades), caspases are regulated by a variety of cellular factors in a myriad of physiological and pathological settings. For example, caspases may be modified posttranslationally (e.g., by phosphorylation or ubiquitylation) or through interaction of modulatory factors with either the zymogenic or active form of a caspase, altering its activation and/or activity. These regulatory events may inhibit or enhance enzymatic activity or may affect activity toward particular cellular substrates. Finally, there is emerging literature to suggest that caspases can participate in a variety of cellular processes unrelated to apoptotic cell death. In these settings, it is particularly important that caspases are maintained under stringent control to avoid inadvertent cell death. It is likely that continued examination of these processes will reveal new mechanisms of caspase regulation with implications well beyond control of apoptotic cell death.
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Affiliation(s)
- Amanda B Parrish
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina 27710, USA
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Poly(ADP-ribose) polymerase is a substrate recognized by two metacaspases of Podospora anserina. EUKARYOTIC CELL 2013; 12:900-12. [PMID: 23584991 DOI: 10.1128/ec.00337-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The two metacaspases MCA1 and MCA2 of the fungal aging model organism Podospora anserina (PaMCA1 and PaMCA2, respectively) have previously been demonstrated to be involved in the control of programmed cell death (PCD) and life span. In order to identify specific pathways and components which are controlled by the activity of these enzymes, we set out to characterize them further. Heterologous overexpression in Escherichia coli of the two metacaspase genes resulted in the production of proteins which aggregate and form inclusion bodies from which the active protein has been recovered via refolding in appropriate buffers. The renaturated proteins are characterized by an arginine-specific activity and are active in caspase-like self-maturation leading to the generation of characteristic small protein fragments. Both activities are dependent on the presence of calcium. Incubation of the two metacaspases with recombinant poly(ADP-ribose) polymerase (PARP), a known substrate of mammalian caspases, led to the identification of PARP as a substrate of the two P. anserina proteases. Using double mutants in which P. anserina Parp (PaParp) is overexpressed and PaMca1 is either overexpressed or deleted, we provide evidence for in vivo degradation of PaPARP by PaMCA1. These results support the idea that the substrate profiles of caspases and metacaspases are at least partially overlapping. Moreover, they link PCD and DNA maintenance in the complex network of molecular pathways involved in aging and life span control.
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Elkoreh G, Blais V, Béliveau E, Guillemette G, Denault JB. Type 1 inositol-1,4,5-trisphosphate receptor is a late substrate of caspases during apoptosis. J Cell Biochem 2012; 113:2775-84. [PMID: 22473799 DOI: 10.1002/jcb.24155] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Apoptosis is characterized by the proteolytic cleavage of hundreds of proteins. One of them, the type 1 inositol-1,4,5-trisphosphate receptor (IP(3) R-1), a multimeric receptor located on the endoplasmic reticulum (ER) membrane that is critical to calcium homeostasis, was reported to be cleaved during staurosporine (STS) induced-apoptosis in Jurkat cells. Because the reported cleavage site separates the IP(3) binding site from the channel moiety, its cleavage would shut down a critical signaling pathway that is common to several cellular processes. Here we show that IP(3) R-1 is not cleaved in 293 cells treated with STS, TNFα, Trail, or ultra-violet (UV) irradiation. Further, it is not cleaved in Hela or Jurkat cells induced to undergo apoptosis with Trail, TNFα, or UV. In accordance with previous reports, we demonstrate that it is cleaved in a Jurkat cell line treated with STS. However its cleavage occurs only after poly(ADP-ribose) polymerase (PARP), which cleavage is a hallmark of apoptosis, and p23, a poor caspase-7 substrate, are completely cleaved, suggesting that IP(3) R-1 is a relatively late substrate of caspases. Nevertheless, the receptor is fully accessible to proteolysis in cellulo by ectopically overexpressed caspase-7 or by the tobacco etch virus (TEV) protease. Finally, using recombinant caspase-3 and microsomal fractions enriched in IP(3) R-1, we show that the receptor is a poor caspase-3 substrate. Consequently, we conclude that IP(3) R-1 is not a key death substrate.
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Affiliation(s)
- Ghadi Elkoreh
- Faculty of Medicine and Health Sciences, Department of Pharmacology, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke QC J1H 5N4, Canada
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35
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Cassidy SKB, Hagar JA, Kanneganti TD, Franchi L, Nuñez G, O'Riordan MXD. Membrane damage during Listeria monocytogenes infection triggers a caspase-7 dependent cytoprotective response. PLoS Pathog 2012; 8:e1002628. [PMID: 22807671 PMCID: PMC3395620 DOI: 10.1371/journal.ppat.1002628] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 02/22/2012] [Indexed: 11/24/2022] Open
Abstract
The cysteine protease caspase-7 has an established role in the execution of apoptotic cell death, but recent findings also suggest involvement of caspase-7 during the host response to microbial infection. Caspase-7 can be cleaved by the inflammatory caspase, caspase-1, and has been implicated in processing and activation of microbial virulence factors. Thus, caspase-7 function during microbial infection may be complex, and its role in infection and immunity has yet to be fully elucidated. Here we demonstrate that caspase-7 is cleaved during cytosolic infection with the intracellular bacterial pathogen, Listeria monocytogenes. Cleavage of caspase-7 during L. monocytogenes infection did not require caspase-1 or key adaptors of the primary pathways of innate immune signaling in this infection, ASC, RIP2 and MyD88. Caspase-7 protected infected macrophages against plasma membrane damage attributable to the bacterial pore-forming toxin Listeriolysin O (LLO). LLO-mediated membrane damage could itself trigger caspase-7 cleavage, independently of infection or overt cell death. We also detected caspase-7 cleavage upon treatment with other bacterial pore-forming toxins, but not in response to detergents. Taken together, our results support a model where cleavage of caspase-7 is a consequence of toxin-mediated membrane damage, a common occurrence during infection. We propose that host activation of caspase-7 in response to pore formation represents an adaptive mechanism by which host cells can protect membrane integrity during infection.
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Affiliation(s)
- Sara K. B. Cassidy
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Jon A. Hagar
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Thirumala Devi Kanneganti
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America
| | - Luigi Franchi
- Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Gabriel Nuñez
- Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Mary X. D. O'Riordan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
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Boucher D, Blais V, Denault JB. Caspase-7 uses an exosite to promote poly(ADP ribose) polymerase 1 proteolysis. Proc Natl Acad Sci U S A 2012; 109:5669-74. [PMID: 22451931 PMCID: PMC3326497 DOI: 10.1073/pnas.1200934109] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
During apoptosis, hundreds of proteins are cleaved by caspases, most of them by the executioner caspase-3. However, caspase-7, which shares the same substrate primary sequence preference as caspase-3, is better at cleaving poly(ADP ribose) polymerase 1 (PARP) and Hsp90 cochaperone p23, despite a lower intrinsic activity. Here, we identified key lysine residues (K(38)KKK) within the N-terminal domain of caspase-7 as critical elements for the efficient proteolysis of these two substrates. Caspase-7's N-terminal domain binds PARP and improves its cleavage by a chimeric caspase-3 by ∼30-fold. Cellular expression of caspase-7 lacking the critical lysine residues resulted in less-efficient PARP and p23 cleavage compared with cells expressing the wild-type peptidase. We further showed, using a series of caspase chimeras, the positioning of p23 on the enzyme providing us with a mechanistic insight into the binding of the exosite. In summary, we have uncovered a role for the N-terminal domain (NTD) and the N-terminal peptide of caspase-7 in promoting key substrate proteolysis.
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Affiliation(s)
- Dave Boucher
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada J1H 5N4
| | - Véronique Blais
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada J1H 5N4
| | - Jean-Bernard Denault
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada J1H 5N4
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37
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MacKenzie SH, Clark AC. Death by caspase dimerization. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 747:55-73. [PMID: 22949111 DOI: 10.1007/978-1-4614-3229-6_4] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Controlled cell death, or apoptosis, occurs in response to many different environmental stimuli. The apoptotic cascade that occurs within the cell in response to these cues leads to morphological and biochemical changes that trigger the dismantling and packaging of the cell. Caspases are a family of cysteine-dependent aspartate-directed proteases that play an integral role in the cascade that leads to apoptosis. Caspases are grouped as either initiators or effectors of apoptosis, depending on where they enter the cell death process. Prior to activation, initiator caspases are present as monomers that must dimerize for full activation whereas effector caspases are present as dimeric zymogens that must be processed for full activation. The stability of the dimer may be due predominately to the interactions in the dimer interface as each caspase has unique properties in this region that lend to its specific mode of activation. Moreover, dimerization is responsible for active site formation because both monomers contribute residues that enable the formation of a fully functional active site. Overall, dimerization plays a key role in the ability of caspases to form fully functional proteases.
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Affiliation(s)
- Sarah H MacKenzie
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA
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38
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Yakovlev AA, Gulyaeva NV. Pleiotropic functions of brain proteinases: Methodological considerations and search for caspase substrates. BIOCHEMISTRY (MOSCOW) 2011; 76:1079-86. [DOI: 10.1134/s0006297911100014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Intranasal delivery of caspase-9 inhibitor reduces caspase-6-dependent axon/neuron loss and improves neurological function after stroke. J Neurosci 2011; 31:8894-904. [PMID: 21677173 DOI: 10.1523/jneurosci.0698-11.2011] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Despite extensive research to develop an effective neuroprotective strategy for the treatment of ischemic stroke, therapeutic options remain limited. Although caspase-dependent death is thought to play a prominent role in neuronal injury, direct evidence of active initiator caspases in stroke and the functional relevance of this activity have not previously been shown. Using an unbiased caspase-trapping technique in vivo, we isolated active caspase-9 from ischemic rat brain within 1 h of reperfusion. Pathogenic relevance of active caspase-9 was shown by intranasal delivery of a novel cell membrane-penetrating highly specific inhibitor for active caspase-9 at 4 h postreperfusion (hpr). Caspase-9 inhibition provided neurofunctional protection and established caspase-6 as its downstream target. The temporal and spatial pattern of expression demonstrates that neuronal caspase-9 activity induces caspase-6 activation, mediating axonal loss by 12 hpr followed by neuronal death within 24 hpr. Collectively, these results support selective inhibition of these specific caspases as an effective therapeutic strategy for stroke.
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Abstract
During apoptosis, initiator caspases (8, 9 and 10) activate downstream executioner caspases (3, 6 and 7) by cleaving the IDC (interdomain connector) at two sites. Here, we demonstrate that both activation sites, site 1 and site 2, of caspase 7 are suboptimal for activation by initiator caspases 8 and 9 in cellulo, and in vitro using recombinant proteins and activation kinetics. Indeed, when both sites are replaced with the preferred motifs recognized by either caspase 8 or 9, we found an up to 36-fold improvement in activation. Moreover, cleavage at site 1 is preferred to site 2 because of its location within the IDC, since swapping sites does not lead to a more efficient activation. We also demonstrate the important role of Ile195 of site 1 involved in maintaining a network of contacts that preserves the proper conformation of the active enzyme. Finally, we show that the length of the IDC plays a crucial role in maintaining the necessity of proteolysis for activation. In fact, although we were unable to generate a caspase 7 that does not require proteolysis for activity, shortening the IDC of the initiator caspase 8 by four residues was sufficient to confer a requirement for proteolysis, a key feature of executioner caspases. Altogether, the results demonstrate the critical role of the primary structure of caspase 7's IDC for its activation and proteolytic activity.
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Affiliation(s)
| | | | - Marcin DRAG
- Division of Medicinal Chemistry and Microbiology, Faculty of Chemistry, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, POLAND
| | - Jean-Bernard DENAULT
- Corresponding author: Jean-Bernard Denault, Université de Sherbrooke, Faculty of medicine and health sciences, Pharmacology department, 3001, 12th Avenue North, Sherbrooke QC, J1H 5N4, CANADA, Phone: +1-819-820-6868 x12789, Fax: +1-819-564-5400,
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Caspase-8 and caspase-7 sequentially mediate proteolytic activation of acid sphingomyelinase in TNF-R1 receptosomes. EMBO J 2010; 30:379-94. [PMID: 21157428 DOI: 10.1038/emboj.2010.326] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Accepted: 11/16/2010] [Indexed: 01/02/2023] Open
Abstract
We previously demonstrated that tumour necrosis factor (TNF)-induced ceramide production by endosomal acid sphingomyelinase (A-SMase) couples to apoptosis signalling via activation of cathepsin D and cleavage of Bid, resulting in caspase-9 and caspase-3 activation. The mechanism of TNF-mediated A-SMase activation within the endolysosomal compartment is poorly defined. Here, we show that TNF-induced A-SMase activation depends on functional caspase-8 and caspase-7 expression. The active forms of all three enzymes, caspase-8, caspase-7 and A-SMase, but not caspase-3, colocalize in internalized TNF receptosomes. While caspase-8 and caspase-3 are unable to induce activation of purified pro-A-SMase, we found that caspase-7 mediates A-SMase activation by direct interaction resulting in proteolytic cleavage of the 72-kDa pro-A-SMase zymogen at the non-canonical cleavage site after aspartate 253, generating an active 57 kDa A-SMase molecule. Caspase-7 down modulation revealed the functional link between caspase-7 and A-SMase, confirming proteolytic cleavage as one further mode of A-SMase activation. Our data suggest a signalling cascade within TNF receptosomes involving sequential activation of caspase-8 and caspase-7 for induction of A-SMase activation by proteolytic cleavage of pro-A-SMase.
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Role of cellular caspases, nuclear factor-kappa B and interferon regulatory factors in Bluetongue virus infection and cell fate. Virol J 2010; 7:362. [PMID: 21134281 PMCID: PMC3002312 DOI: 10.1186/1743-422x-7-362] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Accepted: 12/06/2010] [Indexed: 01/14/2023] Open
Abstract
Background Bluetongue virus (BTV) infection causes haemorrhagic disease in ruminants and induces cell death. The pathogenesis in animals and in cell culture has been linked to BTV-induced apoptosis. Results In this report, we investigated BTV-induced apoptosis in cell culture in depth and show that both extrinsic (caspase-8 activation) and intrinsic (caspase-9 activation) pathways play roles in BTV apoptosis. Further, by using chemical inhibitors and knock-out cell lines, we show that these pathways act independently of each other in BTV infected cells. In addition to activation of caspase-8, -9 and executioner caspase-3, we also identified that BTV infection causes the activation of caspase-7, which results in the cleavage of poly (ADP-ribose) polymerase (PARP). BTV-induced cell death appears to be due to apoptosis rather than necrosis, as the HMBG-1 was not translocated from the nucleus. We also examined if NF-κB response is related to BTV-induced apoptosis as in reovirus. Our data suggests that NF-κB response is not linked to the induction of apoptosis. It is controlled by the degradation of only IκBα but not IκBβ, resulting in a rapid transient response during BTV infection. This was supported using an NF-κB dependent luciferase reporter gene assay, which demonstrated early response, that appeared to be suppressed by the late stage of BTV replication. Furthermore, virus titres were higher in the presence of NF-κB inhibitor (SN50), indicating that NF-κB has a role in initiating an antiviral environment. In addition, we show that BTV infection induces the translocation of interferon regulatory factors (IRF-3 and IRF-7) into the nucleus. The induction of IRF responses, when measured by IRF dependent luciferase reporter gene assay, revealed that the IRF responses, like NF-κB response, were also at early stage of infection and mirrored the timing of NF-κB induction. Conclusion BTV triggers a wide range of caspase activities resulting in cell apoptosis. Although both NF-κB and IRF responses are induced by BTV infection, they are not sustained.
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Substrate-induced conformational changes occur in all cleaved forms of caspase-6. J Mol Biol 2010; 406:75-91. [PMID: 21111746 DOI: 10.1016/j.jmb.2010.11.031] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2010] [Revised: 11/16/2010] [Accepted: 11/16/2010] [Indexed: 11/23/2022]
Abstract
Caspase-6 is an apoptotic cysteine protease that also governs disease progression in Huntington's and Alzheimer's diseases. Caspase-6 is of great interest as a target for treatment of these neurodegenerative diseases; however, the molecular basis of caspase-6 function and regulation remains poorly understood. In the recently reported structure of caspase-6, the 60's and 130's helices at the base of the substrate-binding groove extend upward, in a conformation entirely different from that of any other caspase. Presently, the central question about caspase-6 structure and function is whether the extended conformation is the catalytically competent conformation or whether the extended helices must undergo a large conformational rearrangement in order to bind substrate. We have generated a series of caspase-6 cleavage variants, including a novel constitutively two-chain form, and determined crystal structures of caspase-6 with and without the intersubunit linker. This series allows evaluation of the role of the prodomain and intersubunit linker on caspase-6 structure and function before and after substrate binding. Caspase-6 is inherently more stable than closely related caspases. Cleaved caspase-6 with both the prodomain and the linker present is the most stable, indicating that these two regions act in concert to increase stability, but maintain the extended conformation in the unliganded state. Moreover, these data suggest that caspase-6 undergoes a significant conformational change upon substrate binding, adopting a structure that is more like canonical caspases.
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44
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Wang XJ, Cao Q, Liu X, Wang KT, Mi W, Zhang Y, Li LF, LeBlanc AC, Su XD. Crystal structures of human caspase 6 reveal a new mechanism for intramolecular cleavage self-activation. EMBO Rep 2010; 11:841-7. [PMID: 20890311 DOI: 10.1038/embor.2010.141] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Revised: 08/12/2010] [Accepted: 08/17/2010] [Indexed: 11/09/2022] Open
Abstract
Dimeric effectors caspase 3 and caspase 7 are activated by initiator caspase processing. In this study, we report the crystal structures of effector caspase 6 (CASP6) zymogen and N-Acetyl-Val-Glu-Ile-Asp-al-inhibited CASP6. Both of these forms of CASP6 have a dimeric structure, and in CASP6 zymogen the intersubunit cleavage site (190)TEVD(193) is well structured and inserts into the active site. This positions residue Asp 193 to be easily attacked by the catalytic residue Cys 163. We demonstrate biochemically that intramolecular cleavage at Asp 193 is a prerequisite for CASP6 self-activation and that this activation mechanism is dependent on the length of the L2 loop. Our results indicate that CASP6 can be activated and regulated through intramolecular self-cleavage.
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Affiliation(s)
- Xiao-Jun Wang
- National Laboratory of Protein Engineering & Plant Genetic Engineering, Peking University, Haidian District, Beijing, People's Republic of China
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45
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Oberst A, Pop C, Tremblay AG, Blais V, Denault JB, Salvesen GS, Green DR. Inducible dimerization and inducible cleavage reveal a requirement for both processes in caspase-8 activation. J Biol Chem 2010; 285:16632-42. [PMID: 20308068 DOI: 10.1074/jbc.m109.095083] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Caspase-8 is a cysteine protease activated by membrane-bound receptors at the cytosolic face of the cell membrane, initiating the extrinsic pathway of apoptosis. Caspase-8 activation relies on recruitment of inactive monomeric zymogens to activated receptor complexes, where they produce a fully active enzyme composed of two catalytic domains. Although in vitro studies using drug-mediated affinity systems or kosmotropic salts to drive dimerization have indicated that uncleaved caspase-8 can be readily activated by dimerization alone, in vivo results using mouse models have reached the opposite conclusion. Furthermore, in addition to interdomain autoprocessing, caspase-8 can be cleaved by activated executioner caspases, and reports of whether this cleavage event can lead to activation of caspase-8 have been conflicting. Here, we address these questions by carrying out studies of the activation characteristics of caspase-8 mutants bearing prohibitive mutations at the interdomain cleavage sites both in vitro and in cell lines lacking endogenous caspase-8, and we find that elimination of these cleavage sites precludes caspase-8 activation by prodomain-driven dimerization. We then further explore the consequences of interdomain cleavage of caspase-8 by adapting the tobacco etch virus protease to create a system in which both the cleavage and the dimerization of caspase-8 can be independently controlled in living cells. We find that unlike the executioner caspases, which are readily activated by interdomain cleavage alone, neither dimerization nor cleavage of caspase-8 alone is sufficient to activate caspase-8 or induce apoptosis and that only the coordinated dimerization and cleavage of the zymogen produce efficient activation in vitro and apoptosis in cellular systems.
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Affiliation(s)
- Andrew Oberst
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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46
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Amer AO. Modulation of caspases and their non-apoptotic functions byLegionella pneumophila. Cell Microbiol 2010; 12:140-7. [DOI: 10.1111/j.1462-5822.2009.01401.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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47
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Agniswamy J, Fang B, Weber IT. Conformational similarity in the activation of caspase-3 and -7 revealed by the unliganded and inhibited structures of caspase-7. Apoptosis 2010; 14:1135-44. [PMID: 19655253 DOI: 10.1007/s10495-009-0388-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Caspase-mediated apoptosis has important roles in normal cell differentiation and aging and in many diseases including cancer, neuromuscular disorders and neurodegenerative diseases. Therefore, modulation of caspase activity and conformational states is of therapeutic importance. We report crystal structures of a new unliganded conformation of caspase-7 and the inhibited caspase-7 with the tetrapeptide Ac-YVAD-Cho. Different conformational states and mechanisms for substrate recognition have been proposed based on unliganded structures of the redundant apoptotic executioner caspase-3 and -7. The current study shows that the executioner caspase-3 and -7 have similar conformations for the unliganded active site as well as the inhibitor-bound active site. The new unliganded caspase-7 structure exhibits the tyrosine flipping mechanism in which the Tyr230 has rotated to block entry to the S2 binding site similar to the active site conformation of unliganded caspase-3. The inhibited structure of caspase-7/YVAD shows that the P4 Tyr binds the S4 region specific to polar residues at the expense of a main chain hydrogen bond between the P4 amide and carbonyl oxygen of caspase-7 Gln 276, which is similar to the caspase-3 complex. This new knowledge of the structures and conformational states of unliganded and inhibited caspases will be important for the design of drugs to modulate caspase activity and apoptosis.
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Affiliation(s)
- Johnson Agniswamy
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA
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48
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Lamkanfi M, Kanneganti TD. Caspase-7: a protease involved in apoptosis and inflammation. Int J Biochem Cell Biol 2009; 42:21-4. [PMID: 19782763 DOI: 10.1016/j.biocel.2009.09.013] [Citation(s) in RCA: 190] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 09/18/2009] [Accepted: 09/20/2009] [Indexed: 01/27/2023]
Abstract
Caspase-7 was considered to be redundant with caspase-3 because these related cysteine proteases share an optimal peptide recognition sequence and have several endogenous protein substrates in common. In addition, both caspases are proteolytically activated by the initiator caspase-8 and -9 during death receptor- and DNA-damage-induced apoptosis, respectively. However, a growing body of biochemical and physiological data indicate that caspase-7 also differs in significant ways from caspase-3. For instance, several substrates are specifically cleaved by caspase-7, but not caspase-3. Moreover, caspase-7 activation requires caspase-1 inflammasomes under inflammatory conditions, while caspase-3 processing proceeds independently of caspase-1. Finally, caspase-7 deficient mice are resistant to endotoxemia, whereas caspase-3 knockout mice are susceptible. These findings suggest that specifically interfering with caspase-7 activation may hold therapeutic value for the treatment of cancer and inflammatory ailments.
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Affiliation(s)
- Mohamed Lamkanfi
- Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium; Department of Medical Protein Research, VIB, B-9000 Ghent, Belgium
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Witkowski WA, Hardy JA. L2' loop is critical for caspase-7 active site formation. Protein Sci 2009; 18:1459-68. [PMID: 19530232 DOI: 10.1002/pro.151] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The active sites of caspases are composed of four mobile loops. A loop (L2) from one half of the dimer interacts with a loop (L2') from the other half of the dimer to bind substrate. In an inactive form, the two L2' loops form a cross-dimer hydrogen-bond network over the dimer interface. Although the L2' loop has been implicated as playing a central role in the formation of the active-site loop bundle, its precise role in catalysis has not been shown. A detailed understanding of the active and inactive conformations is essential to control the caspase function. We have interrogated the contributions of the residues in the L2' loop to catalytic function and enzyme stability. In wild-type and all mutants, active-site binding results in substantial stabilization of the complex. One mutation, P214A, is significantly destabilized in the ligand-free conformation, but is as stable as wild type when bound to substrate, indicating that caspase-7 rests in different conformations in the absence and presence of substrate. Residues K212 and I213 in the L2' loop are shown to be essential for substrate-binding and thus proper catalytic function of the caspase. In the crystal structure of I213A, the void created by side-chain deletion is compensated for by rearrangement of tyrosine 211 to fill the void, suggesting that the requirements of substrate-binding are sufficiently strong to induce the active conformation. Thus, although the L2' loop makes no direct contacts with substrate, it is essential for buttressing the substrate-binding groove and is central to native catalytic efficiency.
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Affiliation(s)
- Witold A Witkowski
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA
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50
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Gafni J, Cong X, Chen SF, Gibson BW, Ellerby LM. Calpain-1 cleaves and activates caspase-7. J Biol Chem 2009; 284:25441-9. [PMID: 19617626 DOI: 10.1074/jbc.m109.038174] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Caspase-7 is an executioner caspase that plays a key role in apoptosis, cancer, and a number of neurodegenerative diseases. The mechanism of caspase-7 activation by granzyme B and caspase-3 has been well characterized. However, whether other proteases such as calpains activate or inactivate caspase-7 is not known. Here, we present that recombinant caspase-7 is directly cleaved by calpain-1 within the large subunit of caspase-7 to produce two novel products, large subunit p18 and p17. This new form of caspase-7 has a 6-fold increase in V(max) when compared with the previously characterized p20/p12 form. Zymography revealed that the smaller caspase-7 product (p17) is 18-fold more active than either the caspase-3-cleaved product (p20) or the larger calpain-1 product of caspase-7 (p18). Mass spectrometry and site-directed mutagenesis identified the calpain cleavage sites within the caspase-7 large subunit at amino acid 36 and 45/47. These proteolysis events occur in vivo as indicated by the accumulation of caspase-7 p18 and p17 subunits in cortical neurons undergoing Ca(2+) dysregulation. Further, cleavage at amino acid 45/47 of caspase-7 by calpain results in a reduction in nuclear localization when compared with the caspase-3 cleavage product of caspase-7 (p20). Our studies suggest the calpain-activated form of caspase-7 has unique enzymatic activity, localization, and binding affinity when compared with the caspase-activated form.
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Affiliation(s)
- Juliette Gafni
- Buck Institute for Age Research, Novato, California 94945, USA
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