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Yang B, Yao H, Li D, Liu Z. The phosphatidylglycerol phosphate synthase PgsA utilizes a trifurcated amphipathic cavity for catalysis at the membrane-cytosol interface. Curr Res Struct Biol 2021; 3:312-323. [PMID: 34901881 PMCID: PMC8640168 DOI: 10.1016/j.crstbi.2021.11.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 10/24/2021] [Accepted: 11/17/2021] [Indexed: 12/26/2022] Open
Abstract
Phosphatidylglycerol is a crucial phospholipid found ubiquitously in biological membranes of prokaryotic and eukaryotic cells. The phosphatidylglycerol phosphate (PGP) synthase (PgsA), a membrane-embedded enzyme, catalyzes the primary reaction of phosphatidylglycerol biosynthesis. Mutations in pgsA frequently correlate with daptomycin resistance in Staphylococcus aureus and other prevalent infectious pathogens. Here we report the crystal structures of S. aureus PgsA (SaPgsA) captured at two distinct states of the catalytic process, with lipid substrate (cytidine diphosphate-diacylglycerol, CDP-DAG) or product (PGP) bound to the active site within a trifurcated amphipathic cavity. The hydrophilic head groups of CDP-DAG and PGP occupy two different pockets in the cavity, inducing local conformational changes. An elongated membrane-exposed surface groove accommodates the fatty acyl chains of CDP-DAG/PGP and opens a lateral portal for lipid entry/release. Remarkably, the daptomycin resistance-related mutations mostly cluster around the active site, causing reduction of enzymatic activity. Our results provide detailed mechanistic insights into the dynamic catalytic process of PgsA and structural frameworks beneficial for development of antimicrobial agents targeting PgsA from pathogenic bacteria. PgsA uses a trifurcated amphipathic cavity for binding of substrates or products. Conversion of CDP-DAG to PGP induces local conformational changes in PgsA. Daptomycin-resistant mutations of PgsA mostly lead to reduced catalytic activity. A structure-based five-state model is proposed for the synthesis of PGP by PgsA.
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Affiliation(s)
- Bowei Yang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hebang Yao
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, 201210, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Dianfan Li
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, 201210, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhenfeng Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
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Wang Z, Fu W, Huo M, He B, Liu Y, Tian L, Li W, Zhou Z, Wang B, Xia J, Chen Y, Wei J, Abliz Z. Spatial-resolved metabolomics reveals tissue-specific metabolic reprogramming in diabetic nephropathy by using mass spectrometry imaging. Acta Pharm Sin B 2021; 11:3665-77. [PMID: 34900545 DOI: 10.1016/j.apsb.2021.05.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/26/2021] [Accepted: 05/05/2021] [Indexed: 12/22/2022] Open
Abstract
Detailed knowledge on tissue-specific metabolic reprogramming in diabetic nephropathy (DN) is vital for more accurate understanding the molecular pathological signature and developing novel therapeutic strategies. In the present study, a spatial-resolved metabolomics approach based on air flow-assisted desorption electrospray ionization (AFADESI) and matrix-assisted laser desorption ionization (MALDI) integrated mass spectrometry imaging (MSI) was proposed to investigate tissue-specific metabolic alterations in the kidneys of high-fat diet-fed and streptozotocin (STZ)-treated DN rats and the therapeutic effect of astragaloside IV, a potential anti-diabetic drug, against DN. As a result, a wide range of functional metabolites including sugars, amino acids, nucleotides and their derivatives, fatty acids, phospholipids, sphingolipids, glycerides, carnitine and its derivatives, vitamins, peptides, and metal ions associated with DN were identified and their unique distribution patterns in the rat kidney were visualized with high chemical specificity and high spatial resolution. These region-specific metabolic disturbances were ameliorated by repeated oral administration of astragaloside IV (100 mg/kg) for 12 weeks. This study provided more comprehensive and detailed information about the tissue-specific metabolic reprogramming and molecular pathological signature in the kidney of diabetic rats. These findings highlighted the promising potential of AFADESI and MALDI integrated MSI based metabolomics approach for application in metabolic kidney diseases.
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Key Words
- ADP, adenosine diphosphate
- AFADESI, air flow-assisted desorption electrospray ionization
- AGEs, advanced glycation end products
- AMP, adenosine monophosphate
- AMPK, adenosine monophosphate activated protein kinase
- AST, astragaloside IV
- ATP, adenosine triphosphate
- Astragaloside IV
- BUN, blood urea nitrogen
- CL, cardiolipin
- Cre, creatinine
- DAG, diacylglycerol
- DESI, desorption electrospray ionization
- DM, diabetes mellitus
- DN, diabetic nephropathy
- DPA, docosapentaenoic acid
- Diabetic nephropathy
- ESKD, end-stage kidney disease
- FBG, fasting blood glucose
- GLU, glucose
- GMP, guanosine monophosphate
- GSH, glutathione
- H&E, hematoxylin and eosin
- HPLC, high-performance liquid chromatography
- HbA1c, glycosylated hemoglobin
- LysoPC, lysophosphatidylcholine
- LysoPG, lysophosphatidylglycerol
- MALDI, matrix-assisted laser desorption ionization
- MS, mass spectrometry
- MSI, mass spectrometry imaging
- Mass spectrometry imaging
- Metabolic reprogramming
- NMR, nuclear magnetic resonance
- Na-CMC, sodium carboxymethyl cellulose
- PA, phosphatidic acid
- PC, phosphatidylcholine
- PE, phosphatidylethanolamine
- PG, phosphatidylglycerol
- PPP, pentose phosphate pathway
- PS, phosphatidylserine
- PUFA, polyunsaturated fatty acids
- ROI, regions of interest
- ROS, reactive oxygen species
- SDH, succinate dehydrogenase
- SGLTs, sodium-glucose cotransporters
- SM, sphingomyelin
- STZ, streptozotocin
- Spatial-resolved metabolomics
- TCA, tricarboxylic acid
- TCHO, total cholesterol
- TG, triglyceride
- UMP, uridine monophosphate
- VIP, variable importance in projection
- p-AMPK, phosphorylated adenosine monophosphate activated protein kinase
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Abstract
Mitochondria are functionally versatile organelles. In addition to their conventional role of meeting the cell's energy requirements, mitochondria also actively regulate innate immune responses against infectious and sterile insults. Components of mitochondria, when released or exposed in response to dysfunction or damage, can be directly recognized by receptors of the innate immune system and trigger an immune response. In addition, despite initiation that may be independent from mitochondria, numerous innate immune responses are still subject to mitochondrial regulation as discrete steps of their signaling cascades occur on mitochondria or require mitochondrial components. Finally, mitochondrial metabolites and the metabolic state of the mitochondria within an innate immune cell modulate the precise immune response and shape the direction and character of that cell's response to stimuli. Together, these pathways result in a nuanced and very specific regulation of innate immune responses by mitochondria.
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Key Words
- ASC, Apoptosis Associated Speck like protein containing CARD
- ASK1, apoptosis signal-regulating kinase 1
- ATP, adenosine tri-phosphate
- CAPS, cryopyrin associated periodic syndromes
- CARD, caspase activation and recruitment domain
- CL, cardiolipin
- CLR, C-type lectin receptor
- CREB, cAMP response element binding protein
- Cgas, cyclic GMP-AMP synthase
- DAMP, damage associated molecular pattern
- ESCIT, evolutionarily conserved signaling intermediate in the toll pathway
- ETC, electron transport chain
- FPR, formyl peptide receptor
- HIF, hypoxia-inducible factor
- HMGB1, high mobility group box protein 1
- IFN, interferon
- IL, interleukin
- IRF, interferon regulatory factor
- JNK, cJUN NH2-terminal kinase
- LPS, lipopolysaccharide
- LRR, leucine rich repeat
- MAPK, mitogen-activated protein kinase
- MARCH5, membrane-associated ring finger (C3HC4) 5
- MAVS, mitochondrial antiviral signaling
- MAVS, mitochondrial antiviral signaling protein
- MFN1/2, mitofusin
- MOMP, mitochondrial outer membrane permeabilization
- MPT, mitochondrial permeability transition
- MyD88, myeloid differentiation primary response 88
- NADH, nicotinamide adenine dinucleotide
- NBD, nucleotide binding domain
- NFκB, Nuclear factor κ B
- NLR, NOD like receptor
- NOD, nucleotide-binding oligomerization domain
- NRF2, nuclear factor erythroid 2-related factor 2
- PAMP, pathogen associated molecular pattern
- PPAR, peroxisome proliferator-accelerated receptor
- PRRs, pathogen recognition receptors
- RIG-I, retinoic acid inducible gene I
- RLR, retinoic acid inducible gene like receptor
- ROS, reactive oxygen species
- STING, stimulator of interferon gene
- TAK1, transforming growth factor-β-activated kinase 1
- TANK, TRAF family member-associated NFκB activator
- TBK1, TANK Binding Kinase 1
- TCA, Tri-carboxylic acid
- TFAM, mitochondrial transcription factor A
- TLR, Toll Like Receptor
- TRAF6, tumor necrosis factor receptor-associated factor 6
- TRIF, TIR-domain-containing adapter-inducing interferon β
- TUFM, Tu translation elongation factor.
- fMet, N-formylated methionine
- mROS, mitochondrial ROS
- mtDNA, mitochondrial DNA
- n-fp, n-formyl peptides
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Abstract
Mitochondria are functionally versatile organelles. In addition to their conventional role of meeting the cell's energy requirements, mitochondria also actively regulate innate immune responses against infectious and sterile insults. Components of mitochondria, when released or exposed in response to dysfunction or damage, can be directly recognized by receptors of the innate immune system and trigger an immune response. In addition, despite initiation that may be independent from mitochondria, numerous innate immune responses are still subject to mitochondrial regulation as discrete steps of their signaling cascades occur on mitochondria or require mitochondrial components. Finally, mitochondrial metabolites and the metabolic state of the mitochondria within an innate immune cell modulate the precise immune response and shape the direction and character of that cell's response to stimuli. Together, these pathways result in a nuanced and very specific regulation of innate immune responses by mitochondria.
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Key Words
- ASC, Apoptosis Associated Speck like protein containing CARD
- ASK1, apoptosis signal-regulating kinase 1
- ATP, adenosine tri-phosphate
- CAPS, cryopyrin associated periodic syndromes
- CARD, caspase activation and recruitment domain
- CL, cardiolipin
- CLR, C-type lectin receptor
- CREB, cAMP response element binding protein
- Cgas, cyclic GMP-AMP synthase
- DAMP, damage associated molecular pattern
- ESCIT, evolutionarily conserved signaling intermediate in the toll pathway
- ETC, electron transport chain
- FPR, formyl peptide receptor
- HIF, hypoxia-inducible factor
- HMGB1, high mobility group box protein 1
- IFN, interferon
- IL, interleukin
- IRF, interferon regulatory factor
- JNK, cJUN NH2-terminal kinase
- LPS, lipopolysaccharide
- LRR, leucine rich repeat
- MAPK, mitogen-activated protein kinase
- MARCH5, membrane-associated ring finger (C3HC4) 5
- MAVS, mitochondrial antiviral signaling
- MAVS, mitochondrial antiviral signaling protein
- MFN1/2, mitofusin
- MOMP, mitochondrial outer membrane permeabilization
- MPT, mitochondrial permeability transition
- MyD88, myeloid differentiation primary response 88
- NADH, nicotinamide adenine dinucleotide
- NBD, nucleotide binding domain
- NFκB, Nuclear factor κ B
- NLR, NOD like receptor
- NOD, nucleotide-binding oligomerization domain
- NRF2, nuclear factor erythroid 2-related factor 2
- PAMP, pathogen associated molecular pattern
- PPAR, peroxisome proliferator-accelerated receptor
- PRRs, pathogen recognition receptors
- RIG-I, retinoic acid inducible gene I
- RLR, retinoic acid inducible gene like receptor
- ROS, reactive oxygen species
- STING, stimulator of interferon gene
- TAK1, transforming growth factor-β-activated kinase 1
- TANK, TRAF family member-associated NFκB activator
- TBK1, TANK Binding Kinase 1
- TCA, Tri-carboxylic acid
- TFAM, mitochondrial transcription factor A
- TLR, Toll Like Receptor
- TRAF6, tumor necrosis factor receptor-associated factor 6
- TRIF, TIR-domain-containing adapter-inducing interferon β
- TUFM, Tu translation elongation factor.
- fMet, N-formylated methionine
- mROS, mitochondrial ROS
- mtDNA, mitochondrial DNA
- n-fp, n-formyl peptides
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Affiliation(s)
- Balaji Banoth
- Women's Guild Lung Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California
| | - Suzanne L Cassel
- Women's Guild Lung Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California.
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Watanabe Y, Kobayashi I, Ohnaka T, Watanabe S. In vitro synthesis of phospholipids with yeast phospholipase B, a phospholipid deacylating enzyme. ACTA ACUST UNITED AC 2018; 18:e00250. [PMID: 29876301 PMCID: PMC5989593 DOI: 10.1016/j.btre.2018.e00250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 03/19/2018] [Accepted: 03/28/2018] [Indexed: 11/30/2022]
Abstract
Saccharomyces cerevisiae PLB enzyme was expressed in E. coli. Purified Scplb1p exhibited deacylation activity. Purified Scplb1p transacylated LPC to PC and esterified LPC with FFA.
The gene encoding the Saccharomyces cerevisiae phospholipid deacylation enzyme, phospholipase B (ScPLB1), was successfully expressed in E. coli. The enzyme (Scplb1p) was engineered to have a histidine-tag at the C-terminal end and was purified by metal (Ni) affinity chromatography. Enzymatic properties, optimal pH, and substrate specificity were similar to those reported previously. For example, deacylation activity was observed in acidic pH in the absence of Ca2+ and was additive in neutral pH in the presence of Ca2+, and the enzyme had the same substrate priority as reported previously, with the exception of PE, suggesting that yeast phospholipase B could be produced in its native structure in bacterial cells. Scplb1p retained transacylation activity in aqueous medium, and esterified lysophosphatidylcholine with free fatty acid to form phosphatidylcholine in a non-aqueous, glycerin medium. We propose that phospholipase B could serve as an additional tool for in vitro enzyme-mediated phospholipid synthesis.
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Key Words
- CL, cardiolipin
- DHA, docosahexaenoic acid
- EDTA, ethylenediaminetetraacetic acid
- ELSD, evaporated light scattering detector
- Enzyme-mediated phospholipid synthesis
- Esterification
- FFA, free fatty acid
- HPLC, high-pressure liquid chromatography
- LPC, lysophosphatidylcholine
- PA, phosphatidic acid
- PC, phosphatidylcholine
- PE, phosphatidylethanolamine
- PI, phosphatidylinositol
- PLA2, phospholipase A2
- PLB, phospholipase B
- PS, phosphatidylserine
- Phospholipid deacylating enzyme
- Saccharomyces cerevisiae phospholipase B
- Transacylation
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Affiliation(s)
- Yasuo Watanabe
- Department of Bioscience, Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime, 790-8566, Japan
| | - Itsuki Kobayashi
- Department of Bioscience, Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime, 790-8566, Japan
| | - Takanori Ohnaka
- Department of Bioscience, Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime, 790-8566, Japan
| | - Seiya Watanabe
- Department of Bioscience, Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime, 790-8566, Japan
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Abstract
Tafazzin (TAZ) is a phospholipid transacylase that catalyzes the remodeling of cardiolipin, a mitochondrial phospholipid required for oxidative phosphorylation. Mutations of TAZ cause Barth syndrome, which is characterized by mitochondrial dysfunction and dilated cardiomyopathy, leading to premature death. However, the molecular mechanisms underlying the cause of mitochondrial dysfunction in Barth syndrome remain poorly understood. Here we investigated the role of TAZ in regulating mitochondrial function and mitophagy. Using primary mouse embryonic fibroblasts (MEFs) with doxycycline-inducible knockdown of Taz, we showed that TAZ deficiency in MEFs caused defective mitophagosome biogenesis, but not other autophagic processes. Consistent with a key role of mitophagy in mitochondria quality control, TAZ deficiency in MEFs also led to impaired oxidative phosphorylation and severe oxidative stress. Together, these findings provide key insights on mitochondrial dysfunction in Barth syndrome, suggesting that pharmacological restoration of mitophagy may provide a novel treatment for this lethal condition.
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Key Words
- AdGFP-LC3, recombinant adenovirus expressing GFP tagged MAP1LC3B
- AdTAZ, recombinant adenovirus expressing Myc-tagged TAZ
- BTHS, Barth syndrome
- BafA1, bafilomycin A1
- Barth syndrome
- CCCP, carbonyl cyanide m-chlorophenylhydrazone
- CL, cardiolipin
- Dox, doxycycline
- FCCP, carbonyl cyanide p-triflouromethoxyphenylhydrazone
- LTG, LysoTracker Green
- MAP1LC3B/LC3B, microtubule-associated protein 1 light chain 3 beta
- MEF, mouse embryonic fibroblast
- MLCL, monolysocardiolipin
- MTR, MitoTracker Red
- PARK2, parkin RBR E3 ubiquitin protein ligase
- PINK1, PTEN-induced putative kinase 1
- SOD2, superoxide dismutase 2 mitochondrial
- TAZ, tafazzin
- TLCL, tetralinoleoyl-cardiolipin
- autophagy
- cardiolipin
- mitochondrial dysfunction
- mitophagosome
- mitophagy
- tafazzin
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Affiliation(s)
- Paul Hsu
- a Department of Cellular and Molecular Physiology ; Hershey , PA USA
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Suga K, Hamasaki A, Chinzaka J, Umakoshi H. Liposomes modified with cardiolipin can act as a platform to regulate the potential flux of NADP +-dependent isocitrate dehydrogenase. Metab Eng Commun 2016; 3:8-14. [PMID: 29142819 DOI: 10.1016/j.meteno.2015.11.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Revised: 11/05/2015] [Accepted: 11/10/2015] [Indexed: 11/22/2022] Open
Abstract
Cardiolipin (CL) is a phospholipid found in the outer mitochondrial membrane (OMM) and inner mitochondrial membrane (IMM) in animal cells. Isocitrate dehydrogenase (ICDH) is an important catalytic enzyme that is localized at the cytosol and mitochondria; the metabolic pathway catalyzed by ICDH differs between the OMM and IMM. To estimate the possible role of lipid membrane in the enzymatic activity of NADP+-dependent ICDH, CL-modified liposomes were prepared using CL/1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)/cholesterol (Ch), and their characteristics were analyzed based on the fluorescent probe method. The relative enzymatic activity of ICDH decreased in the presence of CL/DPPC/Ch=(30/50/20) liposome, whereas activity increased in the presence of CL/DPPC/Ch=(5/75/20) liposome. NADP+ had the greatest substrate affinity and was dominant in the regulation of ICDH activity. Analysis of membrane properties indicated that membranes in CL-modified liposomes were dehydrated by ICDH binding. Using circular dichroism analysis, CL/DPPC/Ch=(30/50/20) liposome induced a conformational change in ICDH, indicating that CL-rich membrane domains could inhibit ICDH activity. These results suggest that lipid membranes, including CL molecules, could act as a platform to regulate ICDH-related metabolic pathways such as the tricarboxylic acid cycle and lipid synthesis. Phosphatidylcholine liposomes were modified with cardiolipin and characterized. DPPC liposomes did not affect the activity of ICDH. ICDH activity was enhanced with liposomes at 5 mol% cardiolipin. ICDH activity was lowered with liposomes at 30 mol% cardiolipin. Liposomes with high content of cardiolipin led to conformational changes of ICDH.
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Key Words
- CL, cardiolipin
- Cardiolipin
- Ch, cholesterol
- DPPC, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine
- ICDH, isocitrate dehydrogenase
- IMM, inner mitochondrial membrane
- Isocitrate dehydrogenase
- LUV, large unilamellar vesicles
- Liposome
- MLV, multilamellar vesicles
- Membranome
- NADP+, β-nicotinamide-adenine dinucleotide phosphate oxidized form
- NADPH, β-nicotinamide-adenine dinucleotide phosphate reduced form
- OMM, outer mitochondrial membrane
- PDB, protein data bank
- System biology
- TCA, tricarboxylic acid
- ld, liquid-disordered
- lo, liquid-ordered
- so, solid-ordered
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Richard VR, Beach A, Piano A, Leonov A, Feldman R, Burstein MT, Kyryakov P, Gomez-Perez A, Arlia-Ciommo A, Baptista S, Campbell C, Goncharov D, Pannu S, Patrinos D, Sadri B, Svistkova V, Victor A, Titorenko VI. Mechanism of liponecrosis, a distinct mode of programmed cell death. Cell Cycle 2015; 13:3707-26. [PMID: 25483081 DOI: 10.4161/15384101.2014.965003] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
An exposure of the yeast Saccharomyces cerevisiae to exogenous palmitoleic acid (POA) elicits "liponecrosis," a mode of programmed cell death (PCD) which differs from the currently known PCD subroutines. Here, we report the following mechanism for liponecrotic PCD. Exogenously added POA is incorporated into POA-containing phospholipids that then amass in the endoplasmic reticulum membrane, mitochondrial membranes and the plasma membrane. The buildup of the POA-containing phospholipids in the plasma membrane reduces the level of phosphatidylethanolamine in its extracellular leaflet, thereby increasing plasma membrane permeability for small molecules and committing yeast to liponecrotic PCD. The excessive accumulation of POA-containing phospholipids in mitochondrial membranes impairs mitochondrial functionality and causes the excessive production of reactive oxygen species in mitochondria. The resulting rise in cellular reactive oxygen species above a critical level contributes to the commitment of yeast to liponecrotic PCD by: (1) oxidatively damaging numerous cellular organelles, thereby triggering their massive macroautophagic degradation; and (2) oxidatively damaging various cellular proteins, thus impairing cellular proteostasis. Several cellular processes in yeast exposed to POA can protect cells from liponecrosis. They include: (1) POA oxidation in peroxisomes, which reduces the flow of POA into phospholipid synthesis pathways; (2) POA incorporation into neutral lipids, which prevents the excessive accumulation of POA-containing phospholipids in cellular membranes; (3) mitophagy, a selective macroautophagic degradation of dysfunctional mitochondria, which sustains a population of functional mitochondria needed for POA incorporation into neutral lipids; and (4) a degradation of damaged, dysfunctional and aggregated cytosolic proteins, which enables the maintenance of cellular proteostasis.
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Key Words
- CFU, colony forming units
- CL, cardiolipin
- Cvt, cytoplasm-to-vacuole pathway
- ER, endoplasmic reticulum
- IMM, inner mitochondrial membrane
- LD, lipid droplets
- NL, neutral lipids
- PA, phosphatidic acid
- PC, phosphatidylcholine
- PCD, programmed cell death
- PE, phosphatidylethanolamine
- PI, phosphatidylinositol
- PL, phospholipids
- PM, plasma membrane
- POA, palmitoleic acid
- PS, phosphatidylserine
- ROS, reactive oxygen species
- TAG, triacylglycerols
- WT, wild-type
- apoptosis
- autophagy
- cellular proteostasis
- lipid metabolism in cellular organelles
- mechanisms of programmed cell death
- mitochondria,
- mitophagy
- plasma membrane
- signal transduction
- yeast
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Affiliation(s)
- Vincent R Richard
- a Department of Biology ; Concordia University ; Montreal , QC Canada
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Burstein MT, Titorenko VI. A mitochondrially targeted compound delays aging in yeast through a mechanism linking mitochondrial membrane lipid metabolism to mitochondrial redox biology. Redox Biol 2014; 2:305-7. [PMID: 24563847 PMCID: PMC3926115 DOI: 10.1016/j.redox.2014.01.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 01/13/2014] [Indexed: 11/29/2022] Open
Abstract
A recent study revealed a mechanism of delaying aging in yeast by a natural compound which specifically impacts mitochondrial redox processes. In this mechanism, exogenously added lithocholic bile acid enters yeast cells, accumulates mainly in the inner mitochondrial membrane, and elicits an age-related remodeling of phospholipid synthesis and movement within both mitochondrial membranes. Such remodeling of mitochondrial phospholipid dynamics progresses with the chronological age of a yeast cell and ultimately causes significant changes in mitochondrial membrane lipidome. These changes in the composition of membrane phospholipids alter mitochondrial abundance and morphology, thereby triggering changes in the age-related chronology of such longevity-defining redox processes as mitochondrial respiration, the maintenance of mitochondrial membrane potential, the preservation of cellular homeostasis of mitochondrially produced reactive oxygen species, and the coupling of electron transport to ATP synthesis.
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Key Words
- Aging
- Anti-aging natural compounds
- CL, cardiolipin
- IMM, inner mitochondrial membrane
- LCA, lithocholic acid
- MLCL, monolysocardiolipin
- Mitochondrial lipids
- Mitochondrial reactive oxygen species
- Mitochondrial redox biology
- Mitochondrial respiration
- OMM, outer mitochondrial membrane
- PA, phosphatidic acid
- PC, phosphatidylcholine
- PE, phosphatidylethanolamine
- PG, phosphatidylglycerol
- PS, phosphatidylserine
- ROS, reactive oxygen species
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Lobasso S, Palese LL, Angelini R, Corcelli A. Relationship between cardiolipin metabolism and oxygen availability in Bacillus subtilis. FEBS Open Bio 2013; 3:151-5. [PMID: 23772387 PMCID: PMC3668533 DOI: 10.1016/j.fob.2013.02.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 02/05/2013] [Accepted: 02/14/2013] [Indexed: 11/23/2022] Open
Abstract
We report changes of the content of anionic phospholipids in Bacillus subtilis in response to hypoxic conditions and inhibition of terminal respiration. Cardiolipin accumulates rapidly when bacteria are suspended in non-growth medium under reduced aeration or exposed to the inhibitor cyanide; the increase of cardiolipin occurs at the expense of its precursor phosphatidylglycerol and is temperature-dependent. Depending on the extent of hypoxic stress, membranes containing different levels of cardiolipin can be isolated from B. subtilis cells. The NADH oxidase activity in cardiolipin-enriched membranes is cyanide-resistant; furthermore O2 consumption measurements indicated that cardiolipin-enriched cells are resistant to cyanide. Results point out a possible interdependence between the effect of cyanide on cardiolipin metabolism and the effect of cardiolipin on the effectiveness of cyanide inhibition.
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Affiliation(s)
- Simona Lobasso
- Department of Basic Medical Sciences, Neuroscience and Sensory Organs, University of Bari "Aldo Moro", Italy
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