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1.
J Cell Biol ; 223(10)2024 Oct 07.
Article in English | MEDLINE | ID: mdl-39007804

ABSTRACT

To breach the basement membrane, cells in development and cancer use large, transient, specialized lipid-rich membrane protrusions. Using live imaging, endogenous protein tagging, and cell-specific RNAi during Caenorhabditis elegans anchor cell (AC) invasion, we demonstrate that the lipogenic SREBP transcription factor SBP-1 drives the expression of the fatty acid synthesis enzymes POD-2 and FASN-1 prior to invasion. We show that phospholipid-producing LPIN-1 and sphingomyelin synthase SMS-1, which use fatty acids as substrates, produce lysosome stores that build the AC's invasive protrusion, and that SMS-1 also promotes protrusion localization of the lipid raft partitioning ZMP-1 matrix metalloproteinase. Finally, we discover that HMG-CoA reductase HMGR-1, which generates isoprenoids for prenylation, localizes to the ER and enriches in peroxisomes at the AC invasive front, and that the final transmembrane prenylation enzyme, ICMT-1, localizes to endoplasmic reticulum exit sites that dynamically polarize to deliver prenylated GTPases for protrusion formation. Together, these results reveal a collaboration between lipogenesis and a polarized lipid prenylation system that drives invasive protrusion formation.


Subject(s)
Basement Membrane , Caenorhabditis elegans Proteins , Caenorhabditis elegans , Endoplasmic Reticulum , Lipogenesis , Animals , Caenorhabditis elegans/metabolism , Caenorhabditis elegans/genetics , Basement Membrane/metabolism , Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans Proteins/genetics , Endoplasmic Reticulum/metabolism , Lipogenesis/genetics , Prenylation , Peroxisomes/metabolism , Cell Movement , Lysosomes/metabolism
2.
J Cell Biol ; 223(10)2024 Oct 07.
Article in English | MEDLINE | ID: mdl-38967608

ABSTRACT

Peroxisomes are membrane-bound organelles harboring metabolic enzymes. In humans, peroxisomes are required for normal development, yet the genes regulating peroxisome function remain unclear. We performed a genome-wide CRISPRi screen to identify novel factors involved in peroxisomal homeostasis. We found that inhibition of RNF146, an E3 ligase activated by poly(ADP-ribose), reduced the import of proteins into peroxisomes. RNF146-mediated loss of peroxisome import depended on the stabilization and activity of the poly(ADP-ribose) polymerases TNKS and TNKS2, which bind the peroxisomal membrane protein PEX14. We propose that RNF146 and TNKS/2 regulate peroxisome import efficiency by PARsylation of proteins at the peroxisome membrane. Interestingly, we found that the loss of peroxisomes increased TNKS/2 and RNF146-dependent degradation of non-peroxisomal substrates, including the ß-catenin destruction complex component AXIN1, which was sufficient to alter the amplitude of ß-catenin transcription. Together, these observations not only suggest previously undescribed roles for RNF146 in peroxisomal regulation but also a novel role in bridging peroxisome function with Wnt/ß-catenin signaling during development.


Subject(s)
Axin Protein , Peroxisomes , Ubiquitin-Protein Ligases , Wnt Signaling Pathway , Peroxisomes/metabolism , Peroxisomes/genetics , Ubiquitin-Protein Ligases/metabolism , Ubiquitin-Protein Ligases/genetics , Humans , Axin Protein/metabolism , Axin Protein/genetics , Membrane Proteins/metabolism , Membrane Proteins/genetics , beta Catenin/metabolism , beta Catenin/genetics , HEK293 Cells , Protein Transport , CRISPR-Cas Systems
3.
Cell Commun Signal ; 22(1): 362, 2024 Jul 15.
Article in English | MEDLINE | ID: mdl-39010102

ABSTRACT

Dihydroorotase (DHOase) is the third enzyme in the six enzymatic reaction steps of the endogenous pyrimidine nucleotide de novo biosynthesis pathway, which is a metabolic pathway conserved in both bacteria and eukaryotes. However, research on the biological function of DHOase in plant pathogenic fungi is very limited. In this study, we identified and named MoPyr4, a homologous protein of Saccharomyces cerevisiae DHOase Ura4, in the rice blast fungus Magnaporthe oryzae and investigated its ability to regulate fungal growth, pathogenicity, and autophagy. Deletion of MoPYR4 led to defects in growth, conidiation, appressorium formation, the transfer and degradation of glycogen and lipid droplets, appressorium turgor accumulation, and invasive hypha expansion in M. oryzae, which eventually resulted in weakened fungal pathogenicity. Long-term replenishment of exogenous uridine-5'-phosphate (UMP) can effectively restore the phenotype and virulence of the ΔMopyr4 mutant. Further study revealed that MoPyr4 also participated in the regulation of the Pmk1-MAPK signaling pathway, co-localized with peroxisomes for the oxidative stress response, and was involved in the regulation of the Osm1-MAPK signaling pathway in response to hyperosmotic stress. In addition, MoPyr4 interacted with MoAtg5, the core protein involved in autophagy, and positively regulated autophagic degradation. Taken together, our results suggested that MoPyr4 for UMP biosynthesis was crucial for the development and pathogenicity of M. oryzae. We also revealed that MoPyr4 played an essential role in the external stress response and pathogenic mechanism through participation in the Pmk1-MAPK signaling pathway, peroxisome-related oxidative stress response mechanism, the Osm1-MAPK signaling pathway and the autophagy pathway.


Subject(s)
Autophagy , Fungal Proteins , Oryza , Fungal Proteins/metabolism , Fungal Proteins/genetics , Oryza/microbiology , Virulence/genetics , Peroxisomes/metabolism , Plant Diseases/microbiology , Ascomycota/pathogenicity , Ascomycota/genetics , Ascomycota/enzymology , MAP Kinase Signaling System , Oxidative Stress
4.
Biosensors (Basel) ; 14(7)2024 Jul 22.
Article in English | MEDLINE | ID: mdl-39056633

ABSTRACT

A coenzyme A (CoA-SH)-responsive dual electrochemical and fluorescence-based sensor was designed utilizing an MnO2-immobilized-polymer-dot (MnO2@D-PD)-coated electrode for the sensitive detection of osteoarthritis (OA) in a peroxisomal ß-oxidation knockout model. The CoA-SH-responsive MnO2@D-PD-coated electrode interacted sensitively with CoA-SH in OA chondrocytes, triggering electroconductivity and fluorescence changes due to cleavage of the MnO2 nanosheet on the electrode. The MnO2@D-PD-coated electrode can detect CoA-SH in immature articular chondrocyte primary cells, as indicated by the significant increase in resistance in the control medium (R24h = 2.17 MΩ). This sensor also sensitively monitored the increase in resistance in chondrocyte cells in the presence of acetyl-CoA inducers, such as phytol (Phy) and sodium acetate (SA), in the medium (R24h = 2.67, 3.08 MΩ, respectively), compared to that in the control medium, demonstrating the detection efficiency of the sensor towards the increase in the CoA-SH concentration. Furthermore, fluorescence recovery was observed owing to MnO2 cleavage, particularly in the Phy- and SA-supplemented media. The transcription levels of OA-related anabolic (Acan) and catabolic factors (Adamts5) in chondrocytes also confirmed the interaction between CoA-SH and the MnO2@D-PD-coated electrode. Additionally, electrode integration with a wireless sensing system provides inline monitoring via a smartphone, which can potentially be used for rapid and sensitive OA diagnosis.


Subject(s)
Biosensing Techniques , Electrodes , Manganese Compounds , Osteoarthritis , Polymers , Manganese Compounds/chemistry , Polymers/chemistry , Oxides/chemistry , Electrochemical Techniques , Oxidation-Reduction , Chondrocytes , Humans , Fluorescence , Peroxisomes/metabolism , Animals
5.
New Phytol ; 243(4): 1472-1489, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38877698

ABSTRACT

Phytophthora parasitica causes diseases on a broad range of host plants. It secretes numerous effectors to suppress plant immunity. However, only a few virulence effectors in P. parasitica have been characterized. Here, we highlight that PpE18, a conserved RXLR effector in P. parasitica, was a virulence factor and suppresses Nicotiana benthamiana immunity. Utilizing luciferase complementation, co-immunoprecipitation, and GST pull-down assays, we determined that PpE18 targeted NbAPX3-1, a peroxisome membrane-associated ascorbate peroxidase with reactive oxygen species (ROS)-scavenging activity and positively regulates plant immunity in N. benthamiana. We show that the ROS-scavenging activity of NbAPX3-1 was critical for its immune function and was hindered by the binding of PpE18. The interaction between PpE18 and NbAPX3-1 resulted in an elevation of ROS levels in the peroxisome. Moreover, we discovered that the ankyrin repeat-containing protein NbANKr2 acted as a positive immune regulator, interacting with both NbAPX3-1 and PpE18. NbANKr2 was required for NbAPX3-1-mediated disease resistance. PpE18 competitively interfered with the interaction between NbAPX3-1 and NbANKr2, thereby weakening plant resistance. Our results reveal an effective counter-defense mechanism by which P. parasitica employed effector PpE18 to suppress host cellular defense, by suppressing biochemical activity and disturbing immune function of NbAPX3-1 during infection.


Subject(s)
Ascorbate Peroxidases , Nicotiana , Peroxisomes , Phytophthora , Plant Immunity , Reactive Oxygen Species , Virulence Factors , Phytophthora/pathogenicity , Phytophthora/physiology , Nicotiana/microbiology , Reactive Oxygen Species/metabolism , Ascorbate Peroxidases/metabolism , Virulence Factors/metabolism , Peroxisomes/metabolism , Plant Diseases/microbiology , Plant Diseases/immunology , Protein Binding , Disease Resistance , Ankyrin Repeat
6.
Metab Eng ; 84: 169-179, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38936763

ABSTRACT

7-Dehydrocholesterol (7-DHC) is widely present in various organisms and is an important precursor of vitamin D3. Despite significant improvements in the biosynthesis of 7-DHC, it remains insufficient to meet the industrial demands. In this study, we reported high-level production of 7-DHC in an industrial Saccharomyces cerevisiae leveraging subcellular organelles. Initially, the copy numbers of DHCR24 were increased in combination with sterol transcriptional factor engineering and rebalanced the redox power of the strain. Subsequently, the effects of compartmentalizing the post-squalene pathway in peroxisomes were validated by assembling various pathway modules in this organelle. Furthermore, several peroxisomes engineering was conducted to enhance the production of 7-DHC. Utilizing the peroxisome as a vessel for partial post-squalene pathways, the potential of yeast for 7-dehydrocholesterol production was demonstrated by achieving a 26-fold increase over the initial production level. 7-DHC titer reached 640.77 mg/L in shake flasks and 4.28 g/L in a 10 L bench-top fermentor, the highest titer ever reported. The present work lays solid foundation for large-scale and cost-effective production of 7-DHC for practical applications.


Subject(s)
Dehydrocholesterols , Metabolic Engineering , Saccharomyces cerevisiae , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Dehydrocholesterols/metabolism , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae Proteins/metabolism , Peroxisomes/metabolism , Peroxisomes/genetics , Diploidy
7.
Methods Mol Biol ; 2792: 265-275, 2024.
Article in English | MEDLINE | ID: mdl-38861094

ABSTRACT

Eukaryotic cells are compartmentalized by membrane-bounded organelles to ensure that specific biochemical reactions and cellular functions occur in a spatially restricted manner. The subcellular localization of proteins is largely determined by their intrinsic targeting signals, which are mainly constituted by short peptides. A complete organelle targeting signal may contain a core signal (CoreS) as well as auxiliary signals (AuxiS). However, the AuxiS is often not as well characterized as the CoreS. Peroxisomes house many key steps in photorespiration, besides other crucial functions in plants. Peroxisome targeting signal type 1 (PTS1), which is carried by most peroxisome matrix proteins, was initially recognized as a C-terminal tripeptide with a "canonical" consensus of [S/A]-[K/R]-[L/M]. Many studies have shown the existence of auxiliary targeting signals upstream of PTS1, but systematic characterizations are lacking. Here, we designed an analytical strategy to characterize the auxiliary targeting signals for plant peroxisomes using large datasets and statistics followed by experimental validations. This method may also be applied to deciphering the auxiliary targeting signals for other organelles, whose organellar targeting depends on a core peptide with assistance from a nearby auxiliary signal.


Subject(s)
Computational Biology , Peroxisomes , Peroxisomes/metabolism , Computational Biology/methods , Protein Transport , Peroxisomal Targeting Signals , Protein Sorting Signals , Plant Proteins/metabolism , Plant Proteins/genetics , Databases, Protein , Amino Acid Sequence
8.
Cell Mol Biol Lett ; 29(1): 85, 2024 Jun 04.
Article in English | MEDLINE | ID: mdl-38834954

ABSTRACT

The molecular basis for bulk autophagy activation due to a deficiency in essential nutrients such as carbohydrates, amino acids, and nitrogen is well understood. Given autophagy functions to reduce surplus to compensate for scarcity, it theoretically possesses the capability to selectively degrade specific substrates to meet distinct metabolic demands. However, direct evidence is still lacking that substantiates the idea that autophagy selectively targets specific substrates (known as selective autophagy) to address particular nutritional needs. Recently, Gross et al. found that during phosphate starvation (P-S), rather than nitrogen starvation (N-S), yeasts selectively eliminate peroxisomes by dynamically altering the composition of the Atg1/ULK kinase complex (AKC) to adapt to P-S. This study elucidates how the metabolite sensor Pho81 flexibly interacts with AKC and guides selective autophagic clearance of peroxisomes during P-S, providing novel insights into the metabolic contribution of autophagy to special nutritional needs.


Subject(s)
Autophagy , Phosphates , Saccharomyces cerevisiae Proteins , Phosphates/metabolism , Phosphates/deficiency , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae Proteins/genetics , Peroxisomes/metabolism , Saccharomyces cerevisiae/metabolism , Autophagy-Related Protein-1 Homolog/metabolism , Autophagy-Related Protein-1 Homolog/genetics , Autophagy-Related Proteins/metabolism , Autophagy-Related Proteins/genetics , Protein Serine-Threonine Kinases/metabolism , Protein Serine-Threonine Kinases/genetics , Protein Kinases
9.
Insect Biochem Mol Biol ; 170: 104139, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38815735

ABSTRACT

Peroxisomes are ubiquitous cellular organelles participating in a variety of critical metabolic reactions. PEX14 is an essential peroxin responsible for peroxisome biogenesis. In this study, we identified the human PEX14 homolog in the brown planthopper, Nilaparvata lugens (Hemiptera: Delphacidae). N. lugens PEX14 (NlPEX14) showed significant topological similarity to its human counterpart. It is expressed throughout all developmental stages, with the highest expression observed in adult insects. Down-regulation of NlPEX14 through injection of NlPEX14-specific double-strand RNA impaired nymphal development. Moreover, females subjected to dsNlPEX14 treatment exhibited a significantly reduced lifespan. Additionally, we found abnormal ovarian development and a significant decrease in the number of eggs laid in NlPEX14-downregulated females. Further experiments support that the shortening of lifespan and the decrease in female fecundity can be attributed, at least partially, to the accumulation of fatty acids and reduced expression of vitellogenin. Together, our study reveals an indispensable function of NlPEX14 for insect reproduction and establishes a causal connection between the phenotypes and peroxisome biogenesis, shedding light on the importance of peroxisomes in female fecundity.


Subject(s)
Fertility , Hemiptera , Insect Proteins , Animals , Hemiptera/genetics , Hemiptera/metabolism , Hemiptera/physiology , Hemiptera/growth & development , Female , Insect Proteins/metabolism , Insect Proteins/genetics , Peroxisomes/metabolism , Longevity , Nymph/growth & development , Nymph/metabolism , Nymph/genetics , Peroxins/metabolism , Peroxins/genetics , Membrane Proteins/metabolism , Membrane Proteins/genetics , Vitellogenins/metabolism , Vitellogenins/genetics
10.
Biochim Biophys Acta Mol Cell Res ; 1871(5): 119742, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38702017

ABSTRACT

Peroxisomes are ubiquitous cell organelles involved in various metabolic pathways. In order to properly function, several cofactors, substrates and products of peroxisomal enzymes need to pass the organellar membrane. So far only a few transporter proteins have been identified. We analysed peroxisomal membrane fractions purified from the yeast Hansenula polymorpha by untargeted label-free quantitation mass spectrometry. As expected, several known peroxisome-associated proteins were enriched in the peroxisomal membrane fraction. In addition, several other proteins were enriched, including mitochondrial transport proteins. Localization studies revealed that one of them, the mitochondrial phosphate carrier Mir1, has a dual localization on mitochondria and peroxisomes. To better understand the molecular mechanisms of dual sorting, we localized Mir1 in cells lacking Pex3 or Pex19, two peroxins that play a role in targeting of peroxisomal membrane proteins. In these cells Mir1 only localized to mitochondria, indicating that Pex3 and Pex19 are required to sort Mir1 to peroxisomes. Analysis of the localization of truncated versions of Mir1 in wild-type H. polymorpha cells revealed that most of them localized to mitochondria, but only one, consisting of the transmembrane domains 3-6, was peroxisomal. Peroxisomal localization of this construct was lost in a MIR1 deletion strain, indicating that full-length Mir1 was required for the localization of the truncated protein to peroxisomes. Our data suggest that only full-length Mir1 sorts to peroxisomes, while Mir1 contains multiple regions with mitochondrial sorting information. Data are available via ProteomeXchange with identifier PXD050324.


Subject(s)
Fungal Proteins , Mitochondria , Peroxisomes , Pichia , Peroxisomes/metabolism , Mitochondria/metabolism , Mitochondria/genetics , Fungal Proteins/metabolism , Fungal Proteins/genetics , Pichia/metabolism , Pichia/genetics , Membrane Proteins/metabolism , Membrane Proteins/genetics , Peroxins/metabolism , Peroxins/genetics , Mitochondrial Proteins/metabolism , Mitochondrial Proteins/genetics , Protein Transport
11.
PLoS One ; 19(5): e0298274, 2024.
Article in English | MEDLINE | ID: mdl-38753762

ABSTRACT

The membrane peroxisomal proteins PEX11, play a crucial role in peroxisome proliferation by regulating elongation, membrane constriction, and fission of pre-existing peroxisomes. In this study, we evaluated the function of PEX11B gene in neural differentiation of human embryonic stem cell (hESC) by inducing shRNAi-mediated knockdown of PEX11B expression. Our results demonstrate that loss of PEX11B expression led to a significant decrease in the expression of peroxisomal-related genes including ACOX1, PMP70, PEX1, and PEX7, as well as neural tube-like structures and neuronal markers. Inhibition of SIRT1 using pharmacological agents counteracted the effects of PEX11B knockdown, resulting in a relative increase in PEX11B expression and an increase in differentiated neural tube-like structures. However, the neuroprotective effects of SIRT1 were eliminated by PPAR inhibition, indicating that PPARÉ£ may mediate the interaction between PEX11B and SIRT1. Our findings suggest that both SIRT1 and PPARÉ£ have neuroprotective effects, and also this study provides the first indication for a potential interaction between PEX11B, SIRT1, and PPARÉ£ during hESC neural differentiation.


Subject(s)
Cell Differentiation , Human Embryonic Stem Cells , Membrane Proteins , PPAR gamma , Sirtuin 1 , Humans , Sirtuin 1/metabolism , Sirtuin 1/genetics , PPAR gamma/metabolism , PPAR gamma/genetics , Cell Differentiation/drug effects , Human Embryonic Stem Cells/metabolism , Human Embryonic Stem Cells/cytology , Human Embryonic Stem Cells/drug effects , Membrane Proteins/metabolism , Membrane Proteins/genetics , Neurons/metabolism , Neurons/cytology , Neurons/drug effects , Cell Line , Peroxisomes/metabolism
12.
Biochim Biophys Acta Mol Cell Res ; 1871(6): 119754, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38762172

ABSTRACT

Peroxisome biogenesis disorders are caused by pathogenic variants in genes involved in biogenesis and maintenance of peroxisomes. However, mitochondria are also often affected in these diseases. Peroxisomal membrane proteins, including PEX14, have been found to mislocalise to mitochondria in cells lacking peroxisomes. Recent studies indicated that this mislocalisation contributes to mitochondrial abnormalities in PEX3-deficient patient fibroblasts cells. Here, we studied whether mitochondrial morphology is also affected in PEX3-deficient HEK293 cells and whether PEX14 mislocalises to mitochondria in these cells. Using high-resolution imaging techniques, we show that although endogenous PEX14 mislocalises to mitochondria, mitochondrial morphology was normal in PEX3-KO HEK293 cells. However, we discovered that overexpression of tagged PEX14 in wild-type HEK293 cells resulted in its mitochondrial localisation, accompanied by altered mitochondrial morphology. Our data indicate that overexpression of tagged PEX14 alone directly or indirectly cause mitochondrial abnormalities in cells containing peroxisomes.


Subject(s)
Membrane Proteins , Mitochondria , Peroxisomes , Humans , Mitochondria/metabolism , Mitochondria/genetics , Membrane Proteins/metabolism , Membrane Proteins/genetics , HEK293 Cells , Peroxisomes/metabolism , Peroxisomes/genetics , Peroxins/metabolism , Peroxins/genetics , Protein Transport , Lipoproteins , Repressor Proteins
13.
Free Radic Biol Med ; 221: 81-88, 2024 Aug 20.
Article in English | MEDLINE | ID: mdl-38762061

ABSTRACT

Androgen receptor (AR)-targeting therapy induces oxidative stress in prostate cancer. However, the mechanism of oxidative stress induction by AR-targeting therapy remains unclear. This study investigated the mechanism of oxidative stress induction by AR-targeting therapy, with the aim to develop novel therapeutics targeting oxidative stress induced by AR-targeting therapy. Intracellular reactive oxygen species (ROS) was examined by fluorescence microscopy and flow cytometry analysis. The effects of silencing gene expression and small molecule inhibitors on gene expression and cytotoxic effects were examined by quantitative real-time PCR and cell proliferation assay. ROS induced by androgen depletion co-localized with peroxisomes in prostate cancer cells. Among peroxisome-related genes, PPARA was commonly induced by AR inhibition and involved in ROS production via PKC signaling. Inhibition of PPARα by specific siRNA and a small molecule inhibitor suppressed cell proliferation and increased cellular sensitivity to the antiandrogen enzalutamide in prostate cancer cells. This study revealed a novel pathway by which AR inhibition induced intracellular ROS mainly in peroxisomes through PPARα activation in prostate cancer. This pathway is a promising target for the development of novel therapeutics for prostate cancer in combination with AR-targeting therapy such as antiandrogen enzalutamide.


Subject(s)
Benzamides , Cell Proliferation , Drug Resistance, Neoplasm , Nitriles , Oxidative Stress , Peroxisomes , Phenylthiohydantoin , Prostatic Neoplasms , Receptors, Androgen , Humans , Male , Androgen Receptor Antagonists/pharmacology , Benzamides/pharmacology , Cell Line, Tumor , Cell Proliferation/drug effects , Drug Resistance, Neoplasm/drug effects , Gene Expression Regulation, Neoplastic/drug effects , Nitriles/pharmacology , Oxidative Stress/drug effects , Peroxisomes/metabolism , Peroxisomes/drug effects , Phenylthiohydantoin/pharmacology , PPAR alpha/metabolism , PPAR alpha/genetics , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/drug therapy , Prostatic Neoplasms/pathology , Prostatic Neoplasms/genetics , Reactive Oxygen Species/metabolism , Receptors, Androgen/metabolism , Receptors, Androgen/genetics , RNA, Small Interfering/genetics , Signal Transduction/drug effects
14.
Nat Commun ; 15(1): 4314, 2024 May 21.
Article in English | MEDLINE | ID: mdl-38773129

ABSTRACT

Peroxisomes are eukaryotic organelles that are essential for multiple metabolic pathways, including fatty acid oxidation, degradation of amino acids, and biosynthesis of ether lipids. Consequently, peroxisome dysfunction leads to pediatric-onset neurodegenerative conditions, including Peroxisome Biogenesis Disorders (PBD). Due to the dynamic, tissue-specific, and context-dependent nature of their biogenesis and function, live cell imaging of peroxisomes is essential for studying peroxisome regulation, as well as for the diagnosis of PBD-linked abnormalities. However, the peroxisomal imaging toolkit is lacking in many respects, with no reporters for substrate import, nor cell-permeable probes that could stain dysfunctional peroxisomes. Here we report that the BODIPY-C12 fluorescent fatty acid probe stains functional and dysfunctional peroxisomes in live mammalian cells. We then go on to improve BODIPY-C12, generating peroxisome-specific reagents, PeroxiSPY650 and PeroxiSPY555. These probes combine high peroxisome specificity, bright fluorescence in the red and far-red spectrum, and fast non-cytotoxic staining, making them ideal tools for live cell, whole organism, or tissue imaging of peroxisomes. Finally, we demonstrate that PeroxiSPY enables diagnosis of peroxisome abnormalities in the PBD CRISPR/Cas9 cell models and patient-derived cell lines.


Subject(s)
Boron Compounds , Fatty Acids , Fluorescent Dyes , Peroxisomal Disorders , Peroxisomes , Peroxisomes/metabolism , Humans , Fatty Acids/metabolism , Fluorescent Dyes/chemistry , Boron Compounds/chemistry , Peroxisomal Disorders/metabolism , Animals
16.
Int J Biochem Cell Biol ; 172: 106585, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38734232

ABSTRACT

Tamoxifen is an estrogen receptor modulator that has been reported to alleviate hepatic lipid accumulation in mice, but the mechanism is still unclear. Peroxisome fatty acid ß-oxidation is the main metabolic pathway for the overload of long-chain fatty acids. As long-chain fatty acids are a cause of hepatic lipid accumulation, the activation of peroxisome fatty acid ß-oxidation might be a novel therapeutic strategy for metabolic associated fatty liver disease. In this study, we investigated the mechanism of tamoxifen against hepatic lipid accumulation based on the activation of peroxisome fatty acid ß-oxidation. Tamoxifen reduced liver long-chain fatty acids and relieved hepatic lipid accumulation in high fat diet mice without sex difference. In vitro, tamoxifen protected primary hepatocytes against palmitic acid-induced lipotoxicity. Mechanistically, the RNA-sequence of hepatocytes isolated from the liver revealed that peroxisome fatty acid ß-oxidation was activated by tamoxifen. Protein and mRNA expression of enoyl CoA hydratase and 3-hydroxyacyl CoA hydratase were significantly increased in vivo and in vitro. Small interfering RNA enoyl CoA hydratase and 3-hydroxyacyl CoA hydratase in primary hepatocytes abolished the therapeutic effects of tamoxifen in lipid accumulation. In conclusion, our results indicated that tamoxifen could relieve hepatic lipid accumulation in high fat diet mice based on the activation of enoyl CoA hydratase and 3-hydroxyacyl CoA hydratase-mediated peroxisome fatty acids ß-oxidation.


Subject(s)
Enoyl-CoA Hydratase , Hepatocytes , Lipid Metabolism , Liver , Mice, Inbred C57BL , Oxidation-Reduction , Peroxisomes , Tamoxifen , Animals , Tamoxifen/pharmacology , Mice , Lipid Metabolism/drug effects , Liver/metabolism , Liver/drug effects , Hepatocytes/metabolism , Hepatocytes/drug effects , Oxidation-Reduction/drug effects , Male , Peroxisomes/metabolism , Peroxisomes/drug effects , Enoyl-CoA Hydratase/metabolism , Enoyl-CoA Hydratase/genetics , Up-Regulation/drug effects , Diet, High-Fat/adverse effects , Female , Fatty Acids/metabolism
17.
Int J Biol Macromol ; 270(Pt 2): 132227, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38734339

ABSTRACT

Fusarium crown rot, caused by Fusarium pseudograminearum, is a devastating disease affecting the yield and quality of cereal crops. Peroxisomes are single-membrane organelles that play a critical role in various biological processes in eukaryotic cells. To functionally characterise peroxisome biosynthetic receptor proteins FpPEX5 and FpPEX7 in F. pseudograminearum, we constructed deletion mutants, ΔFpPEX5 and ΔFpPEX7, and complementary strains, ΔFpPEX5-C and ΔFpPEX7-C, and analysed the functions of FpPEX5 and FpPEX7 proteins using various phenotypic observations. The deletion of FpPEX5 and FpPEX7 resulted in a significant deficiency in mycelial growth and conidiation and blocked the peroxisomal targeting signal 1 and peroxisomal targeting signal 2 pathways, which are involved in peroxisomal matrix protein transport, increasing the accumulation of lipid droplets and reactive oxygen species. The deletion of FpPEX5 and FpPEX7 may reduce the formation of toxigenic bodies and decrease the pathogenicity of F. pseudograminearum. These results indicate that FpPEX5 and FpPEX7 play vital roles in the growth, asexual reproduction, virulence, and fatty acid utilisation of F. pseudograminearum. This study provides a theoretical basis for controlling stem rot in wheat.


Subject(s)
Fungal Proteins , Fusarium , Peroxisomes , Fusarium/pathogenicity , Fusarium/genetics , Fusarium/metabolism , Fusarium/growth & development , Fungal Proteins/genetics , Fungal Proteins/metabolism , Virulence/genetics , Peroxisomes/metabolism , Peroxisomes/genetics , Trichothecenes/metabolism , Plant Diseases/microbiology , Spores, Fungal/growth & development , Triticum/microbiology , Reactive Oxygen Species/metabolism , Peroxisome-Targeting Signal 1 Receptor/genetics , Peroxisome-Targeting Signal 1 Receptor/metabolism , Gene Deletion , Gene Expression Regulation, Fungal , Peroxisomal Targeting Signal 2 Receptor , Mycelium/growth & development , Mycelium/metabolism
18.
J Cell Sci ; 137(9)2024 May 01.
Article in English | MEDLINE | ID: mdl-38752931

ABSTRACT

Peroxisomes are highly plastic organelles that are involved in several metabolic processes, including fatty acid oxidation, ether lipid synthesis and redox homeostasis. Their abundance and activity are dynamically regulated in response to nutrient availability and cellular stress. Damaged or superfluous peroxisomes are removed mainly by pexophagy, the selective autophagy of peroxisomes induced by ubiquitylation of peroxisomal membrane proteins or ubiquitin-independent processes. Dysregulated pexophagy impairs peroxisome homeostasis and has been linked to the development of various human diseases. Despite many recent insights into mammalian pexophagy, our understanding of this process is still limited compared to our understanding of pexophagy in yeast. In this Cell Science at a Glance article and the accompanying poster, we summarize current knowledge on the control of mammalian pexophagy and highlight which aspects require further attention. We also discuss the role of ubiquitylation in pexophagy and describe the ubiquitin machinery involved in regulating signals for the recruitment of phagophores to peroxisomes.


Subject(s)
Peroxisomes , Ubiquitination , Peroxisomes/metabolism , Humans , Animals , Autophagy , Macroautophagy , Mammals/metabolism , Membrane Proteins/metabolism , Membrane Proteins/genetics
19.
PLoS Biol ; 22(4): e3002602, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38669296

ABSTRACT

Mitofusins are large GTPases that trigger fusion of mitochondrial outer membranes. Similarly to the human mitofusin Mfn2, which also tethers mitochondria to the endoplasmic reticulum (ER), the yeast mitofusin Fzo1 stimulates contacts between Peroxisomes and Mitochondria when overexpressed. Yet, the physiological significance and function of these "PerMit" contacts remain unknown. Here, we demonstrate that Fzo1 naturally localizes to peroxisomes and promotes PerMit contacts in physiological conditions. These contacts are regulated through co-modulation of Fzo1 levels by the ubiquitin-proteasome system (UPS) and by the desaturation status of fatty acids (FAs). Contacts decrease under low FA desaturation but reach a maximum during high FA desaturation. High-throughput genetic screening combined with high-resolution cellular imaging reveal that Fzo1-mediated PerMit contacts favor the transit of peroxisomal citrate into mitochondria. In turn, citrate enters the TCA cycle to stimulate the mitochondrial membrane potential and maintain efficient mitochondrial fusion upon high FA desaturation. These findings thus unravel a mechanism by which inter-organelle contacts safeguard mitochondrial fusion.


Subject(s)
Mitochondria , Mitochondrial Dynamics , Peroxisomes , Saccharomyces cerevisiae Proteins , Saccharomyces cerevisiae , Peroxisomes/metabolism , Mitochondrial Dynamics/physiology , Mitochondria/metabolism , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae Proteins/genetics , Fatty Acids/metabolism , GTP Phosphohydrolases/metabolism , GTP Phosphohydrolases/genetics , Mitochondrial Proteins/metabolism , Mitochondrial Proteins/genetics , Endoplasmic Reticulum/metabolism , Membrane Proteins/metabolism , Membrane Proteins/genetics , Proteasome Endopeptidase Complex/metabolism , Citric Acid Cycle , Membrane Potential, Mitochondrial/physiology , Mitochondrial Membranes/metabolism , Humans
20.
Cell Mol Life Sci ; 81(1): 190, 2024 Apr 22.
Article in English | MEDLINE | ID: mdl-38649521

ABSTRACT

The high-protein diet (HPD) has emerged as a potent dietary approach to curb obesity. Peroxisome, a highly malleable organelle, adapts to nutritional changes to maintain homeostasis by remodeling its structure, composition, and quantity. However, the impact of HPD on peroxisomes and the underlying mechanism remains elusive. Using Drosophila melanogaster as a model system, we discovered that HPD specifically increases peroxisome levels within the adipose tissues. This HPD-induced peroxisome elevation is attributed to cysteine and methionine by triggering the expression of CG33474, a fly homolog of mammalian PEX11G. Both the overexpression of Drosophila CG33474 and human PEX11G result in increased peroxisome size. In addition, cysteine and methionine diets both reduce lipid contents, a process that depends on the presence of CG33474. Furthermore, CG33474 stimulates the breakdown of neutral lipids in a cell-autonomous manner. Moreover, the expression of CG33474 triggered by cysteine and methionine requires TOR signaling. Finally, we found that CG33474 promotes inter-organelle contacts between peroxisomes and lipid droplets (LDs), which might be a potential mechanism for CG33474-induced fat loss. In summary, our findings demonstrate that CG33474/PEX11G may serve as an essential molecular bridge linking HPD to peroxisome dynamics and lipid metabolism.


Subject(s)
Adipose Tissue , Cysteine , Drosophila Proteins , Drosophila melanogaster , Methionine , Peroxisomes , Animals , Methionine/metabolism , Peroxisomes/metabolism , Drosophila Proteins/metabolism , Drosophila Proteins/genetics , Drosophila melanogaster/metabolism , Drosophila melanogaster/genetics , Cysteine/metabolism , Adipose Tissue/metabolism , Humans , Lipid Metabolism , Lipid Droplets/metabolism , Signal Transduction , Diet
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