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Cells Jun 2022The AAA-ATPases Pex1 and Pex6 are required for the formation and maintenance of peroxisomes, membrane-bound organelles that harbor enzymes for specialized metabolism.... (Review)
Review
The AAA-ATPases Pex1 and Pex6 are required for the formation and maintenance of peroxisomes, membrane-bound organelles that harbor enzymes for specialized metabolism. Together, Pex1 and Pex6 form a heterohexameric AAA-ATPase capable of unfolding substrate proteins via processive threading through a central pore. Here, we review the proposed roles for Pex1/Pex6 in peroxisome biogenesis and degradation, discussing how the unfolding of potential substrates contributes to peroxisome homeostasis. We also consider how advances in cryo-EM, computational structure prediction, and mechanisms of related ATPases are improving our understanding of how Pex1/Pex6 converts ATP hydrolysis into mechanical force. Since mutations in and cause the majority of known cases of peroxisome biogenesis disorders such as Zellweger syndrome, insights into Pex1/Pex6 structure and function are important for understanding peroxisomes in human health and disease.
Topics: ATPases Associated with Diverse Cellular Activities; Adenosine Triphosphatases; Homeostasis; Humans; Membrane Proteins; Peroxisomes
PubMed: 35805150
DOI: 10.3390/cells11132067 -
Biochemical Society Transactions Dec 2023Plant organelles predominantly rely on the actin cytoskeleton and the myosin motors for long-distance trafficking, while using microtubules and the kinesin motors mostly...
Plant organelles predominantly rely on the actin cytoskeleton and the myosin motors for long-distance trafficking, while using microtubules and the kinesin motors mostly for short-range movement. The distribution and motility of organelles in the plant cell are fundamentally important to robust plant growth and defense. Chloroplasts, mitochondria, and peroxisomes are essential organelles in plants that function independently and coordinately during energy metabolism and other key metabolic processes. In response to developmental and environmental stimuli, these energy organelles modulate their metabolism, morphology, abundance, distribution and motility in the cell to meet the need of the plant. Consistent with their metabolic links in processes like photorespiration and fatty acid mobilization is the frequently observed inter-organellar physical interaction, sometimes through organelle membranous protrusions. The development of various organelle-specific fluorescent protein tags has allowed the simultaneous visualization of organelle movement in living plant cells by confocal microscopy. These energy organelles display an array of morphology and movement patterns and redistribute within the cell in response to changes such as varying light conditions, temperature fluctuations, ROS-inducible treatments, and during pollen tube development and immune response, independently or in association with one another. Although there are more reports on the mechanism of chloroplast movement than that of peroxisomes and mitochondria, our knowledge of how and why these three energy organelles move and distribute in the plant cell is still scarce at the functional and mechanistic level. It is critical to identify factors that control organelle motility coupled with plant growth, development, and stress response.
Topics: Organelles; Actin Cytoskeleton; Peroxisomes; Chloroplasts; Mitochondria; Microtubules
PubMed: 37975429
DOI: 10.1042/BST20221093 -
Small GTPases 2021Mitochondria and peroxisomes are highly dynamic, multifunctional organelles. Both perform key roles for cellular physiology and homoeostasis by mediating bioenergetics,... (Review)
Review
Mitochondria and peroxisomes are highly dynamic, multifunctional organelles. Both perform key roles for cellular physiology and homoeostasis by mediating bioenergetics, biosynthesis, and/or signalling. To support cellular function, they must be properly distributed, of proper size, and be able to interact with other organelles. Accumulating evidence suggests that the small atypical GTPase Miro provides a central signalling node to coordinate mitochondrial as well as peroxisomal dynamics. In this review, I summarize our current understanding of Miro-dependent functions and molecular mechanisms underlying the proper distribution, size and function of mitochondria and peroxisomes.
Topics: Animals; GTP Phosphohydrolases; Homeostasis; Humans; Mitochondria; Mitochondrial Dynamics; Peroxisomes; Signal Transduction
PubMed: 33183150
DOI: 10.1080/21541248.2020.1843957 -
Journal of Cell Science May 2020Peroxisomes are single-membrane organelles present in eukaryotes. The functional importance of peroxisomes in humans is represented by peroxisome-deficient peroxisome... (Review)
Review
Peroxisomes are single-membrane organelles present in eukaryotes. The functional importance of peroxisomes in humans is represented by peroxisome-deficient peroxisome biogenesis disorders (PBDs), including Zellweger syndrome. Defects in the genes that encode the 14 peroxins that are required for peroxisomal membrane assembly, matrix protein import and division have been identified in PBDs. A number of recent findings have advanced our understanding of the biology, physiology and consequences of functional defects in peroxisomes. In this Review, we discuss a cooperative cell defense mechanisms against oxidative stress that involves the localization of BAK (also known as BAK1) to peroxisomes, which alters peroxisomal membrane permeability, resulting in the export of catalase, a peroxisomal enzyme. Another important recent finding is the discovery of a nucleoside diphosphate kinase-like protein that has been shown to be essential for how the energy GTP is generated and provided for the fission of peroxisomes. With regard to PBDs, we newly identified a mild mutation, Pex26-F51L that causes only hearing loss. We will also discuss findings from a new PBD model mouse defective in Pex14, which manifested dysregulation of the BDNF-TrkB pathway, an essential signaling pathway in cerebellar morphogenesis. Here, we thus aim to provide a current view of peroxisome biogenesis and the molecular pathogenesis of PBDs.
Topics: Animals; Intracellular Membranes; Mice; Peroxins; Peroxisomal Disorders; Peroxisomes; Protein Transport
PubMed: 32393673
DOI: 10.1242/jcs.236943 -
International Journal of Molecular... Jul 2020Mitochondria and peroxisomes are ubiquitous subcellular organelles that are highly dynamic and possess a high degree of plasticity. These organelles proliferate through... (Review)
Review
Mitochondria and peroxisomes are ubiquitous subcellular organelles that are highly dynamic and possess a high degree of plasticity. These organelles proliferate through division of pre-existing organelles. Studies on yeast, mammalian cells, and unicellular algae have led to a surprising finding that mitochondria and peroxisomes share the components of their division machineries. At the heart of the mitochondrial and peroxisomal division machineries is a GTPase dynamin-like protein, Dnm1/Drp1, which forms a contractile ring around the neck of the dividing organelles. During division, Dnm1/Drp1 functions as a motor protein and constricts the membrane. This mechanochemical work is achieved by utilizing energy from GTP hydrolysis. Over the last two decades, studies have focused on the structure and assembly of Dnm1/Drp1 molecules around the neck. However, the regulation of GTP during the division of mitochondrion and peroxisome is not well understood. Here, we review the current understanding of Dnm1/Drp1-mediated divisions of mitochondria and peroxisomes, exploring the mechanisms of GTP regulation during the Dnm1/Drp1 function, and provide new perspectives on their potential contribution to mitochondrial and peroxisomal biogenesis.
Topics: Animals; Cell Division; Dynamins; GTP Phosphohydrolases; Humans; Mitochondria; Mitochondrial Dynamics; Mitochondrial Proteins; Molecular Motor Proteins; Peroxisomes; Saccharomyces cerevisiae Proteins
PubMed: 32751702
DOI: 10.3390/ijms21155452 -
Current Opinion in Cell Biology Oct 2023Membrane-bound organelles allow cells to traffic cargo and separate and regulate metabolic pathways. While many organelles are generated by the growth and division of... (Review)
Review
Membrane-bound organelles allow cells to traffic cargo and separate and regulate metabolic pathways. While many organelles are generated by the growth and division of existing organelles, some can also be produced de novo, often in response to metabolic cues. This review will discuss recent advances in our understanding of the early steps in the de novo biogenesis of peroxisomes, lipid droplets, lipoproteins, and autophagosomes. These organelles play critical roles in cellular lipid metabolism and other processes, and their dysfunction causes or is linked to several human diseases. The de novo biogenesis of these organelles occurs in or near the endoplasmic reticulum membrane. This review summarizes recent progress and highlights open questions.
Topics: Humans; Peroxisomes; Lipid Droplets; Autophagosomes; Endoplasmic Reticulum; Lipid Metabolism; Lipoproteins
PubMed: 37531895
DOI: 10.1016/j.ceb.2023.102210 -
The New Phytologist Feb 2020Peroxisomes are small, ubiquitous organelles that are delimited by a single membrane and lack genetic material. However, these simple-structured organelles are highly... (Review)
Review
Peroxisomes are small, ubiquitous organelles that are delimited by a single membrane and lack genetic material. However, these simple-structured organelles are highly versatile in morphology, abundance and protein content in response to various developmental and environmental cues. In plants, peroxisomes are essential for growth and development and perform diverse metabolic functions, many of which are carried out coordinately by peroxisomes and other organelles physically interacting with peroxisomes. Recent studies have added greatly to our knowledge of peroxisomes, addressing areas such as the diverse proteome, regulation of division and protein import, pexophagy, matrix protein degradation, solute transport, signaling, redox homeostasis and various metabolic and physiological functions. This review summarizes our current understanding of plant peroxisomes, focusing on recent discoveries. Current problems and future efforts required to better understand these organelles are also discussed. An improved understanding of peroxisomes will be important not only to the understanding of eukaryotic cell biology and metabolism, but also to agricultural efforts aimed at improving crop performance and defense.
Topics: Computational Biology; Gene Expression Regulation, Plant; Peroxisomes; Plant Cells; Plants; Proteomics
PubMed: 31442305
DOI: 10.1111/nph.16134 -
Current Genetics Apr 2022Peroxisomes are single membrane-bound organelles ubiquitously present in several cell types and are associated with cell and tissue-specific functions. Their role in...
Peroxisomes are single membrane-bound organelles ubiquitously present in several cell types and are associated with cell and tissue-specific functions. Their role in cellular ageing is under investigation in various model systems. Metabolism of cellular reactive oxygen species is a universal function performed by these organelles. In this study, we investigated alterations in peroxisome number upon early replicative ageing of yeast cells. Increase in the number of peroxisomes in replicatively aged mother cells of wild-type yeast was observed when cultured in both peroxisome-inducing and non-inducing medium. Further, we investigated if this increase in peroxisome number in replicatively aged cells is due to enhanced peroxisome proliferation. For this, the number of peroxisomes in replicatively aged mother cells of pex11, pex25 and pex11pex25 was analysed. Increased percentage of aged cells was observed in pex25 and pex11pex25 cells cultured in peroxisome-inducing oleic acid medium. Interestingly, when cultured in oleic acid, young mother cells devoid of Pex11 showed reduced peroxisome proliferation compared to old mother cells. Induced activity of the antioxidant enzyme catalase and reduced accumulation of reactive oxygen species were reported in all studied strains when cultured in oleic acid medium. Further, our data also suggest that replicatively aged cells with increased peroxisome number also display mitochondrial dysfunction and fragmentation in all the strains studied. In conclusion, our data suggests a correlation between increase in peroxisome number and replicative age of yeast cells and interestingly this increase seems to be partly dependent on the fission proteins.
Topics: Cell Proliferation; Membrane Proteins; Peroxins; Peroxisomes; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins
PubMed: 35220444
DOI: 10.1007/s00294-022-01233-3 -
The Journal of Eukaryotic Microbiology Nov 2022Kinetoplastea and Diplonemea possess peroxisome-related organelles that, uniquely, contain most of the enzymes of the glycolytic pathway and are hence called glycosomes.... (Review)
Review
Kinetoplastea and Diplonemea possess peroxisome-related organelles that, uniquely, contain most of the enzymes of the glycolytic pathway and are hence called glycosomes. Enzymes of several other core metabolic pathways have also been located in glycosomes, in addition to some characteristic peroxisomal systems such as pathways of lipid metabolism. A considerable amount of research has been performed on glycosomes of trypanosomes since their discovery four decades ago. Not only the role of the glycosomal enzyme systems in the overall cell metabolism appeared to be unique, but also the organelles display remarkable features regarding their biogenesis and structural properties. These features are similar to those of the well-studied peroxisomes of mammalian and plant cells and yeasts yet exhibit also differences reflecting the large evolutionary distance between these protists and the representatives of other major eukaryotic lineages. Despite all research performed, many questions remain about various properties and the biological roles of glycosomes and peroxisomes. Here, we review the current knowledge about glycosomes, often comparing it with information about peroxisomes. Furthermore, we highlight particularly many questions that remain about the biogenesis, and the heterogeneity in structure and content of these enigmatic organelles, and the properties of their boundary membrane.
Topics: Animals; Microbodies; Peroxisomes; Trypanosoma; Euglenozoa; Homeostasis; Mammals
PubMed: 35175680
DOI: 10.1111/jeu.12897 -
Plant Science : An International... Dec 2020High quality transmission electron micrographs have played a major role in shaping our views on organelles in plant cells. However, these snapshots of dead, fixed and... (Review)
Review
High quality transmission electron micrographs have played a major role in shaping our views on organelles in plant cells. However, these snapshots of dead, fixed and sectioned tissue do not automatically convey an appreciation of the dynamic nature of organelles in living cells. Advances in the imaging of subcellular structures in living cells using multicoloured, targeted fluorescent proteins reveal considerable changes in organelle pleomorphy that might be limited to small regions of the cell. The fresh data and insights also challenge several existing ideas on organelle behaviour and interactivity. Here, using succinct examples from plastids, mitochondria, peroxisomes, and the endoplasmic reticulum I present an evolving view of subcellular dynamics in the plant cell.
Topics: Endoplasmic Reticulum; Mitochondria; Organelle Shape; Organelles; Peroxisomes; Plant Cells; Plastids
PubMed: 33218631
DOI: 10.1016/j.plantsci.2020.110662