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Biological Chemistry May 2017In peroxisomal matrix protein import two processes directly depend on the binding and hydrolysis of ATP, both taking place at the late steps of the peroxisomal import... (Review)
Review
In peroxisomal matrix protein import two processes directly depend on the binding and hydrolysis of ATP, both taking place at the late steps of the peroxisomal import cycle. First, ATP hydrolysis is required to initiate a ubiquitin-transfer cascade to modify the import (co-)receptors. These receptors display a dual localization in the cytosol and at the peroxisomal membrane, whereas only the membrane bound fraction receives the ubiquitin modification. The second ATP-dependent process of the import cycle is carried out by the two AAA+-proteins Pex1p and Pex6p. These ATPases form a heterohexameric complex, which is recruited to the peroxisomal import machinery by the membrane anchor protein Pex15p. The Pex1p/Pex6p complex recognizes the ubiquitinated import receptors, pulls them out of the membrane and releases them into the cytosol. There the deubiquitinated receptors are provided for further rounds of import. ATP binding and hydrolysis are required for Pex1p/Pex6p complex formation and receptor export. In this review, we summarize the current knowledge on the peroxisomal import cascade. In particular, we will focus on the ATP-dependent processes, which are so far best understood in the model organism Saccharomyces cerevisiae.
Topics: Adenosine Triphosphate; Animals; Humans; Peroxisomes; Protein Transport; Saccharomyces cerevisiae Proteins; Ubiquitination
PubMed: 27977397
DOI: 10.1515/hsz-2016-0293 -
Physiological Reviews Jan 2018Peroxisomes are highly dynamic intracellular organelles involved in a variety of metabolic functions essential for the metabolism of long-chain fatty acids, d-amino... (Review)
Review
Peroxisomes are highly dynamic intracellular organelles involved in a variety of metabolic functions essential for the metabolism of long-chain fatty acids, d-amino acids, and many polyamines. A byproduct of peroxisomal metabolism is the generation, and subsequent detoxification, of reactive oxygen and nitrogen species, particularly hydrogen peroxide (HO). Because of its relatively low reactivity (as a mild oxidant), HO has a comparatively long intracellular half-life and a high diffusion rate, all of which makes HO an efficient signaling molecule. Peroxisomes also have intricate connections to mitochondria, and both organelles appear to play important roles in regulating redox signaling pathways. Peroxisomal proteins are also subject to oxidative modification and inactivation by the reactive oxygen and nitrogen species they generate, but the peroxisomal LonP2 protease can selectively remove such oxidatively damaged proteins, thus prolonging the useful lifespan of the organelle. Peroxisomal homeostasis must adapt to the metabolic state of the cell, by a combination of peroxisome proliferation, the removal of excess or badly damaged organelles by autophagy (pexophagy), as well as by processes of peroxisome inheritance and motility. More recently the tumor suppressors ataxia telangiectasia mutate (ATM) and tuberous sclerosis complex (TSC), which regulate mTORC1 signaling, have been found to regulate pexophagy in response to variable levels of certain reactive oxygen and nitrogen species. It is now clear that any significant loss of peroxisome homeostasis can have devastating physiological consequences. Peroxisome dysregulation has been implicated in several metabolic diseases, and increasing evidence highlights the important role of diminished peroxisomal functions in aging processes.
Topics: Animals; Homeostasis; Humans; Hydrogen Peroxide; Mitochondria; Peroxisomes; Proteostasis; Reactive Oxygen Species
PubMed: 29167332
DOI: 10.1152/physrev.00033.2016 -
Current Opinion in Cell Biology Feb 2018Peroxisome biogenesis is governed by molecular machineries, which are either unique to peroxisomes or are partially shared with mitochondria. As peroxisomes have... (Review)
Review
Peroxisome biogenesis is governed by molecular machineries, which are either unique to peroxisomes or are partially shared with mitochondria. As peroxisomes have important protective functions in the cell, modulation of their number is important for human health and disease. Significant progress has been made towards our understanding of the mechanisms of peroxisome formation, revealing a remarkable plasticity of the peroxisome biogenesis pathway. Here we discuss most recent findings with particular focus on peroxisome formation in mammalian cells.
Topics: Animals; Humans; Intracellular Membranes; Metabolic Networks and Pathways; Mitochondria; Organelle Biogenesis; Peroxisomes
PubMed: 29475136
DOI: 10.1016/j.ceb.2018.02.002 -
Brain Pathology (Zurich, Switzerland) Nov 2015Peroxisomes are organelles with diverse metabolic tasks including essential roles in lipid metabolism. They are of utmost importance for the normal functioning of the... (Review)
Review
Peroxisomes are organelles with diverse metabolic tasks including essential roles in lipid metabolism. They are of utmost importance for the normal functioning of the nervous system as most peroxisomal disorders are accompanied with neurological symptoms. Remarkably, the cerebellum exquisitely depends on intact peroxisomal function both during development and adulthood. In this review, we cover all aspects of cerebellar pathology that were reported in peroxisome biogenesis disorders and in diseases caused by dysfunction of the peroxisomal α-oxidation, β-oxidation or ether lipid synthesis pathways. We also discuss the phenotypes of mouse models in which cerebellar pathologies were recapitulated and search for connections with the metabolic abnormalities. It becomes increasingly clear that besides the most severe forms of peroxisome dysfunction that are associated with developmental cerebellar defects, milder impairments can give rise to ataxia later in life.
Topics: Animals; Cerebellum; Humans; Oxidation-Reduction; Peroxisomal Disorders; Peroxisomes
PubMed: 26201894
DOI: 10.1111/bpa.12290 -
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 -
Trends in Biochemical Sciences Mar 2018The eukaryotic cell is organized as a complex grid system where membrane-bound cellular compartments, organelles, must be localized to the right place at the right time.... (Review)
Review
The eukaryotic cell is organized as a complex grid system where membrane-bound cellular compartments, organelles, must be localized to the right place at the right time. One way to facilitate correct organelle localization and organelle cooperation is through membrane contact sites, areas of close proximity between two organelles that are bridged by protein/lipid complexes. It is now clear that all organelles physically contact each other. The main focus of this review is contact sites of peroxisomes, central metabolic hubs whose defects lead to a variety of diseases. New peroxisome contacts, their tethering complexes and functions have been recently discovered. However, if and how peroxisome contacts contribute to the development of peroxisome-related diseases is still a mystery.
Topics: Animals; Disease; Humans; Organelles; Peroxisomes
PubMed: 29395653
DOI: 10.1016/j.tibs.2018.01.001 -
Free Radical Biology & Medicine Mar 2023Plant peroxisomes are highly dynamic organelles with regard to metabolic pathways, number and morphology and participate in different metabolic processes and cell... (Review)
Review
Plant peroxisomes are highly dynamic organelles with regard to metabolic pathways, number and morphology and participate in different metabolic processes and cell responses to their environment. Peroxisomes from animal and plant cells house a complex system of reactive oxygen species (ROS) production associated to different metabolic pathways which are under control of an important set of enzymatic and non enzymatic antioxidative defenses. Nitric oxide (NO) and its derivate reactive nitrogen species (RNS) are also produced in these organelles. Peroxisomes can regulate ROS and NO/RNS levels to allow their role as signalling molecules. The metabolism of other reactive species such as carbonyl reactive species (CRS) and sulfur reactive species (SRS) in peroxisomes and their relationship with ROS and NO have not been explored in depth. In this review, we define a peroxisomal reactive species interactome (PRSI), including all reactive species ROS, RNS, CRS and SRS, their interaction and effect on target molecules contributing to the dynamic redox/ROS homeostasis and plasticity of peroxisomes, enabling fine-tuned regulation of signalling networks associated with peroxisome-dependent HO. Particular attention will be paid to update the information available on HO-dependent peroxisomal retrograde signalling and to discuss a specific peroxisomal footprint.
Topics: Animals; Reactive Oxygen Species; Hydrogen Peroxide; Oxidation-Reduction; Antioxidants; Reactive Nitrogen Species; Nitric Oxide; Peroxisomes
PubMed: 36642282
DOI: 10.1016/j.freeradbiomed.2023.01.014 -
IUBMB Life Nov 2011This review summarizes the historical aspects of the study of peroxisome degradation in mammalian cells. Peroxisomes have diverse metabolic roles in response to... (Review)
Review
This review summarizes the historical aspects of the study of peroxisome degradation in mammalian cells. Peroxisomes have diverse metabolic roles in response to environmental changes and are degraded in a preferential manner, by comparison with cytosolic proteins. This review introduces three hypotheses on the degradation mechanisms: (a) the action of the peroxisome-specific Lon protease; (b) the membrane disruption effect of 15-lipoxygenase; and (c) autophagy that sequesters and degrades the organelles by lysosomal enzymes. Among these hypotheses, autophagy is now recognized as the most important mechanism for excess peroxisome degradation. One of the most striking characteristics of peroxisomes is that they are markedly proliferated in the liver by the administration of hypolipidemic drugs and industrial plasticizers. The effects of these substances were fully reversed after withdrawal of the substances, and most of the excess peroxisomes were selectively degraded and recovered to a normal number and size. Autophagic degradation of peroxisomes has been examined using this characteristic phenomenon. Excessive peroxisome degradation that occurs after cessation of hypolipidemic drugs has been extensively investigated biochemically and morphologically. The evidence shows that the degradation of excess peroxisomes and peroxisomal enzymes is inhibited by 3-methyladenine (3-MA), a specific inhibitor of autophagy. Furthermore, in liver-specific autophagy-deficient mice, rapid removal of peroxisomes was exclusively impaired, and degradation of peroxisomal enzymes was not detected. Thus, the significant contribution of autophagic machinery to peroxisomal degradation in mammals was confirmed. However, the important question of the mechanism for the selective recognition of peroxisomes by autophagosomes remains to be fully elucidated.
Topics: Animals; Arachidonate 15-Lipoxygenase; Autophagy; Cells, Cultured; Half-Life; Humans; Hypolipidemic Agents; Leupeptins; Mammals; Peroxisomes; Protease La; Ubiquitination
PubMed: 21990012
DOI: 10.1002/iub.537 -
Free Radical Biology & Medicine Sep 2023Reduced (NADH) and oxidized (NAD) nicotinamide adenine dinucleotides are ubiquitous hydride-donating/accepting cofactors that are essential for cellular bioenergetics....
Reduced (NADH) and oxidized (NAD) nicotinamide adenine dinucleotides are ubiquitous hydride-donating/accepting cofactors that are essential for cellular bioenergetics. Peroxisomes are single-membrane-bounded organelles that are involved in multiple lipid metabolism pathways, including beta-oxidation of fatty acids, and which contain several NAD(H)-dependent enzymes. Although maintenance of NAD(H) homeostasis in peroxisomes is considered essential for peroxisomal beta-oxidation, little is known about the regulation thereof. To resolve this issue, we have developed methods to specifically measure intraperoxisomal NADH levels in human cells using peroxisome-targeted NADH biosensors. By targeted CRISPR-Cas9-mediated genome editing of human cells, we showed with these sensors that the NAD/NADH ratio in cytosol and peroxisomes are closely connected and that this crosstalk is mediated by intraperoxisomal lactate and malate dehydrogenases, generated via translational stop codon readthrough of the LDHB and MDH1 mRNAs. Our study provides evidence for the existence of two independent redox shuttle systems in human peroxisomes that regulate peroxisomal NAD/NADH homeostasis. This is the first study that shows a specific metabolic function of protein isoforms generated by translational stop codon readthrough in humans.
Topics: Humans; NAD; Codon, Terminator; Peroxisomes; Protein Biosynthesis; Oxidation-Reduction; Homeostasis
PubMed: 37355054
DOI: 10.1016/j.freeradbiomed.2023.06.020 -
Biochemical Society Transactions Oct 2015Peroxisomes are arguably the most biochemically versatile of all eukaryotic organelles. Their metabolic functions vary between different organisms, between different... (Review)
Review
Peroxisomes are arguably the most biochemically versatile of all eukaryotic organelles. Their metabolic functions vary between different organisms, between different tissue types of the same organism and even between different developmental stages or in response to changed environmental conditions. New functions for peroxisomes are still being discovered and their importance is underscored by the severe phenotypes that can arise as a result of peroxisome dysfunction. The β-oxidation pathway is central to peroxisomal metabolism, but the substrates processed are very diverse, reflecting the diversity of peroxisomes across species. Substrates for β-oxidation enter peroxisomes via ATP-binding cassette (ABC) transporters of subfamily D; (ABCD) and are activated by specific acyl CoA synthetases for further metabolism. Humans have three peroxisomal ABCD family members, which are half transporters that homodimerize and have distinct but partially overlapping substrate specificity; Saccharomyces cerevisiae has two half transporters that heterodimerize and plants have a single peroxisomal ABC transporter that is a fused heterodimer and which appears to be the single entry point into peroxisomes for a very wide variety of β-oxidation substrates. Our studies suggest that the Arabidopsis peroxisomal ABC transporter AtABCD1 accepts acyl CoA substrates, cleaves them before or during transport followed by reactivation by peroxisomal synthetases. We propose that this is a general mechanism to provide specificity to this class of transporters and by which amphipathic compounds are moved across peroxisome membranes.
Topics: ATP-Binding Cassette Transporters; Arabidopsis Proteins; Coenzyme A Ligases; Fatty Acids; Humans; Models, Molecular; Oxidation-Reduction; Peroxisomes; Protein Conformation; Saccharomyces cerevisiae Proteins
PubMed: 26517910
DOI: 10.1042/BST20150127