The rat liver peroxisomal membrane forms a permeability barrier for cofactors but not for small metabolites in vitro

Antonenkov, Vasily D.; Sormunen, Raija; Hiltunen, J. Kalervo

doi:10.1242/jcs.01485

Cited by 75 publications

(61 citation statements)

References 41 publications

(59 reference statements)

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“…Extending this view, the supply and availability of CoASH as another regulating factor should be mentioned, because for every chain-shortening event another coenzyme A is consumed. Peroxisomes house an internal pool of CoASH, which cannot diffuse across the organellar membrane (56,57). Horie et al (58) have found an increase in free CoASH upon fibrate stimulation, whereas acyl-bound CoA remained stable, concluding that the free CoASH concentration is a positive regulating factor in the enhancement of the peroxisomal fatty acid oxidation system.…”

Section: Discussionmentioning

confidence: 99%

Rat Liver Peroxisomes after Fibrate Treatment

Islinger

Lüers²,

et al. 2007

Journal of Biological Chemistry

108

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Fibrates are known to induce peroxisome proliferation and the expression of peroxisomal ␤-oxidation enzymes. To analyze fibrate-induced changes of complex metabolic networks, we have compared the proteome of rat liver peroxisomes from control and bezafibrate-treated rats. Highly purified peroxisomes were subfractionated, and the proteins of the matrix, peripheral, and integral membrane subfractions thus obtained were analyzed by matrix-assisted laser desorption ionization time-offlight/time-of-flight mass spectrometry after labeling of tryptic peptides with the iTRAQ reagent. By means of this quantitative technique, we were able to identify 134 individual proteins, covering most of the known peroxisomal proteome. Ten predicted new open reading frames were verified by cDNA cloning, and seven of them could be localized to peroxisomes by immunocytochemistry. Moreover, quantitative mass spectrometry substantiated the induction of most of the known peroxisome proliferator-activated receptor ␣-regulated peroxisomal proteins upon treatment with bezafibrate, documenting the suitability of the iTRAQ procedure in larger scale experiments. However, not all proteins reacted to a similar extent but exerted a fibratespecific induction scheme showing the variability of peroxisome proliferator-activated receptor ␣-transmitted responses to specific ligands. In view of our data, rat hepatic peroxisomes are apparently not specialized to sequester very long chain fatty acids (C22-C26) but rather metabolize preferentially long chain fatty acids (C16 -18).Peroxisomes, often described as multipurpose organelles, are involved in numerous biochemical pathways of lipid and peroxide metabolism. The existence of more than 15 peroxisomal inherited diseases like the Zellweger syndrome or X-linked adrenoleukodystrophy, which are often lethal, emphasizes the vital importance of these organelles (1-3). Cells are able to remodel the protein composition of their peroxisomes and to adjust the number of these organelles in response to physiological or environmental stimuli to cope with the metabolic needs. Consequently, peroxisomes are regarded as highly modular organelles, with different protein composition depending on the metabolic function or cell type. Fibrates, used as hypolipidemic drugs, induce both the proliferation of peroxisomes as well as the ␤-oxidation of fatty acids (4). These alterations of the metabolic functions of peroxisomes are accompanied by changes of proteins involved in the biogenesis of the organelles as well as in enzymes for the breakdown of fatty acids (5, 6). Several investigators in the past have used fibrate-induced peroxisome proliferation as a model to analyze selected aspects of peroxisome biogenesis or lipid metabolism, using techniques like Western blotting, enzyme assays, immunocytochemistry, Northern blotting, or in situ hybridization (6 -11). However, complex rearrangements of the entire peroxisomal proteome could not be analyzed with these techniques.In this respect, mass spectrometry represents a straightfo...

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Section: Discussionmentioning

confidence: 99%

Rat Liver Peroxisomes after Fibrate Treatment

Islinger

Lüers²,

et al. 2007

Journal of Biological Chemistry

108

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“…The screen performed by Van Roermund et al (52), aimed at isolation of S. cerevisiae mutants affected in acetyl unit transport from peroxisomes to mitochondria, failed to identify a peroxisomal acyl/acetyl-carnitine carrier. A possible explanation for this observation is that recent evidence suggests that the peroxisomal membrane contains pore-forming proteins that enable transfer of small molecules (with molecular masses of less than 400 Da) across the membrane (1,13,38,40). This finding may suggest that a small molecule like acetyl-carnitine does not require a specific transporter but can pass the peroxisomal membrane through a poreforming channel.…”

Section: Carnitine Transportersmentioning

confidence: 97%

“…Because of its amphiphilic nature and bulkiness, acetyl-CoA cannot freely cross biological membranes (1,40,51). Two major pathways that allow the export of acetyl units generated by peroxisomal ␤-oxidation have been identified: (i) a carnitine shuttle in which carnitine-acetyltransferases reversibly link the carrier carnitine to the acetyl unit of acetyl-CoA, forming acetyl-carnitine that can cross the membrane, and (ii) through the action of peroxisomal citrate synthase that catalyzes the condensation of acetyl-CoA with oxaloacetate to form citrate, which can be transported over the peroxisomal membrane.…”

Section: Carnitine-dependent and -Independent Transport Of Acetyl Unitsmentioning

confidence: 99%

Intracellular Acetyl Unit Transport in Fungal Carbon Metabolism

2010

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Acetyl coenzyme A (acetyl-CoA) is a central metabolite in carbon and energy metabolism. Because of its amphiphilic nature and bulkiness, acetyl-CoA cannot readily traverse biological membranes. In fungi, two systems for acetyl unit transport have been identified: a shuttle dependent on the carrier carnitine and a (peroxisomal) citrate synthase-dependent pathway. In the carnitine-dependent pathway, carnitine acetyltransferases exchange the CoA group of acetyl-CoA for carnitine, thereby forming acetyl-carnitine, which can be transported between subcellular compartments. Citrate synthase catalyzes the condensation of oxaloacetate and acetyl-CoA to form citrate that can be transported over the membrane. Since essential metabolic pathways such as fatty acid ␤-oxidation, the tricarboxylic acid (TCA) cycle, and the glyoxylate cycle are physically separated into different organelles, shuttling of acetyl units is essential for growth of fungal species on various carbon sources such as fatty acids, ethanol, acetate, or citrate. In this review we summarize the current knowledge on the different systems of acetyl transport that are operational during alternative carbon metabolism, with special focus on two fungal species: Saccharomyces cerevisiae and Candida albicans.

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“…While cytosolic/ nuclear and mitochondrial matrix contents have been measured, the presence of NAD in other compartments has not been established, at least in part because of the analytical difficulties. The activities of NAD-dependent dehydrogenases attest the presence of this nucleotide in peroxisomes, while the membranes of these organelles appear impermeable to NAD [12].…”

Section: Introductionmentioning

confidence: 97%

Visualization of subcellular NAD pools and intra-organellar protein localization by poly-ADP-ribose formation

Dölle

Niere

Lohndal

et al. 2009

Cell. Mol. Life Sci.

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Poly-ADP-ribose polymerases (PARPs) use NAD(+) as substrate to generate polymers of ADP-ribose. We targeted the catalytic domain of human PARP1 as molecular NAD(+) detector into cellular organelles. Immunochemical detection of polymers demonstrated distinct subcellular NAD(+) pools in mitochondria, peroxisomes and, surprisingly, in the endoplasmic reticulum and the Golgi complex. Polymers did not accumulate within the mitochondrial intermembrane space or the cytosol. We demonstrate the suitability of this compartment-specific NAD(+) and poly-ADP-ribose turnover to establish intra-organellar protein localization. For overexpressed proteins, genetically endowed with PARP activity, detection of polymers indicates segregation from the cytosol and consequently intra-organellar residence. In mitochondria, polymer build-up reveals matrix localization of the PARP fusion protein. Compared to presently used fusion tags for subcellular protein localization, these are substantial improvements in resolution. We thus established a novel molecular tool applicable for studies of subcellular NAD metabolism and protein localization.

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The rat liver peroxisomal membrane forms a permeability barrier for cofactors but not for small metabolites in vitro

Cited by 75 publications

References 41 publications

Rat Liver Peroxisomes after Fibrate Treatment

Rat Liver Peroxisomes after Fibrate Treatment

Intracellular Acetyl Unit Transport in Fungal Carbon Metabolism

Visualization of subcellular NAD pools and intra-organellar protein localization by poly-ADP-ribose formation

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