1
|
Chen CT, Shao Z, Fu Z. Dysfunctional peroxisomal lipid metabolisms and their ocular manifestations. Front Cell Dev Biol 2022; 10:982564. [PMID: 36187472 PMCID: PMC9524157 DOI: 10.3389/fcell.2022.982564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/17/2022] [Indexed: 11/13/2022] Open
Abstract
Retina is rich in lipids and dyslipidemia causes retinal dysfunction and eye diseases. In retina, lipids are not only important membrane component in cells and organelles but also fuel substrates for energy production. However, our current knowledge of lipid processing in the retina are very limited. Peroxisomes play a critical role in lipid homeostasis and genetic disorders with peroxisomal dysfunction have different types of ocular complications. In this review, we focus on the role of peroxisomes in lipid metabolism, including degradation and detoxification of very-long-chain fatty acids, branched-chain fatty acids, dicarboxylic acids, reactive oxygen/nitrogen species, glyoxylate, and amino acids, as well as biosynthesis of docosahexaenoic acid, plasmalogen and bile acids. We also discuss the potential contributions of peroxisomal pathways to eye health and summarize the reported cases of ocular symptoms in patients with peroxisomal disorders, corresponding to each disrupted peroxisomal pathway. We also review the cross-talk between peroxisomes and other organelles such as lysosomes, endoplasmic reticulum and mitochondria.
Collapse
Affiliation(s)
- Chuck T. Chen
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Zhuo Shao
- Post-Graduate Medical Education, University of Toronto, Toronto, ON, Canada
- Division of Clinical and Metabolic Genetics, the Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- The Genetics Program, North York General Hospital, University of Toronto, Toronto, ON, Canada
| | - Zhongjie Fu
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
- *Correspondence: Zhongjie Fu,
| |
Collapse
|
2
|
Kunze M. The type-2 peroxisomal targeting signal. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1867:118609. [PMID: 31751594 DOI: 10.1016/j.bbamcr.2019.118609] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 11/08/2019] [Accepted: 11/13/2019] [Indexed: 12/13/2022]
Abstract
The type-2 peroxisomal targeting signal (PTS2) is one of two peptide motifs destining soluble proteins for peroxisomes. This signal acts as amphiphilic α-helix exposing the side chains of all conserved residues to the same side. PTS2 motifs are recognized by a bipartite protein complex consisting of the receptor PEX7 and a co-receptor. Cargo-loaded receptor complexes are translocated across the peroxisomal membrane by a transient pore and inside peroxisomes, cargo proteins are released and processed in many, but not all species. The components of the bipartite receptor are re-exported into the cytosol by a ubiquitin-mediated and ATP-driven export mechanism. Structurally, PTS2 motifs resemble other N-terminal targeting signals, whereas the functional relation to the second peroxisomal targeting signal (PTS1) is unclear. Although only a few PTS2-carrying proteins are known in humans, subjects lacking a functional import mechanism for these proteins suffer from the severe inherited disease rhizomelic chondrodysplasia punctata.
Collapse
Affiliation(s)
- Markus Kunze
- Medical University of Vienna, Center for Brain Research, Department of Pathobiology of the Nervous System, Spitalgasse 4, 1090 Vienna, Austria.
| |
Collapse
|
3
|
Wanders RJA, Ferdinandusse S, Ebberink MS, Waterham HR. Phytanoyl-CoA Hydroxylase: A 2-Oxoglutarate-Dependent Dioxygenase Crucial for Fatty Acid Alpha-Oxidation in Humans. 2-OXOGLUTARATE-DEPENDENT OXYGENASES 2015. [DOI: 10.1039/9781782621959-00338] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Phytanoyl-CoA hydroxylase belongs to the family of 2-oxoglutarate-dependent dioxygenases and plays a crucial role in the α-oxidation of fatty acids. The complete α-oxidation pathway involves five different enzymes localized in peroxisomes. Thus far, phytanoyl-CoA hydroxylase deficiency has remained the only genetically determined inborn error of metabolism affecting the α-oxidation pathway. In this chapter we describe the current state of knowledge on fatty acid α-oxidation with special emphasis on phytanoyl-CoA hydroxylase and its deficiency in Refsum disease.
Collapse
Affiliation(s)
- Ronald J. A. Wanders
- Laboratory Genetic Metabolic Diseases, Departments of Paediatrics, Emma Children’s Hospital, and Clinical Chemistry, Academic Medical Center, University of Amsterdam Meibergdreef 9 1105 AZ Amsterdam the Netherlands
| | - Sacha Ferdinandusse
- Laboratory Genetic Metabolic Diseases, Departments of Paediatrics, Emma Children’s Hospital, and Clinical Chemistry, Academic Medical Center, University of Amsterdam Meibergdreef 9 1105 AZ Amsterdam the Netherlands
| | - Merel S. Ebberink
- Laboratory Genetic Metabolic Diseases, Departments of Paediatrics, Emma Children’s Hospital, and Clinical Chemistry, Academic Medical Center, University of Amsterdam Meibergdreef 9 1105 AZ Amsterdam the Netherlands
| | - Hans R. Waterham
- Laboratory Genetic Metabolic Diseases, Departments of Paediatrics, Emma Children’s Hospital, and Clinical Chemistry, Academic Medical Center, University of Amsterdam Meibergdreef 9 1105 AZ Amsterdam the Netherlands
| |
Collapse
|
4
|
Kundu S. Distribution and prediction of catalytic domains in 2-oxoglutarate dependent dioxygenases. BMC Res Notes 2012; 5:410. [PMID: 22862831 PMCID: PMC3475032 DOI: 10.1186/1756-0500-5-410] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 06/29/2012] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The 2-oxoglutarate dependent superfamily is a diverse group of non-haem dioxygenases, and is present in prokaryotes, eukaryotes, and archaea. The enzymes differ in substrate preference and reaction chemistry, a factor that precludes their classification by homology studies and electronic annotation schemes alone. In this work, I propose and explore the rationale of using substrates to classify structurally similar alpha-ketoglutarate dependent enzymes. FINDINGS Differential catalysis in phylogenetic clades of 2-OG dependent enzymes, is determined by the interactions of a subset of active-site amino acids. Identifying these with existing computational methods is challenging and not feasible for all proteins. A clustering protocol based on validated mechanisms of catalysis of known molecules, in tandem with group specific hidden markov model profiles is able to differentiate and sequester these enzymes. Access to this repository is by a web server that compares user defined unknown sequences to these pre-defined profiles and outputs a list of predicted catalytic domains. The server is free and is accessible at the following URL (http://comp-biol.theacms.in/H2OGpred.html). CONCLUSIONS The proposed stratification is a novel attempt at classifying and predicting 2-oxoglutarate dependent function. In addition, the server will provide researchers with a tool to compare their data to a comprehensive list of HMM profiles of catalytic domains. This work, will aid efforts by investigators to screen and characterize putative 2-OG dependent sequences. The profile database will be updated at regular intervals.
Collapse
Affiliation(s)
- Siddhartha Kundu
- Department of Biochemistry, Army College of Medical Sciences, Delhi Cantt., New Delhi 110010, India.
| |
Collapse
|
5
|
Araújo WL, Ishizaki K, Nunes-Nesi A, Tohge T, Larson TR, Krahnert I, Balbo I, Witt S, Dörmann P, Graham IA, Leaver CJ, Fernie AR. Analysis of a range of catabolic mutants provides evidence that phytanoyl-coenzyme A does not act as a substrate of the electron-transfer flavoprotein/electron-transfer flavoprotein:ubiquinone oxidoreductase complex in Arabidopsis during dark-induced senescence. PLANT PHYSIOLOGY 2011; 157:55-69. [PMID: 21788362 PMCID: PMC3221279 DOI: 10.1104/pp.111.182188] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The process of dark-induced senescence in plants is not fully understood, however, the functional involvement of an electron-transfer flavoprotein/electron-transfer flavoprotein:ubiquinone oxidoreductase (ETF/ETFQO), has been demonstrated. Recent studies have revealed that the enzymes isovaleryl-coenzyme A (CoA) dehydrogenase and 2-hydroxyglutarate dehydrogenase act as important electron donors to this complex. In addition both enzymes play a role in the breakdown of cellular carbon storage reserves with isovaleryl-CoA dehydrogenase being involved in degradation of the branched-chain amino acids, phytol, and lysine while 2-hydroxyglutarate dehydrogenase is exclusively involved in lysine degradation. Given that the chlorophyll breakdown intermediate phytanoyl-CoA accumulates dramatically both in knockout mutants of the ETF/ETFQO complex and of isovaleryl-CoA dehydrogenase following growth in extended dark periods we have investigated the direct importance of chlorophyll breakdown for the supply of carbon and electrons during this process. For this purpose we isolated three independent Arabidopsis (Arabidopsis thaliana) knockout mutants of phytanoyl-CoA 2-hydroxylase and grew them under the same extended darkness regime as previously used. Despite the fact that these mutants accumulated phytanoyl-CoA and also 2-hydroxyglutarate they exhibited no morphological changes in comparison to the other mutants previously characterized. These results are consistent with a single entry point of phytol breakdown into the ETF/ETFQO system and furthermore suggest that phytol is not primarily metabolized by this pathway. Furthermore analysis of isovaleryl-CoA dehydrogenase/2-hydroxyglutarate dehydrogenase double mutants generated here suggest that these two enzymes essentially account for the entire electron input via the ETF complex.
Collapse
|
6
|
Wanders RJA, Komen J, Ferdinandusse S. Phytanic acid metabolism in health and disease. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1811:498-507. [PMID: 21683154 DOI: 10.1016/j.bbalip.2011.06.006] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 05/25/2011] [Accepted: 06/01/2011] [Indexed: 10/18/2022]
Abstract
Phytanic acid (3,7,11,15-tetramethylhexadecanoic acid) is a branched-chain fatty acid which cannot be beta-oxidized due to the presence of the first methyl group at the 3-position. Instead, phytanic acid undergoes alpha-oxidation to produce pristanic acid (2,6,10,14-tetramethylpentadecanoic acid) plus CO(2). Pristanic acid is a 2-methyl branched-chain fatty acid which can undergo beta-oxidation via sequential cycles of beta-oxidation in peroxisomes and mitochondria. The mechanism of alpha-oxidation has been resolved in recent years as reviewed in this paper, although some of the individual enzymatic steps remain to be identified. Furthermore, much has been learned in recent years about the permeability properties of the peroxisomal membrane with important consequences for the alpha-oxidation process. Finally, we present new data on the omega-oxidation of phytanic acid making use of a recently generated mouse model for Refsum disease in which the gene encoding phytanoyl-CoA 2-hydroxylase has been disrupted.
Collapse
Affiliation(s)
- Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
| | | | | |
Collapse
|
7
|
Luo B, Norris C, Bolstad ESD, Knecht DA, Grant DF. Protein quaternary structure and expression levels contribute to peroxisomal-targeting-sequence-1-mediated peroxisomal import of human soluble epoxide hydrolase. J Mol Biol 2008; 380:31-41. [PMID: 18513744 DOI: 10.1016/j.jmb.2008.04.064] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Revised: 04/23/2008] [Accepted: 04/28/2008] [Indexed: 01/26/2023]
Abstract
The peroxisomal targeting sequence 1 (PTS1) is a consensus tripeptide 1 (S/C/A)(K/R/H)(L/M) that is found at the C-terminus of most peroxisomal proteins. However, the only known mammalian protein containing a terminal methionine PTS1 (SKM), human soluble epoxide hydrolase (hsEH), shows both peroxisomal and cytosolic localizations in vivo. Mechanisms regulating the subcellular localization of hsEH thus remain unclear. Here we utilized green fluorescent protein-hsEH fusion constructs to study the peroxisomal targeting of hsEH in transiently and stably transfected Chinese hamster ovary cells. Our results suggest that the peroxisomal import of hsEH is regulated by three factors. First, we show that SKM is required, but not sufficient, for peroxisomal import. Second, by manipulating protein expression levels, we show that SKM mediates peroxisomal import of wild-type hsEH only when expression levels are high. Third, we show that amino acid modifications that decrease subunit oligomerization and presumably enhance accessibility of the SKM motif confer peroxisomal targeting even at low protein expression levels. We conclude that, in hsEH, SKM is a necessary but inefficient and context-dependent PTS1. Peroxisomal import occurs when expression levels are high or when the SKM motif is accessible. These results provide a mechanistic basis for understanding the cell-specific and tissue-specific localization of hsEH in vivo.
Collapse
Affiliation(s)
- Beibei Luo
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT 06269, USA
| | | | | | | | | |
Collapse
|
8
|
Khan Z, Michalopoulos GK, Stolz DB. Peroxisomal localization of hypoxia-inducible factors and hypoxia-inducible factor regulatory hydroxylases in primary rat hepatocytes exposed to hypoxia-reoxygenation. THE AMERICAN JOURNAL OF PATHOLOGY 2006; 169:1251-69. [PMID: 17003483 PMCID: PMC1698853 DOI: 10.2353/ajpath.2006.060360] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Many signals involved in pathophysiology are controlled by hypoxia-inducible factors (HIFs), transcription factors that induce expression of hypoxia-responsive genes. HIFs are post-translationally regulated by a family of O2-dependent HIF hydroxylases: four prolyl 4-hydroxylases and an asparaginyl hydroxylase. Most of these enzymes are abundant in resting liver, which is itself unique because of its physiological O2 gradient, and they can exist in both nuclear and cytoplasmic pools. In this study, we analyzed the cellular localization of endogenous HIFs and their regulatory hydroxylases in primary rat hepatocytes cultured under hypoxia-reoxygenation conditions. In hepatocytes, hypoxia targeted HIF-1alpha to the peroxisome, rather than the nucleus, where it co-localized with von Hippel-Lindau tumor suppressor protein and the HIF hydroxylases. Confocal immunofluorescence microscopy demonstrated that the HIF hydroxylases translocated from the nucleus to the cytoplasm in response to hypoxia, with increased accumulation in peroxisomes on reoxygenation. These results were confirmed via immunotransmission electron microscopy and Western blotting. Surprisingly, in resting liver tissue, perivenous localization of the HIF hydroxylases was observed, consistent with areas of low pO2. In conclusion, these studies establish the peroxisome as a highly relevant site of subcellular localization and function for the endogenous HIF pathway in hepatocytes.
Collapse
Affiliation(s)
- Zahida Khan
- University of Pittsburgh School of Medicine, Cellular and Molecular Pathology, Pittsburgh, PA 15261, USA
| | | | | |
Collapse
|
9
|
Matsumoto K, Imagawa S, Obara N, Suzuki N, Takahashi S, Nagasawa T, Yamamoto M. 2-oxoglutarate downregulates expression of vascular endothelial growth factor and erythropoietin through decreasing hypoxia-inducible factor-1α and inhibits angiogenesis. J Cell Physiol 2006; 209:333-40. [PMID: 16883594 DOI: 10.1002/jcp.20733] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In oxygenated cells, hypoxia-inducible factor-1 (HIF-1) alpha subunits are rapidly degraded by a mechanism that involves ubiquitination by the von Hippel-Lindau tumor suppressor E3 ligase complex using 2-oxoglutarate as a substrate. We examined the effect of 2-oxoglutarate on the production of erythropoietin and vascular endothelial growth factor (VEGF). The expression of erythropoietin and VEGF protein were dose-dependently downregulated in Hep3B cells by the addition of 2-oxoglutarate. The promoter activity of VEGF-luciferase was dose-dependently downregulated by the addition of 2-oxoglutarate. Gel mobility shift assays revealed that the addition of 2-oxoglutarate dose-dependently inhibited HIF-1 binding activity, but did not affect GATA binding activity. Western blot analysis revealed that 2-oxoglutarate dose-dependently inhibited the HIF-1alpha protein level in Hep3B cells in hypoxic conditions. However, MG132 (the proteasome inhibitor) rescued the inhibition of HIF-1alpha protein expression by 2-oxoglutarate. Furthermore, under hypoxic conditions, 2-oxoglutarate dose-dependently inhibited tube formation in in vitro angiogenesis assays. These results indicate that 2-oxoglutarate treatment may be useful for the inhibition of angiogenesis.
Collapse
Affiliation(s)
- Ken Matsumoto
- Department of Clinical and Experimental Hematology, Doctoral Program in Advanced Biomedical Applications, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | | | | | | | | | | | | |
Collapse
|
10
|
Gloerich J, van Vlies N, Jansen GA, Denis S, Ruiter JPN, van Werkhoven MA, Duran M, Vaz FM, Wanders RJA, Ferdinandusse S. A phytol-enriched diet induces changes in fatty acid metabolism in mice both via PPARalpha-dependent and -independent pathways. J Lipid Res 2005; 46:716-26. [PMID: 15654129 DOI: 10.1194/jlr.m400337-jlr200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Branched-chain fatty acids (such as phytanic and pristanic acid) are ligands for the nuclear hormone receptor peroxisome proliferator-activated receptor alpha (PPARalpha) in vitro. To investigate the effects of these physiological compounds in vivo, wild-type and PPARalpha-deficient (PPARalpha-/-) mice were fed a phytol-enriched diet. This resulted in increased plasma and liver levels of the phytol metabolites phytanic and pristanic acid. In wild-type mice, plasma fatty acid levels decreased after phytol feeding, whereas in PPARalpha-/- mice, the already elevated fatty acid levels increased. In addition, PPARalpha-/- mice were found to be carnitine deficient in both plasma and liver. Dietary phytol increased liver free carnitine in wild-type animals but not in PPARalpha-/- mice. Investigation of carnitine biosynthesis revealed that PPARalpha is likely involved in the regulation of carnitine homeostasis. Furthermore, phytol feeding resulted in a PPARalpha-dependent induction of various peroxisomal and mitochondrial beta-oxidation enzymes. In addition, a PPARalpha-independent induction of catalase, phytanoyl-CoA hydroxylase, carnitine octanoyltransferase, peroxisomal 3-ketoacyl-CoA thiolase, and straight-chain acyl-CoA oxidase was observed. In conclusion, branched-chain fatty acids are physiologically relevant ligands of PPARalpha in mice. These findings are especially relevant for disorders in which branched-chain fatty acids accumulate, such as Refsum disease and peroxisome biogenesis disorders.
Collapse
Affiliation(s)
- J Gloerich
- University of Amsterdam, Academic Medical Center, Departments of Clinical Chemistry and Pediatrics, Laboratory for Genetic Metabolic Diseases, 1100 DE Amsterdam, The Netherlands
| | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Ding Y, Bojja RS, Du L. Fum3p, a 2-ketoglutarate-dependent dioxygenase required for C-5 hydroxylation of fumonisins in Fusarium verticillioides. Appl Environ Microbiol 2004; 70:1931-4. [PMID: 15066782 PMCID: PMC383085 DOI: 10.1128/aem.70.4.1931-1934.2004] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fumonisins are polyketide-derived mycotoxins produced by several agriculturally important Fusarium species. The B series fumonisins, FB(1), FB(2), FB(3), and FB(4), are fumonisins produced by wild-type Fusarium verticillioides strains, differing in the number and location of hydroxyl groups attached to the carbon backbone. We characterized the protein encoded by FUM3, a gene in the fumonisin biosynthetic gene cluster. The 33-kDa FUM3 protein (Fum3p) was heterologously expressed and purified from Saccharomyces cerevisiae. Yeast cells expressing the Fum3p converted FB(3) to FB(1), indicating that Fum3p catalyzes the C-5 hydroxylation of fumonisins. This result was verified by assaying the activity of Fum3p purified from yeast cells. The C-5 hydroxylase activity of purified Fum3p required 2-ketoglutarate, Fe(2+), ascorbic acid, and catalase, all of which are required for 2-ketoglutarate-dependent dioxygenases. The protein also contains two His motifs that are highly conserved in this family of dioxygenases. Thus, Fum3p is a 2-ketoglutarate-dependent dioxygenase required for the addition of the C-5 hydroxyl group of fumonisins.
Collapse
Affiliation(s)
- Yousong Ding
- Chemistry Department, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0304, USA
| | | | | |
Collapse
|
12
|
Su X, Han X, Yang J, Mancuso DJ, Chen J, Bickel PE, Gross RW. Sequential ordered fatty acid alpha oxidation and Delta9 desaturation are major determinants of lipid storage and utilization in differentiating adipocytes. Biochemistry 2004; 43:5033-44. [PMID: 15109262 DOI: 10.1021/bi035867z] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herein, we exploit the power of global lipidomics to identify the critical role of peroxisomal processing of fatty acids in adipocyte lipid storage and metabolism. Remarkably, 3T3-L1 differentiating adipocytes rapidly acquired the ability to alpha oxidize unbranched fatty acids, which is manifested in the accumulation of odd chain length unbranched fatty acids in all major lipid classes. Moreover, in differentiating adipocytes, unsaturated odd chain length fatty acids in TAG molecular species contained exclusively Delta9 olefinic linkages. Unsaturated fatty acids (e.g., oleic and palmitoleic acids) were not subject to alpha oxidation, resulting in the absence of Delta8 unsaturated odd chain length fatty acids. This highly selective substrate utilization resulted in the obligatory sequential ordering of alpha oxidation prior to Delta9 desaturation. On the basis of these results, a putative type 2 peroxisomal localization sequence was identified at the N-terminus of mouse stearoyl-CoA desaturase I (SCD I) comprised of (30)KVKTVPLHL(38). Kinetic analysis demonstrated that the rate of alpha oxidation of exogenously administered [9,10-(3)H]palmitic acid increased 4-fold during differentiation. Similarly, quantitative PCR demonstrated a 4-fold increase in phytanoyl-CoA alpha hydroxylase (PAHX) and fatty acyl-CoA oxidase (FACO) mRNA levels during differentiation. Collectively, these results underscore the role of peroxisomal fatty acid processing as an important determinant of the metabolic fate of fatty acids in the differentiating adipocyte.
Collapse
Affiliation(s)
- Xiong Su
- Department of Chemistry, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | | | | | | | | | | | | |
Collapse
|
13
|
Wanders RJA, Jansen GA, Lloyd MD. Phytanic acid alpha-oxidation, new insights into an old problem: a review. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1631:119-35. [PMID: 12633678 DOI: 10.1016/s1388-1981(03)00003-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Phytanic acid (3,7,10,14-tetramethylhexadecanoic acid) is a branched-chain fatty acid which is known to accumulate in a number of different genetic diseases including Refsum disease. Due to the presence of a methyl-group at the 3-position, phytanic acid and other 3-methyl fatty acids can not undergo beta-oxidation but are first subjected to fatty acid alpha-oxidation in which the terminal carboxyl-group is released as CO(2). The mechanism of alpha-oxidation has long remained obscure but has been resolved in recent years. Furthermore, peroxisomes have been found to play an indispensable role in fatty acid alpha-oxidation, and the complete alpha-oxidation machinery is probably localized in peroxisomes. This Review describes the current state of knowledge about fatty acid alpha-oxidation in mammals with particular emphasis on the mechanism involved and the enzymology of the pathway.
Collapse
Affiliation(s)
- Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Department of Pediatrics/Emma Children's Hospital and Clinical Chemistry, Academic Medical Centre, University Hospital Amsterdam, Room F0-224, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands.
| | | | | |
Collapse
|
14
|
Jansen GA, van den Brink DM, Ofman R, Draghici O, Dacremont G, Wanders RJ. Identification of pristanal dehydrogenase activity in peroxisomes: conclusive evidence that the complete phytanic acid alpha-oxidation pathway is localized in peroxisomes. Biochem Biophys Res Commun 2001; 283:674-9. [PMID: 11341778 DOI: 10.1006/bbrc.2001.4835] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phytanic acid (3,7,11,15-tetramethylhexadecanoic acid) is a branched-chain fatty acid which, due to the methyl-group at the 3-position, can not undergo beta-oxidation unless the terminal carboxyl-group is removed by alpha-oxidation. The structure of the phytanic acid alpha-oxidation machinery in terms of the reactions involved, has been resolved in recent years and includes a series of four reactions: (1) activation of phytanic acid to phytanoyl-CoA, (2) hydroxylation of phytanoyl-CoA to 2-hydroxyphytanoyl-CoA, (3) cleavage of 2-hydroxyphytanoyl-CoA to pristanal and formyl-CoA, and (4) oxidation of pristanal to pristanic acid. The subcellular localization of the enzymes involved has remained enigmatic, with the exception of phytanoyl-CoA hydroxylase and 2-hydroxyphytanoyl-CoA lyase which are both localized in peroxisomes. The oxidation of pristanal to pristanic acid has been claimed to be catalysed by the microsomal aldehyde dehydrogenase FALDH encoded by the ALDH10-gene. Making use of mutant fibroblasts deficient in FALDH activity, we show that phytanic acid alpha-oxidation is completely normal in these cells. Furthermore, we show that pristanal dehydrogenase activity is not fully deficient in FALDH-deficient cells, implying the existence of one or more additional aldehyde dehydrogenases reacting with pristanal. Using subcellular localization studies, we now show that peroxisomes contain pristanal dehydrogenase activity which leads us to conclude that the complete phytanic acid alpha-oxidation pathway is localized in peroxisomes.
Collapse
Affiliation(s)
- G A Jansen
- Department of Clinical Chemistry, Department of Pediatrics, University of Amsterdam, Academic Medical Centre, Emma Children's Hospital, Meibergdreef 9, Amsterdam, 1105 AZ, The Netherlands
| | | | | | | | | | | |
Collapse
|
15
|
Jaakkola P, Mole DR, Tian YM, Wilson MI, Gielbert J, Gaskell SJ, von Kriegsheim A, Hebestreit HF, Mukherji M, Schofield CJ, Maxwell PH, Pugh CW, Ratcliffe PJ. Targeting of HIF-alpha to the von Hippel-Lindau ubiquitylation complex by O2-regulated prolyl hydroxylation. Science 2001; 292:468-72. [PMID: 11292861 DOI: 10.1126/science.1059796] [Citation(s) in RCA: 4154] [Impact Index Per Article: 180.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hypoxia-inducible factor (HIF) is a transcriptional complex that plays a central role in the regulation of gene expression by oxygen. In oxygenated and iron replete cells, HIF-alpha subunits are rapidly destroyed by a mechanism that involves ubiquitylation by the von Hippel-Lindau tumor suppressor (pVHL) E3 ligase complex. This process is suppressed by hypoxia and iron chelation, allowing transcriptional activation. Here we show that the interaction between human pVHL and a specific domain of the HIF-1alpha subunit is regulated through hydroxylation of a proline residue (HIF-1alpha P564) by an enzyme we have termed HIF-alpha prolyl-hydroxylase (HIF-PH). An absolute requirement for dioxygen as a cosubstrate and iron as cofactor suggests that HIF-PH functions directly as a cellular oxygen sensor.
Collapse
Affiliation(s)
- P Jaakkola
- The Henry Wellcome Building of Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Zomer AW, van der Burg B, Jansen GA, Wanders RJ, Poll-The BT, van der Saag PT. Pristanic acid and phytanic acid: naturally occurring ligands for the nuclear receptor peroxisome proliferator-activated receptor α. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)31973-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|