Implication of a peroxisomal enzyme in the catabolism of glutaryl-CoA.
Ontology highlight
ABSTRACT:
SUBMITTER: Vamecq J
PROVIDER: S-EPMC1144021 | biostudies-other | 1984 Jul
REPOSITORIES: biostudies-other
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Project description:Peroxisomes carry out many essential lipid metabolic functions. Nearly all of these functions require that an acyl group-either a fatty acid or the acyl side chain of a steroid derivative-be thioesterified to coenzyme A (CoA) for subsequent reactions to proceed. This thioesterification, or "activation", reaction, catalyzed by enzymes belonging to the acyl-CoA synthetase family, is thus central to cellular lipid metabolism. However, despite our rather thorough understanding of peroxisomal metabolic pathways, surprisingly little is known about the specific peroxisomal acyl-CoA synthetases that participate in these pathways. Of the 26 acyl-CoA synthetases encoded by the human and mouse genomes, only a few have been reported to be peroxisomal, including ACSL4, SLC27A2, and SLC27A4. In this review, we briefly describe the primary peroxisomal lipid metabolic pathways in which fatty acyl-CoAs participate. Then, we examine the evidence for presence and functions of acyl-CoA synthetases in peroxisomes, much of which was obtained before the existence of multiple acyl-CoA synthetase isoenzymes was known. Finally, we discuss the role(s) of peroxisome-specific acyl-CoA synthetase isoforms in lipid metabolism.
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Project description:Metabolic reprogramming provides transformed cells with proliferative and/or survival advantages. However, capitalizing on this therapeutically has been only moderately successful due to the relatively small magnitude of these differences and because cancers may re-program their metabolism to evade metabolic pathway inhibition. Mice lacking the peroxisomal bi-functional enzyme enoyl-CoA hydratase/3-hydroxyacyl CoA dehydrogenase (Ehhadh) and supplemented with the 12-carbon fatty acid lauric acid (C12) accumulate dodecanedioic acid (DDDA), a toxic C12 metabolite that causes hepatocyte necrosis and acute liver failure. In a murine model of pediatric hepatoblastoma (HB), down-regulation of Ehhadh also occurs in combination with a more general suppression of mitochondrial β- and peroxisomal ω-fatty acid oxidation (FAO) pathways. HB-bearing mice provided with C12 and/or DDDA-supplemented diets survived significantly longer than those on standard diets. The tumors also developed massive necrosis in response to short-term DDDA supplementation. Reduced Ehhadh was noted in murine hepatocellular carcinomas (HCCs) and in substantial subsets of human cancers, including HCCs. Acquired DDDA resistance was not associated with Ehhadh re-expression but was associated with 129 transcript differences ~90% of which were down-regulated in DDDA-resistant tumors and ~two-thirds of which correlated with survival in several human cancers. These transcripts often encoded components of the extracellular matrix suggesting that DDDA resistance arises from its reduced intracellular transport. Our results demonstrate the feasibility of a metabolic intervention that is non-toxic, inexpensive and likely compatible with traditional therapies. C12 and/or DDDA-containing diets could potentially be used to supplement other treatments or as alternative therapeutic choices.
2021-03-23 | GSE156545 | GEO
Project description:There are three human enzymes with HMG-CoA lyase activity that are able to synthesize ketone bodies in different subcellular compartments. The mitochondrial HMG-CoA lyase was the first to be described, and catalyzes the cleavage of 3-hydroxy-3-methylglutaryl CoA to acetoacetate and acetyl-CoA, the common final step in ketogenesis and leucine catabolism. This protein is mainly expressed in the liver and its function is metabolic, since it produces ketone bodies as energetic fuels when glucose levels are low. Another isoform is encoded by the same gene for the mitochondrial HMG-CoA lyase (HMGCL), but it is located in peroxisomes. The last HMG-CoA lyase to be described is encoded by a different gene, HMGCLL1, and is located in the cytosolic side of the endoplasmic reticulum membrane. Some activity assays and tissue distribution of this enzyme have shown the brain and lung as key tissues for studying its function. Although the roles of the peroxisomal and cytosolic HMG-CoA lyases remain unknown, recent studies highlight the role of ketone bodies in metabolic remodeling, homeostasis, and signaling, providing new insights into the molecular and cellular function of these enzymes.
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Project description:FKBP52 (FKBP59, FKBP4) is a "macro" immunophilin that, although sharing high structural and functional homologies in its amino-terminal domain with FKBP12 (FKBP1), does not have immunosuppressant activity when complexed with FK506, unlike FKBP12. To investigate the physiological function of FKBP52, we used the yeast two-hybrid system as an approach to find its potential protein partners and, from that, its cellular role. This methodology, which already has allowed us to find the FK506-binding protein (FKBP)-associated protein FAP48, also led to the detection of another FKBP-associated protein. Determination of the sequence of this protein permitted its identification as phytanoyl-CoA alpha-hydroxylase (PAHX), a peroxisomal enzyme that so far was unknown as an FKBP-associated protein. Inactivation of this enzyme is responsible for Refsum disease in humans. The protein also corresponds to the mouse protein LN1, which could be involved in the progress of lupus nephritis. We show here that PAHX has the physical capacity to interact with the FKBP12-like domain of FKBP52, but not with FKBP12, suggesting that it is a particular and specific target of FKBP52. Whereas the binding of calcineurin to FKBP12 is potentiated by FK506, the specific association of PAHX and FKBP52 is maintained in the presence of FK506. This observation suggests that PAHX is a serious candidate for studying the cellular signaling pathway(s) involving FKBP52 in the presence of immunosuppressant drugs.
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Project description:Human ABC transporters ABCD1-3 are all localized on the peroxisomal membrane and participate in the β-oxidation of fatty acyl-CoAs, but they differ from each other in substrate specificity. The transport of branched-chain fatty acids from cytosol to peroxisome is specifically driven by ABCD3, dysfunction of which causes severe liver diseases such as hepatosplenomegaly. Here we report two cryogenic electron microscopy (cryo-EM) structures of ABCD3 bound to phytanoyl-CoA and ATP at resolutions of 2.9 Å and 3.2 Å, respectively. A pair of phytanoyl-CoA molecules were observed in ABCD3, each binding to one transmembrane domain (TMD), which is distinct from our previously reported structure of ABCD1, where each fatty acyl-CoA molecule strongly crosslinks two TMDs. Upon ATP binding, ABCD3 exhibits a conformation that is open towards the peroxisomal matrix, leaving two extra densities corresponding to two CoA molecules deeply embedded in the translocation cavity. Structural analysis combined with substrate-stimulated ATPase activity assays indicated that the present structures might represent two states of ABCD3 in the transport cycle. These findings advance our understanding of fatty acid oxidation and the molecular pathology of related diseases.
| S-EPMC11369193 | biostudies-literature
Project description:As a key intracellular metabolite, acetyl-coenzyme A (acetyl-CoA) plays a major role in various metabolic pathways that link anabolism and catabolism. In the yeast Saccharomyces cerevisiae, acetyl-CoA involving metabolism is compartmentalized, and may vary with the nutrient supply of a cell. Membranes separating intracellular compartments are impermeable to acetyl-CoA and no direct transport between the compartments occurs. Thus, without carnitine supply the glyoxylate shunt is the sole possible route for transferring acetyl-CoA from the cytosol or the peroxisomes into the mitochondria. Here, we investigate the physiological profiling of different deletion mutants of ACS1, ACS2, CIT2 and MLS1 individually or in combination under alternative carbon sources, and study how various mutations alter carbon distribution. Based on our results a detailed model of carbon distribution about cytosolic and peroxisomal acetyl-CoA metabolism in yeast is suggested. This will be useful to further develop yeast as a cell factory for the biosynthesis of acetyl-CoA-derived products.
| S-EPMC3411639 | biostudies-literature
Project description:Metabolic reprogramming provides transformed cells with proliferative and/or survival advantages. Capitalizing on this therapeutically, however, has been only moderately successful because of the relatively small magnitude of these differences and because cancers may further adapt their metabolism to evade metabolic pathway inhibition. Mice lacking the peroxisomal bifunctional enzyme enoyl-CoA hydratase/3-hydroxyacyl CoA dehydrogenase (Ehhadh) and supplemented with the 12-carbon fatty acid lauric acid (C12) accumulate the toxic metabolite dodecanedioic acid (DDDA), which causes acute hepatocyte necrosis and liver failure. We noted that, in a murine model of pediatric hepatoblastoma (HB) and in primary human HBs, downregulation of Ehhadh occurs in association with the suppression of mitochondrial β- and endosomal/peroxisomal ω-fatty acid oxidation pathways. This suggested that HBs might be more susceptible than normal liver tissue to C12 dietary intervention. Indeed, HB-bearing mice provided with C12- and/or DDDA-supplemented diets survived significantly longer than those on standard diets. In addition, larger tumors developed massive necrosis following short-term DDDA administration. In some HBs, the eventual development of DDDA resistance was associated with 129 transcript differences, ∼90% of which were downregulated, and approximately two-thirds of which correlated with survival in numerous human cancers. These transcripts often encoded extracellular matrix components, suggesting that DDDA resistance arises from reduced Ehhadh uptake. Lower Ehhadh expression was also noted in murine hepatocellular carcinomas and in subsets of certain human cancers, supporting the likely generality of these results. Our results demonstrate the feasibility of C12 or DDDA dietary supplementation that is nontoxic, inexpensive, and likely compatible with more standard chemotherapies.
| S-EPMC7948956 | biostudies-literature
Project description:The peroxisomal enzyme acyl-CoA oxidase is localized in the 'dense-tubular-system-enriched fraction', probably identical with the endoplasmic reticulum, in human blood platelets. This localization is strongly different from the localization of catalase which seems to be a cytosolic enzyme, in agreement with Marcus, Zucker-Franklin, Safir & Ullman [(1966) J. Clin. Invest. 45, 14-28]. A localization of acyl-CoA oxidase in the endoplasmic reticulum seems to be in good accordance with the important role of peroxisomes in the metabolism of prostaglandins, as recently demonstrated by Diczfalusy, Kase, Alexson & Bjørkhem [(1991) J. Clin. Invest. 88, 978-984].
| S-EPMC1132979 | biostudies-other
Project description:Although the malonyl-CoA sensitivity of peroxisomal carnitine octanoyltransferase (COT) is reportedly lost on solubilization, we show that malonyl-CoA does inhibit the purified enzyme. Assay conditions such as buffer composition, pH, acyl-CoA substrate and the presence or absence of BSA can affect the observed inhibition. When assayed in the absence of BSA, COT shows simple competitive inhibition by malonyl-CoA. The Ki value for inhibition of purified COT is high (106 microM) compared with physiological concentrations (1-6 microM) and other short-chain acyl-CoA esters inhibit COT to the same degree. However, when COT is assayed in intact peroxisomes, the Ki for malonyl-CoA is almost 20-fold lower than found with the purified enzyme, whereas inhibition by other short-chain acyl-CoA esters does not change significantly. Several features of the inhibition of peroxisomal COT, including the specificity of malonyl-CoA over other short-chain acyl-CoA esters, resemble those of carnitine palmitoyltransferase (CPT)-I, suggesting that the regulation of COT and CPT-I in parallel may be necessary for the control of cellular fatty acid metabolism.
| S-EPMC1132947 | biostudies-other
Project description:Autophagy is a membrane trafficking pathway that sequesters proteins and organelles into autophagosomes. The selectivity of this pathway is determined by autophagy receptors, such as the Pichia pastoris autophagy-related protein 30 (Atg30), which controls the selective autophagy of peroxisomes (pexophagy) through the assembly of a receptor protein complex (RPC). However, how the pexophagic RPC is regulated for efficient formation of the phagophore, an isolation membrane that sequesters the peroxisome from the cytosol, is unknown. Here we describe a new, conserved acyl-CoA-binding protein, Atg37, that is an integral peroxisomal membrane protein required specifically for pexophagy at the stage of phagophore formation. Atg30 recruits Atg37 to the pexophagic RPC, where Atg37 regulates the recruitment of the scaffold protein, Atg11. Palmitoyl-CoA competes with Atg30 for Atg37 binding. The human orthologue of Atg37, acyl-CoA-binding domain containing protein 5 (ACBD5), is also peroxisomal and is required specifically for pexophagy. We suggest that Atg37/ACBD5 is a new component and positive regulator of the pexophagic RPC.
| S-EPMC3926955 | biostudies-literature