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Function (Oxford, England) 2023The maintenance of phospholipid homeostasis is increasingly being implicated in metabolic health. Phosphatidylethanolamine (PE) is the most abundant phospholipid on the...
The maintenance of phospholipid homeostasis is increasingly being implicated in metabolic health. Phosphatidylethanolamine (PE) is the most abundant phospholipid on the inner leaflet of cellular membranes, and we have previously shown that mice with a heterozygous ablation of the PE synthesizing enzyme, Pcyt2 (), develop obesity, insulin resistance, and NASH. Skeletal muscle is a major determinant of systemic energy metabolism, making it a key player in metabolic disease development. Both the total PE levels and the ratio of PE to other membrane lipids in skeletal muscle are implicated in insulin resistance; however, the underlying mechanisms and the role of Pcyt2 regulation in this association remain unclear. Here, we show how reduced phospholipid synthesis due to Pcyt2 deficiency causes skeletal muscle dysfunction and metabolic abnormalities. skeletal muscle exhibits damage and degeneration, with skeletal muscle cell vacuolization, disordered sarcomeres, mitochondria ultrastructure irregularities and paucity, inflammation, and fibrosis. There is intramuscular adipose tissue accumulation, and major disturbances in lipid metabolism with impaired FA mobilization and oxidation, elevated lipogenesis, and long-chain fatty acyl-CoA, diacylglycerol, and triacylglycerol accumulation. skeletal muscle exhibits perturbed glucose metabolism with elevated glycogen content, impaired insulin signaling, and reduced glucose uptake. Together, this study lends insight into the critical role of PE homeostasis in skeletal muscle metabolism and health with broad implications on metabolic disease development.
Topics: Mice; Animals; Lipogenesis; Insulin Resistance; Phosphatidylethanolamines; Triglycerides; Muscle, Skeletal
PubMed: 37342414
DOI: 10.1093/function/zqad020 -
Free Radical Biology & Medicine Nov 2023Ferroptosis is a regulated form of cell death, the mechanism of which is still to be understood. 15-lipoxygenase (15LOX) complex with phosphatidylethanolamine...
Ferroptosis is a regulated form of cell death, the mechanism of which is still to be understood. 15-lipoxygenase (15LOX) complex with phosphatidylethanolamine (PE)-binding protein 1 (PEBP1) catalyzes the generation of pro-ferroptotic cell death signals, hydroperoxy-polyunsaturated PE. We focused on gaining new insights into the molecular basis of these pro-ferroptotic interactions using computational modeling and liquid chromatography-mass spectrometry experiments. Simulations of 15LOX-1/PEBP1 complex dynamics and interactions with lipids revealed that association with the membrane triggers a conformational change in the complex. This conformational change facilitates the access of stearoyl/arachidonoyl-PE (SAPE) substrates to the catalytic site. Furthermore, the binding of SAPE promotes tight interactions within the complex and induces further conformational changes that facilitate the oxidation reaction. The reaction yields two hydroperoxides as products, 15-HpETE-PE and 12-HpETE-PE, at a ratio of 5:1. A significant effect of PEBP1 is observed only on the predominant product. Moreover, combined experiments and simulations consistently demonstrate the significance of PEBP1 P112E mutation in generating ferroptotic cell death signals.
Topics: Cell Death; Ferroptosis; Oxidation-Reduction; Arachidonate 15-Lipoxygenase; Phosphatidylethanolamine Binding Protein; Phosphatidylethanolamines; Humans; Animals; Swine
PubMed: 37678654
DOI: 10.1016/j.freeradbiomed.2023.09.001 -
Methods in Molecular Biology (Clifton,... 2023N-Acyl-phosphatidylethanolamine (NAPE)-hydrolyzing phospholipase D (NAPE-PLD) is a prominent enzyme involved in the biosynthesis of fatty acid amides, a family of...
N-Acyl-phosphatidylethanolamine (NAPE)-hydrolyzing phospholipase D (NAPE-PLD) is a prominent enzyme involved in the biosynthesis of fatty acid amides, a family of bioactive lipids including anandamide as the prototypical member. Here, we describe a NAPE-PLD assay based on radioactive substrates and product separation by thin layer chromatography (TLC).
Topics: Biological Assay; Chromatography, Thin Layer; Phosphatidylethanolamines; Phospholipase D
PubMed: 36152190
DOI: 10.1007/978-1-0716-2728-0_18 -
Biochimica Et Biophysica Acta.... Jan 2017Mitochondria are unique organelles that contain their own - although strongly reduced - genome, and are surrounded by two membranes. While most cellular phospholipid... (Review)
Review
Mitochondria are unique organelles that contain their own - although strongly reduced - genome, and are surrounded by two membranes. While most cellular phospholipid biosynthesis takes place in the ER, mitochondria harbor the whole spectrum of glycerophospholipids common to biological membranes. Mitochondria also contribute to overall phospholipid biosynthesis in cells by producing phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin. Considering these features, it is not surprising that mitochondria maintain highly active exchange of phospholipids with other cellular compartments. In this contribution we describe the transport of phospholipids between mitochondria and other organelles, and discuss recent developments in our understanding of the molecular functions of the protein complexes that mediate these processes. This article is part of a Special Issue entitled: Lipids of Mitochondria edited by Guenther Daum.
Topics: Animals; Biological Transport; Cardiolipins; Endoplasmic Reticulum; Humans; Membrane Proteins; Mitochondria; Mitochondrial Membranes; Phosphatidylethanolamines; Phospholipids
PubMed: 27477677
DOI: 10.1016/j.bbalip.2016.07.010 -
Biochimica Et Biophysica Acta Aug 2014Membrane protein folding and topogenesis are tuned to a given lipid profile since lipids and proteins have co-evolved to follow a set of interdependent rules governing... (Review)
Review
Membrane protein folding and topogenesis are tuned to a given lipid profile since lipids and proteins have co-evolved to follow a set of interdependent rules governing final protein topological organization. Transmembrane domain (TMD) topology is determined via a dynamic process in which topogenic signals in the nascent protein are recognized and interpreted initially by the translocon followed by a given lipid profile in accordance with the Positive Inside Rule. The net zero charged phospholipid phosphatidylethanolamine and other neutral lipids dampen the translocation potential of negatively charged residues in favor of the cytoplasmic retention potential of positively charged residues (Charge Balance Rule). This explains why positively charged residues are more potent topological signals than negatively charged residues. Dynamic changes in orientation of TMDs during or after membrane insertion are attributed to non-sequential cooperative and collective lipid-protein charge interactions as well as long-term interactions within a protein. The proportion of dual topological conformers of a membrane protein varies in a dose responsive manner with changes in the membrane lipid composition not only in vivo but also in vitro and therefore is determined by the membrane lipid composition. Switching between two opposite TMD topologies can occur in either direction in vivo and also in liposomes (designated as fliposomes) independent of any other cellular factors. Such lipid-dependent post-insertional reversibility of TMD orientation indicates a thermodynamically driven process that can occur at any time and in any cell membrane driven by changes in the lipid composition. This dynamic view of protein topological organization influenced by the lipid environment reveals previously unrecognized possibilities for cellular regulation and understanding of disease states resulting from mis-folded proteins. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
Topics: Bacteria; Cell Membrane; Cytoplasm; Lipids; Membrane Proteins; Phosphatidylethanolamines; Protein Folding; Protein Structure, Tertiary; Protein Transport
PubMed: 24341994
DOI: 10.1016/j.bbamcr.2013.12.007 -
Biochimica Et Biophysica Acta.... Jan 2017Phosphatidylethanolamine is one of the most abundant phospholipids whose major amounts are formed by phosphatidylserine decarboxylases (PSD). Here we provide a... (Review)
Review
Phosphatidylethanolamine is one of the most abundant phospholipids whose major amounts are formed by phosphatidylserine decarboxylases (PSD). Here we provide a comprehensive description of different types of PSDs in the different kingdoms of life. In eukaryotes, type I PSDs are mitochondrial enzymes, whereas other PSDs are localized to other cellular compartments. We describe the role of mitochondrial Psd1 proteins, their function, enzymology, biogenesis, assembly into mitochondria and their contribution to phospholipid homeostasis in much detail. We also discuss briefly the cellular physiology and the enzymology of Psd2. This article is part of a Special Issue entitled: Lipids of Mitochondria edited by Guenther Daum.
Topics: Amino Acid Sequence; Animals; Carboxy-Lyases; Homeostasis; Humans; Mitochondria; Mitochondrial Proteins; Phosphatidylethanolamines; Phospholipids
PubMed: 27650064
DOI: 10.1016/j.bbalip.2016.09.007 -
The Journal of Biological Chemistry 2021Lipid flipping in the membrane bilayers is a widespread eukaryotic phenomenon that is catalyzed by assorted P4-ATPases. Its occurrence, mechanism, and importance in...
Lipid flipping in the membrane bilayers is a widespread eukaryotic phenomenon that is catalyzed by assorted P4-ATPases. Its occurrence, mechanism, and importance in apicomplexan parasites have remained elusive, however. Here we show that Toxoplasma gondii, an obligate intracellular parasite with high clinical relevance, can salvage phosphatidylserine (PtdSer) and phosphatidylethanolamine (PtdEtn) but not phosphatidylcholine (PtdCho) probes from its milieu. Consistently, the drug analogs of PtdCho are broadly ineffective in the parasite culture. NBD-PtdSer imported to the parasite interior is decarboxylated to NBD-PtdEtn, while the latter is not methylated to yield PtdCho, which confirms the expression of PtdSer decarboxylase but a lack of PtdEtn methyltransferase activity and suggests a role of exogenous lipids in membrane biogenesis of T. gondii. Flow cytometric quantitation of NBD-probes endorsed the selectivity of phospholipid transport and revealed a dependence of the process on energy and protein. Accordingly, our further work identified five P4-ATPases (TgP4-ATPase1-5), all of which harbor the signature residues and motifs required for phospholipid flipping. Of the four proteins expressed during the lytic cycle, TgP4-ATPase1 is present in the apical plasmalemma; TgP4-ATPase3 resides in the Golgi network along with its noncatalytic partner Ligand Effector Module 3 (TgLem3), whereas TgP4-ATPase2 and TgP4-ATPase5 localize in the plasmalemma as well as endo/cytomembranes. Last but not least, auxin-induced degradation of TgP4-ATPase1-3 impaired the parasite growth in human host cells, disclosing their crucial roles during acute infection. In conclusion, we show selective translocation of PtdEtn and PtdSer at the parasite surface and provide the underlying mechanistic and physiological insights in a model eukaryotic pathogen.
Topics: Adenosine Triphosphatases; Cell Membrane; Flow Cytometry; Glycerophospholipids; Golgi Apparatus; Humans; Lipid Bilayers; Lipids; Phosphatidylcholines; Phosphatidylethanolamines; Phosphatidylserines; Toxoplasma; Toxoplasmosis
PubMed: 33485966
DOI: 10.1016/j.jbc.2021.100315 -
Nature Communications Aug 2020Lipid membranes, nucleic acids, proteins, and metabolism are essential for modern cellular life. Synthetic systems emulating the fundamental properties of living cells...
Lipid membranes, nucleic acids, proteins, and metabolism are essential for modern cellular life. Synthetic systems emulating the fundamental properties of living cells must therefore be built upon these functional elements. In this work, phospholipid-producing enzymes encoded in a synthetic minigenome are cell-free expressed within liposome compartments. The de novo synthesized metabolic pathway converts precursors into a variety of lipids, including the constituents of the parental liposome. Balanced production of phosphatidylethanolamine and phosphatidylglycerol is realized, owing to transcriptional regulation of the activity of specific genes combined with a metabolic feedback mechanism. Fluorescence-based methods are developed to image the synthesis and membrane incorporation of phosphatidylserine at the single liposome level. Our results provide experimental evidence for DNA-programmed membrane synthesis in a minimal cell model. Strategies are discussed to alleviate current limitations toward effective liposome growth and self-reproduction.
Topics: Escherichia coli; Gene Expression; Liposomes; Membrane Lipids; Phosphatidylethanolamines; Phosphatidylglycerols; Phospholipids; Proteomics
PubMed: 32859896
DOI: 10.1038/s41467-020-17863-5 -
Pharmacological Research Aug 2014Fatty acyl ethanolamides represent a class of endogenous bioactive lipid molecules and are generally referred to as N-acylethanolamines (NAEs). NAEs include... (Review)
Review
Fatty acyl ethanolamides represent a class of endogenous bioactive lipid molecules and are generally referred to as N-acylethanolamines (NAEs). NAEs include palmitoylethanolamide (anti-inflammatory and analgesic substance), oleoylethanolamide (anorexic substance), and anandamide (endocannabinoid). The endogenous levels of NAEs are mainly regulated by enzymes responsible for their biosynthesis and degradation. In mammalian tissues, the major biosynthetic pathway starts from glycerophospholipids and is composed of two enzyme reactions. The first step is N-acylation of ethanolamine phospholipids catalyzed by Ca(2+)-dependent N-acyltransferase and the second step is the release of NAEs from N-acylated ethanolamine phospholipids by N-acylphosphatidylethanolamine (NAPE)-hydrolyzing phospholipase D (NAPE-PLD). As for the degradation of NAEs, fatty acid amide hydrolase plays the central role. However, recent studies strongly suggest the involvement of other enzymes in the NAE metabolism. These enzymes include members of the HRAS-like suppressor family (also called phospholipase A/acyltransferase family), which were originally discovered as tumor suppressors but can function as Ca(2+)-independent NAPE-forming N-acyltransferases; multiple enzymes involved in the NAPE-PLD-independent multi-step pathways to generate NAE from NAPE, which came to light by the analysis of NAPE-PLD-deficient mice; and a lysosomal NAE-hydrolyzing acid amidase as a second NAE hydrolase. These newly recognized enzymes may become the targets for the development of new therapeutic drugs. Here, we focus on recent enzymological findings in this area.
Topics: Acyltransferases; Amides; Animals; Endocannabinoids; Ethanolamines; Humans; Oleic Acids; Palmitic Acids; Phosphatidylethanolamines; Phospholipase D
PubMed: 24747663
DOI: 10.1016/j.phrs.2014.04.001 -
Nature Chemical Biology Dec 2020Maintenance of lipid asymmetry across the two leaflets of the plasma membrane (PM) bilayer is a ubiquitous feature of eukaryotic cells. Loss of this asymmetry has been... (Review)
Review
Maintenance of lipid asymmetry across the two leaflets of the plasma membrane (PM) bilayer is a ubiquitous feature of eukaryotic cells. Loss of this asymmetry has been widely associated with cell death. However, increasing evidence points to the physiological importance of non-apoptotic, transient changes in PM asymmetry. Such transient scrambling events are associated with a range of biological functions, including intercellular communication and intracellular signaling. Thus, regulation of interleaflet lipid distribution in the PM is a broadly important but underappreciated cellular process with key physiological and structural consequences. Here, we compile the mounting evidence revealing multifaceted, functional roles of PM asymmetry and transient loss thereof. We discuss the consequences of reversible asymmetry on PM structure, biophysical properties and interleaflet coupling. We argue that despite widespread recognition of broad aspects of membrane asymmetry, its importance in cell biology demands more in-depth investigation of its features, regulation, and physiological and pathological implications.
Topics: Animals; Cell Communication; Cell Membrane; Cholesterol; Erythrocytes; Humans; Lipid Bilayers; Mammals; Neurons; Phosphatidylcholines; Phosphatidylethanolamines; Phosphatidylinositols; Phosphatidylserines; Signal Transduction; Sphingomyelins
PubMed: 33199908
DOI: 10.1038/s41589-020-00688-0