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Biomolecules Nov 2022Phosphatidic acid (PA) is a signaling lipid that is produced enzymatically from phosphatidylcholine (PC), lysophosphatidic acid, or diacylglycerol. Compared to PC, PA...
Phosphatidic acid (PA) is a signaling lipid that is produced enzymatically from phosphatidylcholine (PC), lysophosphatidic acid, or diacylglycerol. Compared to PC, PA lacks a choline moiety on the headgroup, making the headgroup smaller than that of PC and PA, and PA has a net negative charge. Unlike the cylindrical geometry of PC, PA, with its small headgroup relative to the two fatty acid tails, is proposed to support negatively curved membranes. Thus, PA is thought to play a role in a variety of biological processes that involve bending membranes, such as the formation of intraluminal vesicles in multivesicular bodies and membrane fusion. Using supported tubulated lipid bilayers (STuBs), the extent to which PA localizes to curved membranes was determined. STuBs were created via liposome deposition with varying concentrations of NaCl (500 mM to 1 M) on glass to form supported bilayers with connected tubules. The location of fluorescently labeled lipids relative to tubules was determined by imaging with total internal reflection or confocal fluorescence microscopy. The accumulation of various forms of PA (with acyl chains of 16:0-6:0, 16:0-12:0, 18:1-12:0) were compared to PC and the headgroup labeled phosphatidylethanolamine (PE), a lipid that has been shown to accumulate at regions of curvature. PA and PE accumulated more at tubules and led to the formation of more tubules than PC. Using large unilamellar liposomes in a dye-quenching assay, the location of the headgroup labeled PE was determined to be mostly on the outer, positively curved leaflet, whereas the tail labeled PA was located more on the inner, negatively curved leaflet. This study demonstrates that PA localizes to regions of negative curvature in liposomes and supports the formation of curved, tubulated membranes. This is one way that PA could be involved with curvature formation during a variety of cell processes.
Topics: Lipid Bilayers; Phosphatidic Acids; Lecithins; Unilamellar Liposomes; Membrane Fusion
PubMed: 36421720
DOI: 10.3390/biom12111707 -
Biochemical Pharmacology Dec 2022In mammalian cells, phospholipids and cholesterol are assembled into bilayer membranes forming the plasma membrane, nuclear envelope, mitochondria, endoplasmic... (Review)
Review
In mammalian cells, phospholipids and cholesterol are assembled into bilayer membranes forming the plasma membrane, nuclear envelope, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, and endosomes. Phospholipids are divided into classes based on the molecular structures, including phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidic acid, phosphatidylinositol, phosphatidylglycerol, cardiolipin, and sphingomyelin. In addition to their structural roles, phospholipids play important roles in many cellular processes, such as membrane protein regulation, membrane trafficking, cell growth, apoptosis, and intracellular signaling. Thus, abnormal phospholipid metabolism is associated with various diseases. In mammalian cells, phospholipid classes are generated through several enzymatic steps, predominantly in the endoplasmic reticulum, mitochondria, and Golgi apparatus. In recent years, various enzymes involved in the biosynthesis of phospholipid classes have been identified. However, little is known about the regulatory mechanisms underlying the biosynthesis of phospholipid classes. Using our recently developed enzymatic fluorometric assays for all major phospholipid classes, we have demonstrated changes in phospholipid composition in intracellular organelles during cell growth. In this review, we summarize the current understanding of the properties and functions of phospholipid biosynthesis enzymes, and discuss their regulatory mechanisms.
Topics: Animals; Phospholipids; Endoplasmic Reticulum; Mitochondria; Cell Membrane; Phosphatidylserines; Mammals
PubMed: 36241095
DOI: 10.1016/j.bcp.2022.115296 -
Communications Biology Sep 2022Construction of living artificial cells from genes and molecules can expand our understanding of life system and establish a new aspect of bioengineering. However,...
Construction of living artificial cells from genes and molecules can expand our understanding of life system and establish a new aspect of bioengineering. However, growth and division of cell membrane that are basis of cell proliferation are still difficult to reconstruct because a high-yielding phospholipid synthesis system has not been established. Here, we developed a cell-free phospholipid synthesis system that combines fatty acid synthesis and cell-free gene expression system synthesizing acyltransferases. The synthesized fatty acids were sequentially converted into phosphatidic acids by the cell-free synthesized acyltransferases. Because the system can avoid the accumulation of intermediates inhibiting lipid synthesis, sub-millimolar phospholipids could be synthesized within a single reaction mixture. We also performed phospholipid synthesis inside phospholipid membrane vesicles, which encapsulated all the components, and showed the phospholipids localized onto the mother membrane. Our approach would be a platform for the construction of self-reproducing artificial cells since the membrane can grow sustainably.
Topics: Acyltransferases; Cell Membrane; Escherichia coli; Fatty Acids; Phosphatidic Acids
PubMed: 36167778
DOI: 10.1038/s42003-022-03999-1 -
Biochimica Et Biophysica Acta.... Sep 2021Phosphatidylinositol is the parent lipid for the synthesis of seven phosphorylated inositol lipids and each of them play specific roles in numerous processes including... (Review)
Review
Phosphatidylinositol is the parent lipid for the synthesis of seven phosphorylated inositol lipids and each of them play specific roles in numerous processes including receptor-mediated signalling, actin cytoskeleton dynamics and membrane trafficking. PI synthesis is localised to the endoplasmic reticulum (ER) whilst its phosphorylated derivatives are found in other organelles where the lipid kinases also reside. Phosphorylation of PI to phosphatidylinositol (4,5) bisphosphate (PI(4,5)P) at the plasma membrane and to phosphatidylinositol 4-phosphate (PI4P) at the Golgi are key events in lipid signalling and Golgi function respectively. Here we review a family of proteins, phosphatidylinositol transfer proteins (PITPs), that can mobilise PI from the ER to provide the substrate to the resident kinases for phosphorylation. Recent studies identify specific and overlapping functions for the three soluble PITPs (PITPα, PITPβ and PITPNC1) in phospholipase C signalling, neuronal function, membrane trafficking, viral replication and in cancer metastases.
Topics: Biological Transport; Cell Membrane; Endoplasmic Reticulum; Phosphatidylinositols; Signal Transduction
PubMed: 34111527
DOI: 10.1016/j.bbalip.2021.158985 -
Biological Reviews of the Cambridge... Aug 2020The phospholipase D (PLD) family has a ubiquitous expression in cells. PLD isoforms (PLDs) and their hydrolysate phosphatidic acid (PA) have been demonstrated to engage... (Review)
Review
The phospholipase D (PLD) family has a ubiquitous expression in cells. PLD isoforms (PLDs) and their hydrolysate phosphatidic acid (PA) have been demonstrated to engage in multiple stages of cancer progression. Aberrant expression of PLDs, especially PLD1 and PLD2, has been detected in various cancers. Inhibition or elimination of PLDs activity has been shown to reduce tumour growth and metastasis. PLDs and PA also serve as downstream effectors of various cell-surface receptors, to trigger and regulate propagation of intracellular signals in the process of tumourigenesis and metastasis. Here, we discuss recent advances in understanding the functions of PLDs and PA in discrete stages of cancer progression, including cancer cell growth, invasion and migration, and angiogenesis, with special emphasis on the tumour-associated signalling pathways mediated by PLDs and PA and the functional importance of PLDs and PA in cancer therapy.
Topics: Angiogenesis Inducing Agents; Animals; Cell Movement; Disease Progression; Epithelial-Mesenchymal Transition; Humans; Mice; Neoplasm Invasiveness; Neoplasm Metastasis; Neoplasms; Phosphatidic Acids; Phospholipase D; Receptors, Growth Factor
PubMed: 32073216
DOI: 10.1111/brv.12592 -
Biochemistry. Biokhimiia Mar 2023Lipids comprise an extremely heterogeneous group of compounds that perform a wide variety of biological functions. Traditional view of lipids as important structural... (Review)
Review
Lipids comprise an extremely heterogeneous group of compounds that perform a wide variety of biological functions. Traditional view of lipids as important structural components of the cell and compounds playing a trophic role is currently being supplemented by information on the possible participation of lipids in signaling, not only intracellular, but also intercellular. The review article discusses current data on the role of lipids and their metabolites formed in glial cells (astrocytes, oligodendrocytes, microglia) in communication of these cells with neurons. In addition to metabolic transformations of lipids in each type of glial cells, special attention is paid to the lipid signal molecules (phosphatidic acid, arachidonic acid and its metabolites, cholesterol, etc.) and the possibility of their participation in realization of synaptic plasticity, as well as in other possible mechanisms associated with neuroplasticity. All these new data can significantly expand our knowledge about the regulatory functions of lipids in neuroglial relationships.
Topics: Arachidonic Acid; Astrocytes; Cell Communication; Cholesterol; Lipids; Microglia; Neuroglia; Neuronal Plasticity; Neurons; Oligodendroglia; Phosphatidic Acids; Signal Transduction; Humans; Animals
PubMed: 37076281
DOI: 10.1134/S0006297923030045 -
ACS Chemical Biology Aug 2023-Acyl-phosphatidylethanolamine hydrolyzing phospholipase D (NAPE-PLD) is a zinc metallohydrolase that hydrolyzes -acyl-phosphatidylethanolamines (NAPEs) to form...
-Acyl-phosphatidylethanolamine hydrolyzing phospholipase D (NAPE-PLD) is a zinc metallohydrolase that hydrolyzes -acyl-phosphatidylethanolamines (NAPEs) to form -acyl-ethanolamines (NAEs) and phosphatidic acid. Several lines of evidence suggest that reduced NAPE-PLD activity could contribute to cardiometabolic diseases. For instance, expression is reduced in human coronary arteries with unstable atherosclerotic lesions, defective efferocytosis is implicated in the enlargement of necrotic cores of these lesions, and NAPE-PLD products such as palmitoylethanolamide and oleoylethanolamide have been shown to enhance efferocytosis. Thus, enzyme activation mediated by a small molecule may serve as a therapeutic treatment for cardiometabolic diseases. As a proof-of-concept study, we sought to identify small molecule activators of NAPE-PLD. High-throughput screening followed by hit validation and primary lead optimization studies identified a series of benzothiazole phenylsulfonyl-piperidine carboxamides that variably increased activity of both mouse and human NAPE-PLD. From this set of small molecules, two NAPE-PLD activators ( and ) were shown to increase efferocytosis by bone-marrow derived macrophages isolated from wild-type mice, while efferocytosis was significantly reduced in BMDM or after Nape-pld inhibition. Together, these studies demonstrate an essential role for NAPE-PLD in the regulation of efferocytosis and the potential value of NAPE-PLD activators as a strategy to treat cardiometabolic diseases.
Topics: Mice; Humans; Animals; Phospholipase D; Phosphatidylethanolamines; Brain; Macrophages; Cardiovascular Diseases
PubMed: 37531659
DOI: 10.1021/acschembio.3c00401 -
Journal of the American Chemical Society Apr 2022TRAAK and TREK2 are two-pore domain K (K2P) channels and are modulated by diverse factors including temperature, membrane stretching, and lipids, such as phosphatidic...
TRAAK and TREK2 are two-pore domain K (K2P) channels and are modulated by diverse factors including temperature, membrane stretching, and lipids, such as phosphatidic acid. In addition, copper and zinc, both of which are essential for life, are known to regulate TREK2 and a number of other ion channels. However, the role of ions in the association of lipids with integral membrane proteins is poorly understood. Here, we discover cupric ions selectively modulate the binding of phosphatidylserine (PS) to TRAAK but not TREK2. Other divalent cations (Ca, Mg, and Zn) bind both channels but have no impact on binding PS and other lipids. Additionally, TRAAK binds more avidly to Cu and Zn than TREK2. In the presence of Cu, TRAAK binds similarly to PS with different acyl chains, indicating a crucial role of the serine headgroup in coordinating Cu. High-resolution native mass spectrometry (MS) enables the determination of equilibrium binding constants for distinct Cu-bound stoichiometries and uncovered the highest coupling factor corresponds to a 1:1 PS-to-Cu ratio. Interestingly, the next three highest coupling factors had a ∼1.5:1 PS-to-Cu ratio. Our findings bring forth the role of cupric ions as an essential cofactor in selective TRAAK-PS interactions.
Topics: Cations, Divalent; Phosphatidylserines; Potassium Channels, Tandem Pore Domain
PubMed: 35421309
DOI: 10.1021/jacs.2c00612 -
ACS Central Science Jul 2021Phosphatidic acids (PAs) are glycerophospholipids that regulate key cell signaling pathways governing cell growth and proliferation, including the mTOR and Hippo...
Phosphatidic acids (PAs) are glycerophospholipids that regulate key cell signaling pathways governing cell growth and proliferation, including the mTOR and Hippo pathways. Their acyl chains vary in tail length and degree of saturation, leading to marked differences in the signaling functions of different PA species. For example, in mTOR signaling, saturated forms of PA are inhibitory, whereas unsaturated forms are activating. To enable rapid control over PA signaling, we describe here the development of photoswitchable analogues of PA, termed and , that contain azobenzene groups in one or both lipid tails, respectively. These photolipids enable optical control of their tail structure and can be reversibly switched between a straight form and a relatively bent form. We found that - selectively activates mTOR signaling, mimicking the bioactivity of unsaturated forms of PA. Further, in the context of Hippo signaling, whose growth-suppressing activity is blocked by PA, we found that the forms of both and selectively inhibit this pathway. Collectively, these photoswitchable PA analogues enable optical control of mTOR and Hippo signaling, and we envision future applications of these probes to dissect the pleiotropic effects of physiological and pathological PA signaling.
PubMed: 34345670
DOI: 10.1021/acscentsci.1c00444 -
Journal of Neurochemistry Nov 2022Major depressive disorder (MDD) is a severe disease of unknown pathogenesis with a lifetime prevalence of ~10%. Therapy requires prolonged treatment that often fails. We...
Major depressive disorder (MDD) is a severe disease of unknown pathogenesis with a lifetime prevalence of ~10%. Therapy requires prolonged treatment that often fails. We have previously demonstrated that ceramide levels in the blood plasma of patients and in mice with experimental MDD are increased. Neutralization of blood plasma ceramide prevented experimental MDD in mice. Mechanistically, we demonstrated that blood plasma ceramide accumulated in endothelial cells of the hippocampus, inhibited phospholipase D (PLD) and thereby decreased phosphatidic acid in the hippocampus. Here, we demonstrate that phosphatidic acid binds to and controls the activity of phosphotyrosine phosphatase (PTP1B) in the hippocampus and thus determines tyrosine phosphorylation of a variety of cellular proteins including TrkB. Injection of PLD, phosphatidic acid, or inhibition of PTP1B abrogated MDD and normalized cellular tyrosine phosphorylation, including phosphorylation of TrkB and neurogenesis in the hippocampus. Most importantly, these treatments also rapidly normalized behavior of mice with experimental MDD. Since phosphatidic acid binds to and inhibits PTP1B, the lack of phosphatidic acid results in increased activity of PTP1B and thereby in reduced tyrosine phosphorylation of TrkB and other cellular proteins. Thus, our data indicate a novel pathogenetic mechanism of and a rapidly acting targeted treatment for MDD.
Topics: Mice; Animals; Phosphatidic Acids; Depressive Disorder, Major; Endothelial Cells; Phosphorylation; Ceramides; Tyrosine
PubMed: 36227646
DOI: 10.1111/jnc.15708