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The Journal of Cell Biology Mar 2022Glycosylphosphatidylinositol (GPI) is a glycolipid membrane anchor found on surface proteins in all eukaryotes. It is synthesized in the ER membrane. Each GPI anchor...
Glycosylphosphatidylinositol (GPI) is a glycolipid membrane anchor found on surface proteins in all eukaryotes. It is synthesized in the ER membrane. Each GPI anchor requires three molecules of ethanolamine phosphate (P-Etn), which are derived from phosphatidylethanolamine (PE). We found that efficient GPI anchor synthesis in Saccharomyces cerevisiae requires Csf1; cells lacking Csf1 accumulate GPI precursors lacking P-Etn. Structure predictions suggest Csf1 is a tube-forming lipid transport protein like Vps13. Csf1 is found at contact sites between the ER and other organelles. It interacts with the ER protein Mcd4, an enzyme that adds P-Etn to nascent GPI anchors, suggesting Csf1 channels PE to Mcd4 in the ER at contact sites to support GPI anchor biosynthesis. CSF1 has orthologues in Caenorhabditis elegans (lpd-3) and humans (KIAA1109/TWEEK); mutations in KIAA1109 cause the autosomal recessive neurodevelopmental disorder Alkuraya-Kučinskas syndrome. Knockout of lpd-3 and knockdown of KIAA1109 reduced GPI-anchored proteins on the surface of cells, suggesting Csf1 orthologues in human cells support GPI anchor biosynthesis.
Topics: Autophagy; Endoplasmic Reticulum; Glycosylphosphatidylinositols; Mitochondria; Phosphatidylethanolamines; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins
PubMed: 35015055
DOI: 10.1083/jcb.202111095 -
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 -
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 Oct 2016This review summarises high resolution studies on the interface of lamellar lipid bilayers composed of the most typical lipid molecules which constitute the lipid matrix... (Review)
Review
This review summarises high resolution studies on the interface of lamellar lipid bilayers composed of the most typical lipid molecules which constitute the lipid matrix of biomembranes. The presented results were obtained predominantly by computer modelling methods. Whenever possible, the results were compared with experimental results obtained for similar systems. The first and main section of the review is concerned with the bilayer-water interface and is divided into four subsections. The first describes the simplest case, where the interface consists only of lipid head groups and water molecules and focuses on interactions between the lipid heads and water molecules; the second describes the interface containing also mono- and divalent ions and concentrates on lipid-ion interactions; the third describes direct inter-lipid interactions. These three subsections are followed by a discussion on the network of direct and indirect inter-lipid interactions at the bilayer interface. The second section summarises recent computer simulation studies on the interactions of antibacterial membrane active compounds with various models of the bacterial outer membrane. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg.
Topics: Computer Simulation; Hydrogen Bonding; Lipid Bilayers; Phosphatidylcholines; Phosphatidylethanolamines; Phosphatidylserines; Sphingomyelins; Water
PubMed: 26825705
DOI: 10.1016/j.bbamem.2016.01.024 -
Oxidative Medicine and Cellular... 2017Phosphatidylethanolamine (PE) is the second most abundant phospholipid in mammalian cells. PE comprises about 15-25% of the total lipid in mammalian cells; it is... (Review)
Review
Phosphatidylethanolamine (PE) is the second most abundant phospholipid in mammalian cells. PE comprises about 15-25% of the total lipid in mammalian cells; it is enriched in the inner leaflet of membranes, and it is especially abundant in the inner mitochondrial membrane. PE has quite remarkable activities: it is a lipid chaperone that assists in the folding of certain membrane proteins, it is required for the activity of several of the respiratory complexes, and it plays a key role in the initiation of autophagy. In this review, we focus on PE's roles in lipid-induced stress in the endoplasmic reticulum (ER), Parkinson's disease (PD), ferroptosis, and cancer.
Topics: Animals; Disease; Endoplasmic Reticulum Stress; Ethanolamine; Health; Humans; Models, Biological; Phosphatidylethanolamines
PubMed: 28785375
DOI: 10.1155/2017/4829180 -
Molecular Microbiology Sep 2006The recent development of specific probes for lipid molecules has led to the discovery of lipid domains in bacterial membranes, that is, of membrane areas differing in... (Review)
Review
The recent development of specific probes for lipid molecules has led to the discovery of lipid domains in bacterial membranes, that is, of membrane areas differing in lipid composition. A view of the membrane as a patchwork is replacing the assumption of lipid homogeneity inherent in the fluid mosaic model of Singer and Nicolson (Science 1972, 175: 720-731). If thus membranes have complex lipid structure, questions arise about how it is generated and maintained, and what its function might be. How do lipid domains relate to the functionally distinct regions in bacterial cells as they are identified by protein localization techniques? This review assesses the current knowledge on the existence of cardiolipin (CL) and phosphatidylethanolamine (PE) domains in bacterial cell membranes and on the specific cellular localization of certain membrane proteins, which include phospholipid synthases, and discusses possible mechanisms, both chemical and physiological, for the formation of the lipid domains. We propose that bacterial membranes contain a mosaic of microdomains of CL and PE, which are to a significant extent self-assembled according to their respective intrinsic chemical characteristics. We extend the discussion to the possible relevance of the domains to specific cellular processes, including cell division and sporulation.
Topics: Bacillus subtilis; Cardiolipins; Cell Membrane; Membrane Fluidity; Membrane Lipids; Membrane Proteins; Models, Biological; Phosphatidylethanolamines; Phospholipids; Protein Transport
PubMed: 16925550
DOI: 10.1111/j.1365-2958.2006.05317.x -
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 -
IUBMB Life Feb 2009Phosphatidylserine decarboxylases (PSDs) (E.C. 4.1.1.65) are enzymes which catalyze the formation of phosphatidylethanolamine (PtdEtn) by decarboxylation of... (Review)
Review
Phosphatidylserine decarboxylases (PSDs) (E.C. 4.1.1.65) are enzymes which catalyze the formation of phosphatidylethanolamine (PtdEtn) by decarboxylation of phosphatidylserine (PtdSer). This enzymatic activity has been identified in both prokaryotic and eukaryotic organisms. PSDs occur as two types of proteins depending on their localization and the sequence of a conserved motif. Type I PSDs include enzymes of eukaryotic mitochondria and bacterial origin which contain the amino acid sequence LGST as a characteristic motif. Type II PSDs are found in the endomembrane system of eukaryotes and contain a typical GGST motif. These characteristic motifs are considered as autocatalytic cleavage sites where proenzymes are split into alpha- and beta-subunits. The S-residue set free by this cleavage serves as an attachment site of a pyruvoyl group which is required for the activity of the enzymes. Moreover, PSDs harbor characteristic binding sites for the substrate PtdSer. Substrate supply to eukaryotic PSDs requires lipid transport because PtdSer synthesis and decarboxylation are spatially separated. Targeting of PSDs to their proper locations requires additional intramolecular domains. Mitochondrially localized type I PSDs are directed to the inner mitochondrial membrane by N-terminal targeting sequences. Type II PSDs also contain sequences in their N-terminal extensions which might be required for subcellular targeting. Lack of PSDs causes various defects in different cell types. The physiological relevance of these findings and the central role of PSDs in lipid metabolism will be discussed in this review.
Topics: Amino Acid Motifs; Amino Acid Sequence; Animals; Biological Transport; Carboxy-Lyases; Conserved Sequence; Decarboxylation; Eukaryotic Cells; Forecasting; Lipid Metabolism; Molecular Sequence Data; Phosphatidylethanolamines; Phylogeny; Prokaryotic Cells; Protein Structure, Tertiary; Sequence Homology, Amino Acid; Substrate Specificity
PubMed: 19165886
DOI: 10.1002/iub.159 -
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 -
Parasitology Aug 2010The biological membranes of Trypanosoma brucei contain a complex array of phospholipids that are synthesized de novo from precursors obtained either directly from the... (Review)
Review
The biological membranes of Trypanosoma brucei contain a complex array of phospholipids that are synthesized de novo from precursors obtained either directly from the host, or as catabolised endocytosed lipids. This paper describes the use of nanoflow electrospray tandem mass spectrometry and high resolution mass spectrometry in both positive and negative ion modes, allowing the identification of approximately 500 individual molecular phospholipids species from total lipid extracts of cultured bloodstream and procyclic form T. brucei. Various molecular species of all of the major subclasses of glycerophospholipids were identified including phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol as well as phosphatidic acid, phosphatidylglycerol and cardolipin, and the sphingolipids sphingomyelin, inositol phosphoceramide and ethanolamine phosphoceramide. The lipidomic data obtained in this study will aid future biochemical phenotyping of either genetically or chemically manipulated commonly used bloodstream and procyclic strains of Trypanosoma brucei. Hopefully this will allow a greater understanding of the bizarre world of lipids in this important human pathogen.
Topics: Humans; Lipids; Mass Spectrometry; Phosphatidic Acids; Phosphatidylcholines; Phosphatidylethanolamines; Phosphatidylglycerols; Phosphatidylinositols; Phosphatidylserines; Phospholipids; Trypanosoma brucei brucei; Trypanosomiasis
PubMed: 20602846
DOI: 10.1017/S0031182010000715