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Biochimica Et Biophysica Acta.... Sep 2017Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) are the most abundant phospholipids in all mammalian cell membranes. In the 1950s, Eugene Kennedy and... (Review)
Review
Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) are the most abundant phospholipids in all mammalian cell membranes. In the 1950s, Eugene Kennedy and co-workers performed groundbreaking research that established the general outline of many of the pathways of phospholipid biosynthesis. In recent years, the importance of phospholipid metabolism in regulating lipid, lipoprotein and whole-body energy metabolism has been demonstrated in numerous dietary studies and knockout animal models. The purpose of this review is to highlight the unappreciated impact of phospholipid metabolism on health and disease. Abnormally high, and abnormally low, cellular PC/PE molar ratios in various tissues can influence energy metabolism and have been linked to disease progression. For example, inhibition of hepatic PC synthesis impairs very low density lipoprotein secretion and changes in hepatic phospholipid composition have been linked to fatty liver disease and impaired liver regeneration after surgery. The relative abundance of PC and PE regulates the size and dynamics of lipid droplets. In mitochondria, changes in the PC/PE molar ratio affect energy production. We highlight data showing that changes in the PC and/or PE content of various tissues are implicated in metabolic disorders such as atherosclerosis, insulin resistance and obesity. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá.
Topics: Animals; Fatty Liver, Alcoholic; Humans; Intestinal Mucosa; Lipoproteins, VLDL; Liver; Liver Regeneration; Metabolic Diseases; Mitochondria; Muscle, Skeletal; Non-alcoholic Fatty Liver Disease; Phosphatidylcholines; Phosphatidylethanolamines
PubMed: 28411170
DOI: 10.1016/j.bbamem.2017.04.006 -
IUBMB Life Jun 2010The glycerophospholipids phosphatidylcholine (PC) and phosphatidylethanolamine (PE) account for greater than 50% of the total phospholipid species in eukaryotic... (Review)
Review
The glycerophospholipids phosphatidylcholine (PC) and phosphatidylethanolamine (PE) account for greater than 50% of the total phospholipid species in eukaryotic membranes and thus play major roles in the structure and function of those membranes. In most eukaryotic cells, PC and PE are synthesized by an aminoalcoholphosphotransferase reaction, which uses sn-1,2-diradylglycerol and either CDP-choline or CDP-ethanolamine, respectively. This is the last step in a biosynthetic pathway known as the Kennedy pathway, so named after Eugene Kennedy who elucidated it over 50 years ago. This review will cover various aspects of the Kennedy pathway including: each of the biosynthetic steps, the functions and roles of the phospholipid products PC and PE, and how the Kennedy pathway has the potential of being a chemotherapeutic target against cancer and various infectious diseases.
Topics: Amino Acid Sequence; Animals; Humans; Molecular Sequence Data; Phosphatidylcholines; Phosphatidylethanolamines; Sequence Alignment; Signal Transduction
PubMed: 20503434
DOI: 10.1002/iub.337 -
Traffic (Copenhagen, Denmark) Jan 2015Membranes of mammalian subcellular organelles contain defined amounts of specific phospholipids that are required for normal functioning of proteins in the membrane.... (Review)
Review
Membranes of mammalian subcellular organelles contain defined amounts of specific phospholipids that are required for normal functioning of proteins in the membrane. Despite the wide distribution of most phospholipid classes throughout organelle membranes, the site of synthesis of each phospholipid class is usually restricted to one organelle, commonly the endoplasmic reticulum (ER). Thus, phospholipids must be transported from their sites of synthesis to the membranes of other organelles. In this article, pathways and subcellular sites of phospholipid synthesis in mammalian cells are summarized. A single, unifying mechanism does not explain the inter-organelle transport of all phospholipids. Thus, mechanisms of phospholipid transport between organelles of mammalian cells via spontaneous membrane diffusion, via cytosolic phospholipid transfer proteins, via vesicles and via membrane contact sites are discussed. As an example of the latter mechanism, phosphatidylserine (PS) is synthesized on a region of the ER (mitochondria-associated membranes, MAM) and decarboxylated to phosphatidylethanolamine in mitochondria. Some evidence is presented suggesting that PS import into mitochondria occurs via membrane contact sites between MAM and mitochondria. Recent studies suggest that protein complexes can form tethers that link two types of organelles thereby promoting lipid transfer. However, many questions remain about mechanisms of inter-organelle phospholipid transport in mammalian cells.
Topics: Animals; Biological Transport; Endoplasmic Reticulum; Humans; Mitochondria; Mitochondrial Membranes; Phosphatidylethanolamines; Phospholipids
PubMed: 25243850
DOI: 10.1111/tra.12230 -
International Journal of Molecular... May 2022Phospholipids represent a crucial component for the structure of cell membranes. Phosphatidylcholine and phosphatidylethanolamine are two phospholipids that comprise the... (Review)
Review
Phospholipids represent a crucial component for the structure of cell membranes. Phosphatidylcholine and phosphatidylethanolamine are two phospholipids that comprise the majority of cell membranes. De novo biosynthesis of phosphatidylcholine and phosphatidylethanolamine occurs via the Kennedy pathway, and perturbations in the regulation of this pathway are linked to a variety of human diseases, including cancer. Altered phosphatidylcholine and phosphatidylethanolamine membrane content, phospholipid metabolite levels, and fatty acid profiles are frequently identified as hallmarks of cancer development and progression. This review summarizes the research on how phospholipid metabolism changes over oncogenic transformation, and how phospholipid profiling can differentiate between human cancer and healthy tissues, with a focus on colorectal cancer, breast cancer, and non-small cell lung cancer. The potential for phospholipids to serve as biomarkers for diagnostics, or as anticancer therapy targets, is also discussed.
Topics: Carcinoma, Non-Small-Cell Lung; Fatty Acids; Humans; Lung Neoplasms; Phosphatidylcholines; Phosphatidylethanolamines; Phospholipids
PubMed: 35563655
DOI: 10.3390/ijms23095266 -
The Journal of Cell Biology Aug 2020Mitochondria, so much more than just being energy factories, also have the capacity to synthesize macromolecules including phospholipids, particularly cardiolipin (CL)... (Review)
Review
Mitochondria, so much more than just being energy factories, also have the capacity to synthesize macromolecules including phospholipids, particularly cardiolipin (CL) and phosphatidylethanolamine (PE). Phospholipids are vital constituents of mitochondrial membranes, impacting the plethora of functions performed by this organelle. Hence, the orchestrated movement of phospholipids to and from the mitochondrion is essential for cellular integrity. In this review, we capture recent advances in the field of mitochondrial phospholipid biosynthesis and trafficking, highlighting the significance of interorganellar communication, intramitochondrial contact sites, and lipid transfer proteins in maintaining membrane homeostasis. We then discuss the physiological functions of CL and PE, specifically how they associate with protein complexes in mitochondrial membranes to support bioenergetics and maintain mitochondrial architecture.
Topics: Animals; Biological Transport; Cardiolipins; Energy Metabolism; Humans; Mitochondria; Mitochondrial Membranes; Mitochondrial Proteins; Phosphatidylethanolamines; Phospholipids; Signal Transduction
PubMed: 32614384
DOI: 10.1083/jcb.202003131 -
FEBS Letters Apr 2018Mitochondrial structure and function are influenced by the unique phospholipid composition of its membranes. While mitochondria contain all the major classes of... (Review)
Review
Mitochondrial structure and function are influenced by the unique phospholipid composition of its membranes. While mitochondria contain all the major classes of phospholipids, recent studies have highlighted specific roles of the nonbilayer-forming phospholipids phosphatidylethanolamine (PE) and cardiolipin (CL) in the assembly and activity of mitochondrial respiratory chain (MRC) complexes. The nonbilayer phospholipids are cone-shaped molecules that introduce curvature stress in the bilayer membrane and have been shown to impact mitochondrial fusion and fission. In addition to their overlapping roles in these mitochondrial processes, each nonbilayer phospholipid also plays a unique role in mitochondrial function; for example, CL is specifically required for MRC supercomplex formation. Recent discoveries of mitochondrial PE- and CL-trafficking proteins and prior knowledge of their biosynthetic pathways have provided targets for precisely manipulating nonbilayer phospholipid levels in the mitochondrial membranes in vivo. Thus, the genetic mutants of these pathways could be valuable tools in illuminating molecular functions and biophysical properties of nonbilayer phospholipids in driving mitochondrial bioenergetics and dynamics.
Topics: Animals; Cardiolipins; Electron Transport; Electron Transport Chain Complex Proteins; Humans; Mitochondria; Mitochondrial Proteins; Phosphatidylethanolamines; Protein Transport
PubMed: 29067684
DOI: 10.1002/1873-3468.12887 -
Biochimica Et Biophysica Acta.... Jan 2020The turnover of phospholipids plays an essential role in membrane lipid homeostasis by impacting both lipid head group and acyl chain composition. This review focusses... (Review)
Review
The turnover of phospholipids plays an essential role in membrane lipid homeostasis by impacting both lipid head group and acyl chain composition. This review focusses on the degradation and acyl chain remodeling of the major phospholipid classes present in the ER membrane of the reference eukaryote Saccharomyces cerevisiae, i.e. phosphatidylcholine (PC), phosphatidylinositol (PI) and phosphatidylethanolamine (PE). Phospholipid turnover reactions are introduced, and the occurrence and important functions of phospholipid remodeling in higher eukaryotes are briefly summarized. After presenting an inventory of established mechanisms of phospholipid acyl chain exchange, current knowledge of phospholipid degradation and remodeling by phospholipases and acyltransferases localized to the yeast ER is summarized. PC is subject to the PC deacylation-reacylation remodeling pathway (PC-DRP) involving a phospholipase B, the recently identified glycerophosphocholine acyltransferase Gpc1p, and the broad specificity acyltransferase Ale1p. PI is post-synthetically enriched in C18:0 acyl chains by remodeling reactions involving Cst26p. PE may undergo turnover by the phospholipid: diacylglycerol acyltransferase Lro1p as first step in acyl chain remodeling. Clues as to the functions of phospholipid acyl chain remodeling are discussed.
Topics: Acylation; Animals; Endoplasmic Reticulum; Humans; Phosphatidylcholines; Phosphatidylethanolamines; Phosphatidylinositols; Phospholipids; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins
PubMed: 31146038
DOI: 10.1016/j.bbalip.2019.05.006 -
Biochimica Et Biophysica Acta.... Apr 2017It was first discovered in 1992 that P-glycoprotein (Pgp, ABCB1), an ATP binding cassette (ABC) transporter, can transport phospholipids such as phosphatidylcholine,... (Review)
Review
It was first discovered in 1992 that P-glycoprotein (Pgp, ABCB1), an ATP binding cassette (ABC) transporter, can transport phospholipids such as phosphatidylcholine, -ethanolamine and -serine as well as glucosylceramide and glycosphingolipids. Subsequently, many other ABC transporters were identified to act as lipid transporters. For substrate transport by ABC transporters, typically a classic, alternating access model with an ATP-dependent conformational switch between a high and a low affinity substrate binding site is evoked. Transport of small hydrophilic substrates can easily be imagined this way, as the molecule can in principle enter and exit the transporter in the same orientation. Lipids on the other hand need to undergo a 180° degree turn as they translocate from one membrane leaflet to the other. Lipids and lipidated molecules are highly diverse, so there may be various ways how to achieve their flipping and flopping. Nonetheless, an increase in biophysical, biochemical and structural data is beginning to shed some light on specific aspects of lipid transport by ABC transporters. In addition, there is now abundant evidence that lipids affect ABC transporter conformation, dynamics as well as transport and ATPase activity in general. In this review, we will discuss different ways in which lipids and ABC transporters interact and how lipid translocation may be achieved with a focus on the techniques used to investigate these processes. This article is part of a Special Issue entitled: Lipid order/lipid defects and lipid-control of protein activity edited by Dirk Schneider.
Topics: ATP Binding Cassette Transporter, Subfamily B; Binding Sites; Biological Transport; Fatty Acids; Gene Expression; Humans; Models, Molecular; Phosphatidylcholines; Phosphatidylethanolamines; Phosphatidylserines; Protein Binding; Protein Isoforms; Substrate Specificity
PubMed: 27693344
DOI: 10.1016/j.bbamem.2016.09.023 -
Annual Review of Biochemistry 2009The topology of polytopic membrane proteins is determined by topogenic sequences in the protein, protein-translocon interactions, and interactions during folding within... (Review)
Review
The topology of polytopic membrane proteins is determined by topogenic sequences in the protein, protein-translocon interactions, and interactions during folding within the protein and between the protein and the lipid environment. Orientation of transmembrane domains is dependent on membrane phospholipid composition during initial assembly as well as on changes in lipid composition postassembly. The membrane translocation potential of negative amino acids working in opposition to the positive-inside rule is largely dampened by the normal presence of phosphatidylethanolamine, thus explaining the dominance of positive residues as retention signals. Phosphatidylethanolamine provides the appropriate charge density that permits the membrane surface to maintain a charge balance between membrane translocation and retention signals and also allows the presence of negative residues in the cytoplasmic face of proteins for other purposes.
Topics: Bacteria; Membrane Lipids; Membrane Proteins; Phosphatidylethanolamines; Protein Folding
PubMed: 19489728
DOI: 10.1146/annurev.biochem.77.060806.091251 -
Biochimica Et Biophysica Acta May 2016The bacterial membrane provides a target for antimicrobial peptides. There are two groups of bacteria that have characteristically different surface membranes. One is... (Review)
Review
The bacterial membrane provides a target for antimicrobial peptides. There are two groups of bacteria that have characteristically different surface membranes. One is the Gram-negative bacteria that have an outer membrane rich in lipopolysaccharide. Several antimicrobials have been found to inhibit the synthesis of this lipid, and it is expected that more will be developed. In addition, antimicrobial peptides can bind to the outer membrane of Gram-negative bacteria and block passage of solutes between the periplasm and the cell exterior, resulting in bacterial toxicity. In Gram-positive bacteria, the major bacterial lipid component, phosphatidylglycerol can be chemically modified by bacterial enzymes to convert the lipid from anionic to cationic or zwitterionic form. This process leads to increased levels of resistance of the bacteria against polycationic antimicrobial agents. Inhibitors of this enzyme would provide protection against the development of bacterial resistance. There are antimicrobial agents that directly target a component of bacterial cytoplasmic membranes that can act on both Gram-negative as well as Gram-positive bacteria. Many of these are cyclic peptides with a rigid binding site capable of binding a lipid component. This binding targets antimicrobial agents to bacteria, rather than being toxic to host cells. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert.
Topics: Anti-Bacterial Agents; Antimicrobial Cationic Peptides; Cardiolipins; Cell Membrane; Cell Membrane Permeability; Gram-Negative Bacteria; Gram-Positive Bacteria; Lipid A; Lipopolysaccharides; Molecular Targeted Therapy; Phosphatidylethanolamines; Species Specificity
PubMed: 26514603
DOI: 10.1016/j.bbamem.2015.10.018