scholarly journals Acyl-chain saturation regulates the order of phosphatidylinositol 4,5-bisphosphate nanodomains

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Luís Borges-Araújo ◽  
Marco M. Domingues ◽  
Alexander Fedorov ◽  
Nuno C. Santos ◽  
Manuel N. Melo ◽  
...  
Keyword(s):  
Negative Curvature ◽  
Acyl Chain ◽  
Critical Role ◽  
Chain Structure ◽  
Membrane Remodeling ◽  
Biophysical Properties ◽  
Chain Composition ◽  
Acyl Chain Composition ◽  
Acyl Chains ◽  
The Impact

AbstractPhosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) plays a critical role in the regulation of various plasma membrane processes and signaling pathways in eukaryotes. A significant amount of cellular resources are spent on maintaining the dominant 1-stearoyl-2-arachidonyl PI(4,5)P2 acyl-chain composition, while less abundant and more saturated species become more prevalent in response to specific stimuli, stress or aging. Here, we report the impact of acyl-chain structure on the biophysical properties of cation-induced PI(4,5)P2 nanodomains. PI(4,5)P2 species with increasing levels of acyl-chain saturation cluster in progressively more ordered nanodomains, culminating in the formation of gel-like nanodomains for fully saturated species. The formation of these gel-like domains was largely abrogated in the presence of 1-stearoyl-2-arachidonyl PI(4,5)P2. This is, to the best of our knowledge, the first report of the impact of PI(4,5)P2 acyl-chain composition on cation-dependent nanodomain ordering, and provides important clues to the motives behind the enrichment of PI(4,5)P2 with polyunsaturated acyl-chains. We also show how Ca2+-induced PI(4,5)P2 nanodomains are able to generate local negative curvature, a phenomenon likely to play a role in membrane remodeling events.

scholarly journals Structural Characterization of Natural Yeast Phosphatidylcholine and Bacterial Phosphatidylglycerol Lipid Multilayers by Neutron Diffraction

2021 ◽  
Vol 9 ◽  
Author(s):  
Alessandra Luchini ◽  
Giacomo Corucci ◽  
Krishna Chaithanya Batchu ◽  
Valerie Laux ◽  
Michael Haertlein ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Acyl Chain ◽  
Model Systems ◽  
Head Group ◽  
Single Class ◽  
Lipid Mixtures ◽  
Chain Composition ◽  
Acyl Chain Composition ◽  
The Impact

Eukaryotic and prokaryotic cell membranes are difficult to characterize directly with biophysical methods. Membrane model systems, that include fewer molecular species, are therefore often used to reproduce their fundamental chemical and physical properties. In this context, natural lipid mixtures directly extracted from cells are a valuable resource to produce advanced models of biological membranes for biophysical investigations and for the development of drug testing platforms. In this study we focused on single phospholipid classes, i.e. Pichia pastoris phosphatidylcholine (PC) and Escherichia coli phosphatidylglycerol (PG) lipids. These lipids were characterized by a different distribution of their respective acyl chain lengths and number of unsaturations. We produced both hydrogenous and deuterated lipid mixtures. Neutron diffraction experiments at different relative humidities were performed to characterize multilayers from these lipids and investigate the impact of the acyl chain composition on the structural organization. The novelty of this work resides in the use of natural extracts with a single class head-group and a mixture of chain compositions coming from yeast or bacterial cells. The characterization of the PC and PG multilayers showed that, as a consequence of the heterogeneity of their acyl chain composition, different lamellar phases are formed.

scholarly journals Depletion of Phosphatidylcholine in Yeast Induces Shortening and Increased Saturation of the Lipid Acyl Chains: Evidence for Regulation of Intrinsic Membrane Curvature in a Eukaryote

2006 ◽  
Vol 17 (2) ◽  
pp. 1006-1017 ◽  
Author(s):  
Henry A. Boumann ◽  
Jacob Gubbens ◽  
Martijn C. Koorengevel ◽  
Chan-Seok Oh ◽  
Charles E. Martin ◽  
...  
Keyword(s):  
Regulatory Mechanism ◽  
Lipid Fraction ◽  
Acyl Chain ◽  
Membrane Curvature ◽  
Degree Of Saturation ◽  
Optimal Range ◽  
Double Deletion ◽  
Chain Composition ◽  
Acyl Chain Composition ◽  
Acyl Chains

To study the consequences of depleting the major membrane phospholipid phosphatidylcholine (PC), exponentially growing cells of a yeast cho2opi3 double deletion mutant were transferred from medium containing choline to choline-free medium. Cell growth did not cease until the PC level had dropped below 2% of total phospholipids after four to five generations. Increasing contents of phosphatidylethanolamine (PE) and phosphatidylinositol made up for the loss of PC. During PC depletion, the remaining PC was subject to acyl chain remodeling with monounsaturated species replacing diunsaturated species, as shown by mass spectrometry. The remodeling of PC did not require turnover by the SPO14-encoded phospholipase D. The changes in the PC species profile were found to reflect an overall shift in the cellular acyl chain composition that exhibited a 40% increase in the ratio of C16 over C18 acyl chains, and a 10% increase in the degree of saturation. The shift was stronger in the phospholipid than in the neutral lipid fraction and strongest in the species profile of PE. The shortening and increased saturation of the PE acyl chains were shown to decrease the nonbilayer propensity of PE. The results point to a regulatory mechanism in yeast that maintains intrinsic membrane curvature in an optimal range.

scholarly journals How is the acyl chain composition of phosphoinositides created and does it matter?

2019 ◽  
Vol 47 (5) ◽  
pp. 1291-1305 ◽  
Author(s):  
David Barneda ◽  
Sabina Cosulich ◽  
Len Stephens ◽  
Phillip Hawkins
Keyword(s):  
Cell Biology ◽  
Acyl Chain ◽  
Effector Proteins ◽  
Selective Enrichment ◽  
Binding Domains ◽  
Chain Composition ◽  
Acyl Chain Composition ◽  
Phosphorylation Pattern ◽  
Acyl Chains ◽  
Membrane Cell

Abstract The phosphoinositide (PIPn) family of signalling phospholipids are central regulators in membrane cell biology. Their varied functions are based on the phosphorylation pattern of their inositol ring, which can be recognized by selective binding domains in their effector proteins and be modified by a series of specific PIPn kinases and phosphatases, which control their interconversion in a spatial and temporal manner. Yet, a unique feature of PIPns remains largely unexplored: their unusually uniform acyl chain composition. Indeed, while most phospholipids present a range of molecular species comprising acyl chains of diverse length and saturation, PIPns in several organisms and tissues show the predominance of a single hydrophobic backbone, which in mammals is composed of arachidonoyl and stearoyl chains. Despite evolution having favoured this specific PIPn configuration, little is known regarding the mechanisms and functions behind it. In this review, we explore the metabolic pathways that could control the acyl chain composition of PIPns as well as the potential roles of this selective enrichment. While our understanding of this phenomenon has been constrained largely by the technical limitations in the methods traditionally employed in the PIPn field, we believe that the latest developments in PIPn analysis should shed light onto this old question.

scholarly journals Sphingomyelin Interfacial Behavior: The Impact of Changing Acyl Chain Composition

2000 ◽  
Vol 78 (4) ◽  
pp. 1921-1931 ◽  
Author(s):  
Xin-Min Li ◽  
Janice M. Smaby ◽  
Maureen M. Momsen ◽  
Howard L. Brockman ◽  
Rhoderick E. Brown
Keyword(s):  
Acyl Chain ◽  
Interfacial Behavior ◽  
Chain Composition ◽  
Acyl Chain Composition ◽  
The Impact

scholarly journals Four Acyltransferases Uniquely Contribute to Phospholipid Heterogeneity in Saccharomyces cerevisiae

2016 ◽  
Vol 9 ◽  
pp. LPI.S40597 ◽  
Author(s):  
Peter Oelkers ◽  
Keshav Pokhrel
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acyl Chain ◽  
Wild Type ◽  
Acid Incorporation ◽  
Rich Media ◽  
Chain Composition ◽  
Acyl Chain Composition ◽  
Acyl Chains ◽  
Phospholipid Acyl Chain

Diverse acyl-CoA species and acyltransferase isoenzymes are components of a complex system that synthesizes glycerophospholipids and triacylglycerols. Saccharomyces cerevisiae has four main acyl-CoA species, two main glycerol-3-phosphate 1- O-acyltransferases (Gat1p, Gat2p), and two main 1-acylglycerol-3-phosphate O-acyltransferases (Lpt1p, Slc1p). The in vivo contribution of these isoenzymes to phospholipid heterogeneity was determined using haploids with compound mutations: gat1Δlpt1Δ, gat2Δlpt1Δ, gat1Δslc1Δ, and gat2Δslc1Δ. All mutations mildly reduced [3H]palmitic acid incorporation into phospholipids relative to triacylglycerol. Electrospray ionization tandem mass spectrometry identified few differences from wild type in gat1Δlpt1Δ, dramatic differences in gat2Δslc1Δ, and intermediate changes in gat2Δlpt1Δ and gat1Δslc1Δ. Yeast expressing Gat1p and Lpt1p had phospholipids enriched with acyl chains that were unsaturated, 18 carbons long, and paired for length. These alterations prevented growth at 18.5°C and in 10% ethanol. Therefore, Gat2p and Slc1p dictate phospholipid acyl chain composition in rich media at 30°C. Slc1p selectively pairs acyl chains of different lengths.

scholarly journals Unremodeled and Remodeled Cardiolipin Are Functionally Indistinguishable in Yeast

2013 ◽  
Vol 289 (3) ◽  
pp. 1768-1778 ◽  
Author(s):  
Matthew G. Baile ◽  
Murugappan Sathappa ◽  
Ya-Wen Lu ◽  
Erin Pryce ◽  
Kevin Whited ◽  
...  
Keyword(s):  
Molecular Form ◽  
Acyl Chain ◽  
Barth Syndrome ◽  
Molecular Forms ◽  
Mitochondrial Morphology ◽  
Causative Gene ◽  
Chain Composition ◽  
Acyl Chain Composition ◽  
Acyl Chains ◽  
Functional Capacities

After biosynthesis, an evolutionarily conserved acyl chain remodeling process generates a final highly homogeneous and yet tissue-specific molecular form of the mitochondrial lipid cardiolipin. Hence, cardiolipin molecules in different organisms, and even different tissues within the same organism, contain a distinct collection of attached acyl chains. This observation is the basis for the widely accepted paradigm that the acyl chain composition of cardiolipin is matched to the unique mitochondrial demands of a tissue. For this hypothesis to be correct, cardiolipin molecules with different acyl chain compositions should have distinct functional capacities, and cardiolipin that has been remodeled should promote cardiolipin-dependent mitochondrial processes better than its unremodeled form. However, functional disparities between different molecular forms of cardiolipin have never been established. Here, we interrogate this simple but crucial prediction utilizing the best available model to do so, Saccharomyces cerevisiae. Specifically, we compare the ability of unremodeled and remodeled cardiolipin, which differ markedly in their acyl chain composition, to support mitochondrial activities known to require cardiolipin. Surprisingly, defined changes in the acyl chain composition of cardiolipin do not alter either mitochondrial morphology or oxidative phosphorylation. Importantly, preventing cardiolipin remodeling initiation in yeast lacking TAZ1, an ortholog of the causative gene in Barth syndrome, ameliorates mitochondrial dysfunction. Thus, our data do not support the prevailing hypothesis that unremodeled cardiolipin is functionally distinct from remodeled cardiolipin, at least for the functions examined, suggesting alternative physiological roles for this conserved pathway.

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