scholarly journals Structural basis for acyl chain control over glycosphingolipid sorting and vesicular trafficking

2021 ◽  
Author(s):  
Stefanie S. Schmieder ◽  
Raju Tatituri ◽  
Michael Anderson ◽  
Kate Kelly ◽  
Wayne I. Lencer
Keyword(s):  
Acyl Chain ◽  
Vesicular Trafficking ◽  
Structural Motif ◽  
Structural Basis ◽  
Membrane Organization ◽  
Endosomal Sorting ◽  
Lysosomal Sorting ◽  
Acyl Chains ◽  
Complex Sphingolipids ◽  
Endocytic Pathways

AbstractThe complex sphingolipids exhibit a diversity of ceramide acyl chain structures that influence their trafficking and intracellular distributions, but how the cell discerns among the different ceramides to affect such sorting remains unknown. To address mechanism, we synthesized a library of GM1 glycosphingolipids with naturally varied acyl chains and quantitatively assessed their sorting among different endocytic pathways. We found that a stretch of at least 14 saturated carbons extending from C1 at the water-bilayer interface dictated lysosomal sorting by exclusion from endosome sorting tubules. Sorting to the lysosome by the C14*-motif was cholesterol dependent. Perturbations of the C14*-motif by unsaturation enabled GM1 entry into endosomal sorting tubules of the recycling and retrograde pathways independently of cholesterol. Unsaturation occurring beyond the C14*-motif in very long acyl chains rescued lysosomal sorting. These results define a structural motif underlying membrane organization of sphingolipids and implicate cholesterol-sphingolipid nanodomain formation in sorting mechanisms.

scholarly journals Structural basis of substrate recognition and translocation by human ABCD1

2021 ◽  
Author(s):  
Zhipeng Chen ◽  
Da Xu ◽  
Liang Wang ◽  
Cong-Zhao Zhou ◽  
Wen-Tao Hou ◽  
...  
Keyword(s):  
Genetic Disorder ◽  
Substrate Recognition ◽  
Acyl Chain ◽  
Chain Fatty Acid ◽  
Structural Basis ◽  
Long Chain Fatty Acid ◽  
Lateral Entry ◽  
Binding Domains ◽  
Acyl Chains ◽  
Functional States

Human ATP-binding cassette (ABC) subfamily D transporter ABCD1 can transport CoA esters of saturated/monounsaturated long/very long chain fatty acid into the peroxisome for β-oxidation. Dysfunction of human ABCD1 causes X-linked adrenoleukodystrophy, which is a severe progressive genetic disorder affecting the nervous system. Nevertheless, the mechanistic details of substrate recognition and translocation by ABCD1 remains obscure. Here, we present three cryo-EM structures of human ABCD1 in distinct functional states. In the apo-form structure of 3.53 Å resolution, ABCD1 exhibits an inward-facing conformation, allowing the lateral entry of substrate from the lipid bilayer. In the 3.59 Å structure of substrate-bound ABCD1, two molecules of C22:0-CoA, the physiological substrate of ABCD1, is symmetrically bound in two transmembrane domains (TMDs). Each C22:0-CoA adopts a L-shape, with its CoA portion and acyl chain components bound to two TMDs respectively, resembling a pair of strings that pull the TMDs closer, resultantly generating a narrower outward-facing conformation. In the 2.79 Å ATP-bound ABCD1 structure, the two nucleotide-binding domains dimerize, leading to an outward-facing conformation, which opens the translocation cavity exit towards the peroxisome matrix side and releases the substrates. Our study provides a molecular basis to understand the mechanism of ABCD1-mediated substrate recognition and translocation, and suggests a unique binding pattern for amphipathic molecules with long acyl chains.

scholarly journals Caveolin-1 and cavin1 act synergistically to generate a unique lipid environment in caveolae

2021 ◽  
Vol 220 (3) ◽  
Author(s):  
Yong Zhou ◽  
Nicholas Ariotti ◽  
James Rae ◽  
Hong Liang ◽  
Vikas Tillu ◽  
...  
Keyword(s):  
Lipid Profile ◽  
Membrane Lipids ◽  
Acyl Chain ◽  
Vesicular Trafficking ◽  
Dynamic Simulations ◽  
Caveolin 1 ◽  
Vertebrate Cell ◽  
Lipid Sorting ◽  
Acyl Chains ◽  
Lipid Environment

Caveolae are specialized domains of the vertebrate cell surface with a well-defined morphology and crucial roles in cell migration and mechanoprotection. Unique compositions of proteins and lipids determine membrane architectures. The precise caveolar lipid profile and the roles of the major caveolar structural proteins, caveolins and cavins, in selectively sorting lipids have not been defined. Here, we used quantitative nanoscale lipid mapping together with molecular dynamic simulations to define the caveolar lipid profile. We show that caveolin-1 (CAV1) and cavin1 individually sort distinct plasma membrane lipids. Intact caveolar structures composed of both CAV1 and cavin1 further generate a unique lipid nano-environment. The caveolar lipid sorting capability includes selectivities for lipid headgroups and acyl chains. Because lipid headgroup metabolism and acyl chain remodeling are tightly regulated, this selective lipid sorting may allow caveolae to act as transit hubs to direct communications among lipid metabolism, vesicular trafficking, and signaling.

scholarly journals Dissecting the nanoscale lipid profile of caveolae

2020 ◽  
Author(s):  
Yong Zhou ◽  
Nicholas Ariotti ◽  
James Rae ◽  
Hong Liang ◽  
Vikas Tillu ◽  
...  
Keyword(s):  
Lipid Profile ◽  
Membrane Lipids ◽  
Acyl Chain ◽  
Vesicular Trafficking ◽  
Structural Proteins ◽  
Dynamic Simulations ◽  
Vertebrate Cell ◽  
Lipid Sorting ◽  
Acyl Chains ◽  
Direct Communications

AbstractCaveolae are specialized domains of the vertebrate cell surface with a well-defined morphology and crucial roles in cell migration and mechanoprotection. Unique compositions of proteins and lipids determine membrane architectures. The precise caveolar lipid profile and the roles of the major caveolar structural proteins, caveolins and cavins, in selectively sorting lipids have not been defined. Here we used quantitative nanoscale lipid mapping together with molecular dynamic simulations to define the caveolar lipid profile. We show that caveolin1 (CAV1) and cavin1 individually sort distinct plasma membrane lipids. Intact caveolar structures composed of both CAV1 and cavin1 further generate a unique lipid nano-environment. The caveolar lipid sorting capability includes selectivities for lipid headgroups and acyl chains. Because lipid headgroup metabolism and acyl chain remodelling are tightly regulated, this selective lipid sorting may allow caveolae to act as transit hubs to direct communications among lipid metabolism, vesicular trafficking and signalling.

scholarly journals Integrated lipidomics and proteomics reveal cardiolipin alterations, upregulation of HADHA and long chain fatty acids in pancreatic cancer stem cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Claudia Di Carlo ◽  
Bebiana C. Sousa ◽  
Marcello Manfredi ◽  
Jessica Brandi ◽  
Elisa Dalla Pozza ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Stem Cells ◽  
Fatty Acid ◽  
Cancer Stem Cells ◽  
Acyl Chain ◽  
Fatty Acid Elongase ◽  
Acyl Chains ◽  
A Chain ◽  
Pancreatic Cancer Stem Cells ◽  
Long Chain

AbstractPancreatic cancer stem cells (PCSCs) play a key role in the aggressiveness of pancreatic ductal adenocarcinomas (PDAC); however, little is known about their signaling and metabolic pathways. Here we show that PCSCs have specific and common proteome and lipidome modulations. PCSCs displayed downregulation of lactate dehydrogenase A chain, and upregulation of trifunctional enzyme subunit alpha. The upregulated proteins of PCSCs are mainly involved in fatty acid (FA) elongation and biosynthesis of unsaturated FAs. Accordingly, lipidomics reveals an increase in long and very long-chain unsaturated FAs, which are products of fatty acid elongase-5 predicted as a key gene. Moreover, lipidomics showed the induction in PCSCs of molecular species of cardiolipin with mixed incorporation of 16:0, 18:1, and 18:2 acyl chains. Our data indicate a crucial role of FA elongation and alteration in cardiolipin acyl chain composition in PCSCs, representing attractive therapeutic targets in PDAC.

scholarly journals Lipid Acyl Chain Remodeling in Yeast

2015 ◽  
Vol 8s1 ◽  
pp. LPI.S31780 ◽  
Author(s):  
Mike F. Renne ◽  
Xue Bao ◽  
Cedric H. De Smet ◽  
Anton I. P. M. De Kroon
Keyword(s):  
Intracellular Transport ◽  
De Novo ◽  
Acyl Chain ◽  
Model Organism ◽  
Lipid Synthesis ◽  
Membrane Lipid ◽  
Lipid Homeostasis ◽  
Synthetic Process ◽  
Acyl Chains ◽  
Phospholipid Acyl Chain

Membrane lipid homeostasis is maintained by de novo synthesis, intracellular transport, remodeling, and degradation of lipid molecules. Glycerophospholipids, the most abundant structural component of eukaryotic membranes, are subject to acyl chain remodeling, which is defined as the post-synthetic process in which one or both acyl chains are exchanged. Here, we review studies addressing acyl chain remodeling of membrane glycerophospholipids in Saccharomyces cerevisiae, a model organism that has been successfully used to investigate lipid synthesis and its regulation. Experimental evidence for the occurrence of phospholipid acyl chain exchange in cardiolipin, phosphatidylcholine, phosphatidylinositol, and phosphatidylethanolamine is summarized, including methods and tools that have been used for detecting remodeling. Progress in the identification of the enzymes involved is reported, and putative functions of acyl chain remodeling in yeast are discussed.

Interactions of the Antimicrobial Peptide Maculatin 1.1 and Analogues with Phospholipid Bilayers

2011 ◽  
Vol 64 (6) ◽  
pp. 798 ◽  
Author(s):  
David I. Fernandez ◽  
Marc-Antoine Sani ◽  
Frances Separovic
Keyword(s):  
Antimicrobial Peptide ◽  
Solid State Nmr ◽  
Acyl Chain ◽  
Head Group ◽  
Group Interactions ◽  
Bacterial Membranes ◽  
Helical Content ◽  
Lipid System ◽  
Acyl Chains ◽  
Mixed Bilayer

The interactions of the antimicrobial peptide, maculatin 1.1 (GLFGVLAKVAAHVVPAIAEHF-NH2) and two analogues, with model phospholipid membranes have been studied using solid-state NMR and circular dichroism spectroscopy. Maculatin 1.1 and the P15G and P15A analogues displayed minimal secondary structure in water, but with zwitterionic dimyristoylphosphatidylcholine (DMPC) vesicles displayed a significant increase in α-helical content. In mixed phospholipid vesicles of DMPC and anionic dimyristoylphosphatidylglycerol (DMPG), each peptide was highly structured with ~80% α-helical content. In DMPC vesicles, the native peptide displayed moderate head group interaction and significant perturbation of the lipid acyl chains. In DMPC/DMPG vesicles, maculatin 1.1 promoted formation of a DMPG-enriched phase and moderately increased disorder towards acyl chain ends of DMPC in the mixed bilayer. Both analogues showed reduced phospholipid head group interactions with DMPC but displayed significant interactions with the mixed lipid system. These effects support the preferential activity of these antimicrobial peptides for bacterial membranes.

scholarly journals Acyl-chain selectivity of the 85 kDa phospholipase A2 and of the release process in intact macrophages

1994 ◽  
Vol 301 (2) ◽  
pp. 455-458 ◽  
Author(s):  
R Sundler ◽  
D Winstedt ◽  
J Wijkander
Keyword(s):  
Phospholipase A2 ◽  
Acyl Chain ◽  
Calcium Ionophore ◽  
Release Process ◽  
In Vitro System ◽  
Acyl Chain Length ◽  
Mouse Macrophages ◽  
J774 Cells ◽  
Acyl Chains

The selectivity of the intracellular 85 kDa phospholipase A2 (PLA2-85) towards fatty acids closely related to arachidonic acid has been investigated, using purified PLA2-85 from J774 cells and mixed phospholipids, dually acyl-chain-labelled in the sn-2 position. In parallel experiments, we assessed the acyl-chain selectivity of the release process in intact, dually labelled, peritoneal mouse macrophages responding to either calcium ionophore or zymosan beads in the presence of indomethacin and BSA. The results obtained in the two systems were very similar, which supports previous evidence that PLA2-85 is responsible for stimulus-induced release of eicosanoid precursor in mouse macrophages. In the in vitro system, PLA2-85 was found to exhibit a moderate selectivity towards C20 acyl chains differing in double-bond structure, while the sensitivity to acyl-chain length was more pronounced. Together with previous data, these results demonstrate a striking preference for C20 over either C18 or C22 unsaturated acyl chains.

scholarly journals The contributions of biosynthesis and acyl chain remodelling to the molecular species profile of phosphatidylcholine in yeast

2005 ◽  
Vol 33 (5) ◽  
pp. 1146-1149 ◽  
Author(s):  
H.A. Boumann ◽  
A.I.P.M. de Kroon
Keyword(s):  
Stable Isotope ◽  
Species Composition ◽  
Molecular Species ◽  
Acyl Chain ◽  
Membrane Lipid ◽  
Molecular Species Composition ◽  
Stable Isotope Labelling ◽  
Membrane Function ◽  
Isotope Labelling ◽  
Acyl Chains

Phosphatidylcholine (PC) is a very abundant membrane lipid in most eukaryotes, including yeast. The molecular species profile of PC, i.e. the ensemble of PC molecules with acyl chains differing in number of carbon atoms and double bonds, is important for membrane function. Pathways of PC synthesis and turnover maintain PC homoeostasis and determine the molecular species profile of PC. Studies addressing the processes involved in establishing the molecular species composition of PC in yeast using stable isotope labelling combined with detection by MS are reviewed.

scholarly journals Acyltransferase-mediated selection of the length of the fatty acyl chain and of the acylation site governs activation of bacterial RTX toxins

2020 ◽  
Vol 295 (28) ◽  
pp. 9268-9280 ◽  
Author(s):  
Adriana Osickova ◽  
Humaira Khaliq ◽  
Jiri Masin ◽  
David Jurnecka ◽  
Anna Sukova ◽  
...  
Keyword(s):  
Acyl Chain ◽  
Fatty Acyl ◽  
Biologically Active ◽  
Fatty Acyl Chain ◽  
Acyl Carrier Proteins ◽  
E Coli ◽  
Rtx Toxins ◽  
Wide Range ◽  
Lysine Residues ◽  
Acyl Chains

In a wide range of organisms, from bacteria to humans, numerous proteins have to be posttranslationally acylated to become biologically active. Bacterial repeats in toxin (RTX) cytolysins form a prominent group of proteins that are synthesized as inactive protoxins and undergo posttranslational acylation on ε-amino groups of two internal conserved lysine residues by co-expressed toxin-activating acyltransferases. Here, we investigated how the chemical nature, position, and number of bound acyl chains govern the activities of Bordetella pertussis adenylate cyclase toxin (CyaA), Escherichia coli α-hemolysin (HlyA), and Kingella kingae cytotoxin (RtxA). We found that the three protoxins are acylated in the same E. coli cell background by each of the CyaC, HlyC, and RtxC acyltransferases. We also noted that the acyltransferase selects from the bacterial pool of acyl–acyl carrier proteins (ACPs) an acyl chain of a specific length for covalent linkage to the protoxin. The acyltransferase also selects whether both or only one of two conserved lysine residues of the protoxin will be posttranslationally acylated. Functional assays revealed that RtxA has to be modified by 14-carbon fatty acyl chains to be biologically active, that HlyA remains active also when modified by 16-carbon acyl chains, and that CyaA is activated exclusively by 16-carbon acyl chains. These results suggest that the RTX toxin molecules are structurally adapted to the length of the acyl chains used for modification of their acylated lysine residue in the second, more conserved acylation site.

scholarly journals Identification of unusual phospholipids from bovine heart mitochondria by HPLC-MS/MS

2020 ◽  
Vol 61 (12) ◽  
pp. 1707-1719
Author(s):  
Junhwan Kim ◽  
Charles L. Hoppel
Keyword(s):  
Acyl Chain ◽  
Heart Mitochondria ◽  
Ether Linkage ◽  
Molecular Weights ◽  
Bovine Heart ◽  
Class Separation ◽  
Normal Phase Hplc ◽  
Acyl Chains ◽  
Clear Identification ◽  
Fragmentation Patterns

Phospholipids, including ether phospholipids, are composed of numerous isomeric and isobaric species that have the same backbone and acyl chains. This structural resemblance results in similar fragmentation patterns by collision-induced dissociation of phospholipids regardless of class, yielding complicated MS/MS spectra when isobaric species are analyzed together. Furthermore, the presence of isobaric species can lead to misassignment of species when made solely based on their molecular weights. In this study, we used normal-phase HPLC for ESI-MS/MS analysis of phospholipids from bovine heart mitochondria. Class separation by HPLC eliminates chances for misidentification of isobaric species from different classes of phospholipids. Chromatography yields simple MS/MS spectra without interference from isobaric species, allowing clear identification of peaks corresponding to fragmented ions containing monoacylglycerol backbone derived from losing one acyl chain. Using these fragmented ions, we characterized individual and isomeric species in each class of mitochondrial phospholipids, including unusual species, such as PS, containing an ether linkage and species containing odd-numbered acyl chains in cardiolipin, PS, PI, and PG. We also characterized monolysocardiolipin and dilysocardiolipin, the least abundant but nevertheless important mitochondrial phospholipids. The results clearly show the power of HPLC-MS/MS for identification and characterization of phospholipids, including minor species.

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