Unsaturated acyl chains dramatically enhanced cellular uptake by direct translocation of a minimalist oligo-arginine lipopeptide

2015 ◽  
Vol 51 (78) ◽  
pp. 14656-14659 ◽  
Author(s):  
J.-M. Swiecicki ◽  
M. Di Pisa ◽  
F. Lippi ◽  
S. Chwetzoff ◽  
C. Mansuy ◽  
...  

Unsaturated acyl chain favours direct translocation of short cationic NBD-labelled peptide.

2015 ◽  
Vol 89 (15) ◽  
pp. 7861-7873 ◽  
Author(s):  
Balaji Olety ◽  
Sarah L. Veatch ◽  
Akira Ono

ABSTRACTHIV-1 Gag, which drives virion assembly, interacts with a plasma membrane (PM)-specific phosphoinositide, phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2]. While cellular acidic phospholipid-binding proteins/domains, such as the PI(4,5)P2-specific pleckstrin homology domain of phospholipase Cδ1 (PHPLCδ1), mediate headgroup-specific interactions with corresponding phospholipids, the exact nature of the Gag-PI(4,5)P2interaction remains undetermined. In this study, we used giant unilamellar vesicles (GUVs) to examine how PI(4,5)P2with unsaturated or saturated acyl chains affect membrane binding of PHPLCδ1and Gag. Both unsaturated dioleoyl-PI(4,5)P2[DO-PI(4,5)P2] and saturated dipalmitoyl-PI(4,5)P2[DP-PI(4,5)P2] successfully recruited PHPLCδ1to membranes of single-phase GUVs. In contrast, DO-PI(4,5)P2but not DP-PI(4,5)P2recruited Gag to GUVs, indicating that PI(4,5)P2acyl chains contribute to stable membrane binding of Gag. GUVs containing PI(4,5)P2, cholesterol, and dipalmitoyl phosphatidylserine separated into two coexisting phases: one was a liquid phase, and the other appeared to be a phosphatidylserine-enriched gel phase. In these vesicles, the liquid phase recruited PHPLCδ1regardless of PI(4,5)P2acyl chains. Likewise, Gag bound to the liquid phase when PI(4,5)P2had DO-acyl chains. DP-PI(4,5)P2-containing GUVs showed no detectable Gag binding to the liquid phase. Unexpectedly, however, DP-PI(4,5)P2still promoted recruitment of Gag, but not PHPLCδ1, to the dipalmitoyl-phosphatidylserine-enriched gel phase of these GUVs. Altogether, these results revealed different roles for PI(4,5)P2acyl chains in membrane binding of two PI(4,5)P2-binding proteins, Gag and PHPLCδ1. Notably, we observed that nonmyristylated Gag retains the preference for PI(4,5)P2containing an unsaturated acyl chain over DP-PI(4,5)P2, suggesting that Gag sensitivity to PI(4,5)P2acyl chain saturation is determined directly by the matrix-PI(4,5)P2interaction, rather than indirectly by a myristate-dependent mechanism.IMPORTANCEBinding of HIV-1 Gag to the plasma membrane is promoted by its interaction with a plasma membrane-localized phospholipid, PI(4,5)P2. Many cellular proteins are also recruited to the plasma membrane via PI(4,5)P2-interacting domains represented by PHPLCδ1. However, differences and/or similarities between these host proteins and viral Gag protein in the nature of their PI(4,5)P2interactions, especially in the context of membrane binding, remain to be determined. Using a novel giant unilamellar vesicle-based system, we found that PI(4,5)P2with an unsaturated acyl chain recruited PHPLCδ1and Gag similarly, whereas PI(4,5)P2with saturated acyl chains either recruited PHPLCδ1but not Gag or sorted these proteins to different phases of vesicles. To our knowledge, this is the first study to show that PI(4,5)P2acyl chains differentially modulate membrane binding of PI(4,5)P2-binding proteins. Since Gag membrane binding is essential for progeny virion production, the PI(4,5)P2acyl chain property may serve as a potential target for anti-HIV therapeutic strategies.


2001 ◽  
Vol 183 (12) ◽  
pp. 3721-3728 ◽  
Author(s):  
Véréna Poinsot ◽  
Elaine Bélanger ◽  
Serge Laberge ◽  
Guo-Ping Yang ◽  
Hani Antoun ◽  
...  

ABSTRACT Mesorhizobium sp. strain N33 (Oxytropis arctobia), a rhizobial strain isolated in arctic Canada, is able to fix nitrogen at very low temperatures in association with a few arctic legume species belonging to the genera Astragalus, Onobrychis, and Oxytropis. Using mass spectrometry and nuclear magnetic resonance spectroscopy, we have determined the structure of N33 Nod factors, which are major determinants of nodulation. They are pentameric lipochito-oligosaccharides 6-O sulfated at the reducing end and exhibit other original substitutions: 6-O acetylation of the glucosamine residue next to the nonreducing terminal glucosamine and N acylation of the nonreducing terminal glucosamine by methyl-branched acyl chains of the iso series, some of which are α,β unsaturated. These unusual substitutions may contribute to the peculiar host range of N33. Analysis of N33 whole-cell fatty acids indicated that synthesis of the methyl-branched fatty acids depended on the induction of bacteria by plant flavonoids, suggesting a specific role for these fatty acids in the signaling process between the plant and the bacteria. Synthesis of the methyl-branched α,β-unsaturated fatty acids required a functional nodE gene.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Claudia Di Carlo ◽  
Bebiana C. Sousa ◽  
Marcello Manfredi ◽  
Jessica Brandi ◽  
Elisa Dalla Pozza ◽  
...  

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.


2015 ◽  
Vol 8s1 ◽  
pp. LPI.S31780 ◽  
Author(s):  
Mike F. Renne ◽  
Xue Bao ◽  
Cedric H. De Smet ◽  
Anton I. P. M. De Kroon

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.


2011 ◽  
Vol 64 (6) ◽  
pp. 798 ◽  
Author(s):  
David I. Fernandez ◽  
Marc-Antoine Sani ◽  
Frances Separovic

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.


2021 ◽  
Author(s):  
Stefanie S. Schmieder ◽  
Raju Tatituri ◽  
Michael Anderson ◽  
Kate Kelly ◽  
Wayne I. Lencer

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.


2021 ◽  
Author(s):  
Zhipeng Chen ◽  
Da Xu ◽  
Liang Wang ◽  
Cong-Zhao Zhou ◽  
Wen-Tao Hou ◽  
...  

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.


1994 ◽  
Vol 301 (2) ◽  
pp. 455-458 ◽  
Author(s):  
R Sundler ◽  
D Winstedt ◽  
J Wijkander

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.


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