Lipid binding to amyloid beta-peptide aggregates: preferential binding of cholesterol as compared with phosphatidylcholine and fatty acids.
AuthorsAvdulov NA, Chochina SV, Igbavboa U, Warden CS, Vassiliev AV, Wood WG
JournalJ Neurochem
PubMed ID9326304
'Amyloid beta-peptide (A beta) aggregates are one of the key neuropathological characteristics of Alzheimer''s disease. A beta belongs to a group of proteins that aggregate and form beta-sheets, and some of these proteins bind cholesterol and other lipids. The purpose of the experiments reported here was to determine if cholesterol, ... More
C(60) and water-soluble fullerene derivatives as antioxidants against radical-initiated lipid peroxidation.
AuthorsWang IC, Tai LA, Lee DD, Kanakamma PP, Shen CK, Luh TY, Cheng CH, Hwang KC
JournalJ Med Chem
PubMed ID10579823
'C(60), vitamin E, and three C(60) derivatives (polar 1 and water-soluble C(3)/D(3)C(60)s) were examined for their antioxidant effects on prevention of lipid peroxidation induced by superoxide and hydroxyl radicals. The protection effect on lipid peroxidation was found to be in the sequence: C(60) >/= vitamin E > 1 > none, ... More
Interaction of the mitochondria-targeted antioxidant MitoQ with phospholipid bilayers and ubiquinone oxidoreductases.
'MitoQ(10) is a ubiquinone that accumulates within mitochondria driven by a conjugated lipophilic triphenylphosphonium cation (TPP(+)). Once there, MitoQ(10) is reduced to its active ubiquinol form, which has been used to prevent mitochondrial oxidative damage and to infer the involvement of reactive oxygen species in signaling pathways. Here we show ... More
Kinetics of fusion between endoplasmic reticulum vesicles in vitro.
AuthorsOrsel JG, Bartoldus I, Stegmann T
JournalJ Biol Chem
PubMed ID9013578
'The endoplasmic reticulum (ER) is a highly dynamic organelle, continuously undergoing membrane fusion and fission. We have measured homotypic fusion between ER vesicles isolated from Chinese hamster ovary cells kinetically in vitro, using an assay based on the metabolic incorporation of pyrene-labeled fatty acids into the phospholipids of cellular membranes. ... More
Membrane fusion of Semliki Forest virus in a model system: correlation between fusion kinetics and structural changes in the envelope glycoprotein.
AuthorsBron R, Wahlberg JM, Garoff H, Wilschut J
JournalEMBO J
PubMed ID8440260
'This paper presents a kinetic analysis of low-pH-induced fusion of Semliki Forest virus (SFV) with cholesterol-containing unilamellar lipid vesicles (liposomes), consisting otherwise of phosphatidylcholine, phosphatidylethanolamine and sphingomyelin. Fusion is monitored continuously with a lipid mixing assay, involving virus bio-synthetically labeled with the fluorophore pyrene. At pH 5.55, 37 degrees C, ... More
Spontaneous transfer of monoacyl amphiphiles between lipid and protein surfaces.
AuthorsMassey JB, Bick DH, Pownall HJ
JournalBiophys J
PubMed ID9083677
'The kinetics of transfer of natural and fluorescent nonesterified fatty acids (NEFA) and lysolecithins (lysoPC) from phospholipid and protein surfaces were measured. The kinetics of transfer of 12-(1-pyrenyl)dodecanoic acid, from liquid crystalline and gel phase single unilamellar phospholipid vesicles, very low, low, and high density lipoproteins, human serum albumin, and ... More
Sphingolipid and cholesterol dependence of alphavirus membrane fusion. Lack of correlation with lipid raft formation in target liposomes.
AuthorsWaarts BL, Bittman R, Wilschut J
JournalJ Biol Chem
PubMed ID12138173
'Semliki Forest virus (SFV) and Sindbis virus (SIN) are enveloped viruses that infect their host cells by receptor-mediated endocytosis and subsequent fusion from within acidic endosomes. Fusion of the viral envelope requires the presence of both cholesterol and sphingolipids in the target membrane. This is suggestive of a possible involvement ... More
Pyrene-labeled lipids: versatile probes of membrane dynamics in vitro and in living cells.
AuthorsPownall HJ, Smith LC
JournalChem Phys Lipids
PubMed ID2670287
Pyrene-labeled analogs of fatty acids have been studied as probes of lipid metabolism in vitro and in cultured cells. Procedures for the synthesis of complex pyrenyl lipids and the analytical methods for their separation and quantification are described. Pyrenyl-lipids have been used to quantify the relationship between lipid structure and ... More
Membrane fusion of Semliki Forest virus involves homotrimers of the fusion protein.
AuthorsWahlberg JM, Bron R, Wilschut J, Garoff H
JournalJ Virol
PubMed ID1433520
Infection of cells with enveloped viruses is accomplished through membrane fusion. The binding and fusion processes are mediated by the spike proteins in the envelope of the virus particle and usually involve a series of conformational changes in these proteins. We have studied the low-pH-mediated fusion process of the alphavirus ... More
Pyrene cholesterol reports the transient appearance of nonlamellar intermediate structures during fusion of model membranes.
AuthorsMalinin VS, Lentz BR
JournalBiochemistry
PubMed ID11980495
We have hypothesized that modulating the free energy of hydrophobic mismatch (HM) might be a principal means to control the fusion process and that it may be a role of cholesterol to counteract HM and make membranes fusogenic. To test these hypotheses, we examined the ability of cholesterol 1-pyrenebutyrate (PY-Ch) ... More
Pyrene phospholipid as a biological fluorescent probe for studying fusion of virus membrane with liposomes.
AuthorsPal R, Barenholz Y, Wagner RR
JournalBiochemistry
PubMed ID2831956
We are using fluorescent endogenous phospholipids in virus membranes to study the factors that promote fusion on interaction with receptor membranes. To this end, vesicular stomatitis virus (VSV) grown in baby hamster kidney (BHK-21) cells was biologically labeled with fluorescent lipids, primarily phosphatidylcholine and phosphatidylethanolamine, derived from pyrene fatty acids. ... More
Effects of fluorophore structure and hydrophobicity on the uptake and metabolism of fluorescent lipid analogs.
AuthorsNaylor BL, Picardo M, Homan R, Pownall HJ
JournalChem Phys Lipids
PubMed ID1934193
Cellular transport and metabolism of fatty acids are integral components of lipid metabolism, but the mechanisms and regulation involved are poorly understood. A variety of commercially available fluorescent analogs of fatty acids, are potentially useful probes for the study of lipid metabolism by such techniques as cell sorting and fluorescence ... More
Evaluation of viral membrane fusion assays. Comparison of the octadecylrhodamine dequenching assay with the pyrene excimer assay.
AuthorsStegmann T, Schoen P, Bron R, Wey J, Bartoldus I, Ortiz A, Nieva JL, Wilschut J
JournalBiochemistry
PubMed ID8218197
Membrane fusion, in particular the fusion of enveloped viruses, is often measured with an assay based on octadecylrhodamine (R18) fluorescence dequenching. We have studied the association of R18 with membranes and used the R18 assay to measure virus fusion in model systems and in cultured cells. The results were compared ... More
Lateral organization of pyrene-labeled lipids in bilayers as determined from the deviation from equilibrium between pyrene monomers and excimers.
AuthorsBarenholz Y, Cohen T, Haas E, Ottolenghi M
JournalJ Biol Chem
PubMed ID8621705
In lipid bilayers, pyrene and pyrene-labeled lipids form excimers in a concentration-dependent manner. The aromatic amine N, N-diethylaniline (DEA), which has a high membrane-to-medium partition coefficient, quenches the monomers only, and therefore it is expected that under conditions in which the monomers are in equilibrium with the excimers due to ... More
Organization and dynamics of pyrene and pyrene lipids in intact lipid bilayers. Photo-induced charge transfer processes.
AuthorsBarenholz Y, Cohen T, Korenstein R, Ottolenghi M
JournalBiophys J
PubMed ID1883931
The dynamics of fluorescence quenching and the organization of a series of pyrene derivatives anchored in various depths in bilayers of phosphatidylcholine small unilamellar vesicles was studied and compared with their behavior in homogeneous solvent systems. The studies include characterization of the environmental polarity of the pyrene fluorophore based on ... More
Spectroscopic evidence for a preferential location of lidocaine inside phospholipid bilayers.
AuthorsFraceto LF, Pinto Lde M, Franzoni L, Braga AA, Spisni A, Schreier S, de Paula E
JournalBiophys Chem
PubMed ID12408938
We examined the effect of uncharged lidocaine on the structure and dynamics of egg phosphatidylcholine (EPC) membranes at pH 10.5 in order to assess the location of this local anesthetic in the bilayer. Changes in the organization of small unilamellar vesicles were monitored either by electron paramagnetic resonance (EPR)-in the ... More
Sphingolipids activate membrane fusion of Semliki Forest virus in a stereospecific manner.
The alphavirus Semliki Forest virus (SFV) enters cells through receptor-mediated endocytosis. Subsequently, triggered by the acid pH in endosomes, the viral envelope fuses with the endosomal membrane. Membrane fusion of SFV has been shown previously to be dependent on the presence of cholesterol in the target membrane. Recently, we have ... More