Phosphatidylserine vesicles

We have proposed that vesicle aggregation is probably related to the disposition of pardaxin bound in the phosphatidylserine vesicle lipid bilayer (26). This conclusion is supported by the observation that phosphatidycholine vesicles are not induced to aggregate and that the pardaxin-induced phosphatidylserine vesicle aggregation is affected by charge polarization of the vesicle (26). This suggestion seems to be consistent also with the voltage dependence of fast "pore" activity of pardaxin, the channels which are open only at positive membrane potentials. 

Most probably the presence of pardaxin pores alters the structure of the bilayer resulting in aggregation of phosphatidylserine vesicles mediated by contact but not by partial merging of their membranes. 

Cocco, L., Martelli, A., Billi, A., Matteucci, A., Vitale, M., Neri, L., and Manzoli, F. (1986) Changes in nucleosome structure and histone H3 accessibility. Iodoacetamidofluorescein labeling after treatment with phosphatidylserine vesicles. Exp. Cell Res. 166, 465 174. 

Wilschut, J., Duzgunes, N., Fraley, R., and Papahadjopoulos, D. (1980). Studies on the mechanism of membrane-fiision - kinetics of calcium-ion induced fusion of phosphatidylserine vesicles followed by a new assay for mixing of aqueous vesicle contents. Biochemistry, 19, 6011-21. 

II labeling after treatment with phosphatidylserine vesicles. Exp. Cell Res. 166, 465—474. 

F. Aranda et al., Influence of a-tocopherol incorporation on Ca-induced fusion of phosphatidylserine vesicles. Arch. Biochem. Biophys., 333 (1996) 394-400. 

The relaxation rate enhancements for Na in the presence of phosphatidylserine vesicles are moderate (a maximum of 40 Hz), and the motional narrowing condition prevails the magnetization... 

Marie-Pierre Krafft at the Institut Charles Sadron, Strasbourg, has studied the polymerization of hydrophobic monomers such as isodecylacrylate (ISODAC) in small rmil-amellar vesicles of perfluoroalkylated phosphatidylcholine (F-PC). The process was compared with that for polymerization of ISODAC in egg PC vesicles. In the case of F-PC vesicles the formed pol3mer was homogeneously distributed throughout the vesicles whereas for egg-PC, parachute polymerization was found to be operative. Ferro and Krafft have also studied the effect of addition of semi-fluorinated alkanes (C jH2 j+iC F2 +i, H jF ) such as HioFe on Ca -induced fusion and the rate of release of 5,6-carboxyfluorescein referred to as (CF) from the water cores of the vesicles. For HioFg, the rate of fusion was reduced by an order of magnitude, and there was a 40-fold decrease in the rate of release of CF, as compared with phosphatidylserine vesicles as a reference. 

R38. Phosphorus-31 and sodium-23 studies of diamagnetic metal ion binding to phosphatidylserine vesicles Kurland, R. J. NATO Adv. Stud. Inst. Ser. C 1980, 61, 655. 

Discuss the effects on the lipid phase transition of pure dimyris-toyl phosphatidylcholine vesicles of added (a) divalent cations, (b) cholesterol, (c) distearoyl phosphatidylserine, (d) dioleoyl phosphatidylcholine, and (e) integral membrane proteins. 

Farge, E., 1995, Increased vesicle endocytosis due to an increase in the plasma membrane phosphatidylserine concentration. Biophys. J., 69 2501-2506. 

Comfurius, P., Smeets, E.F., Willems, G.M., Bevers, E.M., and Zwaal,R.F.A., 1994, Assembly of the prothrombinase complex on the hpid vesicles dependent on the stereochemical configuration of polar headgroup of phosphatidylserine. Biochemistry 33 10319-10324. 

Tail, J.F., and Smith, C., 1999, Phosphatidylserine receptor Role of CD36 in binding of anionic phospholipid vesicles to monocytic cells, J. Biol. Chem. 274 3048-3054. 

Abbreviations. HA, hemagglutinin DRV, dehydration-rehydration vesicles PC, phosphatidylcholine DOPE, dioleoyl phosphatidylcholine DOTAP, l,2-dioleyloxy-3-(trimethylamonium propane) BisHOP,, 2-bis (hexadecylcycloxy)-3-trimethylamino propane DC-CHOL, 3p(V,V,-dimethylami-noethane)-carbamyl cholesterol (DC-CHOL) DOTMA, V-[l-(2,3-dioleyloxy) propyl]-iV,V,V-triethylammonium PG, phosphatidyl glycerol PS, phosphatidylserine SA, stearylamine DODAP, l,2-dioleyloxy-3-(dimethylamonium propane). 

Fig. 8 Capillary EKC separations of (A) acetophenone (1), propiophenone (2), butyrophenone (3), valerophenone (4), and hexanophenone (5) on vesicles composed of sodium dodecylsulfate and ra-dodecyltrimethylammoniumbromide at pH 7.2, (B,C) of 1-dehydroaldosterone (1), cortisone (2), cortisol (3), 21-deoxycortisol (4), 11-deoxycortisol (5), and dexamethasone (6) on liposomes composed of 1-palmitoyl-2-oleoyl-sra-glycero-3-phosphocholine (80%) and (B) phosphatidylserine or (C) car-diolipin at pH 9, lipid concentrations (B) 2.4 mM and 0.6 mM, (C) 3.6 and 0.9 mM. (Part A is reprinted with permission from Ref. 59, copyright 1998 American Chemical Society Parts B and C are reprinted with permission from Ref. 33, copyright 2000 Wiley-VCH Verlag, all with slight modifications.)...

PKC is a serine/threonine protein kinase comprised of at least 11 isozymic forms (Nishizuka 1995 Liu and Heckman 1998). These isozymic forms have been classified as atypical, classical, and novel. Classical PKCs (a, pi, pH, and y) are activated by Ca2+, DAG, phosphatidylserine (PS), and the tumor promoter phorbol 12-myristate 13-acetate (PMA). Novel PKCs (6, e, r, i, and 0) are activated by DAG, PS, and unsaturated fatty acids, while atypical PKCs (C, A, and 0 are insensitive to DAG but are activated by PS and phosphatidylinositides (reviewed in Liu and Heckman 1998 Newton and Johnson 1998 Nakanishi et al. 1993). PKCs have been implicated in a wide variety of cellular responses, including growth, differentiation, gene expression, angiogenesis, contractility, and vesicle trafficking (Nishizuka 1995). 

Cochleates can also be used for plasmid delivery. A negatively charged phospholipid such as phosphatidylserine, phosphatidic acid or phosphatidyl glycerol, in the absence or presence of cholesterol, are utilized to produce a suspension of multilamellar vesicles containing plasmids, which are then converted to small unilamellar vesicles by sonication. These vesicles are dialyzed against buffered divalent cations (e.g. calcium chloride) to produce an insoluble precipitate referred to as cochleates. Cochleates have been shown to encapsulate plasmid and enhance plasmid stability and transfection efficiency. 

Large Unilamellar Vesicles from Cochleates Large unilamellar vesicles can be produced with the cochleate approach [139], Small unilamellar vesicles consisted from phosphatidylserine adopt a cochleate shape after addition of calcium. Addition of EDTA creates complexes with calcium, turning the cochleates to LUVs. 

Hoekstra, D. (1982), Fluorescence method for measuring the kinetics of Ca2+-induced phase separations in phosphatidylserine-containing lipid vesicles, Biochemistry, 21, 1055-1061. 

We now turn to the factors that affect vesicle properties. For anionic phospholipids, the optimum surface area Qq may be expected to be larger at higher pH or lower ionic strength. This will result in the formation of smaller vesicles, as observed for phosphatidylserine at different ionic strengths. ... 

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