Promotion and inhibition of vesicle fusion by polylysine

Abstract

Polylysine induced rapid aggregation of large unilamellar vesicles composed of phosphatidylcholine-cardiolipin (1:1 molar ratio) but not their fusion. Application of the terbium-dipicolinic acid fusion assay showed that addition of polylysine at nanomolar concentrations enabled a significant lowering of the Ca2+ threshold concentration for vesicle fusion from 9 to 1 mM. Analysis of the kinetics of fusion with a mass-action kinetic model showed that polylysine enhanced significantly the rate of aggregation but affected only slightly the rate of fusion per se. Maximal enhancement of overall fusion rates occurred at a charge ratio (polylysine/cardiolipin) of about 0.5. At larger polylysine concentrations, e.g., at charge ratios greater than 3, polylysine inhibited vesicle fusion.

Interaction of Polylysine with the Cellular Receptor for Herpes Simplex Virus Type 1

“…It is quickly endocytosed by a non-receptor-mediated pathway (Shen et al, 1985) and, because of this property, has been used as a carrier molecule for methotrexate into methotrexate-resistant cells (Shen & Ryser, 1979;Shen et al, 1985). The polymer induces membrane fusion in in vitro systems (Walter et al, 1986;Uster & Deamer, 1985;Gad et al, 1985), and selective membrane leakage has been observed at relatively high doses (Bashford et al, 1986). Stimulation of brain triglyceride lipase (Le Petit et al, 1986), as well as of a protein (casein) kinase (Leiderman et al, 1985) have been reported.…”

Liposome-mediated introduction of the chloramphenicol acetyl transferase (CAT) gene and its expression in tobacco protoplasts

“…Polylysine, which is known to promote liposomeliposome fusion [9][10][11], enhanced the binding of DNA-containing liposomes to protoplasts (Fig. 1), but apparently decreased the efficiency of expression of the introduced gene as measured by the CAT assay (Fig.…”

Effect of surface charge on adsorption of bovine serum albumin 2. Interaction of protein molecules with an anionic monolayer, as studied by ellipsometry, radiotracer and surface tension measurements

“…The maximum solubilization would be obtained at pH below I.E.P and at the swamping concentration of protein. It seems that the solubilizing properties of proteins should be noted as one of the important functions of macromolecules, as well as their physiological role in biological membranes [27][28][29].…”