Phospholipid diversity: Correlation with membrane–membrane fusion events

Abstract

The transport of various metabolically important substances along the endocytic and secretory pathways involves budding as well as fusion of vesicles with various intracellular compartments and plasma membrane. The membrane-membrane fusion events between various sub-compartments of the cell are believed to be mainly mediated by so-called "fusion proteins". This study shows that beside the proteins, lipid components of membrane may play an equally important role in fusion and budding processes. Inside out (ISO) as well as right side out (RSO) erythrocyte vesicles were evaluated for their fusogenic potential using conventional membrane fusion assay methods. Both fluorescence dequenching as well as content mixing assays revealed fusogenic potential of the erythrocyte vesicles. Among two types of vesicles, ISO were found to be more fusogenic as compared to the RSO vesicles. Interestingly, ISO retained nearly half of their fusogenic properties after removal of the proteins, suggesting the remarkable role of lipids in the fusion process. In another set of experiments, fusogenic properties of the liposomes (subtilosome), prepared from phospholipids isolated from Bacillus subtilis (a lower microbe) were compared with those of erythrocyte vesicles. We have also demonstrated that various types of vesicles upon interaction with macrophages deliver encapsulated materials to the cytosol of the cells. Membrane-membrane fusion was also followed by the study, in which a protein synthesis inhibitor ricin A (that does not cross plasma membrane), when encapsulated in the erythrocyte vesicles or subtilosomes was demonstrated to gain access to the cytosol.

Mechanism of Enhanced Activity of Liposome-Entrapped Aminoglycosides against Resistant Strains of Pseudomonas aeruginosa

“…The lipid mixing assay confirmed that the interaction between liposomes and bacteria is fusion while ruling out the possibility of adsorption or aggregation (6,44). Based on the assay's principle, fusion of fluorescent vesicles to nonfluorescent lipids, i.e., bacterial cells, results in probe dilution and a decrease in resonance energy transfer efficiency due to an increase in distance between NDB-PE and Rh-PE (40).…”

Dipalmitoleoylphosphoethanolamine as a PP2A Enhancer Obstructs Insulin Signaling by Promoting Ser/Thr Dephosphorylation of Akt

“…Phosphatidylethanolamine, which is the most abundant lipid on the cytoplasmic layer of cellular membranes, plays significant roles in cellular processes such as membrane fusion [17], cell cycle [18], autophagy [19], apoptosis [20], and cognitive function [21]. Three main biochemical pathways are recognized for production of phosphatidylethanolamine; CDP-ethanolamine Kennedy pathway, mitochondrial phosphatidylserine decarboxylation pathway catalyzed by phosphatidylserine decarboxylase, and acylation of lysophosphatidylethanolamine catalyzed by lysophosphatidylethanolamine acyltransferase.…”

Dietary Phospholipids and Phytostrerols: A Review on Some Nigerian Vegetable Oils

“…PE is the most abundant lipid on the cytoplasmic layer of cellular membranes, with significant roles in cellular processes such as membrane fusion [54], cell cycle [55], autophagy [56], and apoptosis [57]. The phosphatidylethanolamine ranges from 1.13 in small alligator peppers to 558.00 mg/100 g in malaba spinach.…”