Membrane fusion

Abstract

The factors involved in the regulation of biological membrane fusion and models proposed for the molecular mechanism of biomembrane fusion are reviewed. The results obtained in model systems are critically discussed in the light of the known properties of biomembranes and characteristics of biomembrane fusion. Biological membrane fusion is a local-point event; extremely fast, non-leaky, and under strict control. Fusion follows on a local and most probably protein-modulated destabilization, and a transition of the interacting membranes from a bilayer to a non-bilayer lipid structure. The potential role of type II non-bilayer preferring lipids and of proteins in the local destabilization of the membranes is evaluated. Proteins are not only responsible for the mutual recognition of the fusion partners, but are most likely also to be involved in the initiation of biomembrane fusion, by locally producing or activating fusogens, or by acting as fusogens.

Fusion of Lamellar Body with Plasma Membrane Is Driven by the Dual Action of Annexin II Tetramer and Arachidonic Acid

“…X-ray diffraction study revealed that arachidonic acid may destabilize membrane by converting closely associated lipid bilayers into hexagonal structure to promote membrane fusion (66). Another study also suggested that arachidonic acid favors the transition of membrane bilayers by a lipid arrangement to an HII phase, which is important for membrane fusion (67). Arachidonic acid may also promote the ''stalk'' formation (68).…”

Phospholipids in animal eukaryotic membranes: transverse asymmetry and movement

“…The liberation of these vesicles, as well as the exocytosis of the cell granules, involve the fusion (or fission) of opposing zones of membrane. At the point of fusion/fission, transient non-bilayer structures will appear (Burger and Verkleij, 1990;Sims et al, 1989), allowing a fast mixing of the components within the bilayers. Once these events have ceased, the aminophospholipid translocase should restore the internal localization of phosphatidylserine and phosphatidylethanolamine.…”

“…Later, it was shown that fusion proceeds approximately ten times more rapidly than phase separation and that Mg2+, which can induce fusion at high concentrations, does not induce phase separation (Hoekstra, 1982). A more recent hypothesis is that destabilization is generated by non-bilayer structures (Ellens et al, 1989) and that fusion between the two membranes occurs at a local point (Burger and Verkleij, 1990). Amongst lipids which easily form non-bilayer phases is phosphatidylethanolamine, abundant in cytoplasmic membrane leaflets.…”

Cell Signaling through the Protein Kinases cAMP-dependent Protein Kinase, Protein Kinase Cϵ, and RAF-1 Regulates Amphotropic Murine Leukemia Virus Envelope Protein-induced Syncytium Formation

“…Membrane fusion is a central process in fertilization, myogenesis, osteogenesis, placenta formation, and virus infection (40). Retrovirus-induced cell-cell fusion and the formation of multinucleated giant cells (syncytia) are induced as a consequence of interactions between the virus en- …”