Biochemical studies on cell fusion. II. Control of fusion response by lipid alteration.

Abstract

The preceding communication (Roos, D. S. and P. W. Choppin, 1985, J. Cell Biol. 101:1578-1590 described the lipid composition of a series of mouse fibroblast cell lines which vary in susceptibility to the fusogenic effects of polyethylene glycol (PEG). Two alterations in lipid content were found to be directly correlated with resistance to PEG-induced cell fusion: increases in fatty acyl chain saturation, and the elevation of neutral glycerides, including an unusual ether-linked compound. In this study, we have probed the association between lipid composition and cell fusion through the use of fatty acid supplements to the cellular growth medium, and show that the fusibility of cells can be controlled by altering their acyl chain composition. The parental Clone 1D cells contain moderately unsaturated fatty acids with a ratio of saturates to polyunsaturates (S/P) ,~ 1, and fuse virtually to completion following a standard PEG treatment. By contrast, the lipids of a highly fusion-resistant mutant cell line, F40, are highly saturated (S/P = 4). When the S/P ratio of Clone 1D cells was increased to approximate that normally found in F40 cells by growth in the presence of high concentrations of saturated fatty acids, they became highly resistant to PEG. Reduction of the S/P ratio of F40 cells by growth in cis-polyunsaturated fatty acids rendered them susceptible to fusion. Cell lines Fa, F16, etc., which are normally intermediate between Clone 1D and F40 in both lipid composition and fusion response, can be altered in either direction (towards either increased or decreased susceptibility to fusion) by the addition of appropriate fatty acids to the growth medium. Although trans-unsaturated fatty acids have phase-transition temperatures roughly similar to saturated compounds, and might therefore be expected to affect membrane fluidity in a similar manner, trans-unsaturated fatty acids exerted the same effect as cisunsaturates on the control of PEG-induced cell fusion. This observation suggests that the control of cell fusion by alteration of fatty acid content is not due to changes in membrane fluidity, and thus that the fatty acids are involved in some other way in the modulation of cell fusion.

Characterization of fusion from without induced by herpes simplex virus

“…This depends certainly on properties of the cell membranes in general [22,23,24], but especially on the presence of a receptor for HSV. WuDunn and Spear argued that heparans may have receptor activity for HSV [33].…”

Deletion of the Cytoplasmic Tail of the Fusion Protein of the Paramyxovirus Simian Virus 5 Affects Fusion Pore Enlargement

“…4). The lipid composition of cells has been shown to affect both fusion induced by polyethylene glycol (37,38) and fusion induced by viral proteins (39). Addition of lipids of various spontaneous curvature has also been seen to affect membrane fusion promoted by viral fusion proteins (6, 7).…”

Breast cancer is associated with an increase in the activity and expression of cholinephosphotransferase in rats

“…A number of studies have reported differences in lipid metabolism between mammary carcinomas and normal breast tissues; and breast cancer tissue to have much higher phospholipid contents than normal breast tissues (Sakai et al, 1992). It is known that alterations in membrane phospholipids are associated with malignant transformation (Dahiya et al, 1987), tumorigenicity (Roos and Choppin, 1985) and metastasis (Schroeder and Gardiner, 1984;Dahiya et al, 1992). The turnover of lipids, particularly phospholipids, is higher in carcinomas (Leach et al, 1998).…”