Differences in membrane fluidity and structure in contact inhibited and transformed cells

Studies on contact inhibited mouse embryo fibroblast 3T3 cells and 3T3 cells transformed by oncogenic RNA and DNA viruses and by a chemical carcinogen have demonstrated differences in plasma membrane architecture. Spin label and freeze fracture ultrastructural studies have shown that contact inhibited cells have ordered membrane lipids and aggregated intramembranous particles, whereas transformed cells have fluid membrane lipids and randomly distributed intramembranous particles. These findings suggest a model for how changes in the cell membrane may account for some of the characteristic differences observed between contact inhibited and transformed cells.