Lipid composition and lateral diffusion in plasma membranes of teratocarcinoma-derived cell lines

We measured lipid lateral diffusion rates for a series of teratocarcinoma-derived and embryo-derived cell lines, using the technique of fluorescence photo-bleaching recovery with a fluorescent lipid probe, C₁₆dil. The probe diffuses more rapidly in plasma membranes of embryonal carcinoma cells than in plasma membranes of teratocarcinoma-derived endodermal cell lines. When embryonal carcinoma cells are induced to differentiate by treatment with retinoic acid, diffusion constants of C₁₆dil are reduced to levels typical of endoderm. These changes are paralleled by differences in membrane cholesterol content; membrane free cholesterol levels in embyronal carcinoma lines are approximately half those found in endodermal lines, and are markedly increased upon retinoic-acid-induced differentiation.