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 photobleaching 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 embryonal carcinoma lines are approximately half those found in endodermal lines, and are markedly increased upon retinoic-acid-induced differentiation.