Early and late changes in the glycoproteins of Friend erythroleukemia cells induced to differentiate.

Incorporation of labeled fucose and galactose into Friend virus-transformed murine erythroleukemia cells, uninduced and induced to differentiate by hexamethylene bisacetamide, was followed during the first 4 days of treatment. The plasma membrane and microsomal-mitochondrial fractions of the cells were isolated and purified. The rate of fucose and galactose incorporation into membranal proteins was markedly stimulated in the induced cells as compared to the uninduced cells. However, the total amount of the label incorporated was decreased. Binding of wheat germ agglutinin to M.W. 140,000 and 90,000 bands of the plasma membrane was increased within 24 hr of induction and occurred at the same time as increased fucose incorporation into protein bands of similar size. Stimulation of concanavalin A binding to the plasma membrane proteins within 74 hr of induction was correlated with increased galactose incorporation into M.W. 32,000 and 64,000 bands which were tentatively identified as the glycophorin bands.