Cytoskeletal influence on merocyanine 540 receptors in the plasma membrane of erythroleukemic cells

When human erythroleukemic cells are induced to differentiate in vitro, the lipids in the plasma membrane that bind the fluorescent dye merocyanine 540 are redistributed into a cap at one pole of the cell. This capping phenomenon can also be observed in uninduced cells that have been incubated with cytochalasin B, an agent which disrupts actin-containing microfilaments or with local anesthetics which act on both microfilaments and microtubules. Colchicine which acts on microtubules, however, has no effect. This suggests that the uniform distribution seen in uninduced cells is maintained by the cytoskeletal microfilaments and that loss of these structures leads to spontaneous redistribution of merocyanine 540-binding sites.