Subcellular localization of Mpl fusion proteins.

COS-1 cells were transiently transfected with constructs encoding either the membrane-targeted Mpl or the cytoplasmic Mpl fusion protein. Whole cell lysates, membrane fractions, and cytoplasmic fractions were obtained and analyzed by Western blotting with an antibody directed against the HA epitope tag. Lanes 1, 3, 5: membrane-targeted Mpl construct; lanes 2, 4, 6: cytoplasmic Mpl construct; lanes 1, 2: whole cell lysate; lanes 3, 4: cytoplasmic fraction; lanes 5, 6: membrane fraction.