Lateral transport of a lipid probe and labeled proteins on a cell membrane.

Diffusion coefficients (D) of a lipid probe and labeled proteins on L-6 myoblast membranes have been measured giving D(protein) approximately 2 X 10(-10) square centimeter per second and D (lipid probe) approximately 9 X 10(-9) square centimeter per second. Some of the membrane proteins are immobile, but the lipid probe diffuses freely over macroscopic distances. Cytochalasin B slows protein but not lipid probe diffusion.