membrane proteins move randomly throughout the membrane, though generally at rates considerably less than would be measured in an artificial lipid bilayer (A).

Some membrane proteins fail to move and are considered to be immobilized(B).

a particular species of proteins is found to move in a highly directed manner toward one part of the cell or another (C).

Movement of protein D is restricted by other integral protein;

movement of protein E Is restricted by fences formed by proteins of the membrane skeleton;

movement of Protein F is restrained by extracellular materials.