Clathrin itself plays no part in choosing specific molecules for transport. Choosing molecules for transport is the function of a class of coat proteins called adaptins, which secure the clathrin coat to the vesicle membrane and help select cargo molecules for transport. You have discovered two adaptin proteins, adaptin-1 and adaptin-2, are involved in binding cargo at the plasma membrane or the Golgi apparatus. Based on some preliminary biochemical data, you hypothesize that adaptin-1 is necessary for transporting cargo from the plasma membrane to endosomes. Which test would you design to track adaptin-1 as it moves through a hypothetical cell