Where would you expect to find proteins involved with movement of structures within a cell?

Ribosomes which are the protein factories, secrete their proteins into the Endoplasmic Reticulum. The Ribosomes attach themselves to the ER and secrete the proteins inside. Once inside the ER the proteins travel along the maze that is the Endoplasmic Reticulum until they reach the end of the ER. They then break out of the ER in a membranous sac known as a vesicle. From there the vesicle will transport the protein to different areas of the cell for work to be done.