The majority of the proteins conveyed to the endoplasmic reticulum possess a sequence of 5 to 10 hydrophobic amino acids on their N-terminal end. The greater part of these proteins is transported from the ER to the cell’s Golgi apparatus for processing and packaging. If they possess a certain retention sequence of 4 amino acids (KDEL; lys-asp-glu-leu) at their C-terminal end, however, the proteins normally do not leave the ER. In cases where they manage to exit the organelle, the proteins are rerouted back to it once they reach the KDEL receptors present in the Golgi apparatus. The Golgi apparatus was labeled in the digital video sequences of fox lung cells presented in this section with mApple and mitochondria were visualized with mEmerald.