We can understand the dynamics, trajectories and interaction of single molecules and vesicles in cells. This video shows TRP channel proteins tagged with mCherry and expressed in HEK cells. They are transported to the plasma membrane in vesicles, which are visible as the highly dynamic bright fluorescent spots moving throughout the cells. In the image above, the trajectories followed by the vesicles were mapped out using Nanoimager tracking software. The image on the right show single RNA polymerase enzymes tagged with PA-mCherry and tracked using single-particle tracking photoactivated localization microscopy.